Effects of controlled low central venous pressure on cerebral blood flow in patients undergoing open hepatectomy / 中华麻醉学杂志

ABSTRACT

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.