Effects of different depths of anesthesia on hemodynamic stability and anesthesia recovery in the elderly undergoing elective laparoscopic surgery for colorectal cancer

Objective To investigate the effects of three different depths of anesthesia on hemodynamic changes and anesthesia recovery undergoing elective surgery in the elderly.Methods 150 ASA Ⅰ-Ⅲ patients＞60 years undergoing elective laparoscopic surgery for colorectal cancer with general anesthesia were randomized into 3 groups of group A [anesthesia depth maintained with the target of narcotrend index(NI)at Do level],group B (NI at D2 level) and group C (NI at E1 level).Anesthetics (propofol and remifentanil) were adjusted according to the narcotrend monitoring results to keep the depth of anesthesia in the preset target level.The hemodynamic changes at different time points,anesthetic consumption,the patients' condition during anesthesia recovery and adverse reaction were recorded.Results The patients' mean artery pressure (MAP) and heart rate (HR) in group A were markedly increased after tracheal intubation,2 min after artificial pneumoperitoneum,end of the surgery and during extubation (P＜0.05).The patients' MAP of the three groups were all significantly decreased 2 min after the anesthesia induction and 2 min before artificial pneumoperitoneum (P＜0.05 or P＜0.01).The patients' MAP of group C was significantly lower than that of group A and group B 2 min after anesthesia induction and 2 min before artificial pneumoperitoneum (P＜0.05).The incidence of hypertension was 31.3％ in group A,which was significantly higher comparing to group B (14.6％) and group C (12.2％)(P＜0.05).And the incidence of hypotension was apparently higher in group C (40.8％) than that of group A (12.5％) and group B (18.8％)(P＜0.01).The propofol consumption of group C[(1 637±423) mg] was much more than that of group A and group B[(1 136±378) mg and (1 217±366) mg respectively] (P＜0.05),and the recovery times(eye opening time and extubation time) were significantly longer in group C [(14.8±1.3),(19.2±4.8) min] comparing to group A[(7.2±1.4),(10.0±3.3) min]and group C [(8.1±1.1),(11.8±2.6) min] (P＜0.01).Conclusions It's best to maintain the depth of anesthesia at the target of NI at D2 level in the elderly undergoing laparoscopic surgery for colorectal cancer,which is more helpful to gain hemodynamic stability without increasing anesthetic consumption and delayed recovery. Key words: Depth of anesthesia;  Narcotrend;  Elderly;  Monitoring