Allogeneic blood transfusion, although often needed in major surgery with large per-and postoperative bleeding, is fraught with dangers such as clerical mishandling, immunosuppression and blood-borne infections. It is therefore important to find ways to avoid allogeneic blood transfusion by means of less bleeding, better tolerance of the bleeding or alternatives to allogeneic blood.
Aim of the study: To evaluate different methods of blood saving in total hip replacement (THR) surgery, their efficacy, and the possible risks, especially hyper- and hypocoagulation.
Patients and methods: A total of 179 patients and eight volunteers were included in five studies. All patients were operated by primary TI-IR. Blood loss, allogeneic transfusions, coagulation parameters (platelets, bleeding time, fibrinogen, APTT, PT, soluble fibrin, TAT), fibrinolysis parameters (D-dimer, tPA, PAT, PAP), functional coagulation analysis (Sonoclot, TEG) and frequency of deep vein thrombosis (ultrasonography) were investigated according to the different study regimes. Thitiy patients undergoing predonation of autologous blood (PAD) with or without autotransfusion were compared with a control group of 15 patients without blood saving treatment. Fatty patients undergoing immediate prcopcrative platelet rich plasma (PRP) harvest and autotransfusion were compared with 40 patients undergoing PAD and autotransfusion. The spontaneous and induced activation of the platelets in the blood of20 patients undergoing THR with or without additive PRP harvest were also studied with flow cytometry. The efficacy of tranexamic acid (TA) as a blood saving method was examined in a study including 40 patients. As Sonoclot coagulation analysis was the single most important coagulation analysis during the studies, a methodological examination including eight volunteers was done for the instrument.
Results and discussion: If no blood saving method is used there is a very strong possibility of allogeneic blood transfusion (100% of the patients studied needed blood). Autotransfusion is not sutlicient as a single transfusion reducing method (53% patients studied still needed blood). PAD+ autotransfusion gives sufficient reduction in allogeneic blood transfusion (5-27% of patients in tlte different studies needed blood) but needs prcopcrativc planning, and PAD is not accepted by Jehovah's Witnesses. PRP reduces allogeneic blood transfusion as effectively as predonation of two units of blood (15% of studied patients needed blood) and can replace PAD in unplanned operations and for Jehovah's Witnesses. The majority of platelets are in a resting state during THR and PRP harvest. PRP harvest did not affect the degree of platelet activation, but there were great individual differences between patients (spontaneous activated platelets, i.e. presenting P-Selektin during the operation, between 1 %-23%). Most of the platelets in the c-PRP were not activated at the time ofretransfusion but were easily activated upon stimulation with the physiological activator ADP. TA therapy started prcoperatively is easily performed and reduces bleeding by 35%, probably by significantly reducing induced fibrinolysis perioperatively. During primary THR surgety there was an early postoperative hypocoagulation during the first postoperative day, with a hypercoagulation later postoperativcly, and an observed maximal value about 7 to 10 days postopcrativcly that was still evident three weeks postopcratively. Per- and early postoperatively there was also a marked fibrinolysis that was normalized on day 1 postoperatively. Six of the 120 patients examined with ultrasonography had DVTs, all after the first week postoperatively. There were no differences in the frequency of detected DVTs, irrespective oftrcahnent with PAD, PRP or TA. Sonoclot coagulation analysis was found to be a valuable tool in detecting hypercoagulability but was restricted by a high variability. This variability can be lowered by a dual machine setting, repetitive analysis and directly analyzed arterial samples.
Conclusion: The combination ofperioperative autotransfusion and PAD is effective in preventing allogeneic blood transfusions during primary THR. PRP harvest is as effective as PAD and is useful for patients who cannot donate blood. A minor propotiion of the patient's platelets are activated during the surgery irrespective of whether or not there is PRP harvest. TA therapy started preoperatively reduces fibrinolysis during the day of surgery and reduces per-and postoperative bleeding by 35%. Primmy THR surgery gives rise to an initial hypocoagulation followed by a hypercoagulation with an observed maximal value about 7 to 10 days postoperatively which is still evident three weeks postoperatively. However, the observed frequency of thrombosis was low (5%) in the 120 patients examined with utrasonography. Sonoclot analysis is an efficient tool for following this hypercoagulation. The high variability of the method can be reduced with a dual machine setting, repetitive analysis and directly analyzed arterial samples.
Linköping: Linköpings universitet , 2000. , 58 p.