Determinants of intensive care unit length of stay after coronary artery bypass graft surgery

Objective The purpose of this study is to identify independent preoperative, intraoperative, and postoperative determinants of intensive care unit (ICU) length of stay in patients undergoing coronary artery bypass graft (CABG) surgery and to evaluate the usefulness of a mortality risk scoring system, the Parsonnet score, as a prognostic indicator of ICU length of stay after CABG.Methods A prospective nonrandomized sample of 109 consecutive patients was enrolled before CABG and followed prospectively until ICU discharge. Multivariate linear regression was used to identify factors independently associated with ICU length of stay.Results One preoperative variable (Parsonnet score) and 4 postoperative variables (length of intubation, presence of arrhythmias, early hemodynamic instability, and 12-hour fluid balance) explained 45.6% of the variance in ICU length of stay. Intraoperative variables were not independent correlates of ICU length of stay. Classification as "extremely high" risk by Parsonnet scoring (score 20) yielded a positive predictive value of 84% for ICU stay >1 day. Negative predictive value was 42.8%.Conclusions Preoperative and postoperative variables explained a large portion of the variance in ICU stay after CABG. Although the Parsonnet score was not helpful in identifying patients who require only a short ICU stay, it may help clinicians screen for patients likely to require stays >1 day and plan appropriate use of resources in the ICU.