Management of severe respiratory failure following influenza A H1N1 pneumonia

The use of non-invasive ventilation (NIV) in severe hypoxemic respiratory failure (PaO₂/FIO₂ ‰¤250) due to H1H1 virus pneumonia is controversial. In this prospective study, we aimed to assess the efficacy of NIV in avoiding endotracheal intubation and to identify predictors of success or failure. Nineteen patients with H1N1 viral pneumonia had severe respiratory failure (PaO₂/FIO₂ ratio ‰¤250). Five patients with PaO₂/FIO₂ lower than 150 and simplified acute physiology score (SAPS II) lower than 34 underwent NIV and were admitted to the Intensive Care Unit and received NIV as first-line therapy. NIV failed in 2 of the 14 patients but had a good outcome in 12. None of the patients treated with NIV died. The duration of NIV was 5.0±1.9 days and the hospital stay was 11.3±1.2 days. The average PaO₂/FIO₂ ratio after 1 h of NIV was 239.1+38.7. No patient had multi-organ failure. PaO₂/FIO₂ ratio after 1 h and SAPS II at admission were independent variables correlated with the success of NIV. In our study, NIV was successful in 12 of the 14 patients (85.7%) and this is one of the highest success rates in the literature. In our opinion, the reason for these results is the strict selection of patients with severe respiratory failure (PaO₂/FIO₂ ratio ‰¥150) and the strict following of predictors of success for NIV such as SAPS II of 34 or lower and PaO₂/FIO₂ ratio of 175 or lower after 1 h of NIV. Clinicians should be aware of pulmonary complications of influenza A H1N1 and strictly select the patients to undergo NIV. NIV could have an effective and safe role in reducing the high demand for critical care beds, particularly during the pandemic.