Operating room cost for coronary artery bypass graft procedures: does experience or severity of illness matter?

Very few studies have addressed the magnitude of the effect of the condition of the patients and the surgical volume on possible cost savings in coronary artery bypass grafting (CABG). The objectives of this study were to analyse and compare the costs of the CABG operating room (OR) between two hospitals, and to examine the effect of surgical volume and severity of illness on the OR costs.

The charts of patients who were diagnosed with coronary artery disease and who underwent CABG at two acute tertiary care hospitals in 2004 were reviewed retrospectively. Data on patient demographics, length of stay (LOS) and the American Society of Anesthesiologists Physical Status (ASAPS) score were extracted from the patient records. Cost information was obtained from detailed billing charges and from the financial accounting divisions of the hospitals.

The high-volume hospital consumed fewer resources than the low-volume hospital (US$5411 vs. US$6407). The age of the patients, surgical volume, operating hours and LOS were associated with the OR cost. Patient age and ASAPS score, hospital, and surgical volume were associated with LOS. Patient age, the number of diseased vessels, doctor volume and pump used or not were positively associated with the operation time. The LOS and the operation time may be the mediators of the relationship between the ASAPS score and cost, and may moderate the association of volume with cost.

This study supports the saying that 'practice makes perfect'. The knowledge and experience of the surgeons and the hospital management team are equally important in the supply of health services to patients with varying severity of illness, and are needed to maintain the competitive position of a hospital.