Reinfusion of mediastinal blood after heart surgery

Cell salvage for minimising perioperative allogeneic blood transfusion in adults undergoing elective surgery

BACKGROUND

Concerns regarding the safety and availability of transfused donor blood have prompted research into a range of techniques to minimise allogeneic transfusion requirements. Cell salvage (CS) describes the recovery of blood from the surgical field, either during or after surgery, for reinfusion back to the patient.

OBJECTIVES

To examine the effectiveness of CS in minimising perioperative allogeneic red blood cell transfusion and on other clinical outcomes in adults undergoing elective or non-urgent surgery.

SEARCH METHODS

We searched CENTRAL, MEDLINE, Embase, three other databases and two clinical trials registers for randomised controlled trials (RCTs) and systematic reviews from 2009 (date of previous search) to 19 January 2023, without restrictions on language or publication status.

SELECTION CRITERIA

We included RCTs assessing the use of CS compared to no CS in adults (participants aged 18 or over, or using the study's definition of adult) undergoing elective (non-urgent) surgery only.

DATA COLLECTION AND ANALYSIS

We used standard methodological procedures expected by Cochrane.

MAIN RESULTS

We included 106 RCTs, incorporating data from 14,528 participants, reported in studies conducted in 24 countries. Results were published between 1978 and 2021. We analysed all data according to a single comparison: CS versus no CS. We separated analyses by type of surgery. The certainty of the evidence varied from very low certainty to high certainty. Reasons for downgrading the certainty included imprecision (small sample sizes below the optimal information size required to detect a difference, and wide confidence intervals), inconsistency (high statistical heterogeneity), and risk of bias (high risk from domains including sequence generation, blinding, and baseline imbalances). Aggregate analysis (all surgeries combined: primary outcome only) Very low-certainty evidence means we are uncertain if there is a reduction in the risk of allogeneic transfusion with CS (risk ratio (RR) 0.65, 95% confidence interval (CI) 0.59 to 0.72; 82 RCTs, 12,520 participants). Cancer: 2 RCTs (79 participants) Very low-certainty evidence means we are uncertain whether there is a difference for mortality, blood loss, infection, or deep vein thrombosis (DVT). There were no analysable data reported for the remaining outcomes. Cardiovascular (vascular): 6 RCTs (384 participants) Very low- to low-certainty evidence means we are uncertain whether there is a difference for most outcomes. No data were reported for major adverse cardiovascular events (MACE). Cardiovascular (no bypass): 6 RCTs (372 participants) Moderate-certainty evidence suggests there is probably a reduction in risk of allogeneic transfusion with CS (RR 0.82, 95% CI 0.69 to 0.97; 3 RCTs, 169 participants). Very low- to low-certainty evidence means we are uncertain whether there is a difference for volume transfused, blood loss, mortality, re-operation for bleeding, infection, wound complication, myocardial infarction (MI), stroke, and hospital length of stay (LOS). There were no analysable data reported for thrombosis, DVT, pulmonary embolism (PE), and MACE. Cardiovascular (with bypass): 29 RCTs (2936 participants) Low-certainty evidence suggests there may be a reduction in the risk of allogeneic transfusion with CS, and suggests there may be no difference in risk of infection and hospital LOS. Very low- to moderate-certainty evidence means we are uncertain whether there is a reduction in volume transfused because of CS, or if there is any difference for mortality, blood loss, re-operation for bleeding, wound complication, thrombosis, DVT, PE, MACE, and MI, and probably no difference in risk of stroke. Obstetrics: 1 RCT (1356 participants) High-certainty evidence shows there is no difference between groups for mean volume of allogeneic blood transfused (mean difference (MD) -0.02 units, 95% CI -0.08 to 0.04; 1 RCT, 1349 participants). Low-certainty evidence suggests there may be no difference for risk of allogeneic transfusion. There were no analysable data reported for the remaining outcomes. Orthopaedic (hip only): 17 RCTs (2055 participants) Very low-certainty evidence means we are uncertain if CS reduces the risk of allogeneic transfusion, and the volume transfused, or if there is any difference between groups for mortality, blood loss, re-operation for bleeding, infection, wound complication, prosthetic joint infection (PJI), thrombosis, DVT, PE, stroke, and hospital LOS. There were no analysable data reported for MACE and MI. Orthopaedic (knee only): 26 RCTs (2568 participants) Very low- to low-certainty evidence means we are uncertain if CS reduces the risk of allogeneic transfusion, and the volume transfused, and whether there is a difference for blood loss, re-operation for bleeding, infection, wound complication, PJI, DVT, PE, MI, MACE, stroke, and hospital LOS. There were no analysable data reported for mortality and thrombosis. Orthopaedic (spine only): 6 RCTs (404 participants) Moderate-certainty evidence suggests there is probably a reduction in the need for allogeneic transfusion with CS (RR 0.44, 95% CI 0.31 to 0.63; 3 RCTs, 194 participants). Very low- to moderate-certainty evidence suggests there may be no difference for volume transfused, blood loss, infection, wound complication, and PE. There were no analysable data reported for mortality, re-operation for bleeding, PJI, thrombosis, DVT, MACE, MI, stroke, and hospital LOS. Orthopaedic (mixed): 14 RCTs (4374 participants) Very low- to low-certainty evidence means we are uncertain if there is a reduction in the need for allogeneic transfusion with CS, or if there is any difference between groups for volume transfused, mortality, blood loss, infection, wound complication, PJI, thrombosis, DVT, MI, and hospital LOS. There were no analysable data reported for re-operation for bleeding, MACE, and stroke.

AUTHORS' CONCLUSIONS

In some types of elective surgery, cell salvage may reduce the need for and volume of allogeneic transfusion, alongside evidence of no difference in adverse events, when compared to no cell salvage. Further research is required to establish why other surgeries show no benefit from CS, through further analysis of the current evidence. More large RCTs in under-reported specialities are needed to expand the evidence base for exploring the impact of CS.

Cell Salvage at the ICU

Patient Blood Management (PBM) is a patient-centered, systemic and evidence-based approach. Its target is to manage and to preserve the patient's own blood. The aim of PBM is to improve patient safety. As indicated by several meta-analyses in a systematic literature search, the cell salvage technique is an efficient method to reduce the demand for allogeneic banked blood. Therefore, cell salvage is an important tool in PBM. Cell salvage is widely used in orthopedic-, trauma-, cardiac-, vascular and transplant surgery. Especially in cases of severe bleeding cell salvage adds significant value for blood supply. In cardiac and orthopedic surgery, the postoperative use for selected patients at the intensive care unit is feasible and can be implemented well in practice. Since the retransfusion of unwashed shed blood should be avoided due to multiple side effects and low quality, cell salvage can be used to reduce postoperative anemia with autologous blood of high quality. Implementing quality management, compliance with hygienic standards as well as training and education of staff, it is a cost-efficient method to reduce allogeneic blood transfusion. The following article will discuss the possibilities, legal aspects, implementation and costs of using cell salvage devices in an intensive care unit.

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.

Leukocyte removal efficiency of cell-washed and unwashed whole blood: an in vitro study

Leukocyte filtration of the cardiopulmonary bypass (CPB) perfusate after cardiac surgery has evolved as an important technique to prevent effector functions mediated by activated leukocytes. However, little is known about the filtration efficiency. Therefore, an in vitro study was conducted to define the leukocyte removal rate of a transfusion leukocyte-depletion filter, using cell-washed and unwashed whole porcine blood. In addition, the influence of different cell-washing protocols on the elimination rate of blood cells (leukocytes and platelets) was investigated.

Fresh, diluted, pooled, heparinized, porcine blood was processed using either a high-flow (HF, n-5) or quality-wash (QW, n-5) protocol on a continuous auto-transfusion system, or was left unprocessed (control n-5). Thereafter, all samples were filtered using a transfusion leukocyte-depletion filter. Blood samples for measurement of hematocrit, white blood cell count, including leukocyte differentiation and platelet count, were taken before and after filtration. To compare the experimental groups, the removal rate was presented as the fraction of leukocytes or platelets removed per plasma volume.

Cell washing significantly altered the fraction of leukocytes removed per plasma volume when compared to unprocessed blood (2.07 and 2.36 in the HF and QW groups, respectively, versus 1.34 in the control group, p-0.008 for both). No statistically significant difference in leukocyte removal rate was observed between the different cell-washing protocols. The leukocyte differential count showed that, during all experiments, the neutrophils were removed most efficiently (99.7%). Overall, significantly more platelets were depleted after cell washing compared to the control group (1.47 and 1.60 in the HF and QW groups, respectively, versus 1.12 in the control group, p-0.008 and 0.032, respectively). Furthermore, the amount of blood that could be filtered using a single pass technique did not significantly differ between the experimental groups. However, a larger variation in the total amount of filtered blood was observed in the unprocessed group (5709/398 mL) compared to the cell-washed groups (3609/42 and 4309/97 mL in the HF and QW groups, respectively).

In conclusion, blood processing with an auto-transfusion system significantly enhances the leukocyte and platelet removal efficiency of the transfusion leukocyte-depletion filter that was studied. In particular, neutrophils were efficiently removed.

Autotransfusion of a restricted volume of shed mediastinal blood does not affect the haemostatic capacity in patients following cardiac surgery

The aim was to investigate the haemostatic capacity after autotransfusion of shed mediastinal blood in patients following cardiac surgery. Fifteen cardiac surgery patients with a chest tube drainage ≥ 300 mL blood within the first 6 hours postoperatively were included. The haemostatic capacity was evaluated using whole blood thromboelastometry (ROTEM(®)), impedance aggregometry (Multiplate(®)) and conventional coagulation tests. Measurements were carried out in (1) mediastinal blood, and in blood samples obtained, (2) before autotransfusion, and (3) after autotransfusion of mediastinal blood. In shed mediastinal blood, ROTEM(®) analyses showed reduced clot firmness in the EXTEM (p < 0.001), INTEM (p < 0.001), and FIBTEM assay (p = 0.002). Platelet function and conventional coagulation parameters were significantly impaired (p < 0.001). However, ROTEM(®), platelet function and conventional coagulation tests remained unchanged after autotransfusion.

CONCLUSION

Shed mediastinal blood has a substantially reduced haemostatic capacity, but autotransfusion of an average of 350 mL did not affect the overall haemostatic capacity.

Time-related hemolysis in stored shed mediastinal blood after cardiopulmonary bypass

Reinfusion of mediastinal shed blood during cardiopulmonary bypass reportedly reduces the need for homologous blood transfusion. Although the fragility of blood components is thought to be amplified by shear stress during cardiopulmonary bypass and processing, the time-related deterioration of red blood cells (RBCs) in stored shed blood has not been studied extensively. In this study, we examined time-related hemolysis in shed blood stored at different temperatures. We examined processed shed blood collected from 15 patients (11 men and 4 women; mean age ± standard deviation, 71 ± 9 years) during cardiopulmonary bypass. The shed blood was collected and stored at 20°C (group A) or 4°C (group B). Stored blood collected by venipuncture at the end of the surgery was used as a control. Damage was assessed by measuring its free hemoglobin (Hb) levels, using a photometric assay. The free Hb levels in blood samples from each group were tested at 0, 3, 6, 12, 24, 36, and 48 h after surgery. The free Hb levels (g/dl) at 0, 12, and 24 h were 0.03 ± 0.01, 0.05 ± 0.02*, and 0.06 ± 0.02* in group A; 0.03 ± 0.02, 0.04 ± 0.03, and 0.05 ± 0.02* in group B; and 0.01 ± 0.01, 0.01 ± 0.01, and 0.01 ± 0.01 in the control group (*p < 0.05 vs. 0 h after surgery). The free Hb levels in stored shed blood significantly increased after 12 h in group A (20°C) and increased after 24 h in group B (4°C), whereas in drawn blood, they did not significantly increase over the first 24 h. Compared to storage at 20°C, storage at 4°C suppresses the increase in the free Hb levels.

Transfusion of shed mediastinal blood reduces the use of allogenic blood transfusion without increasing complications

BACKGROUND

Reduced use of allogenic blood components is a key issue in cardiac surgery. Several methods to conserve blood have been used; reinfusion of shed mediastinal blood (RSMB) has found widespread acceptance, but the efficacy and safety are still debated. The purpose of this study was to evaluate the effects of RSMB on the use of allogenic blood components and selected complications.

MATERIAL AND METHODS

Six hundred and twenty-three consecutive cardiac surgery patients in three successive periods, of whom patients in the middle period did not receive RSMB due to manufacturer delivery problems, were evaluated. Patients and procedures were characterized by EuroSCORE. Prospective collected data were: units of transfused allogenic blood, fresh frozen plasma (FFP) and platelets, postoperative blood loss and postoperative complications such as dialysis, re-operation due to bleeding, sternal infection and stroke. Length of stay in ICU was used as a general indicator of perioperative complications.

RESULTS

The number of patients receiving allogenic blood in periods with RSMB was significantly lower (36.5% versus 54.9%, p<0.005), while no difference was seen in FFP and platelets. The average number of transfused blood units was lower in patients receiving RSMB (2.07 versus 3.41, p=0.029), while FFP (1.34 versus 2.01, p=0.11) and platelets (0.58 versus 0.95, p=0.05) were not statistically significantly different. Postoperative bleeding was lower (759 versus 967 ml, p=0.032) in the periods with RSMB.

CONCLUSION

Patients receiving RSMB were less transfused with allogenic blood and had less postoperative drainage, while the frequency of observed postoperative complications was not different from patients who did not receive RSMB.

The future of blood management

An evolving understanding of the consequences of allogeneic blood transfusion and escalating costs of providing allogeneic blood have resulted in an interest in blood management. Understanding the consequences of allogeneic transfusion includes a recognition of the immunosuppressive effects of allogeneic transfusion, a growing awareness of transfusion-related acute lung injury, and a rediscovery of transfusion-associated circulatory overload. More recently, interest has focused on the effect of stored blood on patient outcome. Although this discussion is not all-inclusive, it is intended to show that many techniques can be applied to decrease the exposure to allogeneic blood.

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.

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.

Efficacy of cell saver in reducing homologous blood transfusions during OPCAB surgery: a prospective randomized trial

Despite the refinements in surgical technique, rates of homologous blood transfusion (HBT) in cardiac surgery remain high. The adverse effects of blood transfusion are well documented. Retransfusion of shed mediastinal blood reduces the requirement for HBTs during conventional coronary artery bypass grafting. However, some studies have found that autotransfusion leads to bleeding diathesis and paradoxical increase in blood transfusions. Through this prospective randomized trial, we have studied the safety and efficacy of this modality in patients undergoing off-pump coronary artery bypass grafting (OPCAB). Fifty patients enrolled in the study and 49 fulfilled the study criteria. They were randomly divided into group C (cell saver) and group N (non-cell saver). Whereas the cell saver group received processed shed autologous blood and homologous blood if necessary, the non-saver group was transfused homologous blood only. The threshold for transfusion was haemoglobin of 9 g dL(-1) in both the groups. The cell saver group required significantly less number of HBTs (1.6 +/- 1.2 vs. 2.4 +/- 1.3 units). The incidence of re-exploration was zero in both the groups. The mean mediastinal drainage in both the groups was not significantly different (355 +/- 196 vs. 316 +/- 119.8 mL). The number of patients requiring any blood transfusion however was very high. All the patients in the non-saver group and 20 (83%) of the patients in the saver group received homologous blood. During OPCAB surgery, the use of cell saver reduced the requirement for HBT. Its use is not associated with any clinically significant bleeding diathesis.

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.

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.

Clinical efficacy of postoperative autologous transfusion of filtered shed blood in hip and knee arthroplasty

BACKGROUND

Total knee arthroplasty (TKA) or total hip arthroplasty (THA) regularly results in postoperative requirement of blood transfusion. Because of the disadvantages of allogeneic blood transfusion (ABT) such as the risk of transfusion-associated infections, incompatibility-related transfusion fatalities, or immunomodulatory effects, a continuing effort to reduce allogeneic blood transfusion is important. For this purpose, the effect of reinfusion of drain blood, via a postoperative wound drainage and reinfusion system, on the need for allogeneic blood transfusion was evaluated.

STUDY DESIGN AND METHODS

Using a prospective observational quality assessment design, we compared 135 patients scheduled for TKA or THA with a historic group of 96 patients. In the study group the Bellovac ABT autotransfusion system was used. The shed blood was returned either when 500 mL were collected or at most 6 hours after surgery. Compared were the preoperative, postoperative, and discharge hemoglobin, as well as the number of allogeneic blood transfusions.

RESULTS

There were no statistical differences between preoperative, postoperative, and discharge hemoglobin levels. Autologous transfusion reduced the number of patients receiving ABT overall from 35 percent (control) to 22 percent (study). The decrease of allogeneic transfusion requirement was most significant after TKA: from 18 percent to 6 percent (p < 0.001).

CONCLUSION

We conclude that the Bellovac ABT device reduces allogeneic blood transfusions in TKA and THA.

Safety and efficacy of perioperative cell salvage and autotransfusion after coronary artery bypass grafting: a randomized trial

BACKGROUND

The aim of this study was to ascertain whether cell salvage and autotransfusion after first time elective coronary artery bypass grafting is associated with a significant reduction in the use of homologous blood, a clinically significant derangement of postoperative clotting profiles, or an increased risk of postoperative bleeding.

METHODS

Patients were randomized to autotransfusion (n = 98) receiving autotransfused washed blood from intraoperative cell salvage and postoperative mediastinal fluid cell salvage after coronary artery bypass surgery or control (n = 102) receiving stored homologous blood only after coronary artery bypass surgery.

RESULTS

There was no statistical difference between the groups in terms of demographics, comorbidity, risk stratification, or operative details. Mean volume of blood autotransfused was 367 +/- 113 mL. Patients in the autotransfusion group were significantly less likely to receive a homologous blood transfusion compared with controls (odds ratio 0.40, 95% confidence interval [CI] 0.22-0.71) and received significantly fewer units of blood per patient compared with controls (0.43 +/- 1.5 vs 0.90 +/- 2.0 U, p = 0.02). There was no difference between the groups in terms of postoperative blood loss, fluid requirements, blood product requirements, or in the incidence of adverse clinical events (p = NS chi(2)). Autotransfusion did not produce any significant derangement of thromboelastograph values or laboratory measures of clotting pathway function (prothrombin time, activated partial thromboplastin time, fibrinogen, and fibrinogen D-dimer levels) when compared with the effect of homologous blood transfusion (p = NS, repeated measures analysis of variance [MANOVA]).

CONCLUSIONS

Autotransfusion is a safe and effective method of reducing the use of homologous bank blood after routine first time coronary artery bypass grafting.

Heparin versus danaparoid in off-pump coronary bypass grafting: results of a prospective randomized clinical trial

OBJECTIVE

The incidence of heparin-induced thrombocytopenia is increasing, and the thrombin inhibitor danaparoid could be a useful alternative. The objective of the present study was to compare danaparoid and heparin in patients undergoing off-pump coronary artery bypass grafting.

METHODS

In a prospective, randomized, double-blind clinical trial comparing heparin (bolus of 1 mg/kg) with danaparoid (bolus of 40 U/kg), 71 patients underwent off-pump coronary artery bypass grafting with one of the study drugs. The amount of blood lost, the number of homologous blood products transfused, the troponin T levels, and the amount of anti-Xa activity were monitored.

RESULTS

Thirty-four patients underwent 2.6 +/- 0.7 bypasses with danaparoid, and 37 patients underwent 2.5 +/- 0.9 grafts with heparin (P =.8). Postoperative blood losses averaged 1394 +/- 1033 mL in patients receiving danaparoid and 1130 +/- 868 mL in patients receiving heparin (P =.2). The number of homologous blood products transfused averaged 3.6 +/- 7 units in patients receiving danaparoid and 1.9 +/- 4.4 units in patients receiving heparin (P =.2). The number of patients requiring homologous blood transfusion was higher in patients receiving danaparoid (18/34 [53%]) than in patients receiving heparin (10/37 [27%], P =.03). Serum anti-Xa activity averaged 1.6 +/- 0.6 U/mL in patients receiving danaparoid and 1.9 +/- 0.8 U/mL in patients receiving heparin 30 minutes after injection of the drugs (P =.1) and 0.3 +/- 0.1 and 0.04 +/- 0.08 U/mL, respectively, 12 hours after coronary artery bypass grafting (P =.001). Troponin serum levels were similar 48 hours after coronary artery bypass grafting (0.5 +/- 0.6 and 0.4 +/- 0.6 microg/L, respectively).

CONCLUSION

Although off-pump coronary artery bypass grafting with danaparoid versus heparin increases the number of patients exposed to homologous blood transfusion (relative risk, 2; 95% confidence limits, 1-4), off-pump coronary artery bypass grafting with danaparoid is a valuable alternative to heparin in patients with thrombocytopenia requiring surgical intervention.

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

Articles were identified by: computer searches of MEDLINE, EMBASE, Current Contents (to July 2002), the Cochrane Controlled Trials Register (Issue 2, 2002) and websites of international health technology assessment agencies. References in the identified trials and review articles were searched and authors contacted to identify additional studies.

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

Trial quality was assessed using criteria proposed by Schulz et al. (Schulz 1995) and Jadad et al. (Jadad 1996). Main outcomes measured 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 40% (relative risk [RR] = 0.60: 95% confidence interval [CI] = 0.51 to 0.70). The absolute reduction in risk (ARR) of receiving an allogeneic RBC transfusion was 23% (95%CI = 16% to 30%). In orthopaedic procedures the relative risk (RR) of exposure to RBC transfusion was 0.42 (95%CI = 0.32 to 0.54) compared to 0.78 (95%CI = 0.68 to 0.88) for cardiac procedures. The use of cell salvage resulted in an average saving of 0.64 units of allogeneic RBC per patient (weighted mean difference [WMD] = -0.64: 95%CI = -0.86 to -0.46). Cell salvage did not appear to impact adversely on clinical outcomes.

REVIEWER'S 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 patient's treatment status biasing the results in favour of cell salvage.