Objective:To evaluate the effects of controlled low central venous pressure (CLCVP) on the cerebral blood flow in the patients undergoing open hepatectomy.Methods:Thirty American Society of Anesthesiologists Physical Status classification Ⅱ or Ⅲ patients of either sex, aged 18-60 yr, with body mass index of 18-30 kg/m 2, with Child-Pugh classification A and expected operation time of 2-4 h, undergoing elective open hepatectomy, were enrolled.After anesthesia induction, patients were placed at head-up tilt position, nitroglycerin 0.5-1.5 μg·kg -1·min -1 was infused, and furosamide 5-10 mg was intravenously injected when necessary to maintain CVP less than 5 cmH 2O during hepatectomy.After the end of hepatectomy, CLCVP was stopped, the infusion rate was increased to 10 ml·kg -1·h -1 with a crystalline gel ratio of 1∶2 to restore CVP to more than 5 cmH 2O.At 5 min after anesthesia induction (T 0), 5 min after head-up tilt (T 1), 5 and 15 min after CVP reaching the target (T 2, 3) and 5 min after the end of CLCVP (T 4), the blood flow of internal carotid artery was detected by ultrasound, and peak systolic velocity(IBVs), end diastolic velocity (IBVd)and vessel diameter of the internal carotid artery (ID)were measured by doppler ultrasound.Mean velocity [IBVm=(IBVs+ IBVd×2)÷3] and internal carotid artery blood flow [IBF=IBVm×π×(ID/2) 2×HR] were calculated.Heart rate (HR), mean arterial blood pressure (MAP), cardiac output (CO), stroke volume (SV), end-tidal pressure of carbon dioxide (P ETCO 2) and maximum airway pressure (P max) were recorded at each time point. Results:Compared with the baseline at T 0, MAP, CO, SV, IBVm and IBF were significantly decreased at T 2, 3 ( P<0.001), and no significant change was found in HR, P ETCO 2 and P max at T 1-4 ( P>0.05). The results of linear mixed-effects model analysis showed that the regression coefficients for CO, MAP, HR, and SV were 0.600 3, 0.022 88, 0.363 7, and 0.614 8, respectively ( P<0.05 or 0.01). Conclusions:CLCVP can decrease the cerebral blood flow in the patients, which is closely associated with decreased CO, MAP, HR and SV when used for open hepatectomy.

Objective:To evaluate the effect of preoperative oral carbohydrate on gastric emptying in the patients undergoing laparoscopic cholecystectomy.Methods:One hundred patients of both sexes, aged 18-64 yr, with body mass index of 18-30 kg/m 2, of American Society of Anesthesiologists physical status Ⅰ or Ⅱ, were divided into 2 groups ( n=50 each) using the random number table method: control group (group C) and preoperative oral carbohydrate group (group P). Patients underwent solid food fasting after 20: 00 on the night before surgery in both groups and drinking fasting after 21: 30 on the night before surgery in group C. Group P received 800 ml of 12.5% oral carbohydrate at 21: 30 on the night before surgery and 400 ml of oral similar carbohydrate from 5: 00 to 5: 30 in the morning before surgery.All the patients underwent ultrasound examination of the gastric sinus at 7: 30 on the operation day (2 h after oral carbohydrate, T 1) to determine the nature of gastric contents according to the qualitative analysis of images, and Perlas grade was performed, and the cross-sectional area (CSA) of the gastric sinus in a semi-sitting position and right lateral decubitus position was calculated, and gastric volume (GV) and gastric volume to weight ratio (GV/W) were calculated.For solids in the stomach or GV > 1.5 ml/kg was defined as a full stomach.Patients assessed as a full stomach at T 1 underwent antrum ultrasonography again before induction of anesthesia (at 3 h after oral carbohydrate, T 2). The occurrence of satiety at T 1 and T 2 in each group was recorded.The patient′s hunger score, thirst score, and satisfaction score during fasting were recorded at T 2.The reflux aspiration, occurrence of nausea and vomiting at 24 h after operation, postoperative time to first flatus and postoperative total length of hospital stay were recorded. Results:Compared with group C, the CSA in a semi-sitting position, CSA, GV and GV/W ratio in a right lateral decubitus position, incidence of satiety, and Perlas grade were significantly increased at T 1 ( P<0.05), no significant change was found in the incidence of satiety at T 2 ( P>0.05), preoperative hunger and thirst scores were significantly decreased, satisfaction scores were increased, the incidence of nausea and vomiting was decreased at 24 h after surgery, and the postoperative time to first flatus was shortened ( P<0.05), and no significant change in the postoperative total length of hospital stay was found in group P ( P>0.05). Conclusions:Oral carbohydrates before laparoscopic cholecystectomy may result in delayed gastric emptying in the patients with cholelithiasis, and the time window for oral carbohydrates can be appropriately shifted forward (3 h before surgery).