Optimization of mechanical ventilation support following cardiac surgery.

BACKGROUND: Mechanical ventilation (MV) is essential in the management of patients that underwent cardiac surgery and cardiopulmonary bypass. It has been demonstrated that MV dependence is directly related to morbidity incidence and ICU length of stay, with a strong impact on economic cost. Therefore identification of measures that can reduce MV interval, may reduce the incidence of respiratory complications and length of hospitalization. The aim of this study was to identify weaning indexes and adopt a weaning algorithm in order to optimize ventilatory support after cardiac surgery. METHODS: Forty-nine patients with low and medium Higgins risk score, who underwent, between February and November 1999, elective surgery at our Institution, were enrolled in this study. All patients were randomized into 2 groups: Group I (weaning group - 24 patients), extubated with the aid of a weaning protocol, and Group II (control group - 25 patients), extubated with conservative weaning, dependent on the physician's subjective clinical judgment. All patients were successfully weaned from mechanical support. RESULTS: Intubation time was significantly lower in Group I than Group II and "Fast Track Recovery" group (p=0.05). ICU length of stay was also significantly lower in Group I (p=0.03). Analysis of weaning indexes did not show cut-off points predictive of successful weaning, except for PaO2/FiO2 ratio, which was higher in Group I (p=0.02). CONCLUSIONS: These results confirm that the use of a weaning algorithm enables the MV interval and hospital length of stay to be shortened, suggesting that it should be used in the management following cardiac surgery.