D-dimer levels in blood salvage for autotransfusion

Activation of blood coagulation in patients undergoing postoperative blood salvage and re-infusion of unwashed whole blood after total knee arthroplasty

BACKGROUND

Perioperative blood salvage is commonly used in cardiovascular surgery and has been more recently introduced in major orthopedic surgery. Limited information is available on the influence of re-infused whole blood on the hemostatic system in orthopedic patients.

MATERIALS AND METHODS

The aim of this study was to assess whether perioperative salvage and re-infusion of unwashed whole blood is associated with an activation of blood coagulation in patients undergoing total knee replacement. Consecutive patients receiving re-infusion were included in the study (n=13). Patients undergoing total knee replacement without perioperative blood salvage and re-infusion served as controls (n=6). In patients receiving re-infusion thrombin-antithrombin complexes (TAT), plasmin-antiplasmin complexes (PAP) and fibrinogen were assayed at the following times: before surgery (baseline), immediately before re-infusion (T0), immediately (T1), 2 h (T2) and 24 h (T3) after the end of re-infusion. In control patients blood samples were drawn at the average times corresponding to each of the sampling time in the patients receiving re-infusion. The first post-surgery LMWH dose was given within 12 h after surgery.

RESULTS

TAT and PAP increased after surgery both in patients receiving re-infusion and controls. An increase of TAT and PAP was observed immediately after re-infusion with respect to baseline (TAT 513.1 +/- 259.1 microg/l vs. 5.3 +/- 4.9, p<0.0001; PAP 7408.0 +/- 1892.1 microg/l vs. 461.4 +/- 217.1, p<0.0001) and to controls (TAT 60.4 +/- 26.9 microg/l, p=0.002; PAP 2208.3 +/- 1446.4 microg/l, p<0.001). The levels of TAT and PAP in patients receiving re-infusion remained high at 2 h after re-infusion compared to those of the controls (TAT 124.1 +/- 38.3 microg/l vs. 38.08 +/- 18.9, p=0.016; PAP 5690.7 +/- 1435.5 microg/l vs. 1613.9 +/- 706.0, p<0.001) and decreased 24 h thereafter. Fibrinogen level was lower in patients receiving re-infusion compared to controls.

CONCLUSIONS

Whole blood re-infusion is associated with an activation of blood coagulation in patients undergoing total knee replacement. The clinical relevance of this activation has to be tested in prospective studies with adequate sample size.

The effects of a blood-salvaging device on blood containing a hemoglobin-based oxygen carrier, HBOC-201

OBJECTIVES

Hemoglobin-based oxygen carriers will be used concurrently with intraoperative blood salvage. The effects of salvage and processing on blood containing one such solution (HBOC-201; Biopure Corp, Boston, MA) were studied.

DESIGN

Prospective, randomized.

SETTING

Laboratory.

INTERVENTIONS

Sixteen blood units from healthy volunteers had either HBOC (1,500 mg/dL; n = 10) or normal saline (equivalent volume; n = 6) added. All units were salvaged and processed using a blood salvage device. Samples were analyzed for the concentration and molecular weight distribution of plasma hemoglobin and red cell morphology presalvage (pre) and following processing and washing (post 1). Five of the HBOC units underwent a second 1,000 mL wash (post 2).

MEASUREMENTS AND MAIN RESULTS

Processing and washing decreased the concentration of plasma hemoglobin (mg/dL) in HBOC units (1311 +/- 265 pre to 27.8 +/- 19.6 post 1 to 6.5 +/- 2.19 post 2), but did not change the plasma hemoglobin concentration in saline units (2.05 +/- 1.27 pre v 3.18 +/- 0.79 post 1). Total plasma hemoglobin in HBOC units (6.56 +/- 2.19) was significantly greater than in saline units (3.18 +/- 0.79), even after the second wash (post 2). The concentration of unstable hemoglobin in the plasma phase was not different between groups. Red cell morphology was altered by the salvage process but was not different between groups.

CONCLUSIONS

Salvage and processing of blood containing HBOC yield concentrated red cells that are indistinguishable from those obtained from blood without HBOC. Residual HBOC remains but is unchanged from the HBOC initially administered.

Lipolytic enzyme and phospholipid level changes in intraoperative salvaged blood

Autotransfusion is becoming increasingly popular, mainly because it eliminates the risk of disease transmission. One of the techniques available is intra-operative blood salvage and retransfusion with or without washing of the collected blood. The blood collected during this process is subjected to a variety of chemical and physical insults which can alter the normal composition of the plasma by activating plasma and cellular homeostatic mechanisms. In this study, we measured the plasma levels of total phospholipids, lysolecithin and non-esterified fatty acids, and the lipolytic enzymes phospholipase A2 (PLA2) and lipase in the salvaged blood before and after washing. In the unwashed salvaged blood the mean levels of PLA2, non-esterified fatty acids and lysophospholipids increased by 144, 96 and 149%, respectively, while those of total phospholipids and lipase did not change to any extent. All these substances were reduced to well below the patients circulating plasma levels by washing the collected blood. The changes indicate that the lipid profile of salvaged blood is significantly altered and that potentially dangerous substances such as PLA2 and its metabolites, lysolecithin and non-esterified fatty acids, are present in increased amounts. Washing the blood is recommended prior to reinfusion.

Levels of complement factor C3 and its activated product, C3a, in operatively salvaged blood

In intra-operative blood salvage the collected blood is exposed to traumatized tissue and a synthetic circuit. Because of this exposure it was expected that the complement system, which is a contact system present in plasma, would be activated in salvaged blood. To determine whether this occurs, the plasma levels of the complement factor C3 and its activated fragment, C3a, were measured in intra-operative salvaged blood before and after washing. Samples were obtained from patients undergoing aortic surgery where intra-operative salvage was used. In the unwashed salvaged blood, the level of C3 fell (mean C3: 0.33 g/L) and the level of C3a increased (mean C3a: 1994 ng/mL) compared with the patient circulating levels of C3 and C3a (mean C3: 0.70 g/L, mean C3a: 855 ng/mL) respectively. Washing of the collected blood reduced the C3a level (mean: 346 ng/mL) to the patient's level and reduced C3 to the lower detection limit of the test (less than 0.2 g/L). The raised level of C3a and the reduced level of C3 confirm that the complement system is activated and imply that other complement factors are also activated.

Prospective randomised evaluation of a new cell saving device in elective aortic reconstruction

In order to evaluate the clinical and haematological implications of salvage autotransfusion using the Haemolite device (Haemonetics, Leeds, UK), 67 aortic reconstructions were studied. Bank blood transfused during the operation fell from a median of four units in the control group to zero using the cell saver (P less than 0.0001), and wound drainage decreased from 250 to 200 ml (P = 0.12). Evidence of fibrinolytic and platelet activation was found during salvage, but no bleeding diathesis was encountered. There was no morbidity or mortality related to the technique, and median hospital stay was reduced in autotransfused patients. The Haemolite is a safe effective device for autotransfusion in elective aortic surgery, and can substantially reduce exposure of both patients and staff to the dangers of homologous blood.

Elastase levels in salvaged blood and the effect of cell washing

Blood was salvaged from the operating field of 16 orthopaedic and vascular operations and processed by the Shiley Dideco cell saver for retransfusion. Plasma elastase levels in the salvaged blood were used as a marker of white cell lysosomal granule release. The plasma level of this enzyme was measured by the technique described by Dreher et al. using the immuno-activation (IMAC) system (Merck-Darmstadt, Federal Republic of Germany). The levels of the enzyme rose dramatically in the salvaged blood and were reduced to preoperative levels after washing in the cell saver. Washing of the salvaged blood before retransfusion is effective in reducing the plasma levels of white cell lysosomal contents which have the potential for producing harmful systemic effects.