[Outcomes of severe pandemic influenza A/H1N1/2009]

To study the outcomes of severe pandemic influenza A/H1N1/2009.

The study enrolled 24 patients, including 8 males and 16 females (10 of whom were pregnant), aged 17 to 58 years, with a laboratorily verified diagnosis of pandemic influenza A/H1N1/2009, treated at the intensive care unit for the significant symptoms of acute respiratory failure (RF). Real-time RT-PCR was used to verify the diagnosis. Organs and tissues from deceased patients were histologically studied; chest computed tomography, body plethysmography, fibrobronchoscopy, breath test, and 6-minute walk test were performed in the late period.

Within the first 30 days, a fatal outcome caused by therapy-resistant progressive RF was observed in 33% of the patients with pandemic influenza treated at the intensive care unit. Diffuse alveolar damage caused by influenza virus, which gives rise to hyaline membranes, underlies RF. Lung tissue fibrosis formed in recovered patients.

The severity of pandemic influenza A/H1N1/2009 was determined by massive bilateral pneumonia, interstitial (alveolar) pulmonary edema, formation of diffuse bilateral lung fibrosis at the outcome of severe virus pneumonia (acute respiratory distress syndrome) with a decrease in vital and diffusing capacities, thereby generating a need to follow up this patient category and, possibly, to elaborate special rehabilitation programs.