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Medicine

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Respiratory

Question
24 out of 26
 

Endotoxic shock is initiated by (AIIMS Nov 2010)



A Endothelium damage

B Peripheral vasodilation

C Decrease myocardial contractility

D Decrease blood volume

Ans. A

Endothelium damage

Pathophysiology of Septicemia

1). Endothelial injury (Ref: Hari, 18th ed., Page 2224)

a. Vascular endothelial injury as the major mechanism for multiorgan dysfunction.

b. Leukocyte-derived mediators and platelet-leukocyte-fibrin thrombi may contribute to vascular injury.

c. TNF-alpha induce vascular endothelial cells to produce and release cytokines, procoagulant molecules, platelet-activating factor (PAF), nitric oxide, and other mediators.

d. In addition, regulated cell-adhesion molecules promote the adherence of neutrophils to endothelial cells.

e. Endothelial cell activation can also promote increased vascular permeability, microvascular thrombosis, DIC, and hypotension.

f. Tissue oxygenation may decrease as the number of functional capillaries is reduced by luminal obstruction due to swollen endothelial cells, decreased deformability of circulating erythrocytes, leukocyte-platelet-fibrin thrombi, or compression by edema fluid.

2). Septic Shock

a. The hallmark of septic shock is a decrease in peripheral vascular resistance that occurs despite increased levels of vasopressor catecholamines. Systolic BP <90 mmHg.

b. Before this vasodilatory phase, many patients experience a period during which oxygen delivery to tissues is compromised by myocardial depression, hypovolemia, and other factors.

c. During this "hypodynamic" period, the blood lactate concentration is elevated, and central venous oxygen saturation is low.

d. Fluid administration is usually followed by the hyperdynamic, vasodilatory phase during which cardiac output is normal (or even high) and oxygen consumption is independent of oxygen delivery.

e. The blood lactate level may be normal or increased, and normalization of the central venous oxygen saturation (SvO2) may reflect either improved oxygen delivery or left-to-right shunting.

f. Prominent hypotensive molecules include nitric oxide, beta-endorphin, bradykinin, PAF, and prostacyclin.

Extra Edge: Table 270–4). Physiologic Characteristics of the Various Forms of Shock (Ref. Hari-18th ed., Pg- 2219)

Type of Shock

CVP and PCWP

Cardiac Output

Systemic Vascular Resistance

Venous O2 Saturation

1). Hypovolemic

2). Cardiogenic

3). Septic (Hyperdynamic)

↑↓

4). Neurogenic

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