A simple clinical model for planning transfusion quantities in heart surgery

Abstract

BackgroundPatients undergoing heart surgery continue to be the largest demand on blood transfusions. The need for transfusion is based on the risk of complications due to poor cell oxygenation, however large transfusions are associated with increased morbidity and risk of mortality in heart surgery patients. The aim of this study was to identify preoperative and intraoperative risk factors for transfusion and create a reliable model for planning transfusion quantities in heart surgery procedures.MethodsWe performed an observational study on 3315 consecutive patients who underwent cardiac surgery between January 2000 and December 2007. To estimate the number of packs of red blood cells (PRBC) transfused during heart surgery, we developed a multivariate regression model with discrete coefficients by selecting dummy variables as regressors in a stepwise manner. Model performance was assessed statistically by splitting cases into training and testing sets of the same size, and clinically by investigating the clinical course details of about one quarter of the patients in whom the difference between model estimates and actual number of PRBC transfused was higher than the root mean squared error.ResultsTen preoperative and intraoperative dichotomous variables were entered in the model. Approximating the regression coefficients to the nearest half unit, each dummy regressor equal to one gave a number of half PRBC. The model assigned 4 units for kidney failure requiring preoperative dialysis, 2.5 units for cardiogenic shock, 2 units for minimum hematocrit at cardiopulmonary bypass less than or equal to 20%, 1.5 units for emergency operation, 1 unit for preoperative hematocrit less than or equal to 40%, cardiopulmonary bypass time greater than 130 minutes and type of surgery different from isolated artery bypass grafting, and 0.5 units for urgent operation, age over 70 years and systemic arterial hypertension.ConclusionsThe regression model proved reliable for quantitative planning of number of PRBC in patients undergoing heart surgery. Besides enabling more rational resource allocation of costly blood-conservation strategies and blood bank resources, the results indicated a strong association between some essential postoperative variables and differences between the model estimate and the actual number of packs transfused.

Evaluation of the use of blood in surgeries as a tool to change patterns for requesting blood product reserves

“…However, among the specialties, cardiac surgeries had the highest transfusion rate, in which 50% of the patients in this specialty were transfused. This result was also reported by Stanworth et al in 2002 14, who observed higher transfusion rates in cardiac and orthopedic procedures; however, studies have shown that the demand for and use of RBCs in cardiac surgeries may vary between medical teams and between institutions 15.…”

Effects of Blood Transfusion on Hospital Mortality During Coronary Artery Bypass Grafting

“…Çalışmamızda intraoperatif parametrelerden KPB süresi ve kros klemp süresi istatistiksel olarak anlamlı bulundu. Literatürde benzer şekilde destekleyen raporlar mevcut (3,(13)(14)(15)(16)(17) . Bu parametrelerin ayrıca transfüzyona olan ihtiyacı artıracağı da bilinmektedir.…”

Effectiveness of a cardiac surgery–specific transfusion protocol

“…While the majority of patients undergoing elective cardiac surgery will not receive allogenic blood products, a substantial number of patients consume disproportionately high amounts of blood products . Especially prolonged cardiopulmonary bypass (CPB) times, reoperations, urgent surgeries, and complex cardiac surgical procedures are associated with excessive blood loss and attendant transfusion of blood products …”