Effects of different sufentanil target concentrations on the MACBAR of sevoflurane in patients with carbon dioxide pneumoperitoneum stimulus
Abstract Background:The objective of this study is to observe the effects of different target controlled plasma sufentanil concentrations on the minimum alveolar concentration (MAC) of sevoflurane for blocking adrenergic response (BAR) in patients undergoing laparoscopic cholecystectomy with carbon dioxide pneumoperitoneum stimulation.Methods: Eighty-five patients undergoing laparoscopic cholecystectomy, aged 18-65 years, with American Society of Anaesthesiologists physical status Ⅰ-Ⅱ, were enrolled in this study. All the patients were randomly divided into 5 groups (S0, S1, S2, S3, S4) with different sufentanil plasma target concentration (0.0, 0.1, 0.3, 0.5, 0.7 ng ml-1). Anaesthesia was induced by inhalation of 8% sevoflurane in 100% oxygen, and 0.6 mg kg-1 of rocuronium was intravenously injected to facilitate the insertion of laryngeal mask airway. The end-tidal sevoflurane concentration and sufentanil plasma target concentration were adjusted according to respective preset value in each group. The hemodynamic response to pneumoperitoneum stimulus was observed after the end-tidal sevoflurane concentration had been maintained stable at least for 15 min. The MACBAR of sevoflurane was measured by a sequential method. Meanwhile, epinephrine and norepinephrine concentrations in the blood were also determined before and after pneumoperitoneum stimulus in each group.Results:The basic MACBAR of sevoflurane in group S0 was 5.33% (confidence interval[CI] 95%: 5.19-5.47%), which was decreased 15%, 46%, 58% and 60% by the infusion of sufentanil with 0.1, 0.3, 0.5 and 0.7 ng ml-1 plasma target concentration, respectively. But the decreased degree had no significant difference between 0.5 and 0.7 ng ml-1 of sufentanil plasma target concentrations. No significant difference was found in the change of epinephrine or norepinephrine concentration between before and after pneumoperitoneum stimulation in each group.Conclusions: The MACBAR of sevoflurane can be decreased with increasing sufentanil plasma target concentrations. A capping effect of the decrease occurred at a sufentanil plasma target concentration of 0.5 ng ml-1. When the sympathetic adrenergic response was inhibited in half patients to pneumoperitoneum stimulation in each group, the changes of epinephrine and norepinephrine concentrations showed no significant differences.Trial registration: The study was registered at http://www.chictr.org.cn (ChiCTR1800015819, 23, April, 2018) .