Technical issues: a guide for when non-invasive ventilation is failing
| Problem | Cause(s) | Solution (s) |
|---|---|---|
| Ventilator cycling independently of patient effort | Inspiratory trigger sensitivity is too highExcessive mask leak | Adjust trigger Reduce mask leak |
| Ventilator not triggering despite visible patient effort | Excessive mask leakInspiratory trigger sensitivity too low | Reduce mask leakAdjust triggerFor NM patients consider switch to PCV |
| Inadequate chest expansion despite apparent triggering | Inadequate tidal volume | Increase IPAP. In NM or chest wall disease consider longer Ti |
| Chest/abdominal paradox | Upper airway obstruction | Avoid neck flexionIncrease EPAP |
| Premature expiratory effort by patient | Excessive Ti or IPAP | Adjust as necessary |
EPAP = expiratory positive airway pressure; IPAP = inspiratory positive airway pressure; NIV = non-invasive ventilation; NM = neuromuscular; PCV = pressure-controlled ventilation; Ti = duration of inspiration. Reproduced with permission from Davidson AC, Banham S, Elliott M et al. BTS/ICS guideline for the ventilatory management of acute hypercapnic respiratory failure in adults. Thorax 2016;71 (Suppl 2):ii1–35.6