A 28-year-old woman is admitted with Class II hemorrhagic shock following blunt abdominal trauma from a fall. During the initial resuscitation phase, all of the following interventions are appropriate EXCEPT:

Question

Accepted Answer

C. Aggressive hyperventilation to maintain PaCO₂ at 25–30 mmHg to improve cerebral perfusion and reduce intracranial pressure. ## Hemorrhagic Shock Resuscitation: Appropriate vs. Inappropriate Interventions

### Overview of Class II Hemorrhagic Shock

**Key Point:** Class II hemorrhagic shock (15–30% blood volume loss) presents with tachycardia, tachypnea, mild anxiety, and decreased urine output. It is partially compensated and requires prompt fluid resuscitation and identification of bleeding source.

### Evaluation of Each Intervention

| Intervention | Appropriateness | Rationale |
|--------------|-----------------|----------|
| 2 L crystalloid bolus (warmed) | ✓ **Appropriate** | ATLS protocol recommends initial 1–2 L crystalloid bolus for Class II–III shock. Warmed fluids prevent hypothermia-induced coagulopathy. |
| Type O-negative blood for massive hemorrhage | ✓ **Appropriate** | O-negative (universal donor) blood is indicated when massive hemorrhage is anticipated before type-matched blood is available. Prevents delay in transfusion. |
| Aggressive hyperventilation (PaCO₂ 25–30 mmHg) | ✗ **INAPPROPRIATE** | Hyperventilation causes respiratory alkalosis, which impairs oxygen delivery to tissues, worsens cerebral vasoconstriction, and increases risk of arrhythmias. Contraindicated in hemorrhagic shock. |
| Large-bore IV access (16–18 G) and IO access | ✓ **Appropriate** | Large-bore peripheral lines maximize flow rate. Intraosseous access is a valid alternative when peripheral access fails, especially in children or during cardiac arrest. |

### Clinical Pearl

**Hyperventilation in Trauma:**
- ~~Hyperventilation improves oxygenation in hemorrhagic shock~~ — **FALSE**
- Hyperventilation causes **respiratory alkalosis**, which:
  - Shifts the oxygen–hemoglobin dissociation curve **left** (reduces oxygen release to tissues)
  - Causes cerebral vasoconstriction (worsens perfusion)
  - Increases risk of cardiac arrhythmias
- **Appropriate ventilation:** Maintain normal PaCO₂ (35–45 mmHg) with adequate oxygenation (SpO₂ >94%)

### High-Yield Concept

**Mnemonic — ATLS Resuscitation Priorities in Hemorrhagic Shock:**
- **A**irway with cervical spine protection
- **B**reathing with normal ventilation (not hyperventilation)
- **C**irculation with large-bore IV access, warmed fluids, and early blood transfusion
- **D**isability assessment
- **E**xposure and environment (prevent hypothermia)

### Warning

**Common Exam Trap:** Hyperventilation is sometimes confused with beneficial oxygenation. Remember: in hemorrhagic shock, the problem is **tissue perfusion**, not oxygenation alone. Hyperventilation worsens perfusion by causing alkalosis and vasoconstriction.

[cite:ATLS 10th Edition, American College of Surgeons; Harrison 21e Ch 297]

Answer

A. Rapid infusion of 2 liters of warmed crystalloid (normal saline or Ringer's lactate) as an initial bolus

Answer

B. Placement of two large-bore intravenous cannulas (16–18 gauge) and consideration of intraosseous access if peripheral venous access is difficult

Answer

D. Immediate type and cross-match of blood; transfusion of O-negative blood if massive hemorrhage is suspected before type-matched blood is available

A 28-year-old woman is admitted with Class II hemorrhagic shock following blunt abdominal trauma from a fall. During the initial resuscitation phase, all of the following interventions are appropriate EXCEPT:

Explanation

Hemorrhagic Shock Resuscitation: Appropriate vs. Inappropriate Interventions

Overview of Class II Hemorrhagic Shock

Evaluation of Each Intervention

Clinical Pearl

High-Yield Concept

Warning

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Intervention	Appropriateness	Rationale
2 L crystalloid bolus (warmed)	✓ Appropriate	ATLS protocol recommends initial 1–2 L crystalloid bolus for Class II–III shock. Warmed fluids prevent hypothermia-induced coagulopathy.
Type O-negative blood for massive hemorrhage	✓ Appropriate	O-negative (universal donor) blood is indicated when massive hemorrhage is anticipated before type-matched blood is available. Prevents delay in transfusion.
Aggressive hyperventilation (PaCO₂ 25–30 mmHg)	✗ INAPPROPRIATE	Hyperventilation causes respiratory alkalosis, which impairs oxygen delivery to tissues, worsens cerebral vasoconstriction, and increases risk of arrhythmias. Contraindicated in hemorrhagic shock.
Large-bore IV access (16–18 G) and IO access	✓ Appropriate	Large-bore peripheral lines maximize flow rate. Intraosseous access is a valid alternative when peripheral access fails, especially in children or during cardiac arrest.