Transfusion and surgery

Hemostasis in burn surgery--a review

Over the past 30 years, techniques of early excision and grafting along with enhancement of critical care have significantly improved survival following burn injury. Despite these advancements, large volume blood loss associated with surgical intervention continues to be a challenging aspect of burn surgery. This review article will examine the methods of limiting blood loss during surgical procedures.

Anemia of critical illness

Anemia of critical illness, a commonly encountered clinical situation, is hematologically similar to that of chronic anemia, except that the onset is generally sudden. The etiology is usually multifactorial, occurring as a consequence of direct inhibitory effects of inflammatory cytokines, erythropoietin deficiency, blunted erythropoietic response, blood loss, nutritional deficiencies, and renal insufficiency. Although anemia is not well tolerated by critically ill patients, aggressive treatment of anemia can be just as detrimental as no treatment. Different types of anemia may coexist in a patient in the intensive care unit, making diagnosis and differentiation among these anemias complex, therefore requiring good diagnostic skills. Although several therapeutic options are available to treat anemia, critically ill patients often receive a transfusion, and yet, most recent studies indicate that blood transfusions in critically ill patients are associated with worse outcomes, including higher morbidity and mortality. These studies have generated interest in the administration of exogenous erythropoietin and iron therapy. Unfortunately, the accurate determination of iron status can be a rather difficult task, an undertaking that is made even more difficult by the presence of comorbid conditions that can affect the commonly used parameters for guiding iron therapy. The use of erythropoiesis-stimulating agents is rapidly gaining acceptance, although they also present potential problems of their own.

Utilization of Predonated Autologous Blood in Anterior Cervical Corpectomy and Fusion Surgery

OBJECTIVE

To determine the utilization of predonated autologous blood in patients treated with anterior cervical corpectomy and fusion (ACCF).

METHODS

Retrospective chart review of 154 patients who underwent 1, 2, or 3-level ACCF over a 6-year period was performed. Variables collected included patterns of autologous and allogenic blood use, blood loss, and hematocrit at admission and discharge from the hospital.

RESULTS

For 1-level ACCF, only 16.7% of the predonated autologous blood was used. As expected, use of predonated autologous blood increased with the number of corpectomy levels: Patients with 2 and 3-level ACCF used 29.0% and 53.4% of the predonated blood, respectively. The use of autologous blood significantly reduced the need for allogenic blood transfusion for 2 and 3-level ACCF.

CONCLUSIONS

Autologous blood was used efficiently in 3-level ACCF, and predonation is associated with decreased allogeneic blood transfusion requirement in 2 and 3-level ACCF.

Blood loss minimization and blood salvage techniques for complex spinal surgery

Several techniques to limit blood loss and salvage lost blood are available to surgeons, physicians, and personnel who treat complex spinal disorders. These techniques include red blood cell augmentation, intraoperative antifibrinolytic administration, use of topical hemostatic agents, and intraoperative blood salvage and postoperative blood salvage. A substantial amount of research has been directed toward reducing perioperative blood loss in spinal surgery. More efforts need to be directed toward effective perioperative blood management in complex spinal surgery.

Peri-operative blood management in elective orthopaedic surgery. A critical review of the literature

Blood loss during orthopaedic procedures can be extensive and the need for allogeneic blood is a common requirement. However, blood transfusion conceals a number of well-recognised risks and complications and blood products have become more expensive because of their specific preparation procedure. Surgical technique, awareness of the problem and restriction of transfusion triggers are important factors affecting the management of blood loss. Several studies have additionally shown the efficacy of epoetin injections in increasing the pre-operative haemoglobin level. On the other hand, the true benefit of pre-operative autologous donation, acute normovolemic haemodilution and COX-2 selective NSAIDs remains under dispute. Regarding the role of platelet rich plasmapheresis, fibrin sealing and anti-fibinolytic drugs more data are needed. Hypotensive epidural anaesthesia seems to be an advantageous method in minimising peri-operative blood loss. However, this is not a widely performed technique in orthopaedic surgery. In addition, post-operative blood cell saving systems after total knee or hip arthroplasty have been reported to significantly minimise allogeneic blood transfusions when compared to control groups. It can be concluded that many interventions diminish more or less allogeneic blood transfusion in elective orthopaedic surgery. Nevertheless more prospective studies are needed and appropriate algorithms should be applied in peri-operative blood loss management. This review presents an overview of the available interventions which aim to diminish the use of allogeneic blood in elective orthopaedic surgery.

Effects of Circuit Miniaturization in Reducing Inflammatory Response to Infant Cardiopulmonary Bypass by Elimination of Allogeneic Blood Products

Conventional neonatal cardiopulmonary bypass requires the use of large volumes of allogeneic blood to prevent unacceptable hemodilution. Evidence is accumulating to suggest that the use of blood products during cardiopulmonary bypass has a negative effect on clinical recovery through inflammatory side effects. This would suggest an advantage for eliminating blood use in infant cardiopulmonary bypass through circuit miniaturization. In this article, we review the data supporting this rationale and provide the results from studies in our laboratory that emphasize the benefits of circuit miniaturization.

Anemia in the long-term ventilator-dependent patient with respiratory failure

Anemia occurs in virtually all critically ill patients receiving long-term mechanical ventilation and has been associated with increased mortality and poor outcomes. Allogeneic RBC transfusions are routinely administered to critically ill anemic patients, especially during lengthy stays in ICUs or in long-term acute care facilities. Although RBC transfusions are a physiologically rational approach to raising hemoglobin levels, they may increase the risk of complications and have been associated with higher mortality in critically ill patients. Treatment with epoetin alfa, an erythropoiesis-stimulating agent, as a means of reducing transfusion requirements has been studied in the critically ill and in patients receiving long-term mechanical ventilation. Promising results have been reported, including a potential survival benefit, although larger and more definitive studies are needed in order to establish whether raising hemoglobin levels affects clinical outcomes in patients receiving mechanical ventilation.

Recombinant human erythropoietin therapy in critically ill patients: a dose-response study [ISRCTN48523317]

Introduction

The aim of this study was to assess the efficacy of two dosing schedules of recombinant human erythropoietin (rHuEPO) in increasing haematocrit (Hct) and haemoglobin (Hb) and reducing exposure to allogeneic red blood cell (RBC) transfusion in critically ill patients.

Method

This was a prospective, randomized, multicentre trial. A total of 13 intensive care units participated, and a total of 148 patients who met eligibility criteria were enrolled. Patients were randomly assigned to receive intravenous iron saccharate alone (control group), intravenous iron saccharate and subcutaneous rHuEPO 40,000 units once per week (group A), or intravenous iron saccharate and subcutaneous rHuEPO 40,000 units three times per week (group B). rHuEPO was given for a minimum of 2 weeks or until discharge from the intensive care unit or death. The maximum duration of therapy was 3 weeks.

Results

The cumulative number of RBC units transfused, the average numbers of RBC units transfused per patient and per transfused patient, the average volume of RBCs transfused per day, and the percentage of transfused patients were significantly higher in the control group than in groups A and B. No significant difference was observed between group A and B. The mean increases in Hct and Hb from baseline to final measurement were significantly greater in group B than in the control group. The mean increase in Hct was significantly greater in group B than in group A. The mean increase in Hct in group A was significantly greater than that in control individuals, whereas the mean increase in Hb did not differ significantly between the control group and group A.

Conclusion

Administration of rHuEPO to critically ill patients significantly reduced the need for RBC transfusion. The magnitude of the reduction did not differ between the two dosing schedules, although there was a dose response for Hct and Hb to rHuEPO in these patients.

Prevalence and outcomes of anemia in surgery: a systematic review of the literature

Untreated preoperative anemia and acute perioperative blood loss may add to surgical risk. To understand the prevalence of anemia in surgical patients (with a primary focus on preoperative anemia), and the impact that preexisting anemia has on transfusion rates as well as on clinical and functional outcomes, a systematic review was performed of articles published between January 1966 and February 2003. The estimates of anemia prevalence in the literature ranged widely, from 5% in geriatric women with hip fracture to 75.8% in patients with Dukes stage D colon cancer. Diagnosis of anemia was most strongly associated with an increased risk of receiving an allogeneic transfusion. In general, patients who donated autologous blood preoperatively received less allogeneic blood than those who did not donate. There was some suggestion that lower hemoglobin levels are associated with decreased survival rates, although this was not found universally. Too few studies were found that evaluated the impact of anemia on other outcomes, such as functional status and costs and resource utilization, to draw reliable conclusions. Several other factors also limited the interpretation of the data, including the lack of a uniform definition for anemia and a dearth of studies expressly designed to quantify the prevalence and impact of anemia. Establishing a uniform definition and specifically evaluating the effect of anemia on outcomes are important considerations for future study.

The CRIT Study: Anemia and blood transfusion in the critically ill—Current clinical practice in the United States*

OBJECTIVE

To quantify the incidence of anemia and red blood cell (RBC) transfusion practice in critically ill patients and to examine the relationship of anemia and RBC transfusion to clinical outcomes.

DESIGN

Prospective, multiple center, observational cohort study of intensive care unit (ICU) patients in the United States. Enrollment period was from August 2000 to April 2001. Patients were enrolled within 48 hrs of ICU admission. Patient follow-up was for 30 days, hospital discharge, or death, whichever occurred first.

SETTING

A total of 284 ICUs (medical, surgical, or medical-surgical) in 213 hospitals participated in the study.

PATIENTS

A total of 4,892 patients were enrolled in the study.

MEASUREMENTS AND MAIN RESULTS

The mean hemoglobin level at baseline was 11.0 +/- 2.4 g/dL. Hemoglobin level decreased throughout the duration of the study. Overall, 44% of patients received one or more RBC units while in the ICU (mean, 4.6 +/- 4.9 units). The mean pretransfusion hemoglobin was 8.6 +/- 1.7 g/dL. The mean time to first ICU transfusion was 2.3 +/- 3.7 days. More RBC transfusions were given in study week 1; however, in subsequent weeks, subjects received one to two RBC units per week while in the ICU. The number of RBC transfusions a patient received during the study was independently associated with longer ICU and hospital lengths of stay and an increase in mortality. Patients who received transfusions also had more total complications and were more likely to experience a complication. Baseline hemoglobin was related to the number of RBC transfusions, but it was not an independent predictor of length of stay or mortality. However, a nadir hemoglobin level of <9 g/dL was a predictor of increased mortality and length of stay.

CONCLUSIONS

Anemia is common in the critically ill and results in a large number of RBC transfusions. Transfusion practice has changed little during the past decade. The number of RBC units transfused is an independent predictor of worse clinical outcome.

Transfusion practice in the critically ill

BACKGROUND

Anemia in the critically ill patient population is common. This anemia of critical illness is a distinct clinical entity characterized by blunted erythropoietin production and abnormalities in iron metabolism identical to what is commonly referred to as the anemia of chronic disease.

FINDINGS

As a result of this anemia, critically ill patients receive an extraordinarily large number of blood transfusions. Between 40% and 50% of all patients admitted to intensive care units receive at least one red blood cell unit, and the average is close to five red blood cell units during their intensive care unit stay. There is little evidence that "routine" transfusion of stored allogeneic red blood cells is beneficial for critically ill patients. Most critically ill patients can tolerate hemoglobin levels as low as 7 mg/dL, so a more conservative approach to red blood cell transfusion is warranted.

CONCLUSION

Practice strategies should be directed toward a reduction of blood loss (phlebotomy) and a decrease in the transfusion threshold in critically ill patients.

Surgery without blood

OBJECTIVE

The principle aim of "bloodless surgery" is to minimize blood loss and to reduce or eliminate exposure to allogeneic blood transfusion. The risks associated with blood transfusions have been well documented, and it is the goal of bloodless surgery centers to avoid complications and unnecessary use of blood. Blood transfusion is a significant adjunct to perioperative resuscitation. However, we aim to elucidate different approaches to minimizing blood loss and avoiding transfusion.

DESIGN

In this document, we review the background and current status of bloodless surgery centers and then the different approaches to achieve the program goals.

FINDINGS

There is no one single universal blood conservation strategy that is applicable to all patients and populations. Factors such as preexisting disease will alter the approach; however, it is the ability of any program to form a comprehensive strategy for blood conservation that is integral to the success of any such program.

CONCLUSION

The success of a bloodless surgery program requires both teamwork and careful cooperation between the blood bank, pharmacy, administration, hematologists, surgeon, and anesthesiologist to ensure that the goals of minimizing blood loss and avoiding transfusion are met.

Perioperative blood management practices in elective orthopaedic surgery

Concern about the cost and safety of allogenic blood transfusion, including the risk of viral infection and immunosuppression, has led to refinements in and new approaches to blood conservation, including the development of transfusion practice standards and improvements in surgical practice. Preoperative autologous blood collection, the use of hemostatic agents, perioperative blood salvage, and the use of recombinant human erythropoietin (epoetin alfa) to stimulate erythropoiesis have contributed to decreased use of allogenic blood services. Development of appropriate blood management strategies to help reduce or eliminate exposure to allogenic blood requires a preoperative assessment of the likelihood of transfusion and of the risks as well as costs associated with conservation and replacement options. The informed selection of alternatives based on preoperative assessment of hematologic status, estimated blood loss, and sources for blood replacement may enhance blood management practices in major elective orthopaedic surgery.

Blood Transfusion Issues in the Critically Ill

Anemia is a common clinical problem seen in the critically ill and results in a large RBC transfusion requirement for these patients. The view that RBC transfusion is risk-free is no longer tenable today. There is the accumulating evidence that allogeneic blood transfusion is immunosuppressive. More reently, attention has focused on the age of RBCs transfused. Transfused RBCs, especially during the time period immeditely following transfusion, are not normal. The duration of RBC storage may be an important determinant of the efficacy of RBCs as oxygen carriers as well as a determinant of transusion related morbidity. Adding to the controversy about risk/benefit ratio for RBC transfusion are recent data showing that an aggressive RBC transfusion strategy may decrease the likelihood of survival in selected subpopulations of critically ill adults. The optimal hematocrit for the ICU patient remains to be determined. It seems clear that hemoglobin levels falling significantly below the “10/30” threshold can be tolerated. However, it is not clear that this is applicable to the critically ill ICU patient population. Therefore, while hemoglobin levels in the 7-10 mg/dL range are well tolerated in the “stable” “nontressed” patient, this range might not be optimal for the critcally ill patient. Conservative transfusion thresholds as well as strategies to minimize loss of blood and increase the producion of RBCs are important in the management of critically ill patients.

Blood use in lung resection for carcinoma: perioperative elective anaemia does not compromise the early outcome

OBJECTIVE

Blood transfusion may adversely affect the prognosis following surgery for non-small cell lung carcinoma (NSCLC). Conventionally by most thoracic surgeons, a perioperative haemoglobin (Hb) less than 10 g/dl has been considered a transfusion trigger. In this prospective trial we have (a) evaluated the overall blood transfusion requirements and factors associated with an increased need for transfusion and (b) in a subsequent subset of patients, tested the hypothesis that elective anaemia after major lung resection may be safely tolerated in the early postoperative period.

METHODS

A total of 198 (M/F 179/10, mean age 61.2, range 32--85 years) patients suffering from NSCLC were submitted to pneumonectomy (n = 89), bilobectomy (n = 19) and lobectomy (n = 90). A rather strict protocol was used as a transfusion strategy. The transfusion requirements were analyzed and seven parameters (gender, age > 65, preoperative Hb < 11.5 g/dl, chest wall resection, history of previous thoracotomy, pneumonectomy and total blood loss) were statistically evaluated by univariate and logistic regression analysis. Subsequently, according to the perioperative Hb level during the first 48 h, patients were divided into group A (n = 49, Hb = 8.5--10) and group B (n = 149, Hb > 10) with a view to estimate the risks of elective perioperative anaemia. Groups were comparable in terms of age, sex, type of operation performed, preoperative Hb, creatinine level, FEV1, arterial blood gases and history of heart disease.

RESULTS

The overall transfusion rate was 16%. Univariate analysis revealed that preoperative Hb < 11.5 g/dl (P < 0.01) and total blood loss (P < 0.0001) were associated with increased need for transfusion, but only the total blood loss was identified as an independent variable in multivariate analysis. Statistical analysis between groups A and B showed no significant difference regarding postoperative morbidity and mortality: atelectasis (3 vs. 6), chest infection (2 vs. 9), sputum retention requiring bronchoscopy (5 vs. 12), admission to intensive care unit (5 vs. 7), ARDS (0 vs. 3), postoperative hospital stay (7.7 +/- 2.6 vs. 9.1 +/- 3.8 days) and deaths (1 vs. 3).

CONCLUSIONS

The use of a strict transfusion strategy could help in reducing overall blood transfusion. Furthermore, a perioperative Hb of 8.5--10 g/dl could be considered safe in elective lung resections for carcinoma.

Usefulness of cord-blood harvesting for autologous transfusion in surgical newborns with antenatal diagnosis of congenital anomalies

BACKGROUND/PURPOSE

The risks of homologous transfusion and the effectiveness of predeposit autologous transfusion have been described. The authors examined the clinical usefulness of cord-blood harvesting for autologous transfusion in newborns who had congenital anomalies antenatally diagnosed that would require surgical intervention at or near the time of delivery.

METHODS

Of 112 cases of antenatal diagnosis of congenital anomalies, 50 mothers gave informed consent and enrolled in this study. Cord-blood was withdrawn immediately after clamping of the umbilical cord and was used for autologous transfusion in newborns within the first 3 days postpartum.

RESULTS

A mean of 72 +/- 54 mL of cord-blood was harvested (27 +/- 18 mL/kg). While preserving cord-blood for 3 days at 4 degrees C, no signs of clot formation or hemolysis were observed. The harvested cord-blood included plasma-free Hb ranging from 1 to 68 (13 +/- 18) mg/dL and thrombin-antithrombin III complex ranging from 2 to 273 (18 +/- 50) ng/mL. Bacteriologic examination of the stored cord-blood showed negative cultures, except for samples from 3 newborns after vaginal delivery. A mean of 46 +/- 34 mL of cord-blood was used in 26 patients for autologous transfusion. No significant complications related to cord-blood transfusion were recognized clinically.

CONCLUSIONS

Autologous cord-blood transfusion has the potential to be a useful alternative to homologous transfusion in newborns requiring surgery. Adequate collection and storage techniques for cord-blood must be developed. J Pediatr Surg 36:851-854.

The predictive power of baseline hemoglobin for transfusion risk in surgery patients

Preoperative hemoglobin concentration may be an important predictor of transfusion risk in surgical procedures with significant expected blood loss. Contemporary studies investigating transfusion risk with regard to the relationship between perioperative administration of Epoetin alfa and baseline hemoglobin provide data to test this hypothesis. The predictive power of seven preoperative variables (hemoglobin concentration, age, erythropoietin level, ferritin concentration, serum iron, total iron-binding capacity, and predicted blood volume) on transfusion risk was examined via retrospective logistic regression analysis of 276 orthopedic surgical patients. In the two studies used to perform the regression analysis, patients were treated daily with either Epoetin alfa or placebo. Based on the retrospective analyses, a prospective study was conducted to validate the hypothesis. Of the seven variables evaluated, baseline hemoglobin concentration and predicted blood volume were significantly predictive of transfusion risk in both Epoetin alfa- and placebo-treated patients. Further, an inverse correlation between hemoglobin concentration and transfusion risk was demonstrated in placebo-treated patients. Placebo-treated patients with hemoglobin > 10 to < or = 13 g/dL had an approximately twofold greater risk of transfusion than patients with hemoglobin > 13 g/dL. In contrast to placebo treatment, Epoetin alfa significantly reduced transfusion risk in patients with hemoglobin > 10 to < or = 13 g/dL. Baseline hemoglobin concentration is an excellent predictor of transfusion risk in orthopedic surgical patients. As a result, hemoglobin testing should be considered a part of routine preoperative testing for orthopedic surgical patients.

Anemia in the patient undergoing surgery and the transfusion decision. A review

The heightened awareness of the problems of transfusion reactions, disease transmission, and potential immunosuppression has led surgeons to reevaluate their reasons for transfusion. Current practice policies recommend that elective transfusion of allogeneic blood be avoided whenever possible in patients having surgery. If patients are to have appropriate transfusion, the basic pathophysiology and clinical response of the patient to anemia must be understood. This article reviews the physiologic response to anemia in the patient having surgery and explores the components of the decision to use transfusion.

Blood salvage after total hip arthroplasty

We performed a prospective, randomized study to determine the effect of postoperative collection and reinfusion of unwashed, filtered, salvaged blood on the transfusion requirements of 232 patients managed with a total hip replacement. Patients who were scheduled to have a primary or revision procedure were advised to predeposit two or four units of autologous blood, respectively, before the operation. In addition, intraoperative blood salvage was performed for all patients who had a revision procedure. The patients were randomly assigned to one of two groups: the first group was managed with postoperative blood salvage with use of the Autovac Postoperative Orthopaedic Autotransfusion Canister and the second, with closed suction drainage with use of the Hemovac system. In the first group, blood was collected from wound drains for four hours postoperatively; if at least 300 milliliters of blood was collected, the unwashed blood was reinfused through a microaggregate filter during a two-hour period. A maximum of 1000 milliliters of salvaged blood was reinfused; any blood that had not been reinfused within six hours after the beginning of collection was discarded. No complications or episodes of hypotension, confusion, cardiac or pulmonary compromise, febrile reaction, or coagulopathy were observed during or after the reinfusion of the unwashed, filtered, salvaged blood. No reinfusions were interrupted or discontinued. We found that postoperative reinfusion of unwashed, filtered, salvaged blood was associated with a decreased prevalence of homologous transfusion after a total hip replacement among patients for whom preoperatively donated autologous blood was not available.(ABSTRACT TRUNCATED AT 250 WORDS)

Preoperatively assessing and planning blood use for elective vascular surgery

Few guidelines exist for determining transfusion needs and strategies, namely, the appropriate use of autologous versus homologous blood for elective vascular surgery. To address this deficiency, we have developed and used an algorithm based on an analysis of the procedure, maximum surgical blood ordering schedule, patient status, and patient suitability for autologous alternatives. Data were derived from consecutive major vascular procedures done at our hospital from 1991 to 1992. The algorithm helps the surgeon assess transfusion need and patient suitability for autologous predonation and aids in selecting appropriate transfusion alternatives. Using this algorithm during the past year with 120 patients, we simplified transfusion decisions, reduced homologous blood use (to only 4.2%), and reduced wasting of autologous blood to less than 5% of the units predonated. We believe that the use of this algorithm will aid the vascular surgeon in choosing appropriate alternatives to allogeneic blood transfusion, thereby reducing the patient's exposure to risk. The algorithm should also reduce wasting of autologous blood.