[Comparison of Orth-Evac and Solcotrans Plus devices for the autotransfusion of blood drained after total knee joint arthroplasty]

Surgical wound blood which is ched through drains after total knee replacement surgery with a tourniquet may be returned to the patient using special collecting devices. This study aimed to compare two systems, Orth-Evac and Solcotrans Plus an to assess the safety of the reinfusion of non washed blood cells. It included 30 patients scheduled for total knee replacement surgery, free from tumoral or coagulation disease and allocated randomly in three groups of 10 each: the Orth-Evac group (OGr), the Solcotrans Plus group (SGr) and the Control group (CGr). The devices, not containing an anticoagulant, were connected to the deep suction drains in the operating room, after skin closure and before the tourniquet removal. The salvaged blood was reinfused in the subsequent six hours via a 40 microns filter. The volume of collected blood was measured and homologous blood was added as required, to maintain a hematocrit of 30%. A blood sample was obtained the day before surgery (D - 1), before reinfusion (D0), two hours later (D + 2h), one day later (D + 1), and from the collecting device before reinfusion. The statistical analysis used the Kruskal-Wallis test and Steel-Dwass procedure to confirm the difference between two groups. The three groups did not differ in age, weight, height and gender. The volume of salvaged and autotransfused blood was 925 +/- 156 mL in OGr and 605 +/- 178 mL in SGr respectively, transfusion of homologous blood was required in two patients of OGr, four of SGr and six of CGr. At D + 1, the hematocrit was comparable in all groups (OGr = 28%, SGr = 28.2% and CGr = 28.5%).(ABSTRACT TRUNCATED AT 250 WORDS)

[Autotransfusion, with blood drained from a hemothorax, using the ConstaVac device]

The technique of autotransfusion with blood drained from a haemothorax has been described nearly 80 years ago. The shed blood is easy to collect and is incoagulable. This technique as two indications: lifesaving autotransfusion in the prehospital phase and blood saving and/or transfusional safety at hospital arrival. This prospective study assessed its value as well as the advantages and disadvantages of the ConstaVac system in 30 patients suffering from haemothorax. This apparatus consists of a 800 mL collecting reservoir on a support equipped with an electric aspirator and a battery. The collected blood is transferred into a reinfusion bag while remaining in a closed circuit. The retransfused volume was 685 +/- 430 mL, representing 80% of the collected volume. The retransfusion took place in less than four hours. The patients with an isolated haemothorax did not receive any homologous blood. Only one technical problem occurred, related to the excessive volume of the haemothorax. The shed blood has decreased content of platelets, fibrinogen, and is incoagulable. Moreover, it is hemolyzed. Its hematocrit is lower than the patient's one. On the other hand, the concentration of 2,3 DPG remains normal. These modifications have no detrimental consequences on the patients as long as the autotransfused volume does not exceed two litres. Infectious problems are rare. Handling requires strict asepsis. The ConstaVac system is marketed for postoperative autotransfusion. It is compact, self-contained and very easy to use. It is the only system able of ensuring blood drainage and retransfusion simultaneously, without requiring any opening of the circuit.(ABSTRACT TRUNCATED AT 250 WORDS)

[Is it safe and available to transfuse directly the shed mediastinal blood after cardiac surgery?]

Autotransfusion of the shed mediastinal blood after cardiac operations was performed in 20 cases (ATS group). Safety and efficacy of the autotransfusion were studied comparing with the 10 cases without autotransfusion (control group). A 65.1 +/- 17.1% of bleeding volume within 24 hours after surgery was autotransfused in the ATS group. The ATS group received 1,396 +/- 1,674 ml of the banked blood compared with 780 +/- 1,194 ml for the control group. There was no significant difference between two groups in regard to saving the banked blood. Hematological and biochemical studies after surgery in the ATS and control groups revealed that CPK, BUN and creatinine of the ATS group were significantly higher than those of the control group, although these changes were transitory and trivial. However, prothrombin time of the ATS group was lower than that of control group, so there may be the possibility that this technique itself increases the hemorrhage. Since the cardiotomy filter was obstructed with clots in cases of massive bleeding, shed mediastinal blood may not be fully defibrinogenated in the cases with massive bleeding. These results lead to the following conclusions: autotransfusion of the shed mediastinal blood after cardiac operations is a safe method, but the efficacy of it is doubtful.

Autologous blood recovery. A guide for health care providers

Autologous blood recovery devices have taken on new importance in the effort to conserve finite resources of blood products in the face of ever-growing demand. By incorporating this technology in the vascular, orthopedics, and cardiovascular arena, substantial savings of blood will be realized. The expanded utilization of autologous blood recovery will enable an already burdened blood supply system to continue to provide an adequate source for our patients. It will also help assuage our patients' fears by limiting their exposure to homologous products and the attendant risk of infection by blood-borne pathogens.

[The effect of different autotransfusion procedures on the antibiotic picture. A study on cephalosporin cefamandole]

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.

Intraoperative reinfusion of whole blood using a new autoinfusion device

Aortic aneurysm resection is frequently associated with considerable blood loss and requires transfusion. To minimize complications and cost many institutions use a "cell saving" method that allows reinfusion of the washed red cell fraction of blood suctioned from the operative field. The disadvantages of this technique are that homologous transfusion is regularly required to replace platelets and coagulation factors. Red cell transfusion may also be required when there is rapid major blood loss as the wash cycle may be too long to subject a patient, in a high-risk group for coronary artery disease, to anaemia. A new autoinfusion device anticoagulates blood as it is suctioned from the operative field then filters, defoams, and returns it whole to the patient without a processing time lapse. We successfully used the device in a patient for aortic aneurysm resection to reinfuse two-thirds of his blood volume shed over 80 min. Neither banked red cells nor plasma were used. His haematocrit and coagulation profile remained stable throughout surgery and recovery. The potential complications and cost of homologous transfusion were avoided.

Should the Cell Saver Autotransfusion Device be used routinely in all infrarenal abdominal aortic bypass operations?

PURPOSE

The purpose of this study was to attempt to identify a group of patients undergoing infrarenal aortic bypass in whom blood loss is consistently less than 2 units, making the routine use of autotransfusion devices unnecessary.

METHODS

Four groups of patients were prospectively studied as follows: abdominal aortic aneurysm (AAA) repair with tube graft (n = 21), AAA repair with bifemoral or biiliac bypass (n = 19), and aortobifemoral bypass (AFB) or biiliac bypass for occlusive disease either with Cell Saver Autotransfusion Device (Haemonetics Corp., Braintree, Mass.) (n = 18) or without Cell Saver (n = 18). The latter two groups were randomized on an alternating basis.

RESULTS

The following parameters were obtained on all patients: preoperative hemoglobin values, estimated blood loss, Cell Saver return volumes, intraoperative and postoperative homologous blood transfused, postoperative hemoglobin values on the day of surgery and on postoperative days 1 and 4, complications, and length of hospital stay. In comparing the groups undergoing AFB with Cell Saver and AFB without Cell Saver by the above parameters, we found no statistically significant differences, except for a higher hemoglobin level on postoperative day 1 in the group undergoing AFB with Cell Saver (mean 11.86 vs 10.74, p = 0.02). The estimated blood loss and Cell Saver return volumes were less for those patients undergoing AFB for occlusive disease compared with those undergoing AFB for aneurysmal disease. Interestingly, estimated blood loss and Cell Saver return volumes for patients with AAA with tube graft and patients undergoing AFB with Cell Saver were similar.

CONCLUSIONS

We conclude that routine setup and use of rapid autotransfusion devices may not be necessary in every patient undergoing routine aortofemoral bypass for occlusive disease. Furthermore, the possibility that some patients may undergo AAA repair with tube grafts without use of the Cell Saver may be deserving of further investigation.

What is autologous blood transfusion?

The word autologous is Greek in origin. The definition is exact 'autos' means self and 'logus' means relation. Thus, the meaning is 'related to self'. Autologous blood transfusion, which also is referred to frequently but incorrectly and imprecisely as auto transfusion, designates the reinfusion of blood or blood components to the same individual from whom they were taken. Homologous blood is blood or blood components, from another human donor, taken and stored for later transfusion as required.

[Intraoperative aspiration and reinfusion of autologous blood in resection of abdominal aortic aneurysms with Solcotrans plus]

Quantitative and qualitative assessment of intraoperative aspiration and reinfusion of autologous blood with the Solcotrans was carried out in 11 males (52-79 years) undergoing elective resection of abdominal aortic aneurysms. Hematology, blood chemistry, coagulation parameters and complement activation were studied in the patient's blood at the following time points: preoperatively, before and after heparinisation, after retransfusion of the first and last Solcotrans, 6 and 20 hours postoperatively. In addition the same quality control was performed in the first and last Solcotrans blood. Results (mean values of 11 patients +/- 1 SD): Intraoperatively 2-3 Solcotrans units were salvaged (total 1039 +/- 565 ml) of which 805 +/- 487 ml were retransfused to the patients. As a mean patients required only 1 unit of homologous RBC's (395 +/- 781 ml) intraoperatively. Patient's intraoperative hemoglobin concentration amounted to 10 g/dl or more. Whereas the hemoglobin level in the Solcotrans attained only 8.2 g/dl. Thrombocyte counts (48 +/- 18 x 10(9)/l) and ionized calcium (0.2 +/- 0.4 mmol/l) were significantly depressed when compared to the preoperative patient values (p < 0.05). The protein concentration remained within normal limits in the patient's and in the Solcotrans blood. Complement activation (C4a, C5a [des Arg]) showed a significant increase after initiation of surgery and there was no significant difference between the solco- or patient blood. Whereas plasma free hemoglobin, coagulation and fibrinolysis parameters showed a significant elevation in the Solcotrans blood. In conclusion the solcotrans system offers a fast, efficient and simple method for salvage and retransfusion of intraoperative autologous blood.

[Autologous transfusion of drained blood in hip and knee alloplasty. A prospective controlled study of 56 patients]

Fifty-six patients undergoing hip or knee replacements were randomized to receive autologous drain-blood transfusion or homologous blood transfusion at postoperative need. A reinfusion of 65% of the postoperative drainage blood loss was achieved. The number of homologous blood transfusions fell concomitantly from 2.3 to 0.6 after hip replacement and from 3.3 to 0.3 after knee replacement. No signs of activation of the complement or coagulation systems were found.

The efficacy of postoperative autotransfusion in total joint arthroplasty

Although postoperative blood salvage is used routinely in orthopaedic surgical procedures, little data exists to evaluate this practice. The purpose of this study was to evaluate the effectiveness of the Solcotrans autotransfusion system following elective total joint arthroplasty. This study compared two groups of patients: 59 patients who used the Solcotrans Orthopaedic Drainage/Reinfusion System and 56 patients who used a standard drainage system. Based on the results of the study, the researchers questioned the clinical efficacy and cost-effectiveness of a postoperative wound drainage/reinfusion system in patients after elective total joint arthroplasty.

Platelets in shed mediastinal blood used for postoperative autotransfusion

Ten patients undergoing open-heart surgery received postoperative autotransfusion of shed mediastinal blood collected in the cardiotomy reservoir. The number, function and morphology of the platelets found in the shed blood were investigated. Platelets were counted using an electronic counter compared with light microscopy. Morphology of platelets was studied with electron microscopy. Platelet aggregation was studied using an aggregometer. Dense granule secretion was measured as the extracellular appearance of adenosine triphosphate. Enumeration of platelets in shed blood using the two methods gave different results. Thus, the electronic counter gave a mean platelet count of 62 x 10(9).l-1, while light microscopy revealed only a mean platelet count of 10 x 10(9).l-1. Electron microscopy disclosed few platelets, but numerous cytoplasmatic fragments smaller than or up to the same size as platelets. The platelets found were mostly shape-changed, spheroid, characterized by centralization and loss of alpha-granules and dense bodies, all changes that indicated irreversible platelet activation. The platelets failed to aggregate in response to the presence of thrombin, adenosine diphosphate or collagen, and secretion of adenosine triphosphate was absent. Plasma from the shed blood was not capable of inducing spontaneous aggregation in platelet-rich plasma from healthy donors. These results indicate that infusion of larger volumes of autotransfused blood should be supplemented with platelet concentrates.

[Reduction of the amount of perioperative blood transfusion by autotransfusion techniques in valvular heart surgery]

We used autotransfusion in valvular heart surgery and evaluated its effect on perioperative homologous blood requirements. Methods of autotransfusion we used were intraoperative blood salvage using Cell Saver 4 and retransfusion (IAT), postoperative autotransfusion of shed mediastinal blood (PAT), and hemodilutional autotransfusion (HAT). The patients undergoing valvular heart operations were divided into three groups; group 1 (control group), group 2 (using IAT and PAT group), and group 3 (using IAT, PAT, and HAT group). Perioperative homologous blood requirements significantly decreased in group 3 compared to group 1 and group 2. Operations without homologous blood transfusion significantly increased in number in group 3 compared with group 1. In conclusion, autotransfusions described above were useful blood conservation techniques in valvular heart surgery.

Reinfusion of shed blood after orthopaedic procedures in children and adolescents

A prospective study was done of the results of infusion of drained blood after major procedures on the spine and hip in twenty-six patients. The Solcotrans system was used to salvage drained blood in the first six hours after the operation. Transfusion requirements, blood loss, hematocrit, temperature, prothrombin time, partial prothrombin time, platelet count, results of blood cultures, and levels of factor VIII, factor V,D-dimer, antithrombin III, plasminogen, protein C, and complement C3a des arginine were determined for some or all of the patients. A mean of 375 milliliters of blood from the Solcotrans receptacle was reinfused. All of the cultures were negative. There were no febrile reactions. The mean values for the specimens of the salvaged blood were: hematocrit, 0.20; hemoglobin, seventy-one grams per liter; plasma hemoglobin, 2.36 grams per liter; C3a des arginine, 9.4 x 10(-3) grams per liter; fat particles of less than nine micrometers in diameter, 23,643 per milliliter; and D-dimer, 205 x 10(-3) grams per liter. Studies of blood samples that were collected from patients one to two hours and twelve to eighteen hours after the transfusion showed only slight increases in fibrin split products one hour after the transfusion; these values reverted to normal by eighteen hours. No clinical coagulopathy associated with reinfusion was observed. The reinfusion of unwashed, filtered shed blood that was as much as 15 per cent of the total blood volume proved to be a safe technique after major orthopaedic procedures.

[Solcotrans, a new autotransfusion system]

Thirty-one patients scheduled to undergo aortic reconstruction were studied. 16 had aortic aneurysms and 15 required aortobifemoral grafts. The solcotrans unit comprises a rigid plastic container with an inner lining bag, into which blood is aspirated. When the bag is full (500 ml), the unit is inverted and blood is re-infused through a 40 micron filter. Sixty-three percent of the blood transfused per-operatively and 41% peri-operatively was given with the solcotrans unit. Only minor changes in the coagulation parameters were seen. Blood cultures from ten solcotrans units were all negative. Two patients contracted pneumonia, and one cystitis. We conclude that the solcotrans system is safe to use when two-to four units of blood are transfused. Further studies are required to define its role when multitransfusions of blood are needed.

A feasibility study of a filtration type autotransfusion device

This paper describes a feasibility study of a disposable autotransfusion device for blood salvage during surgery. The goal was to concentrate hemolyzed blood at 20% hematocrit to 50% while reducing the plasma free hemoglobin concentration from 10 to 1.5 g/l. The device should have a total membrane area of less than 0.6 m2 and should be able to process ten 500 ml blood bags. The processing time for each blood bag should not exceed 5 min. The basic idea was to use several polypropylene hollow fibre plasma filters of 0.1 m2 in series with saline addition between them. Since the mean pore size is 0.5 microns, anticoagulant and plasma hemoglobin can pass freely across the membrane and their concentration is reduced by dilution. The process was first modelled using mass balance equations for red blood cells and plasma hemoglobin in order to find the best device configuration (number of filters and dilutions). It was found that a three filter system could theoretically meet the requirements, if the last filter had a larger surface area (0.3 m2). Some experiments permitted us to prove the validity of this model and to define fully the third filtration stage. Finally, it was shown that the treatment of a 500 ml blood bag required three filtration stages (whose surface areas were respectively 0.1, 0.1 and 0.3 m2) and the use of 750 ml of saline solution added between the filters. This configuration also offers the possibility of using a vacuum driving force instead of pumps, so that the device becomes completely disposable.

[The antithrombogenic properties of the vascular wall and platelet aggregation in patients with atherosclerosis of the arteries of the lower extremities following a course of treatment with UV-irradiated autologous blood transfusion]

Sixteen patients with lower limb atherosclerosis (LLAS) stage II-III received autotransfusions of blood irradiated by ultraviolet light. Vascular wall antithrombogenic properties assessed before the treatment in the patients and controls were found deteriorated in LLAS subjects. The cuff test did not affect the antithrombogenic characteristics. The course of autotransfusions produced a clinical improvement and strengthening of the antithrombogenic properties. The cuff test demonstrated a significant decline in platelet aggregation in response to ADP, thrombin, collagen, ristomycin, arachidonic acid; of platelet factor 4, thromboxane B2, beta-thromboglobulin. Concentrations of antithrombin III, plasminogen, prostacyclin rose. The autotransfusions were made on "Izolda" device MD-73 (1 ml of blood per 1 kg b. mass). Irradiation dose 750 J/m2, wave length 254 nm. Platelet aggregation was studied according to Born technique in O'Brien modification. Thromboxane B2, 6-keto-PGF1 alpha, beta-thromboglobulin and TF 4 were measured by radioimmunoassay, antithrombin III and plasminogen by chromogenic substrates.

Some characteristics of blood shed into the Solcotrans postoperative orthopaedic drainage/reinfusion system

OBJECTIVE

To assess the suitability of blood shed into the Solcotrans orthopaedic autotransfusion system as a source of autologous blood for transfusion.

DESIGN

Blood samples were taken from patients after surgery and from shed blood within the Solcotrans units.

SETTING

Surgery was performed at a public hospital.

PATIENTS

All six patients underwent total knee replacements.

MAIN OUTCOME MEASURES

Measurements were made of haemoglobin, haematocrit, platelets, pH, potassium, plasma haemoglobin, fibrinogen, D-dimer, plasminogen activator, thromboplastin and fibrinopeptide A. The non-activated partial thromboplastin time was estimated. Shed blood was compared with homologous whole blood to assess the thrombogenic potential of shed blood in vitro.

RESULTS

The haemoglobin and haematocrit levels of the shed blood were significantly lower than venous blood (P = 0.008). Levels of potassium in shed blood were normal although there was significant haemolysis. Shed blood was depleted of clotting factors, with increased levels of D-dimer (16-128 g/L). Activation of the coagulation pathway within the shed blood was shown by a shortened non-activated partial thromboplastin time (90-120 s), and detectable levels of thromboplastin. Propionibacterium acnes was isolated from one of the units.

CONCLUSION

Reinfusion of large volumes of shed blood should probably be avoided, but use of the Solcotrans orthopaedic transfusion system in conjunction with other autologous transfusion practices can reduce the patient's requirement for homologous blood.

Autotransfusion in aortic surgery: the Haemocell System 350 cell saver

Autotransfusion was performed during elective abdominal aortic reconstruction in ten patients using the recently developed Haemocell System 350. A mean of 60 per cent of total blood loss was salvaged, and during operation each patient was autotransfused 1 unit. Good preservation of cellular components, including platelets, was seen after processing with the device, which uses a vortex mixing filter for cell separation. There was no evidence of coagulopathy; mean free plasma haemoglobin levels were slightly raised (17 mg/dl) and plasma heparin concentration was negligible (0.10 units/ml) 4 h after surgery. A transient drop in plasma fibrinogen levels and the appearance of fibrin degradation products in low concentrations (mean 1.5 mg/l) were seen. Oxyhaemoglobin dissociation curves showed the salvaged red blood cells to have a normal affinity for oxygen. Renal and hepatic function remained unaltered and there were no complications attributable to autotransfusion. The device was easy to handle and a trained operator was not required.

[Effects of postoperative autotransfusion in prosthetic surgery of the hip with the ConstaVac device]

A new device for postoperative autotransfusion (ConstaVac, Stryker) was assessed after total hip replacement in 43 patients, mean age 63 +/- 13 years. Intraoperative blood was administered to 27 patients (63%), autologous blood only in 19, homologous blood only in 6 and both autologous and homologous blood in 2. The blood shed during an average 5-hour postoperative period had an haematocrit of 23 +/- 7% and included only few platelets (72 +/- 83 G.l-1). It did not clot as it contained there was less than 0.1 g.l-1 of fibrinogen and a high concentration of D-dimers. In 30 patients (70%), the amount of blood thus collected exceeded 200 ml. An average of 327 +/- 131 ml were subsequently retransfused to these patients. Postoperative autotransfusion induced a moderate but significant decrease in platelet counts (205 +/- 66 vs. 224 +/- 67 G.l-1, p < 0.02) and fibrinogen concentrations (2.3 +/- 0.7 vs. 2.4 +/- 0.6 g.l-1, p < 0.03), and an increase in circulating D-dimers (p < 0.001). Coagulation tests, free plasma haemoglobin and potassium concentrations were not significantly altered. Since the haematocrit of the blood lost was lower than that of the patients', the haematocrit did not increase significantly. Posttransfusion shivering occurred in two patients (7%). Bacteriological cultures of the lost blood and of venous samples obtained after postoperative autotransfusion remained sterile. Postoperative autotransfusion is a simple technique with few side-effects, which might be safely associated with other methods used to decrease the rate of homologous blood transfusion.

Laboratory evaluation of a low prime closed-circuit cardiopulmonary bypass system

We have explored the potential advantages of a low prime closed-circuit cardiopulmonary bypass (CPB) system using a non-human primate model. Although manufacturers have reduced priming volumes in individual CPB components, the standard circuit volume remains high because of the tubing diameter and length necessary for gravity drainage. By replacing gravity drainage with the negative pressure generated by a centrifugal pump, we can realize significant tubing volume reduction. Closed-circuit bypass was conducted on 13 baboons ranging from 5-15 kg. The circuit consisted of a centrifugal pump, a hollow fiber oxygenator, and 1/4" arterial and venous tubing. The design of the circuit included the capacity to remove a limited amount of venous air. Circulatory arrest during deep hypothermia with volume displacement into a reservoir was also accomplished with this circuit. The potential benefits of this low prime closed-circuit bypass system include blood conservation and reduction in blood surface area contact. The future safe clinical use of this type of closed-circuit bypass for routine open heart surgery will depend upon the incorporation of a device in the venous line to remove air. This is the greatest threat to patient safety in a closed circuit system and its use for open chest surgery must wait until an efficient venous air elimination device is available.

Heparin removal in three intraoperative blood savers in cardiac surgery

The aim of the study was to compare the residual heparin in the composition of autologous blood retransfusion units harvested during cardiac surgery under extra-corporeal circulation with three different intraoperative autologous blood savers. In this institutionally approved study, thirty patients undergoing CABG were randomly assigned to three groups according to the intraoperative blood saver used during the procedure: {HAEMONETICS Cell Saver IV (n=10)--DIDECO/SHILEY STAT (n=11)--BRAT 250 (n=9)}. Anaesthesia and conduct of bypass were identical for all patients. The initial heparin dose was 300IU-kg -1 and was supplemented to maintain an activated coagulation time over 480s. The harvested blood was processed according to the procedure defined by each equipment manufacturer. The biological study was performed on the first blood sediments sampled before administering protamine to the patient. Blood cell count, residual heparinemia assessed by its anti-Xa activity using an amidolytic method {STACHROM HEPARIN--DIAGNOSTICA STAGO}, and weight of the blood sediment proteins were determined. Demographic data did not differ between groups. Despite a slight but significant difference between groups, the three devices provided virtual elimination of heparin. The total protein content was significantly higher in the BRAT 250 group. There was a highly significant positive correlation between the anti-Xa activity and total protein content. Haematologic data were within clinically acceptable ranges.

Cardiotomy suction versus red cell spinning during repair of descending thoracic aortic aneurysms

Two consecutive series of patients undergoing repair of descending thoracic and thoracoabdominal aortic aneurysms with partial cardiopulmonary bypass and low systemic heparinization (activated coagulation time: ACT greater than 180 sec) for proximal unloading and distal protection were analyzed. During the surgical procedures, thoracic shed blood was recovered either with a red cell spinning autotransfusion device (n=10) or two pump suckers and Duraflo II heparin surface coated cardiotomy reservoirs (n=10). There were 5/10 acute lesions and 1/10 ruptures for the autotransfusion group versus 5/10 acute lesions and 2/10 ruptures for the cardiotomy group (NS). Extension of aortic resection (range 1-8) was 3.6+/-1.2 for autotransfusion versus 3.5+/-1.4 for cardiotomy suction (NS). Mean number of reimplanted patches for intercostal and visceral reperfusion was 0.3+/-0.6 for autotransfusion versus 0.6+/-1.0 for cardiotomy (NS). Perfusion time was 41+/-17 min for autotransfusion versus 60+/-19 min for cardiotomy (p less than 0.05) and cross clamp time was 33+/-14 min for autotransfusion versus 43+/-17 min for cardiotomy (p less than 0.01). Total heparin dose was for 9500+/-2100 IU for autotransfusion versus 9800+/-1300 IU for cardiotomy (NS). The mean of the lowest ACTs measured during perfusion was 281+/-121 sec for autotransfusion versus 258+/-58 sec for cardiotomy (NS). The total protamine dose given was 7800+/-2100 IU for autotransfusion versus 9700+/-1900 IU for cardiotomy (p less than 0.05). The volume of washed red cells prepared was 3186+/-1318 ml for autotransfusion versus 0 for cardiotomy (p less than 0.05).(ABSTRACT TRUNCATED AT 250 WORDS)

A controlled trial of intra-operative autologous transfusion in cardiothoracic surgery measuring effect on transfusion requirements and clinical outcome

We carried out a prospective, controlled trial of intra-operative autologous transfusion (IOAT) in cardiac surgery using the Haemonetics Cellsaver 4, to determine the effects on transfusion requirements and early clinical outcome. Intra-operative autologous transfusion in unselected patients resulted in a reduction in the use of red cells in patients undergoing first-time operations (IOAT median 3 units, controls median 4 units, P = 0.0023), with no difference in the use of other blood products. Post-operative haemoglobin was higher in IOAT patients (IOAT 11.6 g/dl +/- 1.1 versus controls 11.2 g/dl +/- 0.98, P < 0.001). There is therefore the potential for a further reduction in homologous blood use in the IOAT group. There was no difference in early clinical outcome in the two groups; in particular the incidence of coagulopathies was not influenced by IOAT. The routine use of IOAT would add substantially to the cost of these operations. The decision to use it must therefore be based on an assessment of the value of the reduction in risk to the patient achieved by a small reduction in homologous donor exposures.