Comparison of blood pressure and pain rating index used for depth regulation of sevoflurane anaesthesia.

Abstract

The Pain Rating index (PRi) is a new parameter for regulating analgesic depth of anaesthesia based on wavelet analysis. The aim of this study was to investigate the feasibility of PRi for depth regulation of sevoflurane anaesthesia. We conducted a monocentric randomized controlled study from September 2017 to June 2018 in patients undergoing anterior cervical discectomy and fusion (ACDF) (n=44). Patients were randomly allocated into two groups and assigned 22 cases to each group: systolic blood pressure group (SBP group) and pain rating index group (PRi group). In SBP group, sevoflurane inhalation concentration (Cs) was adjusted to maintain SBP values at baseline values -20%～+20%; in PRi group, Cs was adjusted to maintain PRi values between 50 and 70. The primary endpoint was anaesthesia recovery time. Secondary endpoints included extubation time, sevoflurane consumption, number of intraoperative haemodynamic instability events /interventions, number of adverse events and postoperative visual analogue scale for pain. Patient demographic characteristics, surgical time and anaesthesia time did not differ between groups. Anaesthesia recovery time was shorter in PRi group than in SBP group (17.5±3.8min vs 21.5±2.8 min; P=0.001). Extubation time was also shorter in PRi group than in SBP group (21.9±1.7min vs 24.1±2.5min; P=0.001). Sevoflurane consumption was lower in PRi group than in SBP group (15.5±4.1ml vs 20.0±2.5ml; P=0.001). PRi was feasible to regulate depth of sevoflurane anaesthesia, which could shorten anaesthesia recovery time and extubation time, reduce sevoflurane consumption during general anaesthesia in patients undergoing cervical vertebra surgery.