Background

• Noninvasive positive pressure ventilation (NPPV) is one of the most frequently utilized methods of respiratory support in the emergency department
• NIPPV is efficacious in the initial treatment of COPD exacerbations, hypercapnic respiratory failure, and patients with cardiogenic pulmonary edema
• NIPPV has been proven to avoid invasive mechanical ventilation

When Does it Fail?

• In an observational study of 54 ICU patients at a single tertiary center treated with NPPV for acute lung injury (ALI) 38 patients failed NPPV
• The most common reasons were shock, metabolic acidosis and severe hypoxemia
• In another multicenter study across eight ICUs, predictors of NPPV were ARDS, higher illness severity score, pneumonia or failure to improve after one hour of treatment (defined as failure to achieve PaO2:FiO2>200)
• The literature signals towards failure in patients with older age, sepsis, and multiorgan failure

Conclusions

• Unsurprisingly, NIPPV seems to have higher failure rates in patients who are critically ill with severe, refractory hypoxemia and in patients with pathology unlikely to resolve quickly (such as pneumonia, septic shock/multi-organ failure)
• Intubation and mechanical ventilation may be better choices in these patients

References:

Rana, S. et al. Failure of non-invasive ventilation in patients with acute lung injury: observational cohort study. Crit Care 10, R79 (2006).

International Consensus Conferences in Intensive Care Medicine: Noninvasive Positive Pressure Ventilation in Acute Respiratory Failure. 163, 283–291 (2001).

Antonelli, M, et al. A comparison of noninvasive positive-pressure ventilation and conventional mechanical ventilation in patients with acute respiratory failure. NEJM 339(7) 429-435 (1998)

Antonelli, M. et al. Predictors of failure of noninvasive positive pressure ventilation in patients with acute hypoxemic respiratory failure: a multi-center study. Intens Care Med 27, 1718–1728 (2001).