Autotransfusion with cell saver for off-pump coronary artery bypass surgery: a randomized trial

OBJECTIVES

Off-pump coronary surgery reduces transfusions, however, many patients still receive blood. This trial aims to clarify the effect of using a cell saver intraoperatively.

DESIGN

In 60 patients shed blood was collected in the cell saver reservoir intraoperatively; randomization and processing or discharge were performed immediately after surgery.

PRIMARY OUTCOME MEASURES

proportion of patients receiving allogeneic blood, and average number of units per patient.

SECONDARY OUTCOME MEASURES

blood loss, hemoglobin levels, complications, and costs.

RESULTS

Cell saver group versus control group; received transfusions: 17/30 vs. 14/29 (p = 0.28), allogeneic units: median 1 (interquartile range 0 - 2) vs. 2 (IQR 0 - 7) (p = 0.06), intraoperative net blood loss: median 300 ml (IQR 193 - 403) vs. 610 ml (IQR 450 - 928) (p < 0.001). Control group patients had more complications leading to transfusion. Hemoglobin levels and costs were comparable between groups.

CONCLUSIONS

Use of cell saver reduced intraoperative net blood loss and seemed to reduce transfusions by 1 unit per patient, however, this was probably attributable to more complications leading to transfusion in the control group. In the future larger trials are necessary.

[Case of caesarean section using Cell Savers5+ in a patient with the placenta accreta associated with massive hemorrhage]

Placenta accreta which occurs as a complication of total placenta previa is comparatively rare. And the diagnosis of placenta accreta before the caesarean section (C-section) is difficult. We experienced an extremely difficult anesthesia management of placenta accrete because of critical hemorrhage during C-section. We used self-blood collection device Cell Saver5+ (Haemonetics Japan Ltd, Tokyo) for the massive bleeding of 25,500 ml. The Cell Saver could be used to treat life threatening bleeding in C-section without any side effects, although it is thought that the use of the self-blood collection device during C-section had the danger of the amniotic fluid embolism and fetal red cell ontamination. It is necessary to consider using the Cell Saver in the obstetrical operation for life-saving medical treatment in response to unexpected massive bleeding.

[Automatic blood reinfusion in intraabdominal bleedings]

147 patients with polytrauma, complicated by acute large-volume intraabdominal bleeding, were included in the study. Anesthetic regimens and blood loss compensation were retrospectively analyzed. Thus, all patints were divided inti 3 groups: 1st group received only intraoperative blood reinfusion, 2nd group - got auto- and donor blood reinfusion, 3rd group had only donor blood transfusions. Intraoperative autoblood reinfusion allowed an adequate blood loss compensation. The method should be considered a method of choice by acute blood loss treatment during emergency operations in patients with polytrauma.

[Use of a blood recuperating device. Total knee arthroplasty]

The authors evaluate the adoption of a protocol to recuperate blood from drainage during surgery for knee prosthesis. They carried out a prospective study on 19 patients diagnosed with knee arthrosis and who underwent surgery for Total Knee Arthroplasty from September 2006 through June 2007. The medical instrument used was Bellovac, produced by Astral Tech. In the Post anesthesia Reanimation Unit, four patients received a homologous transfusion (27.50%). Prior to the adoption of this protocol, the rate of transfusion was 37%. Hemoglobin during preoperative procedures was not a risk factor for a homologous transfusion. This is associated with the volume drained and reinserted. Patients who received a transfusion had drained 450 cc or more. The study did not record any complication due to the use of the recuperating device. The use of this device made it possible to decrease homologous blood transfusions.

The utility of the perioperative autologous transfusion system OrthoPAT in total hip replacement surgery: a prospective study

BACKGROUND

Total hip replacement (THR) is associated with a significant perioperative blood loss, and 30-50% of these patients receive allogeneic blood transfusion (ABT). We evaluated the clinical utility of washed shed blood (WSB) return to reduce ABT in THR patients.

STUDY DESIGN AND METHODS

Data from 108 consecutive THR patients were prospectively collected. WSB salvage and reinfusion (OrthoPAT) was intended for 60 (Reinfusion group), whereas the remaining 48 patients served as control group. Patients received ABT if haemoglobin <8 g/dl or clinical signs and symptoms of acute anemia.

RESULTS

WSB return was possible in 49 patients (205 +/- 151 ml of erythrocyte/patient), without any clinically relevant incident. Return of WSB decreased both the ABT rate (48 vs. 15%, for control and reinfusion groups, respectively; P = 0.001) and the ABT index (371 +/- 154 ml RBC vs. 53 +/- 117 ml RBC, respectively; P = 0.001), without differences between cemented and uncemented THR. In addition, patients from reinfusion group showed a trend to lower postoperative infection rate (10 vs. 2%, respectively; P = 0.086).

CONCLUSIONS

Perioperative salvage and return of WSB in THR seems to effectively reduce the requirements for ABT. However, for patients with preoperative Hb < 13 g/dl, some additional blood saving method should be associated to WSB return.

Filters in autologous blood retransfusion systems affect the amount of blood cells retransfused in total knee arthroplasty: a pilot study

A pilot study was undertaken to evaluate whether filters integrated in postoperative retransfusion systems affect the amount of blood cells retransfused after total knee arthroplasty. Twenty-two consecutive patients received either the Donor retransfusion system (n=12 patients) or the Bellovac ABT retransfusion system (n=10). Both systems differ with respect to the type of filter, a Pall Lipiguard filter and a Sangopur filter, respectively. At the beginning of the retransfusion, blood samples were taken before and after the filter. The filter of the Donor system significantly decreased the amount of leukocytes and erythrocytes, whereas the filter of the Bellovac system did not. As a result the haemoglobin level of retransfused blood with the Donor system was significantly lower than with the Bellovac system. It can be concluded that the type of filter integrated in two postoperative autologous blood retransfusion systems significantly affected the amount of blood cells retransfused in patients undergoing total knee arthroplasty.

On-line autotransfusion waste calculator

Cell concentrating and washing techniques are widely accepted and believed to be beneficial to cardiac surgery patients. During cell processing, platelets, proteins, and clotting factors are wasted as the plasma is washed away by saline. Beneficial and costly plasma constituents are sacrificed for the sake of removing potentially harmful drugs, debris, and naturally activated cells and chemical mediators. An interactive Microsoft Excel spreadsheet was designed to input patient and autotransfusion system (ATS) reservoir blood values, processed centrifugal bowl data, and hospital allogeneic blood product concentration and cost information. The spreadsheet calculates the number of wasted platelets, grams of protein, and milligrams of fibrinogen. The calculator further estimates the number of units and cost of allogeneic blood products needed to replace the wasted blood components. The simulation allows for variable levels of platelet activation and protein removal during centrifugal cell processing. Specific case scenarios may be simulated with the calculator. If a known volume of residual extracorporeal circuit blood with a known hematocrit, platelet count, and protein concentration is diverted to the ATS reservoir to be processed and washed after bypass, the number of units of fresh frozen plasma, platelet packs, and albumin concentrate needed to replace the wasted proteins and platelets may be calculated. When typical end-bypass patient and blood bank product values are input, the cost to replace the wasted blood components in 1550 mL of residual circuit blood with allogeneic blood products is about US $2097. There are risks and costs associated with replacing the platelets, proteins, and clotting factors wasted during cell washing compared with other techniques such as whole blood ultrafiltration.

Efficacy of cell saver in reducing homologous blood transfusions during OPCAB surgery: a prospective randomized trial

Despite the refinements in surgical technique, rates of homologous blood transfusion (HBT) in cardiac surgery remain high. The adverse effects of blood transfusion are well documented. Retransfusion of shed mediastinal blood reduces the requirement for HBTs during conventional coronary artery bypass grafting. However, some studies have found that autotransfusion leads to bleeding diathesis and paradoxical increase in blood transfusions. Through this prospective randomized trial, we have studied the safety and efficacy of this modality in patients undergoing off-pump coronary artery bypass grafting (OPCAB). Fifty patients enrolled in the study and 49 fulfilled the study criteria. They were randomly divided into group C (cell saver) and group N (non-cell saver). Whereas the cell saver group received processed shed autologous blood and homologous blood if necessary, the non-saver group was transfused homologous blood only. The threshold for transfusion was haemoglobin of 9 g dL(-1) in both the groups. The cell saver group required significantly less number of HBTs (1.6 +/- 1.2 vs. 2.4 +/- 1.3 units). The incidence of re-exploration was zero in both the groups. The mean mediastinal drainage in both the groups was not significantly different (355 +/- 196 vs. 316 +/- 119.8 mL). The number of patients requiring any blood transfusion however was very high. All the patients in the non-saver group and 20 (83%) of the patients in the saver group received homologous blood. During OPCAB surgery, the use of cell saver reduced the requirement for HBT. Its use is not associated with any clinically significant bleeding diathesis.

Improved coagulation and blood conservation in the golden hours after cardiopulmonary bypass

The Hemobag (HB) technique allows the open-heart team to safely concentrate the residual cardiopulmonary bypass (CPB) circuit contents and return a high volume of concentrated clotting factors and blood cells back to the patient as autotransfusion. Hematocrit, platelet count, fibrinogen concentration ([Fib]), prothrombin time (PT), partial thromboplastin time (PTT), and international normalized ratio (INR) were compared between two prospective convenience groups of cardiac surgical patients whose residual circuit blood was processed by the HB (n=10) or by the Cell Saver (CS; n=10) at two times after CPB: (a) after acute normovolemic hemodilution (ANH) infusion and protamine administration and (b) after admission to the intensive care unit (ICU), approximately 1 hour after CPB and HB content infusion. Minimal cell processing was also used in the HB patients to conserve blood. "Golden hours" is defined as the first few hours after CPB and protamine sulfate administration and extend into the ICU, when maintaining hemostasis is vital during cardiac surgery and is the most susceptible period for blood product administration and the opportunity to improve patient outcome. Except for PTT, all parameters changed significantly from the ANH infusion and protamine administration to approximately 1 hour after HB blood infusion and arrival in the ICU. Fibrinogen (p = .048) and hematocrit (p = .046) were significantly higher in the HB group compared with the CS group at the end of the golden hour despite infusion of significantly more allogeneic blood products (p = .070) and more washed red blood cells (RBCs; p = .001) in the CS group. All but one of the HB patients did not receive any allogeneic blood products during the golden hours. Use of the HB technique for salvaging blood is associated with significant increases in the patient's protein and cellular concentrations and lowered coagulation times in the important, first few golden hours after CPB, and except for one patient, without the addition of expensive and precarious allogeneic blood products.

Autotransfusion management during and after cardiopulmonary bypass alters fibrin degradation and transfusion requirements

The coagulation-fibrinolytic profile during cardiopulmonary bypass (CPB) has been widely documented. However, less information is available on the possible persistence of these alterations when autotransfusion is used in management of perioperative blood loss. This study was designed to explore the influence of autotransfusion management on intravascular fibrin degradation and postoperative transfusions. Thirty patients, undergoing elective primary isolated coronary bypass grafting, were randomly allocated either to a control group (group A; n=15) or an intervention group (group B; n=15) in which mediastinal and residual CPB blood was collected and processed by a continuous autotransfusion system before re-infusion. Intravascular fibrin degradation as indicated by D-dimer generation was measured at five specific intervals and corrected for hemodilution. In addition, chest tube drainage and need for homologous blood were monitored. D-dimer generation increased significantly during CPB in group A, from 312 to 633 vs. 291 to 356 ng/mL in group B (p = .001). The unprocessed residual blood (group A) revealed an unequivocal D-dimer elevation, 4131 +/- 1063 vs. 279 +/- 103 ng/mL for the processed residual in group B (p < .001). Consequently, in the first post-CPB period, the intravascular fibrin degradation was significantly elevated in group A compared with group B (p = .001). Twenty hours postoperatively, no significant difference in D-dimer levels was detected between both groups. However, a significant intra-group D-dimer elevation pre- vs. postoperative was noticed from 312 to 828 ng/mL in group A and from 291 to 588 ng/mL in group B (p < .01 for both). Postoperative chest tube drainage was higher in the patients from group A, which also had the highest postoperative D-dimer levels. Patients in group A perceived a higher need for transfusions of red cells suspensions postoperatively. These data clearly indicate that autotransfusion management during and after CPB suppresses early postoperative fibrin degradation.

KEYWORDS

cardiopulmonary bypass, cardiotomy suction, coronary surgery, autotransfusion, fibrin degradation.

Processing of stored packed red blood cells using autotransfusion devices decreases potassium and microaggregates: a prospective, randomized, single-blinded in vitro study

The aim of the study was to compare the potential of autotransfusion devices to reduce non-infectious complications related to transfusion of long-stored packed red blood cells (PRBC; n= 57), such as changes in electrolytes, blood cells and the load of free microaggregates. Following a baseline measurement, a blood pool of three PRBC was divided into three equal volumes and washed with either the Haemonetics Cell Saver (HCS) or the continuous autotransfusion system (C.A.T.S), using the quality (CATS(quality)) and emergency (CATS(emergency)) mode. After the washing procedure, measurements for electrolytes, blood cells and free microaggregates were repeated (n= 19 each). Compared with baseline, the investigated autotransfusion devices reduced the median load of potassium (baseline: 52 mEq L(-1); HCS: 4 mEq L(-1); CATS(quality): 4 mEq L(-1); CATS(emergency): 17 mEq L(-1); each P < 0.001), restored a physiologic electrolyte balance and significantly decreased the load of leucocytes, glucose and protein. Whereas the quantity of microaggregates was not reduced by HCS, CATS(emergency) decreased the load of cell fragments below 7.8 microm (P < 0.05 vs. baseline). Using CATS(quality) decreased the load of cell fragments not only to a diameter below 7.8 microm (P < 0.001 vs. baseline) but also of microaggregates between 7.8 and 17.6 microm (P < 0.05 vs. baseline). In situations where long-stored PRBC have to be transfused, the procedure described here may be feasible to reduce clinically relevant side effects, i.e. hyperkalaemia and microvascular obstruction secondary to free cell fragments. This approach could be especially useful in patients undergoing massive transfusion and/or suffering from renal failure.

Washing of stored red blood cells by an autotransfusion device before transfusion

BACKGROUND AND OBJECTIVES

The use of an autotransfusion device to wash blood of the incision site is increasing. After washing, this blood is retransfused without side effects caused by activated plasma factors and cell release products. This procedure could be extended to washing of donor blood, which may be particularly useful for red blood cells (RBCs) stored for more than 4 weeks that contain high concentrations of free haemoglobin, potassium, lactate and other metabolites. It is not known whether stored RBCs can withstand the cell washing procedure with the use of an autotransfusion device, while keeping their primary functions intact. The objective of this study was to determine the quality of RBCs, after cell washing in comparison to untreated RBCs.

MATERIALS AND METHODS

RBCs were studied in terms of integrity (free haemoglobin), stored energy (2,3-diphosphoglycerate, adenosine triphosphate), metabolites (lactate, potassium) and physical characteristics (osmotic resistance, aggregability, deformability).

RESULTS

After washing, free lactate and potassium were significantly reduced as compared to the levels before washing. The osmotic resistance of RBCs slightly improved, whereas aggregation capacity reduced after washing. Fifteen per cent of haemoglobin was lost during washing. The deformability and free haemoglobin levels remained unchanged.

CONCLUSION

Washing stored blood before transfusion may be of benefit, because the waste products are effectively removed from the stored RBC.

Efficacy, safety and user-friendliness of two devices for postoperative autologous shed red blood cell re-infusion in elective orthopaedic surgery patients: A randomized pilot study

To determine the safety, efficacy and user-friendliness of two different postoperative autologous blood re-infusion systems, an open, randomized, controlled study was performed. Eligible consecutive primary and revision total hip and knee replacement patients were randomized for one of the two systems or for a control group in which shed blood was not re-infused. The nursing staff scored user-friendliness. Patients were monitored after re-infusion. In all three patient groups, a restrictive transfusion trigger was used. Sixty-nine of 70 randomized patients were evaluated. Ease of use, efficacy and safety of both re-infusion systems were comparable. There was no difference in allogeneic blood use between the groups. Thirty per cent of the patients re-infused with autologous blood developed a mainly mild, febrile transfusion reaction. No other adverse reactions were seen. Signs of coagulopathy after re-infusion were not found. In multivariate analysis, autologous re-infusion was an independent factor associated with a shorter hospital stay. Both postoperative autologous blood re-infusion systems were of equal efficacy and safety. The contribution of autologous wound blood re-infusion to reduce allogeneic transfusions must be investigated in a larger study.

[Efficacy of intraoperative apparatus autotransfusion of the blood in revisional endoprosthesis of the hip joint]

Significant blood loss and the methods of its compensation constitute one of the main problems of revisional prosthesis of big joints. Application of a patient's blood constitutes the most available and secure way of the problem solution at the modern stage of surgery evolution. The apparatus autotransfusion of the blood owes prominent place in the system of the blood saving, solely as well as in combination with autodonoring and preoperative hemodilution. In the patients, to whom the revisional prosthesis of the hip joint was performed, using intraoperative apparatus autotransfusion of the blood and the donor's erythrocytes, the red blood indexes were investigated on the stages of operative intervention and postoperative period. Application of apparatuses, such as Cell Saver, constitutes optimal and secure method of the blood oxygentransporting function restoration in the revisional prosthesis of big joints operations.

Randomized Controlled Trial of Pericardial Blood Processing With a Cell-Saving Device on Neurologic Markers in Elderly Patients Undergoing Coronary Artery Bypass Graft Surgery

BACKGROUND

Processing of pericardial shed blood with a cell-saving device was claimed to prevent lipid microembolization and to protect from neurocognitive dysfunction after cardiopulmonary bypass. The present study tested the hypothesis that processing of pericardial shed blood with a cell-saving device during cardiopulmonary bypass would significantly decrease serum levels of protein S100B, and improve brain oxygen saturation and neurologic outcome, all markers of brain injury in elderly patients.

METHODS

Forty patients, 65 years of age and older, undergoing coronary artery bypass graft with cardiopulmonary bypass, were prospectively randomly assigned to processing of pericardial shed blood with a cell-saving device or to conventional use of a standard closed venous reservoir where cardiotomy blood was collected and reinfused through the arterial circuit (control group). Serum in S100B was measured 30 minutes, 4 hours, 24 hours, and 48 hours after surgery. Near-infrared spectroscopy monitoring was performed during the procedure and the National Institutes of Health stroke scale was measured before surgery and at the time of discharge of the hospital.

RESULTS

Patients in the cell-saving device group averaged 72 +/- 3 years of age and underwent 3.1 +/- 0.7 coronary artery grafts with a mean of 62 +/- 20 minutes of cardiopulmonary bypass time. Patients in the control group averaged 75 +/- 4 years of age (p = 0.03) and underwent 3.3 +/- 0.6 coronary artery grafts (p = 0.49) with a mean of 75 +/- 25 minutes of cardiopulmonary bypass time (p = 0.12). The quantity of blood administered from the cell-saving device averaged 281 +/- 162 mL per patient. Serum protein S100B levels averaged 0.06 +/- 0.03 before surgery and 0.51 +/- 0.23 microg/L 30 minutes after surgery in the cell-saving device patients compared with 0.076 +/- 0.04 before surgery (p = 0.32) and 1.48 +/- 0.66 (p < 0.0001) in the control patients. The near-infrared spectroscopy baseline mean value of left and right cortical region was 58% +/- 12% and 55% +/- 7% in the cell-saving device group versus 59% +/- 7% and 53% +/- 6% in the control group (p = 0.67 and 0.36), and no difference occurred over time in each group. The National Institutes of Health stroke score before and after surgery was similar in the two groups. There was one cerebrovascular complication in the control group (1 of 20, 5%) after surgery.

CONCLUSIONS

The difference between the two groups occurred 30 minutes after surgery, at which time serum levels of protein S100B were significantly higher in the control group compared with cell-saving device patients. Although use of the cell-saving device was not associated with higher brain oxygen saturation nor changes in the National Institutes of Health stroke score, it is associated with lesser release of nonspecific markers of brain injury in elderly patients.

A prospective comparison of the platelet sequestration ability of three autotransfusion devices

Although current autotransfusion devices have platelet sequestration capabilities, each has a unique technology to achieve the final platelet product. The purpose of this study was to assess the quality and quantity of platelets sequestered by three different autotransfusion devices. The three commercially available autotransfusion devices evaluated were Fresenius C.A.T.S (closed spiral chamber), Cobe BRAT 2 (Baylor bowl), and Haemonetic Cell Saver 5 (Latham bowl). Platelet sequestration was preformed in the automatic mode following the manufacturer's recommended sequestration protocols. The total number of platelets sequestered, percent recovery, and percent platelet function were assessed. Each device behaved similarly. There was a 2- to 3-fold increase in platelet count compared with baseline with only approximately 50-60% recovery, whereas there was approximately a 10% decrease in platelet function after processing compared with baseline. No statistical difference was noted in platelet function between the respective machines. However, there was a significant loss of platelet function observed with the actual process regardless of autotransfusion device used.

Impact of an autotransfusion system during endoluminal repair of abdominal aortic aneurysms: does it decrease the use of allogeneic blood?

Endoluminal repair of abdominal aortic aneurysms (AAA) is associated with decreased blood loss and transfusion requirements when compared to open AAA repair. We evaluated the use of an intraoperative autotransfusion system during endoluminal exclusion of AAAs. Fifty endoluminal AAA procedures selected at random were reviewed retrospectively. Patients were divided into 4 groups according to their estimated blood loss: Group I, 20 patients (0-500 cc); Group II, 18 patients (501-1,000 cc); Group III, 7 patients (1,001-1,500 cc); and Group IV, 5 patients (1,501-3,400 cc). The average blood loss was 327 cc for Group I, 728 cc for Group II, 1,217 for Group III, and 2,125, for Group IV. The overall blood loss was 834 cc, but 75 per cent was recovered. Hematuria was always present when greater than 1,000 cc of blood was retransfused, but renal function was not affected even with the concomitant administration of radiographic contrast. Only one patient required an autologous blood transfusion. The use of an autotransfusion device is safe, efficacious, and appears to further limit the need for homologous blood transfusion in patients undergoing endoluminal AAA repair.

Particle separation using ultrasound can be used with human shed mediastinal blood

BACKGROUND

Shed mediastinal blood collected by cardiotomy suction has been shown to be a large contributor to lipid microemboli ending up in different organs. The aim of this study was to test the separation efficiency on human shed blood of a new separation method developed to meet this demand.

METHODS

Shed mediastinal blood collected from the pericardial cavity of 13 patients undergoing cardiac surgery with cardiopulmonary bypass was collected. The blood was processed in an eight-channel parallel PARSUS separator, and separation efficiency was determined.

RESULTS

Erythrocyte recovery, in terms of a separation ratio, varied between 68% and 91%. Minor electrolyte changes took place, where levels of sodium increased and levels of potassium and calcium decreased.

CONCLUSION

This study demonstrates that PARSUS technology can be used on human shed mediastinal blood with good separation efficiency. The technology is, thereby, suggested to have future clinical relevance.

[Evaluation of the OrthoPAT autologous transfusion system by experimental models simulating intra- and postoperative blood salvage]

OBJECTIVE

To evaluate the efficacy of the OrthoPAT (Haemonetics) system for blood salvage and for removing chemical or cellular debris, by experimental models simulating intra- and postoperative conditions.

MATERIAL AND METHODS

Blood samples (20%-25% packed red cells) were prepared for the intraoperative model (n=8) and the postoperative model (n=22). Surgical compresses were soaked in some samples (n=5). Other samples were supplemented with hemolyzed blood (n=7). From others cytokines were removed and blood activated with bacterial liposaccharides (n=10) was added. The samples were analyzed before and after processing; tests included detection of free plasma hemoglobin (FPH), potassium ions (K+), glutamic oxalic transaminase (GOT), lactate dehydrogenase (LDH), proteins, and cytokines.

RESULTS

In the intraoperative model 2935 (SD 260) mL of blood was processed. The concentration of packed red cells was 63% and 80% of the red cells were recovered. In the postoperative model 652 (35) mL was processed, the packed red cell concentration was 67% and 81% of the red cells were recovered. Reductions were observed in the concentrations of white blood cells (72%), platelets (88%), GOT and LDH (75%), and proteins and K+ (>95%). Fifty percent of the red cells were recovered in the surgical compresses model. In the hemolysis model, the K+ and FPH concentrations were reduced more than 95%. In the cytokine model, up to 90% of the interleukin 1beta, interleukin 6, and tumor necrosis factor content was removed from the activated blood samples.

CONCLUSIONS

These findings suggest that the OrthoPAT system washes blood and salvages content effectively, recovering 80% of red cells. Moreover, its processing capacity (800-1000 mL x h(-1)) seems adequate for blood replacement in orthopedic surgery.

Quality of thrombin produced from the patient's own plasma using the TPD, a new Thrombin-processing Device

Thrombin derived from bovine sources commonly is used to arrest bleeding during surgical procedures. However, complications such as postoperative hemorrhage can occur because of the development of cross-reactive anti-bovine antibodies that inhibit human coagulation factor V. It would thus be advantageous to develop techniques to generate human thrombin. This study evaluated thrombin produced from human plasma using a new Thrombin-Processing Device (TPD). Plasma was introduced into the TPD, mixed with an ethanol/ CaCl2 reagent, incubated for 1 h, and the harvested thrombin was assayed for activity and the ability to activate platelets by in vitro assays. TPD-produced thrombin activity was found to be 51.8 +/- 12.4 IU/mL (n = 145). TPD-produced thrombin also stimulated P-selectin (CD62) expression (83 +/- 13% of the platelet population) and Annexin V binding (10.3 +/- 2% of the platelet population) on platelets in a similar fashion to commercial thrombin (P-selectin expression: 88 +/- 3%; Annexin-V binding: 11.4 +/- 3%). Compared with CaCl2 and batroxobin, TPD-produced thrombin had a significantly greater ability to activate platelets. TPD-produced thrombin from human plasma has consistent activity and significantly activates platelets and, thus, may have attractive applications such as the production of autologous thrombin for surgical patients.

An economic justification for autologous blood re-infusion in primary total knee replacement surgery

INTRODUCTION

To justify economically the use of autologous blood re-infusion after total knee replacement surgery compared with vacuum drains. To determine if the patients using autologous re-infusion units have a reduced allogenic blood transfusion requirement and hospital stay.

PATIENTS AND METHODS

Prospectively, 50 patients undergoing primary unilateral total knee replacements with autologous re-infusion units were studied. They were matched for age, sex, type of prosthesis and the month in which surgery took place to a second group undergoing the same surgery with vacuum drains. The results for the second group were obtained retrospectively from the notes. The outcome measures were the need for allogenic blood transfusion and length of postoperative hospital stay.

RESULTS

The use of re-infusion units reduced the need for postoperative allogenic blood transfusion from 28% to 4% in total knee replacement surgery. The cost of using re-infusion units was the same as vacuum drains. Overall, the autologous re-infusion patients were discharged 2 days earlier (99% confidence interval).

CONCLUSIONS

Re-infusion units are no more expensive than vacuum drains. In addition, autologous blood has many clinical benefits compared to allogenic blood. Re-infusion may shorten the hospital stay for patients undergoing total knee replacement surgery.