Most likely to benefit – COPD or hypercapnic acute cardiogenic pulmonary edema
Caution in severely hypoxemic patients
- Delay in endotracheal intubation should not occur because of NIPPV
- Favorable response is usually apparent in the first 2 hours
- Key is appropriately selecting the right patients for NIPPV
2004 Cochrane database review showed decrease in mortality, decreased intubation, and faster clinical improvement associated with NIPPV.
Dangers of inadequate ventilation
- Transdiaphragmatic pressure generation is high -> risk of respiratory muscle fatigue
Acute cardiogenic pulmonary edema
Decreases work of breathing and improves cardiovascular function
- Decreases LV afterload
- Reduces RV and LV preload
3CPO study showed that in patients with clinical dx of CPE (RR > 30, pH < 7.35, CXR w/ edema) randomized to NIPPV or standard oxygen tx had improved physiologic outcomes with NIPPV, but no difference in intubation rates and 7 and 30 day mortality.
- Crossover – There was a high incidence of crossover (~15%) from the standard oxygen group. This could make argument that higher rates of intubation could have happened in standard oxygen group.
- Sick patients excluded – Severely ill patients w/ need for lifesaving intervention were excluded.
- CPAP vs. PSV+PEEP – Similar outcomes (re: intubation, mortality, clinical changes) between the two modes of NIPPV.
Hypoxemic respiratory failure
Difference between CPAP and PSV+PEEP
- Early benefit with dyspnea and oxygenation
- But, no difference with ETI, mortality, or ICU LOS
- CPAP alone not recommended in mild to severe ARDS
- Multiple RCTs (Martin 2000, Ferrer 2003) found benefits regarding intubation and mortality. Though importantly these studies had heterogenous patient populations with ARDS from multiple etiologies.
- Despite some benefit seen in the studies above, there have been high rates of NIPPV failure in PNA and severe hypoxemia patients (Meduri 1996, Jolliet 2001, Domenighetti 2002, Antonelli 2001).