Society of Cardiovascular Anesthesiologists

Readmission to the Intensive Care Unit After "Fast-Track" Cardiac Surgery: Risk Factors and Outcome

Kogan A, Cohen J, Raanani E et al. Ann Thorac Surg 2003;76:503-7

Reviewed by: E. Andrew Ochroch, MD

University of Pennsylvania

The authors undertook a prospective cohort study to determine the rate of return to the ICU after "Fast-Track" management during cardiac surgery and ICU recovery. All patients undergoing cardiopulmonary bypass were observed. Anesthetic management consisted of fentanyl 20 - 40 mcg/kg, midazolam 0.15 - 0.2 mg/kg, pancuronium, and isoflurane. Patients were cooled to 30§C and then rewarmed to 37§C. Upon admission to the ICU the decision to proceed with early extubation was determined based on established protocol: No transplant or aortic reconstruction cases, no intra-aortic balloon pump, requirement for increasing vasopressors or oxygen, and severe COPD. Criteria for weaning from the ventilator also included absence of significant bleeding (< 100 ml/hr), absence of significant arrhythmia, adequate urine output (> 1ml/kg/hr). Patients spent 4 to 6 hours in the ICU after extubation and were discharged to a cardiothoracic ward.

Two thousand five hundred and fifty patients underwent cardiac surgery. Sixty-eight were excluded due to transplant or aortic reconstruction; a further 869 were excluded based on their ICU presentation. Of the 1,613 patients who entered the "Fast-Track", 53 (3.3%) required readmission: 25 within 24 hours, 15 between 24 and 48 hours, and 13 after 48 hours. There was prolonged ICU stay upon readmission of 105.6 (SD 180) hours. Six of these patients died.

The group that was readmitted was identifiable based on a higher 2000 Bernstein-Parsonnet risk estimate (20.1 ñ10 versus 12.9 ñ8.4, p<0.05), age > 70 years, female sex, and LVEF < 30%. Pulmonary problems accounted for 43.4% of the readmissions, with almost half of these presenting within the first 24 hours. Since these authors did not have a step-down unit, it may be possible to decrease the rate of return by transferring patients to a care area with 1:3 nursing coverage, rather than 1:6 as did these authors. Otherwise, newer monitoring technology like continuous telemetered pulse oxymetry may be useful in this cohort due to their high risk of pulmonary complications.

Overall, the low readmission rate justified the safety and effectiveness of the "Fast-Track" protocol after heart surgery. However, in high risk patients, safety needs to be balanced with economic necessity. While age > 70 as a cutoff has not been universally supported to predict risk, LVEF <30% has been shown to be a consistent risk factor for post-operative complications. The prospective use of the 2000 Bernstein-Parsonnet risk estimate would seem to be useful, but probably only in ICUs that are fully computerized to be able to develop this score in real time.

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Readmission to the Intensive Care Unit After "Fast-Track" Cardiac Surgery: Risk Factors and Outcome