Study objectives: To identify the typical duration of
postoperative mechanical ventilation following coronary artery bypass
graft surgery (CABG), and to identify risk factors for prolonged
Design: Retrospective study
of 4,863 consecutive patients using univariate and multivariate
survival analysis to identify independent risk factors.
Setting: Saint Thomas Hospital, Nashville, TN, a 575-bed,
academically affiliated, regional referral hospital specializing in
Patients: All patients
undergoing CABG in our hospital from January 1, 1996, to December 31,
results: Duration of mechanical ventilation and mortality were
measured. More than 94% of the patients were extubated in the first 3
days following surgery, 4% more were extubated from postoperative days
4 to 14, and almost 2% were receiving ventilation for > 14 days.
Those risk factors that reflect preoperative medical instability,
especially cardiac or respiratory insufficiency, were associated with
the highest incidence of prolonged postoperative mechanical ventilation
and for operative mortality. The Society of Thoracic Surgeons-predicted
mortality estimate was the best single independent predictor for
prolonged postoperative ventilation.
Typically, patients can be expected to be extubated within 3 days after
CABG. Certain preoperative comorbidities, especially preoperative
cardiac or respiratory instability, are predictive of prolonged
postoperative mechanical ventilation.