Intraoperative electroencephalographic marker of preoperative frailty: A prospective cohort study

Abstract

Trial registration: ClinicalTrials.gov NCT04783662.

Keywords: Clinical frailty scale; Electroencephalography; Frailty; Fried phenotype; Intraoperative; Surgery.

Fig. 1.

Time periods of EEG Data analysis. Depiction of the surgical timeline with emphasis in the three periods in which collected EEG data were obtained. The first period was a closed-eye resting state baseline period during wakefulness. The second one was a pre-surgery period that was obtained 10 min after induction and intubation but mostly before the start of surgery. The third analyzed period, post-surgery period, was obtained 10 min before anesthesia ceased (turn-off volatile agent).

Fig. 2.

Cohort flowchart. A total of 587 patients were screened from the elective non-cardiac surgical schedule at our institution. We recruited 62 patients that gave written informed consent to participate. 60 of them completed perioperative assessments. Adequate EEG data collection was achieved in 52 cases in baseline, 58 cases pre-surgery, and 55 cases post-surgery. One patient did not receive CAM-ICU evaluation in PACU because he was derived to the ICU.

Fig. 3.

GBT classification performances for Fried phenotype (non-frail ≤ 2 points vs. frail ≥ 3 points). (A) The out-of-sample AUC for Fried phenotype, using covariates (red), EEG (black), and covariates and EEG combined (blue), at different EEG recording times. The error bar represents 95% confidence interval from bootstrapping. The dashed horizontal line indicates chance AUC value at 0.5. (B,C,D) The ROCs for every condition. The x-axis is the false positive rate (FPR). The y-axis is the true positive rate (TPR). The curve represents FPR and TPR as a function of threshold applied to the probabilistic output. The shaded area represents the 95% confidence interval. The diagonal dashed red line represents chance level ROC. The AUCs are shown in the legend which are consistent with the numbers in panel A. I The out-of-sample Cohen’s kappa for Fried phenotype, using covariates (red), EEG (black), and covariates and EEG combined (blue), at different EEG recording times. The error bar represents 95% confidence interval from bootstrapping. The dashed horizontal line indicates chance Cohen’s kappa value at 0. Different than AUC, Cohen’s kappa adjusts for imbalanced non-frail vs. frail ratio in the dataset. (For interpretation of the references to colour in this figure legend, the reader is referred to the web version of this article.)

Fig. 4.

GBT classification performances for CFS (non-frail ≤ 3 points vs. frail ≥ 4 points). Organized similarly as in Fig. 3, but for CFS.