Factors Associated With Prolonged Mechanical Ventilation Following Coronary Artery Bypass Surgery

To identify the typical duration ofpostoperative mechanical ventilation following coronary artery bypassgraft surgery (CABG), and to identify risk factors for prolongedpostoperative ventilation. Retrospective studyof 4,863 consecutive patients using univariate and multivariatesurvival analysis to identify independent risk factors. Saint Thomas Hospital, Nashville, TN, a 575-bed, academically affiliated, regional referral hospital specializing incardiovascular diseases. All patientsundergoing CABG in our hospital from January 1, 1996, to December 31,1997. None. Duration of mechanical ventilation and mortality weremeasured. More than 94% of the patients were extubated in the first 3days following surgery, 4% more were extubated from postoperative days4 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 withthe highest incidence of prolonged postoperative mechanical ventilationand for operative mortality. The Society of Thoracic Surgeons-predictedmortality estimate was the best single independent predictor forprolonged postoperative ventilation. Typically, patients can be expected to be extubated within 3 days after, CABG. Certain preoperative comorbidities, especially preoperativecardiac or respiratory instability, are predictive of prolongedpostoperative mechanical ventilation.