Autotransfusion of mediastinal blood in cardiac 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.

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.

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.

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.

Autologous transfusion of shed mediastinal blood after coronary artery bypass grafting and bacterial contamination

BACKGROUND

Autologous transfusion of shed mediastinal blood is often used after coronary artery bypass grafting (CABG). Shed blood has in a few studies been cultured during the first postoperative hours. However, autologous transfusion might in some cases be continued for several hours and no study has yet examined the bacterial contamination of shed blood later than 6 hours postoperatively.

METHODS

Seventy-five patients undergoing electively performed CABG were included. Cultures of shed blood were taken at initiation of the autologous transfusion and the following morning. Infection variables were measured preoperatively and postoperatively. Infectious complications during the first postoperative week were registered.

RESULTS

The frequency of patients with bacterial growth in the first culture was 0.22 (95% confidence interval: 0.12 to 0.31) compared with 0.04 (95% confidence interval: -0.044 to 0.087) in the second culture (p < 0.002). We found no significant difference in infection variables between patients with or without bacterial growth in the cultures. No patients suffered from early postoperative infectious complications.

CONCLUSIONS

There is no further contamination of the shed blood during the period between initiating the autologous transfusion and the following morning.

A meta-analysis of the effectiveness of cell salvage to minimize perioperative allogeneic blood transfusion in cardiac and orthopedic surgery. International Study of Perioperative Transfusion (ISPOT) Investigators

Concern about risks of allogeneic transfusion has led to an interest in methods for decreasing perioperative transfusion. To determine whether cell salvage reduces patient exposure to allogeneic blood, we performed meta-analyses of randomized trials, evaluating the effectiveness and safety of cell salvage in cardiac or orthopedic elective surgery. The primary outcome was the proportion of patients who received at least one perioperative allogeneic red cell transfusion. Twenty-seven studies were included in the meta-analyses. Cell salvage devices that do not wash salvaged blood were marginally effective in cardiac surgery patients when used postoperatively (relative risk [RR] = 0.85, 95% confidence interval [CI] = 0.79-0.92). Devices that wash or do not wash salvaged blood considerably decreased the proportion of orthopedic surgery patients who received allogeneic transfusion (RR = 0.39, 95% CI = 0.30-0.51 and RR = 0.35, 95% CI 0.26-0.46, respectively). No studies of cell savers that wash salvaged blood during cardiac surgery were included. Cell salvage did not appear to increase the frequency of adverse events. We conclude that cell salvage in orthopedic surgery decreases the risk of patients' exposure to allogeneic blood transfusion perioperatively. Postoperative cell salvage in cardiac surgery, with devices that do not wash the salvaged blood, is only marginally effective.

IMPLICATIONS

This meta-analysis of all published randomized trials provides the best current estimate of the effectiveness of cell salvage and is useful in guiding clinical practice. We conclude that cell salvage in orthopedic surgery decreases the proportion of patients requiring allogeneic blood transfusion perioperatively, but postoperative cell salvage is only marginally effective in cardiac surgery.

A meta-analysis of the effectiveness of cell salvage to minimize perioperative allogeneic blood transfusion in cardiac and orthopedic surgery. International Study of Perioperative Transfusion (ISPOT) Investigators

Concern about risks of allogeneic transfusion has led to an interest in methods for decreasing perioperative transfusion. To determine whether cell salvage reduces patient exposure to allogeneic blood, we performed meta-analyses of randomized trials, evaluating the effectiveness and safety of cell salvage in cardiac or orthopedic elective surgery. The primary outcome was the proportion of patients who received at least one perioperative allogeneic red cell transfusion. Twenty-seven studies were included in the meta-analyses. Cell salvage devices that do not wash salvaged blood were marginally effective in cardiac surgery patients when used postoperatively (relative risk [RR] = 0.85, 95% confidence interval [CI] = 0.79-0.92). Devices that wash or do not wash salvaged blood considerably decreased the proportion of orthopedic surgery patients who received allogeneic transfusion (RR = 0.39, 95% CI = 0.30-0.51 and RR = 0.35, 95% CI 0.26-0.46, respectively). No studies of cell savers that wash salvaged blood during cardiac surgery were included. Cell salvage did not appear to increase the frequency of adverse events. We conclude that cell salvage in orthopedic surgery decreases the risk of patients' exposure to allogeneic blood transfusion perioperatively. Postoperative cell salvage in cardiac surgery, with devices that do not wash the salvaged blood, is only marginally effective.

IMPLICATIONS

This meta-analysis of all published randomized trials provides the best current estimate of the effectiveness of cell salvage and is useful in guiding clinical practice. We conclude that cell salvage in orthopedic surgery decreases the proportion of patients requiring allogeneic blood transfusion perioperatively, but postoperative cell salvage is only marginally effective in cardiac surgery.

The effect of postoperative normovolaemic anaemia and autotransfusion on blood saving after internal mammary artery bypass surgery

The efficacy of two blood conservation techniques in decreasing and in preventing the use of homologous blood products was retrospectively studied in 150 patients undergoing internal mammary artery bypass surgery. Patients were matched according to prebypass blood haemoglobin (Hb) content and body surface area and were allocated to one of three groups: in the patients of group 1 (n = 50), normovolaemic anaemia (NA) was accepted postoperatively (haematocrit [Hct] was accepted to a minimum level of 25%); the patients of group 2 (n = 50) were treated with postoperative autotransfusion (AT) of mediastinal shed blood and acceptance of NA. Group 3 (n = 50) contained control patients, not treated with NA or with AT (Hct was accepted to a minimum level of 30%). Patients of group 1 required 3.0 +/- 0.3 units of homologous blood products, but the patients of groups 2 and 3 received significantly more (p less than 0.01) units: 3.9 +/- 0.2 and 4.5 +/- 0.3 units. No donor blood products were needed in 36%, 9% and 5% of the patients in groups 1, 2 and 3 respectively. The net postoperative blood loss was similar in the groups: 1229 +/- 92 ml in group 1, 1098 +/- 74 ml in group 2 and 1243 +/- 72 ml in group 3. However, total blood loss (1982 +/- 135 ml), including the retransfused part (954 +/- 89 ml), was significantly larger (p less than 0.01) in group 2, than in groups 1 and 3.(ABSTRACT TRUNCATED AT 250 WORDS)

Does heparin coating improve biocompatibility? A study on complement, blood cells and postoperative morbidity during cardiac surgery

To evaluate whether the effect of heparin coating the extracorporeal circuit resulted in differences in patient outcome and haemostatic alteration, 24 patients undergoing elective, isolated coronary artery bypass were randomized prospectively to cardiopulmonary bypass (CPB) with heparin-coated circuits (group H, n = 12) or uncoated circuits (group C, n = 12). The technique of CPB, heparinization and its reversal were the same in both groups. We studied complement status (C3d, C3, C3d/C3, C4 and C-function), white blood cell counts with differentiation and the postoperative morbidity. The results confirmed that CPB activates complement and increases neutrophils in both the H and C groups. A significantly lower level of leucocytosis was seen in group H compared to the C group (p < 0.05). The complement function via the classical pathway (C-function), expressed as a percentage of the function of a reference serum pool (the values of normal sera were 75-125%), was significantly reduced in both heparin-coated and uncoated circuits (p < 0.05). There was no significant intergroup difference regarding C3, C3d/C3, C4 and C-function during the study period. A lower frequency of postoperative morbidity was present in the H group. We conclude that heparin-coated surfaces elicit less leucocytosis and decrease postoperative morbidity in patients undergoing cardiac surgery but do not cause a significant difference regarding activation of the complement system as reported by many other investigators.

Impact of autotransfusion after coronary artery bypass grafting on oxygen transport

BACKGROUND

Autotransfusion of shed mediastinal blood after coronary artery bypass grafting (CABG) has been shown to reduce the requirement for allogeneic blood. We have previously demonstrated in non-randomized studies that the oxygen capacity of shed mediastinal blood is similar to the patient's circulating blood and better than stored allogeneic blood. Therefore, we wanted to examine the influence of autotransfusion of shed mediastinal blood on oxygen transport capacity in patients undergoing CABG.

METHODS

A prospective, randomized, controlled study involving 120 patients having elective, uncomplicated CABG was performed. The autotransfusion group received transfusion of shed mediastinal blood for 18 h. Both groups received allogeneic red cells if their hemoglobin concentration decreased below 5 mmol/L. Red blood cell 2,3-diphosphoglycerate (2,3-DPG) was measured preoperatively and at intervals up to the hospital discharged. Hemodynamic measurements as well as blood gas and hemoglobin measurements from samples of arterial and mixed venous blood were used for calculation of oxygen transport capacity.

RESULTS

During the autotransfusion period only 2 patients (4%) in the autotransfusion group required allogeneic blood compared to 11 patients (20%) in the control group. The 2,3-DPG levels in the autotransfusion group were unchanged before and after autotransfusion (4.4 vs. 4.3 mumol/ml erythrocyte). In the control group, 2,3-DPG levels decreased from 4.3 to 3.9 mumol/ml erythrocyte during the same period. There were no differences in the other measured parameters for oxygen transport capacity between the groups.

CONCLUSION

Autotransfusion of shed mediastinal blood conserves the 2,3-DPG level of the red blood cells, while transfusion of stored blood leads to a decrease in 2,3-DPG levels. Autotransfusion had no effect on hemodynamic parameters, oxygen delivery or oxygen extraction.

Cardiac enzymes and autotransfusion of shed mediastinal blood after myocardial revascularization

BACKGROUND

Autotransfusion of shed mediastinal blood reduces blood requirement after coronary artery bypass grafting. Recently, two nonrandomized trials indicated that autotransfusion elevates the levels of cardiac enzymes after cardiac operations.

METHODS

Prospective, randomized controlled studies involving 120 patients (study A) and 15 patients (study B) having elective uncomplicated coronary artery bypass grafting were performed. Autotransfusion of shed mediastinal blood was performed for 18 hours in the patients allocated to autotransfusion. Serum levels of cardiac enzymes were measured. In study B cardiac enzyme levels in shed mediastinal blood and circulating blood were measured 1 hour postoperatively.

RESULTS

Cardiac enzyme levels were significantly elevated in the patients receiving autotransfusion. In patients with a perioperative myocardial infarction. The level of creatine kinase-MB was much higher than in the autotransfused patients without myocardial infarction. The level of cardiac enzymes was higher in shed mediastinal blood compared with circulating blood.

CONCLUSIONS

Postoperative autotransfusion of shed mediastinal blood causes elevation of cardiac enzyme levels after coronary artery bypass grafting.

Adverse effects of postoperative infusion of shed mediastinal blood

BACKGROUND

Postoperative infusion of shed mediastinal blood has been used in an effort to decrease blood usage after cardiac operations. Recent experience has suggested that this practice may actually lead to a delayed increase in bleeding.

METHODS

In a prospective, randomized study, 40 patients undergoing coronary artery bypass grafting with shed mediastinal blood collected in a cardiotomy reservoir were divided into two equal groups and studied during their first 4 hours in the intensive care unit. Shed mediastinal blood was directly infused in group I (n = 20), whereas in group II (n = 20), it was not. In group II, if a sufficient volume of red cells was present to allow processing (n = 5), washed red cells were infused. Variables studied before and after infusion were the amount of blood lost and infused, homologous blood transfused, complete blood count and differential, serum fibrinogen, fibrin split products, D-dimers, clotting factors, prothrombin time, activated partial thromboplastin time, thromboelastograms, plasma-free hemoglobin, complement factors C3 and C4, creatine kinase and its MB isoenzyme, and body temperature.

RESULTS

After infusion of shed mediastinal blood, elevated levels of fibrin split products and D-dimers were found in significantly more patients in group I. The thromboelastogram index was normal in 76% of patients in group II but in only 12.5% in group I. Group I also had an increase in band neutrophils, a greater number of febrile patients, higher serum levels of creatine kinase, its MB isoenzyme, and plasma-free hemoglobin, and greater blood loss during hours 3, 4, and 5 in the intensive care unit. The volume of red cells in shed mediastinal blood (hematocrit, 9% to 10%) was small, resulting in clinically insignificant autotransfusion when infused directly, and insufficient for cell processing in most patients.

CONCLUSIONS

These data support those in previous studies that direct infusion of shed mediastinal blood does not save substantial amounts of autologous red cells and can cause a delayed coagulopathy and other adverse effects that may be harmful to patients postoperatively.

Autotransfused shed mediastinal blood has normal erythrocyte survival

BACKGROUND

Autotransfusion of shed mediastinal blood may reduce the need for homologous blood transfusions in cardiac surgery. In an earlier study we have shown that the red blood cells (RBCs) of shed mediastinal blood have a normal membrane stability (osmotic fragility) compared with circulating RBCs after coronary artery bypass grafting and better than stored RBCs. This indicates that RBCs in shed mediastinal blood are not damaged further during salvage. It remains to be determined how autotransfusion affects the survival of RBCs from shed mediastinal blood.

METHODS

We performed a prospective, randomized, and controlled study involving 26 patients having elective, uncomplicated coronary artery bypass grafting. Dual-isotope labeling technique (chromium 51 and technetium 99m) was used to investigate the 24-hour survival of RBCs from shed mediastinal blood and RBCs from circulating blood, and to estimate the mean survival time of RBCs.

RESULTS

There was no significant difference between the 24-hour survival of shed mediastinal RBCs and circulating RBCs. The estimated mean cell lifespan was 20.5 days (range, 11.6 to 29.0 days) for shed mediastinal RBCs and 22.7 days (range, 14.4 to 36.2 days) for circulating RBCs.

CONCLUSIONS

The survival of RBCs from shed mediastinal blood after autotransfusion is comparable with the survival of RBCs in the patients' circulating blood.

Autotransfusion after coronary artery bypass grafting halves the number of patients needing blood transfusion

BACKGROUND

Several randomized studies about autotransfusion of shed mediastinal blood in patients undergoing coronary artery bypass grafting have resulted in divergent findings concerning reduction of the need for homologous blood transfusions. Most of these studies used less strict criteria for homologous blood transfusion than applied in daily clinical practice.

METHODS

A prospective, randomized, controlled study involving 120 patients having elective, uncomplicated coronary artery bypass grafting was performed. The autotransfusion group received transfusion of shed mediastinal blood for 18 hours. Criteria for homologous blood transfusion were hemoglobin concentration less than 5.0 mmol/L in the intensive care unit and less than 5.5 mmol/L during the rest of the hospital stay.

RESULTS

Twenty-eight percent of patients in the autotransfusion group received homologous blood transfusion versus 55% in the control group (p = 0.007). Ninety-five percent of the shed mediastinal blood was transfused. In the autotransfusion group, a total of 26 units of homologous blood was used versus 78 units in the control group (p < 0.001).

CONCLUSIONS

Autotransfusion of shed mediastinal blood in patients undergoing elective, uncomplicated coronary artery bypass grafting halves the number of patients needing homologous blood and reduces the amount of homologous blood given.

Systemic blood activation during and after autotransfusion

To evaluate the extent of shed blood activation in two autotransfusion systems and the effect of circulating blood activation upon autotransfusion, we performed a prospective study in 18 patients undergoing internal mammary artery bypass operation and a control group of 10 patients. The autotransfusion systems were from Sorin (n = 9) consisting of a hard shell reservoir with a filter having a small contact area (0.32 m2), and from Dideco (n = 9) consisting of a hard shell reservoir with a filter having a larger contact area (4.64 m2). We found high concentrations of thromboxane, fibrinogen degradation products, complement split product C3a, and elastase in the shed blood and, with the exception of C3a, in the circulating blood of autotransfused patients. There was no such activation in control patients. The degree of the systemic inflammatory reaction was determined by the type of autotransfusion system and by the amount of infused shed blood. The Dideco system provoked more inflammatory response than did the Sorin. This was reflected by the larger shed blood loss during autotransfusion in the Dideco patients than in Sorin patients, resulting in infusion of more shed blood (means, 737 mL versus 566 mL; not significant). After autotransfusion, Dideco patients shed significantly more blood than did Sorin or control patients (p < 0.05). Dideco patients also needed more colloid/crystalloid solution per 24 hours than Sorin patients (p < 0.05). This became clinically relevant only after infusion of more than 800 mL of shed blood (p < 0.001): hemodilution indicated the need for packed cells in 4 Dideco patients and in 1 Sorin patient.(ABSTRACT TRUNCATED AT 250 WORDS)

Prospective, randomized trial of autotransfusion after routine cardiac operations

To study the effectiveness of autotransfusion of shed mediastinal blood in decreasing the need for homologous blood transfusion in the routine cardiac surgical patient, we prospectively randomized 35 consecutive patients into two groups. The experimental group (n = 18) received autotransfusion for 12 hours after completion of the operative procedure. The control group (n = 17) was treated with standard chest drainage and fluid replacement. Both groups received homologous blood transfusion when the hemoglobin level fell to less than 8.0 g/dL. Student's t test, chi 2 analysis, and multivariate logistic regression analysis were used where appropriate. Packed red blood cells were required postoperatively in 6 of the 17 control and 6 of the 18 autotransfusion patients (p = not significant). Postoperative colloid fluid replacement (excluding autotransfusion fluid) in the autotransfusion group (333 +/- 78 mL; 95% confidence bounds, 168 to 498 mL) was less than in the control group (615 +/- 114 mL; 95% confidence bounds, 372 to 857 mL; p = 0.048). Total homologous blood product exposure tended to be higher in autotransfusion patients (83%) than in control patients (47%) (p = 0.057). Fibrin split products were elevated only in the serum of the autotransfusion patients (p < 0.002). No transfusion-related complications were apparent in either group. Although the sample size is small, autotransfusion of shed mediastinal blood does not appear to decrease the need for homologous blood transfusion in the routine cardiac surgical patient.

Blood salvage in cardiac surgery

The aim of this study was to evaluate blood salvage provided by an intraoperative blood recovery system (IBRS) and a mediastinal drainage blood recovery system (MBRS) during and after cardiac surgery. Sixty-six patients undergoing aortocoronary bypass surgery were randomly assigned to three groups of 22 patients each. In group I, patients received only homologous blood (HB). Group II and group III patients received the blood content of the oxygenator after concentration by an IBRS at the end of the operation. In group III, patients also received their own mediastinal drainage blood, shed for 6 hours after operation, after concentration and washing in a MBRS. The patients were transfused with homologous blood if needed, in order to obtain a hematocrit of 28% at the end of operation, 30% the following day, and a hemoglobin level over 10 g/dL while on the cardiac surgery ward (8 to 10 days). The three groups were comparable with respect to age, body surface, preoperative and postoperative hematocrits, number of grafts, bypass duration, and postoperative mediastinal blood loss. The amount of HB that was transfused during the operation was significantly lower in groups II and III than in group I (P less than 0.0001). After the operation it was significantly lower in group II than in group I (P less than 0.05), and in group III versus group I. Thus, 13.6% of patients in group II and 38% of patients in group III did not require HB transfusion. No infection, renal dysfunction, or coagulation disorders were observed. It is concluded that the use of an IBRS allows a significant saving of HB. However, because it does not avoid all HB requirements, it should be associated with other techniques to avoid blood transfusion such as the MBRS or predonation.

Open-heart surgery in Jehovah's Witnesses

During a 7-year period, 11 adult members of the religious sect Jehovah's Witnesses underwent cardiac surgery with extracorporeal circulation. No homologous blood transfusions were given. Blood-conserving procedures were employed, viz. initial collection of autologous blood, haemofiltration or processing (Cell Saver) of blood collected during extracorporeal circulation and reinfusion of shed mediastinal blood. The total perioperative blood loss averaged 1080 ml (15 ml/kg body weight), equalling 19% of total body blood volume. The mean haemoglobin on discharge from hospital was 11.0 g/100 ml. There was no perioperative mortality. Postoperative pulmonary function was good and there was no serious morbidity. Jehovah's witnesses with serious, surgery-necessitating heart disease can be offered operation comprising recognized blood-conserving procedures.