Prehospital reversal of profound respiratory acidosis and hypercapnic coma by non-invasive ventilation: a report of two cases

BACKGROUND: In chronic obstructive pulmonary disease (COPD) patients with acute respiratory failure (ARF), non-invasive ventilation (NIV) is generally recommended and has proven its benefits by reducing endotracheal intubation (ETI) rates, intensive care unit (ICU) admissions, complications, and mortality. Choosing between immediate ETI or NIV trial is often difficult when such patients present with an altered mental status. Some guidelines recommend avoiding NIV when consciousness is impaired given the risk of aspiration, and some authors suggest that a pH < 7.25 is highly predictive of NIV failure. Though clinical response to a well-adjusted NIV treatment can be both swift and spectacular, these contraindications probably encourage physicians to proceed to immediate ETI. Some studies indeed report that NIV was not even considered in as many as 60% of patients who might have benefited from this therapy, though ETI related complications might have been avoided had NIV been successfully applied. CASE PRESENTATION: We report two cases of ARF in COPD patients who were successfully treated by NIV in prehospital setting and avoided ETI despite contraindications (altered mental status with a Glasgow Coma Scale < 8) and failure risk factors (severe respiratory acidosis with pH < 7.25). CONCLUSION: In COPD patients presenting ARF, NIV trial could be considered even when relative contraindications such as an altered level of consciousness or a severe respiratory acidosis are present.