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 stated in 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 and tissue damage leads to distributive shock with inappropriate vasodilation. Some key points to consider in the management of sepsis and septic shock include:

• Early recognition and prompt administration of intravenous fluids and vasopressors are mandatory, with a goal of restoring a mean systemic arterial pressure of 65 to 70 mm Hg 1.
• Fluid therapy should aim to improve microvascular blood flow and increase cardiac output, with crystalloid solutions as the first choice 1.
• The use of dynamic over static variables to predict fluid responsiveness is recommended, where available 1. While peripheral resistance changes and decreased glomerular filtration rate occur in shock, they are consequences rather than primary causes of poor tissue perfusion. The fundamental issue is inadequate cardiac output failing to meet tissue oxygen demands, resulting in cellular dysfunction and organ failure. It is essential to follow the guidelines for the management of sepsis and septic shock, which emphasize the importance of early recognition, prompt fluid resuscitation, and appropriate use of vasopressors 1.

From the FDA Drug Label

Prolonged administration of any potent vasopressor may result in plasma volume depletion which should be continuously corrected by appropriate fluid and electrolyte replacement therapy If plasma volumes are not corrected, hypotension may recur when LEVOPHED is discontinued, or blood pressure may be maintained at the risk of severe peripheral and visceral vasoconstriction (e.g., decreased renal perfusion) with diminution in blood flow and tissue perfusion with subsequent tissue hypoxia and lactic acidosis and possible ischemic injury.

The cause of poor peripheral tissue perfusion in this patient is A. Low cardiac output due to septic shock, which can lead to anaerobic metabolism, lactic acidosis, increased capillary permeability, and pooling of blood peripherally, resulting in decreased venous return (VR) and cardiac output (COP). This is further complicated by the use of potent vasopressors like norepinephrine, which can cause severe peripheral and visceral vasoconstriction if not properly managed with fluid and electrolyte replacement therapy 2.

From the Research

Causes of Poor Peripheral Tissue Perfusion

The patient in question is experiencing septic shock, which can lead to poor peripheral tissue perfusion. The possible causes of poor peripheral tissue perfusion in this scenario are:

• Low cardiac output: This can occur due to the patient's septic shock, which can lead to decreased cardiac function and subsequently decreased peripheral tissue perfusion 3, 4, 5.
• Ineffective peripheral tissue perfusion: This can be caused by the patient's septic shock, which can lead to vasodilation and decreased peripheral resistance, resulting in poor peripheral tissue perfusion 3, 4, 5.
• Decreased glomerular filtration rate: This can occur due to the patient's septic shock, which can lead to decreased renal function and subsequently decreased glomerular filtration rate 6, 7.

Relationship Between Vasopressors and Peripheral Tissue Perfusion

The use of vasopressors, such as norepinephrine, can help increase peripheral tissue perfusion by increasing mean arterial pressure and cardiac output 3, 4, 5. However, high doses of vasopressors can also lead to decreased peripheral tissue perfusion due to vasoconstriction 6, 7.

Lactate Clearance and Peripheral Tissue Perfusion

Lactate clearance is an important indicator of peripheral tissue perfusion, and decreased lactate clearance can indicate poor peripheral tissue perfusion 4, 6. The use of vasopressors, such as norepinephrine, can help improve lactate clearance and subsequently improve peripheral tissue perfusion 4, 5.

Septic Shock and Peripheral Tissue Perfusion

Septic shock can lead to poor peripheral tissue perfusion due to the release of inflammatory mediators, which can cause vasodilation and decreased peripheral resistance 3, 4, 5. The use of vasopressors and other therapeutic interventions can help improve peripheral tissue perfusion in patients with septic shock 3, 4, 5, 6, 7.