Objective  To observe the effect of dexmedetomidine on optic nerve sheath diameter (ONSD)in patients undergoing gynecological laparoscopic surgery in Trendelenburg position.

  Methods  Sixty patients underwent laparoscopic total hysterectomy were selected as research objects. They were randomly divided into dexmedetomidine group (n=30) and control group (n=30). The dexmedetomidine group was continuous pumped 0.4 μg/(kg·h) dexmedetomidine from anesthesia induction until patients were restored to horizontal position and pneumoperitoneum was closed for 10 min, and the control group was pumped with 0.9 % sodium chloride solution in the same way. The ONSD, heart rate (HR) and mean arterial pressure (MAP) were measured at 5 min before induction of anesthesia (T₀) and 10 min (T₁), 30 min (T₂) as well as 60 min (T₃) at the low level of pneumoperitoneum head and 10 min after conversion to horizontal position and pneumoperitoneum closure (T₄) in the two groups. The incidence of nausea, vomiting and headache within 3 hours after operation was compared between the two groups.

  Results  The ONSD of the dexmedetomidine group was significantly less, and the HR was significantly lower than those of the control group at T₁, T₂, T₃ and T₄ (P < 0.05). The incidence rates of postoperative nausea and vomiting as well as headache within 3 hours after operation in the dexmedetomidine group were 20.00% and 13.33%, which were significantly lower than 46.67% and 40.00% in the control group (P < 0.05).

  Conclusion  The application of dexmedetomidine can effectively reduce the ONSD increase of patients undergoing gynecological laparoscopic surgery in Trendelenburg position, and reduce the incidence of postoperative nausea and vomiting as well as headache.