Original article
Effects of Alveolar Recruitment on Arterial Oxygenation in Patients After Cardiac Surgery: A Prospective, Randomized, Controlled Clinical Trial

https://doi.org/10.1053/j.jvca.2006.01.003Get rights and content

Objective: Pulmonary atelectasis and hypoxemia remain considerable problems after cardiac surgery. The objective of this study was to determine the efficacy of consecutive vital capacity maneuvers (C-VCMs) to improve oxygenation in patients after cardiac surgery.

Study Design: Randomized, controlled clinical trial.

Setting: Tertiary referral teaching center.

Participants: Ninety-five patients requiring elective cardiac surgery with cardiopulmonary bypass (CPB).

Intervention: Patients were randomly allocated to either C-VCM or control groups. In the C-VCM group, lung inflation at pressure of 35 cmH2O was sustained for 15 seconds before separation from CPB and at 30 cmH2O for 5 seconds after admission to the intensive care unit (ICU).

Measurements and Main Results: The primary outcome was the ratio of arterial oxygen tension to inspired oxygen fraction measured at the following predetermined time intervals: after induction of anesthesia, 15 minutes after separation from CPB, after admission to the ICU, after 3 hours of positive-pressure ventilation, after extubation, and before ICU discharge. C-VCM resulted in better arterial oxygenation extending from the immediate postoperative period to approximately 24 hours after surgery at the time of ICU discharge. There were no significant adverse events related to C-VCM application.

Conclusion: C-VCM is an effective method to reduce hypoxemia associated with the formation of atelectasis after cardiac surgery with CPB.

Section snippets

Methods

After institutional review board approval, informed consent was obtained from all participants. Patients undergoing elective primary coronary artery bypass graft surgery with CPB or single-valve repair/replacement surgery were randomly allocated to 1 of 2 groups: group C-VCM (consecutive vital capacity maneuver) and group C (controls). Computer-generated randomization code in blocks of 4 was used for group assignment. Patients undergoing emergency or redo surgery; patients requiring chest

Results

A total of 104 patients were enrolled in the study. Nine patients were excluded (5 from R-VCM and 4 from control groups); 5 patients underwent resternotomy to control postoperative bleeding, 2 patients required prolonged mechanical ventilation because of cardiogenic shock requiring intra-aortic balloon pump, and 2 suffered perioperative stroke. The remaining 95 patients completed the study and were followed until discharge from the hospital. Both groups were similar with respect to their

Discussion

The main finding of this study is that consecutive VCM resulted in better arterial oxygenation extending from the immediate postoperative period to approximately 24 hours after surgery, at the time of ICU discharge.

Impaired arterial oxygenation after cardiac surgery is a well-recognized problem.1, 2, 3 Multiple mechanisms are responsible for acute lung injury after CPB. Oxidant-mediated lung damage as a sequela of ischemia-reperfusion injury; adhesion and sequestration of neutrophils;

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