Implementing a protocol to optimize blood use in a cardiac surgery service: results of a pre-post analysis and the impact of high-volume blood users.

Abstract

Blood transfusions are a common and costly intervention for cardiac surgery patients. Evidence suggests that a more restrictive transfusion strategy may reduce costs and transfusion-related complications without increasing perioperative morbidity and mortality. A transfusion-limiting protocol was developed and implemented in a cardiovascular surgery unit. Over a 5-year period, data were collected on patient characteristics, procedures, utilization of blood products, morbidity, and mortality, and these were compared before and after the protocol was implemented. After the protocol was put in place, fewer patients required transfusions (38.2% vs. 45.5%, p = 0.004), with the greatest reduction observed in postoperative blood use (29.1% vs. 37.2%, p = 0.001). In-hospital morbidity and mortality did not increase. When patients who received transfusions were stratified by procedure, the protocol was most effective in reducing transfusions for patients undergoing isolated coronary artery bypass grafting (CABG; 4.09 units vs. 2.51 units, p = 0.009) and CABG plus valve surgery (10.32 units vs. 4.77 units, p = 0.014). A small group of patients were disproportionate recipients of transfusions, with approximately 6% of all patients receiving approximately half of the blood products. A protocol to limit transfusions decreased the proportion of cardiothoracic surgery patients who received blood products. A very small group of patients received a large number of transfusions, and within that group the observed mortality was significantly higher than in the general patient population. Current protocols cannot possibly account for these patients, and this should be considered when analyzing the performance of protocols designed to reduce unnecessary transfusions.