OBJECTIVE To characterize the course of open-heart surgery patients who require prolonged (greater than 72 hrs) mechanical ventilation and to define the role and timing of tracheostomy. METHODS Retrospective review. METHODS Cardiac surgery ICU and surgery wards at a university hospital. METHODS All open-heart surgery patients during an 18-month period from January 1988 to July 1989 (n = 581). From this group, 58 patients (9.9%) required prolonged mechanical ventilation. METHODS Study patients (n = 58) were followed through the course of intubation and/or tracheostomy until they were extubated, left the hospital on ventilation, or died. RESULTS End-points for mortality and complications were determined. Overall mortality rate was 43% in the patients who required prolonged mechanical ventilation. Twenty-eight percent of the 58 patients died within the first 14 days. Of those patients who survived, 55% required an endotracheal tube only and were extubated in less than 14 days; 45% of the patients required tracheostomy. Of those patients who required tracheostomy, five (26%) were eventually extubated, seven (37%) remained mechanically ventilated, and seven (37%) died. The complication rate for endotracheal tubes was 65%; the complication rate for tracheostomy was 37%. CONCLUSIONS Open-heart surgery patients requiring prolonged mechanical ventilation are a desperately ill subset of cardiac surgery patients. Those patients who survive are either extubated in less than 14 days or require prolonged mechanical ventilation beyond that point. In our opinion, patients should be given 1 wk to recover and one trial of weaning from the ventilator. If this approach fails, then they should undergo elective tracheostomy.