/* Distributed under the Apache License, Version 2.0.
   See accompanying NOTICE file for details.*/

#include "stdafx.h"
#include "physiology/Cardiovascular.h"
#include "physiology/Saturation.h"
#include "controller/Circuits.h"
#include "controller/Compartments.h"
#include "controller/Substances.h"
#include "PulseConfiguration.h"
// Conditions
#include "engine/SEConditionManager.h"
#include "patient/conditions/SEChronicAnemia.h"
#include "patient/conditions/SEChronicHeartFailure.h"
#include "patient/conditions/SEChronicPericardialEffusion.h"
#include "patient/conditions/SEChronicRenalStenosis.h"
// Actions
#include "engine/SEActionManager.h"
#include "engine/SEPatientActionCollection.h"
#include "patient/actions/SEBrainInjury.h"
#include "patient/actions/SEChestCompressionForce.h"
#include "patient/actions/SEChestCompressionForceScale.h"
#include "patient/actions/SEHemorrhage.h"
#include "patient/actions/SEPericardialEffusion.h"
// Dependent Systems
#include "system/physiology/SEBloodChemistrySystem.h"
#include "system/physiology/SEDrugSystem.h"
#include "system/physiology/SEEnergySystem.h"
#include "system/physiology/SENervousSystem.h"
// CDM
#include "patient/SEPatient.h"
#include "engine/SEEventManager.h"
#include "substance/SESubstance.h"
#include "substance/SESubstanceTransport.h"
#include "circuit/fluid/SEFluidCircuit.h"
#include "circuit/fluid/SEFluidCircuitCalculator.h"
#include "compartment/fluid/SELiquidCompartmentGraph.h"
#include "compartment/fluid/SEGasCompartment.h"
#include "compartment/substances/SELiquidSubstanceQuantity.h"
#include "properties/SEScalar0To1.h"
#include "properties/SEScalarPressure.h"
#include "properties/SEScalarFrequency.h"
#include "properties/SEScalarMass.h"
#include "properties/SEScalarMassPerVolume.h"
#include "properties/SEScalar0To1.h"
#include "properties/SEScalarForce.h"
#include "properties/SEScalarElectricPotential.h"
#include "properties/SEScalarTime.h"
#include "properties/SEScalarPressurePerVolume.h"
#include "properties/SEScalarPressureTimePerVolume.h"
#include "properties/SEScalarPower.h"
#include "properties/SEScalarTemperature.h"
#include "properties/SEScalarAmountPerVolume.h"
#include "properties/SEScalarVolume.h"
#include "properties/SEScalarVolumePerTime.h"
#include "properties/SEScalarVolumePerPressure.h"
#include "properties/SEScalarVolumePerTimeArea.h"
#include "properties/SEScalarArea.h"
#include "properties/SEScalarPressureTimePerVolumeArea.h"
#include "properties/SERunningAverage.h"
#include "utils/DataTrack.h"
#include "utils/GeneralMath.h"

Cardiovascular::Cardiovascular(PulseData& data) : PulseCardiovascularSystem(data.GetLogger()), m_data(data)
{
  m_TuningFile = "";
  m_transporter = new SELiquidTransporter(VolumePerTimeUnit::mL_Per_s, VolumeUnit::mL, MassUnit::ug, MassPerVolumeUnit::ug_Per_mL, data.GetLogger());
  m_circuitCalculator = new SEFluidCircuitCalculator(VolumePerPressureUnit::mL_Per_mmHg, VolumePerTimeUnit::mL_Per_s, PressureTimeSquaredPerVolumeUnit::mmHg_s2_Per_mL, PressureUnit::mmHg, VolumeUnit::mL, PressureTimePerVolumeUnit::mmHg_s_Per_mL, data.GetLogger());
  m_CardiacCycleArterialPressure_mmHg = new SERunningAverage();
  m_CardiacCycleArterialCO2PartialPressure_mmHg = new SERunningAverage();
  m_CardiacCyclePulmonaryCapillariesWedgePressure_mmHg = new SERunningAverage();
  m_CardiacCyclePulmonaryCapillariesFlow_mL_Per_s = new SERunningAverage();
  m_CardiacCyclePulmonaryShuntFlow_mL_Per_s = new SERunningAverage();
  m_CardiacCyclePulmonaryArteryPressure_mmHg = new SERunningAverage();
  m_CardiacCycleCentralVenousPressure_mmHg = new SERunningAverage();
  m_CardiacCycleSkinFlow_mL_Per_s = new SERunningAverage();
  Clear();
}

Cardiovascular::~Cardiovascular()
{
  Clear();
  delete m_transporter;
  delete m_circuitCalculator;
  delete m_CardiacCycleArterialPressure_mmHg;
  delete m_CardiacCycleArterialCO2PartialPressure_mmHg;
  delete m_CardiacCyclePulmonaryCapillariesWedgePressure_mmHg;
  delete m_CardiacCyclePulmonaryCapillariesFlow_mL_Per_s;
  delete m_CardiacCyclePulmonaryShuntFlow_mL_Per_s;
  delete m_CardiacCyclePulmonaryArteryPressure_mmHg;
  delete m_CardiacCycleCentralVenousPressure_mmHg;
  delete m_CardiacCycleSkinFlow_mL_Per_s;
}

void Cardiovascular::Clear()
{
  SECardiovascularSystem::Clear();

  m_CirculatoryCircuit = nullptr;
  m_CirculatoryGraph = nullptr;

  m_AortaCompliance = nullptr;
  m_AortaResistance = nullptr;
  m_VenaCavaCompliance = nullptr;
  m_RightHeartResistance = nullptr;

  m_MainPulmonaryArteries = nullptr;
  m_LeftHeart2 = nullptr;

  m_LeftPulmonaryArteriesToVeins = nullptr;
  m_LeftPulmonaryArteriesToCapillaries = nullptr;
  m_RightPulmonaryArteriesToVeins = nullptr;
  m_RightPulmonaryArteriesToCapillaries = nullptr;

  m_InternalHemorrhageToAorta = nullptr;
  m_pAortaToBone = nullptr;
  m_pAortaToBrain = nullptr;
  m_pBrainToVenaCava = nullptr;
  m_pAortaToLiver = nullptr;
  m_pAortaToLeftKidney = nullptr;
  m_pAortaToLargeIntestine = nullptr;
  m_pAortaToMuscle = nullptr;
  m_pMuscleToVenaCava = nullptr;
  m_pAortaToMyocardium = nullptr;
  m_pMyocardiumToVenaCava = nullptr;
  m_pAortaToRightKidney = nullptr;
  m_pAortaToSkin = nullptr;
  m_pAortaToSmallIntestine = nullptr;
  m_pAortaToSplanchnic = nullptr;
  m_pAortaToSpleen = nullptr;

  m_pGndToAbdominalCavity = nullptr;
  m_pAbdominalCavityToGnd = nullptr;

  m_pGndToPericardium = nullptr;
  m_pPericardiumToGnd = nullptr;
  m_pRightHeartToGnd = nullptr;
  m_pRightHeart = nullptr;
  m_pLeftHeartToGnd = nullptr;
  m_pLeftHeart = nullptr;
  m_LeftHeartToAorta = nullptr;

  m_leftRenalArteryPath = nullptr;
  m_rightRenalArteryPath = nullptr;

  m_Aorta = nullptr;
  m_AortaCO2 = nullptr;
  m_Groundcmpt = nullptr;
  m_LeftHeart = nullptr;
  m_LeftPulmonaryCapillaries = nullptr;
  m_LeftPulmonaryArteries = nullptr;
  m_LeftPulmonaryVeins = nullptr;
  m_Pericardium = nullptr;
  m_RightHeart = nullptr;
  m_RightPulmonaryCapillaries = nullptr;
  m_RightPulmonaryArteries = nullptr;
  m_RightPulmonaryVeins = nullptr;
  m_VenaCava = nullptr;
  m_AbdominalCavity = nullptr;

  m_leftPleuralCavity = nullptr;
  m_rightPleuralCavity = nullptr;

  m_CardiacCycleArterialPressure_mmHg->Clear();
  m_CardiacCycleArterialCO2PartialPressure_mmHg->Clear();
  m_CardiacCyclePulmonaryCapillariesWedgePressure_mmHg->Clear();
  m_CardiacCyclePulmonaryCapillariesFlow_mL_Per_s->Clear();
  m_CardiacCyclePulmonaryShuntFlow_mL_Per_s->Clear();
  m_CardiacCyclePulmonaryArteryPressure_mmHg->Clear();
  m_CardiacCycleCentralVenousPressure_mmHg->Clear();
  m_CardiacCycleSkinFlow_mL_Per_s->Clear();

  m_HemorrhageLinks.clear();
  m_HemorrhagePaths.clear();

  m_InternalHemorrhageLinks.clear();
  m_InternalHemorrhagePaths.clear();
}

//--------------------------------------------------------------------------------------------------
/// \brief
/// Initializes system properties.
//--------------------------------------------------------------------------------------------------
void Cardiovascular::Initialize()
{
  PulseSystem::Initialize();

  m_HeartRhythm = eHeartRhythm::NormalSinus;

  m_StartSystole = true;
  m_HeartFlowDetected = false;
  m_CardiacCyclePeriod_s = 0.8; //seconds per beat
  m_CardiacCycleDiastolicVolume_mL = 0.0;
  m_CardiacCycleStrokeVolume_mL = 0;
  m_CurrentCardiacCycleDuration_s = 0;

  //Heart Elastance Parameters
  m_LeftHeartElastance_mmHg_Per_mL = 0.0;
  m_LeftHeartElastanceMax_mmHg_Per_mL = m_data.GetConfiguration().GetLeftHeartElastanceMaximum(PressurePerVolumeUnit::mmHg_Per_mL);
  m_LeftHeartElastanceMin_mmHg_Per_mL = m_data.GetConfiguration().GetLeftHeartElastanceMinimum(PressurePerVolumeUnit::mmHg_Per_mL);
  m_LeftHeartElastanceModifier = 1.0; //Utilized for reducing the maximum elastance to represent left ventricular systolic dysfunction
  m_RightHeartElastance_mmHg_Per_mL = 0.0;
  m_RightHeartElastanceMax_mmHg_Per_mL = m_data.GetConfiguration().GetRightHeartElastanceMaximum(PressurePerVolumeUnit::mmHg_Per_mL);
  m_RightHeartElastanceMin_mmHg_Per_mL = m_data.GetConfiguration().GetRightHeartElastanceMinimum(PressurePerVolumeUnit::mmHg_Per_mL);
  
  // CPR and Cardiac Arrest control
  m_EnterCardiacArrest = false;
  m_CompressionTime_s = 0.0;
  m_CompressionRatio = 0.0;
  m_CompressionPeriod_s = 0.0;

  //Initialize system data based on patient file inputs
  GetBloodVolume().Set(m_data.GetCurrentPatient().GetBloodVolumeBaseline());
  m_CardiacCycleAortaPressureHigh_mmHg = m_data.GetCurrentPatient().GetSystolicArterialPressureBaseline(PressureUnit::mmHg);
  m_CardiacCycleAortaPressureLow_mmHg = m_data.GetCurrentPatient().GetDiastolicArterialPressureBaseline(PressureUnit::mmHg);
  GetMeanArterialPressure().SetValue((2. / 3.*m_CardiacCycleAortaPressureLow_mmHg) + (1. / 3.*m_CardiacCycleAortaPressureHigh_mmHg), PressureUnit::mmHg);
  m_CardiacCycleArterialPressure_mmHg->Sample(GetMeanArterialPressure().GetValue(PressureUnit::mmHg));
  m_CardiacCyclePulmonaryArteryPressureHigh_mmHg = 26;
  m_CardiacCyclePulmonaryArteryPressureLow_mmHg = 9;
  GetPulmonaryMeanArterialPressure().SetValue(15, PressureUnit::mmHg);
  GetHeartRate().Set(m_data.GetCurrentPatient().GetHeartRateBaseline());
  RecordAndResetCardiacCycle();  
  
  // Set system data based on physiology norms
  GetMeanCentralVenousPressure().SetValue(5.0, PressureUnit::mmHg);
  m_CardiacCycleArterialCO2PartialPressure_mmHg->Sample(60.0);
  m_LastCardiacCycleMeanArterialCO2PartialPressure_mmHg = 60.0;
  GetMeanArterialCarbonDioxidePartialPressure().SetValue(60, PressureUnit::mmHg);
  GetMeanArterialCarbonDioxidePartialPressureDelta().SetValue(0.0, PressureUnit::mmHg);
  GetPulmonaryCapillariesWedgePressure().SetValue(0, PressureUnit::mmHg);
  GetPulmonaryMeanArterialPressure().SetValue(90, PressureUnit::mmHg);
  GetPulmonaryArterialPressure().SetValue(90, PressureUnit::mmHg);
  GetPulmonaryMeanCapillaryFlow().SetValue(0, VolumePerTimeUnit::mL_Per_s);
  GetPulmonaryMeanShuntFlow().SetValue(0, VolumePerTimeUnit::mL_Per_s);

  GetMeanSkinFlow().SetValue(0, VolumePerTimeUnit::mL_Per_s);
  GetCardiacOutput().SetValue(5600, VolumePerTimeUnit::mL_Per_min);
  GetHeartStrokeVolume().SetValue(78, VolumeUnit::mL);
  GetHeartEjectionFraction().SetValue(0.55);
  GetCardiacIndex().SetValue(3.0, VolumePerTimeAreaUnit::mL_Per_min_m2);
  GetPulmonaryVascularResistance().SetValue(0.14, PressureTimePerVolumeUnit::mmHg_min_Per_mL);
  GetPulmonaryVascularResistanceIndex().SetValue(0.082, PressureTimePerVolumeAreaUnit::mmHg_min_Per_mL_m2);

  m_CurrentCardiacCycleTime_s = 0.0;

  CalculateHeartElastance();

  double systemicVascularResistance_mmHg_s_Per_mL = (GetMeanArterialPressure().GetValue(PressureUnit::mmHg) - GetMeanCentralVenousPressure().GetValue(PressureUnit::mmHg)) / GetCardiacOutput().GetValue(VolumePerTimeUnit::mL_Per_s);
  GetSystemicVascularResistance().SetValue(systemicVascularResistance_mmHg_s_Per_mL, PressureTimePerVolumeUnit::mmHg_s_Per_mL);
  // This is not part of stabilization due to not knowing when we hit the patient parameters with a circuit configuration
  TuneCircuit();
  systemicVascularResistance_mmHg_s_Per_mL = (GetMeanArterialPressure().GetValue(PressureUnit::mmHg) - GetMeanCentralVenousPressure().GetValue(PressureUnit::mmHg)) / GetCardiacOutput().GetValue(VolumePerTimeUnit::mL_Per_s);
  GetSystemicVascularResistance().SetValue(systemicVascularResistance_mmHg_s_Per_mL, PressureTimePerVolumeUnit::mmHg_s_Per_mL);
  m_LeftHeartElastanceMax_mmHg_Per_mL = m_data.GetConfiguration().GetLeftHeartElastanceMaximum(PressurePerVolumeUnit::mmHg_Per_mL);
  m_RightHeartElastanceMax_mmHg_Per_mL = m_data.GetConfiguration().GetRightHeartElastanceMaximum(PressurePerVolumeUnit::mmHg_Per_mL);
}

//--------------------------------------------------------------------------------------------------
/// \brief
/// Initializes parameters for Cardiovascular Class
///
///  \details
///   Initializes member variables and system level values on the common data model.
//--------------------------------------------------------------------------------------------------
void Cardiovascular::SetUp()
{
  m_dT_s = m_data.GetTimeStep().GetValue(TimeUnit::s);
  m_minIndividialSystemicResistance__mmHg_s_Per_mL = 0.1;

  //Circuits
  m_CirculatoryCircuit = &m_data.GetCircuits().GetActiveCardiovascularCircuit();
  m_CirculatoryGraph = &m_data.GetCompartments().GetActiveCardiovascularGraph();
  //Compartments
  m_Aorta = m_data.GetCompartments().GetLiquidCompartment(pulse::VascularCompartment::Aorta);
  m_AortaCO2 = m_Aorta->GetSubstanceQuantity(m_data.GetSubstances().GetCO2());
  m_Brain = m_data.GetCompartments().GetLiquidCompartment(pulse::VascularCompartment::Brain);
  m_Groundcmpt = m_data.GetCompartments().GetLiquidCompartment(pulse::VascularCompartment::Ground);
  m_LeftPulmonaryArteries = m_data.GetCompartments().GetLiquidCompartment(pulse::VascularCompartment::LeftPulmonaryArteries);
  m_RightPulmonaryArteries = m_data.GetCompartments().GetLiquidCompartment(pulse::VascularCompartment::RightPulmonaryArteries);
  m_LeftPulmonaryVeins = m_data.GetCompartments().GetLiquidCompartment(pulse::VascularCompartment::LeftPulmonaryVeins);
  m_RightPulmonaryVeins = m_data.GetCompartments().GetLiquidCompartment(pulse::VascularCompartment::RightPulmonaryVeins);
  m_LeftPulmonaryCapillaries = m_data.GetCompartments().GetLiquidCompartment(pulse::VascularCompartment::LeftPulmonaryCapillaries);
  m_RightPulmonaryCapillaries = m_data.GetCompartments().GetLiquidCompartment(pulse::VascularCompartment::RightPulmonaryCapillaries);
  m_VenaCava = m_data.GetCompartments().GetLiquidCompartment(pulse::VascularCompartment::VenaCava);
  m_Pericardium = m_data.GetCompartments().GetLiquidCompartment(pulse::VascularCompartment::Pericardium);
  m_LeftHeart = m_data.GetCompartments().GetLiquidCompartment(pulse::VascularCompartment::LeftHeart);
  m_RightHeart = m_data.GetCompartments().GetLiquidCompartment(pulse::VascularCompartment::RightHeart);
  m_AbdominalCavity = m_data.GetCompartments().GetLiquidCompartment(pulse::VascularCompartment::AbdominalCavity);
  //Respiratory Compartments
  m_leftPleuralCavity = m_data.GetCompartments().GetGasCompartment(pulse::PulmonaryCompartment::LeftPleuralCavity);
  m_rightPleuralCavity = m_data.GetCompartments().GetGasCompartment(pulse::PulmonaryCompartment::RightPleuralCavity);
  //Nodes
  m_MainPulmonaryArteries = m_CirculatoryCircuit->GetNode(pulse::CardiovascularNode::MainPulmonaryArteries);
  m_LeftHeart2 = m_CirculatoryCircuit->GetNode(pulse::CardiovascularNode::LeftHeart2);
  m_Ground = m_CirculatoryCircuit->GetNode(pulse::CardiovascularNode::Ground);
  //Paths
  m_LeftPulmonaryArteriesToVeins = m_CirculatoryCircuit->GetPath(pulse::CardiovascularPath::LeftPulmonaryArteriesToLeftPulmonaryVeins);
  m_LeftPulmonaryArteriesToCapillaries = m_CirculatoryCircuit->GetPath(pulse::CardiovascularPath::LeftPulmonaryArteriesToLeftPulmonaryCapillaries);
  m_RightPulmonaryArteriesToVeins = m_CirculatoryCircuit->GetPath(pulse::CardiovascularPath::RightPulmonaryArteriesToRightPulmonaryVeins);
  m_RightPulmonaryArteriesToCapillaries = m_CirculatoryCircuit->GetPath(pulse::CardiovascularPath::RightPulmonaryArteriesToRightPulmonaryCapillaries);

  m_InternalHemorrhageToAorta = m_CirculatoryCircuit->GetPath(pulse::CardiovascularPath::GroundToAorta4);
  m_pAortaToBone = m_CirculatoryCircuit->GetPath(pulse::CardiovascularPath::Aorta1ToBone1);
  m_pAortaToBrain = m_CirculatoryCircuit->GetPath(pulse::CardiovascularPath::Aorta1ToBrain1);
  m_pBrainToVenaCava = m_CirculatoryCircuit->GetPath(pulse::CardiovascularPath::Brain1ToBrain2);
  m_pAortaToLiver = m_CirculatoryCircuit->GetPath(pulse::CardiovascularPath::Aorta1ToLiver1);
  m_pAortaToLeftKidney = m_CirculatoryCircuit->GetPath(pulse::CardiovascularPath::Aorta1ToLeftKidney1);
  m_pAortaToLargeIntestine = m_CirculatoryCircuit->GetPath(pulse::CardiovascularPath::Aorta1ToLargeIntestine);
  m_pAortaToMuscle = m_CirculatoryCircuit->GetPath(pulse::CardiovascularPath::Aorta1ToMuscle1);
  m_pMuscleToVenaCava = m_CirculatoryCircuit->GetPath(pulse::CardiovascularPath::Muscle1ToMuscle2);
  m_pAortaToMyocardium = m_CirculatoryCircuit->GetPath(pulse::CardiovascularPath::Aorta1ToMyocardium1);
  m_pMyocardiumToVenaCava = m_CirculatoryCircuit->GetPath(pulse::CardiovascularPath::Myocardium1ToMyocardium2);
  m_pAortaToRightKidney = m_CirculatoryCircuit->GetPath(pulse::CardiovascularPath::Aorta1ToRightKidney1);
  m_pAortaToSkin = m_CirculatoryCircuit->GetPath(pulse::CardiovascularPath::Aorta1ToSkin1);
  m_pAortaToSmallIntestine = m_CirculatoryCircuit->GetPath(pulse::CardiovascularPath::Aorta1ToSmallIntestine);
  m_pAortaToSplanchnic = m_CirculatoryCircuit->GetPath(pulse::CardiovascularPath::Aorta1ToSplanchnic);
  m_pAortaToSpleen = m_CirculatoryCircuit->GetPath(pulse::CardiovascularPath::Aorta1ToSpleen);

  m_pBrainResistanceDownstream = m_CirculatoryCircuit->GetPath(pulse::CardiovascularPath::Brain1ToBrain2);
  m_pBrainResistanceUpstream = m_CirculatoryCircuit->GetPath(pulse::CardiovascularPath::Aorta1ToBrain1);

  m_pGndToAbdominalCavity = m_CirculatoryCircuit->GetPath(pulse::CardiovascularPath::GroundToAbdominalCavity1);
  m_pAbdominalCavityToGnd = m_CirculatoryCircuit->GetPath(pulse::CardiovascularPath::AbdominalCavity1ToGround);

  m_pGndToPericardium = m_CirculatoryCircuit->GetPath(pulse::CardiovascularPath::GroundToPericardium1);
  m_pPericardiumToGnd = m_CirculatoryCircuit->GetPath(pulse::CardiovascularPath::Pericardium1ToGround);
  m_pRightHeartToGnd = m_CirculatoryCircuit->GetPath(pulse::CardiovascularPath::RightHeart3ToGround);
  m_pRightHeart = m_CirculatoryCircuit->GetPath(pulse::CardiovascularPath::RightHeart1ToRightHeart3);
  m_pLeftHeartToGnd = m_CirculatoryCircuit->GetPath(pulse::CardiovascularPath::LeftHeart3ToGround);
  m_pLeftHeart = m_CirculatoryCircuit->GetPath(pulse::CardiovascularPath::LeftHeart1ToLeftHeart3);
  m_LeftHeartToAorta = m_CirculatoryCircuit->GetPath(pulse::CardiovascularPath::LeftHeart1ToAorta2);

  /// \todo We are assuming that the complex renal system is connected. Make it agnostic.
  m_leftRenalArteryPath = m_CirculatoryCircuit->GetPath(pulse::RenalPath::LeftRenalArteryToAfferentArteriole);
  m_rightRenalArteryPath = m_CirculatoryCircuit->GetPath(pulse::RenalPath::RightRenalArteryToAfferentArteriole);

  m_systemicResistancePaths.clear();
  m_systemicCompliancePaths.clear();
  std::vector<SEFluidCircuitNode*> venousNodes;
  SEFluidCircuitNode* aorta = m_CirculatoryCircuit->GetNode(pulse::CardiovascularNode::Aorta1);
  for (SEFluidCircuitPath* path : m_CirculatoryCircuit->GetPaths())
  {
    if (&path->GetSourceNode() == aorta && path->HasResistanceBaseline())
    {
      m_systemicResistancePaths.push_back(path);
      venousNodes.push_back(&path->GetTargetNode());
    }
  }
  for (SEFluidCircuitPath* path : m_CirculatoryCircuit->GetPaths())
  {
    for (SEFluidCircuitNode* node : venousNodes)
    {
      if (&path->GetSourceNode() == node)
      {
        if (path->HasResistanceBaseline())
          m_systemicResistancePaths.push_back(path);
        if (path->HasComplianceBaseline())
          m_systemicCompliancePaths.push_back(path);
        break;
      }
    }
  }
  // Add the portal vein!
  SEFluidCircuitPath* p = m_CirculatoryCircuit->GetPath(pulse::CardiovascularPath::PortalVeinToLiver1);
  if (!Contains(m_systemicResistancePaths, (*p)))
    m_systemicResistancePaths.push_back(p);
  m_AortaCompliance = m_CirculatoryCircuit->GetPath(pulse::CardiovascularPath::Aorta1ToAorta4);
  m_AortaResistance = m_CirculatoryCircuit->GetPath(pulse::CardiovascularPath::Aorta3ToAorta1);
  m_VenaCavaCompliance = m_CirculatoryCircuit->GetPath(pulse::CardiovascularPath::VenaCavaToGround);
  m_RightHeartResistance = m_CirculatoryCircuit->GetPath(pulse::CardiovascularPath::VenaCavaToRightHeart2);
}

//--------------------------------------------------------------------------------------------------
/// \brief
/// Cardiovascular system at steady state
///
/// \details
/// Initializes Cardiovascular conditions if any are present.
///  <UL>
///   <LI>Anemia</LI>
///   <LI>Renal Stenosis</LI>
///   <LI>Heart Failure</LI>
///   <LI>Pericardial Effusion</LI>
///  </UL>
///
//--------------------------------------------------------------------------------------------------
void Cardiovascular::AtSteadyState()
{
  m_data.GetCurrentPatient().GetHeartRateBaseline().Set(GetHeartRate());
  m_data.GetCurrentPatient().GetDiastolicArterialPressureBaseline().Set(GetDiastolicArterialPressure());
  m_data.GetCurrentPatient().GetSystolicArterialPressureBaseline().Set(GetSystolicArterialPressure());
  m_data.GetCurrentPatient().GetMeanArterialPressureBaseline().Set(GetMeanArterialPressure());

  std::string typeString = "Initial Stabilization Homeostasis: ";
  if (m_data.GetState() == EngineState::AtSecondaryStableState)
    typeString = "Secondary Stabilization Homeostasis: ";

  m_ss << typeString << "Patient heart rate = " << GetHeartRate();
  Info(m_ss);
  m_ss << typeString << "Patient diastolic arterial pressure = " << GetDiastolicArterialPressure();
  Info(m_ss);
  m_ss << typeString << "Patient systolic arterial pressure = " << GetSystolicArterialPressure();
  Info(m_ss);
  m_ss << typeString << "Patient mean arterial pressure = " << GetMeanArterialPressure();
  Info(m_ss);

  if (m_data.GetState() == EngineState::AtInitialStableState)
  {// At Resting State, apply conditions if we have them
    if (m_data.GetConditions().HasChronicAnemia())
      ChronicAnemia();
    if (m_data.GetConditions().HasChronicRenalStenosis())
      ChronicRenalStenosis();
    if (m_data.GetConditions().HasChronicVentricularSystolicDysfunction())
      ChronicHeartFailure();
    if (m_data.GetConditions().HasChronicPericardialEffusion())
      ChronicPericardialEffusion();
  }

  m_LeftHeartElastanceMax_mmHg_Per_mL = m_data.GetConfiguration().GetLeftHeartElastanceMaximum(PressurePerVolumeUnit::mmHg_Per_mL);
  m_RightHeartElastanceMax_mmHg_Per_mL = m_data.GetConfiguration().GetRightHeartElastanceMaximum(PressurePerVolumeUnit::mmHg_Per_mL);
}

//--------------------------------------------------------------------------------------------------
/// \brief
/// Establishes the anemia condition by removing hemoglobin and reducing blood viscosity (simulated by vascular resistance reduction).
///
/// \details
/// We are modeling iron deficiency anemia as a chronic reduction in hemoglobin in the blood as well as
/// a reduction in the cardiovascular resistances to lower the systemic vascular resistance that is
/// seen with the reduced viscosity. The oxygen carrying capacity of the blood is reduced due to the
/// decrease in hemoglobin content.
//--------------------------------------------------------------------------------------------------
void Cardiovascular::ChronicAnemia()
{
  SEChronicAnemia* anemia = m_data.GetConditions().GetChronicAnemia();
  double rf = anemia->GetReductionFactor().GetValue();

  // Maximum 30% reduction
  if (rf > 0.3)
  {
    /// \error if too much hemoglobin is removed, we will no longer meet validation, so set to maximum amount that can be removed.
    Error("Cannot remove more than 30% of hemoglobin in anemia in the Pulse Engine. Setting value to 30% and continuing.", "Cardiovascular::Anemia");
    rf = 0.3;
  }
  // Empirical resistance modification
  double viscousModifier = 1.0 - (0.15*rf);

  std::vector<SESubstance*> hemoglobinSubs;
  hemoglobinSubs.push_back(&m_data.GetSubstances().GetHb());
  hemoglobinSubs.push_back(&m_data.GetSubstances().GetHbO2());
  hemoglobinSubs.push_back(&m_data.GetSubstances().GetHbCO2());
  hemoglobinSubs.push_back(&m_data.GetSubstances().GetHbO2CO2());

  double newMass_g;
  SELiquidSubstanceQuantity* subQ;
  // Reduce all hemoglobin mass in all compartments
  for (SELiquidCompartment* cmpt : m_data.GetCompartments().GetVascularLeafCompartments())
  {
    if (!cmpt->HasVolume())
      continue;

    for (SESubstance* subst : hemoglobinSubs)
    {
      subQ = cmpt->GetSubstanceQuantity(*subst);
      newMass_g = subQ->GetMass(MassUnit::g)*(1 - rf);
      subQ->GetMass().SetValue(newMass_g, MassUnit::g);
      subQ->Balance(BalanceLiquidBy::Mass);
    }
  }

  // Only the cardiovascular paths are adjusted. This is obviously an inconsistency, but 
  // other vascular paths may contain non-blood fluids for which viscosity is unaffected by
  // anemia. This gets us close enough.
  for (SEFluidCircuitPath* path : m_data.GetCircuits().GetCardiovascularCircuit().GetPaths())
  {
    if (path->HasResistanceBaseline())
    {
    path->GetResistanceBaseline().SetValue(path->GetResistanceBaseline(PressureTimePerVolumeUnit::mmHg_s_Per_mL)*viscousModifier, PressureTimePerVolumeUnit::mmHg_s_Per_mL);
    }   
  }
}

//--------------------------------------------------------------------------------------------------
/// \brief
/// Establishes the chronic heart failure condition.
///
/// \details
/// Heart failure is a chronic condition that is modeled by a permanent
/// reduction in the left heart contractility. The user may scale the severity of this action
/// with a fraction from 0 to 1, with 0 being non-existent to 1 being severe heart failure.
//--------------------------------------------------------------------------------------------------
void Cardiovascular::ChronicHeartFailure()
{
  //Decrease left heart contractility
  m_LeftHeartElastanceModifier = 0.27;
}

//--------------------------------------------------------------------------------------------------
/// \brief
/// Establishes the pericardial effusion condition.
///
/// \details
/// Pericardial effusion can be either chronic (slow) or acute (fast).
/// Chronic effusion will eventually lead to tamponade, acute effusion leads
/// immediately to tamponade and imminent death. The chronic effusion parameters 
/// are set in the Pulse engine so that life-threatening tamponade will occur 
///  in about 30 minutes after the insult.
//--------------------------------------------------------------------------------------------------
void Cardiovascular::ChronicPericardialEffusion()
{
  double deltaVolume_mL = m_data.GetConditions().GetChronicPericardialEffusion()->GetAccumulatedVolume().GetValue(VolumeUnit::mL);
  if (deltaVolume_mL > 1000.0)
  {
    Error("Cannot specify volume accumulation greater than 1000 mL. Accumulated volume is now set at 1000 mL.");
    /// \error Cannot specify volume accumulation greater than 1000 mL. Accumulated volume is now set at 1000 mL.
    deltaVolume_mL = 1000.0;
  }
  else if (deltaVolume_mL < 0.0)
  {
    Error("Cannot specify volume accumulation less than 0 mL. Accumulated volume is now set at 0 mL.");
    /// \error Cannot specify volume accumulation less than 0 mL. Accumulated volume is now set at 0 mL.
    deltaVolume_mL = 0.0;
  }

  //Just throw this all on at once
  //Only do this for a single time-step!
  m_pGndToPericardium->GetNextFlowSource().SetValue(deltaVolume_mL / m_dT_s, VolumePerTimeUnit::mL_Per_s);
}

//--------------------------------------------------------------------------------------------------
/// \brief
/// Establishes the renal stenosis condition in one or both of the renal arteries.
///
/// \details
/// Stenosed renal arteries are slightly occluded, which increases the resistance from the aorta to the kidney.
/// This is implemented as a condition, which specifies what percent of the artery is occluded and which artery
/// or arteries are being affected. 
//--------------------------------------------------------------------------------------------------
void Cardiovascular::ChronicRenalStenosis()
{
  ///\todo move this to CV
  double LeftOcclusionFraction = m_data.GetConditions().GetChronicRenalStenosis()->GetLeftKidneySeverity().GetValue();
  double RightOcclusionFraction = m_data.GetConditions().GetChronicRenalStenosis()->GetRightKidneySeverity().GetValue();

  if (LeftOcclusionFraction < 0.0)
  {
    /// \error Cannot specify left occlusion fraction less than zero
    Error("Cannot specify left occlusion fraction less than zero. Renal resistances remain unchanged."); //Specify resistance is the same in error
    return;
  }

  if (RightOcclusionFraction < 0.0)
  {
    /// \error Cannot specify right occlusion fraction less than zero
    Error("Cannot specify right occlusion fraction less than zero. Renal resistances remain unchanged.");
    return;
  }

  if (LeftOcclusionFraction > 1.0)
  {
    /// \error Cannot specify left occlusion fraction greater than one
    Error("Cannot specify left occlusion fraction greater than one. Renal resistances remain unchanged.");
    return;
  }

  if (RightOcclusionFraction > 1.0)
  {
    /// \error Cannot specify right occlusion fraction greater than one
    Error("Cannot specify right occlusion fraction greater than  one. Renal resistances remain unchanged.");
    return;
  }

  //Aorta1ToAfferentArteriole paths are equivalent to the renal artery in Pulse. Resistance increases on these paths to represent renal arterial stenosis
  double currentLeftResistance_mmHg_s_Per_mL = m_leftRenalArteryPath->GetResistanceBaseline(PressureTimePerVolumeUnit::mmHg_s_Per_mL);
  double currentRightResistance_mmHg_s_Per_mL = m_rightRenalArteryPath->GetResistanceBaseline(PressureTimePerVolumeUnit::mmHg_s_Per_mL);

  //The base resistance is a tuned parameter that allows for adequate flow reduction to the kidneys with the logarithmic functional form chosen
  double baseResistance_mmHg_s_Per_mL = 10.0;
  //Open resistance indicates a completely occluded artery. This value is 100 mmHg/mL/s for the cardiovascular circuit.
  double openResistance_mmHg_s_Per_mL = m_data.GetConfiguration().GetCardiovascularOpenResistance(PressureTimePerVolumeUnit::mmHg_s_Per_mL);

  double newLeftResistance_mmHg_s_Per_mL = GeneralMath::ExponentialDecayFunction(baseResistance_mmHg_s_Per_mL, openResistance_mmHg_s_Per_mL, currentLeftResistance_mmHg_s_Per_mL, LeftOcclusionFraction);
  double newRightResistance_mmHg_s_Per_mL = GeneralMath::ExponentialDecayFunction(baseResistance_mmHg_s_Per_mL, openResistance_mmHg_s_Per_mL, currentRightResistance_mmHg_s_Per_mL, RightOcclusionFraction);

  m_leftRenalArteryPath->GetResistanceBaseline().SetValue(newLeftResistance_mmHg_s_Per_mL, PressureTimePerVolumeUnit::mmHg_s_Per_mL);
  m_rightRenalArteryPath->GetResistanceBaseline().SetValue(newRightResistance_mmHg_s_Per_mL, PressureTimePerVolumeUnit::mmHg_s_Per_mL);
}

//--------------------------------------------------------------------------------------------------
/// \brief
/// Preprocess prepares the cardiovascular system for the circuit solver
///
/// \details
/// This function calculates the appropriate modifications to the cardiovascular
/// circuit for the time within the cardiac cycle and it processes the actions on the 
/// cardiovascular system.
//--------------------------------------------------------------------------------------------------
void Cardiovascular::PreProcess()
{
  // Locate the cardiac cycle in time (systole, diastole)
  // and do the appropriate calculations based on the time location.
  HeartDriver();
  ProcessActions();
  UpdateHeartRhythm();
  CalculatePleuralCavityVenousEffects();
}

//--------------------------------------------------------------------------------------------------
/// \brief
/// Process solves the cardiovascular circuit
///
/// \details
/// Modifications to the cardiovascular system are made during the preprocess
/// step of the cardiovascular and other systems. The new state of the circuit 
/// is solved using %Pulse @ref CircuitMethodology. Advective substance transport
/// is computed using the %Pulse @ref SubstanceTransportMethodology.
/// Finally, vitals sign data is computed and system data is populated in the 
/// CalculateVitalSigns method.
//--------------------------------------------------------------------------------------------------
void Cardiovascular::Process(bool solve_and_transport)
{
  if (solve_and_transport)
  {
    m_circuitCalculator->Process(*m_CirculatoryCircuit, m_dT_s);
    m_transporter->Transport(*m_CirculatoryGraph, m_dT_s);
  }
  CalculateVitalSigns();
  ComputeExposedModelParameters();
}
void Cardiovascular::ComputeExposedModelParameters()
{

}

//--------------------------------------------------------------------------------------------------
/// \brief
/// Update the cardiovascular circuit
///
/// \details
/// The current time-step's circuit solution is set to the next time-step when it is passed to PostProcess.
//--------------------------------------------------------------------------------------------------
void Cardiovascular::PostProcess(bool solve_and_transport)
{
  if(solve_and_transport)
    m_circuitCalculator->PostProcess(*m_CirculatoryCircuit);
}

//--------------------------------------------------------------------------------------------------
/// \brief
/// CalculateVitalSigns computes and/or updates cardiovascular system level data
///
/// \details
/// Calculate vital signs obtains the pressures in the aorta, pulmonary arteries, pulmonary veins and vena cava. 
/// Waveform data for the system, such as arterial pressure, is set every at every time slice. Mean data, such
/// as mean arterial pressure, is set using a running average. Data that are more useful filtered are also set
/// from a running mean. 
/// Several events and irreversible states are detected and set by this method.
//--------------------------------------------------------------------------------------------------
void Cardiovascular::CalculateVitalSigns()
{
  // Grab data from the circuit in order to calculate a running mean
  double AortaNodePressure_mmHg = m_Aorta->GetPressure(PressureUnit::mmHg);
  double AortaNodeCO2PartialPressure_mmHg = m_AortaCO2 == nullptr ? 0 : m_AortaCO2->GetPartialPressure(PressureUnit::mmHg); // This is here so we can Tune circuit w/o substances
  double LeftPulmonaryArteryVolume_mL = m_LeftPulmonaryArteries->GetVolume(VolumeUnit::mL);
  double RightPulmonaryArteryVolume_mL = m_RightPulmonaryArteries->GetVolume(VolumeUnit::mL);
  double TotalPulmonaryArteryVolume_mL = LeftPulmonaryArteryVolume_mL + RightPulmonaryArteryVolume_mL;
  double LeftPulmonaryArteryPressure_mmHg = m_LeftPulmonaryArteries->GetPressure(PressureUnit::mmHg);
  double RightPulmonaryArteryPressure_mmHg = m_RightPulmonaryArteries->GetPressure(PressureUnit::mmHg);

  double LeftPulmonaryVeinVolume_mL = m_LeftPulmonaryVeins->GetVolume(VolumeUnit::mL);
  double RightPulmonaryVeinVolume_mL = m_RightPulmonaryVeins->GetVolume(VolumeUnit::mL);
  double TotalPulmonaryVeinVolume_mL = LeftPulmonaryVeinVolume_mL + RightPulmonaryVeinVolume_mL;
  double LeftPulmonaryVeinPressure_mmHg = m_LeftPulmonaryVeins->GetPressure(PressureUnit::mmHg);
  double RightPulmonaryVeinPressure_mmHg = m_RightPulmonaryVeins->GetPressure(PressureUnit::mmHg);

  double PulmonaryArteryNodePressure_mmHg = (LeftPulmonaryArteryVolume_mL*LeftPulmonaryArteryPressure_mmHg + RightPulmonaryArteryVolume_mL*RightPulmonaryArteryPressure_mmHg) / TotalPulmonaryArteryVolume_mL;
  double PulmVeinNodePressure_mmHg = (LeftPulmonaryVeinVolume_mL*LeftPulmonaryVeinPressure_mmHg + RightPulmonaryVeinVolume_mL*RightPulmonaryVeinPressure_mmHg) / TotalPulmonaryVeinVolume_mL;
  double PulmCapFlow_mL_Per_s = m_LeftPulmonaryArteriesToCapillaries->GetNextFlow(VolumePerTimeUnit::mL_Per_s)
    + m_RightPulmonaryArteriesToCapillaries->GetNextFlow(VolumePerTimeUnit::mL_Per_s);
  double PulmShuntFlow_mL_Per_s = m_LeftPulmonaryArteriesToVeins->GetNextFlow(VolumePerTimeUnit::mL_Per_s)
    + m_RightPulmonaryArteriesToVeins->GetNextFlow(VolumePerTimeUnit::mL_Per_s);

  double VenaCavaPressure_mmHg = m_VenaCava->GetPressure(PressureUnit::mmHg);

  double SkinFlow_mL_Per_s = m_pAortaToSkin->GetNextFlow(VolumePerTimeUnit::mL_Per_s);
  double LHeartFlow_mL_Per_s = m_LeftHeartToAorta->GetNextFlow(VolumePerTimeUnit::mL_Per_s);
  double LHeartVolume_mL = m_LeftHeart->GetVolume(VolumeUnit::mL);

  double muscleFlow_mL_Per_s = m_pAortaToMuscle->GetNextFlow(VolumePerTimeUnit::mL_Per_s);

  double gutFlow_mL_Per_s = m_pAortaToLargeIntestine->GetNextFlow(VolumePerTimeUnit::mL_Per_s) +
    m_pAortaToSmallIntestine->GetNextFlow(VolumePerTimeUnit::mL_Per_s) +
    m_pAortaToSplanchnic->GetNextFlow(VolumePerTimeUnit::mL_Per_s);

  // Calculate heart rate - Threshold of 0.1 is empirically determined. Approximate zero makes it too noisy.
  m_CurrentCardiacCycleDuration_s += m_dT_s;
  if (LHeartFlow_mL_Per_s > 0.1 && !m_HeartFlowDetected)
  {
    m_HeartFlowDetected = true;
    CalculateHeartRate();
    RecordAndResetCardiacCycle();
  }
  if (LHeartFlow_mL_Per_s < 0.1 && m_HeartFlowDetected)
    m_HeartFlowDetected = false;

  // Record high and low values to compute for systolic and diastolic pressures:
  if (AortaNodePressure_mmHg > m_CardiacCycleAortaPressureHigh_mmHg)
    m_CardiacCycleAortaPressureHigh_mmHg = AortaNodePressure_mmHg;  
  if (AortaNodePressure_mmHg < m_CardiacCycleAortaPressureLow_mmHg)
    m_CardiacCycleAortaPressureLow_mmHg = AortaNodePressure_mmHg;  
  if (PulmonaryArteryNodePressure_mmHg > m_CardiacCyclePulmonaryArteryPressureHigh_mmHg)
    m_CardiacCyclePulmonaryArteryPressureHigh_mmHg = PulmonaryArteryNodePressure_mmHg;
  if (PulmonaryArteryNodePressure_mmHg < m_CardiacCyclePulmonaryArteryPressureLow_mmHg)
    m_CardiacCyclePulmonaryArteryPressureLow_mmHg = PulmonaryArteryNodePressure_mmHg;

  // Get Max of Left Ventricle Volume over the course of a heart beat for end diastolic volume
  if (LHeartVolume_mL > m_CardiacCycleDiastolicVolume_mL)
    m_CardiacCycleDiastolicVolume_mL = LHeartVolume_mL;

  // Increment stroke volume. Get samples for running means
  m_CardiacCycleStrokeVolume_mL += LHeartFlow_mL_Per_s*m_dT_s;
  m_CardiacCycleArterialPressure_mmHg->Sample(AortaNodePressure_mmHg);
  m_CardiacCycleArterialCO2PartialPressure_mmHg->Sample(AortaNodeCO2PartialPressure_mmHg);
  m_CardiacCyclePulmonaryCapillariesWedgePressure_mmHg->Sample(PulmVeinNodePressure_mmHg);
  m_CardiacCyclePulmonaryCapillariesFlow_mL_Per_s->Sample(PulmCapFlow_mL_Per_s);
  m_CardiacCyclePulmonaryShuntFlow_mL_Per_s->Sample(PulmShuntFlow_mL_Per_s);
  m_CardiacCyclePulmonaryArteryPressure_mmHg->Sample(PulmonaryArteryNodePressure_mmHg);
  m_CardiacCycleCentralVenousPressure_mmHg->Sample(VenaCavaPressure_mmHg);
  m_CardiacCycleSkinFlow_mL_Per_s->Sample(SkinFlow_mL_Per_s);

  /// \todo Make sure irreversible state is hit before we get here.
  if (m_CardiacCycleAortaPressureLow_mmHg < -2.0)
  {
    Fatal("Diastolic pressure has fallen below zero.");
    /// \error Fatal: Diastolic pressure has fallen below -2
  }
  if (m_CardiacCycleAortaPressureHigh_mmHg > 700.0)
  {
    Fatal("Systolic pressure has exceeded physiologic range.");
    /// \error Fatal: Systolic pressure has exceeded 700
  }

  // Pressures\Flows from circuit
  GetArterialPressure().SetValue(AortaNodePressure_mmHg, PressureUnit::mmHg);
  GetPulmonaryArterialPressure().SetValue(PulmonaryArteryNodePressure_mmHg, PressureUnit::mmHg);
  GetCentralVenousPressure().SetValue(VenaCavaPressure_mmHg, PressureUnit::mmHg);
  GetCerebralBloodFlow().Set(m_Brain->GetInFlow());
  GetIntracranialPressure().Set(m_Brain->GetPressure());
  GetCerebralPerfusionPressure().SetValue(GetMeanArterialPressure(PressureUnit::mmHg) - GetIntracranialPressure(PressureUnit::mmHg), PressureUnit::mmHg);

  if (m_data.GetState() > EngineState::InitialStabilization)
  {// Don't throw events if we are initializing

  // Check for hypovolemic shock
  /// \event Patient: Hypovolemic Shock: blood volume below 65% of its normal value
    if (GetBloodVolume().GetValue(VolumeUnit::mL) <= (m_data.GetConfiguration().GetMinimumBloodVolumeFraction()* m_data.GetCurrentPatient().GetBloodVolumeBaseline(VolumeUnit::mL)))
    {
      m_data.GetEvents().SetEvent(eEvent::HypovolemicShock, true, m_data.GetSimulationTime());

      /// \event Patient: blood loss below 50%, irreversible state enacted 
      // @cite Gutierrez2004HemorrhagicShock
      double hypovolemicShock = 0.5*m_data.GetCurrentPatient().GetBloodVolumeBaseline(VolumeUnit::mL);
      if (GetBloodVolume().GetValue(VolumeUnit::mL) <= hypovolemicShock)
      {
        m_ss << "Over half the patients blood volume has been lost. The patient is now in an irreversible state.";
        Warning(m_ss);
        /// \irreversible Over half the patients blood volume has been lost.
        m_data.GetEvents().SetEvent(eEvent::IrreversibleState, true, m_data.GetSimulationTime());
      }
    }
    else
    {
      m_data.GetEvents().SetEvent(eEvent::HypovolemicShock, false, m_data.GetSimulationTime());
    }

    //Check for cardiogenic shock
    if (GetCardiacIndex().GetValue(VolumePerTimeAreaUnit::L_Per_min_m2) < 2.2 &&
      GetSystolicArterialPressure(PressureUnit::mmHg) < 90.0 &&
      GetPulmonaryCapillariesWedgePressure(PressureUnit::mmHg) > 15.0)
    {
      /// \event Patient: Cardiogenic Shock: Cardiac Index has fallen below 2.2 L/min-m^2, Systolic Arterial Pressure is below 90 mmHg, and Pulmonary Capillary Wedge Pressure is above 15.0.
      /// \cite dhakam2008review
      m_data.GetEvents().SetEvent(eEvent::CardiogenicShock, true, m_data.GetSimulationTime());
    }
    else
    {
      m_data.GetEvents().SetEvent(eEvent::CardiogenicShock, false, m_data.GetSimulationTime());
    }

    //Check for Tachycardia, Bradycardia, and asystole
    /// \event Patient: Tachycardia: heart rate exceeds 100 beats per minute.  This state is alleviated if it decreases below 90.
    if (GetHeartRate().GetValue(FrequencyUnit::Per_min) < 90)
      m_data.GetEvents().SetEvent(eEvent::Tachycardia, false, m_data.GetSimulationTime());
    if (GetHeartRate().GetValue(FrequencyUnit::Per_min) > 100)
      m_data.GetEvents().SetEvent(eEvent::Tachycardia, true, m_data.GetSimulationTime());
    /// \event Patient: Bradycardia: heart rate falls below 60 beats per minute.  This state is alleviated if it increases above 65.
    if (GetHeartRate().GetValue(FrequencyUnit::Per_min) < 60)
      m_data.GetEvents().SetEvent(eEvent::Bradycardia, true, m_data.GetSimulationTime());
    if (GetHeartRate().GetValue(FrequencyUnit::Per_min) > 65)
      m_data.GetEvents().SetEvent(eEvent::Bradycardia, false, m_data.GetSimulationTime());
    if (GetHeartRate().GetValue(FrequencyUnit::Per_min) == 0 || m_data.GetActions().GetPatientActions().HasCardiacArrest())
    {
      m_data.GetEvents().SetEvent(eEvent::Asystole, true, m_data.GetSimulationTime());
    }
    else
    {
      m_data.GetEvents().SetEvent(eEvent::Asystole, false, m_data.GetSimulationTime());
    }
  }

  // Irreversible state if asystole persists.
  if (GetHeartRhythm() == eHeartRhythm::Asystolic)
  {
    /// \event Patient: Irreversible State: heart has been in asystole for over 45 min:
    if (m_data.GetEvents().GetEventDuration(eEvent::Asystole, TimeUnit::s) > 2700.0) // \cite: Zijlmans2002EpilepticSeizuresAsystole
    {
      m_ss << "Asystole has occurred for " << m_data.GetEvents().GetEventDuration(eEvent::Asystole, TimeUnit::s) << " seconds, patient is in irreversible state.";
      Warning(m_ss);
      /// \irreversible Heart has been in asystole for over 45 min
      m_data.GetEvents().SetEvent(eEvent::IrreversibleState, true, m_data.GetSimulationTime());
    }
  }

  // Compute blood volume
  double blood_mL = 0;
  for (SELiquidCompartment* cmpt : m_data.GetCompartments().GetVascularLeafCompartments())
  {
    if (cmpt->HasVolume() && cmpt != m_Pericardium) //Don't include pericardium
    {
      blood_mL += cmpt->GetVolume(VolumeUnit::mL);
    }
  }
  GetBloodVolume().SetValue(blood_mL, VolumeUnit::mL);
}

//--------------------------------------------------------------------------------------------------
/// \brief
/// Sets the systolic and diastolic pressures.
///
/// \details
/// The systemic arterial and pulmonary arterial systolic and diastolic pressures are set here. 
/// The variables used to track the maximum and minimum pressures are then reset for the next cardiac cycle.
//--------------------------------------------------------------------------------------------------
void Cardiovascular::RecordAndResetCardiacCycle()
{
  GetSystolicArterialPressure().SetValue(m_CardiacCycleAortaPressureHigh_mmHg, PressureUnit::mmHg);
  GetDiastolicArterialPressure().SetValue(m_CardiacCycleAortaPressureLow_mmHg, PressureUnit::mmHg);
  GetPulmonarySystolicArterialPressure().SetValue(m_CardiacCyclePulmonaryArteryPressureHigh_mmHg, PressureUnit::mmHg);
  GetPulmonaryDiastolicArterialPressure().SetValue(m_CardiacCyclePulmonaryArteryPressureLow_mmHg, PressureUnit::mmHg);
  GetPulsePressure().SetValue(m_CardiacCycleAortaPressureHigh_mmHg - m_CardiacCycleAortaPressureLow_mmHg, PressureUnit::mmHg);  

  m_data.GetCardiovascular().GetHeartStrokeVolume().SetValue(m_CardiacCycleStrokeVolume_mL, VolumeUnit::mL);
  double ejectionFraction = 0.;
  if (m_CardiacCycleDiastolicVolume_mL > ZERO_APPROX)
    ejectionFraction = m_CardiacCycleStrokeVolume_mL / m_CardiacCycleDiastolicVolume_mL;
  GetHeartEjectionFraction().SetValue(ejectionFraction);
  GetCardiacOutput().SetValue(m_CardiacCycleStrokeVolume_mL * GetHeartRate().GetValue(FrequencyUnit::Per_min), VolumePerTimeUnit::mL_Per_min);
  GetCardiacIndex().SetValue(GetCardiacOutput().GetValue(VolumePerTimeUnit::mL_Per_min) / m_data.GetCurrentPatient().GetSkinSurfaceArea(AreaUnit::m2), VolumePerTimeAreaUnit::mL_Per_min_m2);

  // Running means
  // Mean Arterial Pressure
  GetMeanArterialPressure().SetValue(m_CardiacCycleArterialPressure_mmHg->Value(), PressureUnit::mmHg);
  m_CardiacCycleArterialPressure_mmHg->Clear();
  // Mean Aterial CO2 Partial Pressure
  GetMeanArterialCarbonDioxidePartialPressure().SetValue(m_CardiacCycleArterialCO2PartialPressure_mmHg->Value(), PressureUnit::mmHg);
  // Mean Aterial CO2 Partial Pressure Delta
  GetMeanArterialCarbonDioxidePartialPressureDelta().SetValue(m_CardiacCycleArterialCO2PartialPressure_mmHg->Value() - m_LastCardiacCycleMeanArterialCO2PartialPressure_mmHg, PressureUnit::mmHg);
  m_LastCardiacCycleMeanArterialCO2PartialPressure_mmHg = m_CardiacCycleArterialCO2PartialPressure_mmHg->Value();
  m_CardiacCycleArterialCO2PartialPressure_mmHg->Clear();
  // Pulmonary Capillary Wedge Pressure
  GetPulmonaryCapillariesWedgePressure().SetValue(m_CardiacCyclePulmonaryCapillariesWedgePressure_mmHg->Value(), PressureUnit::mmHg);
  m_CardiacCyclePulmonaryCapillariesWedgePressure_mmHg->Clear();
  // Pulmonary Capillary Mean Flow
  GetPulmonaryMeanCapillaryFlow().SetValue(m_CardiacCyclePulmonaryCapillariesFlow_mL_Per_s->Value(), VolumePerTimeUnit::mL_Per_s);
  m_CardiacCyclePulmonaryCapillariesFlow_mL_Per_s->Clear();
  // Pulmonary Shunt Mean Flow
  GetPulmonaryMeanShuntFlow().SetValue(m_CardiacCyclePulmonaryShuntFlow_mL_Per_s->Value(), VolumePerTimeUnit::mL_Per_s);
  m_CardiacCyclePulmonaryShuntFlow_mL_Per_s->Clear();
  // Mean Pulmonary Artery Pressure
  GetPulmonaryMeanArterialPressure().SetValue(m_CardiacCyclePulmonaryArteryPressure_mmHg->Value(), PressureUnit::mmHg);
  m_CardiacCyclePulmonaryArteryPressure_mmHg->Clear();
  // Mean Central Venous Pressure
  GetMeanCentralVenousPressure().SetValue(m_CardiacCycleCentralVenousPressure_mmHg->Value(), PressureUnit::mmHg);
  m_CardiacCycleCentralVenousPressure_mmHg->Clear();
  // Mean Skin Flow
  GetMeanSkinFlow().SetValue(m_CardiacCycleSkinFlow_mL_Per_s->Value(), VolumePerTimeUnit::mL_Per_s);
  m_CardiacCycleSkinFlow_mL_Per_s->Clear();

  // Computed systemic Vascular Resistance
  double cardiacOutput_mL_Per_s = GetCardiacOutput().GetValue(VolumePerTimeUnit::mL_Per_s);
  double systemicVascularResistance_mmHg_s_Per_mL = 0.0;
  if (cardiacOutput_mL_Per_s > ZERO_APPROX)
    systemicVascularResistance_mmHg_s_Per_mL = (GetMeanArterialPressure().GetValue(PressureUnit::mmHg) - GetMeanCentralVenousPressure().GetValue(PressureUnit::mmHg)) / cardiacOutput_mL_Per_s;
  GetSystemicVascularResistance().SetValue(systemicVascularResistance_mmHg_s_Per_mL, PressureTimePerVolumeUnit::mmHg_s_Per_mL);

  // Computed pulmonary Vascular Resistances
  if (cardiacOutput_mL_Per_s == 0.0)
  {
    GetPulmonaryVascularResistance().SetValue(0.0, PressureTimePerVolumeUnit::mmHg_min_Per_mL);
    GetPulmonaryVascularResistanceIndex().SetValue(0.0, PressureTimePerVolumeAreaUnit::mmHg_min_Per_mL_m2);
  }
  else
  {
    //(Mean arteral pressure - mean pulmonary wedge pressure)/Cardiac output
    double PulmonaryPressureDrop_mmHg = GetPulmonaryMeanArterialPressure(PressureUnit::mmHg) - GetPulmonaryCapillariesWedgePressure(PressureUnit::mmHg);
    GetPulmonaryVascularResistance().SetValue(PulmonaryPressureDrop_mmHg / cardiacOutput_mL_Per_s, PressureTimePerVolumeUnit::mmHg_s_Per_mL);

    //Mean arteral pressure - mean pulmonary wedge pressure)/Cardiac index where cardiac index is cardiac output / body surface area
    GetPulmonaryVascularResistanceIndex().SetValue(PulmonaryPressureDrop_mmHg / GetCardiacIndex(VolumePerTimeAreaUnit::mL_Per_s_m2), PressureTimePerVolumeAreaUnit::mmHg_s_Per_mL_m2);
  }
  
  m_CardiacCycleAortaPressureHigh_mmHg = 0.0;
  m_CardiacCycleAortaPressureLow_mmHg = 10000.0;
  m_CardiacCyclePulmonaryArteryPressureHigh_mmHg = 0.0;
  m_CardiacCyclePulmonaryArteryPressureLow_mmHg = 10000.0;
  m_CardiacCycleDiastolicVolume_mL = 0;
  m_CardiacCycleStrokeVolume_mL = 0;
}

//--------------------------------------------------------------------------------------------------
/// \brief
/// Holds the action methods for the cardiovascular system.
///
/// \details
/// This method holds the actions for the CV system so that only one
/// method need be called in preprocess.
/// <ul>
///   <li> Hemorrhage </li>
///   <li> Pericardial Effusion </li>
///   <li> CPR </li>
///   <li> CardiacArrest </li>
/// </ul>
//--------------------------------------------------------------------------------------------------
void Cardiovascular::ProcessActions()
{
  TraumaticBrainInjury();
  Hemorrhage();
  PericardialEffusion();
  CPR();
  CardiacArrest();
}

//--------------------------------------------------------------------------------------------------
/// \brief
/// The traumatic brain injury action increases flow resistance in the brain
///
/// \details
/// The user may specify a brain injury of varying severity to apply during runtime. The brain resistance
/// is scaled based on severity, which impacts flow and pressure in the brain, simulating the effects of
/// a non-localized brain injury.
//--------------------------------------------------------------------------------------------------
void Cardiovascular::TraumaticBrainInjury()
{
  if (!m_data.GetActions().GetPatientActions().HasBrainInjury())
    return;

  //Grab info about the injury
  SEBrainInjury* b = m_data.GetActions().GetPatientActions().GetBrainInjury();
  double severity = b->GetSeverity().GetValue();

  //Interpolate linearly between multipliers of 1 (for severity of 0) to max (for severity of 1)
  //These multipliers are chosen to result in ICP > 25 mmHg and CBF < 1.8 mL/s
  double usMult = GeneralMath::LinearInterpolator(0, 1, 1, 4.775, severity);
  double dsMult = GeneralMath::LinearInterpolator(0, 1, 1, 30.409, severity);

  m_pBrainResistanceDownstream->GetNextResistance().SetValue(dsMult * m_pBrainResistanceDownstream->GetResistanceBaseline().GetValue(PressureTimePerVolumeUnit::mmHg_s_Per_mL), PressureTimePerVolumeUnit::mmHg_s_Per_mL);
  m_pBrainResistanceUpstream->GetNextResistance().SetValue(usMult * m_pBrainResistanceUpstream->GetResistanceBaseline().GetValue(PressureTimePerVolumeUnit::mmHg_s_Per_mL), PressureTimePerVolumeUnit::mmHg_s_Per_mL);
}

//--------------------------------------------------------------------------------------------------
/// \brief
/// The hemorrhage function simulates bleeding from a specified compartment
///
/// \details
/// The user may specify multiple bleeds across the anatomical compartments. The Model creates a 
/// separate bleeding path for each node in each anatomical compartment by volume-weighting the 
/// flow. Hemorrhage calls for a compartment that already contains a hemorrhage will be overwritten 
/// with the new value. Compartments can overlap.
//--------------------------------------------------------------------------------------------------
void Cardiovascular::Hemorrhage()
{
  /// \todo Enforce limits and remove fatal errors.

  //Set all hemorrhage flows to zero, so:
  // - We can increment for overlapping compartments
  // - We know to remove ones that are turned off
  for (unsigned int hIter = 0; hIter < m_HemorrhagePaths.size(); hIter++)
  {
    m_HemorrhagePaths.at(hIter)->GetNextFlowSource().SetValue(0.0, VolumePerTimeUnit::mL_Per_s);
  }

  SEHemorrhage* h;
  double TotalLossRate_mL_Per_s = 0.0;
  double internal_rate_mL_Per_s = 0.0;
  std::vector<SEHemorrhage*> invalid_hemorrhages;
  const std::map <std::string, SEHemorrhage*> & hems = m_data.GetActions().GetPatientActions().GetHemorrhages();
  for (auto hem : hems)
  {
    h = hem.second;
    double rate_mL_Per_s = h->GetRate().GetValue(VolumePerTimeUnit::mL_Per_s);
    // Allow shorthand naming
    SELiquidCompartment* compartment = m_data.GetCompartments().GetCardiovascularGraph().GetCompartment(h->GetCompartment());
    if (compartment == nullptr)
    {
      h->SetCompartment(h->GetCompartment() + "Vasculature");
      compartment = m_data.GetCompartments().GetCardiovascularGraph().GetCompartment(h->GetCompartment());
    }
    if (compartment == nullptr)
    {
      Error("Removing invalid Hemorrhage due to unsupported compartment : " + h->GetCompartment());
      invalid_hemorrhages.push_back(h);
      continue;
    }

    /// \error Error: Bleeding rate cannot be less than zero
    if (rate_mL_Per_s < 0)
    {
      m_ss << "Cannot specify bleeding less than 0";
      Error(m_ss);
      invalid_hemorrhages.push_back(h);
      continue;
    }
    /// \error Error: Bleeding must be from a vascular compartment
    if (!compartment)
    {
      m_ss << "Cannot hemorrhage from compartment "+h->GetComment()+", must be a valid vascular compartment";
      Error(m_ss);
      invalid_hemorrhages.push_back(h);
      continue;
    }
    if (h->GetType() == eHemorrhage_Type::Internal)
    {
      SELiquidCompartment* abdomenCompartment = m_data.GetCompartments().GetLiquidCompartment(pulse::VascularCompartment::Abdomen);
      if (!abdomenCompartment->HasChild(compartment->GetName()))
      {
        m_ss << "Internal Hemorrhage is only supported for the abdominal region, including the right and left kidneys, liver, spleen, splanchnic, and small and large intestine vascular compartments.";
        Error(m_ss);
        invalid_hemorrhages.push_back(h);
        continue;
      }
    }
    else //(h->GetType() == eHemorrhage_Type::External)
    {
      //Only mass is merely transfered if it is an internal bleed
      TotalLossRate_mL_Per_s += rate_mL_Per_s;
    }

    //Get all circuit nodes in this compartment
    std::vector<SEFluidCircuitNode*> nodes;
    nodes.insert(nodes.end(), compartment->GetNodeMapping().GetNodes().begin(), compartment->GetNodeMapping().GetNodes().end());
    for (unsigned int leafIter = 0; leafIter < compartment->GetLeaves().size(); leafIter++)
    {
      SELiquidCompartment* leaf = compartment->GetLeaves().at(leafIter);
      nodes.insert(nodes.end(), leaf->GetNodeMapping().GetNodes().begin(), leaf->GetNodeMapping().GetNodes().end());
    }

    unsigned int nodesIter = 0;
    unsigned int nodesWithVolume = 0;
    double totalVolume_mL = 0.0;
    while (nodesIter < nodes.size())
    {
      SEFluidCircuitNode* node = nodes.at(nodesIter);
      //Only use nodes that are part of the Circulatory circuit
      if (std::find(m_CirculatoryCircuit->GetNodes().begin(), m_CirculatoryCircuit->GetNodes().end(), node) == m_CirculatoryCircuit->GetNodes().end())
      {
        //Not in circuit
        nodes.erase(nodes.begin() + nodesIter);
        continue;
      }

      if (node->HasNextVolume())
      {
        nodesWithVolume++;
        totalVolume_mL += node->GetNextVolume(VolumeUnit::mL);
      }

      nodesIter++;
    }

    /// \error Fatal: Bleeding must come from nodes in the circultatory circuit
    if (nodes.size() == 0)
    {
      /// \error Error: Hemorrhage compartments must have nodes in the circulatory circuit
      m_ss << "Hemorrhage compartments must have nodes in the circulatory circuit";
      Error(m_ss);
      invalid_hemorrhages.push_back(h);
      continue;
    }

    //Update the circuit to remove blood from the specified compartment
    for (auto node : nodes)
    {
      //Weight the flow sink value by node volume
      double thisNodeRate_mL_Per_s = 0.0;
      if (nodesWithVolume == 0)
      {
        //No nodes have volume, so evenly distribute
        thisNodeRate_mL_Per_s = rate_mL_Per_s / double(nodes.size());
      }
      else if (!node->HasNextVolume())
      {
        //Some nodes have volume, but not this one, so move on
        continue;
      }
      else
      {
        //This node has volume
        thisNodeRate_mL_Per_s = rate_mL_Per_s * node->GetNextVolume(VolumeUnit::mL) / totalVolume_mL;
      }

      //Check if we've already been hemorrhaging here
      SEFluidCircuitPath* hemorrhagePath = nullptr;
      for (unsigned int hIter = 0; hIter < m_HemorrhagePaths.size(); hIter++)
      {
        hemorrhagePath = m_HemorrhagePaths.at(hIter);
        if (&(hemorrhagePath->GetSourceNode()) == node)
          break;
        hemorrhagePath = nullptr;
      }

      if (hemorrhagePath!=nullptr)
      {
        //Update the existing bleed path
        //Increment value to allow overlapping compartments
        hemorrhagePath->GetNextFlowSource().IncrementValue(thisNodeRate_mL_Per_s, VolumePerTimeUnit::mL_Per_s);
      }
      else
      {
        //Add bleed path for fluid mechanics
        SEFluidCircuitPath& newHemorrhagePath = m_CirculatoryCircuit->CreatePath(*node, *m_Ground, node->GetName() + "Hemorrhage");
        //Increment value to allow overlapping compartments
        newHemorrhagePath.GetNextFlowSource().IncrementValue(thisNodeRate_mL_Per_s, VolumePerTimeUnit::mL_Per_s);
        m_CirculatoryCircuit->StateChange();

        //Add bleed link for transport
        //Find the source compartment (may be a leaf) to make the graph work (i.e., to transport)
        SELiquidCompartment* sourceCompartment;
        if (std::find(compartment->GetNodeMapping().GetNodes().begin(), compartment->GetNodeMapping().GetNodes().end(), node) != compartment->GetNodeMapping().GetNodes().end())
        {
          sourceCompartment = compartment;
        }
        else
        {
          for (unsigned int leafIter = 0; leafIter < compartment->GetLeaves().size(); leafIter++)
          {
            SELiquidCompartment* leaf = compartment->GetLeaves().at(leafIter);
            if (std::find(leaf->GetNodeMapping().GetNodes().begin(), leaf->GetNodeMapping().GetNodes().end(), node) != leaf->GetNodeMapping().GetNodes().end())
            {
              sourceCompartment = leaf;
              break;
            }
          }
        }

        SELiquidCompartmentLink& newHemorrhageLink = m_data.GetCompartments().CreateLiquidLink(*sourceCompartment, *m_Groundcmpt, compartment->GetName() + "Hemorrhage");
        newHemorrhageLink.MapPath(newHemorrhagePath);
        m_CirculatoryGraph->AddLink(newHemorrhageLink);
        m_data.GetCompartments().StateChange();

        //Add to local lists
        m_HemorrhagePaths.push_back(&newHemorrhagePath);
        m_HemorrhageLinks.push_back(&newHemorrhageLink);
        if (h->GetType() == eHemorrhage_Type::Internal)
        {
          m_InternalHemorrhagePaths.push_back(&newHemorrhagePath);
          m_InternalHemorrhageLinks.push_back(&newHemorrhageLink);
        }
      }
    }

    //total the internal hemorrhage flow rate and apply it to the abdominal cavity path
    for (auto hemorrhage : m_InternalHemorrhagePaths)
    {
      internal_rate_mL_Per_s += hemorrhage->GetNextFlowSource().GetValue(VolumePerTimeUnit::mL_Per_s);
    }
    m_pGndToAbdominalCavity->GetNextFlowSource().SetValue(internal_rate_mL_Per_s, VolumePerTimeUnit::mL_Per_s);
  }

  // Remove any invalid hemorrhages
  for (SEHemorrhage* ih : invalid_hemorrhages)
    m_data.GetActions().GetPatientActions().RemoveHemorrhage(ih->GetCompartment());

  //Remove hemorrhage elements that aren't being used
  //Make sure to do this even if no hemorrhage action, since it's needed when removed
  unsigned int hIter = 0;
  while (hIter < m_HemorrhagePaths.size())
  {
    if (m_HemorrhagePaths.at(hIter)->GetNextFlowSource(VolumePerTimeUnit::mL_Per_s) == 0.0)
    {
      m_CirculatoryCircuit->RemovePath(*m_HemorrhagePaths.at(hIter));
      m_HemorrhagePaths.erase(m_HemorrhagePaths.begin() + hIter);
      m_CirculatoryCircuit->StateChange();

      m_CirculatoryGraph->RemoveLink(*m_HemorrhageLinks.at(hIter));
      m_HemorrhageLinks.erase(m_HemorrhageLinks.begin() + hIter);
      m_CirculatoryGraph->StateChange();

      continue;
    }
    hIter++;
  }

  //Update abdominal cavity compliance
  double abdominalBloodVolume = m_AbdominalCavity->GetVolume().GetValue(VolumeUnit::mL);
  double compliance_mL_Per_mmHg = 0;
  double complianceCurveExponent = 0.55;
  //Variable compliance calculation
  compliance_mL_Per_mmHg = pow(abdominalBloodVolume, complianceCurveExponent);
  m_pAbdominalCavityToGnd->GetComplianceBaseline().SetValue(compliance_mL_Per_mmHg, VolumePerPressureUnit::mL_Per_mmHg);

  //Effect the Aorta with internal hemorrhages
  InternalHemorrhagePressureApplication();

  if (TotalLossRate_mL_Per_s == 0)
    return;

  //Update the patient's mass
  double bloodDensity_kg_Per_mL = m_data.GetBloodChemistry().GetBloodDensity(MassPerVolumeUnit::kg_Per_mL);
  double massLost_kg = (TotalLossRate_mL_Per_s - internal_rate_mL_Per_s)*bloodDensity_kg_Per_mL*m_dT_s;
  double patientMass_kg = m_data.GetCurrentPatient().GetWeight(MassUnit::kg);
  patientMass_kg -= massLost_kg;

  m_data.GetCurrentPatient().GetWeight().SetValue(patientMass_kg, MassUnit::kg);
}

//--------------------------------------------------------------------------------------------------
/// \brief
/// The function initiates a flow source on the pericardium. It is used by both the action and condition.
///
/// \details
/// The pericardial effusion action may be called during run time. It initiates a flow source on the pericardium
/// which leads to increased pericardium volume. As the volume increases, a pressure source is applied to
/// the left and right heart nodes, simulating the restriction of the swelling pericardium.
//--------------------------------------------------------------------------------------------------
void Cardiovascular::PericardialEffusion()
{
  //We need to do this here because the circuit needs to be processed to modify the compliance pressure based on the volume change
  if ( m_data.GetConditions().HasChronicPericardialEffusion() &&
      !m_data.GetActions().GetPatientActions().HasPericardialEffusion())
  {
    PericardialEffusionPressureApplication();
  }

  if (!m_data.GetActions().GetPatientActions().HasPericardialEffusion())
    return;

  double complianceSlopeParameter = 0.0;
  double complianceCurveParameter = 0.0;
  double flowToPericardium_mL_per_s = 0.0;
  double flowCubed_mL3_Per_s3 = 0.0;
  double compliance_mL_Per_mmHg = 0.0;
  double intrapericardialVolume_mL = m_Pericardium->GetVolume(VolumeUnit::mL);
  double intrapericardialPressure_mmHg = m_Pericardium->GetPressure(PressureUnit::mmHg);

  double effusionRate_mL_Per_s = m_data.GetActions().GetPatientActions().GetPericardialEffusion()->GetEffusionRate().GetValue(VolumePerTimeUnit::mL_Per_s);
  if (effusionRate_mL_Per_s <= 0.1 && effusionRate_mL_Per_s > 0.0)
  {
    //Slow effusion
    complianceSlopeParameter = 0.4;
    complianceCurveParameter = 0.55;
  }
  else if (effusionRate_mL_Per_s > 0.1 && effusionRate_mL_Per_s < 1.0)
  {
    complianceSlopeParameter = 50;
    complianceCurveParameter = 0.1;
  }
  else if (effusionRate_mL_Per_s > 1.0)
  {
    Error("Effusion rate is out of physiologic bounds. Effusion rate is reset to 1.0 milliliters per second.");
    /// \error Effusion rate is out of physiologic bounds. Effusion rate is reset to 1.0 milliliters per second.
    effusionRate_mL_Per_s = 1.0;
    complianceSlopeParameter = 50;
    complianceCurveParameter = 0.1;
  }
  else if (effusionRate_mL_Per_s < 0.0)
  {
    Error("Cannot specify effusion rate less than zero. Effusion rate is now set to 0.0.");
    /// \error Cannot specify effusion rate less than zero. Effusion rate is now set to 0.0.
    effusionRate_mL_Per_s = 0.0;
    complianceSlopeParameter = 0.4;
    complianceCurveParameter = 0.55;
  }

  m_pGndToPericardium->GetNextFlowSource().SetValue(effusionRate_mL_Per_s, VolumePerTimeUnit::mL_Per_s);
  flowToPericardium_mL_per_s = m_pGndToPericardium->GetNextFlow(VolumePerTimeUnit::mL_Per_s);
  flowCubed_mL3_Per_s3 = flowToPericardium_mL_per_s*flowToPericardium_mL_per_s*flowToPericardium_mL_per_s;

  //Variable compliance calculation
  if (flowCubed_mL3_Per_s3 < 0.0001)
  {
    compliance_mL_Per_mmHg = m_pPericardiumToGnd->GetNextCompliance().GetValue(VolumePerPressureUnit::mL_Per_mmHg);
  }
  else
  {
    compliance_mL_Per_mmHg = complianceSlopeParameter / flowCubed_mL3_Per_s3 - complianceCurveParameter*intrapericardialVolume_mL;
  }

  m_pPericardiumToGnd->GetNextCompliance().SetValue(compliance_mL_Per_mmHg, VolumePerPressureUnit::mL_Per_mmHg);

  PericardialEffusionPressureApplication();
}

//--------------------------------------------------------------------------------------------------
/// \brief
/// The CPR function controls the force applied during a chest compression action.
///
/// \details
/// The user may apply a chest compression to continue blood circulation if the heart no longer has an effective rhythm.
/// The compression can either be defined by an explicit force or by a fraction of the maximum allowable force. 
/// If the compression input is a force scale then the method controls the shape of the force pulse and converts the force
/// pressure for application to the heart. 
/// If the compression input is force, then the raw force is converted to pressure and applied to
/// the heart. The pressure is applied at the pressure source on the LeftHeart3ToGround and 
/// RightHeart3ToGround paths in the cardiovascular circuit.
//--------------------------------------------------------------------------------------------------
void Cardiovascular::CPR()
{
  // If a compression has started, finish it.
  if (m_CompressionRatio > 0.0)
  {
    if (m_data.GetActions().GetPatientActions().HasChestCompressionForceScale()) 
    {
      Warning("Attempt to start a new compression during a previous compression. Allow more time between compressions or shorten the compression period.");
      m_data.GetActions().GetPatientActions().RemoveChestCompression();
      return;
    }

    if (m_data.GetActions().GetPatientActions().HasChestCompressionForce())
    {
      Warning("Attempt to switch to explicit force from force scale during CPR compression. CPR actions will be ignored until current compression ends.");
      m_data.GetActions().GetPatientActions().RemoveChestCompression();
      return;
    }

    CalculateAndSetCPRcompressionForce();
    return;
  }
  // If there is no chest compression action and we are not currently compressing, return to ProcessActions
  if (!m_data.GetActions().GetPatientActions().HasChestCompression())
    return;

  // Call for chest compression with an effective heart rhythm
  // In the future we may allow compressions on a beating heart, but that will require extensive testing
  // to evaluate the hemodynamic stability.
  if (!m_data.GetEvents().IsEventActive(eEvent::CardiacArrest))
  {
    Warning("CPR attempted on beating heart. Action ignored.");
    m_data.GetActions().GetPatientActions().RemoveChestCompression();
    return;
  }

  // Have a new call for a chest compression
  if (m_data.GetActions().GetPatientActions().HasChestCompressionForceScale())
  {
    m_CompressionRatio = m_data.GetActions().GetPatientActions().GetChestCompressionForceScale()->GetForceScale().GetValue();
    /// \error Warning: CPR compression ratio must be a positive value between 0 and 1 inclusive.
    if (m_CompressionRatio < 0.0)
      Warning("CPR compression ratio must be a positive value between 0 and 1 inclusive.");
    if (m_CompressionRatio > 1.0)
      Warning("CPR compression ratio must be a positive value between 0 and 1 inclusive.");

    BLIM(m_CompressionRatio, 0., 1.);
    // If no period was assigned by the user, then use the default - 0.4s
    if (m_data.GetActions().GetPatientActions().GetChestCompressionForceScale()->HasForcePeriod())
    {
      m_CompressionPeriod_s = m_data.GetActions().GetPatientActions().GetChestCompressionForceScale()->GetForcePeriod().GetValue(TimeUnit::s);
    }
    else
    {
      m_CompressionPeriod_s = 0.4;
    }

    m_data.GetActions().GetPatientActions().RemoveChestCompression();
  }

  CalculateAndSetCPRcompressionForce();
}

//--------------------------------------------------------------------------------------------------
/// \brief
/// Calculates and sets the pressure on the heart pressure sources when a CPR compression is applied.
///
/// \details
/// Calculates and sets the pressure on the heart pressure sources when a CPR compression is applied.
//--------------------------------------------------------------------------------------------------
void Cardiovascular::CalculateAndSetCPRcompressionForce()
{

  double compressionForce_N = 0.0;
  double compressionForceMax_N = 500.0;   // The maximum allowed compression force (corresponds to 1.0 when force scale is used)
  double compressionForceMin_N = 0.0;     // The minimum allowed compression force

  if (m_CompressionRatio > 0.0) //Force scale
  {
    // Bell curve shaping parameters
    double c = -10; // Defines the start and stop of the force bell curve given the period
    double a = 4 * c / (m_CompressionPeriod_s*m_CompressionPeriod_s);
    double b = -a*m_CompressionPeriod_s;

    compressionForce_N = pow(2, a*m_CompressionTime_s*m_CompressionTime_s + b*m_CompressionTime_s + c)*m_CompressionRatio*compressionForceMax_N;

    // 2 second max compression time is arbitrary. I just put it in to make sure it doesn't get stuck if
    // we accidentally make a really wide bell curve. Note that the bell curve parameters are currently hardcoded above.
    // If compression force has decayed to less than some amount or the time is above some amount, end the compression 
    if (m_CompressionTime_s > m_CompressionPeriod_s)
    {
      compressionForce_N = 0.0;
      m_CompressionTime_s = 0.0;
      m_CompressionRatio = 0.0;
      m_CompressionPeriod_s = 0.0;
    }
  }
  else //Explicit force
  {
    compressionForce_N = m_data.GetActions().GetPatientActions().GetChestCompressionForce()->GetForce().GetValue(ForceUnit::N);
  }

  m_CompressionTime_s += m_dT_s;

  if (compressionForce_N > compressionForceMax_N)
  {
    compressionForce_N = compressionForceMax_N;
    Warning("The compression force exceeded the maximum compression force. Compression force limited to 500N.");
  }

  if (compressionForce_N < compressionForceMin_N)
  {
    compressionForce_N = compressionForceMin_N;
    Warning("The compression force was less than the required minimum. Compression force limited to 0N.");
  }

  double leftHeartForceToPressureFactor = 0.1; // Tuning parameter to translate compression force in N to left heart pressure in mmHg
  double rightHeartForceToPressureFactor = 0.1; // Tuning parameter to translate compression force in N to right heart pressure in mmHg
  double nextLeftPressure_mmHg = leftHeartForceToPressureFactor*compressionForce_N;
  double nextRightPressure_mmHg = rightHeartForceToPressureFactor*compressionForce_N;

  m_pRightHeartToGnd->GetNextPressureSource().SetValue(nextRightPressure_mmHg, PressureUnit::mmHg);
  m_pLeftHeartToGnd->GetNextPressureSource().SetValue(nextLeftPressure_mmHg, PressureUnit::mmHg);

  // The action is removed when the force is set to 0.
  if (compressionForce_N == 0)
    m_data.GetActions().GetPatientActions().RemoveChestCompression();
}

//--------------------------------------------------------------------------------------------------
/// \brief
/// The cardiac arrest action causes the sudden loss of heart function and breathing.
///
/// \details
/// Cardiac arrest is the sudden loss of effective blood circulation. When the cardiac arrest
/// action is active, the heart will not beat effectively and breathing will not occur.
//--------------------------------------------------------------------------------------------------
void Cardiovascular::CardiacArrest()
{
  if (m_data.GetActions().GetPatientActions().HasCardiacArrest())
  {
    // Flip the cardiac arrest switch
    // This tells the CV system that a cardiac arrest has been initiated.
    // The cardiac arrest event will be triggered by CardiacCycleCalculations() at the end of the cardiac cycle.
    m_EnterCardiacArrest = true;
    //Force a new cardiac cycle to start when cardiac arrest is removed
    m_CurrentCardiacCycleTime_s = m_CardiacCyclePeriod_s - m_dT_s;
  }
  else
  {
    m_EnterCardiacArrest = false;
    m_data.GetEvents().SetEvent(eEvent::CardiacArrest, false, m_data.GetSimulationTime());
  }
}

//--------------------------------------------------------------------------------------------------
/// \brief
/// The pericardial effusion pressure application function calculates the pressure applied to the heart due to a pericardial effusion.
///
/// \details
/// The pressure applied to the left and right heart is dictated by the pericardium pressure. The response is tuned to 40% of this value
/// to achieve the correct physiologic response.
//--------------------------------------------------------------------------------------------------
void Cardiovascular::PericardialEffusionPressureApplication()
{
  double intrapericardialPressure_mmHg = m_Pericardium->GetPressure(PressureUnit::mmHg);

  double pressureResponseFraction = 0.4; //Tuning the pressure applied to the heart

  //Set the pressure on the right and left heart from the pericardium pressure
  m_pRightHeartToGnd->GetPressureSourceBaseline().SetValue(pressureResponseFraction*intrapericardialPressure_mmHg, PressureUnit::mmHg);
  m_pLeftHeartToGnd->GetPressureSourceBaseline().SetValue(pressureResponseFraction*intrapericardialPressure_mmHg, PressureUnit::mmHg);
}

//--------------------------------------------------------------------------------------------------
/// \brief
/// The internal pressure application function calculates the pressure applied to the aorta due to blood pooling in the abdominal cavity.
///
/// \details
/// The pressure applied to the aorta is dictated by the pressure in the abdominal cavity. The response is tuned to 45% of this value
/// to achieve the correct physiologic response.
//--------------------------------------------------------------------------------------------------
void Cardiovascular::InternalHemorrhagePressureApplication()
{
  double abdominalCavityPressure_mmHg = m_AbdominalCavity->GetPressure(PressureUnit::mmHg);

  double pressureResponseFraction = 5.0; //Tuning the pressure applied to the aorta

  //Set the pressure on the aorta based on the abdominal cavity pressure
  m_InternalHemorrhageToAorta->GetNextPressureSource().SetValue(pressureResponseFraction*abdominalCavityPressure_mmHg, PressureUnit::mmHg);

}

//--------------------------------------------------------------------------------------------------
/// \brief
/// Calculates the contraction and relaxation of the left and right heart during the cardiac cycle
///
/// \details
/// This function tracks the progress of the current cardiac cycle, and modifies the compliance of the left
/// and right heart to drive the cardiovascular circuit. The reduced compliance at the beginning of the cycle
/// acts to increase the pressure, driving flow out of the heart. The compliance is then reduced allowing flow into
/// the heart. This represents the systolic and diastolic portion of the cardiac cycle. The compliance is
/// driven by an elastance equation.
/// This function also keeps track of the cardiac cycle time and calls BeginCardiacCycle() at the start of
/// systole portion of each cycle. Modifications to heart rate and heart compliance are calculated by
/// BeginCardiacCycle() and applied for the remained of the current cardiac cycle. Changes to things like
/// heart rate and heart contractility can only occur at the top of the current cardiac cycle, after the last cardiac
/// cycle has completed. This helps to avoid discontinuous behavior such as the complete cessation of heart function
/// mid contraction.
//--------------------------------------------------------------------------------------------------
void Cardiovascular::HeartDriver()
{
  // Reset start cardiac cycle event if it was activated by BeginCardiacCycle() last time step
  if (m_data.GetEvents().IsEventActive(eEvent::StartOfCardiacCycle))
    m_data.GetEvents().SetEvent(eEvent::StartOfCardiacCycle, false, m_data.GetSimulationTime());

  // m_StartSystole is set to true at the end of a cardiac cycle in order to setup the next cardiac cycle.
  // After the next cycle is prepared in BeginCardiacCycle, m_StartSystole is seet back to false.
  if (m_StartSystole)
    BeginCardiacCycle();

  if (!m_data.GetEvents().IsEventActive(eEvent::CardiacArrest))
  {
    if (m_CurrentCardiacCycleTime_s >= m_CardiacCyclePeriod_s - m_dT_s)
      m_StartSystole = true; // A new cardiac cycle will begin next time step

    AdjustVascularTone();
    CalculateHeartElastance();
  }

  m_pRightHeart->GetNextCompliance().SetValue(1.0 / m_RightHeartElastance_mmHg_Per_mL, VolumePerPressureUnit::mL_Per_mmHg);
  m_pLeftHeart->GetNextCompliance().SetValue(1.0 / m_LeftHeartElastance_mmHg_Per_mL, VolumePerPressureUnit::mL_Per_mmHg);

  // Now that the math is done we can increment the cardiac cycle time
  // Note that the cardiac cycle time (m_CurrentCardiacCycleTime_s) continues to increment until a cardiac cycle begins (a beat happens)
  // So for a normal sinus rhythm, the maximum cardiac cycle time is equal to the cardiac cycle period (m_CardiacCyclePeriod_s).
  // For any ineffective rhythm (no heart beat) the cardiac cycle time will be as long as it has been since the last time there was an effective beat.
  m_CurrentCardiacCycleTime_s += m_dT_s;
}

//--------------------------------------------------------------------------------------------------
/// \brief
/// Sets up the evolution of the next cardiac cycle.
///
/// \details
/// This function is directed from Cardiovascular::HeartDriver. It set's up the evolution of the proceeding cardiac
/// cycle. It is used to apply the effects of drugs or exercise on the cardiovascular system. 
/// These effects will persist for the remainder of the cardiac cycle, at which point this function
/// is called again if a new heart beat is warranted (i.e. not in cardiac arrest).
//--------------------------------------------------------------------------------------------------
void Cardiovascular::BeginCardiacCycle()
{
  m_data.GetEvents().SetEvent(eEvent::StartOfCardiacCycle, true, m_data.GetSimulationTime());

  // Changes to the heart rate and other hemodynamic parameters are applied at the top of the cardiac cycle.
  // Parameters cannot change during the cardiac cycle because the heart beat is modeled as a changing compliance.

  // Apply baroreceptor reflex effects
  /// \todo need to reset the heart elastance min and max at the end of each stabiliation period in AtSteadyState()
  m_LeftHeartElastanceMax_mmHg_Per_mL = m_data.GetConfiguration().GetLeftHeartElastanceMaximum(PressurePerVolumeUnit::mmHg_Per_mL);
  if (m_data.GetNervous().HasBaroreceptorHeartElastanceScale())
    m_LeftHeartElastanceMax_mmHg_Per_mL *= m_data.GetNervous().GetBaroreceptorHeartElastanceScale().GetValue();

  m_RightHeartElastanceMax_mmHg_Per_mL = m_data.GetConfiguration().GetRightHeartElastanceMaximum(PressurePerVolumeUnit::mmHg_Per_mL);
  if (m_data.GetNervous().HasBaroreceptorHeartElastanceScale())
    m_RightHeartElastanceMax_mmHg_Per_mL *= m_data.GetNervous().GetBaroreceptorHeartElastanceScale().GetValue();

  double HeartDriverFrequency_Per_Min = m_data.GetCurrentPatient().GetHeartRateBaseline(FrequencyUnit::Per_min);
  if (m_data.GetNervous().HasBaroreceptorHeartRateScale())
    HeartDriverFrequency_Per_Min *= m_data.GetNervous().GetBaroreceptorHeartRateScale().GetValue();

  // Chemoreceptor and drug effects are deltas rather than multipliers, so they are added.
  // Apply chemoreceptor effects
  if (m_data.GetNervous().HasChemoreceptorHeartRateScale())
    HeartDriverFrequency_Per_Min += m_data.GetNervous().GetChemoreceptorHeartRateScale().GetValue();

  // Apply drug effects
  if (m_data.GetDrugs().HasHeartRateChange())
    HeartDriverFrequency_Per_Min += m_data.GetDrugs().GetHeartRateChange(FrequencyUnit::Per_min);
  BLIM(HeartDriverFrequency_Per_Min, m_data.GetCurrentPatient().GetHeartRateMinimum(FrequencyUnit::Per_min), m_data.GetCurrentPatient().GetHeartRateMaximum(FrequencyUnit::Per_min));

  //Apply heart failure effects
  m_LeftHeartElastanceMax_mmHg_Per_mL *= m_LeftHeartElastanceModifier;

  // Now set the cardiac cycle period and the cardiac arrest event if applicable
  if (m_EnterCardiacArrest)
  {
    m_data.GetEvents().SetEvent(eEvent::CardiacArrest, true, m_data.GetSimulationTime());
    m_CardiacCyclePeriod_s = 1.0e9; // Not beating, so set the period to a large number (1.0e9 sec = 31.7 years) 
    RecordAndResetCardiacCycle();
    GetHeartRate().SetValue(0.0, FrequencyUnit::Per_min);
  }
  else
  {
    if (HeartDriverFrequency_Per_Min == 0)
    {
      m_CardiacCyclePeriod_s = 5.0; // Can't divide by 0, but we want to check this again in a while to see if we can get out of asystole
      GetHeartRate().SetValue(0.0, FrequencyUnit::Per_min); // Will put patient into asystole
    }
    else
    {
      m_CardiacCyclePeriod_s = 60.0 / HeartDriverFrequency_Per_Min;
    }
  }

  // Reset the systole flag and the cardiac cycle time
  m_StartSystole = false;
  m_CurrentCardiacCycleTime_s = 0.0;
}


//--------------------------------------------------------------------------------------------------
/// \brief
/// Calculation of the left and right ventricular elastance
///
/// \details
/// This function calculates the left and right ventricular elastance at the current time in the cardiac cycle.
/// The elastance takes the form of a double hill function with a period equivalent to the cardiac cycle length.
/// \cite stergiopulos1996elastance
//--------------------------------------------------------------------------------------------------
void Cardiovascular::CalculateHeartElastance()
{
  //Shape parameters, used to define double hill functional form of the elastance
  double alpha1 = 0.303;
  double alpha2 = 0.508;
  double n1 = 1.32;
  double n2 = 21.9;
  double maxShape = 0.598;

  double normalizedCardiacTime = m_CurrentCardiacCycleTime_s / m_CardiacCyclePeriod_s;  
  double elastanceShapeFunction = (pow(normalizedCardiacTime / alpha1, n1) / (1.0 + pow(normalizedCardiacTime / alpha1, n1)))*(1.0 / (1.0 + pow(normalizedCardiacTime / alpha2, n2))) / maxShape;

  m_LeftHeartElastance_mmHg_Per_mL = (m_LeftHeartElastanceMax_mmHg_Per_mL - m_LeftHeartElastanceMin_mmHg_Per_mL)*elastanceShapeFunction + m_LeftHeartElastanceMin_mmHg_Per_mL;
  m_RightHeartElastance_mmHg_Per_mL = (m_RightHeartElastanceMax_mmHg_Per_mL - m_RightHeartElastanceMin_mmHg_Per_mL)*elastanceShapeFunction + m_RightHeartElastanceMin_mmHg_Per_mL;
}

//--------------------------------------------------------------------------------------------------
/// \brief
/// Calculates metabolic and thermal feedback on the systemic vascular tone
///
/// \details
/// This method controls the vascular tone response to metabolic changes. As the metabolic rate increases, 
/// the resistances to non-vital organs is increased while the resistance to the muscle and skin is reduced,
/// thus increasing heat convective rejection (see Energy::UpdateHeatResistance()). In the case of decreasing core temperature
/// the resistance to the skin is increased to shunt blood flow and reduce heat transfer from the core to skin.
//--------------------------------------------------------------------------------------------------
/// \todo Possibly add a thermoreception model to nervous and move the computation there.
void Cardiovascular::MetabolicToneResponse()
{
  double metabolicFraction = 1.0;
  if (m_data.GetEnergy().HasTotalMetabolicRate())
  {
    double TMR_kcal_Per_day = m_data.GetEnergy().GetTotalMetabolicRate(PowerUnit::kcal_Per_day);
    metabolicFraction = TMR_kcal_Per_day / m_data.GetCurrentPatient().GetBasalMetabolicRate(PowerUnit::kcal_Per_day);
  }
  
  if (metabolicFraction == 1.0)
    return;

  double coreTemp_degC = m_data.GetEnergy().GetCoreTemperature(TemperatureUnit::C); //Resting: 37.0 degC
  double coreTempSet_degC = m_data.GetConfiguration().GetCoreTemperatureHigh(TemperatureUnit::C); //37.1 degC
  double coreTempDelta_degC = MAX(coreTemp_degC - coreTempSet_degC, 0.0);
  coreTempDelta_degC = MIN(coreTempDelta_degC, 1.0); //A 1 degree increase in core temperature is the where the cardiovascular response on resistances is capped
  //The skin multiplier is used to increase the skin blood flow resistance, effectively reducing the skin blood flow leading to less heat transfered from core to skin.
  double skinMultiplier = 1.0 / MAX((coreTemp_degC - 35.0), 0.001);
  double coreTempLow_degC = m_data.GetConfiguration().GetCoreTemperatureLow(TemperatureUnit::C); //36.8 degC
  /// \cite talebipour2006sauna
  double tempMultiplier = 1.0 - 0.4*MIN(coreTempDelta_degC, 1.0); //Approximate 40% reduction in peripheral resistance due to core temperature rise of 1 degree.
  double metabolicModifier = 1.0;
  //The metabolic multiplier is used as a tuned response to represent cardiovascular resistance effects during exercise
  double sp0 = 1.5;
  double divisor = 7.0;
  double metabolicMultiplier = (sp0*metabolicFraction + (divisor - sp0)) / divisor;

  // Max delta approx. 20% of baseline \cite christie1997cardiac \cite foster1999left
  double metabolicRateMeanArterialPressureDelta_mmHg = (0.05*metabolicFraction - 0.05)*m_data.GetCurrentPatient().GetMeanArterialPressureBaseline(PressureUnit::mmHg);
  m_data.GetEnergy().GetExerciseMeanArterialPressureDelta().SetValue(metabolicRateMeanArterialPressureDelta_mmHg, PressureUnit::mmHg);

  //Reducing resistances scaling with metabolic rate increase and changes in core temperature
  double resistanceNew__mmHg_s_Per_mL = 0.0;
  double complianceNew_mL_Per_mmHg = 0.0;

  for (SEFluidCircuitPath* Path : m_systemicResistancePaths)
  {
    if (Path->HasResistanceBaseline())
    {
      if (Path == m_pAortaToMuscle || Path == m_pMuscleToVenaCava)
      { // Biggest change in muscle
        resistanceNew__mmHg_s_Per_mL = (1.0 / metabolicModifier)*(1.0 / metabolicModifier)*Path->GetNextResistance(PressureTimePerVolumeUnit::mmHg_s_Per_mL);
      }
      else if (Path == m_pAortaToBrain || Path == m_pAortaToMyocardium || Path == m_pBrainToVenaCava || Path == m_pMyocardiumToVenaCava)
      { // No Change in the brain or myocardium
        resistanceNew__mmHg_s_Per_mL = Path->GetNextResistance(PressureTimePerVolumeUnit::mmHg_s_Per_mL);
      }
      else
      { // Smaller change in the rest of the tissue paths
        resistanceNew__mmHg_s_Per_mL = (1.0 / metabolicModifier)*Path->GetNextResistance(PressureTimePerVolumeUnit::mmHg_s_Per_mL);
      }

      // Overall reduction in flow resistance in all paths to allow for increased cardiac output with a metabolic rate increase
      /// \todo Skip over Brain and Myocardium and add arms and legs
      resistanceNew__mmHg_s_Per_mL *= (1.0 / metabolicMultiplier);
      if (resistanceNew__mmHg_s_Per_mL < m_minIndividialSystemicResistance__mmHg_s_Per_mL)
      {
        resistanceNew__mmHg_s_Per_mL = m_minIndividialSystemicResistance__mmHg_s_Per_mL;
      }
      Path->GetNextResistance().SetValue(resistanceNew__mmHg_s_Per_mL, PressureTimePerVolumeUnit::mmHg_s_Per_mL);
    }
  }

}

//--------------------------------------------------------------------------------------------------
/// \brief
/// Tune the cardiovascular circuit during stabilization
///
/// \details
/// Tunes the resistors and capacitors associated with tissue compartments during stabilization to achieve the requested patient parameters
//--------------------------------------------------------------------------------------------------
void Cardiovascular::TuneCircuit()
{
  DataTrack     circuitTrk;
  std::ofstream circuitFile;

  bool success = false;
  double systolicTarget_mmHg = m_data.GetCurrentPatient().GetSystolicArterialPressureBaseline(PressureUnit::mmHg);
  double diastolicTarget_mmHg = m_data.GetCurrentPatient().GetDiastolicArterialPressureBaseline(PressureUnit::mmHg);
  double heartRateTarget_bpm = m_data.GetCurrentPatient().GetHeartRateBaseline(FrequencyUnit::Per_min);

  m_ss << "Tuning to patient parameters : HeartRate(bpm):" << heartRateTarget_bpm << " Systolic(mmHg):" << systolicTarget_mmHg << " Diastolic(mmHg):" << diastolicTarget_mmHg;
  Info(m_ss);

  // Tuning variables  
  double pressuretolerance = 0.01;
  double stabPercentTolerance = 0.25;
  double stabCheckTime_s = 15.0;
  double srGain = 0.01; //Systemic is sensitive
  double acGain1 = 0.06;//Gains are empirical
  double acGain2 = 0.02;//Gains are empirical
  double vrGain = 0.06; //Gains are empirical
  
  bool   stable;
  double map_mmHg = 0, tgt_map_mmHg=0;
  double systolic_mmHg = 0, tgt_systolic_mmHg=0;
  double diastolic_mmHg = 0, tgt_diastolic_mmHg=0;
  double cardiacOutput_mL_Per_min = 0, tgt_cardiacOutput_mL_Per_min=0;
  double meanCVP_mmHg = 0, tgt_meanCVP_mmHg=0;
  double blood_mL = 0, tgt_blood_mL=0;
  
  double time_s = 0;
  double timeStep_s = m_data.GetTimeStep().GetValue(TimeUnit::s);
  double stableTime_s;
  double maxTime_s = 2000;
  double maxConfigurations = 50;
  for (int i = 0; i < maxConfigurations; i++)
  {
    stable = false;
    stableTime_s = 0;
    while (!stable)
    {
      m_data.AdvanceCallback(-1);
      HeartDriver();
      m_circuitCalculator->Process(*m_CirculatoryCircuit, m_dT_s);
      CalculateVitalSigns();
      m_circuitCalculator->PostProcess(*m_CirculatoryCircuit);
      //return; //Skip stabelization for debugging

      map_mmHg = GetMeanArterialPressure(PressureUnit::mmHg);
      systolic_mmHg = GetSystolicArterialPressure(PressureUnit::mmHg);
      diastolic_mmHg = GetDiastolicArterialPressure(PressureUnit::mmHg);
      cardiacOutput_mL_Per_min = GetCardiacOutput(VolumePerTimeUnit::mL_Per_min);
      meanCVP_mmHg = GetMeanCentralVenousPressure(PressureUnit::mmHg);
      blood_mL = GetBloodVolume(VolumeUnit::mL);

      stableTime_s += timeStep_s;
      bool stableMAP = true;
      if (GeneralMath::PercentDifference(tgt_map_mmHg, map_mmHg) > stabPercentTolerance)
        { stableTime_s = 0; tgt_map_mmHg = map_mmHg; stableMAP = false;}
      bool stableSystolic = true;
      if (GeneralMath::PercentDifference(tgt_systolic_mmHg, systolic_mmHg) > stabPercentTolerance)
        { stableTime_s = 0; tgt_systolic_mmHg = systolic_mmHg; stableSystolic = false; }
      bool stableDiastolic = true;
      if (GeneralMath::PercentDifference(tgt_diastolic_mmHg, diastolic_mmHg) > stabPercentTolerance)
        { stableTime_s = 0; tgt_diastolic_mmHg = diastolic_mmHg; stableDiastolic = false; }
      bool stableCO = true;
      if (GeneralMath::PercentDifference(tgt_cardiacOutput_mL_Per_min, cardiacOutput_mL_Per_min) > stabPercentTolerance)
        { stableTime_s = 0; tgt_cardiacOutput_mL_Per_min = cardiacOutput_mL_Per_min; stableCO = false; }
      //bool stableMeanCVP = true;
      //if (GeneralMath::PercentDifference(tgt_meanCVP_mmHg, meanCVP_mmHg) > 0.25)
      //  { stableTime_s = 0; tgt_meanCVP_mmHg = meanCVP_mmHg; stableMeanCVP = false; }
      bool stableBloodVol = true;
      if (GeneralMath::PercentDifference(tgt_blood_mL, blood_mL) > stabPercentTolerance)
        { stableTime_s = 0; tgt_blood_mL = blood_mL; stableBloodVol = false; }

      if (stableTime_s > stabCheckTime_s)
      {
        stable = true;
        m_ss << "We are stable at " << time_s;
        Info(m_ss);
      }
      if (time_s > maxTime_s)
      {
        Error("Could not stabilize this configuration");
        break;
      }

      if (!m_TuningFile.empty())
      {
        circuitTrk.Track(time_s, *m_CirculatoryCircuit);
        circuitTrk.Track("MAP_mmHg", time_s, map_mmHg);
        circuitTrk.Track("Systolic_mmHg", time_s, systolic_mmHg);
        circuitTrk.Track("Diastolilc_mmHg", time_s, diastolic_mmHg);
        circuitTrk.Track("MeanCVP_mmHg", time_s, meanCVP_mmHg);
        circuitTrk.Track("CardiacOutput_mL_per_s", time_s, cardiacOutput_mL_Per_min);
        circuitTrk.Track("BloodVolume_mL", time_s, blood_mL);

        if (time_s == 0)
          circuitTrk.CreateFile(m_TuningFile.c_str(), circuitFile);
         circuitTrk.StreamTrackToFile(circuitFile);
      }
      time_s += m_dT_s;
    }
    if (!m_TuneCircuit)
    {
      Info("Not tuning circuit");
      success = true; // Assume this is what you want
      break;
    }

    double systolicError_mmHg = systolicTarget_mmHg - systolic_mmHg;
    double diastolicError_mmHg = diastolicTarget_mmHg - diastolic_mmHg;
    if (stable)
    {
      // Compute the pressure errors     
      if (std::abs(systolicError_mmHg / systolicTarget_mmHg) < pressuretolerance && std::abs(diastolicError_mmHg / diastolicTarget_mmHg) < pressuretolerance) //relative error check
      {
        success = true;
        break; // We met our patient parameters
      }
    }

    // This configuration did not meet the requests patient baselines, Tune the paths
    double systemicResistanceScale = 1;
    double systemicComplianceScale = 1;
    double aortaResistanceScale = 1;
    double aortaComplianceScale = 1;
    double rightHeartResistanceScale = 1;
    double venaCavaComplianceScale = 1;
    if ((systolicError_mmHg > 0 && diastolicError_mmHg > 0) || (systolicError_mmHg < 0 && diastolicError_mmHg < 0)) // Same direction
    {
      if (cardiacOutput_mL_Per_min > 4000.0)
      {
        systemicResistanceScale += srGain * (systolicError_mmHg + diastolicError_mmHg);
        BLIM(systemicResistanceScale, 0.5, 1.5);
      }
      else
      {
        rightHeartResistanceScale -= vrGain * (systolicError_mmHg + diastolicError_mmHg);
        systemicResistanceScale += srGain * (systolicError_mmHg + diastolicError_mmHg);
        BLIM(rightHeartResistanceScale, 0.5, 1.5);
        BLIM(systemicResistanceScale, 0.5, 1.5);
        Info("Using vena cava resistance gain.");
      }
    }
    else if ((systolicError_mmHg > 0 && diastolicError_mmHg < 0) || (systolicError_mmHg < 0 && diastolicError_mmHg > 0)) // Opposite directions
    {
      // Widen or narrow based on both errors
      if (meanCVP_mmHg < 2.0 || meanCVP_mmHg > 6.0) // Go ahead and do it but warn the user that CVP is out of normal range.
        Warning("We're out of CVP range");
      aortaComplianceScale -= acGain1 * systolicError_mmHg - acGain2 * diastolicError_mmHg;
      BLIM(aortaComplianceScale, 0.5, 1.5);
    }
    else
    {
      // This means that both errors are zero, which means you shouldn't have called me
      Error("Something is wrong with tuning logic");
    }
    m_ss << "Tuning paths, Current values : HeartRate(bpm):" << GetHeartRate(FrequencyUnit::Per_min) <<
                                        " Systolic(mmHg):" << systolic_mmHg << 
                                        " Diastolic(mmHg):" << diastolic_mmHg << 
                                        " Cardiac Output(mL/min):" << cardiacOutput_mL_Per_min << 
                                        " Mean CVP(mmHg):" << meanCVP_mmHg << 
                                        " MAP(mmHg):" << GetMeanArterialPressure(PressureUnit::mmHg) << 
                                        " BloodVolume(mL): " << blood_mL;
    Info(m_ss);
    TunePaths(systemicResistanceScale, systemicComplianceScale, aortaResistanceScale, aortaComplianceScale, rightHeartResistanceScale, venaCavaComplianceScale);
  }

  circuitFile.close();
  if (!success)
  {
    m_ss << "Unable to tune circuit to desired patient parameters. Final values : HeartRate(bpm):" << GetHeartRate(FrequencyUnit::Per_min) <<
                                                                              " Systolic(mmHg):" << GetSystolicArterialPressure(PressureUnit::mmHg) << 
                                                                              " Diastolic(mmHg):" << GetDiastolicArterialPressure(PressureUnit::mmHg) << 
                                                                              " Cardiac Output(mL/min):" << GetCardiacOutput(VolumePerTimeUnit::mL_Per_min) << 
                                                                              " Mean CVP(mmHg):" << GetMeanCentralVenousPressure(PressureUnit::mmHg) << 
                                                                              " MAP(mmHg):" << GetMeanArterialPressure(PressureUnit::mmHg) << 
                                                                              " BloodVolume(mL): " << blood_mL;
    Fatal(m_ss);
  }
  else
  {
    m_ss << "Successfully tuned circuit. Final values : HeartRate(bpm):" << GetHeartRate(FrequencyUnit::Per_min) <<
                                                    " Systolic(mmHg):" << GetSystolicArterialPressure(PressureUnit::mmHg) << 
                                                    " Diastolic(mmHg):" << GetDiastolicArterialPressure(PressureUnit::mmHg) << 
                                                    " Cardiac Output(mL/min):" << GetCardiacOutput(VolumePerTimeUnit::mL_Per_min) << 
                                                    " Mean CVP(mmHg):" << GetMeanCentralVenousPressure(PressureUnit::mmHg) << 
                                                    " MAP(mmHg):" << GetMeanArterialPressure(PressureUnit::mmHg) << 
                                                    " BloodVolume(mL): " << blood_mL;
    Info(m_ss);
    // Reset our substance masses to the new volumes
    for (SELiquidCompartment* c : m_data.GetCompartments().GetVascularLeafCompartments())
    {
      if (!c->HasVolume())
        continue;
      c->Balance(BalanceLiquidBy::Concentration);
      if (m_CirculatoryGraph->GetCompartment(c->GetName()) == nullptr)
        Info("Cardiovascular Graph does not have cmpt " + c->GetName());
      if (c->HasSubstanceQuantity(m_data.GetSubstances().GetHb()))// Unit testing does not have any Hb
        m_data.GetSaturationCalculator().CalculateBloodGasDistribution(*c);//so don't do this if we don't have Hb
    }
    for (SELiquidCompartment* c : m_data.GetCompartments().GetUrineLeafCompartments())
    {
      if (!c->HasVolume())
        continue;
      c->Balance(BalanceLiquidBy::Concentration);
    }
  }
}
//--------------------------------------------------------------------------------------------------
/// \brief
/// Method that changes path parameters during circuit tuning.
///
/// \details
/// Method that changes path parameters during circuit tuning.
//--------------------------------------------------------------------------------------------------
void Cardiovascular::TunePaths(double systemicResistanceScale, double systemicComplianceScale, double aortaResistanceScale, double aortaComplianceScale, double rightHeartResistanceScale, double venaCavaComplianceScale)
{
  double sp1_mmHg_s_Per_mL;
  if (systemicComplianceScale != 1.0)
  {
    for (SEFluidCircuitPath* p : m_systemicCompliancePaths)
    {
      sp1_mmHg_s_Per_mL = p->GetCapacitanceBaseline().GetValue(VolumePerPressureUnit::mL_Per_mmHg)*systemicComplianceScale;
      p->GetCapacitanceBaseline().SetValue(sp1_mmHg_s_Per_mL, VolumePerPressureUnit::mL_Per_mmHg);
      p->GetCapacitance().SetValue(sp1_mmHg_s_Per_mL, VolumePerPressureUnit::mL_Per_mmHg);
      p->GetNextCapacitance().SetValue(sp1_mmHg_s_Per_mL, VolumePerPressureUnit::mL_Per_mmHg);
    }
  }
  if (systemicResistanceScale != 1.0)
  {
    for (SEFluidCircuitPath *p : m_systemicResistancePaths)
    {
      sp1_mmHg_s_Per_mL = p->GetResistanceBaseline().GetValue(PressureTimePerVolumeUnit::mmHg_s_Per_mL)*systemicResistanceScale;

      p->GetResistanceBaseline().SetValue(sp1_mmHg_s_Per_mL, PressureTimePerVolumeUnit::mmHg_s_Per_mL);
      p->GetResistance().SetValue(sp1_mmHg_s_Per_mL, PressureTimePerVolumeUnit::mmHg_s_Per_mL);
      p->GetNextResistance().SetValue(sp1_mmHg_s_Per_mL, PressureTimePerVolumeUnit::mmHg_s_Per_mL);
    }
  }
  if (aortaComplianceScale != 1)
  {
    sp1_mmHg_s_Per_mL = m_AortaCompliance->GetCapacitanceBaseline().GetValue(VolumePerPressureUnit::mL_Per_mmHg)*aortaComplianceScale;
    m_AortaCompliance->GetCapacitanceBaseline().SetValue(sp1_mmHg_s_Per_mL, VolumePerPressureUnit::mL_Per_mmHg);
    m_AortaCompliance->GetCapacitance().SetValue(sp1_mmHg_s_Per_mL, VolumePerPressureUnit::mL_Per_mmHg);
    m_AortaCompliance->GetNextCapacitance().SetValue(sp1_mmHg_s_Per_mL, VolumePerPressureUnit::mL_Per_mmHg);
  }
  if (aortaResistanceScale != 1)
  {
    sp1_mmHg_s_Per_mL = m_AortaResistance->GetResistanceBaseline().GetValue(PressureTimePerVolumeUnit::mmHg_s_Per_mL)*aortaResistanceScale;
    m_AortaResistance->GetResistanceBaseline().SetValue(sp1_mmHg_s_Per_mL, PressureTimePerVolumeUnit::mmHg_s_Per_mL);
    m_AortaResistance->GetResistance().SetValue(sp1_mmHg_s_Per_mL, PressureTimePerVolumeUnit::mmHg_s_Per_mL);
    m_AortaResistance->GetNextResistance().SetValue(sp1_mmHg_s_Per_mL, PressureTimePerVolumeUnit::mmHg_s_Per_mL);
  }
  if (venaCavaComplianceScale != 1)
  {
    sp1_mmHg_s_Per_mL = m_VenaCavaCompliance->GetCapacitanceBaseline().GetValue(VolumePerPressureUnit::mL_Per_mmHg)*venaCavaComplianceScale;
    m_VenaCavaCompliance->GetCapacitanceBaseline().SetValue(sp1_mmHg_s_Per_mL, VolumePerPressureUnit::mL_Per_mmHg);
    m_VenaCavaCompliance->GetCapacitance().SetValue(sp1_mmHg_s_Per_mL, VolumePerPressureUnit::mL_Per_mmHg);
    m_VenaCavaCompliance->GetNextCapacitance().SetValue(sp1_mmHg_s_Per_mL, VolumePerPressureUnit::mL_Per_mmHg);
  }
  if (rightHeartResistanceScale != 1)
  {
    sp1_mmHg_s_Per_mL = m_RightHeartResistance->GetResistanceBaseline().GetValue(PressureTimePerVolumeUnit::mmHg_s_Per_mL)*rightHeartResistanceScale;
    m_RightHeartResistance->GetResistanceBaseline().SetValue(sp1_mmHg_s_Per_mL, PressureTimePerVolumeUnit::mmHg_s_Per_mL);
    m_RightHeartResistance->GetResistance().SetValue(sp1_mmHg_s_Per_mL, PressureTimePerVolumeUnit::mmHg_s_Per_mL);
    m_RightHeartResistance->GetNextResistance().SetValue(sp1_mmHg_s_Per_mL, PressureTimePerVolumeUnit::mmHg_s_Per_mL);
  }
}

//--------------------------------------------------------------------------------------------------
/// \brief
/// Adjusts vascular tone due to baroreceptor reflex, drug, and other effects
///
/// \details
/// Adjusts vascular tone due to baroreceptor reflex, drug, and other effects
//--------------------------------------------------------------------------------------------------
void Cardiovascular::AdjustVascularTone()
{
  /// \todo Add dilation (decreased resistance) to myocardium supply path if myocardium oxygen deficit event is active.

  //The baroreceptor response adjusts the systemic resistances and compliances according to the multiplier calculated in Nervous.cpp
  double UpdatedResistance_mmHg_s_Per_mL = 0.0;
  double UpdatedCompliance_mL_Per_mmHg = 0.0;
  double totalResistanceChange_mmHg_s_Per_mL = 0.0;
  double totalComplianceChange_mL_Per_mmHg = 0.0;
  if (m_data.GetNervous().HasBaroreceptorResistanceScale())
  {
    for (SEFluidCircuitPath* Path : m_systemicResistancePaths)
    {
      /// \todo We are treating all systemic resistance paths equally, including the brain.
      UpdatedResistance_mmHg_s_Per_mL = m_data.GetNervous().GetBaroreceptorResistanceScale().GetValue()*Path->GetResistanceBaseline(PressureTimePerVolumeUnit::mmHg_s_Per_mL);
      if (UpdatedResistance_mmHg_s_Per_mL < m_minIndividialSystemicResistance__mmHg_s_Per_mL)
      {
        UpdatedResistance_mmHg_s_Per_mL = m_minIndividialSystemicResistance__mmHg_s_Per_mL;
      }
      Path->GetNextResistance().SetValue(UpdatedResistance_mmHg_s_Per_mL, PressureTimePerVolumeUnit::mmHg_s_Per_mL);
    }
  }

  if (m_data.GetNervous().HasBaroreceptorComplianceScale())
  {
    for (SEFluidCircuitPath* Path : m_systemicCompliancePaths)
    {
      UpdatedCompliance_mL_Per_mmHg = m_data.GetNervous().GetBaroreceptorComplianceScale().GetValue()*Path->GetComplianceBaseline(VolumePerPressureUnit::mL_Per_mmHg);
      Path->GetNextCompliance().SetValue(UpdatedCompliance_mL_Per_mmHg, VolumePerPressureUnit::mL_Per_mmHg);
    }
  }

  //The drug response adjusts the systemic resistances according to the mean arterial pressure change calculated in Drugs.cpp
  double ResistanceChange = 0.0;
  if (m_data.GetDrugs().HasMeanBloodPressureChange())
  {
    double TuningParameter = 3.0;
    double CardiacOutput_mL_Per_s = GetCardiacOutput(VolumePerTimeUnit::mL_Per_s);
    if (CardiacOutput_mL_Per_s != 0.0)
      ResistanceChange = m_data.GetDrugs().GetMeanBloodPressureChange(PressureUnit::mmHg) / GetCardiacOutput(VolumePerTimeUnit::mL_Per_s);
    if (ResistanceChange < 0.0)
      TuningParameter = 0.8; //1.2;
    ResistanceChange *= TuningParameter;
  }

  //Drug effects on arterial pressure occur by increasing the systemic vascular resistance. This occurs every time step by updating the next flow resistance.
  //These effects are applied in HeartDriver() since its functionality is called every time step.
  if (std::abs(ResistanceChange) > ZERO_APPROX)
  {
    for (SEFluidCircuitPath* Path : m_systemicResistancePaths)
    {
      if (!Path->HasNextResistance())
        continue;
      UpdatedResistance_mmHg_s_Per_mL = Path->GetNextResistance(PressureTimePerVolumeUnit::mmHg_s_Per_mL);
      UpdatedResistance_mmHg_s_Per_mL += ResistanceChange * UpdatedResistance_mmHg_s_Per_mL / GetSystemicVascularResistance(PressureTimePerVolumeUnit::mmHg_s_Per_mL);
      if (UpdatedResistance_mmHg_s_Per_mL < m_minIndividialSystemicResistance__mmHg_s_Per_mL)
      {
        UpdatedResistance_mmHg_s_Per_mL = m_minIndividialSystemicResistance__mmHg_s_Per_mL;
      }
      Path->GetNextResistance().SetValue(UpdatedResistance_mmHg_s_Per_mL, PressureTimePerVolumeUnit::mmHg_s_Per_mL);
    }
  }
  MetabolicToneResponse();
}

//--------------------------------------------------------------------------------------------------
/// \brief
/// Calculates the heart rate from the period.
///
/// \details
/// When flow is detected, the heart rate is computed from the cardiac cycle duration. Because a 
/// time step is added right before the flow detection (in case the cardiac cycle is continuing)
/// we must peel off the time step here.
//--------------------------------------------------------------------------------------------------
void Cardiovascular::CalculateHeartRate()
{
  // The time that the flow actually decreased below the threshold was last time slice (when m_HeartFlowDetected
  // was set back to false), so we need to subtract one time step from the interval.
  double HeartRate_Per_s = 1.0 / (m_CurrentCardiacCycleDuration_s - m_dT_s);
  GetHeartRate().SetValue(HeartRate_Per_s * 60.0, FrequencyUnit::Per_min);
  m_CurrentCardiacCycleDuration_s = 0;
}

//--------------------------------------------------------------------------------------------------
/// \brief
/// Determines the heart rhythm.
///
/// \details
/// The heart rhythm is set to either Asystole or NormalSinus based on if the patient has an
/// active cardiac arrest or has triggered the asystole event some other way.
//--------------------------------------------------------------------------------------------------
void Cardiovascular::UpdateHeartRhythm()
{
  if (m_data.GetActions().GetPatientActions().HasCardiacArrest() ||
    m_data.GetEvents().IsEventActive(eEvent::Asystole))
  {
    SetHeartRhythm(eHeartRhythm::Asystolic);
  }
  else
  {
    SetHeartRhythm(eHeartRhythm::NormalSinus);
  }
}

//--------------------------------------------------------------------------------------------------
/// \brief
/// Increased pleural cavity pressures hinders venous return through increased resistance.
///
/// \details
/// When a lung collapses (as with pneumothorax), increased pleural cavity pressure pushes on the 
/// mediastinum and great veins. As an effect, the mediastinum is displaced and the great veins 
/// become kinked, leading to decreased venous return to the heart. This leads to increasing cardiac
/// and respiratory embarrasment. http://medind.nic.in/jac/t08/i1/jact08i1p42.pdf
//--------------------------------------------------------------------------------------------------
void Cardiovascular::CalculatePleuralCavityVenousEffects()
{
  //The left and right pleural pressures are likely to have large differences only due to a pneumothorax
  //Pressure difference causes a mediastinum shift
  double pleuralCavityPressureDiff_cmH2O = std::abs(m_leftPleuralCavity->GetPressure(PressureUnit::cmH2O) - m_rightPleuralCavity->GetPressure(PressureUnit::cmH2O));
  
  double maxPressureDiff_cmH2O = 20.0;
  double maxResistanceMultiplier = 10.0;
  pleuralCavityPressureDiff_cmH2O = MIN(pleuralCavityPressureDiff_cmH2O, maxPressureDiff_cmH2O);

  //Interpolate into a parabola to effect things much more at larger differences
  double min = 1.0;
  double max = maxResistanceMultiplier;
  double a = max - min;
  double factor = pleuralCavityPressureDiff_cmH2O / maxPressureDiff_cmH2O;
  double resistanceMultiplier = a * factor * factor + min;

  double rightHeartResistance_mmHg_s_Per_mL = m_RightHeartResistance->GetNextResistance(PressureTimePerVolumeUnit::mmHg_s_Per_mL);
  rightHeartResistance_mmHg_s_Per_mL *= resistanceMultiplier;
  
  //Dampen the change to prevent potential craziness
  //It will only change half as much as it wants to each time step to ensure it's critically damped and doesn't overshoot
  double dampenFraction_perSec = 0.001 * 50.0;

  double previousRightHeartResistance_mmHg_s_Per_mL = m_RightHeartResistance->GetResistance(PressureTimePerVolumeUnit::mmHg_s_Per_mL);
  double resistanceChange_L_Per_mmHg_s_Per_mL = (rightHeartResistance_mmHg_s_Per_mL - previousRightHeartResistance_mmHg_s_Per_mL) * dampenFraction_perSec * m_dT_s;

  rightHeartResistance_mmHg_s_Per_mL = previousRightHeartResistance_mmHg_s_Per_mL + resistanceChange_L_Per_mmHg_s_Per_mL;
  m_RightHeartResistance->GetNextResistance().SetValue(rightHeartResistance_mmHg_s_Per_mL, PressureTimePerVolumeUnit::mmHg_s_Per_mL);

  //For tuning
  //m_data.GetDataTrack().Probe("pleuralCavityPressureDiff_cmH2O", pleuralCavityPressureDiff_cmH2O);
  //m_data.GetDataTrack().Probe("resistanceMultiplier", resistanceMultiplier);
  //m_data.GetDataTrack().Probe("rightHeartResistance_mmHg_s_Per_mL", rightHeartResistance_mmHg_s_Per_mL);
}
