Apparent coagulopathy caused by infusion of shed mediastinal blood and its prevention by washing of the infusate

Direct Reinfusion of Unwashed Shed Autologous Blood During Thoracoabdominal Aortic Aneurysm Repair: A Retrospective Analysis

BACKGROUND

This study's purpose was to assess whether larger volumes of reinfused unwashed shed autologous blood (SAB) were associated with adverse events within 30 days for patients undergoing open thoracoabdominal aortic aneurysm (TAAA) repair. During TAAA repair, our institution uses a system wherein SAB is filtered, but not washed or centrifuged, and then returned to the patient via a rapid-infusion device. By reinfusing SAB, the system preserves the patient's autologous whole blood and may reduce the number of allogenic transfusions required during TAAA repair, but the end-organ effects of reinfusing unwashed SAB have not been extensively evaluated.

METHODS

Using a prospectively maintained database, we retrospectively analyzed data from 972 consecutive patients who underwent open TAAA repair at our institution from 2007 to 2021 and who received SAB. Multivariable logistic regressions were performed to assess whether SAB reinfusion volume was associated with a composite outcome of adverse events, as well as operative mortality, a composite of cardiac complications, a composite of pulmonary complications, or persistent paraplegia, stroke, or postoperative renal failure.

RESULTS

Among the cohort of 972 patients, the median volume of reinfused SAB was 4159 mL (quartile1-quartile3 [Q1-Q3]: 2524-6790 mL). Greater reinfusion volumes of unwashed SAB were not associated with greater odds of composite adverse events (odds ratio [OR], 1.02 per 1000 mL increase, 97.5% confidence interval [CI], 0.94-1.09, P = .624), nor with any individual outcome-operative mortality (OR, 1.02 per 1000 mL increase, 97.5% CI, 0.93-1.12, P = .617), a composite of cardiac complications (OR, 0.98 per 1000 mL increase, 97.5% CI, 0.93-1.04, P = .447), a composite of pulmonary complications (OR, 1.00 per 1000 mL increase, 97.5% CI, 0.94-1.06, P = .963), renal failure necessitating hemodialysis (OR, 1.01 per 1000 mL increase, 97.5% CI, 0.92-1.11, P = .821), persistent paraplegia (OR, 0.97 per 1000 mL increase, 97.5% CI, 0.84-1.13, P = .676), persistent stroke (OR, 0.85 per 1000 mL increase, 97.5% CI, 0.70-1.04, P = .070), or reoperation to control bleeding (OR, 0.99, 97.5% CI, 0.87-1.13, P = .900)-when adjusted for confounders.

CONCLUSIONS

For patients undergoing open TAAA repair, larger reinfusion volumes of unwashed SAB were not associated with greater odds of major early postoperative complications.

Direct autotransfusion following emergency pericardiocentesis in patients undergoing cardiac electrophysiology procedures

INTRODUCTION

Acute hemopericardium during cardiac electrophysiology (EP) procedures may result in significant blood loss and is the most common cause of procedure-related death. Matched allogeneic blood is often not immediately available. The feasibility and safety of direct autotransfusion in cardiac electrophysiology patients requiring emergency pericardiocentesis is unknown.

METHODS

We retrospectively analyzed records of patients undergoing EP procedures at a single, tertiary care medical center who had procedure-related acute hemopericardium requiring emergency pericardiocentesis during a 3-year period. Procedure details, transfusion volumes, and clinical outcomes of patients who received direct autotransfusion of aspirated pericardial blood via a femoral venous sheath were compared to those of patients who did not receive direct autotransfusion.

RESULTS

During the study period, 10 patients received direct autotransfusion (group 1) and outcomes were compared with those of 14 control patients who did not receive direct autotransfusion (group 2). The volume of aspirated pericardial blood was similar in groups 1 and 2 (1.6 ± 0.7 L vs 1.3 ± 1.0 L, respectively; P = .52). Amongst patients with aspirated volumes <1 L, group 1 patients (n = 4) were less likely than group 2 patients (n = 8) to require allotransfusion (0% vs 75%, P = .02). Amongst patients with aspirated volume ≥1 L, group 1 patients (n = 6) required fewer units of red cell allotransfusion than group 2 patients (n = 6) (1.5 ± 0.8 units vs 4.3 ± 2.0 units, P = .01). No procedural complications related to direct autotransfusion occurred.

CONCLUSIONS

Direct autotransfusion following emergency pericardiocentesis during electrophysiology procedures requiring systemic anticoagulation is feasible and safe. The utilization of direct autotransfusion may eliminate or reduce the need for allotransfusion.

Washing and filtering of cell-salvaged blood - does it make autotransfusion safer?

Autologous transfusion was first performed in the late 1800s, but it was not until the 1970s that devices were developed that enabled widespread adoption of the practice. Unwashed salvaged blood contains thrombogenic products, cell breakdown products and plasma proteins, and gross chemical, cellular and physical contaminants. Washing and filtering of salvaged blood is routinely performed to remove or reduce these elements. In this paper we review the clinical data supporting the need for washing and filtering of salvaged blood.

Transfusion of shed mediastinal blood reduces the use of allogenic blood transfusion without increasing complications

BACKGROUND

Reduced use of allogenic blood components is a key issue in cardiac surgery. Several methods to conserve blood have been used; reinfusion of shed mediastinal blood (RSMB) has found widespread acceptance, but the efficacy and safety are still debated. The purpose of this study was to evaluate the effects of RSMB on the use of allogenic blood components and selected complications.

MATERIAL AND METHODS

Six hundred and twenty-three consecutive cardiac surgery patients in three successive periods, of whom patients in the middle period did not receive RSMB due to manufacturer delivery problems, were evaluated. Patients and procedures were characterized by EuroSCORE. Prospective collected data were: units of transfused allogenic blood, fresh frozen plasma (FFP) and platelets, postoperative blood loss and postoperative complications such as dialysis, re-operation due to bleeding, sternal infection and stroke. Length of stay in ICU was used as a general indicator of perioperative complications.

RESULTS

The number of patients receiving allogenic blood in periods with RSMB was significantly lower (36.5% versus 54.9%, p<0.005), while no difference was seen in FFP and platelets. The average number of transfused blood units was lower in patients receiving RSMB (2.07 versus 3.41, p=0.029), while FFP (1.34 versus 2.01, p=0.11) and platelets (0.58 versus 0.95, p=0.05) were not statistically significantly different. Postoperative bleeding was lower (759 versus 967 ml, p=0.032) in the periods with RSMB.

CONCLUSION

Patients receiving RSMB were less transfused with allogenic blood and had less postoperative drainage, while the frequency of observed postoperative complications was not different from patients who did not receive RSMB.

Perioperative blood transfusion: the role of allogenous and autologous transfusions, and pharmacological agents

The decision to transfuse patients perioperatively is made on an individual basis and should consider factors such as duration and severity of anaemia, symptoms, physiological parameters and comorbidities. Autologous blood transfusion has the benefit of avoiding some of the immunological and infective complications associated with allogenic blood transfusion. Pharmacological agents as well as anaesthetic and surgical techniques have a role in avoiding the need for blood transfusion.

Postoperative Care of the Cardiac Surgical Patient

The subspecialty of interventional cardiology began in 1977. Since then, the discipline of interventional cardiology has matured rapidly, particularly with regards to ischemic heart disease. As a result, more patients are undergoing percutaneous catheter interventional therapy for ischemic heart disease and fewer patients are undergoing surgical myocardial revascularization. Those patients referred for surgical revascularization are generally older and have more complex problems. Furthermore, as the population ages more patients are referred to surgery for valvular heart disease. The result of these changes is a population of surgical patients older and sicker than previously treated.

Research on coagulation of unwashed shed blood after total knee replacement in Chinese patients

To evaluate quality of unwashed but filtered wound shed blood through ConstaVac blood conservation system (Stryker Company) after total knee replacement, we selected 30 patients who underwent total knee replacement consecutively from July 2003 to July 2004 and received retransfusion of wound shed blood. Pre- and postoperative coagulative factors of peripheral vein blood and wound shed blood were measured, such as fibrinogen, AT-III, D-dimer, plasminogen, and PT, APTT were also measured. No clinical evidence of coagulation and DIC appeared in these patients. There is significant change of coagulative factors in unwashed but filtered wound shed blood and it may cause a potential risk of coagulopathy to retransfuse wound shed blood, but retransfusion of unwashed but filtered shed blood appeared to be relative safe clinically.

Coagulation Disorders and Blood Product Use in Patients Undergoing Thoracoabdominal Aortic Aneurysm Repair

Repair of thoracoabdominal aortic aneurysms (TAAA) is associated with major blood loss, often exceeding the patient's intravascular volume, and complex intraoperative and postoperative coagulopathies necessitating large-volume transfusion of blood products. Abnormalities sufficient to cause thrombocytopenia or clinically important prolongation of clotting parameters are rarely present before surgery in elective aneurysms but are more common with ruptured aneurysms. The finding of intraoperative and postoperative deficiencies of clotting factors, along with thrombin generation and activation of the thrombolytic system, is reflective of massive blood losses, visceral ischemia, and massive transfusions. An aggressive strategy of transfusion of blood products is critical to the prevention of clinically significant coagulopathy during surgery. Adjuncts to reduce blood losses and blood product use include low-dose aprotinin or epsilon -aminocaproic acid, intraoperative blood salvaging, and acute normovolemic hemodilution. In TAAA repair, an average blood loss of 5000 to 6000 mL and average transfusion of allogeneic blood products of 50 to 60 U are to be anticipated.

Safety and efficacy of methods for reducing perioperative allogeneic transfusion: a critical review of the literature

A number of pharmacologic and nonpharmacologic technologies are in current use to minimize perioperative homologous blood use. Clinical trials, many of them randomized controlled trials, have been done evaluating these approaches and have demonstrated their efficacy. However, data on safety has relied mostly on case reports, uncontrolled studies, and, for the pharmacologic agents, extrapolation from the nonsurgical setting. In this review I analyze the data from the randomized trials and the lower-level evidence studies to provide the best estimates in safety with these alternatives. In general, these alternatives are safe with proper dosing and monitoring of effects. With aprotinin, the primary concern is anaphylaxis, and this predominantly with re-exposure. With aprotinin and with the anti-fibrinolytics, increased venous thromboembolic risk has not been a consistent finding. Tranexamic acid use intraoperatively is advantageous, but postoperative use appears to have no advantage and may be associated with renal dysfunction. DDAVP is low-risk, provided it is not overused, which can induce hyponatremia. Autologous predonation probably has similar risks as homologous blood with respect to transfusion errors and bacterial infection. As with most medical interventions, we must be vigilant to prevent human error.

Levels of inflammatory markers in the blood processed by autotransfusion devices during cardiac surgery associated with cardiopulmonary bypass circuit

Intraoperative blood salvage devices allowing a reinfusion of red blood cells (RBCs) after processing of shed blood and stagnant blood in the mediastinal cavity are more and more used to reduce homologous blood requirements in cardiac surgery with cardiopulmonary bypass (CPB). As the proinflammatory activity of the shed blood also contributes to morbidity during CPB, we conducted a prospective study in order to examine the quality of autologous blood before and after processing with five different devices [BRAT2, Sequestra, Compact Advanced, Cell Saver 5 (CS5), Continuous Autologous Transfusion System (CATS)]. All systems resulted in an excellent haemoconcentration, ranging from 53.7% (Compact) to 68.9% (CATS). The concentrations and elimination rates of several inflammatory markers [IL-1beta, IL-2, IL-8, TNFalpha, myeloperoxidase (MPO), elastase] were examined. Except for the Sequestra, an important increase in concentration of IL-1beta (between 30% and 220%) has been observed after processing with each device. In contrast, the attenuation rate of IL-6 and TNFalpha (95%) was optimal for all investigated blood salvages systems. Regarding IL-8, only the CATS and CS5 systems were able to attenuate this biological parameter with an excellent efficacy. The rate of attenuation in MPO and elastase, as markers of leukocyte activation, was higher than 80% for all devices. In conclusion, the different RBC washing systems tested in this study resulted in a significant attenuation of the inflammatory response. Increased levels of IL-1beta after processing remained, however, unclear. According to the type of protocol, based on inlet haematocrit, fill and wash speeds, and wash volumes, small variations in reducing the inflammatory response have been observed from one device to another.

Activation of plasma coagulation by retransfusion of unwashed drainage blood after hip joint arthroplasty: a prospective study

Twelve patients undergoing cementless hip joint arthroplasty were retransfused with unwashed drainage blood collected postoperatively. Global coagulation parameters, coagulation factors (factor V:C, factor VIII:C, activated factor XII, and factor XIII) and markers of thrombin generation (F1+2 Fibrin split products, thrombin-antithrombin complexes), fibrin generation (fibrinogen and fibrin degradation products), and fibrinolysis (D-dimers, thrombin degradation products, plasminogen) were determined. High levels of factor XIIa, thrombin and fibrin generation markers, and markers of fibrinolysis were present in the shed blood. After retransfusion (mean, 433 mL), increased levels of these markers together with decreased values for factor XIII and plasminogen were indicative of renewed clot formation and fibrinolysis in the circulation. These changes were highly significant compared with preretransfusion values. The unwashed drainage blood contained high levels of procoagulation material and induced an activation of the plasma coagulation pathway with renewed clot formation and fibrinolysis in the patients.

Fibrinolytic activity and postoperative salvaged untreated blood for autologous transfusion in major orthopaedic surgery

OBJECTIVE

To evaluate the fibrinolytic activity in a closed surgical wound, in postoperatively drained blood, and during autologous transfusion.

DESIGN

Prospective study.

SETTING

National hospital, Norway.

PATIENTS

9 patients operated on for thoracic scoliosis.

MAIN OUTCOME MEASURE

Concentrations of plasmin/antiplasmin (PAP), alpha2-antiplasmin, and D-dimers in drained, arterial, and mixed venous blood before, during, and after infusion of 10 ml/kg body weight of postoperatively drained, untreated blood.

RESULTS

In drained blood the concentration of alpha2-antiplasmin was 31% of the preoperative arterial control value. Together with the increased concentrations of PAP to 18076 microg/L and D-dimers to 126 mg/L, this indicates extensive fibrinolytic activity in the closed wound. The postoperative autologous transfusion of drained, untreated blood increased the concentration of PAP from 507 to 2453 microg/L and of D-dimer from 0.7 mg/L to 15.3 mg/L in systemic blood.

CONCLUSION

The systemic concentration of fibrin(ogen) degradation products, indicated by D-dimers, after recirculation of drained, untreated blood might impair coagulation. The extensive activation of plasmin might exhaust available alpha2-antiplasmin in the wound and result in postoperative rebleeding.

The effect of postoperative normovolaemic anaemia and autotransfusion on blood saving after internal mammary artery bypass surgery

The efficacy of two blood conservation techniques in decreasing and in preventing the use of homologous blood products was retrospectively studied in 150 patients undergoing internal mammary artery bypass surgery. Patients were matched according to prebypass blood haemoglobin (Hb) content and body surface area and were allocated to one of three groups: in the patients of group 1 (n = 50), normovolaemic anaemia (NA) was accepted postoperatively (haematocrit [Hct] was accepted to a minimum level of 25%); the patients of group 2 (n = 50) were treated with postoperative autotransfusion (AT) of mediastinal shed blood and acceptance of NA. Group 3 (n = 50) contained control patients, not treated with NA or with AT (Hct was accepted to a minimum level of 30%). Patients of group 1 required 3.0 +/- 0.3 units of homologous blood products, but the patients of groups 2 and 3 received significantly more (p less than 0.01) units: 3.9 +/- 0.2 and 4.5 +/- 0.3 units. No donor blood products were needed in 36%, 9% and 5% of the patients in groups 1, 2 and 3 respectively. The net postoperative blood loss was similar in the groups: 1229 +/- 92 ml in group 1, 1098 +/- 74 ml in group 2 and 1243 +/- 72 ml in group 3. However, total blood loss (1982 +/- 135 ml), including the retransfused part (954 +/- 89 ml), was significantly larger (p less than 0.01) in group 2, than in groups 1 and 3.(ABSTRACT TRUNCATED AT 250 WORDS)

Formation of complement split products and proinflammatory cytokines by reinfusion of shed autologous blood

1. The purpose of this study was to determine whether shed autologous blood collected postoperatively contains complement split products (C3a and SC5b-9) and proinflammatory cytokines (TNF-alpha, IL-1beta, IL-6 and IL-8) and whether transfusion of shed blood increases the concentrations of inflammatory mediators in the circulation. 2. Twenty consecutive patients undergoing total hip replacement surgery under spinal anaesthesia were studied. The patients were transfused with whole blood collected postoperatively. 3. The median volume shed blood returned to the patients was 350 ml (25-75% range = 300-450). Before transfusion of shed blood was filtered using a 40 microm filter (Solcotrans). Samples for complement and cytokine determinations were drawn from the collected blood. 4. Venous blood samples were drawn 1 min before transfusion, 1 and 60 min after completed transfusion. High concentrations of C3a, SC5b-9, TNF-alpha, IL-1beta, IL-6 and IL-8 were found in shed blood. The concentrations were higher than the circulating levels (P < 0.05). The filtration procedure did not significantly reduce the concentrations. 5. Transfusion of the shed blood did not significantly alter the circulating concentrations of C3a, SC5b-9, TNF-alpha, IL-1beta, and IL-8. The plasma concentrations of IL-6 were increased both 1 and 60 min after completed transfusion compared to before (P < 0.05). 6. This study shows that whole blood collected from a surgical wound contains large concentrations of complement split products and proinflammatory cytokines. Transfusion of shed blood leads to elevated plasma levels of IL-6.

[Blood conservation effect and safety of shed mediastinal blood autotransfusion after cardiac surgery]

Autotransfusion of shed mediastinal blood after cardiac surgery has been used to reduce risks related to homologous blood transfusions. To document the efficacy and safety of autotransfusion, we compared clinical findings of 80 patients receiving shed mediastinal blood (autotransfusion group) with those of the control group of 52 patients. The amount of the autotransfusion was limited to 800 ml, given the potentially harmful effects of shed blood transfusion. The mean transfused shed volume was 314 +/- 236 ml (S.D.). The serum levels of FDP-E, D-dimer and TAT after autotransfusion were higher in the autotransfusion group than in the control group (p = 0.01, p = 0.0004, p = 0.001, respectively). However, postoperative blood loss and the rate of reexploration for bleeding were similar in the two groups. The patients receiving blood products were fewer in the autotransfusion group than those in the control group (21% vs 44%; p = 0.005). Autotransfusion did not increase postoperative complications, including infection. Thus, although autotransfusion of mediastinal shed blood has the potential to affect hemostasis, unless the amount of autotransfusion exceeds 800 ml, it appears that this method is clinically safe and effective as a mean of blood conservation.

Removal of activated complement from shed blood: comparison of high- and low-dilutional haemofiltration

BACKGROUND

Perioperative blood salvage is associated with release of inflammatory mediators. Depending on type of processing, the complement system is activated to some extent in the final blood product. The aim of the present study was to evaluate a haemofiltration technique concerning complement system activation and whether the volume of added saline will have an influence on the elimination of activated complement during processing.

METHODS

Sixteen patients undergoing total hip arthroplasty received wound blood salvaged intraoperatively with a haemofiltration technique. Saline was added to the reservoir for washing in a ratio of 1:1 or 5:1 of estimated blood volume. Samples for determination of the anaphylatoxins C3a and C5a, and the terminal SC5b-9 complement complex (TCC) were drawn from the patients, the collected blood, the ultrafiltrate and the processed blood.

RESULTS

Increased concentrations of C3a, C5a and TCC were found in aspirated and processed blood. Haemofiltration did not reduce the concentrations of these factors, except that of C3a in the group where saline was added in a ratio of 5:1. There were no increased concentrations of C3a, C5a or TCC in the patient plasma after reinfusion. No differences in blood pressure, heart rate, pH, arterial oxygen tension, arterial carbon dioxide tension, or base excess were found in association with reinfusion of the blood.

CONCLUSION

Collected shed blood washed through haemofiltration contained moderately elevated concentrations of C3a, C5a and TCC. Reinfusion of the blood neither led to increased systemic concentrations of complement activation products, nor to disturbances in haemodynamic or biochemical parameters.

Isolyte S, a physiologic multielectrolyte solution, is preferable to normal saline to wash cell saver salvaged blood: conclusions from a prospective, randomized study in a canine model

OBJECTIVES

The purpose of this study is to compare normal saline with Isolyte S as the wash solutions during high-volume cell saver autologous blood transfusion. Normal saline, the standard wash solution in cell saver autologous blood transfusion, is associated with acid-base and electrolyte derangements. Isolyte S is a physiologic, balanced multielectrolyte crystalloid solution that approximates the electrolyte content of plasma.

DESIGN

Open-label, prospective, randomized study.

SETTING

Research laboratory in a Department of Veterans Affairs medical center.

SUBJECTS

Fourteen mongrel dogs, weighing 22 to 23 kg each.

INTERVENTIONS

Fourteen mongrel dogs were prospectively randomized to receive normal saline (n = 7) or Isolyte S (n = 7). Animals were anesthetized, received heparin for anticoagulation, and underwent 18 cycles of cell saver autotransfusion. In each cycle, 125 mL of blood was arterially withdrawn, and washed with either normal saline (mEq/L) (sodium 154, chloride 154) or Isolyte S (mEq/L) (sodium 141, potassium 5, magnesium 3, chloride 98, phosphate 1, acetate 28, and gluconate 23). The washed blood was retransfused.

MEASUREMENTS AND MAIN RESULTS

Acid-base and electrolyte analyses were performed throughout the study on the systemic blood of each group and compared. By the end of the study, the Isolyte S group had a normal pH and an increased bicarbonate concentration (mEq/L: normal values 24 to 32; normal saline 9.0 +/- 1.9 vs. Isolyte S 13.2 +/- 3.0 [p < .01]) and an increased magnesium concentration (mg/dL: normal values 1.6 to 2.4; normal saline 1.6 +/- 0.2 vs. Isolyte S 2.2 +/- 0.2 [p < .0001]). Additionally, the Isolyte S group had a lower chloride concentration (mEq/L: normal values 95 to 110; normal saline 130 +/- 9 vs. Isolyte S 117 +/- 7 [p < .02]) and a lower potassium concentration (mEq/L: normal values 3.5 to 5.0; normal saline 4.4 +/- 0.5 vs. Isolyte S 3.7 +/- 0.3 [p < .01]). There were no significant differences between normal saline or Isolyte S in the values of PCO2, lactic acid, sodium, total and ionized calcium, inorganic phosphorus, total protein, albumin, hemoglobin, and hematocrit.

CONCLUSIONS

Fewer systemic acid-base and electrolyte derangements were observed when blood was washed with Isolyte S. Differences between the normal saline and Isolyte S groups are ascribed primarily to the constituents of the wash solution. We conclude that Isolyte S, a physiologic, balanced, multielectrolyte solution, should be considered as the wash solution in high-volume autologous cell saver blood processing and transfusion.

Does heparin coating improve biocompatibility? A study on complement, blood cells and postoperative morbidity during cardiac surgery

To evaluate whether the effect of heparin coating the extracorporeal circuit resulted in differences in patient outcome and haemostatic alteration, 24 patients undergoing elective, isolated coronary artery bypass were randomized prospectively to cardiopulmonary bypass (CPB) with heparin-coated circuits (group H, n = 12) or uncoated circuits (group C, n = 12). The technique of CPB, heparinization and its reversal were the same in both groups. We studied complement status (C3d, C3, C3d/C3, C4 and C-function), white blood cell counts with differentiation and the postoperative morbidity. The results confirmed that CPB activates complement and increases neutrophils in both the H and C groups. A significantly lower level of leucocytosis was seen in group H compared to the C group (p < 0.05). The complement function via the classical pathway (C-function), expressed as a percentage of the function of a reference serum pool (the values of normal sera were 75-125%), was significantly reduced in both heparin-coated and uncoated circuits (p < 0.05). There was no significant intergroup difference regarding C3, C3d/C3, C4 and C-function during the study period. A lower frequency of postoperative morbidity was present in the H group. We conclude that heparin-coated surfaces elicit less leucocytosis and decrease postoperative morbidity in patients undergoing cardiac surgery but do not cause a significant difference regarding activation of the complement system as reported by many other investigators.

Complement activation during storage of whole blood, red cells, plasma, and buffy coat

BACKGROUND

The process of separating whole blood into components and the storage of blood components may cause the release of toxic metabolites from the complement cascade. The aim of this study was to determine whether the storage of blood components leads to the activation of the complement cascade and the release of anaphylatoxins.

STUDY DESIGN AND METHODS

Blood from 12 healthy volunteers was collected and stored either as whole blood or as components: red cells in saline-adenine-glucose-mannitol solution, plasma, and buffy coat. The concentrations of anaphylatoxins and other complement proteins in the various blood components were intermittently analyzed during a 5-week storage period.

RESULTS

Increasing levels of anaphylatoxins were demonstrated during the storage of whole blood and plasma. Elevated concentrations of the anaphylatoxins C3a and C5a were observed during the storage of whole blood. Increased C5a levels were observed after 7 days of storage. High concentrations of C3a were found in plasma after 14 days of storage. Low or non-detectable levels of C3a; C5a, and other complement components were found in red cells stores in saline-adenine-glucose-mannitol solution.

CONCLUSION

The study demonstrated activation of complement during the storage of whole blood and plasma but not in red cells in storage solution. The transfusion of larger volumes of stored whole blood or plasma may contribute to the risk of development of organ dysfunction. Therefore, it is advisable to use red cells in storage solution.

Fatal air embolism due to perioperative blood recovery

This study was initiated to investigate the incidence of acute mortality from air embolism associated with perioperative blood recovery and the causative factors and common characteristics of such fatalities. All facilities providing transfusion services in New York State are required to report severe adverse reactions to, and the total number of, transfusion and blood recovery procedures performed. Relevant data for the period from January 1990 to June 1995 were tabulated. During this time, 127,586 perioperative blood recovery procedures were performed, and 8,955,619 conventional blood components were transfused. The frequency of fatal air embolism after readministration of recovered blood was approximately 1:30,000-1:38,000; none followed conventional transfusion. Characteristics common to the fatalities (including an additional case reported before the study interval) were examined; all involved reinfusion of recovered blood under pressure. In the population studied, the incidence of fatal air embolism after the perioperative readministration of recovered blood was significantly higher than that after conventional transfusion. A model of such a system demonstrated that as much as 200 mL of air could enter the circulation in as little as 4 s, rendering visual detection and intervention extremely difficult. Education and guidelines to reduce the risk and mortality associated with this procedure are recommended.

Reinfusion of mediastinal blood in CABG patients: impact on homologous transfusions and rate of re-exploration

BACKGROUND

Reinfusion of mediastinal shed blood after cardiac surgery has been used in some centers to reduce exposure to homologous blood transfusions. The method has not been widely applied mostly because some studies have failed to demonstrate a significant benefit.

METHODS

A group of 675 consecutive patients undergoing first-time, isolated coronary artery bypass surgery (CABG) was studied. Prospective data was collected on the first 375 patients receiving autotransfusion (ATS) of mediastinal shed blood. The charts of 338 patients immediately preceding the institution of the ATS program at our institution (NO ATS group) were retrospectively reviewed. Transfusion of homologous blood products and rate of re-exploration for bleeding were closely monitored.

RESULTS

The two groups were identical. The net blood loss was significantly less in the ATS group than in the NO ATS group (1013 +/- 431 cc vs 1371 +/- 631 cc, p < 0.0001). Rate of exploration for postoperative bleeding was 1.5% in the ATS group and 5.0% in the NO ATS group (p < 0.01). In the ATS group, 51.9% of patients were not exposed to any homologous blood product (vs 17.8% in the NO ATS group, p < 0.0001). The ATS patients received on the average 2.9 +/- 7.2 units of blood products versus 6.4 +/- 9.7 units in the NO ATS group (p < 0.0001).

CONCLUSION

Reinfusion of mediastinal shed blood significantly reduces exposure to homologous blood transfusions and rate of reexploration. The ATS system reduces the number of re-explorations for coagulopathy-related postoperative hemorrhage.

Adverse effects of postoperative infusion of shed mediastinal blood

BACKGROUND

Postoperative infusion of shed mediastinal blood has been used in an effort to decrease blood usage after cardiac operations. Recent experience has suggested that this practice may actually lead to a delayed increase in bleeding.

METHODS

In a prospective, randomized study, 40 patients undergoing coronary artery bypass grafting with shed mediastinal blood collected in a cardiotomy reservoir were divided into two equal groups and studied during their first 4 hours in the intensive care unit. Shed mediastinal blood was directly infused in group I (n = 20), whereas in group II (n = 20), it was not. In group II, if a sufficient volume of red cells was present to allow processing (n = 5), washed red cells were infused. Variables studied before and after infusion were the amount of blood lost and infused, homologous blood transfused, complete blood count and differential, serum fibrinogen, fibrin split products, D-dimers, clotting factors, prothrombin time, activated partial thromboplastin time, thromboelastograms, plasma-free hemoglobin, complement factors C3 and C4, creatine kinase and its MB isoenzyme, and body temperature.

RESULTS

After infusion of shed mediastinal blood, elevated levels of fibrin split products and D-dimers were found in significantly more patients in group I. The thromboelastogram index was normal in 76% of patients in group II but in only 12.5% in group I. Group I also had an increase in band neutrophils, a greater number of febrile patients, higher serum levels of creatine kinase, its MB isoenzyme, and plasma-free hemoglobin, and greater blood loss during hours 3, 4, and 5 in the intensive care unit. The volume of red cells in shed mediastinal blood (hematocrit, 9% to 10%) was small, resulting in clinically insignificant autotransfusion when infused directly, and insufficient for cell processing in most patients.

CONCLUSIONS

These data support those in previous studies that direct infusion of shed mediastinal blood does not save substantial amounts of autologous red cells and can cause a delayed coagulopathy and other adverse effects that may be harmful to patients postoperatively.

Cell saver autologous transfusion: metabolic consequences of washing blood with normal saline

OBJECTIVE

To evaluate acid-base and electrolyte changes in high volume cell saver autologous blood transfusion when normal saline (0.9% NaCl) is used as the wash solution.

DESIGN

Open-label study.

MATERIALS AND METHODS

Nine anesthetized and anticoagulated mongrel dogs underwent 15 cycles of cell saver autologous blood transfusion. Eight percent of the circulating blood volume (125 mL) was withdrawn, washed with normal saline, and retransfused for each cycle.

MEASUREMENTS AND MAIN RESULTS

Analyses of acid-base, electrolyte, and hematologic parameters were performed on both systemic and the washed blood. The washed blood had increased levels of sodium and chloride. There were decreased levels in pH, Pco2, total CO2 (bicarbonate), lactic acid, potassium, total and ionized calcium, magnesium, inorganic phosphorus, total protein, and albumin. Systemically, in the animals, by the end of the study, there were significant increases in the levels of chloride, inorganic phosphorus, hemoglobin, and hematocrit and significant decreases in the levels of pH, total CO2, total and ionized calcium, magnesium, total protein, and albumin.

CONCLUSIONS

Acid-base, electrolyte, and hematologic changes occur when normal saline is used as the wash solution in high volume cell saver autologous blood transfusion. The washed blood with its elevation of sodium and chloride appears to reflect the constituents of the wash solution, normal saline. The depletion in the washed blood of PCO2, total CO2, potassium, total calcium, ionized calcium, magnesium, phosphorus, total protein, and albumin we feel is because of the absence of these electrolytes in the wash solution and their physical removal during salvaged blood separation and washing. The systemic acid-base and electrolyte changes primarily reflect the electrolyte pattern of the reinfused washed blood except for inorganic phosphorus. Inorganic phosphorus was maintained systemically, despite its wash out in the cell salvage process. This paradoxical finding may be caused by intracellular to extracellular inorganic phosphorus flux caused by the progressive systemic metabolic acidosis.

Intraoperative and postoperative blood salvage

Surgical patients present unique opportunities for reducing allogeneic transfusions via perioperative blood salvage. Intraoperative cell saver techniques enable the collection of autologous blood from the surgical field and cardiopulmonary bypass circuit for return to the patient. Washing and hemoconcentration creates a product with an average hematocrit of 50% that carries normal erythrocyte survival, with minimal coagulation factors of platelets. Postoperative autotransfusion of shed blood from chest tubes or surgical drains enables additional blood conservation, reducing allogeneic transfusions by as much as 50%. Both intermittent and continuous autotransfusion systems using standard chest drainage equipment are available that require minimal setup and maintenance at the bedside. The hematocrit of shed blood is 20-25%, with depletion of clotting factors and platelet function. Potential advantages of perioperative blood salvage include the ready availability of large volumes of patient-compatible blood, with optimal oxygen-carrying capacity, that is virtually free from the risk of viral contamination. Specific indications, contraindications, and techniques for the salvage and administration of these vital products are presented.

Conservation of blood during cardiovascular surgery

Conservative use of allogeneic red blood cell (RBC) transfusion is a growing trend in cardiovascular surgery. Recent advances in blood conservation measures have reduced, and in some cases eliminated, the need for allogeneic RBC transfusions in some of these patients. Reduced reliance on allogeneic RBC transfusion requires close collaboration among the clinical pathology, anesthesia, and surgery services managing the patient. Preoperative conservation measures include donation of autologous blood and treatment with recombinant human erythropoietin (Epoetin alfa). Meticulous surgical technique, moderate hemodilution, aprotinin, hemostatic techniques, blood salvage, and autotransfusion are intraoperative measures that can reduce blood loss. Postoperatively, even severe blood deficits can often be restored with adequate diet and rest and the use of actinics.

Release of inflammatory mediators in association with collection of wound drainage blood during orthopaedic surgery

Ten patients undergoing hip replacement surgery were studied regarding activation of complement and leukocytes in association with collection of wound drainage blood. The blood was collected postoperatively but not reinfused due to the possible risks with reinfusion of blood containing inflammatory mediators. Blood samples for analysis of complement activation (TCC), leukocyte activation (PMN elastase) and cytokines (Interleukin-6) were drawn preoperatively from the patients. Blood samples were also drawn intraoperatively from the wound. Samples were also drawn from the collected wound drainage blood, before and after blood was passed through a microporous filter. There were elevated concentrations of TCC, PMN elastase and IL-6 in the collected wound drainage blood before and after the filter. The filtration did not significantly reduce the concentrations of these factors. In the wound blood the concentrations were higher compared to those found in the systemic blood preoperatively, but lower compared to concentrations found in the collected drainage blood. The study demonstrates that the collection of wound drainage whole blood is associated with activation of complement, release of PMN elastase and cytokines.

Autotransfusion in the emergency patient

As the need for blood products increases in the veterinary emergency setting, the technique of autologous transfusion is being re-explored. Analogous transfusions provide an immediate source of blood with known compatibility to the patient. With the advent of passive canister collection systems, the technique is becoming simplified and affordable for the veterinary community. Although complications such as coagulopathies and microemboli have been reported with the procedure, attention to patient selection, technique, and patient monitoring following transfusion greatly minimizes potential drawbacks.

Release of cytokines, polymorphonuclear elastase and terminal C5b-9 complement complex by infusion of wound drainage blood

25 patients undergoing total hip replacement surgery were studied in an investigation of release of cytokines (interleukin-1 beta, IL-1 beta; interleukin-6, IL-6; interleukin-8, IL-8; and tumor necrosis factor-alpha, TNF-alpha), PMN elastase and terminal C5b-9 complement complexes (TCC) at the time of collection and transfusion of autologous blood. 15 patients received wound blood that was washed and centrifuged before being transfused as an erythrocyte suspension. In this blood there were no elevations in the concentrations of cytokines, TNF-alpha, PMN elastase or TCC, and there was no increase in these variables in plasma after transfusion of wound blood. 10 patients received postoperatively-collected drainage blood. There were high amounts of cytokines, PMN elastase and TCC in this blood, and filtration of the collected drainage blood did not reduce the concentrations of these factors, except those of TCC. When the collected drainage blood was infused, elevated plasma concentrations of IL-6, IL-8 and PMN elastase were observed 1 and 60 minutes after completing the transfusion. No differences regarding blood pressure, oxygen saturation (SpO2), and hemoglobin concentration between the groups were recorded.

The effect of multiple blood conservation techniques on donor blood exposure in adult coronary and valve surgery performed with a membrane oxygenator: a multivariate analysis on 1310 patients

The object of the study was to retrospectively evaluate protective and risk factors for receiving donor blood products and red cell transfusions after coronary and valve surgery performed with a hollow-fiber oxygenator and with multiple blood-saving techniques. During the period of January 1991 to June 1993, 1310 patients underwent primary coronary and valve surgery using a hollow-fiber oxygenator at our institution; the mean age of this population was 61 +/- 10 years; 977 patients were men (74.6%). Of these patients, 73.5% (963/1310) underwent coronary, 21.5% (281/1310) valve, and 5% (66/1310) combined surgery. Two hundred seventy-six (21.1%) needed donor blood product transfusions, while 153 (11.7%) patients underwent red cell transfusions. Significant risk factors for homologous blood product exposure after multivariate logistic regression analysis were, in order of importance: (1) postoperative blood loss (O.R. = 1.0009 per mL, p = 0.0000); (2) cardiopulmonary bypass (CPB) time (O.R. = 1.008 per min, p = 0.0001); (3) age at intervention (O.R. = 1.031 per calendar year, p = 0.0026); and (4) reoperation for bleeding (O.R. = 1.71, p = 0.0078). Protective factors were: (1) male gender (O.R. = 0.56, p = 0.0000); (2) preoperative withdrawal of autologous blood (O.R. = 0.66, p = 0.0018); and (3) a preoperative hematocrit greater than 34% (O.R. = 0.76, p = 0.0005).(ABSTRACT TRUNCATED AT 250 WORDS)

Reinfusion of postoperative wound drainage in total joint arthroplasty. Red blood cell survival and coagulopathy risk

Fifty patients with total joint arthroplasties (28 total hip arthroplasties, 11 total knee arthroplasties, and 11 bilateral total knee arthroplasties) received autotransfusions from their postoperative wound drainage. The blood was collected in a closed sterile drainage system without any additional anticoagulant. Pre- and postoperative measurements were made of the patient's hemoglobin, platelets, fibrinogen, haptoglobin, fibrin degradation products, and D-dimer (a specific type of fibrin degradation product). Red blood cell survival was assessed in 16 of the patients by labeling the shed blood with 51Cr sodium chromate prior to reinfusion. To control for fluid shifts, continued bleeding, and dilution effects of further transfusions in the immediate postoperative period, 10 patients also had their native blood labeled with 111In oxime. In this study, the mean estimated blood loss was 1,062 mL (+/- 1,247) with a mean wound drainage of 836 mL (+/- 338). Of this, a mean of 450 mL (+/- 261) of blood was was given back to the patient in addition to routine, preoperative autologous donated blood. Six (12%) patients experienced transient fevers at the time of retransfusion. Detailed hematologic studies were performed on the shed blood in 19 patients. The collected blood was completely defibrinated, but did contain fibrin degradation products, as indicated by the D-dimer level, and hemolyzed blood as the haptoglobin was reduced. Even though the blood containing the above breakdown products was reinfused to the patients, there were no clinical manifestations of disseminated intravascular coagulation. Both the hemolyzed and defibrinated products were subsequently cleared by the body.(ABSTRACT TRUNCATED AT 250 WORDS)