Which physiological event is a hallmark of the progressive stage of shock, initiating a vicious cycle of card… - RUHS, Jaipur, M.Sc Nursing Entrance Exam-2015

RUHS, Jaipur, M.Sc Nursing Entrance Exam-2015

Medical & Surgical Nursing

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Appeared in: RUHS, Jaipur, M.Sc Nursing Entrance Exam-2015

Explanation

The progressive stage of shock is defined by the failure of compensatory mechanisms and the start of positive feedback loops that cause rapid deterioration.
A key event is cardiac depression. As systemic blood pressure falls, blood flow to the heart's own coronary arteries decreases.
This lack of perfusion (myocardial ischemia) weakens the heart muscle, reducing its ability to pump blood (decreased cardiac output).
The decreased cardiac output causes a further drop in blood pressure, which in turn worsens coronary blood flow, creating a vicious cycle of decline.

Option A: Activation of sympathetic reflexes (like increased heart rate and vasoconstriction) is a primary compensatory mechanism of the nonprogressive (compensated) stage of shock. It is a negative feedback response designed to maintain blood pressure and prevent deterioration.
Option C: Fluid conservation via the renin-angiotensin-aldosterone system (RAAS) is another crucial compensatory mechanism that occurs during the nonprogressive (compensated) stage. It helps to increase blood volume and pressure.
Option D: The progressive stage is defined by steady deterioration that leads to death without medical therapy. Full recovery without intervention is the characteristic outcome of the nonprogressive (compensated) stage, where the body's own mechanisms successfully restore circulatory function.

Clinical Relevance

Nursing practice connection: This is primarily an exam-oriented knowledge point with limited direct bedside application, so retain Pathophysiology of the Stages of Shock as background academic context rather than a clinical decision trigger.
Recognizing the transition from compensated to progressive shock is critical for nurses. Signs like worsening hypotension, altered mental status, and metabolic acidosis indicate that compensatory mechanisms are failing.
The goal of shock management is to intervene during the compensated stage to correct the underlying cause (e.g., stop bleeding, administer fluids, support heart function) before the vicious cycle of the progressive stage begins.
Once the progressive stage starts, interventions must be rapid and aggressive to break the cycle, as the patient's condition can decline very quickly.

How to Approach the Question

First, identify the key terms in the question: 'progressive stage of shock' and 'vicious cycle'.
Recall the three stages of shock: nonprogressive (compensated), progressive, and irreversible.
Remember that the compensated stage is characterized by the body's own 'negative feedback' mechanisms trying to fix the problem (e.g., sympathetic reflexes, RAAS).
The progressive stage is defined by the failure of these mechanisms and the onset of 'positive feedback' loops or 'vicious cycles' where the problem gets worse and worse.
Evaluate each option: 'Sympathetic reflexes' and 'renin-angiotensin system' are compensatory mechanisms. 'Full recovery' is the outcome of the compensated stage.
Cardiac depression due to poor coronary flow perfectly describes a positive feedback loop: low pressure weakens the heart, which causes even lower pressure. This matches the definition of the progressive stage.

Concept Tested & Keywords

Concept Tested: Pathophysiology of the Stages of Shock
Stem keywords: progressive stage of shock, physiological event, hallmark, vicious cycle, cardiovascular deterioration
Lead-in keywords: Which
Negative lead-in flag: false

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E6 Physiology Guyton 4SAE Part 2A pp. 27-29, 28-30

E6 Pathology- ROBBINS & COTRAN PATHOLOGIC BASIS OF DISEASE 10TH Ed p. 145-147