The influence of acute preoperative plasmapheresis on coagulation tests, fibrinolysis, blood loss and transfusion requirements in cardiac surgery.

OBJECTIVE: Withdrawal of autologous plasma and reinfusion after cardiopulmonary bypass (CPB) offers the opportunity of improving patients' haemostasis and reducing homologous blood consumption in cardiac surgery. The influence of acute, preoperative plasmapheresis (APP) on coagulation tests, fibrinolysis, blood loss and transfusion requirements was investigated in elective aortocoronary bypass patients. METHODS: Forty patients were randomized to a control or pheresis group. The pheresis group had platelet-rich plasmapheresis (PRP-group, n = 20) performed before incision and the platelet-rich plasma (PRP) was returned after CPB. The control group (n = 20) was managed without pheresis. All patients had serial coagulation studies, including prothrombin split products (F1/F2), fibrinopeptide A (FPA), protein C (PC), thrombomodulin (TM), tissue-plasminogen-activator (t-PA), plasminogen-activator-inhibitor (PAI 1), fibrinopeptide B beta 15-42 (FPB beta 15-42), haemoglobin and platelet counts determined intra- and postoperatively. Chest tube drainage and transfusion requirements were recorded. RESULTS: APP had no negative effects on the quality of PRP. The platelet count of the withdrawn autologous plasma was 239 +/- 33 x 10(9)/l. From the end of the operation (after retransfusion of autologous plasma) until the first postoperative day platelet counts were significant higher in the PRP-group (P > 0.05). Plasma concentrations of modified antithrombin III (ATM), F1/F2 and FPA increased (166-290% from baseline) and PC- and TM-antigen decreased (11-49% from baseline) to a different extent for both groups throughout CPB. t-PA-activity increased intraoperatively peaking at the end of CPB (PRP-group: 4.8 +/- 0.8 IU/ml, control-group: 8.1 +/- 2.3 IU/ml)(P > 0.05). With onset of CPB PAI-1 levels decreased and were further reduced after CPB in control patients in comparison to PRP-patients (P < 0.05). FPB beta 15-42 occurred in peak concentrations after neutralisation of heparin by protamine. Only PRP-patients showed baseline values of coagulation and fibrinolytic parameters on the next morning (P < 0.05). Total postoperative blood loss during the first 24 h was 503 +/- 251 ml (PRP-group) and 937 +/- 349 ml in the control-group (P < 0.05). None of the PRP-patients received allogeneic blood, whereas five control-patients received 11 units of packed red cells (P < 0.05). CONCLUSIONS: The findings suggest that in elective cardiac surgery heparin cannot prevent generation of both thrombin and fibrin, born throughout CPB and postoperatively. The use of PRP withdrawn immediately preoperatively is an attractive technique to reduce allogeneic blood usage and preoperative blood loss, especially in patients in whom withdrawal of autologous whole blood cannot be performed.

[The effect of different autotransfusion procedures on the antibiotic picture. A study on cephalosporin cefamandole]. / Der Einfluss unterschiedlicher Autotransfusionsverfahren auf Antibiotikaspiegel. Studie zum Cephalosporin Cefamandol.

Infection after open heart surgery is a serious complication since eradication of infection in these cases is difficult even with appropriate antibiotic therapy. In the attempt to avoid this problem, prophylactic administration of antibiotics is common. Their relative safety and their broad spectrum of activity make cephalosporin antibiotics popular choices for prophylaxis prior to and during operations, including cardiovascular procedures. METHODS. Preoperative antibiotic prophylaxis with 2 g cefamandole was performed in a prospective randomized study including 62 male patients divided into three groups. All patients gave informed consent, and the study was approved by the ethics committee of the hospital. Patients in group 1 (n = 21) and group 2 (n = 21) underwent aortocoronary bypass (ACVB) with extracorporeal circulation (ECC), while patients in group 3 (n = 20) had carotid surgery. Anaesthesia, coronary-bypass procedures and infusion regime were standardized. The flow rate during ECC was maintained at 2.41/min/m2 and the rectal temperature between 33 degrees and 34 degrees C. Arterial and urine specimens for the determination of plasma and urine levels of cefamandole were taken at definite times. Autologous blood salvage during operation was performed with haemofiltration techniques (HF) in group 1 (HF 80, Fresenius, Bad Homburg, Germany) and with cell separation techniques (CS) in group 2 (Hemonetics III, Hemonetics). Plasma and urine cefamandole levels were measured by high-pressure liquid chromatography (HPLC). RESULTS. After administration of 2 g cefamandole mean peak levels of 404.6 +/- 141.7 micrograms/ml were seen. Because of haemodilution at the beginning of extracorporeal circulation, group 1 and 2 showed much lower cefamandole plasma levels, 22.1 +/- 11.6 micrograms/ml and 24.3 +/- 14.4 micrograms/ml, than group 3 (after the same time course), with 47.4 +/- 19.1 micrograms/ml. For all patients in group 1 and 2 prebypass time (70.3 +/- 22.4 min) and the duration of the ECC (72.3 +/- 17.7 min) were comparable. There was a significant correlation between prebypass time and cefamandole plasma levels at the beginning of extracorporeal circulation (P < 0.001). No correlation could be seen for the plasma concentration after discontinuation of the extracorporeal circulation and the duration of extracorporeal circulation. The volume of autologous red packed cells and the enclosed amount of cefamandole showed a significant difference (P < 0.001) between group 1 (1120.0 +/- 296.8 ml, 27.5 +/- 17.1 mg) and group 2 (734.3 +/- 186.6 ml, 2.9 +/- 3.2 mg). The plasma cefamandole level after transfusion of autologous blood displayed a significant correlation (p < 0.01) with cefamandole concentration in the autologous red packed cells. Transfusion of the autologous blood produced no significant increase in plasma cefamandole levels. With an operation time of more than 2.5 h during ECC the cefamandole plasma level decreased below the necessary minimal inhibitory concentration (MIC90), particularly for gram-negative bacteria. CONCLUSION. Additional administration of 1 g cefamandole shortly before the beginning of cardiopulmonary bypass is recommended, particularly for surgical procedures with ECC of more than 2.5 h. Adjustment of drug dosage prior to or during surgery may be required to optimize therapy, but before this can be achieved precisely, more information on drug disposition during the operative procedures is needed.