Efficacy of repetitive transcranial magnetic stimulation in preventing postoperative delirium in elderly patients undergoing major abdominal surgery: A randomized controlled trial.

Background: Postoperative delirium (POD) is a serious complication in elderly patients after major surgery, associated with high morbidity and mortality. Treatment and prevention methods are limited. Repetitive transcranial magnetic stimulation (rTMS) shows potential in enhancing cognitive function and improving consciousness.

Objective: To evaluate whether early postoperative rTMS has a protective effect against POD and to explore its potential mechanisms.

Methods: Patients aged 60 years or older, scheduled for major abdominal surgery, were randomly assigned to receive rTMS at 100 % RMT, 10 Hz, with 2000 pulses targeting the DLPFC after extubation in PACU, either as active rTMS(n = 61) or sham rTMS (n = 61). The primary outcome was the incidence of POD during the first 3 postoperative days.

Results: In the modified intention-to-treat analysis of 122 patients (mean [SD] age, 70.2 [4.1] years; 53.3 % women), POD incidence was lower in the rTMS group (11.5 %) compared to the sham rTMS group (29.5 %) (relative risk, .39; 95 % CI, .18 to .86; P = .01). rTMS patients had higher BDNF (8.47 [2.68] vs. 5.76 [1.42] ng/mL; P < .001) and lower NfL (.05 [.04] vs. .06 [.04] ng/mL; P = .02) levels. Mediation analysis suggests that rTMS may reduce POD by increasing brain-derived neurotrophic factor (z = -3.72, P < .001) rather than decreasing neurofilament light (z = 1.92, P = .06).

Conclusions: Immediate postoperative rTMS can reduce the incidence of POD in elderly patients undergoing major abdominal surgery, probably by upregulating brain-derived neurotrophic factor levels.