Septs and Septic shock

What is shock?

A state of cellular and tissue hypoxia due to reduced oxygen delivery, increased oxygen consumption, inadequate oxygen utilization, or a combination of these processes.

What are the determinants of tissue oxygenation?

Oxygen delivery, which is determined by cardiac output, hemoglobin levels, and arterial oxygen saturation.

What is the calculation for Mean Arterial Pressure (MAP)?

MAP = (2/3)DBP + (1/3)SBP.

What is the goal MAP in most shock states?

The goal MAP is typically ≥ 65 mmHg.

What characterizes hypovolemic shock?

Caused by extracellular volume depletion leading to decreased preload; characteristics include low preload, low cardiac output, and high afterload.

What are the common causes of hypovolemic shock?

Significant blood loss, dehydration, or severe burns.

What characterizes cardiogenic shock?

Caused by pump failure; characteristics include high preload, low cardiac output, and high afterload.

What are two primary causes of cardiogenic shock?

Myocardial infarction and arrhythmias.

What characterizes vasodilatory shock?

Caused by excessive vasodilation; characteristics include high cardiac output (early phase), low systemic vascular resistance, and low/normal pulmonary capillary wedge pressure.

What are common causes of vasodilatory shock?

Sepsis, anaphylaxis, and neurogenic shock.

What characterizes obstructive shock?

Caused by physical obstruction to blood flow; characteristics include high preload, low cardiac output, and high afterload.

Define sepsis.

Life-threatening organ dysfunction caused by a dysregulated host response to infection.

What is the Sequential Organ Failure Assessment (SOFA) score threshold to define sepsis?

An acute change in total SOFA score ≥ 2 points due to infection.

What is the definition of septic shock?

Sepsis with persisting hypotension (MAP < 65) despite adequate volume resuscitation and requiring vasopressor use.

What is the importance of lactate level in septic shock?

A serum lactate level > 2 mmol/L indicates septic shock.

What are risk factors for developing infections leading to sepsis?

Extremes of age and presence of pre-existing conditions like heart failure, diabetes, COPD, cirrhosis, alcohol dependence, end stage renal disease, and cancer.

What are common sites of infection in sepsis?

Lungs, intra-abdominal space, genitourinary tract.

What types of bacteria are commonly associated with gram-negative sepsis?

E. Coli, Klebsiella, Proteus species, Enterobacter species, Pseudomonas aeruginosa.

How does gram-positive sepsis occur?

Through the presence of peptidoglycan on the cell wall surface, which is pro-inflammatory.

What are some pro-inflammatory mediators released during sepsis?

TNF-alpha, IL-6, IL-12, released by endothelial cells and macrophages.

What is the consequence of systemic inflammation during sepsis?

Injured endothelial cells causing decreased arteriolar responsiveness and blood flow into capillaries.

What is disseminated intravascular coagulation (DIC)?

A serious complication that can arise in septic shock, leading to widespread clotting in small blood vessels.

What is an early clinical presentation of sepsis?

General malaise or myalgia, fever or hypothermia, elevated WBC, chills, tachycardia, tachypnea, and change in mental status.

What are late signs of sepsis?

Hypotension leading to organ dysfunction, oliguria, hypo/hyperventilation, hyperlactemia, abnormal blood glucose levels, and decreased mental status.

What does septic shock lead to?

Organ hypoperfusion and multiple organ dysfunction.

What happens to the coagulation cascade during sepsis?

Pro-inflammatory cytokines cause a hypercoagulable state through pro-coagulant and anti-fibrinolytic mechanisms.

What characterizes late sepsis?

It varies depending on site of infection and organ dysfunction, including hypotension and additional evidence of infection.

What is the hemodynamic effect of sepsis?

Hypotension, tachycardia, high cardiac output, and myocardial dysfunction.

What factor increases mortality in septic shock compared to sepsis?

The presence of persistent hypotension despite treatment and other organ failures.