Noninvasive ventilation: experience at a community teaching hospital

Objective:To describe our hospital's experience with noninvasive positive p ressure ventilation (bilevel positive airway pressure; BiPAP) for patients with respiratory failure (RF). Design: Retrospective, observational study. Setting: A 300-bed community teaching hospital. Methods: Medical records were analyzed for physiologic and outcome variable s for all patients who received BiPAP for RF between January 1994 and Decem ber 1996. Results: Eighty patients with a mean (+/- S. E.) age of 71.5 +/- 1.3 years and APACHE II score of 17.2 +/- 0.6 received BiPAP for RF during the study period. Thirty-one patients received BiPAP for hypoxemic RF, 25 for acute h ypercapnic RE 9 for chronic hypercapnic RE 10 for postextubation RF and 5 c ould not be categorized. BiPAP success was defined as no need for invasive ventilation. BiPAP was successful in 47 of 75 cases that could be classifie d; all BiPAP successes lived whereas 18 of 28 BiPAP failures died. In the o verall cohort, BiPAP success was associated with a lower ICU length of stay (5.8 +/- 0.9 versus 10.6 +/- 1.4 days, p < 0.01). The duration of BiPAP de pendency in successful cases was 35.3 +/- 6.7 h. BiPAP was successful in 20 of 25 patients with acute hypercapnic RF and in 15 of 31 patients with hyp oxemic RE The risk of BiPAP failure was significantly greater (risk ratio = 2.6, 95 % CI = 1.1-6.1) for patients with hypoxemic than for those with hy percapnic RE BiPAP success was marked by increased PaO2/FIO2 in patients wi th hypoxemic RF and by increased pH and reduced PCO2 in patients with hyper capnic RE BiPAP use was also successful in 8 of 10 patients who developed R F within 48 h of endotracheal extubation. Conclusions: BiPAP is highly effective in selected patients with RF during routine use in a community teaching hospital. The success rate is higher am ongst patients presenting with hypercapnic than amongst those with hypoxemi c RF and BiPAP failure is associated with an increased likelihood of in-hos pital mortality. BiPAP may also be used successfully to temporize patients who develop RF in the period following endotracheal extubation. The duratio n of BiPAP dependency (35 h in this study) was shorter than in previous tri als, and, though this is speculative, may have been minimized by our perfor ming a trial of unassisted breathing each day.