Adverse effects of postoperative infusion of shed mediastinal blood

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.

Sodium citrate effectively used in shed mediastinal blood autotransfusion after cardiac surgery

BACKGROUND

We used sodium citrate as an alternative anticoagulation agent to heparin in the procedure of autologous blood transfusion with patients with postoperative haemorrhage after CPB. The aim of study was to evaluate the efficacy and safety of sodium citrate used in shed mediastinal blood autotransfusion after cardiac surgery.

METHODS

Ninety-three patients were divided into two groups in this study. In the control group, 52 patients' shed mediastinal blood was discarded. The reinfusion group consisted of 41 patients receiving a reinfusion of washed autologous red cells from shed mediastinal blood. Each 400 mL shed blood sample was anticoagulated by 140 mL of 1.6% diluted sodium citrate in the washing procedure using a blood recovery machine. Hemoglobin (Hb), hematocrit (Hct), and electrolyte concentrations in both the patients and shed mediastinal blood were measured before and after this procedure.

RESULTS

The mean volume of autotransfused shed blood was 239.5 ± 54.6 mL.The Hct of the washed red cells was 56.8 ± 6.1%. Significantly, fewer units of allogeneic blood were required per patient in the reinfusion group at 24 h postoperatively (2.91 ± 1.34 vs 4.03 ± 0.19 U, p = 0.002). At 24 h postoperatively, Hb and Hct levels were higher in the reinfusion group than in the control group. The calcium ion concentration was very low in the shed mediastinal blood, 0.25 ± 0.08 mmol/L, and was lower after washing, 0.15 ± 0.04 mmol/L.

CONCLUSIONS

Sodium citrate, as an alternative anticoagulant agent, can be used in autologous shed mediastinal blood transfusion after CPB cardiac surgery. This procedure can effectively reduce the amount of allogeneic blood for patients with haemorrhage.

Additional postoperative cell salvage of shed mediastinal blood in cardiac surgery does not reduce allogeneic blood transfusions: a cohort study

Objectives:

Does additional postoperative collection and processing of mediastinal shed blood with a cell salvage device reduce the number of allogeneic blood transfusions compared to intraoperative cell salvage alone?

Methods:

A single-centre cohort study in which adult patients with coronary artery bypass grafting or aortic valve replacement were allocated to either a C.A.T.S® group with intraoperative blood processing only or a CardioPat® group with both intra- and postoperative blood processing. The primary endpoint was the number of allogeneic blood transfusions during hospital admission.

Results:

The study included 99 patients; 50 in the C.A.T.S® and 49 in the CardioPat® group. There was no difference in the number of red blood cells (RBC) (C.A.T.S® group 43 units versus CardioPat® 50 units, p=0.74), fresh frozen plasma (C.A.T.S® 8 units versus CardioPat® 8 units, p=1.00) or platelets (C.A.T.S® 5 units versus CardioPat® 4 units, p=1.00) transfused during the hospital stay. Cardiac creatinine kinase (CK-MB) and troponin levels did not differ between the groups although a significant time effect (p<0.001) was present. Creatinine kinase (CK) levels were not different between the groups three hours after arrival in the intensive care unit (ICU) (CardioPat® group versus C.A.T.S® group, p=0.17). But, compared to the C.A.T.S® group on the first (350 [232-469] IU/L) and second postoperative days (325 [201-480] IU/L), the increase in CK levels was more in the CardioPat® group on the first (431 [286-642] IU/L, p=0.02) and second postoperative days (406 [239-760] IU/L, p=0.05), resulting in a difference between the groups (p=0.04)

Conclusions:

Postoperative cell salvage does not reduce transfusion requirements compared to intraoperative cell salvage alone, but results in elevated total CK levels that suggest haemolysis.

Dynamic changes in clot formation determined using thromboelastometry after reinfusion of unwashed anticoagulated cell-salvaged whole blood in total hip arthroplasty

BACKGROUND

Cell salvage is a key part of patient blood management. Different techniques are available for salvaging blood. A new intra-operative autotransfusion filter system became available for reinfusion of unwashed whole blood. Concern exists regarding whether this technique induces coagulation disturbances, offsetting the benefits of the reinfusion of autologous blood. This study was designed to investigate the content of intra-operatively salvaged filtered blood and its impact after reinfusion on clot formation in patients undergoing primary hip arthroplasty.

MATERIALS AND METHODS

Twenty-five patients scheduled for primary total hip arthroplasty were enrolled in the study. Cell salvage was performed using a new intra-operative autotransfusion filter system. Before surgery and within 1 hour of reinfusion of 300 mL or more of salvaged whole blood, blood samples were taken to assess clot formation by thromboelastometry and standard laboratory-based coagulation profiling. Cytokine content of the salvaged blood was assessed by enzyme-linked immunosorbent assays.

RESULTS

Following reinfusion of 460 mL (median) of salvaged blood, thromboelastometry showed normal clot formation and did not indicate a coagulopathy. Clotting time, clot formation time, maximum firmness and maximum lysis all remained within the normal range. Standard laboratory coagulation tests were also normal in all patients before surgery and after reinfusion. Although monocyte chemoattractant protein-1 levels were higher than normal, all other measured cytokines were either undetectable or within the normal range. No adverse events were seen following cell salvage.

DISCUSSION

Reinfusion of unwashed salvaged whole blood did not alter clot formation in our patients. The results add to the knowledge about this approach and contribute to the growing body of evidence regarding the lack of adverse events when reinfusing unwashed shed blood in major orthopaedic procedures.

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.

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.

Postoperative Care of the Cardiac Surgical Patient

The subspecialty of interventional cardiology began in 1977. Since then, the discipline of interventional cardiology has matured rapidly, particularly with regards to ischemic heart disease. As a result, more patients are undergoing percutaneous catheter interventional therapy for ischemic heart disease and fewer patients are undergoing surgical myocardial revascularization. Those patients referred for surgical revascularization are generally older and have more complex problems. Furthermore, as the population ages more patients are referred to surgery for valvular heart disease. The result of these changes is a population of surgical patients older and sicker than previously treated.

Influence of early re-infusion of autologous shed mediastinal blood on clinical outcome after cardiac surgery

Various strategies have been proposed to decrease allogeneic blood transfusion requirements after cardiac surgery. The aim of the study was to evaluate the efficacy of collected and re-infused autologous shed mediastinal blood on a patient's postoperative course. Ninety patients who underwent heart surgery with cardiopulmonary bypass (CPB) were studied. The patients were divided into two groups: Group 1 (n=41) received the centrifuged autologous shed mediastinal blood collected from the cardiotomy reservoir 4 hours after surgery; in Group 2 (n=49) all shed mediastinal blood was discarded (control group). Haemoglobin (Hb), haematocrit (Hct), C-reactive protein values, and leucocyte count were compared before surgery, at 4 h and 20 h after surgery, and on the fifth postoperative day. We have measured serum procalcitonin (PCT) concentration at 4 h and 20 h after CPB. We assessed drained blood loss within 20 postoperative hours. Leucocyte count, Hb, Hct values, C-reactive protein, and procalcitonin concentration did not differ between the groups before and at 4 h after surgery. Hb, Hct level, and leucocyte count were similar at 20 hours and on the fifth day after surgery. At 20 hours after surgery, an increase of serum PCT concentration (>0.5-2 ng/mL) was more frequent in Group 2 (58.3% vs. 33.3%; p = 0.03). On the fifth postoperative day, C-reactive protein concentration was lower in Group 1 (71.74 +/- 15.23; p <0.01) compared to Group 2 (93.53 +/- 20.3). Postoperative blood loss did not differ between the groups. Requirement for allogeneic blood transfusion was significantly lower in Group 1 (14.6% vs. 38.8%; p < 0.02). Patients in Group 1 developed less infective complications compared with Group 2 (2.4% and 16.3%, respectively; p < 0.05). The length of postoperative in-hospital stay was shorter in Group 1 compared with Group 2 (9.32 +/- 2.55 and 16.45 +/- 6.5, respectively; p < 0.05). We conclude that postoperative re-infusion of autologous red blood cells processed from shed mediastinal blood did not increase bleeding tendency and systemic inflammatory response and was effective in reducing the requirement for allogeneic transfusion, the rate of infective complications and the length of postoperative in-hospital stay.

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.

Postoperative treatment with low molecular weight heparin after right heart assist for coronary artery bypass grafting

Right heart assist (RHA) was used for coronary artery bypass grafting (CABG). We explored the affection of the coagulation system during surgery and evaluated two different antithrombotic treatments postoperatively. The pilot study comprised 14 patients. During surgery activated clotting time (ACT) was kept > 200 sec. By random the patients were selected to different postoperative treatments. The control group received acetyl salicylic acid (ASA) 150 mg daily, the intervention group received ASA 150 mg daily and Low Molecular Weight Heparin (LMWH) 5000 IU x2 for three days. Serum levels of prothrombin fragment 1 and 2 (F 1 + 2), plasmin-antiplasmin product (PAP), anti-Xa activity and functional antithrombin (ATIII) were measured. During surgery there was no increase of F 1 + 2 or PAP. After protamin was administered there was a significant increase of F 1 + 2 but not in PAP during the next 6 hours. Postoperative antithrombotic treatment with LMWH seems to normalise F1 + 2 while ASA does not. ACT level > 200 sec. seems sufficient for RHA-CABG surgery. Fibrinolytic agents are not necessary. It seems that postoperative LMWH treatment prevents increased thrombin formation. General recommendations with respect to antithrombotic treatment beyond ASA can not be made based on study.

Composition of the blood sampled from surgical drainage after joint arthroplasty: quality of return

BACKGROUND

The quality of blood obtained with a device for postoperative blood drainage and autotransfusion (Bellovac-ABT, Astra Tech AB) was investigated in 50 patients who underwent total hip replacement (THR) or total knee replacement (TKR) surgeries.

STUDY DESIGN AND METHODS

The Bellovac-ABT drainage set was inserted and blood collection began after skin closure (THR) or 15 minutes after tourniquet deflation (TKR). A collecting bag stayed in place for less than 6 hours. The product was then returned after sedimentation and discard of supernatant, without anticoagulants.

RESULTS

Blood returned with the Bellovac-ABT had optimal hemoglobin levels and red blood cell (RBC) counts; the low platelet count reduced the risk of disseminated intravascular coagulation. Inertia of materials maintained acceptable values of C-reactive protein, whereas cytokines and complement split products rose rapidly. Higher concentrations of adenosine triphosphate and 2,3-diphosphoglycerate than in circulating blood suggested a normal RBC metabolism. No adverse reactions were observed in any participants.

CONCLUSION

Because of its simplicity and safety, the Bellovac-ABT autologous blood transfusion system is recommended in THR or TKR without joint infection or malignancy.

Modeling Centrifugal Cell Washers Using Computational Fluid Dynamics

Reinfusion of shed blood during surgery could avoid the need for blood transfusions. Prior to reinfusion of the red blood cells, the shed blood must be washed in order to remove leukocytes, platelets, and other contaminants. Further, the hematocrit of the washed blood must be increased. The feasibility of using computational fluid dynamics (CFD) to guide the design of better centrifuges for processing shed blood is explored here. The velocity field within a centrifuge bowl and the rate of protein removal from the shed blood has been studied. The results obtained indicate that CFD could help screen preliminary centrifuge bowl designs, thus reducing the number of initial experimental tests required when developing new centrifuge bowls. Although the focus of this work is on washing shed blood, the methods developed here are applicable to the design of centrifuge bowls for other blood-processing applications.

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.

Autotransfusion of Shed Mediastinal Blood *

RATIONALE

After the introduction of autotransfusion of shed mediastinal blood following cardiac surgery, the incidence of mediastinitis increased. The role of autotransfusion in the increased occurrence of this serious complication was examined.

METHODS

Using a case-control design, the preoperative, intraoperative, and postoperative characteristics of 11 patients with mediastinitis were compared to those of 33 randomly selected patients undergoing cardiac surgery between September 1, 2000, and April 15, 2001 (control subjects).

RESULTS

Patients with mediastinitis were significantly more likely to have a body mass index > 30 (unadjusted odds ratio [OR], 9.9; 95% confidence interval [CI], 2.3 to 42.5), to have received antibiotic therapy during the 2 weeks prior to cardiac surgery (OR, 12.0; 95% CI, 1.1 to 131), or to have required re-exploration within 24 h of the original operation (OR, 8.3; 95% CI, 1.8 to 39). Patients with mediastinitis had 3.4 known risk factors for mediastinitis, compared to only 1.4 risk factors per control subject (p = 0.0001), and longer duration of autotransfusion. After adjustment for other risk factors, autotransfusion for > 6 h was significantly associated with the development of mediastinitis (adjusted OR, 11.9; 95% CI, 1.4 to 97.2).

CONCLUSION

Retransfusion of shed mediastinal blood for > 6 h after cardiac surgery was an independent risk factor for mediastinitis.

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.

Safety and efficacy of methods for reducing perioperative allogeneic transfusion: a critical review of the literature

A number of pharmacologic and nonpharmacologic technologies are in current use to minimize perioperative homologous blood use. Clinical trials, many of them randomized controlled trials, have been done evaluating these approaches and have demonstrated their efficacy. However, data on safety has relied mostly on case reports, uncontrolled studies, and, for the pharmacologic agents, extrapolation from the nonsurgical setting. In this review I analyze the data from the randomized trials and the lower-level evidence studies to provide the best estimates in safety with these alternatives. In general, these alternatives are safe with proper dosing and monitoring of effects. With aprotinin, the primary concern is anaphylaxis, and this predominantly with re-exposure. With aprotinin and with the anti-fibrinolytics, increased venous thromboembolic risk has not been a consistent finding. Tranexamic acid use intraoperatively is advantageous, but postoperative use appears to have no advantage and may be associated with renal dysfunction. DDAVP is low-risk, provided it is not overused, which can induce hyponatremia. Autologous predonation probably has similar risks as homologous blood with respect to transfusion errors and bacterial infection. As with most medical interventions, we must be vigilant to prevent human error.

Coagulation, fibrinolysis, and cell activation in patients and shed mediastinal blood during coronary artery bypass grafting with a new heparin-coated surface

OBJECTIVES

Heparin coating of the cardiopulmonary bypass circuit is shown to improve the biocompatibility of the surface. We have studied a new heparin surface, the Corline Heparin Surface, applied to a complete set of an extracorporeal device used during coronary artery bypass grafting in terms of activation of inflammation, coagulation, and fibrinolysis in patients and in shed mediastinal blood.

METHODS

Sixty patients scheduled for coronary artery bypass grafting were randomized to one of 3 groups with heparin-coated devices receiving either a standard, high, or low dose of systemic heparin or to an uncoated but otherwise identical circuit receiving a standard dose of systemic heparin. Samples were drawn before, during, and after the operation from the pericardial cavity and in shed mediastinal blood. No autotransfusion of shed mediastinal blood was performed.

RESULTS

The Corline Heparin Surface significantly reduced the activation of coagulation, fibrinolysis, platelets, and inflammation compared with that seen with the uncoated surface in combination with a standard dose of systemic heparin during cardiac surgery with cardiopulmonary bypass. Both a decrease and an increase of systemic heparin in combination with the coated heparin surface resulted in higher activation of these processes. A significantly higher expression of all studied parameters was found in the shed mediastinal blood compared with in systemic blood at the same time.

CONCLUSIONS

The Corline Heparin Surface used in cardiopulmonary bypass proved to be more biocompatible than an uncoated surface when using a standard systemic heparin dose. The low dose of systemic heparin might not be sufficient to maintain the antithrombotic activity, and the high dose resulted in direct cell activation rather than a further anti-inflammatory and anticoagulatory effect.

Globin attenuates the innate immune response to endotoxin

Hemoglobin is an endotoxin (lipopolysaccharide; LPS)-binding protein that synergistically increases the release of proinflammatory cytokines from the innate immune system in response to LPS. It has been suggested that this activity of hemoglobin facilitates the recognition of Gram-negative bacteria in a wound, thereby maximizing immune efficiency. This synergy may be important to the pathogenesis of a broad spectrum of clinical conditions because elevated hemoglobin levels frequently are observed in patients after the transfusion of red cells, trauma, cardiopulmonary bypass surgery, hemolysis, in addition to other disorders. To determine the molecular basis of the specific hemoglobin-LPS synergy, in this article we tested the effects of globin itself on macrophage responses to LPS. Paradoxically, these studies revealed that globin suppressed tumor necrosis factor (TNF) synthesis in LPS-stimulated murine and human macrophage cultures. LPS comigrated with globin on non-denaturing electrophoretic gels, giving direct evidence for binding. Globin specifically inhibited LPS activity in the standard Limulus assay but did not inhibit interleukin-1beta-mediated TNF synthesis. Iron supplementation of macrophage cultures significantly increased interleukin-1beta-induced TNF release. Intraperitoneal administration of globin protected mice against both LPS-induced lethality and experimentally induced bacterial infection. Thus, the heme-iron moiety of hemoglobin, and not the binding of LPS to globin, enhanced macrophage responses to LPS.

Hemostatic Abnormalities in Cardiopulmonary Bypass: Pathophysiologic and Transfusion Considerations

Cardiac surgical procedures typically use cardiopulmo nary bypass (CPB), a technique that diverts blood from the heart and lungs, where it is oxygenated and pumped back into the circulation. CPB is associated with significant pathophysiologic changes leading to an increased bleeding risk. Bleeding during CPB occurs for multiple reasons; the primary reason is the expo sure of blood to the material components of the CPB system, with intense systemic coagulation and platelet, fibrinolytic, and endothelial activation. To counteract the coagulation activation, extremely high levels of heparin anticoagulation are required to prevent sys temic thrombosis. Thrombin generation through tissue factor pathway activation is now thought to be the predominant mechanism of coagulation activation in CPB. The stimulus for tissue factor exposure to blood is thought to be a systemic activation of tissue factor on monocytes and endothelial cells caused by comple ment activation by the CPB materials and circulating inflammatory mediators. Despite improvements in the CPB system, surgical techniques, and blood conserva tion methods, the demand for blood in such procedures remains sustantial. Optimal blood use can be achieved by combining blood conservation measures with the transfusion of blood components according to strict guidelines. Blood is a limited resource and must be used wisely and cautiously. The risks and costs associ ated with transfusion are compelling reasons to mini mize unnecessary exposure to blood. However, the bene fits of transfusion are well established, and the risks are reasonably low. New developments in the surfaces of the CPB system, use of established and new protease inhibitors, and new blood conservation measures offer promise in decreasing the bleeding risk associated with CPB.

Reinfusion of mediastinal blood after heart surgery

BACKGROUND

Several authors studying autotransfusion of shed mediastinal blood in patients undergoing heart operations have published conflicting results regarding reduction of the need for homologous blood transfusion. The effect on coagulation parameters is also unclear.

METHODS

In a prospective randomized study, 198 patients who underwent coronary artery bypass grafting or a valvular operation were divided into 2 groups: a group with autotransfusion of shed mediastinal blood after an operation and a control group. Continuous reinfusion of mediastinal blood was done until no drainage was present or for a period of 12 hours after the operation. The amount of blood lost and autotransfused, the number of homologous blood products transfused, and the coagulation parameters were monitored.

RESULTS

The number of patients requiring homologous blood transfusion was significantly different between the 2 groups (54/98 [55%] in autotransfused patients vs 73/100 [73%] in the control group, P =.01). The number of re-explorations for excessive bleeding was similar in the 2 groups (7/98 [7.1%] vs 8/100 [8%]), but the amount of blood collected postoperatively was higher in the autotransfused patients compared with control patients (1200 +/- 201 mL vs 758 +/- 152 mL, P =.0007). Coagulation parameters analyzed and complication rates were similar in the 2 groups after the operations.

CONCLUSION

Autotransfusion of shed mediastinal blood reduces the need for homologous blood transfusion in patients undergoing various cardiac operations. The cause of increased shed blood in patients undergoing autotransfusion remains unclear.

Safety and efficacy of shed mediastinal blood transfusion after cardiac surgery: a multicenter observational study. Multicenter Study of Perioperative Ischemia Research Group

OBJECTIVE

To examine the efficacy and safety of shed mediastinal blood (SMB) transfusion in preventing allogenic red blood cell (RBC) transfusion.

DESIGN

An observational clinical study.

SETTING

Twelve US academic medical centers.

PARTICIPANTS

Six hundred seventeen patients undergoing elective primary coronary artery bypass grafting.

INTERVENTIONS

Patients were administered SMB transfusion or not, according to institutional and individual practice, without random assignment.

MEASUREMENTS AND RESULTS

The independent effect of SMB transfusion on postoperative RBC transfusion was examined by multivariable modeling. Potential complications of SMB transfusion, such as bleeding and infection, were examined. Three hundred twelve of the study patients (51%) received postoperative SMB transfusion (mean volume, 554 +/- 359 mL). Patients transfused with SMB had significantly lower volumes of RBC transfusion than those not receiving SMB (0.86 +/- 1.50 v 1.08 +/- 1.65 units; p < 0.05). However, multivariable analysis showed that SMB transfusion was not predictive of postoperative RBC transfusion. Demographic factors (older age, female sex), institution, and postoperative events (greater chest tube drainage, lower hemoglobin level on arrival to the intensive care unit, and use of inotropes) were significant predictors of RBC transfusion. The volume of chest tube drainage on the operative day (707 +/- 392 v 673 +/- 460 mL; p = 0.30), reoperation for hemorrhage (3.1% v2.5%; p = 0.68), and overall frequency of infection (5.8% v 6.6%; p = 0.81) were similar between patients receiving and not receiving SMB, respectively. However, in patients who did not receive allogenic RBC transfusion, there was a significantly greater frequency of wound infection in the SMB group (3.6% v0%; p = 0.02).

CONCLUSION

These data suggest that SMB is ineffective as a blood conservation method and may be associated with a greater frequency of wound infection.

Left internal mammary artery graft perforation due to high-pressure stent deployment

Perforation of newly placed left internal mammary artery (LIMA) grafts due to stent deployment is an infrequent but potentially dangerous complication of coronary interventions. It may lead to brisk hemorrhage and massive cardiac tamponade requiring emergent pericardiocentesis and surgery. We report a case of a LIMA graft perforation following stent deployment with a high-pressure balloon 12 days after surgery. The patient was treated with emergent pericardiocentesis, rapid autotransfusion of the pericardial aspirate into the systemic circulation, and surgical repair of the ruptured vessel.

[Blood conservation effect and safety of shed mediastinal blood autotransfusion after cardiac surgery]

Autotransfusion of shed mediastinal blood after cardiac surgery has been used to reduce risks related to homologous blood transfusions. To document the efficacy and safety of autotransfusion, we compared clinical findings of 80 patients receiving shed mediastinal blood (autotransfusion group) with those of the control group of 52 patients. The amount of the autotransfusion was limited to 800 ml, given the potentially harmful effects of shed blood transfusion. The mean transfused shed volume was 314 +/- 236 ml (S.D.). The serum levels of FDP-E, D-dimer and TAT after autotransfusion were higher in the autotransfusion group than in the control group (p = 0.01, p = 0.0004, p = 0.001, respectively). However, postoperative blood loss and the rate of reexploration for bleeding were similar in the two groups. The patients receiving blood products were fewer in the autotransfusion group than those in the control group (21% vs 44%; p = 0.005). Autotransfusion did not increase postoperative complications, including infection. Thus, although autotransfusion of mediastinal shed blood has the potential to affect hemostasis, unless the amount of autotransfusion exceeds 800 ml, it appears that this method is clinically safe and effective as a mean of blood conservation.

Acute normovolemic red cell exchange for cardiopulmonary bypass in sickle cell disease

A patient with sickle cell disease (hematocrit, 28.5%; hemoglobin S fraction, 79%), required mitral valve repair. Partial red cell removal and blood component sequestration with an autotransfusion device before cardiopulmonary bypass initially decreased the sickle red cell mass. This was followed by an acute one-volume whole blood exchange transfusion performed upon the initiation of cardiopulmonary bypass, resulting in a further reduction. Both techniques yielded fresh autologous plasma for use; sequestration yielded a platelet-pheresis product. Adequate postbypass hemostasis was demonstrated.

Biocompatibility in cardiopulmonary bypass

Recent advances in surgical techniques and perfusion technology allow cardiac operations to be performed routinely with low mortality rates. However, patients undergoing cardiac operations with cardiopulmonary bypass (CPB) are still associated with bleeding disorders, thrombotic complications, massive fluid shifts, and the activation of blood components that are collectively known as the whole body inflammatory response. In this review, the effect of cardiopulmonary bypass on various humoral and cellular components of blood is examined. Blood activation caused by interaction with artificial materials of extracorporeal circuit and by material-independent stimuli is discussed. Methods to control blood activation during and after cardiopulmonary bypass are described. These include surface modification of extracorporeal circuit, control of flow dynamics in the circuit, pharmacological intervention, and the use of extracorporeal devices to remove inflammatory mediators. Recent findings on the effects of heparin-coated circuits on inflammatory response and clinical outcome are reviewed. It appears that the causes of inflammatory response to cardiopulmonary bypass are multifactorial and that an integrated strategy is needed to control and eliminate the negative effects of CPB.