THE USE OF NONINVASIVE POSITIVE PRESSURE VENTILATION IN THE EMERGENCYDEPARTMENT - RESULTS OF A RANDOMIZED CLINICAL-TRIAL

Objective: To determine whether the use of noninvasive positive pressu re ventilation (NPPV) in the emergency department (ED) will reduce the need for tracheal intubation and mechanical ventilation. Design: Rand omized, controlled, prospective clinical trial. Setting: ED of Barnes- Jewish Hospital, a university-affiliated teaching hospital. Patients: Twenty-seven patients meeting a predetermined definition of acute resp iratory distress requiring hospital admission. Interventions: Conventi onal medical therapy for the various etiologies of acute respiratory d istress and the application of NPPV. Measurements and results: The pri mary outcome measure was the need for tracheal intubation and mechanic al ventilation. Secondary outcomes also assessed included hospital mor tality hospital length of stay, acquired organ system derangements, an d the utilization of respiratory care personnel. Sixteen patients (59. 3%) were randomly assigned to receive conventional medical therapy plu s NPPV, and 11 patients (40.7%) were randomly assigned to receive conv entional medical therapy without NPPV, The two groups were similar at the time of randomization in the ED with regard to demographic charact eristics, hospital admission diagnoses, and severity of illness. Trach eal intubation and mechanical ventilation was required in seven patien ts (43.8%) receiving conventional medical therapy plus NPPV and in fiv e patients (45.5%) receiving conventional medical therapy alone (relat ive risk=0.96; 95% confidence interval=0.41 to 2.26; p=0.930). There w as a trend towards a greater hospital mortality rate among patients in the NPPV group (25%) compared to patients in the conventional medical therapy group (0.0%) (p=0.123). Among patients who subsequently requi red mechanical ventilation, those in the MPPV group had a longer time interval from ED arrival to the start of mechanical ventilation compar ed to patients in the conventional medical therapy group (26.0+/-27.0 h vs 4.8+/-6.9 h; p=0.055). Conclusions: We conclude that the applicat ion of NPPV in the ED may delay tracheal intubation and the initiation of mechanical ventilation in some patients with acute respiratory dis tress. We also demonstrated that the application of NPPV was associate d with an increased hospital mortality rate. Based on these preliminar y observations, larger clinical investigations are required to determi ne if adverse patient outcomes can be attributed to the early applicat ion of NPPV in the ED. Additionally, improved patient selection criter ia for the optimal administration of NPPV in the ED need to be develop ed.