Abstract:Objective To investigate the effect of depth of anesthesia on postoperative pain after laparoscopic cholecystectomy. Methods Sixty patients undergoing laparoscopic cholecystectomy were randomly divided into two groups: low bispectral index group (L-BIS = 35 to 44) and high bispectral index group (H-BIS = 45 to 55), anesthesia induction and maintenance protocol was the same for both groups, and the depths of anesthesia was controlled in different levels. We evaluated VAS score (at rest and during cough) at recovery (0), 8th, 16 and 24th hours after operation and recorded the mean dose of using remedial analgesic within 24 hours, the condition of post-operative nausea and vomiting (PONV), the condition of patients’ satisfaction. Results The VAS scores of patients in the L-BIS group at rest and cough were lower than those in the H-BIS group. The number of patients requiring additional analgesics during recovery in the H-BIS group was greater than in the L-BIS group (P?0.05). The incidence of nausea and vomiting in the L-BIS group was lower than that in the H-BIS group at 24?h after operation (P?0.05). The postoperative analgesia satisfaction in the L-BIS group was higher than that in the H-BIS group (P?0.05). Conclusions General anesthesia with propofol and remifentanil with L-BIS causes less need for additional analgesic drug, less nausea and vomiting and higher postoperative analgesia satisfaction of the patients compared to anesthesia with H-BIS.