What is the most common physiological response in a patient who develops septic shock syndrome 5 days after an exploratory (surgical procedure to examine internal organs) laparotomy?

Cellular Anaerobic Respiration is the Most Common Physiological Response in Septic Shock Following Exploratory Laparotomy

The most common physiological response in a patient who develops septic shock syndrome 5 days after an exploratory laparotomy is cellular anaerobic respiration (option C).

Pathophysiology of Septic Shock

Septic shock represents a severe form of sepsis characterized by profound circulatory, cellular, and metabolic abnormalities. In the setting of post-operative septic shock, several key physiological changes occur:

1. Cellular Anaerobic Respiration

   • As septic shock progresses, tissue hypoperfusion becomes prominent despite fluid resuscitation
   • Inadequate oxygen delivery to tissues forces cells to switch to anaerobic metabolism 1
   • This metabolic shift is evidenced by rising lactate levels, a hallmark finding in septic shock

2. Hemodynamic Changes

   • Initial vasodilation leads to relative hypovolemia
   • Myocardial depression occurs due to septic cardiomyopathy 2
   • Microcirculatory dysfunction impairs oxygen extraction at the tissue level

Why Cellular Anaerobic Respiration is the Correct Answer

The surviving sepsis guidelines emphasize that tissue hypoperfusion is a central feature of septic shock 1. When tissue perfusion is compromised, cells cannot receive adequate oxygen despite compensatory mechanisms, leading to:

• Shift from aerobic to anaerobic metabolism
• Accumulation of lactate
• Metabolic acidosis (not respiratory acidosis)
• Cellular dysfunction and eventually organ failure

Clinical indicators of tissue hypoperfusion in septic shock include:

• Abnormal capillary refill time
• Skin mottling
• Cool extremities
• Decreased urine output 1

Why Other Options Are Incorrect

1. Hypokalaemia (A) - While electrolyte abnormalities can occur in septic shock, hypokalaemia is not the most common physiological response. Potassium levels may actually increase due to cellular damage and acidosis.

2. Respiratory Acidosis (B) - Septic shock typically causes metabolic acidosis (from anaerobic metabolism), not respiratory acidosis. Patients often develop tachypnea and respiratory alkalosis initially as they attempt to compensate for metabolic acidosis 1.

3. Increased GFR (D) - Septic shock actually leads to decreased GFR due to renal hypoperfusion, not increased GFR. Acute kidney injury is a common complication of septic shock.

Clinical Implications

Understanding that cellular anaerobic respiration is the primary physiological response in septic shock guides management:

• Early fluid resuscitation is critical to restore tissue perfusion 1
• Vasopressors are indicated when fluid resuscitation fails to restore adequate perfusion 1
• Lactate monitoring helps assess the severity of anaerobic metabolism and response to treatment
• Source control (addressing the underlying infection) is essential, which may require reoperation 1

In a post-laparotomy patient with septic shock, prompt recognition of this pathophysiological state and aggressive management are essential to prevent progression to multiple organ dysfunction syndrome and death.