Question

CRITICAL CARE AND EMERGENCY NURSING

1. Describe the physical manifestations most commonly associated with the various shock states. Explain in detailed.

2. Describe prevention approaches that can be instituted in the critical care environment. Explain in detailed.

3. How does the heart work? Explain in detailed.

4. What causes of increased preload of the blood? Explain in detailed.

5. What causes of decreased preload of the blood? Explain in detailed.

Answer 1

1Q).

Shock is an emergency medical condition characterized by tissue hypoxia or reduced tissue perfusion, which is a common symptom in all types of shock. The imbalance between oxygen supply and demand can lead to organ failure and death. Different causes of shock include sepsis, allergic reactions, cardiac failure, and severe hemorrhage or fluid loss (hypovolemia).

Hypovolemic shock:

Etiology: It occurs due to the inadequate intravascular fluid volume resulting from acute blood loss and fluid loss due to persistent diarrhea, vomiting, and dehydration.

Pathophysiology: In response to the decreased blood volume, the cardiovascular system, endocrine system, renal system, and hematologic system respond in different ways. The primary consequences of hypovolemia include,

· The hematologic system activates the coagulation cascade if bleeding occurs

· The cardiovascular system initially increases the heart rate and sympathetic response. As a result, the peripheral blood flow decreases to restore the circulation to the vital organs such as the brain, heart, lungs, and kidneys. However, the overall drop in blood volume reduces the venous return and stroke volume. This results in reduced cardiac output and tissue perfusion.

· The renal system responds by stimulating the renin release. Renin stimulates aldosterone secretion and the formation of angiotensin –II, both of which play a key role in the reversal of hemorrhagic shock.

· Endocrine system releases the ADH (anti-diuretic hormone) to reduce the fluid excretion through the kidneys.

Cardiogenic shock:

Etiology: The cardiogenic shock typically occurs as a consequence of cardiac ischemia, myocardial infarction (MI), ventricular septal defect, septic shock with myocardial depression, right ventricular, and left ventricular failure.

Pathophysiology: In contrast to the hypovolemic shock, the vascular fluid volume remains normal in cardiogenic shock. But the cardiac tissue dies in myocardial infarction, which causes pump failure and reduces coronary circulation. This further worsens the death of cardiac tissue (progresses in a positive feedback loop), eventually leads to reduced cardiac output and increased afterload. Decreased cardiac output decreases tissue perfusion. As a compensatory mechanism, the heart rate increases, which further increases the myocardial oxygen demand and cardiac ischemia.