THE EPIDEMIOLOGY OF HEMORRHAGE RELATED TO CARDIOTHORACIC OPERATIONS

OBJECTIVE: To define the epidemiology, risk factors, and unadjusted co st of hemorrhages related to cardiothoracic operations. STUDY DESIGN: We conducted two case-control studies to evaluate the risk of hemorrha ge following cardiothoracic operations. The definition of hemorrhage r equired one of the following: reoperation for bleeding, postoperative loss of greater than 800 mL of blood over 4 hours, or surgeon-diagnose d excessive intraoperative bleeding. SETTING: The cardiothoracic surge ry service of a university hospital. RESULTS: Of 511 patients undergoi ng cardiothoracic operations, 93 (18%) met the definition of hemorrhag e. In the first case-control study, 3 (14%) of 21 cases and 0 of 42 co ntrols died (odds ratio [OR], 15.0; 95% confidence interval [CI95], 1. 18-191.55). Compared with controls, cases received significantly more packed red blood cells intraoperatively (OR 1.18/100 mL; CI95, 1.01-1. 38), and significantly more platelets (OR, 3.26/100 mL; CI95, 1.47-7.2 6) and fresh frozen plasma (OR 1.73/100 mL; CI95 1.05-.84) in the inte nsive-care unit. Cases were more likely than controls to receive prota mine postoperatively (OR, 3.74; CI95, 1.27-11.02). Previous sternotomy , preoperative aspirin or heparin, and preoperative laboratory values did not predict bleeding. The median unadjusted hospital cost was $3,4 58 higher for patients who suffered hemorrhage than for controls. To d ecrease costs, hetastarch (acquisition cost $45/500 mL) was substitute d for albumin (acquisition cost $76/100 mL) in the pump priming soluti on (estimated possible cost savings, $7,000-$53,000/year). Because hem orrhage rates increased subsequently, we conducted a second case-contr ol study that identified patient age (P=.02) and use of greater than 5 mL/kg of hetastarch (OR, 1.82) as risk factors for hemorrhage. The co st of treating hemorrhages exceeded all estimates of possible cost sav ings ($7,000-$53,000 per year). CONCLUSIONS: Our definition of hemorrh age identified patients who required increased volumes of blood produc ts and who had an increased crude mortality rate and a higher unadjust ed cost of hospitalization. Patient age and hetastarch use were risk f actors for hemorrhage. Efforts to save money by substituting less expe nsive products inadvertently may increase costs by increasing the prob ability of perioperative adverse events.