Effectiveness of noninvasive positive pressure ventilation in the treatment of acute respiratory failure in severe acute respiratory syndrome

Abstract

Objectives: To study the effectiveness of noninvasive positive pressure ventilation (NIPPV) in the treatment of acute respiratory failure (ARF) in severe acute respiratory syndrome (SARS), and the associated infection risk.

Methods: All patients with the diagnosis of probable SARS admitted to a regional hospital in Hong Kong from March 9 to April 28, 2003, and who had SARS-related respiratory distress complications were recruited for NIPPV usage. The health status of all health-care workers working in the NIPPV wards was closely monitored, and consent was obtained to check serum for coronavirus serology. Patient outcomes and the risk of SARS transmission to health-care workers were assessed.

Results: NIPPV was applied to 20 patients (11 male patients) with ARF secondary to SARS. Mean age was 51.4 years, and mean acute physiology and chronic health evaluation II score was 5.35. Coronavirus serology was positive in 95% (19 of 20 patients). NIPPV was started 9.6 days (mean) from symptom onset, and mean duration of NIPPV usage was 84.3 h. Endotracheal intubation was avoided in 14 patients (70%), in whom the length of ICU stay was shorter (3.1 days vs 21.3 days, p < 0.001) and the chest radiography score within 24 h of NIPPV was lower (15.1 vs 22.5, p = 0.005) compared to intubated patients. Intubation avoidance was predicted by a marked reduction in respiratory rate (9.2 breaths/min) and supplemental oxygen requirement (3.1 L/min) within 24 h of NIPPV. Complications were few and reversible. There were no infections among the 105 health-care workers caring for the patients receiving NIPPV.

Conclusions: NIPPV was effective in the treatment of ARF in the patients with SARS studied, and its use was safe for health-care workers.

Figure 1

Respiratory parameters during the course of NIPPV. Difference between respiratory rate at 24 h and baseline: nonintubated, − 9.2 ± 4.0; intubated, 4.0 ± 13/3 (p = 0.026). Difference between oxygen supplement requirement at 24 h and baseline: nonintubated, − 3.1 ± 2.5; intubated, − 0.2 ± 2.2 (p = 0.012). LPM = liters per minute.