Resource utilization in on- and off-pump coronary artery surgery: factors influencing postoperative length of stay--an experience of 1,746 consecutive patients undergoing fast-track cardiac anesthesia

Abstract

Objective: The purpose of the present investigation was to examine factors influencing resource utilization in patients undergoing on-pump coronary artery bypass graft and off-pump coronary artery bypass (OPCAB) graft surgery at a major university hospital. The resources examined were time to extubation, packed red blood cell (PRBC) transfusion, intensive care length of stay (ICULOS), preoperative and postoperative length of stay (PLOS), and total length of stay (LOS).

Design: Observational study of consecutive patients undergoing on- and off-pump coronary artery bypass surgery.

Setting: Tertiary care cardiac referral center.

Participants: One thousand seven hundred forty-six consecutive male and female patients undergoing primary coronary artery bypass graft (CABG) surgery over a period of 3 years (1999-2001). Eight hundred eighty-one patients underwent CABG with pump, and 865 patients underwent off-pump coronary artery bypass (OPCAB) surgery.

Interventions: None.

Measurements and main results: The mean time to extubation after surgery was 7.4 hours for on-pump patients and 5.8 hours for the OPCAB group (p<or=0.001); 73.7% of patients on pump received PRBC transfusion as compared with 48.6% of the OPCAB group (p<or=0.001). The mean ICULOS for the on-pump group was 1.6 days and 1.4 days for the OPCAB group (p=0.006). PLOS was 6.5 days for the on-pump group and 5.6 days for the OPCAB group (p<or=0.001). Mean total LOS was 9.7 days for the on-pump group and 8.8 days for the OPCAB group (p<or=0.001). PLOS is correlated with several clinical and demographic ariables. Linear and logistic regression models were used to assess the effects of on/off pump on PLOS. Use of pump is significantly correlated with increased PLOS (p<or=0.001, Kendalls correlation), and pump use is strongly associated with transfusion (odds ratio=2.95, p<or=0.001), which in turn is a determinant of PLOS. There were no significant differences between the on- and off-pump groups in the incidence of postoperative complications except for bleeding requiring reexploration and ventilatory support for more than 72 hours. Incidence of bleeding was 3.3% in the on-pump group and 1.7% in the OPCAB group (p=0.038). In the on-pump group, 3% of patients required >72 hours to postoperative tracheal extubation compared with 1.5% in the OPCAB group (p=0.041). Hospital mortality was 2.7% for the on-pump group and 1.0% for the OPCAB group (p=0.010).

Conclusion: The authors found that patients undergoing on-pump CABG have significantly longer time to tracheal extubation, increased blood use, longer ICULOS, PLOS, and total LOS and higher in-hospital mortality, which would translate into significant differences in the expenses associated with these 2 surgical approaches to coronary surgery.