The Effect of Low-Dose Esketamine on Postoperative Neurocognitive Dysfunction in Elderly Patients Undergoing General Anesthesia for Gastrointestinal Tumors: A Randomized Controlled Trial

PURPOSE: This study aims to evaluate the effects of the intraoperative application of low-dose esketamine on postoperative neurocognitive dysfunction (PND) in elderly patients undergoing general anesthesia for gastrointestinal tumors. METHODS: Sixty-eight elderly patients were randomly allocated to two groups: the esketamine group (group Es) (0.25 mg/kg loading, 0.125mg/kg/h infusion) and the control group (group C) (received normal saline). The primary outcome was the incidence of delayed neurocognitive recovery (DNR). The secondary outcomes were intraoperative blood loss, the total amount of fluid given during surgery, propofol and remifentanil consumption, cardiovascular adverse events, use of vasoactive drugs, operating and anesthesia time, the number of cases of sufentanil remedial analgesia, the incidence of postoperative delirium (POD), the intraoperative hemodynamics, bispectral index (BIS) value at 0, 1, 2 h after operation and numeric rating scale (NRS) pain scores within 3 d after surgery. RESULTS: The incidence of DNR in group Es (16.13%) was lower than in group C (38.71%) (P <0.05). The intraoperative remifentanil dosage and the number of cases of dopamine used in group Es were lower than in group C (P <0.05). Compared with group C, DBP was higher at 3 min after intubation, and MAP was lower at 30 min after extubation in group Es (P<0.05). The incidence of hypotension and tachycardia in group Es was lower than in group C (P <0.05). The NRS pain score at 3 d after surgery in group Es was lower than in group C (P <0.05). CONCLUSION: Low-dose esketamine infusion reduced to some extent the incidence of DNR in elderly patients undergoing general anesthesia for gastrointestinal tumors, improved intraoperative hemodynamics and BIS value, decreased the incidence of cardiovascular adverse events and the intraoperative consumption of opioids, and relieved postoperative pain.