Certified Pediatric Emergency Nurse (CPEN) Practice Exam

What is a major mechanism of shock relating to heart function?

1. Pump failure

2. Volume depletion

3. Vasodilation

4. Increased resistance

The correct answer is: Pump failure

In the context of shock, pump failure is a critical mechanism as it directly impacts the heart's ability to effectively circulate blood throughout the body. This impairment can be due to several factors, including myocardial infarction (heart attack), cardiomyopathy, or significant arrhythmias, which diminish the heart's ability to generate sufficient cardiac output. When the heart fails to pump adequately, vital organs do not receive enough oxygenated blood, leading to cellular dysfunction and, ultimately, organ failure if not promptly addressed. Understanding pump failure is paramount in pediatric care since children can compensate for decreased cardiac output better than adults until they reach critical states. Recognizing the signs of pump failure early allows for timely interventions, such as administering inotropes or fluids, to support cardiac function and improve blood circulation. While volume depletion, vasodilation, and increased resistance are all important mechanisms of shock, they relate to different pathways and causes of shock that do not primarily stem from a direct compromise of the heart's pumping capability. Volume depletion refers to hypovolemia from fluid loss, vasodilation involves the widening of blood vessels causing decreased systemic vascular resistance, and increased resistance pertains to conditions like afterload issues that generally do not directly indicate pump failure of the heart itself. Understanding