Homologous blood use and conservation techniques for cardiac surgery in the United Kingdom

Comparison of early period results of blood use in open heart surgery

Background:

Various adverse effects of homologous blood transfusion detected particularly in open heart surgery, in which it is frequently used, lead researchers to study on autologous blood use and to evaluate the patient's blood better. Due to the complications of homologous blood transfusion, development of techniques that utilize less transfusion has become inevitable. We aimed to evaluate the effects of acute normovolemic hemodilution (ANH) in patients undergoing open heart surgery.

Materials and Methods:

In this study, 120 patients who underwent open heart surgery were included. Patients were grouped into three: Autologous transfusion group (Group 1), homologous transfusion group (Group 2), and those received autologous blood and homologous blood products (Group 3). Patient data regarding preoperative characteristics, biochemical parameters, drainage, extubation time, duration of stay at intensive care, atrial fibrillation (AF) development, and hospital stay were recorded.

Results:

A statistically significant difference (P < 0.005) was found in favor of autologous group (Group 1) with respect to gender, body surface area, European System for Cardiac Operative Risk Evaluation, smoking, hematocrit levels, platelet counts, urea, C-reactive protein levels, protamine use, postoperative drainage, frequency of AF development, intubation period, stay at intensive care and hospital stay, and amount of used blood products.

Conclusion:

The use of autologous blood rather than homologous transfusion is not only attenuates side effects and complications of transfusion but also positively affects postoperative recovery process. Therefore, ANH can be considered as an easy, effective, and cheap technique during open heart surgery.

Use of blood products in cardiac surgery

The quantity of blood products used perioperatively during cardiac surgery is known to vary widely between institutions. This study looked at the amount of blood products used perioperatively in 74 consecutive elective cardiac operations in one institution. The results are compared with those from other European centres and a cost analysis carried out. On average 2.33 +/- 0.74 (95% confidence interval 1.93-2.77) units of red cell concentrate were transfused perioperatively per patient. Six (8%) patients received no blood products. In addition a number of preoperative factors were studied in an attempt to identify predictors of transfusion requirements. Age, preoperative haemoglobin, female sex and red cell mass were all found to have some predictive value. In the face of increasing demands on a limited supply of blood products we question the need for cross matching more than four units of red cell concentrate in elective cardiac surgery.

Blood conservation in small adults undergoing valve surgery

OBJECTIVES

A substantial reduction in transfusion requirements for cardiac surgical procedures has been reported. Many of these reports have been described in patients undergoing coronary artery bypass grafting. Patients suffering from rheumatic heart disease in India are usually small and also anemic. This study was conducted to assess blood conservation methods for cardiac valve surgery in this subset of patients.

DESIGN

This was a prospective, randomized study.

SETTING

The study was performed in a New Delhi tertiary care hospital, and the patients were referred from the northern states of India.

PARTICIPANTS

One hundred fifty consecutive patients undergoing elective valve surgery using cardiopulmonary bypass were included. The mean age was 27.7 years and mean weight was 45.2 kg.

INTERVENTIONS

The patients were divided into three groups of 50 each. Group 1 received autologous fresh blood donated before bypass, and both a cell saver and membrane oxygenator were used. The oxygenator contents at the end of perfusion were processed by cell saver. Group 2 patients were reinfused with autologous blood only, and group 3 was a control group. In groups 2 and 3, the blood that remained in the oxygenator at the conclusion of cardiopulmonary bypass was reinfused. A hematocrit of less than 25% was considered an indication for transfusion in the postoperative period.

MEASUREMENTS AND MAIN RESULTS

The mean preoperative hematocrit was 35.5%. A mean of 361.1 mL of autologous blood was collected from group 1 and 303.3 mL from group 2. Group 1 required 15 units of bank blood, group 2, 90 units (p < 0.001), and group 3, 102 units (p < 0.001). Seventy-eight percent of group 1 patients did not receive any donor blood. There was no significant difference in chest tube drainage among the three groups.

CONCLUSIONS

In this unique group of patients whose mean body weight was only 45 kg, autologous blood alone did not decrease blood bank requirements but when combined with a cell saver and membrane oxygenator greatly reduced the need for donor blood.

Autotransfusion after open heart surgery: the oxygen delivery capacity of shed mediastinal blood is maintained

Autotransfusion of mediastinal shed blood after open heart surgery has become a common and accepted procedure in reducing the need for homologous transfusion during the last 15 years. The objectives of the present study were to investigate the oxygen delivery capacity of autotransfused shed mediastinal blood, compared to patient-blood, during cardiopulmonary bypass and in the postoperative period. Ten consecutive patients undergoing elective cardiac surgery were studied. Mediastinal shed blood was collected in the cardiotomy reservoir and retransfused during the first 18 postoperative hours. The oxygen delivery capacity of the blood to the tissues was calculated by use of the oxygen status algorithm (OSA 2.0) programme and measurement of the 2,3-diphosphoglycerate (2,3-DPG) concentration. Autotransfusion volume ranged from 450-1530 ml per patient (median 824 ml). Shed blood had a mean haemoglobin level of 8.8 g/dl and 7.4 g/dl at 1 h and 6 h of autotransfusion, respectively. There were no significant changes of 2,3-DPG concentration in the patient-blood during cardiopulmonary bypass or after autotransfusion compared to preoperative values. P50 for oxygen (3.6 and 3.6 kPa) and 2,3-DPG concentrations (5.3 and 5.1 mikromol/ml erythrocyte) in shed mediastinal blood (1h and 6h postoperatively) were not significantly different compared to patient-blood. The results demonstrate that the oxygen delivery capacity of shed mediastinal blood is maintained and that the oxygen affinity of patient-blood is not influenced by autotransfusion.

Bleeding and use of blood products after heart operations in infants

Recent studies have suggested that postoperative bleeding is decreased in pediatric heart operations if fresh whole blood instead of blood component therapy is used for postoperative transfusions. Because this is in contrast to our practice to use whole blood for only the priming of the cardiopulmonary bypass circuit and then to use blood components for additional transfusion requirements, it was our interest to analyze the bleeding complications and the use of blood products after heart operations in infants. The patient records of the 73 infants operated on in 1992 were reviewed. The chest tube drainage varied from 3 to 51 ml/kg per 6 hours (mean 10 ml/kg) and it did not correlate with any of the tested clinical or laboratory parameters. One infant underwent reoperation because of surgical bleeding. Disseminated intravascular coagulation developed in another patient. Sixty-eight patients (93%) needed red blood cell supplementation. Sixty-eight percent of patients between 1 month and 1 year old could be treated without any other postoperative transfusion except for red blood cell supplementation. In contrast, in the neonates, platelet concentrates or fresh frozen plasma, or both, were used in 61% of the patients. In addition to the known immaturity of the hemostatic system, the increased need for platelet concentrates in the neonates was attributed to longer cardiopulmonary bypass time, deeper hypothermia in association with circulatory arrest, larger dosages of heparin, and more extensive plasma dilution during cardiopulmonary bypass. In conclusion, a low rate of bleeding complications and acceptably low general blood loss can be achieved postoperatively with blood component therapy.

Autologous blood transfusion for pulmonary and mediastinal surgery in 144 patients. The effectiveness of recombinant erythropoietin injection

Preserved autologous transfusions have been performed for elective pulmonary and mediastinal surgery to prevent the adverse effects of homologous transfusions. Autologous blood was collected preoperatively from 144 patients. The collected blood volume ranged from 400 to 1,600 ml with a mean volume of 544 ml. In four patients with benign diseases, 1,200 to 1,600 ml of blood was collected using 3,000 U of intravenous recombinant human erythropoietin (rh-EPO) administered every other day. One hundred twenty-three of these patients (85 percent) did not require a homologous transfusion. In the 84 patients undergoing either a pneumonectomy, lobectomy, or segmentectomy, 68 (81 percent) avoided homologous blood exposure. A patient with rh-EPO who bled 2,000 g during surgery received an autotransfusion of only 1,400 ml and his postoperative course was uneventful. Preserved autologous blood collected after rh-EPO injections is an effective method for minimizing homologous blood transfusions in pulmonary and mediastinal surgery.

Blood conservation and autotransfusion in cardiac surgery

Blood conservation techniques of withdrawal of blood just before surgery, intraoperative blood salvage with Solcotrans (Solco Basle [UK] Ltd.), and profound hemodilution were used in 14 patients undergoing open heart surgery (group I) and compared with equally matched 14 patients who had profound hemodilution only during cardiopulmonary bypass (CPB) and acted as controls (group II). Group I patients required a mean of 255 mL of homologous blood per patient to achieve a target hemoglobin of 8 g/dL compared to group II patients who required a mean of 1,011 mL per patient (p = 0.0001). By using autologous blood there was a marked reduction in homologous blood exposure. Eight patients in group I and two patients in group II required no homologous blood. No adverse events occurred. In the process of conservation of blood in open heart surgery, we found the combination of the above techniques used in Group I patients to be safe and effective.

High-dose aprotinin in cardiac surgery: three years' experience in 1,784 patients

The effect of the proteinase-inhibitor aprotinin on blood loss and homologous blood requirement in cardiac surgery was investigated. In a prospective study, 902 adult patients were treated with high-dose aprotinin (total greater than 5 x 10(6) kallikrein inactivator units [KIU]; group A), while 882 patients without aprotinin administration served as the controls (group C). Both groups were operated on between January 1987 and October 1989, and included patients with primary coronary artery bypass grafting (n = 525 group C, n = 560 group A), valve replacement (n = 292 group C, n = 264 group A), or combined procedures (n = 65 group C, n = 78 group A), as well as cardiac reoperations (n = 91 group C, n = 110 group A). The average blood loss 36 hours postoperatively in the aprotinin group was 679 +/- 419 mL, compared with 1,038 +/- 671 mL in the control group (P less than 0.05). Total homologous blood requirement was also significantly less in group A (942 +/- 1,630 mL) compared with group C (1,999 +/- 2,283 mL) (P less than 0.05), a reduction of 53%. Serum creatinine concentrations did not show intergroup differences on the first postoperative day (group A, 1.2 +/- 0.7; group C, 1.3 +/- 0.5 mg/dL) or on discharge from the intensive care unit (ICU). Thus, impairment of renal function as a consequence of aprotinin treatment was not observed. Three patients developed signs of mild circulatory depression after injection of aprotinin, which responded promptly to vasopressor therapy.(ABSTRACT TRUNCATED AT 250 WORDS)

Conventional blood conservation techniques in 500 consecutive coronary artery bypass operations

With use of a nonpharmacological, simple, and inexpensive program for blood conservation, 500 consecutive patients underwent elective coronary artery bypass grafting without need of homologous red cell transfusions in 493 (98.6%). At least one internal mammary artery was grafted in all but 1 patient, with supplemental saphenous vein grafts. Intraoperatively, autologous heparinized blood was removed before bypass and retransfused at the conclusion of extracorporeal circulation. The volume remaining in the oxygenator and tubing set was returned without cell processing or hemofiltration. Using the hard-shell cardiotomy reservoir from the heart-lung machine, autotransfusion of the shed mediastinal blood was continued hourly up to 18 hours after operation. The mean postoperative mediastinal blood loss was 643 +/- 354 mL, whereas 624 +/- 296 mL was autotransfused. Thirteen patients (2.6%) needed reexploration for bleeding, of whom 7 (7/500, 1.4%) received homologous blood. No other patients required red cell transfusions. In addition, 9 patients were given a mean of 2.6 units of fresh frozen plasma because of suspected coagulopathy. No platelets were transfused, and no cryoprecipitate therapy was undertaken. Thus, in total, 484 patients (96.8%) were not exposed to any homologous blood products during the hospital stay. At discharge, the mean hemoglobin concentration was 121 +/- 14 g/L (12.1 +/- 1.4 g/dL) and the hematocrit, 0.36 +/- 0.04. Postoperative complications were few. There was one in-hospital death (0.2%).

Benefit from combining blood conservation measures in cardiac operations

Conventional blood conservation techniques have been insufficient to decrease transfusion needs in increasingly complex cardiac operations. To evaluate combinations of conservation techniques, 300 patients were divided into three equal groups. Group 1 had intraoperative autotransfusion and return of mediastinal drainage for 4 hours postoperatively. Group 2 had these measures plus intraoperative plasmapheresis. These two groups were given a transfusion for a hematocrit of less than 0.21 on cardiopulmonary bypass. Group 3 was treated with the same measures as group 2 but did not receive transfusions while on pump unless the hematocrit decreased to less than 0.15. The percentage of patients in each group given transfusions in the operating room was 34% in group 1, 28% in group 2, and 7% in group 3 (p less than 0.05). The percentage of all patients receiving transfusions during hospitalization was 68% in group 1, 36% in group 2 (p less than 0.05), and 18% in group 3 (p less than 0.05). Average total units transfused were 2.16 +/- 0.25 in group 1, 0.7 +/- 0.15 in group 2 (p less than 0.05), and 0.37 +/- 0.07 in group 3 (p less than 0.05). The perioperative morbidity rates including myocardial infarctions and strokes were similar. There were no deaths in group 3. Combining complementary conservation measures is effective in reducing homologous blood transfusions, and the need for transfusion can be safely reduced by allowing profound hemodilution during bypass.

Elective coronary artery bypass surgery without homologous blood transfusion. Early results with an inexpensive blood conservation program

Restriction of donor blood transfusions in cardiac surgery should reduce risks of infective contamination and antigenicity. We report a systemic, simple and inexpensive blood conservation program used for 121 consecutive patients who underwent elective coronary artery bypass surgery without need for homologous blood transfusion. The left internal mammary artery was grafted in all cases, in addition to saphenous vein grafts. Autologous, heparinized blood was removed intraoperatively, pre-bypass, and returned to the patient at conclusion of the extracorporeal circulation. The volume remaining in the oxygenator and the tubing set was returned without cell processing or hemofiltration. Using the hard-shell cardiotomy reservoir from the heart-lung machine, autotransfusion of the shed mediastinal blood was continued hourly up to 18 hours after surgery. The mean postoperative mediastinal bleeding was 551 +/- 206 ml, of which 505 +/- 218 ml was autotransfused. No re-exploration for bleeding was required and no homologous red-cell transfusions were given. Five patients each received 1-2 units of fresh frozen plasma because of prolonged bleeding time. Morbidity was low and mortality nil. At discharge the mean hemoglobin was 12.0 +/- 1.4 g/dl and the hematocrit 36.0 +/- 4.2%.

A diathermy suppression filter for external pacemakers

Some patients undergoing cardiothoracic surgery require cardiac pacing. Surgical diathermy interferes with the operation of external pacemakers, and can cause a loss of cardiac output. The addition of a simple two-stage LC filter to the front end of the pacemaker enables cardiac output to be maintained during the use of surgical diathermy. (Although this article refers specifically to the Devices E4160 series pacemakers, the filter can, in principle, be used with any external pacemaker.

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.