Abstract: Objective To investigate the effects of pre-administration of mannitol on optic nerve sheath diameter and postoperative recovery quality in patients undergoing robot-assisted laparoscopic radical resection of rectal cancer.Methods Seventy patients undergoing laparoscopic radical resection of rectal cancer under general anesthesia in our hospital were enrolled and randomly divided into two groups:mannitol group(group G) and control group(group C)，35 cases in each.The patients in group G were infused with 20% mannitol 0.5g/kg within 30 minutes after pneumoperitoneum(PP),and the patients in group C were infused with the same amount of normal saline at the same time point.The optic nerve sheath diameter was compared between the two groups at 1 min after intubation (T0), 5mins after pneumoperitoneum (T1), 30mins after pneumoperitoneum (T2), 60mins after pneumoperitoneum (T3), 90mins after pneumoperitoneum (T4), 10mins after surgery (T5) and differences in optic nerve sheath diameter and quality of resuscitation.Results The ONSDs of group G at T2-T4 were(4.27±0.19)mm,(4.48±0.19)mm and (4.54±0.19)mm,respectively,which were bigger than ONSD at T0 [(4.04±0.17)mm,P＜0.05].The ONSDs of group C at T2-T4 were (4.38±0.26)mm,(4.66±0.28)mm and(4.90±0.26)mm,respectively,which were bigger than ONSD at T0 [(4.00±0.23)mm,P＜0.05].There were significant differences in ONSDs between group G and group C at T3 and T4 [(4.48±0.19)mm vs (4.66±0.28)mm,P＜0.05;(4.54±0.19)mm vs (4.90±0.26)mm,P＜0.05].The recovery time,extubation time and PACU time in group G were (20.34±6.38)min,(26.69±6.54)min,(48.74±11.40)min,which were respectively shorter than those in group C [(47.71±10.57)min,(48.77±12.28)min and (76.74±12.57)min,P＜0.05].OAAS score at 30min after extubation in group G was significantly higher than that in group C [(4.43±0.66) vs (2.80±0.99),P＜0.05].Agitation score at 30min after extubation in group G was significantly lower than that in group C [(0.80±0.58) vs (1.63±0.84),P＜0.05].The incidences of headache and eye pain in group G was both lower than those in group C(2.9% vs 17.1%,P＜0.05;5.7% vs 25.7%,P＜0.05).Cnclusiono Pre-administration of mannitol can prevent the increase of ONSD,improve the recovery quality and reduce the incidence of adverse reactions.

Key words: optic nerve sheath diameter, robot, mannitol, radical resection of rectal cancer