Non-invasive positive pressure ventilation in pneumonia outside Intensive Care Unit: An Italian multicenter observational study

Abstract

Background and objective: Non-Invasive Ventilation (NIV) represents a standard of care to treat some acute respiratory failure (ARF). Data on its use in pneumonia are lacking, especially in a setting outside the Intensive Care Unit (ICU). The aims of this study were to evaluate the use of NIV in ARF due to pneumonia outside the ICU, and to identify risk factors for in-hospital mortality.

Methods: Prospective, observational study performed in 19 centers in Italy. Patients with ARF due to pneumonia treated outside the ICU with either continuous positive airway pressure (CPAP) or noninvasive positive pressure ventilation (NPPV) were enrolled over a period of at least 3 consecutive months in 2013. Independent factors related to in-hospital mortality were evaluated.

Results: Among the 347 patients enrolled, CPAP was applied as first treatment in 176 (50.7%) patients,NPPV in 171 (49.3%). The NPPV compared with CPAP group showed a significant higher PaCO₂ (55 [47-78] vs 37 [32-43] mmHg, p < 0.001), a lower arterial pH (7.30 [7.21-7.37] vs 7.43 [7.35-7.47], p < 0.001), higher HCO3- (28 [24-33] vs 24 [21-27] mmol/L, p < 0.001). De-novo ARF was more prevalent in CPAP group than in NPPV group (86/176 vs 31/171 patients,p < 0.001). In-hospital mortality was 23% (83/347). Do Not Intubate (DNI) order and Charlson Comorbidity Index (CCI) ≥3 were independent risk factors for in-hospital mortality.

Conclusions: Outside ICU setting, CPAP was used mainly for hypoxemic non-hypercapnic ARF, NPPV for hypercapnic ARF. In-hospital mortality was mainly associated to patients' basal status (DNI status, CCI) rather than the baseline degree of ARF.

Keywords: Continuous positive airway pressure; Emergency medicine; Noninvasive ventilation; Pneumonia; Respiratory insufficiency.