Oxygenation and static compliance is improved immediately after early manual hyperinflation following myocardial revascularisation : a randomised controlled trial

Abstract

Question: Are oxygenation and static compliance improved immediately after manual hyperinflation following myocardial revascularisation? Does this lead to earlier extubation and shorter hospital stay? Does it reduce postoperative pulmonary complications? Design: Randomised controlled trial with concealed allocation, blinded assessment and intention-to-treat analysis. Participants: Fifty-five patients who underwent myocardial revascularisation. Intervention: After an hour in recovery, the experimental group received manual hyperinflation with positive end expiratory pressure followed by suction while the control group received suction only. Outcome measures: Oxygenation (PaO₂ in mmHg) and static lung compliance (in ml/cmH₂O) were measured immediately after suction. Time to extubation (in minutes) and length of hospital stay (in days) were collected and postoperative pulmonary complications were confirmed by X-ray. Results: PaO₂ was 11.7 mmHg (95% CI 9.4 to 14.0) greater in the experimental group while static compliance was 8.5 ml/cmH₂0 (95% CI 6.4 to 10.6) greater than in the control group. The experimental group was extubated 76 minutes (95% CI 24 to 128) earlier than the control group but did not have a shorter length of stay (mean difference 0.5 days, 95% CI –0.2 to 1.2). The relative risk of postoperative pulmonary complications was no greater (RR 0.57, 95% Cl 0.20 to 1.60) in the experimental group than in the control group. Conclusion: The group that received early manual hyperinflation had markedly better oxygenation and static compliance as well as shorter mechanical ventilation times than the control group. The length of hospital stay and incidence of postoperative pulmonary complications were similar in the two groups.