Prolonged mechanical ventilation after cardiac surgery: Outcome and predictors
Prolonged mechanical ventilation after cardiac surgery is a serious complication that warrants search for new treatment strategies. Our objective was to identify patients still requiring mechanical ventilation 3 days after the operation and those successfully weaned by day 10 to avoid needless and potentially hazardous interventions, such as tracheostomy.Methods:
All consecutive patients still mechanically ventilated on day 3 after cardiac surgery were included in a prospective observational cohort. Patients' preoperative, intraoperative, and postoperative data were recorded. Logistic regression analysis was used to identify factors associated with successful weaning from mechanical ventilation by postoperative day 10.Results:
Among 2620 patients who underwent cardiac surgery, 163 were still receiving ventilatory assistance on day 3. By day 10, 50 (31%) patients had been successfully weaned, 78 (48%) were still receiving mechanical ventilation, and 35 (21%) had died. Multivariable regression analysis retained 6 day-3 factors associated with successful weaning (odds ratio): urine output 500 mL/24 hours or greater (16.47), Glasgow coma score of 15 (9.75), arterial bicarbonates 20 mmol/L or greater (6.09), platelet count 100 g/L or greater (3.18), patients without inotropic support with epinephrine/norepinephrine (2.84), and absence of lung injury (2.40). The area under the receiver operating characteristics curve for the simple score based on this model's β-coefficients was 0.84 (95% confidence intervals, 0.78-0.91). Depending on the threshold chosen for this scoring system, only 3% to 17% of the patients would have received a needless intervention.Conclusions:
A simple score based on postoperative day-3 physiologic parameters might help intensivists early identify patients with a strong likelihood of success in rapid weaning from mechanical ventilation and therefore prevent needless procedures aimed at reducing duration of mechanical ventilation and related complications.