The efficacy of postoperative autotransfusion in patients undergoing cardiac operations

Transfusional quality of residual blood from heart—lung machine after extracorporeal circulation

After open-heart surgery using extracorporeal circulation, residual blood from the heart-lung machine was collected, treated by plasmaphaeresis and washed using a Haemonetics Cell Saver. Qualitative, quantitative and bacteriological aspects of the concentrated red cells were studied.

In 13 patients, an average of 500 ml of concentrated washed red cells (CWRC) was obtained with an average haematocrit of 62·3 %; bacteriological cultures were negative in all cases. As far as qualitative aspects were concerned (intraglobular ATP, 2, 3 DPG, deformability, filtrability and resistance to hypotonic solutions), these red cells were always compatible with immediate transfusion. However, the small volume of blood retrieved and the relatively high cost of this technique suggest that its use be restricted to cases of total haemodilution or for patients with rare blood groups, in whom homologous transfusion blood is scarce.

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.

Pentastarch versus albumin in cardiopulmonary bypass prime: impact on blood loss

BACKGROUND

Albumin is commonly used as a volume expander in cardiopulmonary bypass (CPB) prime. Pentastarch, a low molecular weight hetastarch, may provide similar efficacy at decreased cost but is known to alter coagulation profiles. Infectious concerns forced the temporary withdrawal of albumin in our institution. Therefore we evaluated pentastarch as an alternative with regards to perioperative hemostasis and blood loss.

METHODS

One hundred consecutive adult patients undergoing first-time aorto-coronary bypass were given 750 mL of 10% pentastarch (represented as P in calculations) diluted in 1000 mL of Ringer's solution added in their CPB prime. A similar control group of 100 consecutive patients had received 200 mL of 25% albumin (represented as A in calculations) diluted in 1500 mL of Ringer's solution.

RESULTS

Postoperative prothrombin time (PT) was slightly higher with pentastarch (P: 14.9 +/- 1.5 seconds, A: 14.2 +/- 1.3 seconds, p = 0.003). Postoperative bleeding was also increased (P: 2337 +/- 1242 mL, A: 1981 +/- 1121 mL, p = 0.034), mostly because of recirculated shed mediastinal blood (P: 834 +/- 499 mL, A: 640 +/- 388, p = 0.002) rather than lost pleural tube blood (P: 1503 +/- 821 mL, A: 1341 +/- 824 mL, p = 0.16). Overall net blood loss (P: 2014 +/- 914 mL, A: 2061 +/- 1015, p = 0.73) was similar. Blood-product transfusion requirements and postoperative daily hematocrits did not differ.

CONCLUSION

The diminished coagulability associated with this dose of pentastarch resulted in increased postoperative bleeding. However, with recirculation of shed mediastinal blood, there was no net increase in blood loss. In this setting, pentastarch may serve as a suitable alternative to albumin.

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)

[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.

[Quality of blood salvaged in orthopedic surgery by washing swabs]

OBJECTIVE

To establish the feasibility and safety of recuperating blood absorbed by swabs used during orthopaedic surgery.

STUDY DESIGN

Open, prospective study.

PATIENTS

Included were children undergoing potentially haemorrhagic orthopaedic surgery for whom intraoperative blood salvage seemed possible. Excluded were those with contraindications for this procedure such as septic surgery and cancer surgery.

METHOD

Intraoperative swabs used within the surgical field were collected by a surgical assistant, also in charge of weighing and washing them. The liquid was collected by the aspiration system of a recuperation-washing machine (RWM). The salvaged red blood cells were collected and retransfused at the end of surgery. Several samples of the washing liquid of the swabs and salvaged blood were taken during the procedure. The correlation between the quantity of blood shed and salvaged was calculated. The biological and clinical tolerance of the transfusion was assessed.

RESULTS

Twelve patients undergoing surgery for scoliosis have been included. An average of 278 mL of blood were salvaged. In the washed cell concentrates the haematocrit was 54% and the free haemoglobin concentration was 3.84 g.L-1. All the bacteriological tests were negative over the first 24 hours.

CONCLUSION

Provided that a strict operatory protocol is followed, this study demonstrates the possibility of recuperating blood from swabs used during major orthopaedic surgery.

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.

Reinfusion of mediastinal blood in CABG patients: impact on homologous transfusions and rate of re-exploration

BACKGROUND

Reinfusion of mediastinal shed blood after cardiac surgery has been used in some centers to reduce exposure to homologous blood transfusions. The method has not been widely applied mostly because some studies have failed to demonstrate a significant benefit.

METHODS

A group of 675 consecutive patients undergoing first-time, isolated coronary artery bypass surgery (CABG) was studied. Prospective data was collected on the first 375 patients receiving autotransfusion (ATS) of mediastinal shed blood. The charts of 338 patients immediately preceding the institution of the ATS program at our institution (NO ATS group) were retrospectively reviewed. Transfusion of homologous blood products and rate of re-exploration for bleeding were closely monitored.

RESULTS

The two groups were identical. The net blood loss was significantly less in the ATS group than in the NO ATS group (1013 +/- 431 cc vs 1371 +/- 631 cc, p < 0.0001). Rate of exploration for postoperative bleeding was 1.5% in the ATS group and 5.0% in the NO ATS group (p < 0.01). In the ATS group, 51.9% of patients were not exposed to any homologous blood product (vs 17.8% in the NO ATS group, p < 0.0001). The ATS patients received on the average 2.9 +/- 7.2 units of blood products versus 6.4 +/- 9.7 units in the NO ATS group (p < 0.0001).

CONCLUSION

Reinfusion of mediastinal shed blood significantly reduces exposure to homologous blood transfusions and rate of reexploration. The ATS system reduces the number of re-explorations for coagulopathy-related postoperative hemorrhage.

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.

Conservation of blood during cardiovascular surgery

Conservative use of allogeneic red blood cell (RBC) transfusion is a growing trend in cardiovascular surgery. Recent advances in blood conservation measures have reduced, and in some cases eliminated, the need for allogeneic RBC transfusions in some of these patients. Reduced reliance on allogeneic RBC transfusion requires close collaboration among the clinical pathology, anesthesia, and surgery services managing the patient. Preoperative conservation measures include donation of autologous blood and treatment with recombinant human erythropoietin (Epoetin alfa). Meticulous surgical technique, moderate hemodilution, aprotinin, hemostatic techniques, blood salvage, and autotransfusion are intraoperative measures that can reduce blood loss. Postoperatively, even severe blood deficits can often be restored with adequate diet and rest and the use of actinics.

Autotransfusion: is there a benefit in a current practice of aggressive blood conservation?

Findings from early studies suggested that the autotransfusion of shed mediastinal blood (ATS) after cardiac surgical procedures led to a reduction in the postoperative banked blood requirements. However, changes in baseline patient characteristics and other blood conservation methods may now negate the benefits of ATS. To determine whether the routine use of ATS is effective in the context of current surgical practice, risk factors related to postoperative banked blood requirements were analyzed in a prospective series of 155 consecutive patients undergoing cardiac operations: 71 patients before and 84 patients after the addition of ATS to an already aggressive standardized blood conservation protocol. The overall mean patient age was 66 +/- 11 years; the mean preoperative patient hemoglobin level was 11.8 +/- 1.8 g/dL; 48% of the procedures were elective and 12% were reoperations; coronary artery bypass grafting was performed in 73% of the patients and valve repair or replacement in 34%, with no differences between the non-ATS and ATS groups (all, p = not significant). The mean 24-hour postoperative blood loss was 1,278 +/- 814 mL in the non-ATS group and 1,721 +/- 1,510 mL in the ATS group (p < 0.03). The mean volume autotransfused in the ATS group was 1,122 +/- 97 mL. The overall reoperation rate for bleeding was 0.6% (70% confidence interval, 0 to 1.3%) and the hospital mortality was 1.9% (70% confidence interval, 0.8% to 3.1%), which did not differ between the non-ATS and ATS groups (both, p = not significant).(ABSTRACT TRUNCATED AT 250 WORDS)

Shed blood autotransfusion influences ischemia-sensitive laboratory parameters after coronary operations

The diagnostic significance of ischemia-sensitive laboratory parameters in respect to possible interference with shed blood autotransfusion was assessed in a prospective study with 100 patients undergoing elective coronary artery bypass grafting. Serum levels of creatine kinase, creatine kinase MB activity, creatine kinase MB mass concentration, 2-hydroxybutyrate dehydrogenase, lactate dehydrogenase-1, troponin-T, myoglobin, and glutamicoxaloacetic transaminase were repeatedly assessed up to the sixth postoperative day. Thirty-seven patients were excluded from the study due to postoperative development of myocardial infarction (n = 4), transient ischemic events (n = 25), and left bundle-branch blocks (n = 8). In the remaining group of 63, 37 patients were retransfused with 580 +/- 370 mL shed blood up to the twelfth postoperative hour, and 26 patients did not receive autotransfusion due to minimal mediastinal blood loss. The results of our study show that the ischemia-sensitive laboratory parameters were significantly influenced by shed blood autotransfusion: 8 hours postoperatively, creatine kinase (272%), creatine kinase MB fraction (151%), 2-hydroxybutyrate dehydrogenase (130%), lactate dehydrogenase-1 (133%), troponin-T (200%), myoglobin (159%) and glutamic-oxaloacetic transaminase levels (153%) were significantly elevated (p < 0.05) in patients with postoperative autotransfusion, although there were no electrocardiographic signs of myocardial ischemia in this group of patients. Our study shows that postoperative autotransfusion of mediastinal shed blood may interfere with the diagnosis of perioperative myocardial ischemia by laboratory parameters in coronary bypass patients.

Safety and therapeutic effectiveness of reinfused shed blood after open heart surgery

This prospective study was designed to determine whether use of nonwashed shed mediastinal blood exacerbated platelet and related hematologic dysfunctions after cardiopulmonary bypass, compared with the alternative use of autologous and homologous standard liquid preserved blood for volume support. Thirty-two patients undergoing cardiopulmonary bypass for open heart operations were randomized to receive either nonwashed shed mediastinal blood (group 1; n = 16) or liquid preserved packed red blood cells (group 2; n = 16) for transfusion therapy in the management of postoperative bleeding. Patient blood samples and bleeding times were obtained preoperatively, after cardiopulmonary bypass but before transfusions, 2 and 24 hours after transfusion, and on postoperative days 2, 3, and 7. Group 1 patients received an average of 710 +/- 90 mL (range, 300 to 1,700 mL) of nonwashed shed mediastinal blood containing significantly greater (p < 0.0001) amounts of fibrin degradation products and D-dimer protein. Of the hematologic, microaggregate, and plasma protein measurements performed, only the protein C level was significantly greater in group 1 (p < 0.05) after transfusion. Patient bleeding times were not significantly different between the groups at any of the time points, and the total postoperative blood loss was not different between the groups. There was a trend toward less need for homologous transfusion in group 1 (p < 0.1). This study documents the safety and ease of using nonwashed shed mediastinal blood as a primary blood volume support after an open heart operation.

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.

Reinfusion of whole blood following addition of tobramycin powder to the wound during total knee arthroplasty

This study prospectively examined nine human volunteers who underwent unilateral cementless total knee arthroplasty and had 600 mg of tobramycin powder added to their wound just prior to fascial closure. Serum levels of tobramycin were measured at 30 minutes, 4 hours, 8 hours, and 12 hours after surgery. Tobramycin levels in the reinfused whole blood were measured with each reinfusion. Patients were reinfused up to 12 hours after surgery and then the reservoir was left to suction drainage. All patients had significant levels of serum tobramycin 30 minutes after surgery. The average serum level was 5.5 micrograms/ml (range, 3.0-10.6 micrograms/ml). This level was achieved prior to any reinfusion and represented systemic absorption of tobramycin from the bleeding surfaces of the muscle and bone. All patients received at least one reinfusion of 400 ml of whole blood in the first 8 hours after surgery. Two thirds of the patients received a second reinfusion within the same time frame. Serum tobramycin levels measured post-reinfusion indicated that the risk of attaining potential toxic levels of aminoglycoside was not dependent on reinfusion, but on absorption from the wound. The dose of tobramycin in the drain was measured and found to be excessive and potentially toxic (range, 27-312 mg; average, 132 mg). Despite this fact, reinfusion was not as likely to produce toxic serum levels as was local uptake of the antibiotic. Although no patient in this series had any complaints relating to the high dose of tobramycin (deafness or renal failure), caution should be exercised when using antibiotics in a reinfusion system.(ABSTRACT TRUNCATED AT 250 WORDS)

Reinfusion of whole blood after revision surgery for infected total hip and knee arthroplasties

Because of its proven effectiveness in reducing the need for banked blood transfusions following total joint arthroplasty, the indications for postoperative blood retrieval were expanded to include seven cases of infected total knee or hip arthroplasties where a one-stage exchange procedure was performed. Each joint had been aspirated after surgery and had positive cultures but no gross pus at the time of revision surgery. Each of the operations included debridement with reimplantation of a cementless prosthesis under cover of intravenous antibiotics for 48 hours followed by oral treatment until discharge. Antibiotic-soaked morselized bone graft was used in all patients to restore deficient nonstructural bone. Wound drainage blood was retrieved and reinfused during the first 8 hours after surgery, averaging 958 cc. Banked blood usage averaged 2.4 U (88% homologous) with an average blood loss of 1,974 cc. One patient experienced shaking chills during a second reinfusion of 600 cc of blood without stoppage of the transfusion. Wound hematoma occurred in one patient but did not require surgical evacuation. No patient developed evidence of septicemia.

[Effects of postoperative autotransfusion in prosthetic surgery of the hip with the ConstaVac device]

A new device for postoperative autotransfusion (ConstaVac, Stryker) was assessed after total hip replacement in 43 patients, mean age 63 +/- 13 years. Intraoperative blood was administered to 27 patients (63%), autologous blood only in 19, homologous blood only in 6 and both autologous and homologous blood in 2. The blood shed during an average 5-hour postoperative period had an haematocrit of 23 +/- 7% and included only few platelets (72 +/- 83 G.l-1). It did not clot as it contained there was less than 0.1 g.l-1 of fibrinogen and a high concentration of D-dimers. In 30 patients (70%), the amount of blood thus collected exceeded 200 ml. An average of 327 +/- 131 ml were subsequently retransfused to these patients. Postoperative autotransfusion induced a moderate but significant decrease in platelet counts (205 +/- 66 vs. 224 +/- 67 G.l-1, p < 0.02) and fibrinogen concentrations (2.3 +/- 0.7 vs. 2.4 +/- 0.6 g.l-1, p < 0.03), and an increase in circulating D-dimers (p < 0.001). Coagulation tests, free plasma haemoglobin and potassium concentrations were not significantly altered. Since the haematocrit of the blood lost was lower than that of the patients', the haematocrit did not increase significantly. Posttransfusion shivering occurred in two patients (7%). Bacteriological cultures of the lost blood and of venous samples obtained after postoperative autotransfusion remained sterile. Postoperative autotransfusion is a simple technique with few side-effects, which might be safely associated with other methods used to decrease the rate of homologous blood transfusion.

Postoperative blood retrieval and transfusion in cementless total knee arthroplasty

Postoperative wound drainage was aspirated, collected, and transfused in 197 patients undergoing unilateral or bilateral cementless knee arthroplasty using the Solcotrans or the Constavac Blood Conservation blood-retrieval devices. Operative technique, method of hemostasis, and postoperative management were identical in all patients. Drainage-tube suction pressure was minimized, and the duration of drainage collection was less than 8 hours in all patients. In the 153 patients who underwent unilateral total knee arthroplasty (TKA), the amount of blood retrieved and transfused averaged 829 cm3 (59% of total blood lost). For the 44 patients who underwent bilateral procedures, 1,131 cm3 of blood was salvaged (56% of total blood lost). Transfused banked blood averaged 1.7 units (25% homologous) in unilateral cases, while bilateral procedures required 3.0 units (35% homologous). Complications (4%) included wound hematomata in five patients and deep venous thrombosis in two. Transient chills, fever, or tachycardia were seen in four patients at the time of transfusion. Transfusion requirements of banked blood appeared to be significantly reduced, especially in simultaneous bilateral knee arthroplasty, when compared to previous experience in patients who did not undergo postoperative blood retrieval.

Reinfusion of shed blood after coronary operation causes elevation of cardiac enzyme levels

We studied the effect of reinfusing mediastinal and chest tube drainage (autotransfusion) after coronary artery bypass grafting on circulating levels of creatine kinase, lactate dehydrogenase, and serum glutamic-oxaloacetic transaminase in 20 patients. Reinfusion of 469 +/- 171 mL (mean +/- standard deviation) of drainage caused enzyme levels to rise to 372% (creatine kinase), 159% (serum glutamic-oxaloacetic transaminase), and 143% (lactate dehydrogenase) of their levels before autotransfusion. The MB fraction of the circulating creatine kinase was not elevated. Enzyme changes caused by autotransfusion can potentially mimic or mask the presence of perioperative myocardial infarction. Enzyme determinations after coronary artery bypass grafting must be carefully interpreted when reinfusion of shed blood is used as a blood salvage technique. Routine measurement of these enzymes after operation may not be warranted.

Autotransfusion of unwashed mediastinal shed blood fails to decrease banked blood requirements in patients undergoing aortocoronary bypass surgery

Infusion of unwashed mediastinal shed blood (MSB) is one technique advocated for decreasing use of donor blood in cardiac surgery patients. A commercially available system was prospectively evaluated in 96 consecutive patients. The control group was comprised of 78 consecutive patients. All underwent elective aortocoronary bypass surgery. Student's t-test, chi-square analysis, multivariate analysis, and Fisher's exact test were used where appropriate. There was no decrease in the amount of banked blood required or percentage of patients who received transfusions in the MSB autotransfusion group.

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.

Haematological effects of reinfused mediastinal blood after cardiac surgery

OBJECTIVE

To explore the risk of inducing a coagulation defect in cardiac surgery patients by the reinfusion of mediastinal blood.

DESIGN

Ten patients who underwent coronary artery surgery were prospectively studied for the haematological effects of reinfusion of blood drained from the chest drain tubes after the operation by a Sorenson autologous transfusion system.

SETTING

Surgery was performed at a private hospital and patient selection was made at the time of reinfusion.

PATIENTS

Nine patients had primary coronary artery surgery and one had a reoperation.

MAIN OUTCOME MEASURES

Blood samples were taken from the patients before reinfusion, one hour after reinfusion, and 24 hours later as well as from the collected blood. Measurements were made of the haemoglobin content, white cell and platelet counts, fibrinogen and fibrinogen degradation products, D-dimer, antithrombin III and plasma haemoglobin content. Estimations were also made of the prothrombin time, the thrombin clotting time and the activated partial thromboplastin time. The hypothesis to be tested by this study was that the reinfusion of mediastinal blood after the operation did not cause any significant disturbance of the patient's blood clotting profile.

RESULTS

An average of 535 mL (range, 400-950 mL) was reinfused after a period of three hours drainage (range, 45 minutes to 5 hours). While the initial patient samples contained a raised plasma haemoglobin level (0.19 g/L) significantly related to the cardiopulmonary bypass time (P less than 0.001), these were free of fibrinogen degradation products except for a sample from one patient who had a reoperation. The blood drained by the Sorenson system was lower in haemoglobin content (7.7 g/dL), and had a significant content of fibrinogen degradation products (147 mg/L) and D-dimer (6.4 mg/L) together with reduced clotting factors when compared with the patients' blood. After reinfusion, the patient sample showed evidence of altered coagulation with mildly increased clotting times (activated partial thromboplastin time 57 s, thrombin clotting time 123 s), the extent of which was related to the volume reinfused (P less than 0.001), but 24 hours later, these effects had all disappeared. All samples were sterile in aerobic and anaerobic culture media.

CONCLUSION

We conclude that the Sorenson system of retrieval of mediastinal blood after cardiac surgery provides a safe and simple method of blood conservation provided that the volume of reinfusion is not excessive.

The stratification of cardiac surgical procedures according to use of blood products: a retrospective analysis of 1480 cases

The use of blood products in 1480 consecutive cases of adult cardiac surgical procedures over a period of 15 mth was studied retrospectively using the database of the Department of Anaesthesia of the Institut de Cardiologie de Montréal. Use of blood products was compared in patients having (1) coronary artery bypass grafting, (2) valvular surgery, (3) or a combination of 1 and 2. First operations were compared with reoperations. Overall, the use of homologous blood products was greatest in patients of Group 3, intermediate in patients of Group 2, and smallest in patients of Group 1. Reoperations were associated with an increase in intraoperative transfusion of packed red blood cells, but postoperative chest drainage was similar to first operations. When all blood products (packed red blood cells, fresh frozen plasma and platelets) were taken into consideration, patients undergoing primary CABG or valve surgery were the least exposed to homologous blood donors (five and six units transfused respectively). Repeat CABG was associated with an intermediate exposure to homologous blood products (eight units). Finally, primary and repeat combined procedures, and repeat valve surgery were associated with the greatest exposure to foreign blood products (10, 13 and 10 units respectively). The data presented in this study provide a rational basis for stratification of procedures according to the expected use of blood products, particularly in view of future studies which may be planned to examine the efficiency of blood conservation strategies.

Autotransfusion after open heart surgery: characteristics of shed mediastinal blood and its influence on the plasma proteases in circulating blood

Fourteen patients undergoing open-heart surgery received intermittent or continuous postoperative autotransfusion of shed mediastinal blood (minimum 400 ml during 6 h after surgery) collected in the cardiotomy reservoir. Hematologic variables and changes in the coagulation, fibrinolytic and plasma kallikrein-kinin systems were investigated in the reservoir blood at the beginning and after 6 h of autotransfusion, and in patient blood during and after surgery and before and after autotransfusion. Autotransfusion volume ranged from 400 to 1200 ml per patient (median 482 ml). The reservoir blood had a median haemoglobin level of 93 and 74 g/l, a platelet count of 71 and 119 x 10(9)/l, and plasma haemoglobin level of 3110 and 4100 mg/l before and after 6 h of autotransfusion, respectively. Further examination of the reservoir blood showed that it had undergone extensive coagulation and fibrinolysis as well as a moderate activation of the kallikrein-kinin system. Despite these extensive alterations in the reservoir blood, no major change could be found in the circulating blood after autotransfusion, except for a moderate increase in plasma haemoglobin from 180 mg/l to 430 mg/l. The clinical safety and simplicity of this technique were confirmed for autotransfusion of shed mediastinal blood up to 1200 ml.

Blood conservation in cardiac surgery

We reviewed current blood conservation techniques and their use in cardiac surgery. Avoidance of aspirin preoperatively is an important blood conservation measure. Patients scheduled for an elective operation should participate in autologous predonation programs. With careful monitoring, patients with major coronary artery disease can safely donate blood preoperatively. Intraoperative processing of blood withdrawn before cardiopulmonary bypass provides autologous platelet-rich plasma for infusion after reversal of heparin sodium. Blood collected from the field during operation and blood remaining in the oxygenator after bypass can also be processed to yield washed and concentrated red blood cells for reinfusion. Randomized, prospective studies document that postoperative autotransfusion is both safe and effective in reducing homologous blood use. Aprotinin reduces plasma protein activation and platelet damage during bypass. The integration of available blood conservation techniques into a comprehensive program combined with careful consideration of the indications for transfusion may allow more patients to avoid transfusion entirely.

Acute plasmapheresis during cardiac surgery: volume replacement by crystalloids versus colloids

Acute plasmapheresis (APP) is an additional tool for blood conservation during cardiac surgery. In a randomized study of 60 aortocoronary bypass patients undergoing APP, the influence of replacement of the withdrawn autologous plasma (10 mL/kg) by either colloids (low molecular weight hydroxyethyl starch solution [6% HES 200/0.5]) or crystalloids (Ringer's solution) was investigated. APP was performed by means of a centrifugation technique producing platelet-poor plasma. During and after cardiopulmonary bypass (CPB), either a cell saver (CS) or a hemofiltration (HF) device was also used for blood concentration. Almost three times as much crystalloid as HES solution was necessary for replacement of autologous plasma. Fluid balance during CPB was significantly more positive in the crystalloid patients, particularly when a CS was used. Blood loss was highest in the crystalloid patients in whom a CS was used in addition to APP, and these were the only patients who needed packed red cells. The platelet count, AT-III and fibrinogen plasma concentrations, colloid osmotic pressure, albumin, and total protein were significantly less compromised in the patients with colloid volume replacement. These parameters were closest to control values in patients receiving colloid replacement and HF. It is concluded that colloid is preferred for replacement of autologous plasma withdrawn by APP, and HF is superior to the CS when the combined technique for blood conservation is used.

Hard-shell cardiotomy reservoir for reinfusion of shed mediastinal blood

We conducted a prospective, randomized, controlled trial comparing homologous blood consumption between groups of patients receiving conventional mediastinal drainage (group 1) or reinfusion of shed mediastinal blood (group 2) using hard-shell cardiotomy reservoir. One hundred consecutive patients who had elective coronary artery or valvular operations were studied. The two groups were comparable with regard to age, sex, weight, preoperative and postoperative hemoglobin levels, and surgical procedure. Group 2 patients had their shed mediastinal blood reinfused for up to 18 hours postoperatively; otherwise, the two groups were treated identically. For groups 1 and 2, average mediastinal blood losses were 705 +/- 522 and 822 +/- 445 mL and homologous blood consumption was 3.83 +/- 2.58 and 3.15 +/- 2.05 U, respectively (neither measure was significantly different). However, if blood losses exceeded 500 mL, there was a statistically significant reduction in homologous blood requirements in group 2 as compared with matched controls in group 1. This difference was most significant in patients with the greatest mediastinal losses.

Apparent coagulopathy caused by infusion of shed mediastinal blood and its prevention by washing of the infusate

We found that reinfusion of shed mediastinal blood (SMB) after a cardiac operation was associated with laboratory evidence of disseminated intravascular coagulation. In view of this, we compared the effect of infusing washed or unwashed SMB on the coagulation profiles and blood use of two serial groups of patients undergoing cardiopulmonary bypass. We found that the results of testing for fibrin degradation products converted from negative to positive in 17 of 20 patients who received unwashed SMB versus 1 of 14 patients who received washed SMB (p less than 0.0001). Other coagulation studies did not reveal disseminated intravascular coagulation in either group, nor were there differences in blood use between the two groups. The unwashed SMB contained high titers of fibrin degradation products (mean reciprocal titer = 354 +/- 161) compared with washed SMB (mean reciprocal titer = 34 +/- 18) (p less than 0.01). Based on the volume of SMB infused, the amount of fibrin degradation products in unwashed SMB was sufficient to account for the positive fibrin degradation product assays after infusion in this group. We conclude that infusion of unwashed SMB may confuse the interpretation of tests for disseminated intravascular coagulation or fibrinolysis. As this could lead to unnecessary blood component use and is preventable by washing before infusion, we recommend that the routine infusion of unwashed SMB no longer be employed.

Effect of blood conservation efforts in cardiac operations at the Mayo Clinic

In a retrospective study of 388 patients who had undergone cardiac operations at our institution during two time periods-before (1982) and after (1984) introduction of autologous transfusion-we analyzed the effect of blood conservation efforts and autologous transfusion on blood usage, postoperative complications, and duration of hospitalization. Cell salvage techniques resulted in a significant reduction (P less than 0.0001) in use of not only homologous blood (from a mean of 9.6 units per patient in 1982 to 3.2 units in 1984) but also fresh-frozen plasma and platelet concentrates. We found no significant difference in morbidity or mortality for the two study periods. Although the mean duration of hospitalization decreased from 11.7 days in 1982 to 9.6 days in 1984, this change was probably related to factors other than the introduction of blood conservation efforts. Thus, techniques used to decrease the amount of blood replacement needed for cardiac surgical procedures are beneficial.

Transfusion of predonated autologous blood in elective cardiac surgery

Despite blood conservation techniques, the average transfusion requirement in patients undergoing elective cardiac surgical procedures remains 1 to 3 units. We studied the efficacy of predonated autologous blood in decreasing homologous transfusion in two matched groups of 58 patients each. Group 1 received homologous blood perioperatively, and Group 2 was transfused with predonated autologous blood. An average of 1.97 units was predonated in Group 2 over 18 days. This resulted in a decline in whole blood hemoglobin concentration of 2.2 gm/dl. No complications resulted from phlebotomy in this ambulatory population consisting predominantly of patients with coronary artery disease. Transfusion of an average of 1.7 units of autologous blood in Group 2 reduced the volume of homologous transfusion by 46% compared with Group 1 (p less than .01). In Group 1, 38% of patients required no homologous transfusion compared with 64% in Group 2 (p less than .02). There were no complications related to autologous blood transfusion. Total transfusion requirement was related to the length of cardiopulmonary bypass. We conclude that autologous predonation is a simple, safe, and cost-effective method of reducing homologous transfusion and thereby decreasing the risk of transfusion-related reactions and infections.

Postoperative autotransfusion of concentrated drainage blood in cardiac surgery. Experience with a new autotransfusion system

A new autotransfusion system was evaluated postoperatively in six patients undergoing aortocoronary bypass surgery. A hollow fiber hemofilter was integrated in the system, making it possible to concentrate the shed blood. The device functioned well, 825 ml diluted mediastinal drainage blood with a hematocrit of 23 was concentrated to a volume of 475 ml with a hematocrit of 36 and retransfused. Proteins were preserved, thus albumin concentration increased from 23 to 37 g/l in the autotransfusate. No negative side effects were registered after autotransfusion. A thorough coagulation study after retransfusion did not reveal any sign of activation of the coagulation cascade, nor were there any signs of an increased fibrinolysis.

An improved technique for autotransfusion of shed mediastinal blood

A technique for autotransfusion of shed mediastinal blood using the cardiotomy reservoir is described that offers several advantages over currently available autotransfusion systems.

Determinants of blood utilization during myocardial revascularization

Blood transfusion during cardiac surgical procedures has steadily decreased, but little information is available regarding the factors that determine its necessity or amount. To determine the predictors of blood utilization during myocardial revascularization, 441 consecutive patients undergoing primary myocardial revascularization were studied. Forty-four patients (10%) received blood during hospitalization with a mean transfusion of 0.3 +/- 1.4 units per patient. Age, sex, weight, body surface area, preoperative hematocrit, blood volume, and red blood cell volume were examined univariately for trends. All demonstrated a statistically significant trend for both need and amount of transfusion (p less than 0.001). Neither number of grafts nor duration of cardiopulmonary bypass demonstrated statistically significant trends. All univariately significant factors were evaluated by multivariate logistic regression analysis. Red cell volume was the best predictor of the need for transfusion (p less than 0.001), followed by age. No other factors improved predictive capabilities. We conclude that preoperative red cell mass and age are the principal determinants of the need for and quantity of blood transfused during myocardial revascularization. Use of this information may greatly improve the efficiency of ordering blood before operation.