No, Pressure Support Ventilation Should Not Be Used During Full Neuromuscular Blockade
Pressure support ventilation (PSV) requires spontaneous breathing effort from the patient to trigger and cycle breaths—this is fundamentally incompatible with complete neuromuscular blockade, which eliminates all respiratory muscle activity. When a patient is fully paralyzed with neuromuscular blocking agents, they cannot initiate breaths, making PSV ineffective and potentially dangerous.
Why This Combination Fails
PSV is a patient-triggered, patient-cycled mode that depends on:
- The patient's inspiratory effort to trigger the ventilator
- Ongoing respiratory drive to maintain breathing
- Diaphragmatic activity to cycle off the breath
When you administer a neuromuscular blocking agent, you eliminate the neuromuscular transmission needed for these functions. The patient becomes apneic and cannot interact with the ventilator in PSV mode 1.
Appropriate Ventilation During Neuromuscular Blockade
When using NMBAs, you must switch to controlled mechanical ventilation modes such as:
- Volume control ventilation (VCV)
- Pressure control ventilation (PCV)
- Airway pressure release ventilation (APRV)
These modes do not require patient effort and the ventilator delivers mandatory breaths independent of patient triggering 2, 1.
The Exception: Partial Neuromuscular Blockade
There is emerging evidence for a nuanced approach using partial (not complete) neuromuscular blockade during assisted ventilation modes. One proof-of-concept study demonstrated that titrated rocuronium to achieve partial blockade could facilitate lung-protective ventilation during neurally adjusted ventilatory assist (NAVA) while maintaining some diaphragm activity 3. However, this approach:
- Requires careful titration to maintain partial diaphragmatic function
- Uses specialized modes like NAVA, not standard PSV
- Remains investigational and is not standard practice
- Demands continuous monitoring with train-of-four assessment
Clinical Algorithm for NMBA Use in ARDS
Following the 2020 ICM guidelines 2:
For Mild ARDS:
- Avoid NMBA if lung-protective ventilation achievable with light sedation
For Moderate-to-Severe ARDS:
- First attempt lung-protective ventilation with light sedation
- If unsuccessful, try judicious deep sedation with intermittent NMBA boluses
- Only use continuous NMBA infusion (up to 48 hours) if:
- Persistent hypoxemia despite above measures
- Patient-ventilator dyssynchrony preventing lung protection
- Elevated plateau pressures despite optimization
- Requiring prone positioning
When NMBA infusion is initiated:
- Switch to controlled ventilation mode immediately
- Ensure adequate deep sedation (to prevent awareness during paralysis) 1, 4
- Consider train-of-four monitoring as part of comprehensive assessment 2, 1
- Target duration ≤48 hours 2, 5
Critical Safety Considerations
The most important pitfall is inadequate sedation during paralysis. Guidelines universally emphasize that NMBA use is inseparable from adequate sedation for ethical reasons—patients must not experience awareness while paralyzed 6, 4. Recent data shows that 95% of patient-days with NMBA use included both sedation and analgesia, but 4.7% did not receive guideline-concordant care 4.
Additional concerns with NMBA use include:
- ICU-acquired weakness (though recent trials show less concern than previously thought)
- Prolonged mechanical ventilation duration 7
- Need for structured physiotherapy regimen 1
Bottom line: Full neuromuscular blockade requires controlled ventilation modes. PSV is only potentially compatible with carefully titrated partial blockade in specialized circumstances, which remains investigational.