Early extubation of patients undergoing elective coronary artery bypass surgery is a trend in surgical practice. Mandatory Minute Ventilation (MMV) is a mode of ventilation that guarantees set minute ventilation but allows an automatic transition from mechanical support to spontaneous breathing. Automatic Tube Compensation (ATC) is a mode extension that provides compensation for the flow-dependent endotracheal tube resistance during both inspiration and expiration. Objective: To evaluate the safety and efficacy of a computer-driven MMV/ATC (Drager Medical, Telford, PA) as a weaning method in the post-operative open-heart patient.
The study was a prospective trial performed in a 12-bed Open Heart Unit (OHU) of a 600-bed tertiary referral community hospital. Stable, uncomplicated patients were randomized to either MMV/ATC or an OHU protocol that entails spontaneous breathing trials. The two groups were compared for weaning intolerance, comfort of weaning, length of ventilatory support, OHU length of stay (LOS), and hospital LOS.
Between 10/14/02 and 8/15/03, 250 consecutive patients were randomized. There were no differences in age, gender, pre-operative severity score, pump time, cross-clamp time, transfusion requirement, fluid administration, total operative time, intra-operative doses of benzodiazapines or narcotics. Time from last dose of a sedative was shorter in the MMV group (25.4 vs. 31.7 min; p=0.002). There were no differences in failed weaning or liberation. For those successfully liberated, time to extubation was shorter in the MMV group compared to the control group (239.2 vs. 265.9 min; p<0.001). There was no difference between groups for comfort, OHU LOS or hospital LOS.
MMV/ATC is well tolerated and potentially quicker as a weaning method in post-operative cardiac patients.
MMV/ATC should be considered in the development of protocols for weaning post-operative cardiac patients.
D.E. Ray, None.