Feasibility, Acceptability, and Preliminary Effect of a Cognitive Training Intervention for Postoperative Cardiac Surgical Patients

Abstract

Postoperative cognitive dysfunction (POCD) is characterized by a decline in cognitive performance following anesthesia and surgery and is a major cause of morbidity and mortality in the postoperative period. Moreover, studies suggest that patients who develop POCD may be at higher risk for cognitive decline later in life. POCD is of critical importance in relation to independent living, need for care, personal and economic cost, and quality of life. The majority of studies to date examine risk factors, prevalence, and complications associated with POCD. There is a lack of effective intervention strategies being developed to promote improved cognitive processing in this patient population. The primary aim of this study was to examine the feasibility and acceptability of a cognitive training intervention (CTI) for postoperative cardiac surgical patient. Feasibility was examined by conducting an attrition analysis to compare percent of attrition between intervention and control groups. A chi-square was conducted to answer the research question examining the difference between groups on attrition from study. Acceptability was examined by the administration of a "feasibility and acceptability" questionnaire, which was a 15-item questionnaire specific to the intervention. Fifteen one-sample t tests were used to determine acceptability of the intervention in the treatment population. The secondary purpose of the study was to investigate the preliminary effect of the CTI on cognitive outcomes following cardiac surgery. A randomized controlled, single-blind, repeated measures design was used to test the hypothesis that following cardiac surgery, patients who receive a 6-week CTI when compared with those who receive usual care will demonstrate a significantly greater improvement in cognitive status when comparing discharge scores to scores at 6 weeks and 3 months postoperatively. Collection of data from 53 patients who underwent cardiac surgery was conducted from May 2008 to January 2010 at Catholic Medical Center in Manchester, NH. Factorial Analyses of Variance were conducted to answer the research question assessing the effectiveness of a cognitive training intervention (CTI) on cognitive outcomes following cardiac surgery. However given assumptions of ANOVA were violated and non parametric statistics including two Kruskall Wallis H tests for independent samples at each assessment period as well as two Wilcoxon's signed ranks tests for related samples for each group were conducted. The results of the chi-square were not significant, x2(1) = 0.95, p = .329, suggesting no relationship exists between withdrawn participants and group. After Bonferroni adjustment the results of the fifteen one-sample t tests on the feasibility questionnaire (Q1-Q15) for the intervention group reveal questions 2-8, 10, 14 and 15 have a larger mean compared to the neutral median value of 3.0, suggesting that participants tended toward a high level of acceptability over neutrality. Wilcoxon signed rank test on TICS scores by control group and time period (posttest vs. six week follow up and posttest vs. three month follow up) revealed a significant main effect by time period, p< .01 at both time periods. Wilcoxon signed rank test on TICS scores by experimental group and time period (posttest vs. six week follow up and posttest vs. three month follow up) revealed a significant main effect by time period, p< .01 at both time periods. Kruskall Wallis test at six week follow up and three month follow up by group (control vs. experimental) was not significant, x2 (1) = 0.01, p = .934, and x2 (1) = 0.02, p = .891 respectively suggesting no statistical difference at six week follow up by group. The Wilcoxon signed rank on TICS by group and time period (six week follow up vs. 3 month follow up) was not significant (p=.274) and the Kruskall Wallis test at three month follow up by group (control vs. experimental) was not significant, x2 (1) = 0.02, p = .891, suggesting no statistical difference at three month follow up by group. The results of this study suggest that a CTI is feasible to conduct and acceptable to patients following cardiac surgery. Results of the preliminary effect of the CTI suggest that cognitive performance improves over a six-week period following cardiac surgery independent of the CTI and there are no significant changes from the six-week to the three-month period. Preliminary findings yield further inquiry into cognitive enhancing interventions in the cardiac surgical patient.