Biomedical subjects
Publications and source records attributed to B von Bormann.
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Avoidance of homologous blood products and patients' demand for preoperative autologous blood donation programs are increasing. As many of these patients are older, with a compromised cardiovascular system and a slow response of the erythropoietic system when anemia occurs, the feasibility and benefit of autologous blood donation is often limited. Augmentation of preoperative blood donation by therapy with recombinant human erythropoietin (rHuEPO) has been described in animal models and in patients. METHODS. In a multicenter, controlled, randomized trial, 49 patients scheduled for orthopaedic or vascular surgery received 0 (control group, n = 9), 200 (n = 10), 300 (n = 11), 400 (n = 10) or 500 (n = 9) U/kg rHuEPO (Erypo, Cilag, Sulzbach, distributor Fresenius, Oberursel, Germany) subcutaneously twice a week for 3 weeks while every week 450 ml blood was collected. Iron sulphate 100 mg was prescribed orally twice a day. Patients were ineligible if they had uncontrolled hypertension, recent myocardial infarction, haematological disorders or a history of seizures. Blood donation had to be cancelled if the haematocrit was below 30%. RESULTS. There was a significant (ANOVA) drop of the haematocrit value only in the control group, and end-point values for haematocrit and haemoglobin were significantly elevated in the 400 and 500 U/kg groups compared with the control group (Table 9). DISCUSSION. The erythropoietic stimulus of phlebotomy for autologous blood donations is often not efficient enough to guarantee a constant haematocrit. Lowering of the preoperative haematocrit jeopardizes the aim of avoidance of homologous blood transfusions. rHuEPO increased the efficiency of autologous blood collections, as predonation haematocrit values could be preserved in the high-dosage groups. As a consequence, homologous transfusions could be avoided. However, there were broad interindividual differences in the erythropoietic response, possibly due to limitations in iron availability. Adverse effects of rHuEPO therapy, such as hypertension, thrombosis or neurologic disorders, are mostly reported in patients with terminal kidney failure. No such disturbances were observed in the present study. CONCLUSION. rHuEPO ameliorates the preoperative decrease of haemoglobin and haematocrit values due to autologous blood donations in a dose-related fashion. The individually adjusted dosage of rHuEPO and iron supplementation merits further investigation.
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The effect of haemoconcentration of shed blood from operative field during vascular surgery by either centrifugation (cell separation, n = 10) or haemofiltration (n = 10) was investigated. Interest in this in-vitro-study was focused on the quality of the blood concentrated. Various parameters were measured in the patient (before onset of anaesthesia), and in the blood after suction from operative field: 1. shed blood, 2./3. after haemoseparation/-filtration. Both procedures were easy to perform but haemofiltration produced whole blood quicker than the cell-separation technique (1.2:3.0 minutes). All patients had normal parameters. Suction led to an activation of plasma coagulation and an increase of free haemoglobin and elastase. Haemoseparation in contrast to filtration led to an elimination of thrombocytes, elastase, free hemoglobin and all proteins including antithrombin III and fibrinogen; concentration of red cells was more pronounced after separation (hct 55 vs. 35%). Heparin reduction was better after separation but plasma-heparin-levels were in a tolerable range after both procedures (0.21 vs. 0.75 U/ml). None of the procedures was followed by the appearance of activated clotting factors (F XII a). The data presented demonstrate that haemofiltration may be an alternative in intra- and postoperative autotransfusion. The particular advantage of this method is the preservation of plasma proteins after concentration procedure thus avoiding the need for additional application of fresh frozen plasma in patients with significant blood loss.
The hazards of homologous blood transfusions have been controlled but not eliminated by modern blood banking methods. In addition to the possibility of transmission of infectious diseases, blood transfusion has been reported to induce immunosuppression and thereby impair the host resistance of surgical patients. Experimental and clinical research, particularly in cardiac surgery, have encouraged physicians to accept postoperative anemia. The influence of hemodilution on oxygen supply to the tissues was found to be an increase of local oxygen tension. When hematocrit is progressively lowered under normovolemic conditions, blood cell flux per time and tissue unit is maintained at a hematocrit level as low as 20 vol% as a result of an increase of red blood cell velocity. An increasing number of cardiac operations have been performed upon patients belonging to Jehova's witnesses, inducing an average hematocrit of 11 vol% during extracorporeal circulation. The outcome of these patients was similar to that of patients having received blood transfusion in order to elevate oxygen supply. Some recent studies in critically ill patients demonstrate the importance of oxygen consumption as an important criterion in estimating the effect of oxygen transport. It seems to be proven that, in presence of cardiovascular stability, elevation of the hemoglobin level above 9 g/dl does not result in an increase of oxygen utilization. In accordance with the topical literature we suggest that during the perioperative period a hemoglobin level of 8.5 g/dl will become an accepted transfusion trigger. Particular patients will tolerate even much lower levels.
Pharmacokinetic Parameters as Criteria for Clinical Use of Hydroxyethyl Starch Preparations In a study with volunteers (n = 2 x 6) pharmacokinetic data of two only marginally differing starch preparations were investigated. We were able to demonstrate that there exist significant differences in raw materials used which determined the pharmacokinetic data in humans. Newly implemented analyzing methods (LALLS) were used. In addition to the degree of substitution, further differences concerning the position of hydroxyethylization at the anhydroglucose molecule could be documented. The C2/C6 positions of hydroxyethylization at the molecule seem to be most essential. To classify and to differentiate starch preparations we propose to include these data in general informations for clinicians because these differences might determine clinical usage and efficacy.
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As a result of the AIDS crisis, public and physician pressure have increased the utilization of autologous blood products. Attitudes about homologous blood transfusion, however, have changed dramatically in recent years. A large segment of the population undergoing elective surgery is elderly and therefore has a significant incidence of cardiovascular disease and a slow response of the erythropoietic system when acute anemia occurs. However, preoperative autologous blood donation programs require 2-5 weeks to complete; the average yield is only 2.2 units per patient. As a consequence, autologous predonation is underused and homologous transfusion cannot be completely avoided in all patients. For several years recombinant human erythropoietin (rHuEPO) has been available and has been successfully used in the treatment of patients with renal anemia. This study evaluated the effect of r-HuEPO on patients with preoperative autologous blood collection. METHODS. Ten patients of both sexes scheduled for hip arthroplasty underwent a preoperative autologous program. During a period of 23 days prior to surgery autologous blood donation was performed with 7.5 ml/kg withdrawal on four occasions, the last one 5 days prior to surgery. Five patients were randomly treated with subcutaneous injections of rHuEPO (Erypo, Cilag GmbH, Sulzbach; Distributor: Fresenius AG, Oberursel, FRG) 200 IU/kg seven times, starting 3 days after the first blood withdrawal. All patients (n = 10) received oral iron therapy with iron sulphate 304 mg/die (= 100 mg iron/die). Patients with hypertension or recent myocardial infarction were excluded from the study. The hemoglobin level before donation had to be at least 11.0 g/dl. On each study day, a complete blood count and platelets, differential, and reticulocyte count were determined by standard methods as were transferrin, ferritin, and total iron-binding capacity. Blood loss and blood consumption during and after the operation were registered. The indication for blood transfusion (autologous/homologous) was based on hemoglobin values, which were not acceptable below 8.5 g/dl. RESULTS. No side effects of rHuEPO treatment were observed. Blood loss ranged from 650 to 1100 ml intraoperatively and 400 to 950 ml postoperatively with no differences between the groups. Patients with rHuEPO had no autologous red cell concentrates (aRCC) during the operation; two of them had two units of aRCC on the 2nd postoperative day. Two of the patients in the control group had intraoperative blood transfusions (2 and 3 units aRCC, respectively); all patients in this group were transfused postoperatively: 12 of the 20 units collected were utilized. At the onset of the operation the mean hemoglobin value in patients with rHuEPO was 13.5 +/- 0.4 g/dl compared to 11.3 +/- 0.3 g/dl in the controls. Reticulocytes increased significantly during the investigation period. On the 2nd, 3rd, and 4th days of autologous blood collection and before the onset of surgery, the number of reticulocytes was significantly greater in rHuEPO patients than in the controls. Further laboratory variables such as transferrin, ferritin, and total iron-binding capacity did not change significantly during the investigation period; there were no significant differences between the two groups. DISCUSSION. The results of the present study show that rHuEPO leads to an increase in reticulocytes with maintenance of hemoglobin levels during the phlebotomy program. As a consequence, patients with anemia and particular contraindications to homologous blood derivatives (irregular antibodies, Jehovah's Witnesses) may be able to undergo major surgery successfully. The possibility of shortening the intervals between phlebotomies would seem to be of major advantage; our data also suggest that an aggressive autologous blood collection program would increase yields over present programs. In our institute a minimum hemoglobin level of 11.5 g/dl is accepted for autologous donation.(ABSTRACT TRUNCATED AT 400 WORDS)
A 61-year-old female patient scheduled for major vascular surgery had several diseases, including cardiovascular, pulmonary, renal and hepatic insufficiency. Prior operations--major vascular surgery, strumectomy--had led in most cases to severe bleeding complications owing to a known inherited thrombopathia. Therefore, it was questionable whether an operation would be possible at all. Coordination of three medical departments (vascular surgery, anesthesiology and hematology) created an individual transfusion program. Over a period of 6 weeks, autologous blood was collected in the Anesthesiology Department by means of the so-called leap-frog technique, resulting in the availability of 4 units of autologous packed cells plus 9 units of autologous fresh frozen plasma by the day of surgery. During the operation we used a Shiley autotransfusion device (Autotrans). Two days before the preoperation substitution with homologous thrombocytes was started (one highly concentrated unit per day). This was continued until the 4th postoperative day. Operative procedure performed included reconstruction of iliac artery, bilateral profunda plastic and iliac-femoral cross-over bypass grafting. Only autologous blood products were utilized; apart from thrombocytes no further homologous derivatives were required. The patient had a normal recovery period with no episodes of bleeding or hematoma. There was no need for a long hospital stay. The case presented stresses the importance of good cooperation between physicians for successful treatment of our patients in general and effective use of autotransfusion in particular.