Continuous-Flow Cell Saver Reduces Cognitive Decline in Elderly Patients After Coronary Bypass Surgery

Abstract

Background-Cerebral microembolization during cardiopulmonary bypass may lead to cognitive decline after cardiac surgery. Transfusion of the unprocessed shed blood (major source of lipid microparticulates) into the patient during cardiopulmonary bypass is common practice to reduce blood loss and blood transfusion. Processing of shed blood with cell saver before transfusion may limit cerebral microembolization and reduce cognitive decline after surgery. Methods and Results-A total of 226 elderly patients were randomly allocated to either cell saver or control groups.Anesthesia and surgical management were standardized. Epiaortic scanning of the proximal thoracic aorta was performed in all patients. Transcranial Doppler was used to measure cerebral embolic rates. Standardized neuropsychological testing was conducted 1 week before and 6 weeks after surgery. The raw scores for each test were converted to Z scores, and then a combined Z score of 10 main variables was calculated for both study groups. The primary analysis was based on dichotomous composite cognitive outcome with a 1-SD rule. Cognitive dysfunction was present in 6% (95% confidence interval, 1.3% to 10.7%) of patients in the cell saver group and 15% (95% confidence interval, 8% to 22%) of patients in the control group 6 weeks after surgery (Pϭ0.038). The severity of aortic atheroma and cerebral embolic count were similar between the 2 groups. Conclusions-The present report demonstrates that processing of shed blood with cell saver results in clinically significant reduction in postoperative cognitive dysfunction after cardiac surgery. These findings emphasize the clinical importance of lipid embolization in contributing to postoperative cognitive decline in patients exposed to cardiopulmonary bypass.

Early benefit of preserved cognitive function is not sustained at one-year after cardiac surgery: a longitudinal follow-up of the randomized controlled trial

“…[5][6][7][8] Recently, we showed that processing of shed blood with a continuous-flow cell saver during CPB resulted in a clinically significant reduction in POCD six weeks after surgery. 4 The reduced cognitive decline in the cell saver group was likely attributed to the lower lipid cerebral embolic load and the modified systemic inflammatory response with the application of cell saver.…”

“…4 Briefly, the continuousflow cell saver (Fresenius Corporation, Concord, CA, USA) was used to process shed blood before returning it back to the patient, and cardiotomy suction was used in a standard closed venous reservoir where cardiotomy blood was collected and reinfused through the arterial circuit back to the patient. Both the cell saver and the cardiotomy suction were used during the same time periods, i.e., from the time full heparinization (ACT [ 400 sec) was established to after the initial dose of protamine was given.…”

“…4 In brief, to estimate the change in performance from baseline to one year after surgery, the raw scores for each test were converted to Z-scores. A Z-score was calculated for each main variable in each patient by subtracting the preoperative score from the postoperative score and dividing the difference by the preoperative standard deviation of that variable.…”

“…4 Comparability of both groups was tested with the use of Chi square statistics or Fisher's exact test on qualitative variables, as appropriate, and the Student's t test on quantitative variables. For the primary analysis of dichotomous cognitive outcome, a sum of the individual Z-scores (a combined Z-score) of the ten main variables was compared between the two groups with a Chi square test.…”

“…Cerebral embolization, systemic inflammatory response, and cerebral hypoperfusion are usually implicated as likely etiologic factors for short-term POCD after cardiac surgery. The incidence of short-term POCD varies among studies, but the reported rates are 46-53% at discharge 1,2 and 15-36% at six weeks 1,3,4 after coronary artery bypass graft (CABG) surgery. The presence of early POCD measured at hospital discharge has been shown to be a significant predictor of long-term cognitive dysfunction five years after surgery.…”