Faculty Bibliography

Safety and efficacy concerns of allogeneic blood transfusions and their impact on patient outcomes and associated staggering costs and restricted supply have fueled the quest for other modalities and strategies to reduce use of blood components. Patient blood management focuses on multidisciplinary and multimodal preventive measures to reduce or obviate the need for transfusions and ultimately to improve the clinical outcomes of patients. Patient blood management strategies can be applied at every stage of care to surgical and nonsurgical patients, and they generally fall under one of these three categories (the so-called pillars of blood management): optimizing hematopoiesis and appropriate management of anemia, minimizing bleeding and blood loss, and harnessing and optimizing physiological tolerance of anemia through employing all available modalities while treatment is initiated. Several tools and modalities are available to address each of these pillars. Examples include hematinic agents, systemic and topical hemostatic agents, autotransfusion, and blood-sparing perfusion and surgical techniques. Additionally, changes in practice of clinicians (e.g., adherence to restrictive, evidence-based transfusion strategies with emphasis on physiologic indications for transfusion, minimization of iatrogenic blood loss, and adequate planning) play an important role in patient blood management. Emerging evidence supports that appropriate use of these strategies as part of a multimodal program is a safe and effective way of reducing allogeneic transfusions and improving patient outcomes.

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.

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.

BACKGROUND: Geographic location is not acknowledged as a stratifying factor that can directly affect drug potency, because drugs are still licensed with the same recommended dose for different geographic regions. The aim of the current study was to compare the potency and duration of action of rocuronium bromide in 54 patients in three countries with different life habits, diet, and ambient conditions, namely white Austrians, white North Americans, and Han Chinese in China. METHODS: Neuromuscular block of six consecutive 50-microg/kg rocuronium incremental doses followed by 300 microg/kg was evaluated using the Relaxometer mechanomyograph (Groningen University, Groningen, Holland). Dose-response curves were created using log-dose-probit transformation. The authors compared rocuronium bromide ED50, ED90, and ED95 (effective doses required for 50%, 90%, and 95% first twitch depression, respectively) as well as Dur25 and Dur0.8 (times from last incremental dose administration until 25% first twitch and 0.8 train-of-four ratio recovery, respectively) in patients of the three countries. RESULTS: Rocuronium ED50, ED90, and ED95 were significantly higher in Austrian patients (258 +/- 68, 530 +/- 159, and 598 +/- 189 microg/kg) and Chinese patients (201 +/- 59, 413 +/- 107, and 475 +/- 155 microg/kg) compared with American patients (148 +/- 48, 316 +/- 116, and 362 +/- 149 microg/kg, respectively). Dur25 and Dur0.8 were significantly shorter in Austrian patients (22.3 +/- 5.5 and 36.9 +/- 12.8 min) and Chinese patients (30.4 +/- 7.5 and 45.7 +/- 15.9 min) compared with American patients (36.7 +/- 8.5 and 56.2 +/- 16.7 min, respectively). CONCLUSIONS: The authors demonstrated a significant difference in rocuronium potency and duration of action among patients in the three countries. Larger studies are required for determining dosage recommendations for different geographic regions.

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.

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.