Denise Wozny

The Cardiotomy Trial: A Randomized, Double-Blind Study to Assess the Effect of Processing of Shed Blood During Cardiopulmonary Bypass on Transfusion and Neurocognitive Function

Background— Reinfusion of unprocessed cardiotomy blood during cardiac surgery can introduce particulate material into the cardiopulmonary bypass circuit, which may contribute to postoperative cognitive dysfunction. On the other hand, processing of this blood by centrifugation and filtration removes coagulation factors and may potentially contribute to coagulopathy. We sought to evaluate the effects of cardiotomy blood processing on blood product use and neurocognitive functioning after cardiac surgery. Methods and Results— Patients undergoing coronary and/or aortic valve surgery using cardiopulmonary bypass were randomized to receive unprocessed blood (control, n=134) or cardiotomy blood that had been processed by centrifugal washing and lipid filtration (treatment, n=132). Patients and treating physicians were blinded to treatment assignment. A strict transfusion protocol was followed. Blood transfusion data were analyzed using Poisson regression models. The treatment group received more intraoperative red blood cell transfusions (0.23±0.69 U versus 0.08±0.34 U, P=0.004). Both red blood cell and nonred blood cell blood product use was greater in the treatment group and postoperative bleeding was greater in the treatment group. Patients were monitored intraoperatively by transcranial Doppler and they underwent neuropsychometric testing before surgery and at 5 days and 3 months after surgery. There was no difference in the incidence of postoperative cognitive dysfunction in the 2 groups (relative risk: 1.16, 95% CI: 0.86 to 1.57 at 5 days postoperatively; relative risk: 1.05, 95% CI: 0.58 to 1.90 at 3 months). There was no difference in the quality of life nor was there a difference in the number of emboli detected in the 2 groups. Conclusions— Contrary to expectations, processing of cardiotomy blood before reinfusion results in greater blood product use with greater postoperative bleeding in patients undergoing cardiac surgery. There is no clinical evidence of any neurologic benefit with this approach in terms of postoperative cognitive function.

Effects of Mild Hypothermia and Rewarming on Renal Function After Coronary Artery Bypass Grafting

BACKGROUND Hypothermia is a potential strategy for visceral organ protection during cardiopulmonary bypass (CPB). We report data from two randomized studies evaluating mild hypothermia and rewarming on postoperative renal function in cardiac surgical patients. METHODS Patients undergoing nonemergency, isolated coronary artery bypass grafting were enrolled into two studies. In the first, 223 patients were cooled to 32 degrees C during CPB and randomly assigned to rewarming to 37 degrees C (RW-37 degrees) or 34 degrees C (RW-34 degrees). The second study randomized 267 patients to sustained mild hypothermia at 34 degrees C (S-34 degrees) or normothermia (S-37 degrees) without rewarming. Serum creatinine levels were measured. Creatinine clearance was calculated. Significant renal dysfunction was defined as a 25% increase in serum creatinine or a 25% decrease in creatinine clearance postoperatively. RESULTS Postoperative serum creatinine levels were persistently higher in the RW-37 degrees patients than in the RW-34 degrees group (p < 0.01). RW-37 degrees patients had a higher incidence of renal dysfunction (17%) than RW-34 degrees patients (9%, p = 0.07). Sustained mild hypothermia had no beneficial effect on postoperative serum creatinine levels (p = 0.44) or significant renal dysfunction: S-34 degrees, 20% vs S-37 degrees, 15% (p = 0.28). Diabetes (odds ratio [OR], 1.6; 95% confidence interval [CI] 1.3 to 2.1), prolonged CPB time (OR, 1.1; 95% CI, 1.0 to 1.2), and rewarming (OR, 1.4; 95% CI, 1.0 to 1.9) were independent risk factors for significant renal dysfunction. Renal dysfunction was associated with longer hospital stay (8.4 +/- 0.8 vs 6.8 +/- 04 days, p < 0.001). CONCLUSIONS Sustained mild hypothermia does not improve renal outcome. However, rewarming on CPB is associated with increased renal injury and should be avoided.

Predictors of Early Neurocognitive Deficits in Low-Risk Patients Undergoing On-Pump Coronary Artery Bypass Surgery

Background— Postoperative cognitive deficits (POCDs) are a source of morbidity and occur frequently even in low-risk patients undergoing cardiac surgery. Predictors of neurocognitive deficits can identify potentially modifiable risk factors as well as high-risk patients in whom alternate revascularization strategies may be considered. Methods and Results— 448 patients undergoing coronary surgery (coronary artery bypass graft [CABG]) underwent standardized preoperative and postoperative neurocognitive testing as part of 2 randomized trials evaluating the effects of mild hypothermia during coronary surgery. Prospectively collected data were used to identify univariate predictors of POCDs and multivariable logistic regression models were constructed. Models were bootstrapped 1000 times. POCDs occurred in 59% of patients. Significant univariate predictors included intraoperative normothermia, impaired left ventricular (LV) function, higher educational level, elevated serum creatinine and reduced creatinine clearance, prolonged intubation time, intensive care unit (ICU) stay, and hospital stay. Advanced age, presence of carotid disease, and cardiopulmonary bypass time were not associated with increased POCDs in this cohort. Multivariable modeling identified intraoperative normothermia (odds ratio [95% confidence interval] −1.15 [1.01, 1.31]), poor LV function (1.53 [1.02, 2.30]), and elevated preoperative creatinine (1.01 [1.00 to 1.03] for every 1 mmol/L increase), prolonged (>24 hours) ICU stay (1.88 [1.27 to 2.79]), and higher educational level (1.52 [1.01 to 2.28]) as independent predictors of POCD occurrence. Conclusions— Mild hypothermia, in the intraoperative and perioperative period, may be a protective strategy for the prevention of POCDs. Patients with elevated pre-operative creatinine and poor LV function carry a higher risk of POCDs and may benefit from revascularization strategies other than conventional on-pump CABG.

Cerebral Emboli Detected by Transcranial Doppler During Cardiopulmonary Bypass Are Not Correlated With Postoperative Cognitive Deficits

Background and Purpose— High-intensity transient signals (HITS) are the transcranial Doppler representation of both air and solid cerebral emboli. We studied the frequency of HITS associated with different surgical maneuvers during cardiopulmonary bypass for coronary artery bypass graft surgery and their association with postoperative cognitive dysfunction (POCD). Methods— We combined 356 patients undergoing coronary artery bypass graft from 2 clinical trials who had both neuropsychological testing (before, 1 week and 3 months after surgery) and transcranial Doppler during cardiopulmonary bypass. HITS were grouped into periods that included: cannulation, cardiopulmonary bypass onset, aortic crossclamp-on, aortic crossclamp-off, side clamp-on, side clamp-off, and decannulation. POCD was defined by a decreased combined Z-score of at least 2.0 or reduction in Z-scores of at least 2.0 in 20% of the individual tests. Results— Incidence of POCD was 47.3% and 6.3% at 1 week and 3 months after surgery. There was no association between cardiopulmonary bypass counts of HITS and POCD at 1 week (P=0.617) and 3 months (P=0.110). No differences in HITS counts were identified at any of the surgical periods between patients with and without POCD. Factors affecting HITS counts were surgical period (P<0.0001), blood flow velocity (P=0.012), cardiopulmonary bypass duration (P=0.040), and clinical study (P=0.048). Conclusions— Although cerebral microemboli have been implicated in the pathogenesis of POCD, in this study that included low-risk patients undergoing coronary artery bypass surgery, there was no demonstrable correlation between the counts of HITS and POCD.

Are we doing everything we can to conserve blood during bypass? A national survey.

Introduction: Despite major advances in biomaterial research and blood conservation, bleeding is still a common complication after cardiopulmonary bypass and cardiac surgery remains a major consumer of blood products. Although the underlying mechanisms for these effects are not fully established, two proposed major etiologies are the hemodilution associated with the use of the heart-lung machine and the impact of reinfusion of shed cardiotomy blood. Therapeutic strategies that primarily encompass the use of devices or technologies to overcome these effects may result in improved clinical outcomes. Objective: To determine the extent to which 1) lipid/leukocyte filtration and centrifugal processing of cardiotomy blood, and 2) modified ultrafiltration (MUF) are currently applied in adult cardiac surgery in Canada. Methods: A questionnaire was mailed to the chief perfusionist at all adult cardiac surgical centers in Canada, addressing details regarding the frequency of use of cardiotomy blood processing and MUF. Results: All questionnaires (36, 100%) were completed and returned. With regards to cardiotomy blood management, in 21 centers (58%), no specific processing steps were utilized exclusive of the integrated cardiotomy reservoir filter. Of the remaining centers, two (6%) reported using lipid/leukocyte filtration and 15 (42%) reported washing their cardiotomy blood. Three centers (8%) reported using MUF at the end of CPB. Conclusions: Despite growing concern about the potential detrimental effects of cardiotomy blood, few centers in Canada routinely manage this blood with additional filtration and/or centrifugal processing prior to reinfusion. Similarly, MUF, demonstrated to be effective in the pediatric population, has not seen popular application in adult cardiac surgical practice.

Research awards program of the Canadian Anesthesiologists' Society/Canadian Anesthesia Research Foundation: survey of past recipients.

PurposeTo review the effectiveness of the Research Grants, Career Scientist Award and Fellowship Program (RGCSFP) of the Canadian Anesthesiologists’ Society (CAS)/Canadian Anesthesia Research Foundation (CARF) by surveying past recipients.MethodsThe CAS Research Committee database of past RGCSFP recipients was reviewed to identify all past award recipients from the time of program inception in 1985 until the year 2005. A questionnaire was mailed to all past recipients with retrievable addresses. The questionnaire asked specific questions regarding past and current research, publications, grant procurement and mentoring of trainees. In addition, opinions regarding the program’s effectiveness were solicited.ResultsOf the 100 mailed survey forms, 66 (66%) were completed and returned. The number of original published articles per respondent was 30.1 ±28.5 (mean ± SD) at the time of the survey, and the life-time number of all publication types was 38.5 ± 34.6. Cumulative research funding increased in relation to the number of years in research, and amongst past recipients with > 15 years in research, individual research funding from all sources was

Neuroprotective effect of mild hypothermia in patients undergoing coronary artery surgery with cardiopulmonary bypass a randomized trial

585,747 ±

Effects of Methylprednisolone and a Biocompatible Copolymer Circuit on Blood Activation During Cardiopulmonary Bypass

773,716. Ninety-six percent of respondents agreed or strongly agreed that the program was valuable.ConclusionsThe RGCSFP has supported a large number of new and established anesthesia investigators in Canada, and these individuals have demonstrated high research productivity. The program is considered to be very valuable according to past recipients.RésuméObjectifEvaluer l’efficacité du programme de bourses de recherche, de bourses de carrière en recherche et de fellowship (RGCSFP) de la Société canadienne des anesthésiologistes (SCA) et de la Fondation canadienne de recherche en anesthésie (FCRA) par une enquête auprès des anciens récipiendaires.MéthodeLa base de données du Comité de recherche de la SCA au sujet des anciens récipiendaires de bourses RGCSFP a été examinée afin d’identifier tous les récipiendaires depuis la mise en place du programme en 1985 jusqu’en 2005. Un questionnaire a été envoyé à tous les anciens récipiendaires dont on a retrouvé l’adresse. Le questionnaire posait des questions spécifiques sur leurs recherches passées et présentes, leurs publications, l’obtention de bourse et le mentorat de stagiaires. En outre, nous avons également demandé leurs opinions sur l’efficacité du programme.RésultatsDes 100 questionnaires postés, 66 (66 %) ont été complétés et renvoyés. Le nombre d’articles originaux publiés par répondant était de 30,1 ± 28,5 (moyenne ± SD) lors de l’enquête, et le nombre de publications de tous types à vie était de 38,5 ± 34,6. Le financement de recherche cumulatif a augmenté en fonction du nombre d’années de recherche, et parmi les récipiendaires passés ayant effectué > de 15 ans de recherche, le financement de recherche individuel, toutes sources confondues, était de

Effects of sustained mild hypothermia on neurocognitive function after coronary artery bypass surgery: a randomized, double-blind study.

585 747 ±

Neuroprotective effect of mild hypothermia in patients undergoing coronary artery surgery with cardiopulmonary bypass: Five-year follow-up of a randomized trial

773 716. Parmi les répondants, 96 % étaient d’accord ou tout à fait d’accord que le programme était utile.ConclusionLe RGCSFP a soutenu un grand nombre de chercheurs en anesthésie au Canada, qu’ils soient nouveaux ou établis, et ces personnes ont démontré une grande productivité en recherche. Le programme est considéré comme très utile par les anciens récipiendaires.