Reduction in Requirements for Allogeneic Blood Products: Nonpharmacologic Methods

Background. Various strategies have been proposed to decrease bleeding and allogeneic transfusion requirements during and after cardiac operations. This article attempts to document the usefulness, or lack thereof, of the nonpharmacologic methods available in clinical practice.

Methods. Blood conservation methods were reviewed in chronologic order, as they become available to patients during the perisurgical period. The literature in support of or against each strategy was reexamined critically.

Results. Avoidance of preoperative anemia and adherence to published guidelines for the practice of transfusion are of paramount importance. Intraoperatively, tolerance of low hemoglobin concentrations and use of autologous blood (predonated or harvested before bypass) will reduce allogeneic transfusions. The usefulness of plateletpheresis and retransfusion of shed mediastinal fluid remains controversial. Intraoperatively and postoperatively, maintenance of normothermia contributes to improved hemostasis.

Conclusions. Several approaches have been shown to be effective. An efficient combination of methods can reduce, and sometimes abolish, the need for allogeneic blood products after cardiac operations, inasmuch as all those involved in the care of cardiac surgical patients adhere thoughtfully to existing transfusion guidelines.     

Mediastinal Bleeding After Cardiopulmonary Bypass in Pediatric Patients

Background. The purpose of our review was to develop simple clinical recommendations to reduce the need for allogeneic blood transfusions in children undergoing cardiac operations.

Methods. The literature on hemostasis as it relates to children, cardiac disease in children, and pediatric heart surgery was reviewed. We also reexamined the efficacy of several strategies in this patient population: on-site monitoring of coagulation, transfusion of fresh whole blood, and administration of desmopressin, ε-aminocaproic acid, or aprotinin.

Results. Children with heart disease may present with preoperative thrombocytopenia, reduced platelet aggregation, and a decreased level of von Willebrand factor. Infants less than 6 months of age show a significant dilution of coagulation factors and decreased platelet counts during cardiopulmonary bypass. Fresh whole blood reduces blood loss in children younger than 2 years undergoing complex operations. Desmopressin does not reduce bleeding, whereas on-site monitoring, synthetic antifibrinolytics, and aprotinin require further evaluation in pediatric cardiac surgical patients.

Conclusions. The use of fresh whole blood to reduce blood loss in children younger than 2 years undergoing complex heart operations is recommended. Therapy for excessive bleeding after cardiopulmonary bypass will vary according to the patient's age, platelet count, and activated partial thromboplastin and prothrombin times.     

Blood coagulation and autologous blood transfusion in cardiac surgery

Study Objective: To review the basic pathophysiology of altered coagulation associated with cardiopulmonary bypass and autologous blood transfusion in cardiac surgery.

Design: Review of rational use of heparin, mechanisms and treatment of coagulation disorders, and autologous blood transfusion.

Setting: Cardiac surgery in community and academic hospitals.

Patients: Adult cardiac surgical patients.

Main Results: Heparin is most commonly used for anticoagulation during cardiopulmonary bypass. Although activated clotting time is widely used to assess heparin-induced anticoagulation, the minimum time to prevent clotting during cardiopulmonary bypass remains unclear. Activated clotting time is affected by many factors other than heparin, such as antithrombin III, blood temperature, platelet count, and age. The rational use of activated clotting time still must be defined.

The frequency of abnormal bleeding after cardiopulmonary bypass is significant. Although inadequate surgical hemostasis is the most frequent cause of bleeding, altered coagulation often is present. A decreased number of functional platelets is one of the important causes of bleeding diathesis. Platelet dysfunction is induced by perioperative medication such as aspirin. Cardiopulmonary bypass decreases functional platelets by degranulation, fragmentation, and loss of fibrinogen receptors. Medications such as prostacyclin and iloprost may be useful to protect these platelets. Desmopressin increases factor VIII:C and von Willebrand's factor, leading to a decrease in bleeding time. Desmopressin may be useful to decrease blood loss in repeat cardiac operations, complex cardiac surgery, and abnormal postoperative bleeding.

Patients undergoing coronary artery bypass grafting immediately after streptokinase infusion also are at risk for abnormal bleeding. Transfusion of fresh frozen plasma and cryoprecipitate may be necessary.

Autologous blood transfusion is cost-effective and the safest way to avoid or decrease homologous blood transfusion. Predonation, intraoperative salvage, and postoperative salvage are encouraged. Erthroprotein may be useful in increasing the amount of predonation red cells.

Conclusions: Coagulation disorders in cardiac surgery are caused by many factors, such as heparin, platelet dysfunction, and fibronolysis. Rational use of blood component therapy and medications such as heparin, protamine, and desmorpessin are mandatory. Autologous blood transfusions is very useful in decreasing or obviating the use of homologous blood transfusion.     

Treatment of Excessive Mediastinal Bleeding After Cardiopulmonary Bypass

Background. Excessive mediastinal bleeding after cardiopulmonary bypass is one of the most frequently reported complications of cardiac operations. Appropriate treatment requires a rapid and effective diagnostic work-up, based on the knowledge of the pathophysiology induced by cardiopulmonary bypass.

Methods. Possible causes, diagnostic methods available, and therapeutic approaches are reviewed in the light of the literature published on excessive bleeding after cardiac operations.

Results. When bleeding is massive (>250 to 300 mL/h for the first 2 hours, >150 mL/h thereafter), immediate surgical reexploration is mandatory. When bleeding is less important (50 to 150 mL/h), the decision to reoperate should be based on the presence of hemodynamic compromise or a suspected surgical cause. Otherwise, coagulation testing should allow the correction of hemostatic defects as appropriate with protamine, platelet concentrates, fresh frozen plasma, desmopressin, or antifibrinolytics. Hypothermia and hypotension should be corrected and a trial of positive end-expiratory pressure may be considered if diffuse mediastinal oozing (especially from the bed of the mammary artery) is suspected.

Conclusions. A protocol is suggested to guide treatment, taking into account the rapidity of blood loss and the suspected underlying cause.     

Desmopressin does not reduce bleeding and transfusion requirements in congenital heart operations

Background. Desmopressin (DDAVP) has been evaluated in many randomized clinical trials as a means to reduce blood loss and transfusion of allogeneic blood in cardiac operation requiring cardiopulmonary bypass. Desmopressin reduces blood loss in adult patients with excessive bleeding after cardiac operation. Its usefulness in patients undergoing complex congenital heart repair with cardiopulmonary bypass is unproved.

Methods. Sixty patients younger than 40 years of age scheduled for complex congenital heart operation (44 redo, 16 primary) were enrolled in this prospective, randomized, double-blind trial. Desmopressin 0.3 μg/kg or placebo was administered 10 minutes after protamine administration. Transfusion requirements and postoperative blood loss were recorded. Differences were analyzed using analysis of variance with a p value of 0.05 or less used to denote statistical significance.

Results. There were no differences in demographic or surgical characteristics between the DDAVP or placebo groups. There was no difference in blood loss and transfusion requirements between the DDAVP and placebo groups. During the intraoperative postinfusion time period, the median blood loss for redo patients was 343 versus 357 mL/m² for placebo versus DDAVP, respectively, and for primary patients, the median blood loss was 277 versus 228 mL/m².

Conclusions. The prophylactic use of DDAVP to reduce excessive bleeding or transfusion requirements in patients undergoing complex congenital heart operations is not warranted.     

Reduction in Requirements for Allogeneic Blood Products: Pharmacologic Methods

Background. Numerous articles describe the reduction of perioperative bleeding by the therapeutic or prophylactic administration of drugs such as prostacyclin, desmopressin, and natural or synthetic antifibrinolytics.

Methods. A review of the literature was carried out to help the reader define the indications of these drugs during cardiopulmonary bypass operations, highlight the questions that remain concerning their indications and modes of action, and suggest future studies to answer these remaining questions.

Results. Prostacyclin reduces platelet trauma induced by extracorporeal circulation but does not effectively reduce postoperative bleeding and transfusion requirements. Desmospressin acts as a “glue,” improving platelet adhesion, and may be effective when postoperative bleeding is excessive, but its routine use in cardiac operations cannot be recommended. Natural and synthetic antifibrinolytics inhibit plasmin and plasmin-induced platelet dysfunction. These agents have been shown to decrease bleeding and the need for allogeneic transfusions after open heart operations. However, with antifibrinolytic drugs, the risk of thromboembolic phenomena cannot be neglected. With aprotinin, this risk appears to be minimal when the drug is used at concentrations high enough to inhibit plasma kallikrein also.

Conclusions. Prophylactic antifibrinolytics are efficacious, but their routine use remains controversial, both for economic reasons and for fear of thromboembolic complications.     

Late complications of tissue glues in aortic surgery

Background. Tissue glues are used in cardiothoracic surgery as an adjunct to operative procedures where tissues are frail, as in aortic dissection, or where added hemostasis is required. This study was undertaken to review the use of tissue glue in our institution over a 5.5-year period. The aim of the study was to identify any potentially glue-related complications.

Methods. A review of tissue glue use for the period from January 1993 to September 1998 was performed and pre-, intra-, and postoperative parameters were collected. After some unusual surgical findings, of special interest was a range of pathology found at late reoperation.

Results. A total of 67 cases of tissue glue use were identified, with the majority of operations for type A dissection (76%). There were two intraoperative deaths. Twenty-seven of 65 patients (41%) required 29 further open chest operations; of these, 17 were for acute problems of bleeding or tamponade. Twelve patients (18%) underwent late reoperations months to years later. Nine of these patients, concentrated in two operative groups (7 patients with aortic valve resuspension and 2 patients who had undergone “switch” operations for transposition of great vessels), displayed complications related to the application of gelatin-resorcinol-formaldehyde (GRF) tissue glue.

Conclusions. Indications for tissue glues in cardiothoracic surgery must be carefully considered. We have reviewed our use of some tissue glues in acute type A aortic dissections and in pediatric cardiac patients and have discontinued the use of GRF glues because of unsatisfactory long-term complications.     

Granulocyte Phagocytic Function Is Impaired During Cardiopulmonary Bypass

Background. The presence of impaired phagocytic function of the reticuloendothelial system after cardiac operations using cardiopulmonary bypass remains controversial.

Methods. In this study, the phagocytic function of granulocytes in 14 patients undergoing cardiac operations with cardiopulmonary bypass was examined using a chemiluminescence method. Seven patients with abdominal aortic aneurysms served as controls. Electron microscopy also was employed to evaluate morphologic changes.

Results. The 14 cardiac patients showed impaired phagocytic function from immediately after operation until 12 hours after the operation. This phagocytic function recovered within 24 hours. The 7 control patients showed no change in phagocytic function during or after the operation. Scanning electron microscopic examination of the cardiac patients' granulocytes revealed the loss of villi on cell surfaces immediately after operation. However, these villi were restored within 24 hours after the operation.

Conclusions. The phagocytic function of granulocytes was impaired in the early postoperative period in patients undergoing cardiopulmonary bypass, and this was probably due to the loss of villi on granulocyte surfaces.     

Surgical hemostatic agents: assessment of drugs and medical devices

Surgical hemostatic agents are indicated to improve hemostasis when conventional techniques (compression, sutures or electrocoagulation) are inadequate. The National French Authority for Health (Haute Autorité de santé [HAS]) set out to assess these products (medical devices and agents) to determine their optimal utility. This evaluation included one class of products containing some form of human fibrinogen and thrombin and eight classes of medical devices and automated devices to prepare autologous fibrin. The assessment was based on a systematic review of the literature and expert opinion of health care professionals. The main measures of effectiveness of hemostatic agents were the success rate as expressed in terms of the time necessary to obtain adequate hemostasis, the volume of intra and/or postoperative blood loss, the need for blood transfusions, complication rate, duration of operations and hospital stay. A meta-analysis and 52 controlled randomized studies were selected involving cardiac or vascular surgery (19), ENT surgery (11), gastrointestinal surgery (5), urology (4), orthopedic surgery (4). Approximately half of the studies retained in this analysis evaluated blood derived agents (fibrin sealants) while the other half evaluated medical devices. The working group considered that there is not any evidence that these surgical hemostatic agents decrease the rates of transfusion, complications, reoperation, mortality, duration of operation and/or hospital stay. The working group considered that the use of surgical hemostatic agents to improve the safety of hemostasis in the absence of identified bleeding as an alternative to adequate conventional hemostasis was not justified. Surgical hemostatic agents can be used in ad hoc settings, as a complement to conventional methods to control persistent bleeding after conventional hemostatic techniques, or when abundant bleeding has led to biologic hemostatic disorders. The working group also distinguished several particular settings (mouth and dental care in patients under antiagregant or anticoagulation therapy, central nervous system surgery or acute aortic dissection). Comparative data are insufficient to determine if one product is superior to another for a specific use. To evaluate the clinical value of these products, methodologically sound clinical studies are necessary.     

Laboratory Evaluation of Hemostasis Before Cardiac Operations

Background. Several opinions prevail on the necessity and on the choice of laboratory coagulation tests to perform before cardiac operations. This review aims at providing simple and clinically relevant recommendations.

Methods. The literature on preoperative coagulation testing was reexamined, taking into account the low prevalence of unknown and unsuspected hemorrhagic disease, and the risk of false positive results.

Results. Carefully controlled, randomized trials are lacking but it seems appropriate to perform a few inexpensive tests (platelet count, activated partial thromboplastin time, and prothrombin time), mainly to obtain baseline values for patients who are about to undergo a major hemostatic challenge. A more complete coagulation profile (eg, bleeding time, fibrinogen concentration, thrombin time) should be considered in patients who present with a history of bleeding.

Conclusions. A careful medical history is the key element to detect a bleeding disorder. Only a very limited coagulation profile should be obtained in asymptomatic patients before cardiac operations.     

Adjustable tourniquet to manipulate pulmonary blood flow after Norwood operations

Background. Survival after first-stage palliative Norwood operations for single ventricle with systemic outflow obstruction is mainly dependent on a balanced ratio of pulmonary blood flow to systemic blood flow. Here we report the clinical results using a modified technique that allows a controlled systemic-to-pulmonary shunt flow to prevent pulmonary overcirculation.

Methods. From 1995 to 1998, of 26 infants undergoing first-stage palliative Norwood operations, 7 had placement of an adjustable tourniquet around a modified right Blalock-Taussig shunt.

Results. Hospital survival was 20 of 26 patients (77%). All 7 patients in whom snaring of the shunt was indicated survived. Two patients underwent repeated adjustment, in 5 patients the tourniquet could be removed during delayed sternal closure, and 2 patients were discharged with the shunt partially snared.

Conclusions. The snare-controlled systemic-to-pulmonary shunt allows improved hemodynamic stability after reconstructive surgery for hypoplastic left heart syndrome or other similar complex cardiac defects by reducing the risk of pulmonary overcirculation. It is simple and rapidly executed. The option of graded banding of the shunt depending on the hemodynamic situation increases flexibility and safety after cardiopulmonary bypass or at any time in the postoperative period.     

Endoscopic diagnostics and management of postoperative gastrointestinal bleedings

The features of clinical course, the frequency and the pattern of gastrointestinal bleedings after diverse abdominal operations were studied over a period of time from 1993 to 2006. Postoperative gastrointestinal bleedings were observed at 503 patients. The frequency of postoperative gastrointestinal bleedings amounted 0.5% after operations on account of purulent diseases with different localization, 0.6% after abdominal and cardiovascular operations, 0.8% after lung operations, 1.5% after operations on the account of burn disease, 6.1% after hepatopancreatobiliary operations. In accordance with the stages of postoperative period, distinctions in endoscopic picture and the tactics of treatment early and late bleedings were distinguished during the investigation. It has been established, that blood supply disturbance in portal vein, manifested by transient portal hypertension is, one of the most important pathogenetic factors of development of bleeding after hepatopancreatobiliary operations along with acute erosive (ulcerous) affection, caused by stress or trauma, and multiple organ failure. The features of clinical course of postoperative bleedings were studied in different groups of surgical patients. The comparative evaluation of efficacy of endoscopic methods of hemostasis (injection,various endoclips, hydrothermocoagulation, argon-plasma coagulation) was carried out. It was shown that the application of new methods of endoscopic sanation and investigation of the upper gastrointestinal tract had resulted in increase of frequency of exposure of gastrointestinal bleeding source from 69.8% to 88.4% at primary urgent esophagogastroscopy. The efficacy of hemostasis at postoperative gastrointestinal bleeding raised from 70.3% to 92.4%.     

Management of catheter-induced pulmonary artery perforation: a rare complication in cardiovascular operations

Background. Pulmonary artery perforation is a rare but often fatal complication of the pulmonary artery catheter occurring in cardiovascular operations and at catheterization facilities. We used our experience and a review of the literature to formulate diagnostic and management strategies.

Methods. During a 13-year period, 12 patients with pulmonary artery perforations were treated in a center that performed an average of 860 open-heart procedures per year. Clinical presentation varied from minor hemoptysis to major airway hemorrhage, hypoxia, exsanguination, and cardiac arrest. Airway bleeding occurred shortly after weaning from cardiopulmonary bypass in 5 patients or postoperatively after wedging the catheter in 6. One patient developed a hemothorax and had a cardiac arrest. Treatment included assurance of gas exchange, endobronchial lavage, isolation of the bleeding bronchus and control of hemorrhage by conservative therapy, pulmonary resection, pulmonary artery repair, and arterial embolization.

Results. Five of the 12 patients died (42%). Recurrent hemorrhage occurred in 40% of patients (2 of 5) treated conservatively compared with none of the patients (0 of 7) having surgical treatment. Forty three percent of patients (3 of 7) treated surgically died; 20% of patients (1 of 5) treated conservatively died. One patient succumbed without treatment.

Conclusions. Pulmonary artery perforation is a rare and often fatal complication of pulmonary artery catheterization. This was apparent with patients who had airway hemorrhages as a result of weaning from cardiopulmonary bypass or after balloon inflation. Recurrent and fatal hemorrhage was frequent in patients treated by conservative therapy alone. Surgical intervention was effective in control of hemorrhage but did not reduce the number of deaths. Treatment remains highly individualized. It is advisable to be cautious in inserting Swan-Ganz catheters and to avoid their use unless absolutely necessary.     

Benefits of surgical repair of coarctation of the aorta in patients older than 50 years

Background. Most patients with unrepaired coarctation of the aorta die before the age of 50 years. In patients who present at an older age, the indications for surgical treatment are controversial because the benefits of operating are unclear.

Methods. At follow-up investigation from 0.5 to 11.5 years (mean, 4 years) after primary surgical correction of coarctation in 15 patients aged 50 to 63 years (mean, 54 years), we analyzed the preoperative and postoperative complications, symptoms, need for antihypertensive drugs, and blood pressure at rest and during exercise.

Results. Preoperatively no patient had normal blood pressure at rest despite combined antihypertensive medication. There was no significant mortality or morbidity after repair. At follow-up examination only 3 patients had at rest mild hypertension, the other 12 patients were normotensive. Of the 11 tested patients, 8 displayed systolic arterial hypertension during exercise.

Conclusions. Surgical correction of coarctation can be performed after the age of 50 years with low surgical risk. Operation reduces systolic hypertension at rest and permits more effective medical treatment. Despite persistence of the hypertension during exercise, symptomatic improvement occurs in most patients.     

Impact of protamine sulfate on hemostasis system after operations with artificial circulation

Effects of different doses and lots of protamine sulfate on hemostasis system after cardiac operations with artificial circulation are analyzed. Overall 982 patients underwent cardiac operations with artificial circulation. Quality and purity of protamine may be the causes of side effects. Negative effect of high doses of protamine on hemostasis system is demonstrated. Thrombocyte dysfunction is the main cause of intensive postoperative bleeding after administration of protamine high doses.     

Valvular heart operation in patients with previous mediastinal radiation therapy

Background. The outcome of valvular heart operations in patients with previous mediastinal radiation therapy was studied.

Methods. This is a single center retrospective study of 60 patients (37 females, 23 males) with a mean age of 62 ± 15 years (28 to 88 years old) operated on from January 1976 to December 1998. Valvular heart operations performed included aortic valve replacements (n = 26), mitral valve procedures (n = 16), tricuspid valve procedures (n = 6), and multiple valve procedures (n = 12). A total of 264 clinical, hemodynamic, electrocardiographic and echocardiographic variables were analyzed.

Results. Total follow-up was 199 patient-years with a mean of 3.3 ± 3.1 years and a range of 0 to 12.4 years old. Early mortality was 7 patients (12%). Early mortality in patients with constrictive pericarditis was 40% (4 of 10) compared with 6% (3 of 50) in patients without constrictive pericarditis. By univariate analysis, early mortality was associated with constrictive pericarditis (p = 0.011), reduced preoperative ejection fraction (p = 0.015), and longer cardiopulmonary bypass times (p = 0.037). A total of 14 patients (23%) required permanent pacemaker placement before (n = 7), during (n = 1), or early (n = 6) after valvular heart operations. There were 19 late deaths (malignancies, 7; heart failures, 5; other cardiac, 4; and other noncardiac, 3). Overall survival and freedom from late cardiac death and cardiac reoperation at 5 years for hospital survivors were 66% ± 8%, 82% ± 7%, and 93% ± 4%, respectively. By univariate analysis, late cardiac death was associated with low ejection fraction (p = 0.002), New York Heart Association (NYHA) functional class IV (p = 0.004), preoperative congestive heart failure (p = 0.02), and preoperative atrial fibrillation (p = 0.038). Eighty-five percent of the discharged patients were in NYHA functional class I or II at follow-up.

Conclusions. Early results of valve replacement after mediastinal radiation therapy were good except in the presence of constrictive pericarditis. Long-term outcome was limited by malignancy and heart failure. Early surgical intervention is recommended before the development of risk factors for late death, namely, severe symptoms, left ventricular dysfunction, and atrial fibrillation.     

Management of bleeding and coagulopathy after heart surgery

Mechanisms of bleeding common to virtually all patients after heart surgery are platelet dysfunction, enhanced fibrinolysis, dilution of all components of the coagulation system, and the presence of heparin and protamine. The use of warfarin is increasing in patients with heart disease requiring surgery. The replenishment of vitamin K-dependent factors beyond a normal prothrombin time is not assessable, and the dilution associated with cardiopulmonary bypass can reach coagulopathic levels. Optimal preoperative preparation is required and intraoperative therapy initiated when indicated. Individualized heparin and protamine dosing, antifibrinolytic drug administration, minimization of blood loss and dilution, and minimal time on cardiopulmonary bypass are basic adjuncts to meticulous surgical hemostasis. When bleeding is observed in the postoperative period, a sequential assessment of the probable cause leads to initial therapy while laboratory test results are obtained. Ongoing assessment for hemodynamic instability caused by accumulated mediastinal blood is needed while managing the bleeding patient. A chest radiograph and transesophageal echocardiogram can be useful in diagnosing cardiac tamponade.     

Hyperbaric oxygenation in the treatment of bleeding gastroduodenal ulcers]

It is shown on the basis of analysis of the results of treatment of 179 patients that the use of hyperbaric oxygenation in the complex surgical management of ulcerative gastroduodenal bleeding reduced the number of postoperative complications by a factor of 3.3 and led to a decrease of mortality from 20 to 1%. The authors confirm the expedience of including hyperbaric oxygenation in the complex of therapeutic measures in patients with bleeding ulcers under conditions of accomplished hemostasis by conservative or surgical methods in one of three suggested variants: in preparation of the patients for operation in the postponed period; after operative interventions carried out at the peak of bleeding; before and after operations on patients with moderate and severe blood loss and concomitant diseases. The sessions should be conducted under pressure of 2 atm for 60 minutes.     

Allogenic blood transfusion for surgery

Blood transfusion against surgical patients is mainly as a replacement therapy for intra-operative bleeding. Transfusion trigger depends on to maintain 12 ml/kg/min oxygen carrying capacity. Oxygen consumption depends on oxygen carrying capacity which multiplicity hemoglobin concentration and cardiac output. The government of United States decided the transfusion trigger of surgical patients at hemoglobin 7.0 g/dl except patients who have cardiac problem at 1988. The indication of plasma and platelet transfusion is limited in surgical field. Because bleeding tendency is usually a contra-indication of surgery itself. Dilution coagulopathy due to massive bleeding exceed one blood volume is the main indication of plasma and platelet transfusion. It is necessary to administrate fresh frozen plasma for replenishing coagulation function with 30% of one body plasma volume when prothrombin time prolong more than 16 seconds. Platelet transfusion is effective for hemostasis in case of massive bleeding which exceed 1.5 blood volume and also peripheral blood platelet count indicate lower than 50,000/mm3.     

Brain SPECT imaging and neuropsychological testing in coronary artery bypass patients

Background. Cognitive deficits appear frequently after cardiac operation. While the etiology remains unclear, alterations in cerebral perfusion during cardiopulmonary bypass may be causative. Single photon emission computed tomography (SPECT) scanning utilizes a radiopharmaceutical to provide images of cerebral perfusion. We proposed to study the cerebral circulation of patients during coronary artery bypass operation employing cardiopulmonary bypass.

Methods. Thirty-five neurologically normal patients underwent preoperative SPECT brain scanning and neuropsychological testing. A second SPECT brain perfusion scan was obtained by administering the radioisotope during cardiopulmonary bypass, with subsequent scanning upon completion of the procedure. Postoperative neuropsychological testing was performed prior to discharge.

Results. Fourteen (40%) of patients demonstrated significant neuropsychological decline. Patients who suffered cognitive impairment were no different in demographic, general health, or surgical variables. Patients who demonstrated neuropsychological decline had significantly poorer cerebral perfusion both at baseline and during operation.

Conclusions. Impaired cerebral perfusion at baseline may identify patients at risk for cognitive injury after cardiac operation. Alterations in cerebral perfusion during cardiopulmonary bypass is common, and may be a factor in neuropsychological deficits seen after cardiac operation.