Right ventricular function and high-frequency positive-pressure ventilation during coronary artery bypass grafting.

The hemodynamic and respiratory consequences of two modes of ventilation, conventional intermittent positive-pressure ventilation with a frequency of 10 cycles/min and high-frequency positive-pressure ventilation at 70 cycles/min were investigated before and after cardiopulmonary bypass in 6 patients having coronary artery bypass grafting. All patients were adequately ventilated with each mode. During prebypass and postbypass periods, the group with high-frequency ventilation had significantly lower peak airway pressures (p = 0.0001) and mean airway pressure (p less than 0.05). There were, however, no significant differences in right ventricular performance or pulmonary vascular resistance between the two modes of ventilation. No significant differences in other cardiovascular and respiratory variables were noted. High-frequency positive-pressure ventilation, with the advantage of quieter operating conditions and improved surgical access, can be safely applied when meticulous operation or hemostasis is required or during dissection of the internal mammary artery.