How to manage persistent high airway pressure in a patient on a ventilator?

Management of Persistent High Airway Pressure in Ventilated Patients

When confronted with persistent high airway pressure alarms, immediately check for HME filter blockage from moisture accumulation, as this is a frequently overlooked mechanical cause that can be mistaken for patient deterioration and may itself cause clinical compromise. 1

Systematic Approach to High Airway Pressure

Immediate Circuit Assessment

• Check the HME filter first - if it has become wet, it will cause circuit obstruction and must be replaced immediately 1
• Verify all circuit connections are secure using push-twist technique to prevent accidental disconnections 1
• Ensure the tracheal tube is not kinked or obstructed 1
• Perform closed tracheal suction to clear secretions 1

Endotracheal Tube Position and Cuff Management

• Verify tube depth at every shift and document changes to minimize displacement risk 1, 2
• Measure cuff pressure with a manometer - when using high airway pressures, ensure cuff pressure is at least 5 cmH2O above peak inspiratory pressure to prevent air leak 1, 2, 3
• Increase cuff pressure before recruitment maneuvers to ensure no cuff leak develops 1
• Check tube position and cuff pressure both before and after any patient repositioning, including prone positioning, turning, nasogastric tube manipulation, or oral care 1, 2

Ventilator Settings Optimization

• Assess plateau pressure to ensure it remains below 30 cmH2O for lung-protective ventilation 2, 3
• Verify tidal volume is maintained at 4-8 mL/kg predicted body weight 2, 3
• Document tidal volume as mL/kg predicted body weight rather than absolute values 3
• Assess for auto-PEEP and total PEEP levels 3
• Consider driving pressure assessment to prevent ventilator-induced lung injury 3

Important distinction: Peak airway pressure predominantly reflects inspiratory flow and airway resistance, while plateau pressure (measured during inspiratory hold) reflects lung compliance and actual alveolar pressure 4, 5, 6. Peak pressure alone does not reliably indicate pulmonary hyperinflation 5.

Patient-Related Causes

• Ensure adequate sedation - inadequate sedation causes patient-ventilator dyssynchrony and increased airway pressures 1
• Consider neuromuscular blockade if patient is fighting the ventilator despite adequate sedation 1
• Assess for bronchospasm, pneumothorax, pulmonary edema, or worsening lung compliance 4
• In patients with severe airflow obstruction, measure end-inspiratory lung volume during brief apnea (20-40 seconds) to quantify hyperinflation, as this correlates better with complications than peak pressure 5

Ventilatory Pattern Adjustments for Airflow Obstruction

For patients with severe airflow obstruction experiencing hyperinflation:

• Reduce minute ventilation if clinically tolerable - normocapnic ventilation often causes dangerous hyperinflation in these patients 5
• Increase expiratory time by decreasing respiratory rate or increasing inspiratory flow 5
• Reduce tidal volume to minimize dynamic hyperinflation 5
• Monitor for hypotension as a sign of excessive hyperinflation affecting venous return 5

Critical Pitfalls to Avoid

• Never ignore rising peak pressures assuming they only reflect flow - always assess plateau pressure to distinguish airway resistance from decreased compliance 4, 6
• Do not rely on peak airway pressure alone to assess for barotrauma risk - measure plateau pressure and consider end-inspiratory lung volume in obstructive disease 5
• Avoid heated humidified circuits in favor of HME filters to reduce viral load in the circuit, but monitor closely for filter obstruction 1
• Never disconnect the circuit without first ensuring adequate sedation, pausing the ventilator, and clamping the endotracheal tube 1
• Check tube depth during sedation holds as there is increased displacement risk when patients become more active 1

Monitoring Strategy

• Continuously monitor pressure waveforms in real-time, particularly during volume-controlled ventilation where pressure is the dependent variable 6
• Analyze flow waveforms during pressure-controlled ventilation to detect changes in respiratory mechanics 6
• Use pressure-volume and flow-volume loops to assess dynamic trends in compliance and resistance 6
• Consider telemonitoring only in resource-limited settings; direct bedside assessment is preferred when resources are adequate 3