The impact of blood conservation on outcomes in cardiac surgery: is it safe and effective?

BACKGROUND: Increasing evidence shows that perioperative blood transfusion in cardiac surgery is associated with increased postoperative morbidity and mortality and decreased long-term survival. Tolerance of "permissive anemia" is an important element of perioperative blood conservation strategy. The safety of tolerating perioperative anemia has been a significant deterrent for widespread application of blood conservation. This study examines whether blood conservation is equally safe or superior to the common practice of transfusion in cardiac surgery. METHODS: The total study population consisted of 32,449 patients who underwent isolated coronary artery bypass surgery from June 2000 until December 2004 with complete data from 17 institutions in the State of New Jersey. Englewood Hospital and Medical Center (EH) has a well-established blood conservation program. Five hundred eighty-six EH patients (blood conservation cohort) were compared with a propensity score-matched cohort of 586 patients from the other New Jersey institutions (OH-M) representing the common practice of transfusion. Outcomes were classified as very serious complications, serious complications, or neither (no very serious complication or serious complication). Analysis consisted of McNemar tests and multiple logistic regression. RESULTS: Fewer patients were transfused at EH compared with OH-M (10.6% versus 42.5%; p < 0.0001). Englewood Hospital had 5 (0.8%) deaths versus 15 (2.5%) in the OH-M group (p = 0.02). Of the EH patients, 11.1% experienced a very serious complication or serious complication versus 18.7% in the OH-M cohort (p = 0.0002). Transfusion was associated with an increased risk of an adverse outcome in both cohorts (EH: odds ratio, 7.3; 95% confidence interval, 3.7 to 14.4 versus OH-M: odds ratio, 4.6; 95% confidence interval, 2.8 to 7.7). CONCLUSIONS: Blood conservation is safe and effective in reducing transfusions. Tolerance of perioperative anemia, which is one of the main components of blood conservation, does not increase the risk of complications or death in cardiac surgery. Avoidance of transfusion reduces the risk of complications. This study further solidifies the relationship between transfusion and adverse outcome in cardiac surgery.

Postoperative blood loss and transfusion associated with use of Hextend in cardiac surgery patients at a blood conservation center.

BACKGROUND: Hydroxyethyl starch (HES) solutions are readily available colloids, but their widespread use is shadowed by controversies surrounding their effects on bleeding. This retrospective study was conducted to evaluate the relationship between Hextend (HEX; Hospira, Inc.) doses of 1 to 20 mL/kg and allogeneic transfusion and 24-hour chest tube drainage (CTD) in cardiac surgeries at a blood conservation center. STUDY DESIGN AND METHODS: After institutional review board approval, data on 748 patients undergoing coronary artery bypass grafting (CABG), valve, or combined CABG and valve surgeries were collected. Cases not receiving HEX (due to contraindications, e.g., renal failure, bleeding diathesis) or receiving more than 20 mL per kg HEX, not accepting transfusions, or requiring more extensive surgery were excluded, and the remaining 621 cases were analyzed. RESULTS: Overall transfusion rate and mean CTD were 12.7 percent and 460.4 mL, respectively. Patients who received transfusions received more HEX (10.8 mL/kg vs. 9.8 mL/kg; p = 0.043) but HEX per kg was not associated with higher transfusion rates in multivariate analysis (p = 0.077). HEX per kg was associated with CTD in both uni- and multivariate analyzes (p < 0.001) with 1.66 percent increase in CTD for every 1 mL per kg increase in HEX. CONCLUSIONS: Although HEX was associated with transfusion in univariate analysis and with CTD in uni- and multivariate analysis, the former was no longer significant when adjusted for other predictors of transfusion in our selected patient population at a blood conservation center. The clinical significance of the observed increase in CTD remains undetermined. To minimize transfusion and bleeding in these patients, it is recommended that HEX be used in amounts of not more than 20 mL per kg together with point-of-care coagulation tests and other blood conservation strategies.

Use of the Hemobag for modified ultrafiltration in a Jehovah's Witness patient undergoing cardiac surgery.

Modified ultrafiltration is an important technique to concentrate the patient's circulating blood volume and the residual whole blood in the extracorporeal circuit post-cardiopulmonary bypass. The Hemobag system is a device cleared by the US Food and Drug Administration and represents a novel and safe modification of traditional modified ultrafiltration systems. It is quick and easy to operate by the perfusionist during the hemoconcentration process. Hemoconcentration is accomplished by having the Hemobag "recovery loop" circuit separate from the extracorporeal circuit. This allows the surgeons to continue with surgery, decannulate, and administer protamine simultaneously while the Hemobag is in use. The successful use of the Hemobag in a Jehovah's Witness patient has not been previously described in the literature. This case report describes how to set up and operate the Hemobag in a Jehovah's Witness patient undergoing cardiac surgery that requires an extracorporeal circuit.

Application of biological glue in repair of intracardiac structural defects.

BACKGROUND: BioGlue (Cryolife Inc, Kennesaw GA) was introduced as an alternative tissue sealant. Its most common application has been in repairs of acute dissections of the aorta. There is no reported experience with its use in the repair of intracardiac structural defects. METHODS: In 5 patients BioGlue was used as an adjunct in repairs of complex intracardiac structural defects. It was used during patch repair of posterior mitral annular defects in 2 patients and aortic annular defect in 1 patient in the presence of active endocarditis. It was also used in 1 patient with a chronic atrioventricular groove pseudoaneurysm following mitral valve replacement, and in 1 patient during repair of a postinfarction posterior ventricular septal rupture. RESULTS: There were no hospital or late deaths. Immediate intraoperative transesophageal echocardiography and late follow-up echocardiography documented complete and durable repair of all defects without recurrence. At follow-up all patients are in New York Heart Association class I-II, 6 to 29 months postoperatively. No patient has suffered late complications or exhibited signs of glue embolization. CONCLUSIONS: BioGlue was found to be an effective adjuvant to the standard techniques used for the repair of intracardiac structural defects of various etiologies. Long-term follow-up is recommended to determine its long-term safety in this application.

Predictors of transfusion requirements for cardiac surgical procedures at a blood conservation center.

BACKGROUND: Previous studies defining perioperative risk factors for allogeneic transfusion requirements in cardiac surgery were limited to highly selected cardiac surgery populations or were associated with high transfusion rates. The purpose of this study was to determine perioperative risk factors and create a formula to predict transfusion requirements for major cardiac surgical procedures in a center that practices a multimodality approach to blood conservation. METHODS: We performed an observational study on 307 consecutive patients undergoing coronary artery bypass grafting, valve, and combined (coronary artery bypass grafting and valve) procedures. An equation was derived to estimate the risk of transfusion based on preoperative risk factors using multivariate analysis. In patients with a calculated probability of transfusion of at least 5%, intraoperative predictors of transfusion were identified by multivariate analysis. RESULTS: Thirty-five patients (11%) required intraoperative or postoperative allogeneic transfusions. Preoperative factors as independent predictors for transfusions included red blood cell mass, type of operation, urgency of operation, number of diseased vessels, serum creatinine of at least 1.3 mg/dL, and preoperative prothrombin time. Intraoperative factors included cardiopulmonary bypass time, three or fewer bypass grafts, lesser volume of acute normovolemic hemodilution removed, and total crystalloid infusion of at least 2,500 mL. The derived formula was applied to a validation cohort of 246 patients, and the observed transfusion rates conformed well to the predicted risks. CONCLUSIONS: A multimodality approach to blood conservation in cardiac surgery resulted in a low transfusion rate. Identifying patients' risks for transfusion should alter patient management perioperatively to decrease their transfusion rate and make more efficient use of blood resources.

Multidisciplinary management of a Jehovah's Witness patient for the removal of a renal cell carcinoma extending into the right atrium.

PURPOSE: To highlight the management of a Jehovah's witness surgical patient presenting for cardiopulmonary bypass (CPB) and deep hypothermic circulatory arrest. CLINICAL FEATURES: A 47-yr-old male, Jehovah's Witness, with renal cell carcinoma was admitted for left radical nephrectomy and excision of tumour thrombus extending into the junction of the inferior vena cava (IVC) and right atrium (RA). The preoperative goals were to maximize red blood cell mass, delineate the extent of tumour extension and develop a surgical plan incorporating blood conservation strategies to minimize blood loss. A midline abdominal incision was made to optimize removal of the non-caval portion of the tumour from the intra-abdominal region. CPB and deep hypothermic circulatory arrest were instituted to aid in removing the tumour from the IVC and RA. Intraoperative blood conservation strategies included the use of acute normovolemic hemodilution, antifibrinolytics, cell salvage, point-of-care monitoring of heparin and protamine blood concentrations, leukocyte-depleting filter, and meticulous surgical techniques. The patient was successfully weaned from CPB and was transported to the cardiothoracic intensive care unit without complication. The patient was discharged home one week after the operation with a hemoglobin of 10.2 g x dL(-1) and a hematocrit of 31.2%. CONCLUSION: Multiple blood conservation techniques were employed to manage this Jehovah's Witness patient through complex cardiac surgery, which was previously denied to him at other institutions. The successful outcome of this patient, while respecting the right to refuse allogeneic blood products, is a result of a multidisciplinary collaboration as well as the application of established blood conservation techniques.