PHTLS 9TH EDITION SELF-TEST 2026/2027 | Prehospital
Trauma Life Support Complete Solution | NAEMT | Pass
Guaranteed - A+ Graded
Section 1: Physiology of Trauma & Shock (Questions 1-15)
Question 1
A trauma patient has lost approximately 30% of their blood volume. According to PHTLS
classification, this patient is in which class of hemorrhagic shock?
A. Class I
B. Class II
C. Class III [CORRECT]
D. Class IV
Rationale: Class III hemorrhagic shock represents 30-40% blood volume loss
(1500-2000 mL in adults), characterized by tachycardia, tachypnea, hypotension, and
altered mental status. Class I is <15%, Class II is 15-30%, Class IV is >40%.
Correct Answer: C
Question 2
During compensated shock, the body maintains perfusion to vital organs primarily
through:
,A. Increased urine output to clear metabolic waste
B. Vasoconstriction, increased heart rate, and shunting blood to heart and brain
[CORRECT]
C. Vasodilation to increase peripheral perfusion
D. Decreased respiratory rate to conserve energy
Rationale: Compensated shock utilizes sympathetic nervous system activation:
vasoconstriction (splanchnic and peripheral beds), tachycardia, and blood shunting to
vital organs. Urine output decreases, vasodilation worsens shock, and respiratory rate
increases.
Correct Answer: B
Question 3
A trauma patient's blood gas shows a base deficit of -8 mEq/L. This finding indicates:
A. Respiratory alkalosis
B. Metabolic acidosis from tissue hypoperfusion [CORRECT]
C. Normal acid-base status
D. Respiratory acidosis
Rationale: Base deficit <-6 indicates metabolic acidosis from anaerobic metabolism and
lactate accumulation due to inadequate tissue perfusion. It is a marker of shock
severity and predictor of mortality. Normal is 0 to +2.
Correct Answer: B
Question 4
The primary cellular consequence of hemorrhagic shock is:
,A. Hyperoxygenation of tissues
B. Transition from aerobic to anaerobic metabolism [CORRECT]
C. Increased ATP production
D. Alkalosis at the cellular level
Rationale: Inadequate oxygen delivery forces cells to anaerobic metabolism, producing
lactate and limited ATP. This leads to cellular energy failure, organ dysfunction, and if
prolonged, cell death. ATP production decreases, and acidosis (not alkalosis) results.
Correct Answer: B
Question 5
A patient in decompensated shock presents with hypotension that does not respond to
fluid resuscitation. The blood pressure is 70/40 mmHg despite 2 liters of crystalloid.
This patient is transitioning to:
A. Compensated shock
B. Irreversible shock [CORRECT]
C. Neurogenic shock
D. Septic shock
Rationale: Failure to respond to fluid resuscitation with persistent hypotension indicates
progression to irreversible shock where cellular damage is extensive and death is likely
without immediate definitive intervention. Compensated shock has normal BP,
neurogenic shock has different etiology, septic shock is infectious.
Correct Answer: B
Question 6
, The Shock Index (SI) is calculated as:
A. Systolic BP divided by heart rate
B. Heart rate divided by systolic BP [CORRECT]
C. Diastolic BP divided by heart rate
D. Pulse pressure divided by heart rate
Rationale: Shock Index = HR / Systolic BP. Normal is 0.5-0.7. SI >0.9 indicates shock,
>1.4 indicates severe shock. It is more sensitive than vital signs alone for detecting
occult shock in trauma patients.
Correct Answer: B
Question 7
A 30-year-old trauma patient has a heart rate of 110 and systolic BP of 110 mmHg. The
Shock Index is:
A. 0.5
B. 1.0 [CORRECT]
C. 1.5
D. 2.0
Rationale: SI = HR / SBP = = 1.0. A normal 30-year-old should have SI ~0.5-0.7
(e.g., HR 70, BP 120 = 0.58). SI of 1.0 indicates compensated shock and requires
aggressive monitoring and intervention.
Correct Answer: B
Question 8
Trauma Life Support Complete Solution | NAEMT | Pass
Guaranteed - A+ Graded
Section 1: Physiology of Trauma & Shock (Questions 1-15)
Question 1
A trauma patient has lost approximately 30% of their blood volume. According to PHTLS
classification, this patient is in which class of hemorrhagic shock?
A. Class I
B. Class II
C. Class III [CORRECT]
D. Class IV
Rationale: Class III hemorrhagic shock represents 30-40% blood volume loss
(1500-2000 mL in adults), characterized by tachycardia, tachypnea, hypotension, and
altered mental status. Class I is <15%, Class II is 15-30%, Class IV is >40%.
Correct Answer: C
Question 2
During compensated shock, the body maintains perfusion to vital organs primarily
through:
,A. Increased urine output to clear metabolic waste
B. Vasoconstriction, increased heart rate, and shunting blood to heart and brain
[CORRECT]
C. Vasodilation to increase peripheral perfusion
D. Decreased respiratory rate to conserve energy
Rationale: Compensated shock utilizes sympathetic nervous system activation:
vasoconstriction (splanchnic and peripheral beds), tachycardia, and blood shunting to
vital organs. Urine output decreases, vasodilation worsens shock, and respiratory rate
increases.
Correct Answer: B
Question 3
A trauma patient's blood gas shows a base deficit of -8 mEq/L. This finding indicates:
A. Respiratory alkalosis
B. Metabolic acidosis from tissue hypoperfusion [CORRECT]
C. Normal acid-base status
D. Respiratory acidosis
Rationale: Base deficit <-6 indicates metabolic acidosis from anaerobic metabolism and
lactate accumulation due to inadequate tissue perfusion. It is a marker of shock
severity and predictor of mortality. Normal is 0 to +2.
Correct Answer: B
Question 4
The primary cellular consequence of hemorrhagic shock is:
,A. Hyperoxygenation of tissues
B. Transition from aerobic to anaerobic metabolism [CORRECT]
C. Increased ATP production
D. Alkalosis at the cellular level
Rationale: Inadequate oxygen delivery forces cells to anaerobic metabolism, producing
lactate and limited ATP. This leads to cellular energy failure, organ dysfunction, and if
prolonged, cell death. ATP production decreases, and acidosis (not alkalosis) results.
Correct Answer: B
Question 5
A patient in decompensated shock presents with hypotension that does not respond to
fluid resuscitation. The blood pressure is 70/40 mmHg despite 2 liters of crystalloid.
This patient is transitioning to:
A. Compensated shock
B. Irreversible shock [CORRECT]
C. Neurogenic shock
D. Septic shock
Rationale: Failure to respond to fluid resuscitation with persistent hypotension indicates
progression to irreversible shock where cellular damage is extensive and death is likely
without immediate definitive intervention. Compensated shock has normal BP,
neurogenic shock has different etiology, septic shock is infectious.
Correct Answer: B
Question 6
, The Shock Index (SI) is calculated as:
A. Systolic BP divided by heart rate
B. Heart rate divided by systolic BP [CORRECT]
C. Diastolic BP divided by heart rate
D. Pulse pressure divided by heart rate
Rationale: Shock Index = HR / Systolic BP. Normal is 0.5-0.7. SI >0.9 indicates shock,
>1.4 indicates severe shock. It is more sensitive than vital signs alone for detecting
occult shock in trauma patients.
Correct Answer: B
Question 7
A 30-year-old trauma patient has a heart rate of 110 and systolic BP of 110 mmHg. The
Shock Index is:
A. 0.5
B. 1.0 [CORRECT]
C. 1.5
D. 2.0
Rationale: SI = HR / SBP = = 1.0. A normal 30-year-old should have SI ~0.5-0.7
(e.g., HR 70, BP 120 = 0.58). SI of 1.0 indicates compensated shock and requires
aggressive monitoring and intervention.
Correct Answer: B
Question 8
