Drugs to Minimize Perioperative Blood Loss in Cardiac Surgery

Efficacy of antifibrinolytics in reducing blood loss during hip reconstruction surgery in cerebral palsy children. A systematic review and meta-analysis

BACKGROUND

Cerebral palsy (CP) children undergoing hip reconstruction are more prone to blood loss during surgery due to poor nutritional status, antiepileptic medication intake, depletion of clotting factors, and the extent of surgery involved. We conducted this present review to analyze whether antifibrinolytics during hip surgery in CP children would reduce surgical blood loss and transfusion requirements.

METHODS

Three databases (PubMed, EMBASE, and Cochrane library) were searched independently for publications mentioning the use of antifibrinolytics during hip reconstruction surgery in CP children. The primary outcome was to compare the surgical blood loss with and without antifibrinolytics use. Secondary outcomes were transfusion requirements, drop in hemoglobin level, length of hospital stay, and complication rates.

RESULTS

All five studies (reporting 478 patients) published on this topic were found eligible based on inclusion criteria and were included for final analysis. Primary outcome: In three of the included studies, antifibrinolytics use resulted in a significant reduction in total blood loss with a mean difference (MD) of -151.05 mL (95% CI -272.30 to -29.80, p = 0.01). In the other two studies although statistically not significant, antifibrinolytics use reduces estimated blood loss (MD: 3.27, 95% CI -21.44 to 14.91, p = 0.72). Secondary outcomes: We observed that in the antifibrinolytics group, there was a reduction in total blood transfusion requirements (OD: 0.70, 95% CI 0.35 to 1.37, p = 0.29), and a drop in haemoglobin level (MD: 0.16, 95% CI -0.62 to 0.30, p = 0.49) but statistically not significant. No adverse effects related directly to antifibrinolytics were noticed in all five studies.

CONCLUSION

Only two out of five included studies favored the use of antifibrinolytics in CP children undergoing hip reconstruction. The evidence synthesized on this meta-analysis is also not sufficient enough to support its routine use in this cohort of children for hip reconstruction surgery. High-quality studies with adequate sample size to determine the effective and safe dosage, timing, and cost involved of different antifibrinolytics are the need of the hour.

LEVEL OF EVIDENCE

Ⅲ.

Multiple trauma management in mountain environments - a scoping review : Evidence based guidelines of the International Commission for Mountain Emergency Medicine (ICAR MedCom). Intended for physicians and other advanced life support personnel

Background

Multiple trauma in mountain environments may be associated with increased morbidity and mortality compared to urban environments.

Objective

To provide evidence based guidance to assist rescuers in multiple trauma management in mountain environments.

Eligibility criteria

All articles published on or before September 30th 2019, in all languages, were included. Articles were searched with predefined search terms.

Sources of evidence

PubMed, Cochrane Database of Systematic Reviews and hand searching of relevant studies from the reference list of included articles.

Charting methods

Evidence was searched according to clinically relevant topics and PICO questions.

Results

Two-hundred forty-seven articles met the inclusion criteria. Recommendations were developed and graded according to the evidence-grading system of the American College of Chest Physicians. The manuscript was initially written and discussed by the coauthors. Then it was presented to ICAR MedCom in draft and again in final form for discussion and internal peer review. Finally, in a face-to-face discussion within ICAR MedCom consensus was reached on October 11th 2019, at the ICAR fall meeting in Zakopane, Poland.

Conclusions

Multiple trauma management in mountain environments can be demanding. Safety of the rescuers and the victim has priority. A crABCDE approach, with haemorrhage control first, is central, followed by basic first aid, splinting, immobilisation, analgesia, and insulation. Time for on-site medical treatment must be balanced against the need for rapid transfer to a trauma centre and should be as short as possible. Reduced on-scene times may be achieved with helicopter rescue. Advanced diagnostics (e.g. ultrasound) may be used and treatment continued during transport.

Desmopressin and bleeding risk after percutaneous kidney biopsy

Background

Desmopressin is used to reduce bleeding after kidney biopsy but evidence supporting its use is weak, especially in patients with elevated creatinine. The present study was undertaken to evaluate efficacy of desmopressin in reducing bleeding after percutaneous kidney biopsy.

Methods

Retrospective cohort study. 269 of 322 patients undergoing percutaneous kidney biopsy between January 1, 2014 and January 31, 2018 were included. Patients had normal bleeding time, platelet count and coagulation profile. Primary outcome was defined as composite of hemoglobin drop ≥1 g/dL, hematoma on post biopsy ultrasound, gross hematuria, erythrocyte transfusion or angiography to stop bleeding. Association of desmopressin with outcomes was assessed using linear (for continuous variables) and logistic (for binary variables) regression models. Propensity score was used to minimize potential confounding.

Results

Desmopressin was administered to 100/269 (37.17%) patients. After propensity score adjustment patients who received desmopressin had increased odds of post biopsy bleeding [OR 3.88 (1.95–7.74), p < 0.001]. Creatinine at time of biopsy influenced bleeding risk; gender, emergent vs elective biopsy, obesity, AKI, diabetes, hypertension or bleeding time did not influence bleeding risk. Administration of desmopressin to patients with serum creatinine ≥1.8 mg/dL decreased bleeding risk [OR 2.11 (95% CI 0.87–5.11), p = 0.09] but increased bleeding risk when serum creatinine was < 1.8 mg/dL (OR 9.72 (95% CI 2.95–31.96), p < 0.001).

Conclusion

Desmopressin should not be used routinely prior to percutaneous kidney biopsy in patients at low risk for bleeding but should be reserved for patients who are at high risk for bleeding.

Immunohistochemical Grading of Epidural Fibrosis with CD105 Antibody

OBJECTIVE

Grading of epidural fibrosis (EF) is usually performed by histopathologic staining in experimental studies. Immunohistochemical methods for grading are not available in routine practice yet. In our study, the effect of tranexamic acid (TXA), a commonly used hemostatic agent in surgical interventions, was evaluated for use against the development of EF with classical histopathologic methods and immunohistochemistry using the CD105 antibody, a marker of angiogenesis.

METHODS

Sixteen rats were used. The rats were assigned to 2 groups, control and TXA. Laminectomy was performed on the control group. In the treatment group, laminectomy + topical TXA was applied. After sacrificing the rats in the sixth week, histopathologic and immunohistochemical examinations and grading of the EF tissue were performed.

RESULTS

Conventional histopathologic parameters of fibroblast count, intensity of fibrosis density, and inflammatory cell density, as well as immunohistochemical evaluation with CD105, showed that the grading of EF was comparable between groups I and II (P < 0.001).

DISCUSSION

The results of our study have demonstrated that CD105 is compatible with the conventional histopathologic grading methods and can be used as a marker to determine the grades of angiogenesis and fibrosis in experimental studies. The results of our study have also shown that TXA, administered locally for hemostasis, reduces the grade of EF in rats following laminectomy. TXA has been observed to cause no toxic effects on neural tissue as it is already commonly used in clinical practice.

Anticoagulation, bleeding and blood transfusion practices in Australasian cardiac surgical practice

We surveyed contemporary Australasian cardiac surgical and anaesthetic practice, focusing on antiplatelet and antifibrinolytic therapies and blood transfusion practices. The cohort included 499 sequential adult cardiac surgical patients in 12 Australasian teaching hospitals. A total of 282 (57%) patients received red cell or component transfusion. The median (IQR) red cell transfusion threshold haemogloblin levels were 66 (61-73) g/l intraoperative^ and 79 (74-85) g/l postoperatively. Many (40%) patients had aspirin within five days of surgery but this was not associated with blood loss or transfusion; 15% had Clopidogrel within seven days of surgery. In all, 30 patients (6%) required surgical re-exploration for bleeding. Factors associated with transfusion and excessive bleeding include pre-existing renal impairment, preoperative Clopidogrel therapy, and complex or emergency surgery. Despite frequent (67%) use of antifibrinolytic therapy, there was a marked variability in red cell transfusion rates between centres (range 17 to 79%, P <0.001). This suggests opportunities for improvement in implementation of guidelines and effective blood-sparing interventions. Many patients presenting for surgery receive antiplatelet and/or antifibrinolytic therapy, yet the subsequent benefits and risks remain unclear.

Use of Intravenous Tranexamic Acid to Reduce Allogeneic Blood Transfusion in Total Hip and Knee Arthroplasty: A Meta-analysis

Total hip or knee arthroplasty is associated with significant blood loss. Techniques such as the use of antifibrinolytics or desmopressin, or normovolaemic haemodilution have been used to reduce the need for allogeneic blood transfusion. Tranexamic acid has been used to reduce blood loss and transfusion requirement for total hip and knee arthroplasty, with variable results. This meta-analysis aims to evaluate whether intravenous tranexamic acid, when compared with placebo, reduces blood loss and transfusion requirement in total hip and knee joint replacement surgery and whether it might increase the risk of thromboembolic complications. The literature search was based on MEDLINE, EMBASE, Cochrane Controlled Trials Register, and information from the pharmaceutical company that produces tranexamic acid (Pharmacia-Upjohn). We identified 15 clinical trials and 12 were considered suitable for detailed data extraction. Tranexamic acid reduces the proportion of patients requiring allogeneic blood transfusion (OR 0.16, 95% CI: 0.09–0.26), total amount of blood loss (WMD 460 ml, 95% CI: 274–626 ml), and the total number of units of allogeneic blood transfused (WMD 0.85 unit, 95% CI: 0.36–1.33). Tranexamic acid does not increase the risk of thromboemobolic complications such as deep vein thrombosis, pulmonary embolism, thrombotic cerebral vascular accident, or myocardial infarction (OR 0.98, 95% CI: 0.45–2.12). Intravenous tranexamic acid appears effective and safe in reducing allogeneic blood transfusion and blood loss in total hip and knee arthroplasty.

The effect of tranexamic acid to reduce blood loss and transfusion on off-pump coronary artery bypass surgery: A systematic review and cumulative meta-analysis

STUDY OBJECTIVE

To assess the safety and efficacy of tranexamic acid (TA) on off-pump coronary artery bypass (OPCAB) surgery.

DESIGN

Meta-analysis.

SETTING

Operating room, OPCAB surgery, all surgeries were elective measurements. Searching the following data sources respectively: PubMed/MEDLINE, the Cochrane Library, EMBASE and reference lists of identified articles, we performed a meta-analysis of postoperative 24h blood loss, postoperative allogeneic transfusion, re-operation for massive bleeding, postoperative mortality, and postoperative thrombotic complications.

MAIN RESULTS

Using electronic databases, we selected 15 randomized control trials (RCTs), carried out between 2003 and 2016, with a total of 1250 patients for our review. TA significantly reduced the postoperative 24h blood loss (mean difference -213.32ml, 95% confidence intervals, -247.20ml to -179.43ml; P<0.0001). And, TA also significantly reduced the risk of packed red blood cell (PRBCs) transfusion (risk ratio 0.62; 95% confidence intervals 0.51 to 0.76; P<0.0001) and fresh frozen plasma (FFP) transfusion (0.65; 0.52 to 0.81; P<0.001). There were no statistical significance on platelet transfusion (risk difference -0.00, 95% confidence interval -0.02 to 0.02; P=0.73) and re-operation (0.00, -0.02 to 0.02; P=1.00). No association was found between TA and morbility (risk difference -0.00, 95% confidence interval -0.02 to 0.02; P=0.99) and thrombotic complications (-0.01, -0.01 to 0.02; P=0.70).

CONCLUSIONS

TA reduced the probability of receiving a PRBCs and FFP transfusion during OPCAB surgery. And no association with postoperative death and thrombotic events was found. However, further trials with an appropriate sample size are required to confirm TA safety in OPCAB surgery.

Hemostatic Agents in Critically Ill Patients

How to cite this article: Das SK, Reddy MM, Ray S. Hemostatic Agents in Critically Ill Patients. Indian J Crit Care Med 2019;23(Suppl 3):S226–S229.

The use of fibrin sealant during non-emergency surgery: a systematic review of evidence of benefits and harms

BACKGROUND

Fibrin sealants are used in different types of surgery to prevent the accumulation of post-operative fluid (seroma) or blood (haematoma) or to arrest haemorrhage (bleeding). However, there is uncertainty around the benefits and harms of fibrin sealant use.

OBJECTIVES

To systematically review the evidence on the benefits and harms of fibrin sealants in non-emergency surgery in adults.

DATA SOURCES

Electronic databases [MEDLINE, EMBASE and The Cochrane Library (including the Cochrane Database of Systematic Reviews, the Database of Abstracts of Reviews of Effects, the Health Technology Assessment database and the Cochrane Central Register of Controlled Trials)] were searched from inception to May 2015. The websites of regulatory bodies (the Medicines and Healthcare products Regulatory Agency, the European Medicines Agency and the Food and Drug Administration) were also searched to identify evidence of harms.

REVIEW METHODS

This review included randomised controlled trials (RCTs) and observational studies using any type of fibrin sealant compared with standard care in non-emergency surgery in adults. The primary outcome was risk of developing seroma and haematoma. Only RCTs were used to inform clinical effectiveness and both RCTs and observational studies were used for the assessment of harms related to the use of fibrin sealant. Two reviewers independently screened all titles and abstracts to identify potentially relevant studies. Data extraction was undertaken by one reviewer and validated by a second. The quality of included studies was assessed independently by two reviewers using the Cochrane Collaboration risk-of-bias tool for RCTs and the Centre for Reviews and Dissemination guidance for adverse events for observational studies. A fixed-effects model was used for meta-analysis.

RESULTS

We included 186 RCTs and eight observational studies across 14 surgical specialties and five reports from the regulatory bodies. Most RCTs were judged to be at an unclear risk of bias. Adverse events were inappropriately reported in observational studies. Meta-analysis across non-emergency surgical specialties did not show a statistically significant difference in the risk of seroma for fibrin sealants versus standard care in 32 RCTs analysed [n = 3472, odds ratio (OR) 0.84, 95% confidence interval (CI) 0.68 to 1.04; p = 0.13; I² = 12.7%], but a statistically significant benefit was found on haematoma development in 24 RCTs (n = 2403, OR 0.62, 95% CI 0.44 to 0.86; p = 0.01; I² = 0%). Adverse events related to fibrin sealant use were reported in 10 RCTs and eight observational studies across surgical specialties, and 22 RCTs explicitly stated that there were no adverse events. One RCT reported a single death but no other study reported mortality or any serious adverse events. Five regulatory body reports noted death from air emboli associated with fibrin sprays.

LIMITATIONS

It was not possible to provide a detailed evaluation of individual RCTs in their specific contexts because of the limited resources that were available for this research. In addition, the number of RCTs that were identified made it impractical to conduct independent data extraction by two reviewers in the time available.

CONCLUSIONS

The effectiveness of fibrin sealants does not appear to vary according to surgical procedures with regard to reducing the risk of seroma or haematoma. Surgeons should note the potential risk of gas embolism if spray application of fibrin sealants is used and not to exceed the recommended pressure and spraying distance. Future research should be carried out in surgery specialties for which only limited data were found, including neurological, gynaecological, oral and maxillofacial, urology, colorectal and orthopaedics surgery (for any outcome); breast surgery and upper gastrointestinal (development of haematoma); and cardiothoracic heart or lung surgery (reoperation rates). In addition, studies need to use adequate sample sizes, to blind participants and outcome assessors, and to follow reporting guidelines.

STUDY REGISTRATION

This study is registered as PROSPERO CRD42015020710.

FUNDING

The National Institute for Health Research Health Technology Assessment programme.

Biomaterials and Advanced Technologies for Hemostatic Management of Bleeding

Bleeding complications arising from trauma, surgery, and as congenital, disease-associated, or drug-induced blood disorders can cause significant morbidities and mortalities in civilian and military populations. Therefore, stoppage of bleeding (hemostasis) is of paramount clinical significance in prophylactic, surgical, and emergency scenarios. For externally accessible injuries, a variety of natural and synthetic biomaterials have undergone robust research, leading to hemostatic technologies including glues, bandages, tamponades, tourniquets, dressings, and procoagulant powders. In contrast, treatment of internal noncompressible hemorrhage still heavily depends on transfusion of whole blood or blood's hemostatic components (platelets, fibrinogen, and coagulation factors). Transfusion of platelets poses significant challenges of limited availability, high cost, contamination risks, short shelf-life, low portability, performance variability, and immunological side effects, while use of fibrinogen or coagulation factors provides only partial mechanisms for hemostasis. With such considerations, significant interdisciplinary research endeavors have been focused on developing materials and technologies that can be manufactured conveniently, sterilized to minimize contamination and enhance shelf-life, and administered intravenously to mimic, leverage, and amplify physiological hemostatic mechanisms. Here, a comprehensive review regarding the various topical, intracavitary, and intravenous hemostatic technologies in terms of materials, mechanisms, and state-of-art is provided, and challenges and opportunities to help advancement of the field are discussed.

Desmopressin use for minimising perioperative blood transfusion

BACKGROUND

Blood transfusion is administered during many types of surgery, but its efficacy and safety are increasingly questioned. Evaluation of the efficacy of agents, such as desmopressin (DDAVP; 1-deamino-8-D-arginine-vasopressin), that may reduce perioperative blood loss is needed.

OBJECTIVES

To examine the evidence for the efficacy of DDAVP in reducing perioperative blood loss and the need for red cell transfusion in people who do not have inherited bleeding disorders.

SEARCH METHODS

We searched for randomised controlled trials (RCTs) in the Cochrane Central Register of Controlled Trials (2017, issue 3) in the Cochrane Library, MEDLINE (from 1946), Embase (from 1974), the Cumulative Index to Nursing and Allied Health Literature (CINAHL) (from 1937), the Transfusion Evidence Library (from 1980), and ongoing trial databases (all searches to 3 April 2017).

SELECTION CRITERIA

We included randomised controlled trials comparing DDAVP to placebo or an active comparator (e.g. tranexamic acid, aprotinin) before, during, or immediately after surgery or after invasive procedures in adults or children.

DATA COLLECTION AND ANALYSIS

We used the standard methodological procedures expected by Cochrane.

MAIN RESULTS

We identified 65 completed trials (3874 participants) and four ongoing trials. Of the 65 completed trials, 39 focused on adult cardiac surgery, three on paediatric cardiac surgery, 12 on orthopaedic surgery, two on plastic surgery, and two on vascular surgery; seven studies were conducted in surgery for other conditions. These trials were conducted between 1986 and 2016, and 11 were funded by pharmaceutical companies or by a party with a commercial interest in the outcome of the trial.The GRADE quality of evidence was very low to moderate across all outcomes. No trial reported quality of life. DDAVP versus placebo or no treatmentTrial results showed considerable heterogeneity between surgical settings for total volume of red cells transfused (low-quality evidence) and for total blood loss (very low-quality evidence) due to large differences in baseline blood loss. Consequently, these outcomes were not pooled and were reported in subgroups.Compared with placebo, DDAVP may slightly decrease the total volume of red cells transfused in adult cardiac surgery (mean difference (MD) -0.52 units, 95% confidence interval (CI) -0.96 to -0.08 units; 14 trials, 957 participants), but may lead to little or no difference in orthopaedic surgery (MD -0.02, 95% CI -0.67 to 0.64 units; 6 trials, 303 participants), vascular surgery (MD 0.06, 95% CI -0.60 to 0.73 units; 2 trials, 135 participants), or hepatic surgery (MD -0.47, 95% CI -1.27 to 0.33 units; 1 trial, 59 participants).DDAVP probably leads to little or no difference in the total number of participants transfused with blood (risk ratio (RR) 0.96, 95% CI 0.86 to 1.06; 25 trials; 1806 participants) (moderate-quality evidence).Whether DDAVP decreases total blood loss in adult cardiac surgery (MD -135.24 mL, 95% CI -210.80 mL to -59.68 mL; 22 trials, 1358 participants), orthopaedic surgery (MD -285.76 mL, 95% CI -514.99 mL to -56.53 mL; 5 trials, 241 participants), or vascular surgery (MD -582.00 mL, 95% CI -1264.07 mL to 100.07 mL; 1 trial, 44 participants) is uncertain because the quality of evidence is very low.DDAVP probably leads to little or no difference in all-cause mortality (Peto odds ratio (pOR) 1.09, 95% CI 0.51 to 2.34; 22 trials, 1631 participants) or in thrombotic events (pOR 1.36, 95% CI, 0.85 to 2.16; 29 trials, 1984 participants) (both low-quality evidence). DDAVP versus placebo or no treatment for people with platelet dysfunctionCompared with placebo, DDAVP may lead to a reduction in the total volume of red cells transfused (MD -0.65 units, 95% CI -1.16 to -0.13 units; 6 trials, 388 participants) (low-quality evidence) and in total blood loss (MD -253.93 mL, 95% CI -408.01 mL to -99.85 mL; 7 trials, 422 participants) (low-quality evidence).DDAVP probably leads to little or no difference in the total number of participants receiving a red cell transfusion (RR 0.83, 95% CI 0.66 to 1.04; 5 trials, 258 participants) (moderate-quality evidence).Whether DDAVP leads to a difference in all-cause mortality (pOR 0.72, 95% CI 0.12 to 4.22; 7 trials; 422 participants) or in thrombotic events (pOR 1.58, 95% CI 0.60 to 4.17; 7 trials, 422 participants) is uncertain because the quality of evidence is very low. DDAVP versus tranexamic acidCompared with tranexamic acid, DDAVP may increase the volume of blood transfused (MD 0.6 units, 95% CI 0.09 to 1.11 units; 1 trial, 40 participants) and total blood loss (MD 142.81 mL, 95% CI 79.78 mL to 205.84 mL; 2 trials, 115 participants) (both low-quality evidence).Whether DDAVP increases or decreases the total number of participants transfused with blood is uncertain because the quality of evidence is very low (RR 2.42, 95% CI 1.04 to 5.64; 3 trials, 135 participants).No trial reported all-cause mortality.Whether DDAVP leads to a difference in thrombotic events is uncertain because the quality of evidence is very low (pOR 2.92, 95% CI 0.32 to 26.83; 2 trials, 115 participants). DDAVP versus aprotininCompared with aprotinin, DDAVP probably increases the total number of participants transfused with blood (RR 2.41, 95% CI 1.45 to 4.02; 1 trial, 99 participants) (moderate-quality evidence).No trials reported volume of blood transfused or total blood loss and the single trial that included mortality as an outcome reported no deaths.Whether DDAVP leads to a difference in thrombotic events is uncertain because the quality of evidence is very low (pOR 0.98, 95% CI 0.06 to 15.89; 2 trials, 152 participants).

AUTHORS' CONCLUSIONS

Most of the evidence derived by comparing DDAVP versus placebo was obtained in cardiac surgery, where DDAVP was administered after cardiopulmonary bypass. In adults undergoing cardiac surgery, the reduction in volume of red cells transfused and total blood loss was small and was unlikely to be clinically important. It is less clear whether DDAVP may be of benefit for children and for those undergoing non-cardiac surgery. A key area for researchers is examining the effects of DDAVP for people with platelet dysfunction. Few trials have compared DDAVP versus tranexamic acid or aprotinin; consequently, we are uncertain of the relative efficacy of these interventions.

Randomized controlled trials of aprotinin in cardiac surgery: could clinical equipoise have stopped the bleeding?

Background Aprotinin is a serine protease inhibitor used to limit perioperative bleeding and reduce the need for donated blood transfusions during cardiac surgery. Randomized controlled trials of aprotinin evaluating its effect on the outcome of perioperative transfusion have been published since 1987, and systematic reviews were conducted in 1992 and 1997.

Methods A systematic search was conducted for all RCTs of aprotinin that used placebo controls or were open-label with no active control treatment. Data collected included the primary outcome, objective of each study, whether a systematic review was cited or conducted as part of the background and/or rationale for the study and the number of previously published RCTs cited. Cumulative meta-analyses were performed.

Results Sixty-four randomized, controlled trials of aprotinin were found, conducted between 1987 and 2002, reporting an endpoint of perioperative transfusion. Median trial size was 64 subjects, with a range of 20 to 1784. A cumulative meta-analysis indicated that aprotinin greatly decreased the need for perioperative transfusion, stabilizing at an odds ratio of 0.25 (p, 10 2 6) by the 12th study, published in June of 1992. The upper limit of the confidence interval never exceeded 0.65 and results were similar in all subgroups. Citation of previous RCTs was extremely low, with a median of 20% of prior trials cited. Only 7 of 44 (15%) of subsequent reports referenced the largest trial (N 1/4 1784), which was 28 times larger than the median trial size.

Conclusions This study demonstrates that investigators evaluating aprotinin were not adequately citing previous research, resulting in a large number of RCTs being conducted to address efficacy questions that prior trials had already definitively answered. Institutional review boards and journals could reduce the number of redundant trials by requiring investigators to conduct adequate searches for prior evidence and conducting systematic reviews.

The Safety and Efficacy of “Bloodless” Cardiac Surgery

Nearly 20% of blood transfusions in the United States are associated with cardiac surgery. Despite the many blood conservation techniques that are available, safe, and efficacious for patients undergoing cardiac surgery, many of these operations continue to be associated with significant amounts of blood transfusion. Although surgical bleeding after cardiopulmonary bypass is a common problem as reflected by the substantial use of blood products, it is the individual physician and institutional behavior that have been identified as reasons for transfusion and not necessarily patient comorbidity or blood loss. Transfusion rates in cardiac surgery remain high despite major advances in perioperative blood conservation, with large variations among individual centers. The adoption of available blood conservation techniques, either alone or in combination in patients undergoing cardiac surgery, could result in an estimated 75% reduction of unnecessary transfusions. The success of previously reported blood conservations programs in cardiac surgery should call for a reevaluation of allogeneic transfusion practices in patients undergoing cardiac surgery. By applying the numerous reported blood conservation strategies for the management of patients presenting for cardiac surgery, we can preserve our dwindling blood resources and help alleviate some of the direct costs of blood as well as the indirect costs of treating noninfectious and infectious complications of transfusion.

Blood Conservation Strategies in Cardiac Surgery

Perioperative bleeding in cardiac surgery is related to both surgical trauma of blood vessels and defects in the hemostatic mechanism caused, in part, by cardiopulmonary bypass. Blood transfusion therefore remains a significant risk of cardiac surgery with important health and economic consequences. Blood conservation strategies for cardiac surgery have advanced over the years and the following discussion will focus on the current practices at Toronto General Hospital.

Bleeding Following Deep Hypothermia and Circulatory Arrest in Children

Deep hypothermic circulatory arrest (DHCA) is a technique of extracorporeal circulation commonly used in children with complex congenital heart defects undergoing surgical repairs. The use of profound cooling (20°C) and complete cessation of circulation allow adequate exposure and correction of these complex lesions, with enhanced cerebral protection. However, the profound physiologic state of DHCA results in significant derangement of the coagulation system and a high incidence of postoperative bleeding. This review examines the impact of DHCA on bleeding and transfusion requirements in children and the pathophysiology of DHCA-induced platelet dysfunction. It also focuses on possible pharmacologic interventions to decrease bleeding following DHCA in children.

Optimal Management of Bleeding Complications After Cardiac Surgery

Patients undergoing cardiac surgery with cardiopulmo nary bypass (CPB) are at increased risk for excessive perioperative blood loss requiring transfusion of blood products. Point-of-care evaluation of platelets, coagu lation factors, and fibrinogen can enable physicians to assess bleeding abnormalities rapidly. They also can facilitate the optimal administration of pharmacologic and transfusion-based therapy and allow physicians to identify patients with surgical bleeding. The ability to reduce the unnecessary use of blood products in this setting has important implications for emerging issues in blood inventory and blood costs. The ability to de crease operative time along with re-exploration rates has important consequences for health care costs in an increasingly managed health care environment. Copyright© 2001 by W.B. Saunders Company.

The Effect of Desmopressin on the Amount of Bleeding in Patients Undergoing Coronary Artery Bypass Graft Surgery with a Cardiopulmonary Bypass Pump After Taking Anti-Platelet Medicine

Background

Coronary artery bypass grafting (CABG) is a common surgical intervention at the end-stages of coronary artery occlusion disease. Despite the effectiveness of CABG, it may have particular complications, such as bleeding during and after surgery. So far, there have been many drugs used to reduce bleeding.

Objectives

This study aimed at investigating the effects of desmopressin on the amount of bleeding in patients undergoing CABG with a cardiopulmonary bypass pump (CPBP) who were taking anti-platelet medicine.

Methods

One hundred patients scheduled for elective CABG with a CPBP were included in a prospective, placebo-controlled, double-blinded clinical trial study. They were randomly divided into two groups. One group received desmopressin (40 μg) and the other group received a placebo (isotonic saline). Seven patients were excluded from the study, and 47 and 46 patients participated in the desmopressin and control groups, respectively. The methods of monitoring and the anesthetic techniques were similar in both groups, and all surgeries were performed by one surgeon. Variables including age, gender, pump time, aortic clamp time, duration of surgery, complications (e.g., nausea and vomiting, blood pressure changes), the necessity to receive blood products, and coagulation tests (prothrombin time, partial thromboplastin time, international normalized ratio, and bleeding time) were assessed. Data were statistically analyzed with SPSS software version 17.

Results

There was no significant difference between the groups regarding age, gender, pump time, clamp time, duration of surgery, complications, and the changes in hemoglobin and coagulation test measurements (P > 0.05). No significant difference was noted between the groups regarding the rate of bleeding after surgery (359.3 ± 266.2 in group D vs. 406.3 ± 341.6 in group P (control group); P = 0.208). However, the platelet changes after surgery in both groups were significantly different. The analysis revealed that the rate of thrombocytopenia after surgery was higher in the control group (P = 0.012).

Conclusions

Our study showed that desmopressin could not reduce the amount of blood loss after CABG. Also, desmopressin did not have a significant effect on coagulation status. Therefore, based on the results of our study, it seems that the use of this medication cannot be a helpful for patients with any indication for CABG.

The European guideline on management of major bleeding and coagulopathy following trauma: fourth edition

BACKGROUND

Severe trauma continues to represent a global public health issue and mortality and morbidity in trauma patients remains substantial. A number of initiatives have aimed to provide guidance on the management of trauma patients. This document focuses on the management of major bleeding and coagulopathy following trauma and encourages adaptation of the guiding principles to each local situation and implementation within each institution.

METHODS

The pan-European, multidisciplinary Task Force for Advanced Bleeding Care in Trauma was founded in 2004 and included representatives of six relevant European professional societies. The group used a structured, evidence-based consensus approach to address scientific queries that served as the basis for each recommendation and supporting rationale. Expert opinion and current clinical practice were also considered, particularly in areas in which randomised clinical trials have not or cannot be performed. Existing recommendations were reconsidered and revised based on new scientific evidence and observed shifts in clinical practice; new recommendations were formulated to reflect current clinical concerns and areas in which new research data have been generated. This guideline represents the fourth edition of a document first published in 2007 and updated in 2010 and 2013.

RESULTS

The guideline now recommends that patients be transferred directly to an appropriate trauma treatment centre and encourages use of a restricted volume replacement strategy during initial resuscitation. Best-practice use of blood products during further resuscitation continues to evolve and should be guided by a goal-directed strategy. The identification and management of patients pre-treated with anticoagulant agents continues to pose a real challenge, despite accumulating experience and awareness. The present guideline should be viewed as an educational aid to improve and standardise the care of the bleeding trauma patients across Europe and beyond. This document may also serve as a basis for local implementation. Furthermore, local quality and safety management systems need to be established to specifically assess key measures of bleeding control and outcome.

CONCLUSIONS

A multidisciplinary approach and adherence to evidence-based guidance are key to improving patient outcomes. The implementation of locally adapted treatment algorithms should strive to achieve measureable improvements in patient outcome.

Effects of intravenous administration of tranexamic acid on hematological, hemostatic, and thromboelastographic analytes in healthy adult dogs

OBJECTIVE

To assess the effects of tranexamic acid (TA) on hematological, hemostatic, and thromboelastographic analytes in healthy adult dogs.

DESIGN

Prospective study.

SETTING

University teaching hospital.

ANIMALS

Eleven healthy, staff-owned, adult dogs.

MEASUREMENTS AND MAIN RESULTS

Dogs were administered TA as an IV bolus, followed by a 3-hour constant rate infusion (CRI). Complete blood count, prothrombin time, activated partial thromboplastin time, D-dimer, antithrombin, fibrinogen, and thromboelastography (TEG) were measured prior to, and immediately after TA administration. Vomiting occurred transiently in the first 2 treated dogs, immediately after 20 and 15 mg/kg IV boluses, but not during the CRI. In all other dogs the TA IV bolus dose was reduced to 10 mg/kg, and administered slower, and vomiting did not occur. All measured hemostatic and hematological analytes remained within their reference intervals, however, following TA treatment, significant decreases were recorded in prothrombin time, TEG R and A30 values, Hct, and hemoglobin concentration, while the TEG LY30 significantly increased.

CONCLUSIONS

Administration of TA as a slow IV bolus at 10 mg/kg, followed by a 10 mg/kg/h CRI over 3 hours to healthy dogs is safe; however, its effect on TEG A30, A60, LY30, and LY60 values was inconsistent with its expected anti-fibrinolytic properties.

Prophylactic intraoperative tranexamic acid administration and postoperative blood loss after transapical aortic valve implantation

Objectives

Antifibrinolytics are widely used in cardiac surgery to save blood perioperatively. In the present study we evaluated the hemostatic effects of tranexamic acid (TXA) to decrease bleeding tendency and transfusion requirements in high-risk patients following transapical aortic valve implantation (TA-AVI).

Methods

A retrospective analysis was performed on aortic stenosis patients undergoing TA-AVI with or without intraoperative TXA administration to determine postoperative blood loss and transfusion requirements. From January 2009 to August 2010 in total 92 patients were treated without intraoperative TXA administration, from August 2010 to July 2011 54 patients received TXA intraoperatively.

Results

Early postoperative (24 h) blood loss was significantly lower in TXA-group than in non-TXA group (327 ± 274 mL vs. 481.1 ± 318.8 mL; p = 0.003). In the TXA group 53.7% of patients received allogeneic blood products during the hospital stay as compared to 72.8% in the non-TXA group (p = 0.242). TXA group required fewer transfusions (2.1 ± 1.9 vs. 2.9 ± 3.5 Units; p = 0.046) and had no increased incidence of thrombotic or neurological complications. There was no significant difference in the length of ICU, hospital stay, or 30-day mortality. Administration of tranexamic acid was found to be significantly associated with lower blood loss postoperatively (p = 0.002). Furthermore, there was a significant correlation between the postoperative blood loss (p = 0.036) and red blood cell transfusion (p = 0.001) with 30-day mortality.

Conclusion

Low dose prophylactic intraoperative administration of tranexamic acid appears to be effective in reducing postoperative bleeding and the need for allogeneic blood products following TA-AVI.

Tranexamic acid for upper gastrointestinal bleeding

Background Tranexamic acid reduces haemorrhage through its antifibrinolytic effects. In a previous version of the present review, we found that tranexamic acid may reduce mortality. This review includes updated searches and new trials.Objectives To assess the effects of tranexamic acid versus no intervention, placebo or other antiulcer drugs for upper gastrointestinal bleeding.Search methods We updated the review by performing electronic database searches (Cochrane Central Register of Controlled Trials (CENTRAL),MEDLINE, EMBASE, Science Citation Index) and manual searches in July 2014.Selection criteriaRandomised controlled trials, irrespective of language or publication status.Data collection and analysis We used the standard methodological procedures of the The Cochrane Collaboration. All-cause mortality, bleeding and adverse events were the primary outcome measures. We performed fixed-effect and random-effects model meta-analyses and presented results as risk ratios (RRs) with 95% confidence intervals (CIs) and used I² as a measure of between-trial heterogeneity. We analysed tranexamic acid versus placebo or no intervention and tranexamic acid versus antiulcer drugs separately. To analyse sources of heterogeneity and robustness of the overall results, we performed subgroup, sensitivity and sequential analyses.Main results We included eight randomised controlled trials on tranexamic acid for upper gastrointestinal bleeding. Additionally, we identified one large ongoing pragmatic randomised controlled trial from which data are not yet available. Control groups were randomly assigned to placebo (seven trials) or no intervention (one trial). Two trials also included a control group randomly assigned to antiulcer drugs(lansoprazole or cimetidine). The included studies were published from 1973 to 2011. The number of participants randomly assigned ranged from 47 to 216 (median 204). All trials reported mortality. In total, 42 of 851 participants randomly assigned to tranexamic acid and 71 of 850 in the control group died (RR 0.60, 95% CI 0.42 to 0.87; P value 0.007; I² = 0%). The analysis was not confirmed when all participants in the intervention group with missing outcome data were included as treatment failures, or when the analysis was limited to trials with low risk of attrition bias. Rebleeding was diagnosed for 117 of 826 participants in the tranexamic acid group and for 146 of 825 participants in the control group (RR 0.80, 95% CI 0.64 to 1.00; P value 0.07; I² = 49%).We were able to evaluate the risk of serious adverse events on the basis of only four trials. Our analyses showed 'no evidence of a difference between tranexamic acid and control interventions regarding the risk of thromboembolic events.’ Tranexamic acid appeared to reduce the risk of surgery ina fixed-effect meta-analysis (RR 0.73, 95% CI 0.56 to 0.95), but this result was no longer statistically significant in a random-effects meta-analysis (RR 0.61, 95% CI 0.35 to 1.04; P value 0.07). No difference was apparent between tranexamic acid and placebo in the assessment of transfusion (RR 1.02, 95% CI 0.94 to 1.11; I² = 0%), and meta-analyses that compared tranexamic acid versus antiulcer drugs did not identify beneficial or detrimental effects of tranexamic acid for any of the outcomes assessed.Authors' conclusions This review found that tranexamic acid appears to have a beneficial effect on mortality, but a high dropout rate in some trials means that we cannot be sure of this until the findings of additional research are published. At the time of this update in 2014, one large study(8000 participants) is in progress, so this review will be much more informative in a few years. Further examination of tranexamic acid would require inclusion of high-quality randomised controlled trials. Timing of randomisation is essential to avoid attrition bias and to limit the number of withdrawals. Future trials may use a pragmatic design and should include all participants with suspected bleeding or with endoscopically verified bleeding, as well as a tranexamic placebo arm and co-administration of pump inhibitors and endoscopic therapy. Assessment of outcome measures in such studies should be clearly defined. Endoscopic examination with appropriate control of severe bleeding should be performed, as should endoscopic verification of clinically significant rebleeding. In addition, clinical measures of rebleeding should be included. Other important outcome measures include mortality (30-day or in-hospital), need for emergency surgery or blood transfusion and adverse events (major or minor).

A 2014 Update on Coagulation Management for Cardiopulmonary Bypass

Coagulopathy after cardiac surgery with cardiopulmonary bypass is a serious complication that may result in massive bleeding requiring transfusion of significant amounts of blood products, plasma, and platelets. In addition to increased patient morbidity and mortality it is associated with longer hospital stay and increased resource utilization. The current review discusses aspects in cardiopulmonary bypass–induced coagulopathy with emphasis on point-of-care testing and individualized “goal-directed” therapy in patients who develop excessive bleeding after cardiac surgery.

Low dose tranexamic acid effect on post-coronary artery bypass grafting bleeding

Objective

This study investigated the effects of low-dose tranexamic acid on post-coronary artery bypass surgery bleeding .

Background

Diffuse microvascular bleeding is still a common problem after cardiac procedures. This study was designed to evaluate the hemostatic effects of low-dose tranexamic acid in on-pump coronary artery bypass graft surgery.

Methods

In this prospective randomized placebo-controlled study, 150 patients who were candidates for coronary artery bypass were enrolled and randomly assigned to 1 of 2 groups (tranexamic acid or placebo). Total drainage volume and the need for transfusion as well as surgical complications were recorded and compared in the 2 groups.

Results

There was significantly less mediastinal chest tube drainage up to 48 h in the tranexamic acid group (432 ± 210 mL) compared to the placebo group (649 ± 235 mL, p = 0.006). In the placebo group, 43 (58%) patients were given allogeneic blood during hospital stay compared to 22 (25%) in the tranexamic acid group ( p < 0.001). No significant difference in postoperative complications was seen.

Conclusion

The use of low-dose tranexamic acid can significantly reduce blood loss and need for transfusion, with no increase in complications.

Use of point-of-care testing for plasma therapy

Use of point-of-care testing (POCT) has been driven by limitations of laboratory-based testing as a tool for decisions for transfusions of blood components. Clinical settings such as liver transplantation, cardiothoracic surgery, and trauma are particularly in need of such diagnostic tests because of the complex coagulopathies that can develop in these settings of substantial hemorrhage and need for blood component support. Successful implementation of POCT requires collaboration between surgery, anesthesia, critical care, and the laboratory to ensure proper quality control of equipment, operator training and competency, medical records test results, billing procedures, and consensus-derived transfusion algorithms for cost-effective, targeted blood component transfusion support. In this review we summarize clinical evidence for the effectiveness of POCT, along with some future directions for this strategy.

Tranexamic acid reduces blood transfusions in elderly patients undergoing combined aortic valve and coronary artery bypass graft surgery: a randomized controlled trial

OBJECTIVE

To evaluate the effects of tranexamic acid on postoperative blood loss and transfusion requirements in elderly patients undergoing combined aortic valve replacement and coronary artery bypass graft surgery (CABG).

DESIGN

A prospective, randomized, double-blinded, placebo-controlled, parallel-group trial.

SETTING

A university hospital (single institution).

PARTICIPANTS

Sixty-four patients 70 years or older undergoing combined aortic valve replacement and CABG surgery were included. One patient was withdrawn from the study after randomization by the attending surgeon because of a change in the surgical procedure. The remaining 63 patients were analyzed as intention to treat.

INTERVENTIONS

The included patients were randomized to treatment with either tranexamic acid, 10 mg/kg, as a bolus injection before surgery followed by 1 mg/kg/h as an infusion during surgery, or a corresponding volume of 0.9% sodium chloride.

MEASUREMENTS AND MAIN RESULTS

Postoperative blood loss was recorded for 16 hours. The transfusion of blood products was recorded during the entire hospital stay. The number of packed red cell transfusions given to the patients was significantly lower in the tranexamic acid group compared with the placebo group (median, 3.0 [interquartile range, 2-5] v 5.0 [3-7], p = 0.049).

CONCLUSION

Tranexamic acid reduced the number of packed red cell transfusions given to patients 70 years or older undergoing combined aortic valve replacement and CABG surgery.

Tranexamic acid for upper gastrointestinal bleeding

BACKGROUND

Tranexamic acid reduces haemorrhage through its antifibrinolytic effects. In a previous version of the present review, we found that tranexamic acid may reduce mortality. The present review includes updated searches of randomised trials on tranexamic acid versus placebo, cimetidine or lansoprazole.

OBJECTIVES

To assess the effects of tranexamic acid for upper gastrointestinal bleeding.

SEARCH METHODS

Electronic searches (The Cochrane Library, MEDLINE, EMBASE, Science Citation Index) and manual searches were combined. The last search update was in October 2011.

SELECTION CRITERIA

Trials in which patients with upper gastrointestinal bleeding were randomised to receive either tranexamic acid or placebo, or any anti-ulcer drug, were included.

DATA COLLECTION AND ANALYSIS

Two authors independently extracted data. All-cause mortality was the primary outcome measure. Random-effects model meta-analyses were performed and results presented as relative risks (RR) with 95% confidence intervals (CI). Subgroup, sensitivity, regression and sequential analyses were performed to analyse sources of intertrial heterogeneity and the robustness of the overall result.

MAIN RESULTS

Seven double blind randomised trials on tranexamic acid versus placebo, cimetidine, or lanzoprazole were included. One trial offered endoscopic treatment to all patients that were randomised. Random-effects model meta-analysis found that tranexmic acid reduced mortality compared with placebo (41 of 829 versus 68 of 825 patients; RR: 0.61, 95% CI 0.42 to 0.89). The beneficial effect was not confirmed in subgroup analysis stratified for the quality of bias control, in worst case scenario analyses (in which 21% of the randomised patients were excluded), or in sequential analyses. No significant differences were found between tranexamic acid and placebo on bleeding, surgery, or transfusion requirements. No clear effects of tranexamic acid were identified in trials using endoscopic therapy or in the trials comparing tranexamic acid with cimetidine or lansoprazole. In the tranexamic acid group, five cases of serious thromboembolic events occurred (myocardial infarction, pulmonary embolism, and cerebral infarction). Overall, the number of patients with any thrombotic event was not significantly increased in the tranexamic acid group (RR 1.87, 95% CI 0.60 to 5.85).

AUTHORS' CONCLUSIONS

Considering the internal and external validity of the evidence, tranexamic acid cannot be recommended for routine use. Additional trials in which tranexamic acid is used in combination with the currently recommended interventions are required.

A case report and brief review of the literature on bilateral retinal infarction following cardiopulmonary bypass for coronary artery bypass grafting

Postoperative visual loss is a devastating perioperative complication. The commonest aetiologies are anterior ischaemic optic neuropathy (AION), posterior ischaemic optic neuropathy (PION), and central retinal artery occlusion (CRAO). These appear to be related to certain types of operation, most commonly spinal and cardiac bypass procedures; with the rest divided between: major trauma causing excessive blood loss; head/neck and nasal or sinus surgery; major vascular procedures (aortic aneurysm repair, aorto-bifemoral bypass); general surgery; urology; gynaecology; liposuction; liver transplantation and duration of surgery. The non-surgical risk factors are multifactorial: advanced age, prolonged postoperative anaemia, positioning (supine v prone), alteration of venous drainage of the retina, hypertension, smoking, atherosclerosis, hyperlipidaemia, diabetes, hypercoagulability, hypotension, blood loss and large volume resuscitation. Other important cardiac causes are septic emboli from bacterial endocarditis and emboli caused by atrial myxomata. The majority of AION cases occur during CPB followed by head/neck surgery and prone spine surgery. CPB is used to allow coronary artery bypass grafting on a motionless heart. It has many side-effects and complications associated with its use and we report here a case of bilateral retinal infarction during routine coronary artery bypass grafting in a young male patient with multiple risk factors for developing this complication despite steps to minimise its occurrence.

[Management of bleeding disorders in intensive care medicine]

Bleeding disorders are frequent in intensive care medicine, the most common form being acquired. Trauma, gastrointestinal bleeding, liver failure, hematologic malignancies, and adverse drug reactions play an important role. Moderate to severe hereditary bleeding disorders are usually known prior to the acute disease state, while mild hereditary forms may manifest for the first time in association with the acute stress condition. Generally, proper history taking and structured observation are decisive in order to conduct an appropriate diagnostic workup and initiate logical hemostatic management. One cannot always wait for laboratory results during continuous blood loss or conditions such as hypothermia and acidosis. In such cases, pathophysiological extrapolation of expected hemostatic disturbances is essential for timely hemostatic management.

[The "Seville" Consensus Document on Alternatives to Allogenic Blood Transfusion. Sociedades españolas de Anestesiología (SEDAR), Medicina Intensiva (SEMICYUC), Hematología y Hemoterapia (AEHH), Transfusión sanguínea (SETS) Trombosis y Hemostasia (SETH)]

The Consensus Document on Alternatives to Allogenic Blood Transfusion (AABT) has been drawn up by a panel of experts from 5 scientific societies. The Spanish Societies of Anesthesiology (SEDAR), Critical Care Medicine and Coronary Units (SEMICYUC), Hematology and Hemotherapy (AEHH), Blood Transfusion (SETS) and Thrombosis and Hemostasis (SETH) have sponsored and participated in this Consensus Document. Alternatives to blood transfusion have been divided into pharmacological and non-pharmacological, with 4 modules and 12 topics. The main objective variable was the reduction of allogenic blood transfusions and/or the number of transfused patients. The extent to which this objective was achieved by each AABT was evaluated using the Delphi method, which classifies the grade of recommendation from A (supported by controlled studies) to E (non-controlled studies and expert opinion). The experts concluded that most of the indications for AABT were based on middle or low grades of recommendation, "C", "D", or "E", thus indicating the need for further controlled studies.

Impact of aprotinin and renal function on mortality: a retrospective single center analysis

BACKGROUND

An estimated up to 7% of high-risk cardiac surgery patients return to the operating room for bleeding. Aprotinin was used extensively as an antifibrinolytic agent in cardiac surgery patients for over 15 years and it showed efficacy in reducing bleeding. Aprotinin was removed from the market by the U.S. Food and Drug Administration after a large prospective, randomized clinical trial documented an increased mortality risk associated with the drug. Further debate arose when a meta-analysis of 211 randomized controlled trials showed no risk of renal failure or death associated with aprotinin. However, only patients with normal kidney function have been studied.

METHODS

In this study, we look at a single center clinical trial using patients with varying degrees of baseline kidney function to answer the question: Does aprotinin increase odds of death given varying levels of preoperative kidney dysfunction?

RESULTS

Based on our model, aprotinin use was associated with a 3.8-fold increase in odds of death one year later compared to no aprotinin use with p-value = 0.0018, regardless of level of preoperative kidney dysfunction after adjusting for other perioperative variables.

CONCLUSIONS

Lessons learned from our experience using aprotinin in the perioperative setting as an antifibrinolytic during open cardiac surgery should guide us in testing future antifibrinolytic drugs for not only efficacy of preventing bleeding, but for overall safety to the whole organism using long-term clinical outcome studies, including those with varying degree of baseline kidney function.

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, the need for transfusion, and the need for re-operation due to continued or recurrent bleeding. In the last few years questions have been raised regarding the comparative performance of the drugs. The safety of the most popular agent, aprotinin, has been challenged, and it was withdrawn from world markets in May 2008 because of concerns that it increased the risk of cardiovascular complications and death.

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 cell (RBC) transfusion, and adverse events, particularly vascular occlusion, renal dysfunction, and death.

SEARCH STRATEGY

We searched: the Cochrane Injuries Group's Specialised Register (July 2010), Cochrane Central Register of Controlled Trials (The Cochrane Library 2010, Issue 3), MEDLINE (Ovid SP) 1950 to July 2010, EMBASE (Ovid SP) 1980 to July 2010. 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 2010.

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. This version of the review includes a sensitivity analysis excluding trials authored by Prof. Joachim Boldt.

MAIN RESULTS

This review summarises data from 252 RCTs that recruited over 25,000 participants. Data from the head-to-head trials suggest an advantage of aprotinin over the lysine analogues TXA and EACA in terms of reducing perioperative blood loss, but the differences were small. Compared to control, aprotinin reduced the probability of requiring RBC transfusion by a relative 34% (relative risk [RR] 0.66, 95% confidence interval [CI] 0.60 to 0.72). The RR for RBC transfusion with TXA was 0.61 (95% CI 0.53 to 0.70) and was 0.81 (95% CI 0.67 to 0.99) 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 more effective in reducing the need for RBC transfusion (RR 0.90; 95% CI 0.81 to 0.99).Aprotinin reduced the need for re-operation due to bleeding by a relative 54% (RR 0.46, 95% CI 0.34 to 0.62). This translates into an absolute risk reduction of 2% and a number needed-to-treat (NNT) of 50 (95% CI 33 to 100). A similar trend was seen with EACA (RR 0.32, 95% CI 0.11 to 0.99) but not TXA (RR 0.80, 95% CI 0.55 to 1.17). The blood transfusion data were heterogeneous and funnel plots indicate that trials of aprotinin and the lysine analogues may be subject to publication bias.When compared with no treatment aprotinin did not increase the risk of myocardial infarction (RR 0.87, 95% CI 0.69 to 1.11), stroke (RR 0.82, 95% CI 0.44 to 1.52), renal dysfunction (RR 1.10, 95% CI 0.79 to 1.54) or overall mortality (RR 0.81, 95% CI 0.63 to 1.06). Similar trends were seen with the lysine analogues, but data were sparse. These data conflict with the results of recently published non-randomised studies, which found increased risk of cardiovascular complications and death with aprotinin. There are concerns about the adequacy of reporting of uncommon events in the small clinical trials included in this review.When aprotinin was compared directly with either, or both, of the two lysine analogues it resulted in a significant increase in the risk of death (RR 1.39, 95% CI 1.02, 1.89), and a non-significant increase in the risk of myocardial infarction (RR 1.11 95% CI 0.82, 1.50). Most of the data contributing to this added risk came from a single study - the BART trial (2008).

AUTHORS' CONCLUSIONS

Anti-fibrinolytic drugs provide worthwhile reductions in blood loss and the receipt of allogeneic red cell transfusion. Aprotinin appears to be slightly more effective than the lysine analogues in reducing blood loss and the receipt of blood transfusion. However, head to head comparisons show a lower risk of death with lysine analogues when compared with aprotinin. The lysine analogues are effective in reducing blood loss during and after surgery, and appear to be free of serious adverse effects.

Platelet-rich-plasmapheresis for minimising peri-operative allogeneic blood transfusion

BACKGROUND

Concerns regarding the safety of transfused blood have generated considerable enthusiasm for the use of technologies intended to reduce the use of allogeneic blood (blood from an unrelated donor). Platelet-rich plasmapheresis (PRP) offers an alternative approach to blood conservation.

OBJECTIVES

To examine the evidence for the efficacy of PRP in reducing peri-operative allogeneic red blood cell (RBC) transfusion, and the evidence for any effect on clinical outcomes such as mortality and re-operation rates.

SEARCH STRATEGY

We identified studies by searching MEDLINE (1950 to 2009), EMBASE (1980 to 2009), The Cochrane Library (Issue 1, 2009), the Internet (to March 2009) and the reference lists of published articles, reports, and reviews.

SELECTION CRITERIA

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

DATA COLLECTION AND ANALYSIS

Primary outcomes measured were: the number of patients exposed to allogeneic RBC transfusion, and the amount of RBC transfused. Other outcomes measured were: the number of patients exposed to allogeneic platelet transfusions, fresh frozen plasma, and cryoprecipitate, blood loss, re-operation for bleeding, post-operative complications (thrombosis), mortality, and length of hospital stay. Treatment effects were pooled using a random-effects model. Trial quality was assessed using criteria proposed by Schulz et al (Schulz 1995).

MAIN RESULTS

Twenty-two trials of PRP were identified that reported data for the number of patients exposed to allogeneic RBC transfusion. These trials evaluated a total of 1589 patients. The relative risk (RR) of exposure to allogeneic blood transfusion in those patients randomised to PRP was 0.73 (95%CI 0.59 to 0.90), equating to a relative risk reduction (RRR) of 27% and a risk difference (RD) of 19% (95%CI 10% to 29%). However, significant heterogeneity of treatment effect was observed (p < 0.00001; I² = 79%). When the four trials by Boldt are excluded, the RR is 0.76 (95% CI 0.62 to 0.93). On average, PRP did not significantly reduce the total volume of RBC transfused (weighted mean difference [WMD] -0.69, 95%CI -1.93 to 0.56 units). Trials provided inadequate data regarding the impact of PRP on morbidity, mortality, and hospital length of stay. Trials were generally small and of poor methodological quality.

AUTHORS' CONCLUSIONS

Although the results suggest that PRP is effective in reducing allogeneic RBC transfusion in adult patients undergoing elective surgery, there was considerable heterogeneity of treatment effects and the trials were of poor methodological quality. The available studies provided inadequate data for firm conclusions to be drawn regarding the impact of PRP on clinically important endpoints.

Antifibrinolytic therapy with tranexamic acid in pregnancy and postpartum

OBJECTIVE

The aim of this study is critically to review the available evidence regarding the use, efficacy and safety of tranexamic acid in the management of hemorrhage during pregnancy and for prevention and treatment of postpartum hemorrhage.

RESEARCH DESIGN AND METHODS

We performed a systematic search of electronic literature (PubMed, Embase, CINAHL, Scopus, Cochrane, DARE) to review all studies looking at the use of tranexamic acid during pregnancy and puerperium. We did a meta-analysis on three randomized controlled trials that evaluated reduction in blood loss in women undergoing cesarean sections with the use of tranexamic acid.

RESULTS

An electronic search yielded 34 articles, the studies dating from 1976 to 2010, five randomized controlled trials, seven observational studies, and twenty-two case reports. Meta-analysis showed that the estimate of the combined effect of tranexamic acid compared with placebo was a difference of 32.5 ml reduction in blood loss (95% CI -4.1-69.13; p = 0.08). Tranexamic acid was also used successfully to prevent and treat bleeding in observation studies and case reports. Pulmonary embolism was reported in two cases; however, the possible involvement of tranexamic acid in these thrombotic episodes could neither be confirmed nor excluded.

CONCLUSIONS

The clinical studies suggest that tranexamic acid reduces the amount of blood loss after delivery during cesarean sections and vaginal deliveries, and reduces the requirement for blood transfusion. Tranexamic acid seems to be safe and effective in the prevention and management of bleeding during pregnancy. Further investigation and larger clinical trials with better design and methodological quality are required to confirm these findings.

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, the need for transfusion, and the need for re-operation due to continued or recurrent bleeding. In the last few years questions have been raised regarding the comparative performance of the drugs. The safety of the most popular agent, aprotinin, has been challenged, and it was withdrawn from world markets in May 2008 because of concerns that it increased the risk of cardiovascular complications and death.

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 cell (RBC) transfusion, and adverse events, particularly vascular occlusion, renal dysfunction, and death.

SEARCH STRATEGY

We searched: the Cochrane Injuries Group's Specialised Register (July 2010), Cochrane Central Register of Controlled Trials (The Cochrane Library 2010, Issue 3), MEDLINE (Ovid SP) 1950 to July 2010, EMBASE (Ovid SP) 1980 to July 2010. 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 2010.

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 252 RCTs that recruited over 25,000 participants. Data from the head-to-head trials suggest an advantage of aprotinin over the lysine analogues TXA and EACA in terms of reducing perioperative blood loss, but the differences were small. Compared to control, aprotinin reduced the probability of requiring RBC transfusion by a relative 34% (relative risk [RR] 0.66, 95% confidence interval [CI] 0.60 to 0.72). The RR for RBC transfusion with TXA was 0.61 (95% CI 0.53 to 0.70) and was 0.81 (95% CI 0.67 to 0.99) 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 more effective in reducing the need for RBC transfusion (RR 0.90; 95% CI 0.81 to 0.99).Aprotinin reduced the need for re-operation due to bleeding by a relative 54% (RR 0.46, 95% CI 0.34 to 0.62). This translates into an absolute risk reduction of 2% and a number needed-to-treat (NNT) of 50 (95% CI 33 to 100). A similar trend was seen with EACA (RR 0.32, 95% CI 0.11 to 0.99) but not TXA (RR 0.80, 95% CI 0.55 to 1.17). The blood transfusion data were heterogeneous and funnel plots indicate that trials of aprotinin and the lysine analogues may be subject to publication bias.When compared with no treatment aprotinin did not increase the risk of myocardial infarction (RR 0.87, 95% CI 0.69 to 1.11), stroke (RR 0.82, 95% CI 0.44 to 1.52), renal dysfunction (RR 1.10, 95% CI 0.79 to 1.54) or overall mortality (RR 0.81, 95% CI 0.63 to 1.06). Similar trends were seen with the lysine analogues, but data were sparse. These data conflict with the results of recently published non-randomised studies, which found increased risk of cardiovascular complications and death with aprotinin. There are concerns about the adequacy of reporting of uncommon events in the small clinical trials included in this review.When aprotinin was compared directly with either, or both, of the two lysine analogues it resulted in a significant increase in the risk of death (RR 1.39, 95% CI 1.02, 1.89), and a non-significant increase in the risk of myocardial infarction (RR 1.11 95% CI 0.82, 1.50). Most of the data contributing to this added risk came from a single study - the BART trial (2008).

AUTHORS' CONCLUSIONS

Anti-fibrinolytic drugs provide worthwhile reductions in blood loss and the receipt of allogeneic red cell transfusion. Aprotinin appears to be slightly more effective than the lysine analogues in reducing blood loss and the receipt of blood transfusion. However, head to head comparisons show a lower risk of death with lysine analogues when compared with aprotinin. The lysine analogues are effective in reducing blood loss during and after surgery, and appear to be free of serious adverse effects.

Effects of tranexamic acid on blood loss during total hip arthroplasty

PURPOSE

To assess the effects of tranexamic acid (TA) in patients undergoing total hip arthroplasty (THA) for osteoarthritis.

METHODS

42 patients underwent primary THA for osteoarthritis by a single surgeon. 10 men and 11 women who did not receive TA were controls, whereas 9 men and 12 women who received TA constituted the treatment group. Both groups were matched for age, gender, body mass index, and American Society of Anesthesiologists grading. The type of prosthesis used (cemented or uncemented) was based on the surgeon's preference and patient age, activity level and demands. No hybrid prosthesis was used. 10 minutes prior to incision, a single dose of intravenous TA (10 mg per kg body weight) was given to patients in the treatment group. Comparison was made between both groups with regard to intra-operative blood loss, postoperative reduction in haemoglobin and haematocrit levels, blood transfusion, incidence of deep vein thrombosis, and the length of hospital stay.

RESULTS

The mean intra-operative blood loss (489 [SD, 281] vs. 339 [SD, 184] ml, p = 0.048) and the decrease in haemoglobin level (38 [SD, 12] vs. 29 [SD, 10] g/l, p=0.014) were significantly higher in the control than the treatment group. Two patients among the controls received a transfusion, compared to none in the TA group (p = 0.49, Fisher's exact test). The 2 patients who needed blood transfusion had blood losses of 600 and 690 ml, compared to a mean of 489 ml in the whole group. No patient in either group developed deep vein thrombosis or pulmonary embolism up to 3 months.

CONCLUSION

A single dose of intravenous TA (10 mg per kg body weight) given 10 minutes prior to THA is a cost-effective and safe means of minimising blood loss and reduction in haemoglobin concentrations as well as the need for allogenic blood transfusion, without increasing the risk of thromboembolic events.