Experience of using composite Z-score to assess delayed cognitive recovery in elderly patients who underwent surgery for colorectal cancer under intravenous or inhalation anesthesia. A prospective observational pilot study

Introduction. Perioperative cognitive disorders (POCD) represents a risk for elderly patients. Currently, there is no uniform and standardized methodology for the identification of POCD in the existing literature. Additionally, there is an ongoing debate regarding the optimal anesthetic option for geriatric patients. The objective was to compare the incidence of delayed cognitive recovery depending on the main component of anesthesia in patients operated for colorectal cancer using composite Z-scores. Materials and Methods. The study cohort comprised 31 patients who underwent surgical treatment for colorectal cancer under inhalation or intravenous anesthesia. The inclusion criteria were as follows: age over 60 years, planned surgical intervention of more than 180 minutes, absence of neurodegenerative, psychiatric diseases, cerebrovascular accident (CVA), diabetes mellitus in the anamnesis, and compliance with ASA class II or III. Neuropsychological testing was conducted preoperatively and on the fourth or fifth postoperative day. Delayed cognitive recovery was defined as a decrease in the composite Z-score of more than one standard deviation (SD) in comparison to the preoperative assessment. Results. Delayed cognitive recovery in the group where sevoflurane was the main component exhibited in two patients (12.5%). In contrast, this complication was not observed in the group where propofol was the main component (p = 0.484). When using propofol, the delta of the composite Z-score was statistically significantly better – 0.306 [0.078; 0.484] than when using sevoflurane – –0.121 [-0.556; 0.022] (p = 0.001), which indicated a faster recovery of cognitive functions in the postoperative period. Conclusion. The results of neuropsychological tests on patients who underwent surgical interventions with propofol as the main component were more similar to the results of preoperative assessments. This suggests a faster recovery of cognitive function in the postoperative period.