Correct Answer: C — ETT obstruction or bronchospasm

Differentiating high peak vs. high plateau pressure is critical:

Finding	Cause	Problem
High Peak + Normal Plateau	Increased airway resistance	ETT kinking/obstruction, secretions, bronchospasm, biting the tube
High Peak + High Plateau	Decreased lung compliance	ARDS, pneumothorax, pulmonary edema, auto-PEEP

Formula: \[\text{Compliance} = \frac{V_T}{P_{\text{plateau}} - \text{PEEP}}\]
Normal compliance \(\approx 50 - 100 \text{ mL/cmH}_2\text{O}\)

Nursing action for high peak, normal plateau:

• Suction the ETT for secretions
• Check for tube kinking or patient biting
• Administer bronchodilator if bronchospasm suspected
• Assess breath sounds bilaterally