Drugs to Minimize Perioperative Blood Loss in Cardiac Surgery

Blood conservation in cardiac surgery

Cardiac surgery is one of the largest users of blood and blood products--currently estimated at 15% of U.K. blood stocks. While the blood supply could be considered to be the safest it has ever been, there are well recognised risks associated with the transfusion of red cells and blood products. It is appropriate that attempts should be made to decrease and optimise the transfusion of blood and blood products.

Tranexamic acid is associated with less blood transfusion in off-pump coronary artery bypass graft surgery: a systematic review and meta-analysis

OBJECTIVE

Tranexamic acid reduces blood loss and transfusion in on-pump coronary artery bypass graft (CABG) surgery. Compared with on-pump, off-pump surgery is associated with less blood loss and transfusion. Therefore, tranexamic acid may be less effective for off-pump surgery, and its safety profile may be different in this setting. The aim of this study was to determine the efficacy and safety of tranexamic acid for off-pump CABG surgery.

DESIGN

Systematic review and meta-analysis.

SETTING

University of Edinburgh.

INTERVENTIONS

The administration of tranexamic acid.

METHODS

A systematic review of randomized controlled trials administering tranexamic acid to patients undergoing off-pump CABG surgery. A meta-analysis of 24-hour blood loss, postoperative allogeneic transfusion, and thromboembolic events.

MEASUREMENTS AND MAIN RESULTS

Eight trials were identified. The lack of appropriate data limited the meta-analysis on blood loss. Tranexamic acid significantly reduced the overall risk of allogeneic blood component transfusion (risk ratio = 0.47; 95% confidence intervals, 0.33-0.66; p < 0.0001) and packed red blood cell transfusions (risk ratio = 0.51; 95% CI, 0.36-0.71; p = 0.0001). No association was found between tranexamic acid and myocardial infarction, stroke, or pulmonary embolism. Population sizes of meta-analyses ranged from 466 to 544.

CONCLUSIONS

Tranexamic acid reduces blood transfusion after off-pump surgery. Although no association with adverse events was found, the population sample size was too small to detect rare but clinically significant adverse events. A well-designed randomized controlled trial with an appropriate sample size is required to confirm tranexamic acid effectiveness and safety in off-pump CABG surgery.

Interstitial plasmin activity with epsilon aminocaproic acid: temporal and regional heterogeneity

BACKGROUND

Epsilon aminocaproic acid (EACA) is used in cardiac surgery to modulate plasmin activity (PLact). The present study developed a fluorogenic-microdialysis system to measure in vivo region specific temporal changes in PLact after EACA administration.

METHODS

Pigs (25 to 35 kg) received EACA (75 mg/kg, n = 7) or saline in which microdialysis probes were placed in the liver, myocardium, kidney, and quadricep muscle. The microdialysate contained a plasmin-specific fluorogenic peptide and fluorescence emission, which directly reflected PLact, determined at baseline, 30, 60, 90, and 120 minutes after EACA/vehicle infusion.

RESULTS

Epsilon aminocaproic acid caused significant decreases in liver and quadricep PLact at 60, 90, 120 minutes, and at 30, 60, and 120 minutes, respectively (p < 0.05). In contrast, EACA induced significant biphasic changes in heart and kidney PLact profiles with initial increases followed by decreases at 90 and 120 minutes (p < 0.05). The peak EACA interstitial concentrations for all compartments occurred at 30 minutes after infusion, and were fivefold higher in the renal compartment and fourfold higher in the myocardium, when compared with the liver or muscle (p < 0.05).

CONCLUSIONS

Using a large animal model and in vivo microdialysis measurements of plasmin activity, the unique findings from this study were twofold. First, EACA induced temporally distinct plasmin activity profiles within the plasma and interstitial compartments. Second, EACA caused region-specific changes in plasmin activity profiles. These temporal and regional heterogeneic effects of EACA may have important therapeutic considerations when managing fibrinolysis in the perioperative period.

Cell salvage for minimising perioperative allogeneic blood transfusion

BACKGROUND

Concerns regarding the safety of transfused blood have prompted reconsideration of the use of allogeneic (from an unrelated donor) red blood cell (RBC) transfusion, and a range of techniques to minimise transfusion requirements.

OBJECTIVES

To examine the evidence for the efficacy of cell salvage in reducing allogeneic blood transfusion and the evidence for any effect on clinical outcomes.

SEARCH STRATEGY

We identified studies by searching CENTRAL (The Cochrane Library 2009, Issue 2), MEDLINE (1950 to June 2009), EMBASE (1980 to June 2009), the internet (to August 2009) and bibliographies of published articles.

SELECTION CRITERIA

Randomised controlled trials with a concurrent control group in which adult patients, scheduled for non-urgent surgery, were randomised to cell salvage (autotransfusion) or to a control group who did not receive the intervention.

DATA COLLECTION AND ANALYSIS

Data were independently extracted and the risk of bias assessed. Relative risks (RR) and weighted mean differences (WMD) with 95% confidence intervals (CIs) were calculated. Data were pooled using a random-effects model. The primary outcomes were the number of patients exposed to allogeneic red cell transfusion and the amount of blood transfused. Other clinical outcomes are detailed in the review.

MAIN RESULTS

A total of 75 trials were included. Overall, the use of cell salvage reduced the rate of exposure to allogeneic RBC transfusion by a relative 38% (RR 0.62; 95% CI 0.55 to 0.70). The absolute reduction in risk (ARR) of receiving an allogeneic RBC transfusion was 21% (95% CI 15% to 26%). In orthopaedic procedures the RR of exposure to RBC transfusion was 0.46 (95% CI 0.37 to 0.57) compared to 0.77 (95% CI 0.69 to 0.86) for cardiac procedures. The use of cell salvage resulted in an average saving of 0.68 units of allogeneic RBC per patient (WMD -0.68; 95% CI -0.88 to -0.49). Cell salvage did not appear to impact adversely on clinical outcomes.

AUTHORS' CONCLUSIONS

The results suggest cell salvage is efficacious in reducing the need for allogeneic red cell transfusion in adult elective cardiac and orthopaedic surgery. The use of cell salvage did not appear to impact adversely on clinical outcomes. However, the methodological quality of trials was poor. As the trials were unblinded and lacked adequate concealment of treatment allocation, transfusion practices may have been influenced by knowledge of the patients' treatment status potentially biasing the results in favour of cell salvage.

Temporally and regionally disparate differences in plasmin activity by tranexamic acid

BACKGROUND

A major complication associated with cardiac surgery is excessive and prolonged bleeding in the perioperative period. Improving coagulation by inhibiting fibrinolysis, primarily through inhibition of plasmin activity (PLact) with antifibrinolytics such as tranexamic acid (TXA), has been a pharmacological mainstay in cardiac surgical patients. Despite its almost ubiquitous use, the temporal and regional modulation of PLact profiles by TXA remains unexplored. Accordingly, we developed a fluorogenic-microdialysis system to measure in vivo dynamic changes in PLact after TXA administration in a large animal model.

METHODS

Pigs (25-35 kg) were randomly assigned to receive TXA (30 mg/kg, diluted into 50 mL normal saline; n = 9) or vehicle (50 mL normal saline; n = 7). Microdialysis probes were placed in the liver, myocardium, kidney, and quadriceps muscle compartments. The microdialysate infusion contained a validated plasmin-specific fluorogenic peptide. The fluorescence emission (standard fluorogenic units [SFU]) of the interstitial fluid collected from the microdialysis probes, which directly reflects PLact, was determined at steady-state baseline and 30, 60, 90, and 120 min after TXA/vehicle infusion. Plasma PLact was determined at the same time points using the same fluorogenic substrate approach.

RESULTS

TXA reduced plasma PLact at 30 min after infusion by >110 SFU compared with vehicle values (P < 0.05). Specifically, there was a decrease in liver PLact at 90 and 120 min after TXA infusion of >150 SFU (P < 0.05) and 175 SFU (P < 0.05), respectively. The decrease in liver PLact occurred 60 min after the maximal decrease in plasma PLact. In contrast, kidney, heart, and quadriceps PLact transiently increased followed by an overall decrease at 120 min.

CONCLUSIONS

Using a large animal model and in vivo microdialysis measurements of PLact, the unique findings from this study were 2-fold. First, TXA induced temporally distinct PLact profiles within the plasma and selected interstitial compartments. Second, TXA caused region-specific changes in PLact profiles. These temporal and regional differences in the effects of TXA may have important therapeutic considerations when managing fibrinolysis in the perioperative period.

Cell salvage for minimising perioperative allogeneic blood transfusion

BACKGROUND

Concerns regarding the safety of transfused blood, have prompted reconsideration of the use of allogeneic (blood from an unrelated donor) red blood cell (RBC) transfusion, and a range of techniques to minimise transfusion requirements.

OBJECTIVES

To examine the evidence for the efficacy of cell salvage in reducing allogeneic blood transfusion and the evidence for any effect on clinical outcomes.

SEARCH STRATEGY

We identified studies by searching CENTRAL (The Cochrane Library 2009, Issue 2), MEDLINE (1950 to June 2009), EMBASE (1980 to June 2009), the Internet (to August 2009) and bibliographies of published articles.

SELECTION CRITERIA

Randomised controlled trials with a concurrent control group in which adult patients, scheduled for non-urgent surgery, were randomised to cell salvage (autotransfusion), or to a control group, who did not receive the intervention.

DATA COLLECTION AND ANALYSIS

Data were independently extracted and the risk of bias assessed. Relative risks (RR) and weighted mean differences (WMD) with 95% confidence intervals (CIs) were calculated. Data were pooled using a random effects model. The primary outcomes were the number of patients exposed to allogeneic red cell transfusion, and the amount of blood transfused. Other clinical outcomes are detailed in the review.

MAIN RESULTS

A total of 75 trials were included. Overall, the use of cell salvage reduced the rate of exposure to allogeneic RBC transfusion by a relative 38% (RR=0.62: 95% CI 0.55 to 0.70). The absolute reduction in risk (ARR) of receiving an allogeneic RBC transfusion was 21% (95% CI 15% to 26%). In orthopaedic procedures the RR of exposure to RBC transfusion was 0.46 (95% CI 0.37 to 0.57) compared to 0.77 (95% CI 0.69 to 0.86) for cardiac procedures. The use of cell salvage resulted in an average saving of 0.68 units of allogeneic RBC per patient (WMD=-0.68; 95% CI -0.88 to -0.49). Cell salvage did not appear to impact adversely on clinical outcomes.

AUTHORS' CONCLUSIONS

The results suggest cell salvage is efficacious in reducing the need for allogeneic red cell transfusion in adult elective cardiac and orthopaedic surgery. The use of cell salvage did not appear to impact adversely on clinical outcomes. However, the methodological quality of trials was poor. As the trials were unblinded and lacked adequate concealment of treatment allocation, transfusion practices may have been influenced by knowledge of the patients' treatment status potentially biasing the results in favour of cell salvage.

Aprotinin use during cardiac surgery: recent alterations and effects on blood product utilization

OBJECTIVE

To investigate a single institution's changing use of aprotinin and subsequent effects on intraoperative blood product utilization (red blood cells/fresh frozen plasma) and postoperative clinical bleeding requiring reoperation.

DESIGN

Retrospective study.

SETTING

Single university institution (University of Chicago).

MEASUREMENTS

Data from 499 adult patients undergoing cardiac surgery requiring cardiopulmonary bypass (CPB) over a two-year period (February 2005 - January 2007) were reviewed. The first 12 months (Feb 2005 - Jan 2006, Group 2005-2006) of data were compared with that from the second 12-month period (Feb 2006 - Jan 2007, Group 2006-2007). Information regarding patient demographics, surgical procedures, aprotinin use (none, half-dose, full-dose), and blood product use during CPB was retrospectively retrieved and analyzed.

MAIN RESULTS

When Group 2006-2007 data was compared with that from Group 2005-2006, full-dose aprotinin use had significantly decreased (58% to 17%, P < 0.001), non-use of aprotinin significantly increased (18% to 47%, P < 0.001), while fresh frozen plasma (FFP) utilization during CPB significantly increased (24% to 36%, P = 0.004). Red blood cell (RBC) transfusion rates remained stable (67% - 69%) yet rates of RBC and FFP transfusion during CPB significantly increased (23% to 34%, P = 0.003). There was also a trend toward increased unplanned reoperations for excessive clinical bleeding (0 pts in Group 2005-2006, three pts in Group 2006-2007).

CONCLUSIONS

As the institution's use of high-dose aprotinin has significantly decreased, the number of patients requiring FFP and FFP/RBC combinations during CPB has significantly increased. Furthermore, a trend toward increasing incidence of unplanned reoperations for excessive clinical bleeding was noted.

Permissive hypotension and desmopressin enhance clot formation

BACKGROUND

Experimental studies of uncontrolled hemorrhage demonstrated that permissive hypotension (PH) reduces blood loss, but its effect on clot formation remains unexplored. Desmopressin (DDAVP) enhances platelet adhesion promoting stronger clots. We hypothesized PH and DDAVP have additive effects and reduce bleeding in uncontrolled hemorrhage.

METHODS

Rabbits (n = 42) randomized as follows: sham; normal blood pressure (NBP) resuscitation; PH resuscitation-60% baseline mean arterial pressure; NBP plus DDAVP 1 hour before (DDAVP NBP) or 15 minutes after beginning of shock (DDAVP T1 NBP); and PH plus DDAVP 1 hour before (DDAVP PH) or 15 minutes after beginning of shock (DDAVP T1 PH). Fluid resuscitation started 15 minutes after aortic injury and ended at 85 minutes. Intraabdominal blood loss was calculated, aortic clot sent for electron microscopy. Activated partial thromboplastin time, platelet count, thromboelastometry, arterial blood gases, and complete blood count were performed at baseline and 85 minutes. Analysis of variance was used for comparison.

RESULTS

NBP received more fluid volume and had greater intraabdominal blood loss. DDAVP, when administered preshock, significantly reduced blood loss in NBP and fluid requirement when given postshock. Platelets, arterial blood gas, complete blood count, and activated partial thromboplastin time were similar at 85 minutes. NBP delayed clot formation and worsened thrombodynamic potential on thromboelastometry, whereas PH and DDAVP improved. Electron microscopy showed lack of fibrin on NBP clots, whereas DDAVP and PH clots displayed exuberant fibrin/platelet aggregates. DDAVP NBP presented intermediate clots.

CONCLUSION

PH reduced bleeding and improved hemostasis compared with normotensive resuscitation. DDAVP given preshock exerted similar effects with normotensive resuscitation.

Perioperative blood conservation

This review examines the science and methodology of blood conservation in modern anaesthetic and surgical practice. Blood transfusion is associated with increased morbidity and mortality in all surgical patients, and the reduction or even elimination of transfusion has been and continues to be the subject of much research. Blood substitutes, despite extensive investigation, have not been proved successful in trials to date, and none have entered clinical practice. Pharmacological treatments include antifibrinolytic drugs (although aprotinin is no longer in clinical use), recombinant factor VIIa, desmopressin, erythropoietin and topical haemostatic agents, and the role of each of these is discussed. Autologous blood transfusion has recently fallen in popularity; however, cell salvage is almost ubiquitous in its use throughout Europe. Anaesthetic and surgical techniques may also be refined to improve blood conservation. Blood transfusion guidelines and protocols are strongly recommended, and repetitive audit and education are instrumental in reducing blood transfusion.

The effect of the suspension of the license for aprotinin on the care of patients undergoing cardiac surgery: a survey of cardiac anesthesiologists' and surgeons' opinions in the United Kingdom

OBJECTIVE

The primary aim was to poll the opinions of cardiac anesthesiologists and surgeons as to the effect of the suspension of the license for aprotinin on patients undergoing cardiac surgery.

DESIGN

A mailed questionnaire.

SETTING

United Kingdom.

PARTICIPANTS

Members of the Association of Cardiothoracic Anaesthetists and the Society for Cardiothoracic Surgery in Great Britain and Ireland with a UK address.

INTERVENTIONS

A structured questionnaire.

MEASUREMENTS AND MAIN RESULTS

Of the 546 dispatched surveys, 285 (52%) were returned. While the majority of respondents (61%) felt it had not had any effect, 29% of respondents felt the suspension of the license for aprotinin had had a detrimental effect on patient care and 2% an extremely detrimental effect. Eight percent of respondents reported a beneficial effect. Since license suspension, the reported use of aprotinin had declined and tranexamic acid use had risen. The majority of respondents reported no change in the use of packed red cells (66%), blood products (53%), mechanical cell salvage (84%), factor VIIa (79%), or frequency of reopening for bleeding (65%). Respectively, 32%, 45%, 24%, and 20% of respondents reported a perceived increased use of these products, and 30% reported an increased frequency of reopening for bleeding. Apart from knowledge regarding local aprotinin stock, there was no significant difference in opinions between surgeons and anesthesiologists.

CONCLUSIONS

While the majority of respondents felt that the suspension of the license for aprotinin had no effect, almost a third felt it had impacted negatively on the care of patients undergoing cardiac surgery.

A point-of-care assessment of the effects of desmopressin on impaired platelet function using multiple electrode whole-blood aggregometry in patients after cardiac surgery

BACKGROUND

Blood loss after cardiac surgery can be caused by acquired platelet dysfunction after cardiopulmonary bypass. Monitoring of platelet function is clinically important for the identification of patients experiencing such platelet dysfunction. 1-Deamino-8-D-arginine vasopressin (desmopressin acetate, DDAVP) has been shown to augment platelet function and to reduce blood loss in patients with platelet dysfunction. In this study, we examined the feasibility of whole blood multiple electrode aggregometry (MEA) for the detection of cardiopulmonary bypass-induced platelet dysfunction and investigated its ability to monitor DDAVP treatment.

METHODS

Fifty-eight consecutive patients with blood loss exceeding 150 mL/h in the first 2 consecutive hours after cardiac surgery were screened for suspected isolated platelet dysfunction. Twenty-two patients had suspected isolated platelet dysfunction and were enrolled in the study. Platelet dysfunction was assumed if conventional coagulation analyses (platelet count, activated partial thromboplastin time, international normalized ratio, and fibrinogen) did not show abnormal values as defined for transfusion of allogenic blood products, and no surgical cause of bleeding was suspected. Eleven patients received 0.3 microg/kg DDAVP, and 11 patients received no therapy in a nonrandomized manner. MEA was performed after stimulation with thrombin receptor-activating peptide (TRAPtest, 32 microM), adenosine diphosphate (ADPtest, 6.4 microM), and arachidonic acid (ASPItest, 0.5 mM) before and 2 hours after intervention. Conventional laboratory variables were recorded. The Mann-Whitney test was used to detect differences between the groups, and the Wilcoxon test was used to detect differences before and after intervention.

RESULTS

All enrolled patients showed platelet dysfunction that manifested as impaired platelet aggregation in MEA before intervention. After the intervention, platelet function improved in the DDAVP group (49 U [30/72 U], median [25th/75th percentile] postintervention vs 15 U [8/21 U] preintervention for the ASPItest [P < 0.001]; 35 U [24/54 U] vs 14 U [7/28 U] for the ADPtest [P = 0.002]; and 85 U [66/115 U] vs 64 U [26/88 U] for the TRAPtest [P = 0.007]). In contrast, MEA remained unchanged in the control group (22 U [10/50 U] postintervention vs 33 U [14/57 U] preintervention for the ASPItest [P = 0.175]; 17 U [12/20 U] vs 14 U [10/28 U] for the ADPtest [P = 0.147]; and 65 U [41/89 U] vs 57 U [30/91 U] for the TRAPtest [P = 0.123]).

CONCLUSIONS

Impaired platelet function after cardiac surgery can be assessed at the bedside using MEA. The effect of DDAVP on impaired platelet function can also be detected as significant improvement in platelet aggregation to all activators. This device might be helpful for the identification of patients who may benefit from DDAVP therapy.

Very long half-life plasminogen activator inhibitor type 1 reduces bleeding in a mouse model

OBJECTIVE

To investigate the potential for the future clinical use of a very long half-life plasminogen activator inhibitor type 1 (VLHL PAI-1) as a haemostatic agent.

MATERIALS AND METHODS

We developed a VLHL PAI-1 (half-life >700 h) recombinant mutant of PAI-1 and assessed VLHL PAI-1 for its ability to inhibit fibrinolysis in vitro using human, rabbit, mouse and rat blood. Fibrin clot lysis time, monitored by thromboelastometry, was determined at various concentrations of VLHL PAI-1. Also, we determined total bleeding time and total blood loss of control, VLHL PAI-1-, tissue-type plasminogen activator (tPA)- and tPA + VLHL PAI-1-treated mice.

RESULTS

Using a thromboelastometer, mouse blood was most similar to human blood in its coagulation and fibrinolytic characteristics. We evaluated the affect of VLHL PAI-1 on haemostasis using the mouse model and showed that VLHL PAI-1 is an effective inhibitor of fibrin clot degradation. It reduced time of bleeding and total blood loss.

CONCLUSION

VLHL PAI-1 may provide an important physiological mechanism to protect clots from premature dissolution in surgical and trauma settings.

Lessons learned in antifibrinolytic therapy: The BART trial

Despite nearly 2 decades of published reports and clinical trials demonstrating the relative safety and efficacy of aprotinin in adult cardiac surgical patients at increased risk of bleeding-culminating in an official endorsement of the usage of aprotinin in such patients from both cardiac surgery and anesthesiology subspecialty committees-several more recent studies have raised profound concerns regarding the safety of aprotinin in these same patients. These studies and the implications thereof have ultimately resulted in the withdrawal of aprotinin from clinical usage internationally. This article will briefly review these developments with the hope of understanding how this abrupt turnabout took place and will attempt to understand how such events can be avoided in the future.

Management of bleeding and of invasive procedures in patients with platelet disorders and/or thrombocytopenia: Guidelines of the Italian Society for Haemostasis and Thrombosis (SISET)

The optimal management of bleeding or its prophylaxis in patients with disorders of platelet count or function is controversial. The bleeding diathesis of these patients is usually mild to moderate: therefore, transfusion of platelet concentrates may be inappropriate, as potential adverse effects might outweigh its benefit. The availability of several anti-hemorrhagic drugs further compounds this problem, mainly because the efficacy/suitability of the various treatment options in different clinical manifestations is not well defined. In these guidelines, promoted by the Italian Society for Studies on Haemostasis and Thrombosis (Società Italiana per lo Studio dell'Emostasi e della Trombosi [SISET]), we aim at offering the best available evidence to help the physicians involved in the management of patients with disorders of platelet count or function. Literature review and appraisal of available evidence are discussed for different clinical settings and for different available treatments, including platelet concentrates (PC), recombinant activated factor VII, desmopressin, antifibrinolytics, aprotinin and local hemostatic agents.

Suction, salvage, sutures, and potions: blood management post-aprotinin

Hemostasis management of the cardiac surgical patient has changed following the withdrawal of aprotinin for use in cardiac surgical patients. The challenge to minimize blood loss and reduce exposure of cardiac surgical patients to blood products continues to grow with patients presenting being older and sicker and more complex procedures being performed. The cardiac surgery team has many options available for it to consider; although current recommendations strongly support the use of cell salvage as one process to assist in this challenge, other options need to be equally critically evaluated.

Preoperative evaluation of patients with liver cirrhosis undergoing open heart surgery

OBJECTIVE

Clinical outcomes after open heart surgery in patients with liver cirrhosis are not satisfactory. For evaluating hepatic function, the Child-Pugh classification has been widely used. It has been reported that open heart surgery can be performed safely in patients with mild liver cirrhosis. In this study, we examined the clinical outcomes after open heart surgery in patients with liver cirrhosis and evaluated the usefulness of the Child-Pugh classification.

METHODS

There were 12 liver cirrhosis patients who underwent open heart surgery between January 2002 and December 2006 at our institution. The severity of cirrhosis was graded according to the Child-Pugh classification. We reviewed clinical outcomes, such as postoperative mortality and morbidity, and tried to determine the risk factors. Finally, we assessed the usefulness of the Child-Pugh classification.

RESULTS

Six patients were classified as having Child class A, and the other six patients were classified as B. The overall mortality of group A was 50%, and that of group B was 17%. Postoperative major morbidities occurred in half of the patients of Child class A and in all of the patients of Child class B. Patients who experienced major morbidities had markedly lower levels of serum cholinesterase (106 +/- 46 vs. 199 +/- 72 IU/l; P = 0.02) and lower platelet level (7.5 +/- 2.9 vs. 11.9 +/- 3.6 x 104/microl; P = 0.04).

CONCLUSION

The mortality and morbidity rates were high even in the Child class A patients. The Child classification may be an insufficient method for evaluating hepatic function. We have to assess other factors, such as the serum cholinesterase level or the platelet count.

Tranexamic acid reduces blood loss in off-pump coronary artery bypass surgery

OBJECTIVE

This study was designed to evaluate the hemostatic effect of tranexamic acid in off-pump coronary artery bypass surgery.

DESIGN

A prospective, randomized, double-blind, placebo-controlled study.

SETTING

The Department of Anesthesiology and Cardiac Surgery, Medical Sciences University.

PARTICIPANTS

One hundred eight patients undergoing off-pump coronary artery bypass surgery were enrolled into the study. Eight patients were withdrawn, and 100 patients were divided into 2 groups.

INTERVENTIONS

Fifty patients received tranexamic acid (bolus 1 g before skin incision and followed by maintenance dose of 400 mg/h during surgery), and 50 patients received saline.

MEASUREMENT AND MAIN RESULTS

Hematologic parameters, volume of blood loss, blood transfusion, and other clinical data were recorded throughout the perioperative period. Twenty-four-hour postoperative blood loss was significantly less in the tranexamic acid group compared with the control group (471 +/- 182 v 844 +/- 303). Patients in the tranexamic acid group received significantly less allogeneic blood (8 v 31 units).

CONCLUSION

Bleeding and hemorrhagic complications and the consequent need for allogeneic transfusion are still major problems after off-pump coronary artery bypass surgery. Tranexamic acid appears to be effective in reducing postoperative bleeding and the need for allogeneic blood products.

Aprotinin in primary cardiac surgery: operative outcome of propensity score-matched study

BACKGROUND

Some recent multicenter series have questioned the safety of aprotinin in primary cardiac operations. We report a large, single-center experience with aprotinin therapy in primary cardiac operations and discuss the limitations and potential confounders of current treatment strategies.

METHODS

We compared myocardial infarction, neurologic events, renal insufficiency, and operative death after first-time coronary or valve procedures, or both, in 3334 patients treated with full-dose aprotinin with 3417 patients not treated with aprotinin who underwent operation between March 1998 and January 2007. Further analysis was performed for 341 propensity score-matched pairs.

RESULTS

There were substantial differences between the groups. Aprotinin patients were higher risk on account of older age, unstable symptoms, poor ejection fraction, preoperative hemodynamic support, emergency/urgent operations, and combined coronary/valve operations. Postoperative bleeding and blood product transfusion were considerably reduced in aprotinin patients, as was median duration of mechanical ventilation. Aprotinin was neither a predictor of postoperative myocardial infarction, renal insufficiency, neurologic dysfunction, or operative death. Achieving parity between the groups by propensity score matching eliminated the elevated rates of postoperative renal insufficiency, neurologic dysfunction, and operative death observed in aprotinin patients in the unmatched comparison. These adverse outcomes were evenly distributed between matched groups. Conversely, blood transfusion had univariate associations with all adverse outcome measures.

CONCLUSIONS

Full-dose aprotinin use was not associated with myocardial infarction, neurologic dysfunction, renal insufficiency, or death after coronary or valve operations. We observed less postoperative bleeding and blood product transfusion, and early extubation with the use of aprotinin.

The role of Amicar in same-day anterior and posterior spinal fusion for idiopathic scoliosis

STUDY DESIGN

A retrospective study of the effectiveness of Amicar (epsilon aminocaproic acid).

OBJECTIVE

Evaluate the effectiveness of Amicar in decreasing perioperative blood loss and transfusion requirements in same-day anterior (ASF) and posterior spinal fusion (PSF) with segmental spinal instrumentation (SSI) for idiopathic scoliosis.

SUMMARY OF BACKGROUND DATA

Preliminary prospective, prospective randomized double-blind, and fibrinogen studies have demonstrated Amicar to be effective in decreasing perioperative blood loss in patients with idiopathic scoliosis undergoing PSF with SSI. Increased fibrinogen secretion is a possible explanation.

METHODS

There were 73 consecutive patients divided into 3 study groups based on the administration of Amicar: Group 1 (n = 16), no Amicar; Group 2 (n = 18), Amicar for the PSF with SSI only; and Group 3 (n = 39), Amicar for both ASF and PSF with SSI. All patients were managed using the same general anesthesia technique, intraoperative procedure, postoperative care path, and indications for transfusion (hemoglobin <7 g/dL). Total perioperative blood loss (estimated intraoperative blood loss for both procedures and measured postoperative chest tube and PSF wound suction drainage) and total transfusion requirements between groups were compared using one-way ANOVA.

RESULTS

There were statistically significant decreases in mean estimated intraoperative PSF with SSI, total perioperative blood loss, and transfusion requirements in the 2 Amicar groups. However, Amicar had no significant effect on estimated intraoperative ASF blood loss, chest tube drainage, or PSF wound suction drainage. Total perioperative blood loss and transfusion requirements (cell saver, autologous, directed, and allogeneic blood) were: 3442.8 +/- 1344.0 mL and 1537.1 +/- 905.1 mL in Group 1; 2089.8 +/- 684.0 mL and 485.2 +/- 349.8 mL in Group 2; and 2184.1 +/- 1163.7 mL and 531.5 +/- 510.5 mL in Group 3. There were no Amicar related complications.

CONCLUSION

Amicar was highly effective in decreasing total perioperative blood loss and transfusion requirements in same-day ASF and PSF with SSI for idiopathic scoliosis. It results in less preoperative autologous blood donation, perioperative blood transfusion, costs, and potential transfusion-related complications. It was most effective in decreasing intraoperative estimated PSF with SSI blood loss. It had no significant effect during the ASF, postoperative chest tube, or PSF wound suction drainage. We now recommend that it be used for the PSF with SSI procedure only.

A benefit-risk review of systemic haemostatic agents: part 1: in major surgery

Systemic haemostatic agents play an important role in the management of blood loss during major surgery where significant blood loss is likely and their use has increased in recent times as a consequence of demand for blood products outstripping supply and the risks associated with transfusions. Their main application is as prophylaxis to reduce bleeding in major surgery, including cardiac and orthopaedic surgery and orthotopic liver transplantation. Aprotinin has been the predominant agent used in this setting; of the other antifibrinolytic agents that have been studied, tranexamic acid is the most effective and epsilon-aminocaproic acid may also have a role. Eptacog alfa (recombinant factor VIIa) has also shown promise. Tranexamic acid, epsilon-aminocaproic acid and eptacog alfa are generally well tolerated; however, when considering the methods to reduce or prevent blood loss intra- and postoperatively, the benefits of these agents need to be weighed against the risk of adverse events. Recently, concerns have been raised about the safety of aprotinin after an association between increased renal dysfunction and mortality was shown in retrospective observational studies and an increase in all-cause mortality with aprotinin relative to tranexamic acid or epsilon-aminocaproic acid was seen after a pre-planned periodic analysis of the large BART (Blood conservation using Antifibrinolytics in a Randomized Trial) study. The latter finding resulted in the trial being halted, and aprotinin has subsequently been withdrawn from the market pending detailed analysis of efficacy and safety results from the study. Part 1 of this benefit-risk review examines the efficacy and adverse effect profiles of systemic haemostatic agents commonly used in surgery, and provides individual benefit-risk profiles that may assist clinicians in selecting appropriate pharmacological therapy in this setting.

[The decrease of preoperative autologous transfusion in France has not been linked to an increase of homologous red cell concentrates]

OBJECTIVE

The use of preoperative autologous blood transfusion has dramatically decreased in France. The aim of this study was to evaluate the evolution of practice both of autologous and homologous Red Blood Cells (RBC) concentrates transfusion between 2002 and 2005, and to asses the consequences of the highlighted changes.

MATERIAL AND METHODS

Data on blood transfusion are collected and validated nationwide by a network of regional coordinators of haemovigilance. For each hospital, from 2002 to 2005, the annual changes in the number of transfused homologous and autologous RBC have been evaluated. The ratio of preoperative autologous RBC, number of autologous RBC divided by the number of all RBC, has also been calculated. Hospitals have been split into three cohorts, according to their 2005 autologous RBC ratio. For each cohort, correlations between the variations of the number of autologous, homologous and total RBC in each hospital have been studied.

RESULTS

Data have been validated for 22 French regions that performed 71.8% of the total French transfusion in 2004. In 2005, 1,831,544 labile blood products have been transfused in 1197 hospitals and clinics among which 379 have used preoperative autologous transfusion. A total of 37,289 autologous RBC have been transfused in 2003, 28,689 in 2004 (-23.1%) and 17,758 in 2005 (-38.1%). The first cohort of 269 hospitals had a ratio of autologous RBC under 3%, the second cohort of 38 hospitals, a ratio between 3 and 6%, while the third cohort of 72 hospitals had transfused 6% or more of autologous RBC. In the two first cohorts, non-surgical activities were so large that it was impossible to assess the changes in surgical use of transfusion. The third cohort, with a ratio of 6% or more, was essentially devoted to surgery (88% of beds). These hospitals and clinics have transfused 13,076 autologous RBC in 2002 and 8583 in 2005 (-34.4%). In this group, there was a statistical correlation between the decrease of autologous RBC and the decrease of total RBC (r(2)=0.36), and no increase in the transfusion of homologous RBC has been observed. During the same period, neither hospitals nor clinics showed any decrease of their surgical activity. The drop of autologous RBC transfusion led to a decrease of the total number of RBC transfused and thus, to a decrease of the global exposure to transfusion hazard.

CONCLUSION

The present results confirmed a decline of preoperative autologous transfusion in France, between 2002 and 2005. Meanwhile no supplementary need of homologous RBC has been observed among hospitals, performing surgery that formerly had a high ratio of autologous RBC.

Tranexamic acid and primary coronary artery bypass surgery: a prospective study

Tranexamic acid was used to reduce postoperative drainage and allogenic blood transfusion requirements in patients undergoing on-pump primary coronary bypass surgery. Over 12 months, 222 patients participated in this prospective, randomized, placebo-controlled, double-blind study conducted at a tertiary center. Half of the patients were randomly allocated to receive tranexamic acid as a bolus (10 mg x kg(-1)) prior to sternotomy, followed by an infusion (1 mg x kg(-1) x hr(-1)) up to the time of starting of protamine. The other 111 patients received a saline bolus and infusion. Postoperative drainage and transfusion requirements were measured in all patients. Markers of graft patency, hemostasis, hemodynamic stability, and fibrinolysis were evaluated. Chest closure time, renal function parameters, allergic reactions, incidence of stroke, re-exploration, and hospital mortality were also noted. Postoperative drainage was significantly less and blood conservation considerably better when tranexamic acid was used. Post-bypass hemostasis was achieved faster, fibrinolysis was less, and there was no evidence of increased incidence of graft occlusion in the group given tranexamic acid.

[Changes in transfusion practice for surgery]

The context of transfusion has changed in recent years. Some data could lead to an increased demand: the risk of viral transmission has significantly decreased; a national survey has revealed that the mortality related to an insufficient or delayed transfusion was higher to the side effects of the transfusion itself. Some other data could decrease the demand: the preoperative use of EPO is now easier; the intraoperative use of antifibrinolytic has been shown to be efficient. The number of allogenic red blood cells units (RBCs) transfused each year in France regularly increases, while the transfusion of predeposited autologous blood is in sharp decline. However, in hospitals still using but reducing this technique, the consumption of allogenic RBCs does not increase and the transfusion of any blood (allogenic and/or autologous) decreases. The strategy is based on preoperative evaluation of usual blood loss and tolerable blood loss by accepting a reasonable risk of allogenic blood transfusion. Advances in public health seem to be found above all in the analysis of system failures.

Anti-fibrinolytic use for minimising perioperative allogeneic blood transfusion

BACKGROUND

Concerns regarding the safety of transfused blood have led to the development of a range of interventions to minimise blood loss during major surgery. Anti-fibrinolytic drugs are widely used, particularly in cardiac surgery and previous reviews have found them to be effective in reducing blood loss and the need for transfusion. Recently, questions have been raised regarding the comparative performance of the drugs and the safety of the most popular agent, aprotinin.

OBJECTIVES

To assess the comparative effects of the anti-fibrinolytic drugs aprotinin, tranexamic acid (TXA), and epsilon aminocaproic acid (EACA) on blood loss during surgery, the need for red blood (RBC) transfusion, and adverse events, particularly vascular occlusion, renal dysfunction, and death.

SEARCH STRATEGY

We searched CENTRAL, MEDLINE, EMBASE, and the internet. References in identified trials and review articles were checked and trial authors were contacted to identify any additional studies. The searches were last updated in July 2006.

SELECTION CRITERIA

Randomised controlled trials (RCTs) of anti-fibrinolytic drugs in adults scheduled for non-urgent surgery. Eligible trials compared anti-fibrinolytic drugs with placebo (or no treatment), or with each other.

DATA COLLECTION AND ANALYSIS

Two authors independently assessed trial quality and extracted data.

MAIN RESULTS

This review summarises data from 211 RCTs that recruited 20,781 participants. Data from placebo/inactive controlled trials, and from head-to-head trials suggest an advantage of aprotinin over the lysine analogues TXA and EACA in terms of operative blood loss, but the differences were small. Aprotinin reduced the probability of requiring RBC transfusion by a relative 34% (relative risk [RR] 0.66, 95% confidence interval [CI] 0.61 to 0.71). The RR for RBC transfusion with TXA was 0.61 (95% CI 0.54 to 0.69) and it was 0.75 (95% CI 0.58 to 0.96) with EACA. When the pooled estimates from the head-to-head trials of the two lysine analogues were combined and compared to aprotinin alone, aprotinin appeared superior in reducing the need for RBC transfusion: RR 0.83 (95% CI 0.69 to 0.99). Aprotinin reduced the need for re-operation due to bleeding: RR 0.48 (95% CI 0.35 to 0.68). This translates into an absolute risk reduction of just under 3% and a number needed-to-treat (NNT) of 37 (95% CI 27 to 56). Similar trends were seen with TXA and EACA, but the data were sparse and the differences failed to reach statistical significance. The blood transfusion data were heterogeneous and funnel plots indicate that trials of aprotinin and the lysine analogues may be subject to publication bias. Evidence of publication bias was not observed in trials reporting re-operation rates. Adjustment for these effects reduced the magnitude of estimated benefits but did not negate treatment effects. However, the apparent advantage of aprotinin over the lysine analogues was small and may be explained by publication bias and non-equivalent drug doses. Aprotinin did not increase the risk of myocardial infarction (RR 0.92, 95% CI 0.72 to 1.18), stroke (RR 0.76, 95% CI 0.35 to 1.64) renal dysfunction (RR 1.16, 95% CI 0.79 to 1.70) or overall mortality (RR 0.90, 95% CI 0.67 to 1.20). The analyses of myocardial infarction and death included data from the majority of subjects recruited into the clinical trials of aprotinin. However, under-reporting of renal events could explain the lack of effect seen with aprotinin. Similar trends were seen with the lysine analogues but data were sparse. These results conflict with the results of recently published non-randomised studies.

AUTHORS' CONCLUSIONS

Anti-fibrinolytic drugs provide worthwhile reductions in blood loss and the need for allogeneic red cell transfusion. Based on the results of randomised trials their efficacy does not appear to be offset by serious adverse effects. In most circumstances the lysine analogues are probably as effective as aprotinin and are cheaper; the evidence is stronger for tranexamic acid than for aminocaproic acid. In high risk cardiac surgery, where there is a substantial probability of serious blood loss, aprotinin may be preferred over tranexamic acid. Aprotinin does not appear to be associated with an increased risk of vascular occlusion and death, but the data do not exclude an increased risk of renal failure. There is no need for further placebo-controlled trials of aprotinin or lysine analogues in cardiac surgery. The principal need is for large comparative trials to assess the relative efficacy, safety and cost-effectiveness of anti-fibrinolytic drugs in different surgical procedures.

Aprotinin in Cardiac Surgery: A Review of Conventional and Novel Mechanisms of Action

Induction of the coagulation and inflammatory cascades can cause multiorgan dysfunction after cardiopulmonary bypass (CPB). In light of these observations, strategies that can stabilize the coagulation process as well as attenuate the inflammatory response during and after cardiac surgery are important. Aprotinin has effects on hemostasis. In addition, aprotinin may exert multiple biologically relevant effects in the context of cardiac surgery and CPB. For example, it decreases neutrophil and macrophage activation and chemotaxis, attenuates release and activation of proinflammatory cytokines, and reduces oxidative stress. Despite these perceived benefits, the routine use of aprotinin in cardiac surgery with CPB has been called into question. In this review, we examined this controversial drug by discussing the classical and novel pathways in which aprotinin may be operative in the context of cardiac surgery.

The use of desmopressin as a hemostatic agent: a concise review

Desmopressin, a synthetic derivative of the antidiuretic hormone vasopressin, is the treatment of choice for most patients with von Willebrand disease and mild hemophilia A. Moreover, the compound has been shown to be useful in a variety of inherited and acquired hemorrhagic conditions, including some congenital platelet function defects, chronic liver disease, uremia, and hemostatic defects induced by the therapeutic use of antithrombotic drugs such as aspirin and ticlopidine. Finally, desmopressin has been used as a blood saving agent in patients undergoing operations characterized by large blood loss and transfusion requirements, but studies suggest that this is not as effective as other methods. This review briefly summarizes the current clinical indications on the use of desmopressin as a hemostatic agent.

Perioperative blood transfusion and blood conservation in cardiac surgery: the Society of Thoracic Surgeons and The Society of Cardiovascular Anesthesiologists clinical practice guideline

BACKGROUND

A minority of patients having cardiac procedures (15% to 20%) consume more than 80% of the blood products transfused at operation. Blood must be viewed as a scarce resource that carries risks and benefits. A careful review of available evidence can provide guidelines to allocate this valuable resource and improve patient outcomes.

METHODS

We reviewed all available published evidence related to blood conservation during cardiac operations, including randomized controlled trials, published observational information, and case reports. Conventional methods identified the level of evidence available for each of the blood conservation interventions. After considering the level of evidence, recommendations were made regarding each intervention using the American Heart Association/American College of Cardiology classification scheme.

RESULTS

Review of published reports identified a high-risk profile associated with increased postoperative blood transfusion. Six variables stand out as important indicators of risk: (1) advanced age, (2) low preoperative red blood cell volume (preoperative anemia or small body size), (3) preoperative antiplatelet or antithrombotic drugs, (4) reoperative or complex procedures, (5) emergency operations, and (6) noncardiac patient comorbidities. Careful review revealed preoperative and perioperative interventions that are likely to reduce bleeding and postoperative blood transfusion. Preoperative interventions that are likely to reduce blood transfusion include identification of high-risk patients who should receive all available preoperative and perioperative blood conservation interventions and limitation of antithrombotic drugs. Perioperative blood conservation interventions include use of antifibrinolytic drugs, selective use of off-pump coronary artery bypass graft surgery, routine use of a cell-saving device, and implementation of appropriate transfusion indications. An important intervention is application of a multimodality blood conservation program that is institution based, accepted by all health care providers, and that involves well thought out transfusion algorithms to guide transfusion decisions.

CONCLUSIONS

Based on available evidence, institution-specific protocols should screen for high-risk patients, as blood conservation interventions are likely to be most productive for this high-risk subset. Available evidence-based blood conservation techniques include (1) drugs that increase preoperative blood volume (eg, erythropoietin) or decrease postoperative bleeding (eg, antifibrinolytics), (2) devices that conserve blood (eg, intraoperative blood salvage and blood sparing interventions), (3) interventions that protect the patient's own blood from the stress of operation (eg, autologous predonation and normovolemic hemodilution), (4) consensus, institution-specific blood transfusion algorithms supplemented with point-of-care testing, and most importantly, (5) a multimodality approach to blood conservation combining all of the above.

Fibrinogen levels following Amicar in surgery for idiopathic scoliosis

STUDY DESIGN

Prospective evaluation of fibrinogen levels before surgery and after surgery in patients with idiopathic scoliosis undergoing posterior spinal fusion (PSF) and segmental spinal instrumentation (SSI) who received Amicar to decrease perioperative blood loss.

OBJECTIVES

To assess a possible association between postoperative fibrinogen levels and Amicar administration.

SUMMARY OF BACKGROUND DATA

Our previous randomized, double-blind (Amicar and control) study demonstrated a rise in fibrinogen levels on the first postoperative day in the Amicar group, but not in the control group. Fibrinogen levels were not measured on the remaining postoperative days. We subsequently measured fibrinogen levels on all postoperative days in 21 consecutive patients with idiopathic scoliosis and found a dramatic increase throughout the postoperative hospitalization. This study is a continuation of our analysis of postoperative fibrinogen levels.

METHODS

We analyzed fibrinogen levels before surgery and on all postoperative days (4 or 5 days) until discharge in 51 consecutive patients, including our 21 previously reported patients, who received Amicar and underwent a PSF and SSI. We also analyzed the same factors with respect to perioperative blood loss as in our previous Amicar studies.

RESULTS

There were 41 females and 10 males with a mean age at surgery of 14.2 +/- 1.8 years. Their mean hospitalization was 4.6 +/- 0.8 days. Their mean estimated intraoperative blood loss was 766 +/- 308 mL and postoperative suction drainage 532 +/- 186 mL for a total perioperative blood loss of 1297 +/- 311 mL. The perioperative transfusion requirements were 0.5 +/- 0.6 U per patient. The preoperative fibrinogen was 255.5 +/- 58.3 mg/dL, and it rose steadily throughout the postoperative period to 680.9 +/- 111.9 mg/dL on the fifth postoperative day. There were no complications related to the use of Amicar.

CONCLUSIONS

Fibrinogen levels rise steadily throughout the postoperative period. The significance of this increase is unknown. Was it due to the use of Amicar or just the effects of surgery itself? Further investigations will be necessary.

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.

Full-dose aprotinin use in coronary artery bypass graft surgery: an analysis of perioperative pharmacotherapy and patient outcomes

BACKGROUND

Inappropriate activation of hemostasis and inflammation may contribute to postoperative morbidity and mortality. The serine protease inhibitor, aprotinin, has been shown to prevent tissue and organ injury in laboratory and animal studies. In this retrospective analysis, we evaluated the relationship of aprotinin therapy with organ dysfunction in humans undergoing coronary artery bypass graft surgery (CABG).

METHODS

Data from prospective randomized, double-blind, placebo-controlled studies evaluating the safety and efficacy of full-dose aprotinin (2 million KIU load, 2 million KIU pump prime, and 0.5 million KIU/h continuous infusion) to reduce blood loss and transfusion requirements in patients undergoing CABG (placebo, n = 861; aprotinin, n = 862) were examined retrospectively. Primary end-points were death, adverse cerebrovascular outcome, myocardial infarction (MI), and pharmacological interventions (inotropic drugs, vasopressors, and antiarrhythmics).

RESULTS

Univariate analysis showed that relative to placebo, full-dose aprotinin therapy was associated with significant effects on the incidence of adverse cerebrovascular outcome (odds ratio [OR] 0.42, 95% confidence interval [CI] 0.19-0.93; P = 0.03) and use of inotropic drugs (OR 0.79, 95% CI 0.65-0.97; P = 0.02), vasopressors (OR 0.74, 95% CI 0.61-0.90; P < 0.01), and antiarrhythmics (OR 0.79, 95% CI 0.65-0.96; P = 0.02), but not death (OR = 1.00, 95% CI 0.54-1.85; P = 1.0) or MI (OR 0.92, 95% CI 0.64-1.31; P = 0.6). Multivariate analysis confirmed results of univariate analysis.

CONCLUSIONS

This retrospective analysis of data collected from prospective, randomized, placebo-controlled studies in CABG shows that full-dose aprotinin use was associated with a lower risk of adverse cerebrovascular outcomes and a reduced need for use of vasoactive drugs; the risk of death and perioperative MI was not affected by aprotinin therapy.

Cell salvage for minimising perioperative allogeneic blood transfusion

BACKGROUND

Concerns regarding the safety of transfused blood, have prompted reconsideration of the use of allogeneic (blood from an unrelated donor) red blood cell (RBC) transfusion, and a range of techniques to minimise transfusion requirements.

OBJECTIVES

To examine the evidence for the efficacy of cell salvage in reducing allogeneic blood transfusion and the evidence for any effect on clinical outcomes.

SEARCH STRATEGY

We searched the Cochrane Central Register of Controlled Trials, MEDLINE, EMBASE, Current Contents and the websites of international health technology assessment agencies. The reference lists in identified trials and review articles were also searched, and study authors were contacted to identify additional studies. The searches were updated in January 2004.

SELECTION CRITERIA

Controlled parallel group trials in which adult patients, scheduled for non-urgent surgery, were randomised to cell salvage, or to a control group, who did not receive the intervention.

DATA COLLECTION AND ANALYSIS

Two authors independently screened search results, extracted data and assessed methodological quality. The main outcomes measures were the number of patients exposed to allogeneic red cell transfusion, and the amount of blood transfused. Other outcomes measured were re-operation for bleeding, blood loss, post-operative complications (thrombosis, infection, non-fatal myocardial infarction, renal failure), mortality, and length of hospital stay (LOS).

MAIN RESULTS

Overall, the use of cell salvage reduced the rate of exposure to allogeneic RBC transfusion by a relative 39% (relative risk [RR] = 0.61: 95% confidence interval [CI] 0.52 to 0.71). The absolute reduction in risk (ARR) of receiving an allogeneic RBC transfusion was 23% (95% CI 16% to 30%). In orthopaedic procedures the RR of exposure to RBC transfusion was 0.42 (95% CI 0.32 to 0.54) compared to 0.77 (95% CI 0.68 to 0.87) for cardiac procedures. The use of cell salvage resulted in an average saving of 0.67 units of allogeneic RBC per patient (weighted mean difference was -0.64; 95% CI -0.89 to -0.45). Cell salvage did not appear to impact adversely on clinical outcomes.

AUTHORS' CONCLUSIONS

The results suggest cell salvage is efficacious in reducing the need for allogeneic red cell transfusion in adult elective surgery. However, the methodological quality of trials was poor. As the trials were unblinded and lacked adequate concealment of treatment allocation, transfusion practices may have been influenced by knowledge of the patients' treatment status biasing the results in favour of cell salvage.

Pharmacological approaches to reducing blood loss and transfusions in the surgical patient

PURPOSE

To review the efficacy, effectiveness and safety of hemostatic drugs to reduce surgical blood loss.

METHODS

Analysis of randomized controlled trials and meta-analyses exploring the efficacy of desmopressin, aprotinin, lysine analogues and recombinant activated factor VII (rFVIIa) on clinically important endpoints.

MAIN FINDINGS

Although potentially useful in surgical patients with mild hemophilia or type I von Willebrand's disease, desmopressin has no proven benefit in patients without previous hemostatic defects. Aprotinin has been studied extensively in cardiopulmonary bypass surgery, with evidence of a blood sparing effect. Additional benefits are suggested. The drug is less consistently effective in liver transplantation and major orthopedic surgery. Although rare, hypersensitivity reactions to aprotinin may occur, especially on re-exposure. Tranexamic acid can reduce blood transfusion in cardiac surgery, liver transplantation and total knee arthroplasty surgery with a satisfactory safety profile. Epsilon aminocaproic acid has not been investigated adequately, despite its widespread use. While rFVIIa may be beneficial in controlling massive coagulopathic bleeding in trauma and surgical patients, there is currently no evidence to support its prophylactic use in elective surgical patients.

CONCLUSION

Aprotinin and tranexamic acid are valuable pharmacologic options for reducing surgical bleeding. The expected benefit of these drugs is highly dependent on the actual blood usage for a given procedure at the institutional level. More studies using clinically significant endpoints are necessary to assess the relative efficacy and optimal dosing of these drugs.

Increased Fibrinolysis and Platelet Activation in Elderly Patients Undergoing Coronary Bypass Surgery

Reexploration for hemorrhage after cardiac surgery is associated with increased morbidity and mortality. Elderly cardiac surgical patients have an increased risk of excessive bleeding and reexploration. In the present study we investigated the perioperative hemostatic function in elderly patients compared with younger patients undergoing coronary artery bypass grafting. Twenty-five elderly (75 yr and older) and 25 younger (younger than 60 yr) patients were included in the study. Blood samples for the analysis of platelet counts, international normalized ratio, activated partial thromboplastin time, fibrinogen, d-dimer, antithrombin, prothrombin fragment 1 + 2, thrombin-antithrombin complex, plasmin inhibitor, neutrophil-activating peptide 2, and platelet-monocyte complexes were drawn preoperatively, 30 min, and 3 h postoperatively and approximately 20 h postoperatively. Elderly patients had an increased activation of the hemostatic system. In particular, elderly patients showed a more pronounced increase in fibrinolysis and platelet activation postoperatively compared with younger patients.

Cost and utilization of blood transfusion associated with spinal surgeries in the United States

The purpose of this study was to examine factors associated with the utilization and cost of blood transfusion during and post-spinal fusion surgery. A retrospective, observational study of 42,029 inpatients undergoing spinal fusion surgery in United States hospitals participating in the Perspective( Comparative Database for inpatient use was conducted. Descriptive analysis, logistic regression, and ordinary least squares (OLS) regression were used to describe the factors associated with the use and cost of allogeneic blood transfusion (ABT). Hospitalization costs were $18,690 (SD=14,159) per patient, erythropoietin costs were $85.25 (SD=3,691.66) per patient, and topical sealant costs were $414.34 (SD=1,020.06) per patient. Sub-analysis of ABT restricted to users revealed ABT costs ranged from $312.24 (SD=543.35) per patient with whole blood to $2,520 (SD=3,033.49) per patient with fresh frozen plasma. Patients that received hypotensive anesthesia (OR,1.61; 95% CI, 1.47-1.77), a volume expander (OR,1.95; 95% CI, 1.75-2.18), autologous blood (OR, 2.04; 95% CI, 1.71-2.42), or an erythropoietic agent (OR=1.64; 95% CI, 1.27-2.12) had a higher risk of ABT. Patients that received cell salvage had a lower risk of transfusion (OR=0.40; 95% CI, 0.32-0.50). Most blood avoidance techniques have low utilization or do not reduce the burden of transfusion associated with spinal fusion.

Practical management of anticoagulation, bleeding and blood product support for cardiac surgery. Part one: bleeding and anticoagulation issues

There are many challenging problems related to bleeding and anticoagulation in cardiac surgery. Practical guidelines, which are based on available evidence, can help to direct management issues of post-bypass bleeding, perioperative anticoagulation and the use of haemostatic agents. The patient's bleeding history is the most useful preoperative screening test of haemostasis. The input of a haematologist is often valuable in a number of areas, such as preoperative assessment of patients with a significant history of bleeding, or past history of heparin-induced thrombocytopenia, a lupus anticoagulant, or recent venous thromboembolism. Cardiothoracic surgeons, anaesthetists, perfusionists and haematologists can ensure 'best practice' by being actively involved in the development of 'local' transfusion and anticoagulation guidelines, hospital transfusion committee policies, and audits.

Resource utilization and costs of blood management services associated with knee and hip surgeries in US hospitals

This article assesses the use and costs of blood transfusion during knee and hip surgery through a retrospective observational study of 92,223 discharged inpatients who had undergone knee or hip surgery from July 1, 2003, through June 30, 2004; a sample of US hospitals that participated in the Perspective Comparative Database (Premier Inc., Charlotte, NC) was used. Descriptive and multivariate analyses were performed to determine the use and costs of allogeneic blood transfusion (ABT). The average cost of ABT per user ranged from $387 (SD=$952) for red blood cells to $6585 (SD=$11,162) for cryoprecipitate. Utilization rates in the sample were as follows: antifibrinolytics, 0.14%; topical sealants, 3.24%; volume expanders, 3.89%; erythropoietin agents, 5.08%; and hypotensive anesthesia, 22.28%. Patients who were given volume expanders ($133.73, SD=$23.00, P<.01) or erythropoietin ($177.72, SD=$34.61, P<.01) had higher costs associated with ABT than did those who did not use volume expanders or erythropoietin. Patients who received hypotensive anesthesia (odds ratio [OR]=1.96; 95% confidence interval [CI], 1.87-2.06), a volume expander (OR=1.71; 95% CI, 1.57- 1.85), a topical sealant (OR=1.61; 95% CI, 1.45-1.79), or an erythropoietic agent (OR=2.30; 95% CI, 2.06-2.57) had a greater likelihood of ABT. Investigators concluded that most transfusion reduction techniques are underused, or they do not reduce the burden of ABT associated with knee or hip surgery.

A randomized, double-blind, and placebo-controlled study with tranexamic acid of bleeding and fibrinolytic activity after primary coronary artery bypass grafting

Cardiopulmonary bypass is frequently associated with excessive blood loss. Platelet dysfunction is the main cause of non-surgical bleeding after open-heart surgery. We randomized 65 patients in a double-blind fashion to receive tranexamic acid or placebo in order to determine whether antifibrinolytic therapy reduces chest tube drainage. The tranexamic acid group received an intravenous loading dose of 10 mg/kg, before the skin incision, followed by a continuous infusion of 1 mg kg(-1) h(-1) for 5 h. The placebo group received a bolus of normal saline solution and continuous infusion of normal saline for 5 h. Postoperative bleeding and fibrinolytic activity were assessed. Hematologic data, convulsive seizures, allogeneic transfusion, occurrence of myocardial infarction, mortality, allergic reactions, postoperative renal insufficiency, and reopening rate were also evaluated. The placebo group had a greater postoperative blood loss (median (25th to 75th percentile) 12 h after surgery (540 (350-750) vs 300 (250-455) mL, P = 0.001). The placebo group also had greater blood loss 24 h after surgery (800 (520-1050) vs 500 (415-725) mL, P = 0.008). There was a significant increase in plasma D-dimer levels after coronary artery bypass grafting only in patients of the placebo group, whereas no significant changes were observed in the group treated with tranexamic acid. The D-dimer levels were 1057 (1025-1100) microg/L in the placebo group and 520 (435-837) microg/L in the tranexamic acid group (P = 0.01). We conclude that tranexamic acid effectively reduces postoperative bleeding and fibrinolysis in patients undergoing first-time coronary artery bypass grafting compared to placebo.