In the following conditions, indicate what factor/s influence the cardiac output: PRELOAD, CONTRACTILITY, AFTERLOAD, HEART RATE. Explain the why the factor/s affects cardiac output in 1 to 2 sentences.
a. High blood pressure
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The blood pressure is directly proportional to cardiac output, volume of blood, peripheral vascular resistance, and the viscosity of blood and rigidity of vessel walls (Lapum, 2020). This means that when blood pressure increases, all of these factors increase as well and vice versa.
b. Massive bleeding
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Massive bleeding, whether internal or external, can result in a fall in central venous pressure and cardiac filling. This phenomena results in a reduced cardiac output and arterial pressure (Klabunde, 2021).
c. the drug dopamine
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In clinical settings, dopamine is used to support cardiac output and blood pressure (Jakob, 2002). This is because dopamine produces positive and inotropic effects on the myocardium.
d. Running a sprint
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Running a sprint can affect cardiac output by encouraging the heart to beat faster to supply more blood (and oxygen) for your body.
e. Hyperthyroidism with increased secretion of thyroid hormones
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High cardiac output and left ventricular hypertrophy is caused by hyperthyroidism in the early stages, while biventricular dilatation and congestive heart failure happens in the late hyperthyroidism stages (Osuna, et. al, 2017).
f. Massive myocardial infarction (cardiac tissue death)
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Cardiac tissue death can cause the loss of viable myocardium, which can impair global cardiac function. This phenomena can also reduce cardiac output or even result in cardiogenic shock if damages are severe (Klabunde, 2022).
g. Hypothermia
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Noradrenaline of the skin happens during hypothermia. This causes the cardiac output to fall below a core temperature of 34℃ due to the increase in bradycardia (Deussen, 2007).
h. Emotional distress
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Emotional distress can cause increased oxygen demand on the body (increased heart rate), spasm of the coronary blood vessels (increased blood pressure), and electrical instability in the heart’s conduction system (Torpy, 2007).
RESOURCES:
Cardiac Output. (2022, January 10). MyHealth.Alberta.ca. https://myhealth.alberta.ca/Health/Pages/conditions.aspx?hwid=tx4080abc
Dopamine: Uses, Interactions, Mechanism of Action | DrugBank Online. (n.d.). DrugBank. https://go.drugbank.com/drugs/DB00988
Klabunde, R. E. (2022, August 30). The Pharmacologic Treatment of Myocardial Infarction. CV Pharmacology. https://www.cvpharmacology.com/clinical%20topics/myocardial%20infarction
Klabunde, R. E. (2021, February 2). Hemorrhagic Shock. CV Pharmacology. https://www.cvphysiology.com/Blood%20Pressure/BP031
Libretexts. (2020, August 14). 5.15: Factors That Influence Blood Pressure. Medicine LibreTexts. https://med.libretexts.org/Bookshelves/Allied_Health/Book:_Vital_Sign_Measurement_Across_the_Lifespan_(Lapum_et_al.)/05:_Blood_Pressure/5.15:_Factors_That_Influence_Blood_Pressure
NCBI - WWW Error Blocked Diagnostic. (n.d.). https://pubmed.ncbi.nlm.nih.gov/12095139/
NCBI - WWW Error Blocked Diagnostic. (n.d.-c). https://pubmed.ncbi.nlm.nih.gov/17554514/
NCBI - WWW Error Blocked Diagnostic. (n.d.-b). https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5512680/
Torpy, J. M. (2007, October 10). Chronic Stress and the Heart. JAMA Network. https://jamanetwork.com/journals/jama/fullarticle/209139