A patient is in the early, compensated stage of hypovolemic shock. Which physiological response is primarily responsible for maintaining blood pressure during this stage?

Appeared in: NORCET 1 - 2020

Explanation

In early hypovolemic shock, decreased blood volume is detected by baroreceptors, triggering a powerful sympathetic nervous system (SNS) response.
The SNS stimulates the release of catecholamines (epinephrine and norepinephrine).
These hormones cause widespread peripheral vasoconstriction, which increases systemic vascular resistance (SVR).
The increase in SVR is the primary mechanism that raises and maintains blood pressure to perfuse vital organs during this initial stage.
Simultaneously, the SNS increases the heart rate (tachycardia) to further support cardiac output.

Option A: Parasympathetic stimulation causes vasodilation and a decreased heart rate (bradycardia), which would lower blood pressure and counteract the body's attempt to compensate for shock.
Option C: In shock, the body's priority is to conserve fluid. Hormonal responses (RAAS and ADH) lead to a significant decrease in urine output (oliguria), not an increase.
Option D: Antidiuretic hormone (ADH) is released to promote water reabsorption by the kidneys and concentrate urine, thereby conserving blood volume. Inhibition of ADH would lead to further fluid loss.

Clinical Relevance

Nursing practice connection: Prioritize focused assessment, early escalation, and real-time monitoring when managing Compensatory mechanisms in hypovolemic shock in acute care settings.
Nurses must recognize the early signs of compensated shock, such as tachycardia, cool and clammy skin (due to vasoconstriction), and anxiety, as blood pressure may still be normal.
Prompt identification and intervention (e.g., fluid resuscitation) during the compensated stage are crucial to prevent progression to decompensated shock, where blood pressure drops and organ damage begins.
What if the patient progresses to the decompensated stage? The primary finding would shift from maintained BP to significant hypotension, as the body's compensatory mechanisms (like vasoconstriction) fail. The clinical picture would include worsening tachycardia, weak pulses, and altered mental status.

How to Approach the Question

First, identify the core concept of the question: the body's response to hypovolemic shock.
Note the specific stage mentioned: 'early, compensated'. This is a critical clue, as the body's responses change in later stages.
The goal in the compensated stage is to 'maintain blood pressure'. Evaluate each option based on whether it would raise or lower blood pressure.
Analyze Option A: Parasympathetic stimulation lowers BP. Eliminate.
Analyze Option B: Sympathetic stimulation causes vasoconstriction, which raises BP. This is a plausible compensatory mechanism.
Analyze Option C: Increased urine output means fluid loss, which would lower BP. Eliminate.

Concept Tested & Keywords

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E6 Pathology-Textbook of PATHOLOGYHarsh Mohan Part 1 (1-214) p. 197-199

E6 Nelson Textbook of Pediatrics(2024) — Volume 1 p. 646-648

Practise the full NORCET 1 - 2020

Attempt every question from this paper in a timed mock, then review the full solution for each one.