Comparison of finger photoplethysmogram and cerebral state index for monitoring depth of anaesthesia

ZHANG Lie-liang; HUA Fu-zhou; YING Jun; ZHANG Jing; ZHOU Bin; LUO Zhen-zhong; HU Yan-hui; XU Guo-hai

doi:10.3969/j.issn.1006-5725.2015.19.019

Abstract：Objective To explore the similarities and differences between finger photoplethysmogram (PPG) and CSI in monitoring the depth of anaesthesia in Chinese adults under general anaesthesia. Methods Ninety-three patients, ASA ⅠorⅡ, aged 20-67, under general anaesthesia were enrolled. Anaesthesia was induced with target-controlled infusion (TCI) of propofol. The initial TCI concentration of propofol was set at 0.5 mg·L-1 followed by increments of 0.5 mg·L-1 at 3-min interval until the score of Modified Observer's Assessment of Alertness/Sedation Scale (MOAAS)reached 0. PPG and CSI were continuously monitored and their values were recorded every 2-4 seconds. MOAAS was recorded every 30 seconds to evaluate the sedation level in the study period. ResultsFor the periodfrom pre-induction to pre-intubation, the difference of photoplethysmogram amplitudevalues had statistical significance between level 4 and level 3, level 3 and level 2 of MOAAS (P<0.05). CSIvalues declined along with the decrease of MOAAS levels and were statistically different between every two neighboring levels of MOAAS (P < 0.05). Photoplethysmogram amplitude (PPGA) and pulse beat interval (PBI) values showed significant differences before and after intubation, pre- and post-incision (P < 0.05). Conclusions PPGA and PBI appear to be suitable to monitor the nociceptive component of balanced general anesthesia , while the CSI exhibits a good performance in monitoring the sedation or hypnotic component of balanced general anesthesia , thusthe combination of PPGA and CSI would benefit the monitoring of the adequacy of depth of anaesthesia.