What is the cause of poor peripheral tissue perfusion in a patient with abdominal internal hemorrhage, suspected bowel injuries, and crushed thigh injuries, complicated by wound infection and septic shock, following a Road Traffic Accident (RTA)?

From the Guidelines

The cause of poor peripheral tissue perfusion in an RTA patient with abdominal internal hemorrhage, bowel injuries, crushed thigh injuries, wound infections, and septic shock is low cardiac output (option A). In septic shock, the initial inflammatory response triggers anaerobic metabolism leading to lactic acidosis, as recommended by the Surviving Sepsis Campaign guidelines 1. This causes increased capillary permeability and vasodilation, resulting in peripheral blood pooling. Consequently, there is decreased venous return and cardiac output, creating a vicious cycle of worsening tissue perfusion. The hypovolemia from internal hemorrhage compounds this problem by further reducing preload. Additionally, the systemic inflammatory response from infections causes myocardial depression, further compromising cardiac function. Some key points to consider in the management of sepsis and septic shock include:

• Early quantitative resuscitation of the septic patient during the first 6 hours after recognition 1
• Administration of broad-spectrum antimicrobials therapy within 1 hour of the recognition of septic shock 1
• Initial fluid resuscitation with crystalloid and consideration of the addition of albumin in patients who continue to require substantial amounts of crystalloid to maintain adequate mean arterial pressure 1
• Norepinephrine as the first-choice vasopressor to maintain mean arterial pressure ≥65 mmHg 1 While peripheral resistance typically decreases in early septic shock due to vasodilation, the primary driver of poor tissue perfusion is the inadequate cardiac output that fails to meet metabolic demands of tissues, leading to organ dysfunction and cellular damage, as supported by the 2016 Surviving Sepsis Campaign guidelines 1.

From the Research

Causes of Poor Peripheral Tissue Perfusion

The patient's condition, characterized by abdominal internal haemorrhage, query bowel injuries, crushed thigh injuries, and septic shock, can lead to poor peripheral tissue perfusion due to several factors. The primary cause of poor peripheral tissue perfusion in this scenario is:

• Low cardiac output, which can be attributed to septic shock and cardiac dysfunction, as evidenced by studies 2, 3, 4, 5.
  • Septic shock can cause cardiac dysfunction, characterized by decreased contractility, impaired ventricular response to fluid therapy, and ventricular dilatation 3, 5.
  • This cardiac dysfunction can lead to decreased cardiac output, resulting in poor peripheral tissue perfusion.
• Anaerobic metabolism, which occurs when oxygen delivery to tissues is impaired, can also contribute to poor peripheral tissue perfusion 2.
  • Lactic acidosis, a consequence of anaerobic metabolism, can lead to increased capillary permeability and pooling of blood peripherally, further decreasing effective peripheral tissue perfusion.
• Other factors that may contribute to poor peripheral tissue perfusion in this patient include:
  • Hypovolemia, which can occur due to blood loss and fluid shifts 4.
  • Vasodilation, which can lead to decreased peripheral resistance and decreased blood pressure 4.
  • Increased permeability, which can cause fluid shifts and decreased effective circulating volume 4.

Relationship Between Septic Shock and Cardiac Dysfunction

Septic shock can cause cardiac dysfunction, which can lead to poor peripheral tissue perfusion. Studies have shown that septic shock can cause reversible biventricular dilatation, decreased ejection fraction, and decreased response to fluid resuscitation and catecholamine stimulation 3, 5.

• The pathophysiology of septic shock involves vasodilation, increased permeability, hypovolemia, and ventricular dysfunction, all of which can contribute to poor peripheral tissue perfusion 4.
• The treatment of septic shock, including fluid resuscitation, vasopressors, and inotropes, aims to restore adequate organ perfusion and oxygen delivery 3, 4, 5, 6.

Clinical Implications

The clinical implications of poor peripheral tissue perfusion in this patient are significant, and prompt recognition and treatment of septic shock and cardiac dysfunction are essential to reducing organ system injury and mortality 3, 4, 5, 6.

• Early recognition of sepsis and septic shock, and appropriate treatment with antibiotics, fluids, and vasopressors, can help reduce organ system injury and mortality 6.
• The use of inotropes, such as dobutamine, can help increase cardiac output and improve peripheral tissue perfusion in patients with septic shock 4.