Commit be4668fc authored by Aaron Bray's avatar Aaron Bray
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Merge branch '2.x' of https://gitlab.kitware.com/physiology/engine into 2.x

parents 2c78fd9b 1c2b874e
......@@ -193,7 +193,9 @@ Actions
The cardiac arrest action is used to externally initiate a cardiac arrest event (see @ref cardiovascular-arrest "Cardiac Arrest" event below). The cardiac arrest event is a cessation of all cardiac and respiratory function. The cardiac arrest event can be triggered by systems of the engine when physiological thresholds are reached (physiological cardiac arrest), or it can be triggered by the cardiac arrest action (interface-initiated cardiac arrest). The cardiac arrest insult can be thought of as an idiopathic sudden cardiac arrest.
#### Hemorrhage
A hemorrhage is a substantial blood loss that may lead to inadequate supply of oxygen to tissues and vital organs. Reduced blood volume leads to reduced cardiac output, reduced mean arterial pressure, and an increase in heart rate due to baroreceptor response. Hemorrhage is initiated in the engine by specifying the location (compartment) and bleed rate. Multiple hemorrhages may exist at any given time. After the hemorrhage has been specified, the total loss rate is the sum of each individual bleed rate. This value is set as a negative flow source in the vena cava. This results in a decrease in total blood volume that is linearly proportional to the total loss rate. This decrease in blood volume leads to a drop in arterial pressures and cardiac output. The baroreceptor reflex initiates an increase in heart rate to compensate for the reduced mean arterial pressure.
A hemorrhage is a substantial blood loss that may lead to inadequate supply of oxygen to tissues and vital organs. Reduced blood volume leads to reduced cardiac output, reduced mean arterial pressure, and an increase in heart rate due to baroreceptor response. Hemorrhage is initiated in the engine by specifying the location (compartment) and bleed rate. Multiple hemorrhages may exist at any given time. The user can specify and cardiovascular compartment to apply a hemorrhage. After the hemorrhage has been specified, the total loss rate is the sum of each individual bleed rate to that compartment. This value is set as a negative flow source. This results in a decrease in total blood volume that is linearly proportional to the total loss rate. This decrease in blood volume leads to a drop in arterial pressures and cardiac output. The baroreceptor reflex initiates an increase in heart rate to compensate for the reduced mean arterial pressure.
An internal hemorrhage can also be specified for abdominal cardiovascular compartments, including the aorta, vena cava, stomach, splanchnic, spleen, right and left kidneys, large and small intestines, and liver. The internal hemorrhage allows blood to flow into the abdominal cavity, increasing the pressure in the cavity. This pressure is applied to the aorta, increasing the localized blood pressure as a result of internal blood accumulation.
Additionally, as there is a decrease in total blood volume, there is an associated decrease in the substances found in the blood. Like blood volume, the decrease in the substance will be linearly proportional to the bleed rate. For more specific information regarding these substances and their loss due to bleeding, see @ref BloodChemistryMethodology and @ref SubstanceTransportMethodology. Figure 8 shows the blood volume and hemoglobin content before, during, and after a massive hemorrhage event with no intervention other than the cessation of hemorrhage. Figure 9 shows a hemorrhage event with subsequent saline administration. Note that the hemoglobin content remains diminished as the blood volume recovers with IV saline. By comparison, [Figure 11](@ref cardiovascular-blood-administration) shows a blood-product intervention following a hemorrhage event. In that figure, the hemoglobin increases with the blood infusion.
......@@ -243,7 +245,7 @@ A “tourniquet” may be applied to a bleeding distal portion of the bo
#### Intravenous Fluid Administration
Intravenous fluid administration is a continual injection of a compatible fluid into the veins of a patient that has suffered from fluid loss. Due to increasing volume from intravenous fluid administration, blood volume and arterial pressures will increase. Stroke volume will increase due to increased venous return, which will cause an increase in cardiac output. The baroreceptor response will lead to a decrease in the heart rate.
Intravenous fluid administration is simulated by applying a flow source to the vena cava. The flow source and duration of the administration is dictated by the user in the form of a flow rate and IV bag volume. This results in an increase in total blood volume, heart stroke volume, cardiac output, and arterial pressures. Due to increasing arterial pressures, the baroreceptor reflex will begin to decrease heart rate according to the error between the mean arterial pressure and its set point. Additional effects may occur depending on the type of fluid administered. Currently, the user may administer blood or saline. Each of these fluids is considered a compound substance with multiple substance components. Further information on the effect of substances during fluid administration can be found in @ref SubstanceTransportMethodology.
Intravenous fluid administration is simulated by applying a flow source to the vena cava. The flow source and duration of the administration is dictated by the user in the form of a flow rate and IV bag volume. This results in an increase in total blood volume, heart stroke volume, cardiac output, and arterial pressures. Due to increasing arterial pressures, the baroreceptor reflex will begin to decrease heart rate according to the error between the mean arterial pressure and its set point. Additional effects may occur depending on the type of fluid administered. Currently, the user may administer blood, saline, and/or packed red blood cells. Each of these fluids is considered a compound substance with multiple substance components. Further information on the effect of substances during fluid administration can be found in @ref SubstanceTransportMethodology.
@anchor cardiovascular-events
##Events
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Methodology Sources and References
@article{gault1966patterns,
author = {Gault, James H and Ross, John and Mason, Dean T},
journal = {Ciculation},
number = {November 1966},
pages = {833--847},
title = {{Patterns of Brachial Arterial Blood Flow in Conscious Human Subjects with and without Cardiac Dysfunction}},
url = {http://ahajournals.org},
volume = {XXXIV},
year = {1966}
}
@article{holland1998ultrasound,
issn = {0301-5629},
journal = {Ultrasound in medicine {\&} biology},
month = {oct},
number = {8},
pages = {1079--86},
pmid = {9833575},
title = {{Lower extremity volumetric arterial blood flow in normal subjects.}},
url = {http://www.ncbi.nlm.nih.gov/pubmed/9833575},
volume = {24},
year = {1998}
}
@Article{abbas2003echocardiographic,
Title = {Echocardiographic Determination of Mean Pulmonary Artery Pressure},
Author = {Abbas and others},
......
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