OBJECTIVE: To explore the effects of dexmedetomidine on postoperative delirium in elderly patients undergoing radical mastectomy. METHODS: Totally 120 elderly female patients undergoing radical mastectomy with general anesthesia from Sept. 2018 to Mar. 2020 were extracted to be divided into the control group and the dexmedetomidine group via the random number table

with 60 cases in each group. Patients in the dexmedetomidine group received intravenous pumping of dexmedetomidine 15 min before induction of anesthesia

with loading dose of0. 5 μg/kg

and then intravenous pumping at the rate of 0. 4 μg/（ kg·h） was given until 30 min before the end of the surgery. In the control group

0. 9% sodium chloride injection was injected intravenously at the same rate and volume.After surgery

both groups received patient-controlled intravenous analgesia（ PCIA） pump with sufentanil. The dexmedetomidine group was given sufentanil + dexmedetomidine for PCIA

while the control group only received sufentanil. Sleep scores

activity and resting visual analogue scale（ VAS） scores

occurrence and duration of delirium were recorded after surgery of 2 h

4 h

6 h

1 d

2 d and 3 d in both groups. RESULTS: After surgery of 6 h

1 d

2 d and 3 d

VAS score and sleep score at resting and active time in the dexmedetomidine group were significantly lower than those in the control group

with statistically significant difference（ P<0. 05）. The incidence of delirium in the dexmedetomidine group was 10%（ 6/60） and the average duration was（ 0. 8±0. 3） d; the incidence of delirium in the control group was 30%（ 18/60） and the average duration was（ 2. 5±0. 6） d; compared with the control group

the incidence of delirium in the dexmedetomidine group was significantly lower

and the duration was significantly shorter

the differences were statistically significant（ P < 0. 05）. Compared with the control group

there was no statistical significance in the incidence of postoperative hypoxemia

bradycardia

hypotension and other adverse reactions in the dexmedetomidine group（ P > 0. 05）. CONCLUSIONS: Dexmedetomidine administration during perioperative period can reduce the occurrence and severity of postoperative delirium.