PHTLS Knowledge 4 — Questions and Answers
Question 1: Which mechanism best explains why tension pneumothorax causes hemodynamic collapse?
- Massive hemorrhage into the pleural space
- Mediastinal shift compresses the vena cava, reducing venous return (Correct answer)
- Bronchospasm causes severe hypoxia
- Air embolism enters the coronary circulation
Correct answer: Mediastinal shift compresses the vena cava, reducing venous return
Tension pneumothorax shifts the mediastinum, kinking the vena cava and dramatically reducing preload, leading to obstructive shock.
Question 2: In PHTLS, which finding most specifically indicates increased intracranial pressure after head trauma?
- GCS of 14
- Pupils equal and reactive
- Cushing's triad (hypertension, bradycardia, irregular respirations) (Correct answer)
- Diaphoresis and tachycardia
Correct answer: Cushing's triad (hypertension, bradycardia, irregular respirations)
Cushing's triad is the classic late sign of herniation due to rising ICP and represents a neurological emergency.
Question 3: A trauma patient has absent breath sounds on the left and the trachea deviated to the right. What is the MOST likely diagnosis?
- Left hemothorax
- Left tension pneumothorax (Correct answer)
- Right pneumothorax
- Cardiac tamponade
Correct answer: Left tension pneumothorax
Left tension pneumothorax causes absent breath sounds on the affected side and tracheal deviation away from the lesion.
Question 4: According to PHTLS principles, permissive hypotension targets a systolic BP of approximately how much in penetrating torso trauma without TBI?
- 60 mmHg
- 80–90 mmHg (Correct answer)
- 120 mmHg
- 140 mmHg
Correct answer: 80–90 mmHg
Permissive hypotension targets SBP of 80–90 mmHg to maintain perfusion while minimizing clot disruption in penetrating trauma without TBI.
Question 5: Which of the following is the MOST reliable early indicator of hemorrhagic shock in a healthy adult?
- Decreased blood pressure
- Narrowed pulse pressure and anxiety (Correct answer)
- Loss of consciousness
- Bradycardia
Correct answer: Narrowed pulse pressure and anxiety
Early hemorrhagic shock causes compensatory vasoconstriction that narrows pulse pressure and produces anxiety before overt hypotension develops.
Question 6: When using the PHTLS primary survey, which action has the highest priority in a patient with uncontrolled extremity hemorrhage?
- Establish IV access
- Control the hemorrhage immediately (Correct answer)
- Assess airway patency
- Obtain a SAMPLE history
Correct answer: Control the hemorrhage immediately
PHTLS now places hemorrhage control (X — Exsanguinating hemorrhage) before airway management in the XABCDE sequence.
Question 7: A patient with blunt abdominal trauma develops hypotension and distension. Which organ is MOST commonly injured?
- Bladder
- Spleen (Correct answer)
- Stomach
- Pancreas
Correct answer: Spleen
The spleen is the most commonly injured solid abdominal organ in blunt trauma and is a major source of hemorrhagic shock.
PHTLS Knowledge 4
Which mechanism best explains why tension pneumothorax causes hemodynamic collapse?