Clinical Observation Of The Diameter Of Optic Nerve Sheath Effected By Dexmedetomidine In Patients Undergoing Laparoscopic Rectal Cancer Surgery

Objective:This study aims to investigate the changes in the optic nerve sheath diameter(ONSD)of patients undergoing laparoscopic rectal cancer surgery under general anesthesia with or without dexmedetomidine,thus to reflect the change of ICP under the application of carbon dioxide pneumoperitoneum and Trendelenburg position in the surgery,and explore the effects of dexmedetomidine on this change.Methods:A total of Sixty patients undergoing laparoscopic rectal cancer surgery were enrolled,randomly divided into two groups of 30 people each.Routing monitoring and induction of anesthesia were performed after admission.The experimental group(group D)was performed with 1 ?g / kg of dexmedetomidine within 10 minutes as loading dose at the start of anesthesia induction,and then continuously infused at a rate of 0.5 ?g / kg / h.Normal saline was administered at the same rate in the control group(Group P).The dexmedetomidine or saline was not stopped until 40 minutes before the end of operation.Anesthesia was maintained by continuous infusion of propofol combined with remifentanil.The ONSD,heart rate and mean arterial pressure were measured and recorded at 10 minutes after admission in the operating room(T0),30 minutes after adjusting to Trendelenburg position(T1),10 minutes before returning to supine position for the first time(T2),10 minutes before returning to supine position for the second time(T3),and before leaving the operating room(T4).Results:(1)Demographics date: the age,sex,height,weight,BMI,mean arterial pressure,heart rate,operation time,and basic ONSD value of the two groups were not statistically significant(all P>0.05).(2)ONSDs at T1-T4 were significantly increased compared to T0 in both groups(all P<0.05).(3)ONSDs at T1-T3 were significantly smaller in Group D then in Group P(5.26±0.12 vs 5.18±0.15,5.37±0.14 vs 5.22±0.15,5.30±0.13 vs 5.16±0.16,all P<0.05).There was no statistical difference between the two groups of ONSD values at T4(5.07±0.14 vs 5.01±0.14,P=0.096).Conclusion:The ONSD of patients undergoing the laparoscopic rectal cancer surgery was significantly increased since applying CO2 pneumoperitoneum and Trendelenburg position.And the last measured of ONSD before leaving the operating room did not return to the basic level.The administration of dexmedetomidine during surgery can attenuated the increase of ONSD,suggesting that dexmedetomidine may effectively attenuate the increase of ICP caused by the Trendelenburg position and pneumoperitoneum.