PHTLS - Prehospital Trauma Life Support Prehospital Trauma Life Support Shock and Hemorrhage Control 1 — Questions and Answers
Question 1: In PHTLS, which physiologic mechanism is the PRIMARY cause of death in hemorrhagic shock when the body's compensatory mechanisms fail?
- Severe metabolic alkalosis from bicarbonate loss
- Inadequate cellular oxygen delivery leading to anaerobic metabolism and organ failure (Correct answer)
- Systemic inflammatory response overwhelming the immune system
- Neurogenic depression of the cardiac conduction system
Correct answer: Inadequate cellular oxygen delivery leading to anaerobic metabolism and organ failure
PHTLS defines shock as inadequate tissue perfusion and oxygenation. When compensatory mechanisms (vasoconstriction, tachycardia) are exhausted, cells shift to anaerobic metabolism, producing lactic acidosis, which progresses to multi-organ failure and death.
Question 2: According to PHTLS hemorrhagic shock classification, a patient presenting with heart rate of 118 bpm, mildly anxious affect, and normal blood pressure most likely falls into which class?
- Class I
- Class II (Correct answer)
- Class III
- Class IV
Correct answer: Class II
Class II hemorrhage (750–1500 mL blood loss, 15–30% volume) typically causes tachycardia (100–120 bpm) and anxiety while systolic BP is still maintained through compensatory vasoconstriction. BP drop is not yet measurable at this stage.
Question 3: When applying a wound packing technique for hemorrhage control in a non-compressible truncal wound, PHTLS recommends packing the wound with hemostatic gauze and then:
- Applying a tourniquet proximal to the wound site
- Holding firm, direct manual pressure for a minimum of 3 minutes (Correct answer)
- Loosely filling the cavity and covering with a pressure dressing
- Applying a chest seal before wound packing
Correct answer: Holding firm, direct manual pressure for a minimum of 3 minutes
PHTLS requires at least 3 minutes of firm, uninterrupted direct manual pressure after hemostatic gauze packing to allow the agent to activate and the clot to form. Releasing pressure too early disrupts clot formation and restarts bleeding.
Question 4: The 'lethal triad' in trauma, which PHTLS providers are taught to recognize and prevent, consists of:
- Hypovolemia, tachycardia, and coagulopathy
- Hypothermia, acidosis, and coagulopathy (Correct answer)
- Hypoxia, hypotension, and hyperkalemia
- Bradycardia, alkalosis, and thrombocytopenia
Correct answer: Hypothermia, acidosis, and coagulopathy
The lethal triad — hypothermia, acidosis, and coagulopathy — is a self-reinforcing cycle in trauma patients. Hypothermia impairs clotting enzyme function, acidosis worsens coagulopathy, and ongoing bleeding deepens acidosis; PHTLS providers focus on prevention through rapid hemorrhage control and warming.
Question 5: PHTLS supports a strategy of 'permissive hypotension' in penetrating trauma patients with uncontrolled internal hemorrhage. What is the PRIMARY goal of this approach?
- To minimize the risk of pulmonary edema from aggressive fluid loading
- To avoid diluting clotting factors and dislodging early clots while maintaining minimal perfusion (Correct answer)
- To prevent cerebral herniation from excessive intracranial pressure
- To reduce cardiac workload and myocardial oxygen demand
Correct answer: To avoid diluting clotting factors and dislodging early clots while maintaining minimal perfusion
Aggressive IV fluid resuscitation raises blood pressure, which can mechanically dislodge early clots and dilute remaining clotting factors, worsening coagulopathy. Permissive hypotension targets a mean arterial pressure sufficient for minimal brain and organ perfusion while limiting this harm until surgical hemorrhage control.
Question 6: According to PHTLS principles, which assessment finding most reliably indicates that a trauma patient has transitioned from compensated to decompensated hemorrhagic shock?
- Heart rate rising above 100 bpm
- Capillary refill time greater than 2 seconds
- A falling systolic blood pressure despite ongoing care (Correct answer)
- Patient reporting feeling thirsty and anxious
Correct answer: A falling systolic blood pressure despite ongoing care
A falling systolic blood pressure signals that the body's compensatory mechanisms (vasoconstriction, tachycardia, fluid shifts) have been overwhelmed. PHTLS identifies this drop as the marker of decompensated shock and an immediate threat to life requiring aggressive hemorrhage control and rapid transport.
PHTLS - Prehospital Trauma Life Support Prehospital Trauma Life Support Shock and Hemorrhage Control 1
In PHTLS, which physiologic mechanism is the PRIMARY cause of death in hemorrhagic shock when the body's compensatory mechanisms fail?