Long-term outcomes after viral pneumonia caused by influenza A (H1N1)

Abstract

Objectives: To evaluate the sequelae of viral (H1N1) pneumonia at 3,6,12 months follow-up.

Methods: We evaluated 22 survivors of the influenza A (H1N1) virus pneumonia at 3, 6, and 12 months after discharge.

At each visit, the patient was interviewed; underwent a physical examination, pulmonary-function testing, chest radiography, 6MWT and a quality-of-life evaluation.

Results: At discharge all patients had abnormal chest radiographs, DLCO values below 80% of predicted (50,7±21,6%) and 6MW distance was shorter than in normal controls in the same age-groups (498,5±34,2m).

There was significant difference between the intubated and non-intubated patients in lung function (FVC 57,7±10,6% vs 101,9±10,2% p=0,01 TLC 72,0±7,1% vs 106,5±7,6% p=0,01 DLCO 29,5±3,9% vs 64,9±5,8% p=0,01 respectively) but there were no significant difference with respect to their in exercise capacity and quality-of-life evaluation at discharge.

After the discharge between the intubated and non-intubated patients revealed a continuing significant difference in lung diffusing capacity at 3, 6, and 12 months (DLCO 62,1±5,8% vs 85,7±3,2% p=0,01 DLCO 67,8±5,2% vs 89,0±2,2% p=0,01 DLCO 67,9±7,4% vs 92,2±1,5% p=0,01 respectively).

After discharge 11 patients received oral N-acetilcystein 1800 mg/day and inhaled heparin (15-20 000/day) for 3 months. At 3 months there was no significant difference in DLCO (71,5±17,4% vs 83,4±7,8% p=0,3) and a distance 6MWT (533±12,6m vs 618±39,4m p=0,08) in favor of patients recieved N-acetilcystein and inhaled heparin.

Conclusions: Our results show significant impairment of DLCO in survivors of the influenza A (H1N1) virus pneumonia. There was significant difference between the intubated and non-intubated patients.