Pannu, Sonal R

Abstract Rationale The management of severe and refractory hypoxemia in critically ill adult patients is practice based. Variability across individual practitioners and institutions is not well documented. Objectives To conduct a nationwide survey of critical care physicians in the United States regarding accepted definitions and management strategies for severe and refractory hypoxemia. Methods A web-based survey was distributed to a stratified random sample of adult intensivists listed in the American Medical Association Physician Masterfile. The survey was generated by using a mixed-methods approach. Measurements and Main Results: In the survey, 4,865 e-mails were sent and 791 (16.3%) were opened. Among those who opened the e-mail message, 50% (n = 396) responded, representing 8.1% of total surveys sent. Seventy-two percent stated that their institutions lacked a protocol for identification and management of severe or refractory hypoxemia in the setting of acute respiratory failure. While the majority of respondents used low-Vt ventilation (81%), high positive end-expiratory pressure (86%), recruitment maneuvers (89%), and either bolus or infusion neuromuscular blockade (94%), there was marked variability in the use of specific rescue strategies as tier 1 or 2 interventions: prone position (27.8% vs. 47.8%, respectively), extracorporeal membrane oxygenation (2.3% vs. 51.2%, respectively), airway pressure release ventilation (49% vs. 34.5%, respectively), inhaled vasodilators (30.1% vs. 40%, respectively), and high-frequency oscillatory ventilation (7.8% vs. 40%, respectively). The variability was partly explained by providers’ expertise with particular rescue strategies (77.7%), advance directives (70.1%), the training of allied health staff (62.3%), and institutional availability (53.8%). Conclusions U.S. adult critical care physicians predominantly employ lung-protective ventilation for severe hypoxemia. A wide variation in other rescue strategies is noted, which is partly explained by user expertise and availability. Less than 30% institutions have formal protocols for management of refractory hypoxemia.

BACKGROUND: Subjects with severe hypoxemic respiratory failure have shown a high mortality in previous studies. METHODS: All adult ICU patients requiring mechanical ventilation from 2005 to 2010 at Mayo Clinic were screened for severe hypoxemia (Murray lung injury score of ≥ 3). Extracorporeal membrane oxygenation, prone positioning, high-frequency oscillatory ventilation (HFOV), and inhaled vasodilators were considered as rescue strategies. A propensity-based scoring was created for the indication or predilection to use each strategy. A model was created to evaluate the association of each rescue strategy with hospital mortality. RESULTS: Among 1,032 subjects with severe hypoxemia, 239 subjects received some form of rescue strategy (59 received a combination of therapies, and 180 received individual therapies). Inhaled vasodilators were the most common, followed by HFOV. Rescue strategies were used in younger subjects with severe oxygenation deficits. Subjects receiving rescue strategies had higher mortality and longer ICU stays. None of the strategies individually or in combination showed a significant association with hospital mortality after adjusting covariates by propensity scoring. Adjusted Odds ratios and respective 95% CI were as follows: HFOV 0.67 (0.35–1.27), extracorporeal membrane oxygenation 0.63 (0.18–1.92), prone position 1.07 (0.49–2.28), and inhaled vasodilators 1.17 (0.78–1.77). CONCLUSIONS: In this retrospective comparative effectiveness study, there was no association of rescue strategies with hospital mortality in subjects with severe hypoxemia.