A one-year follow-up study of patients survived after ALI / ARDS caused by influenza A / H1N1

Abstract

Summary. The study analyzed long-term consequences of acute lung injury / acute respiratory distress syndrome (ALI / ARDS) caused by influenza A / H1N1 and effects of long-term treatment with N-acetylcysteine (NAC) on clinical and functional recovery of survived patients. This was an open, prospective, 12-month study involved 22 patients survived from ALI / ARDS caused by influenza A / H1N1. The patients' lung function, arterial blood gases, physical tolerance in 6-min walking test (6MWT) and computed tomography (CT) of the lungs were monitored in 3, 6, and 12 months after discharge. During the follow-up, all lung function parameters improved: FVC, TLC, and DLCO increased by 28.7 %, 17.5 % and 31.4 %, respectively (p < 0.05 for all). In a year after discharge, DLCO < 80 %pred. was found in 23 % of patients. At 12 months, the mean 6MWT distance increased from 454 Ѓ} 37 to 568 Ѓ} 47 m (р = 0.002). Significant improvement was noted in CT findings and 41% of patients had quite normal lung CT at 12 months. Therapy with NAC (n = 11) has led to more rapid improvement in DLCO (76.3 Ѓ} 11.8 %pred. vs 63.0 Ѓ} 10.6 %pred. in controls; р = 0.012) and 6MWT distance (533 Ѓ} 42 m vs 490 Ѓ} 46 m, respectively; р = 0.033) at 3 months. Therefore, patients survived from ALI / ARDS caused by influenza A / H1N1 demonstrated significant recovery of lung function, gas exchange, lung CT picture and physical tolerance but in some of them, persistent disorders of lung function (mainly in DLCO) and lung CT have been still found at 1 year after discharge. Treatment with NAC allowed more rapid improvement in DLCO and exercise tolerance.