[Comparison of three ventilatory modes during immediate postoperative transfer of cardiac surgical patients]

Compare three ventilatory strategies during the immediate postoperative transfer of cardiac surgical patient.

Prospective, comparative and observational study.

After approval by our local ethical committee, 330 patients undergoing on-pump cardiac surgery were consecutively included. Patients suffering from chronic obstructive pulmonary disease, exhibiting intraoperative hypoxemia or requiring nitric oxide were excluded. The ventilatory mode was left at the discretion of the anesthesiologist and included: controlled mechanical ventilation (FiO(2)=1, N=124) or (FiO(2)=0.6, N=106), and manual ventilation using rebreathing bag (N=100). A blood gas analysis was performed immediately prior to connecting patient at ventilator at the arrival in ICU.

The mean duration of transfer was 3.9+/-1.4 min. Invasive pressure monitoring was used in all patients. The pulse oxymetry and electrocardiogram were respectively used in 78% and 24% of patients. PaO(2) values less than 100 mmHg and those more than 300 mmHg were more frequently found in patients ventilated by rebreathing bag (42%) and mechanical ventilation FiO(2)1 (52%), respectively. No significant difference was found between groups regarding PaCO(2) values.

When rebreathing bag is used for transfer in ICU, severe decrease in PaO(2) may be observed. In absence of intraoperative hypoxemia, a mechanical ventilation with FiO(2)0.6 seems to be the most suitable ventilatory strategy for such short immediate postoperative transfer.