PHTLS Knowledge 4

Question 1

Which mechanism best explains why tension pneumothorax causes hemodynamic collapse?

Accepted Answer

Mediastinal shift compresses the vena cava, reducing venous return

Answer

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?

Accepted Answer

Cushing's triad (hypertension, bradycardia, irregular respirations)

Answer

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?

Accepted Answer

Left tension pneumothorax

Answer

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?

Accepted Answer

80–90 mmHg

Answer

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?

Accepted Answer

Narrowed pulse pressure and anxiety

Answer

Early hemorrhagic shock causes compensatory vasoconstriction that narrows pulse pressure and produces anxiety before overt hypotension develops.

PHTLS - Prehospital Trauma Life Support Practice Test