Critical Care · Year 4 · from Critical Care
Case 3: Ventilator Troubleshooting - High Pressure Alarm
Clinical Image
Source: Wikimedia Commons - Pneumothorax CXR - Public Domain
Case Presentation
A 28-year-old man is on ICU day 2 for severe ARDS from aspiration pneumonia following a drug overdose. He is on volume control ventilation with tidal volume 450 mL, respiratory rate 18, FiO2 60%, and PEEP 12 cmH2O. While on rounds, the ventilator suddenly alarms with repeated high pressure alerts. Peak inspiratory pressure has increased from 32 cmH2O to 55 cmH2O, and the ventilator is unable to deliver the set tidal volume. The patient is becoming agitated and desaturating from 94% to 85%. The team quickly disconnects the patient from the ventilator and initiates bag-valve-mask ventilation while troubleshooting. On examination, there is absent breath sounds on the right side with hyperresonance to percussion. The trachea is deviated to the left. A bedside chest X-ray shows a large right tension pneumothorax with mediastinal shift. Given the clinical picture consistent with tension pneumothorax causing hemodynamic compromise (blood pressure dropped to 78/50 mmHg), emergent needle decompression is performed in the right 2nd intercostal space at the midclavicular line, with immediate rush of air and improvement in blood pressure. A chest tube is placed in the right 5th intercostal space at the anterior axillary line with water seal drainage. The patient stabilizes with return of bilateral breath sounds and normalized peak pressures on the ventilator.
Key Learning Points
- High pressure alarms indicate increased resistance (secretions, bronchospasm, kinked tube) or decreased compliance (pneumothorax, atelectasis, ARDS worsening, dyssynchrony)
- When troubleshooting ventilator emergencies, disconnect the patient and bag-mask ventilate while systematically evaluating: (1) ETT patency/position, (2) pneumothorax, (3) bronchospasm, (4) dyssynchrony
- Tension pneumothorax is a clinical diagnosis requiring immediate treatment - do NOT wait for imaging in unstable patients; needle decompression at the 2nd intercostal space, midclavicular line provides immediate relief
- Barotrauma risk increases with high airway pressures; maintaining plateau pressure less than 30 cmH2O and driving pressure less than 15 cmH2O reduces this complication