NONINVASIVE PRESSURE SUPPORT VENTILATION IN PATIENTS WITH ACUTE RESPIRATORY-FAILURE - A RANDOMIZED COMPARISON WITH CONVENTIONAL THERAPY

The benefit of noninvasive pressure support ventilation (NIPSV) in avo iding the need for endotracheal intubation and reducing morbidity and mortality associated with endotracheal intubation was evaluated in 41 patients who presented with acute respiratory failure not related to c hronic obstructive pulmonary disease (COPD). Patients were randomly as signed to receive conventional therapy (n=20) or conventional therapy plus NIPSV (n=21). NIPSV was delivered to the patient by a face mask c onnected to a ventilator (Puritan-Bennett 7200a) set in inspiratory pr essure support (IFS) mode. The mean levels of IFS, positive end-expira tory pressure (PEEP), and fraction of inspired oxygen (FIO2 were respe ctively 15 +/- 3 cm H2O, 4 +/- 2 cm H2O, and 57 +/- 22%. The rate of e ndotracheal intubation (62 vs 70%, p=0.88), the length of ICU stay (17 +/- 19 days vs 25 +/- 23 days, p=0.16), and the mortality rate (33 vs 50%, p=0.46) were not different between patients treated with NIPSV a nd those treated conventionally. Post hoc analysis suggested that in p atients with PaCO2 >45 mm Hg (n=17), NIPSV was associated with a reduc tion in the rate of endotracheal intubation (36 vs 100%, p=0.02), in t he length of ICU stay (13 +/- 15 days vs 32 +/- 30 days, p=0.04), and in the mortality rate (9 vs 66%, p=0.06). We conclude that NIPSV is of no benefit when used systematically in all forms of acute respiratory failure not related to COPD. A subgroup of patients, characterized by acute ventilatory failure and hypercapnia, may potentially benefit fr om this therapy and further studies are needed to focus on this aspect .