A student is caring for a patient who suffered massive blood loss after trauma. How does the student correlate the blood loss with the patient's mean arterial pressure (MAP)?
It causes vasoconstriction and increased MAP.
Lower blood volume lowers MAP.
It raises cardiac output and MAP.
There is no direct correlation to MAP.
The Correct Answer is B
Mean arterial pressure (MAP) is a measure of the average pressure within the arteries during one cardiac cycle. It represents the perfusion pressure that drives blood flow to organs and tissues. MAP is calculated using the formula:
MAP = Diastolic blood pressure + 1/3 (Systolic blood pressure - Diastolic blood pressure)
Blood loss, particularly in cases of significant hemorrhage, leads to a decrease in blood volume. When blood volume decreases, there is less circulating blood available to generate pressure within the arterial system. This reduction in blood volume results in decreased MAP.
Therefore, in the case of massive blood loss after trauma, the student can correlate it with a lower blood volume, which in turn leads to a lower MAP. The decrease in blood volume reduces the perfusion pressure, compromising organ and tissue perfusion
A. It causes vasoconstriction and increased MAP in (option A) is incorrect because: While vasoconstriction can occur as a compensatory mechanism to maintain blood pressure, it does not necessarily lead to an increased MAP in the context of significant blood loss.
C. It raises cardiac output and MAP in (option C) is incorrect because Blood loss typically leads to a reduction in cardiac output due to decreased blood volume. Therefore, it does not raise cardiac output and MAP.
D. There is no direct correlation to MAP in (option D) is incorrect because: There is indeed a direct correlation between blood loss and MAP. As blood volume decreases, MAP decreases as well.
Therefore, the correct correlation between blood loss and MAP is that lower blood volume lowers MAP.
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Related Questions
Correct Answer is B
Explanation
Lactate is a by-product of anaerobic metabolism that accumulates when there is insufficient oxygen supply to meet cellular metabolic demands. In the context of severe tissue hypoxia, such as in septic shock, the body may resort to anaerobic metabolism, leading to increased lactate production and elevated lactate levels in the blood.
Elevated lactate levels, typically above 4.0 mmol/L, are indicative of tissue hypoxia and inadequate oxygenation at the cellular level. Higher lactate levels, such as 9.0 mmol/L, suggest more severe tissue hypoxia and increased anaerobic metabolism.
A. Partial thromboplastin time (PTT) 64 seconds in (option A) is incorrect because: PTT is a laboratory test that evaluates the intrinsic pathway of the coagulation cascade. While coagulation abnormalities may occur in septic shock, PTT alone does not specifically indicate severe tissue hypoxia.
C. Potassium 2.8 mEq/L (2.8 mmol/L) (option C) is incorrect because Low potassium levels (hypokalemia) can be a concern in septic shock, but it does not directly indicate severe tissue hypoxia.
D. PaCO2 58 mm Hg in (option D) is incorrect because: PaCO2 refers to the partial pressure of carbon dioxide in arterial blood and is a measure of the respiratory status. While an elevated PaCO2 can be a sign of respiratory acidosis, it is not specific to severe tissue hypoxia.
Therefore, in a critically ill patient with septic shock, an elevated lactate level, such as 9.0 mmol/L, indicates severe tissue hypoxia and inadequate oxygenation at the cellular level
Correct Answer is A
Explanation
Disseminated intravascular coagulation (DIC) is a condition characterized by both widespread activation of the coagulation system and excessive clotting, leading to the consumption of clotting factors and platelets. This results in a prothrombotic state, which can lead to organ dysfunction and bleeding manifestations.
Elevated D-dimer levels are a characteristic finding in DIC. D-dimer is a fibrin degradation product that is elevated when there is excessive fibrin formation and breakdown. Elevated D-dimer indicates ongoing fibrinolysis and activation of the clotting system.
B. Decreased prothrombin time in (option B) is incorrect because: DIC is characterized by consumption of clotting factors, which can result in prolongation of the prothrombin time (PT) as well as other coagulation tests.
C. Decreased partial thromboplastin time in (option C) is incorrect because Similar to the prothrombin time, the partial thromboplastin time (PTT) can also be prolonged in DIC due to the consumption of clotting factors.
D. Elevated fibrinogen level in (option D) is incorrect because, In DIC, there is consumption of fibrinogen along with other clotting factors. Therefore, elevated fibrinogen levels are not consistent with the pathophysiology of DIC.
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