title: To clarify features of photoplethysmography in monitoring balanced anesthesia, compared with Cerebral State Index.
abstract: BACKGROUND
  Although photoplethysmography and cerebral state index (CSI) have been used as indices in monitoring vital signs perioperatively, there are only a few reports comparing the performance of photoplethysmography with CSI in monitoring anaesthesia depth. The aim of the present study was to clarify features of photoplethysmography in monitoring balanced general anesthesia compared with CSI.
  
  
  METHODS
  Forty-five patients undergoing elective operation under general anaesthesia were enrolled in this study. Anaesthesia was induced with target-controlled infusion propofol. The photoplethysmogram, CSI, Modified Observer's Assessment of Alertness/Sedation Scale (MOAAS), and mean arterial pressure (MAP) were continuously monitored and recorded. Finger photoplethysmogram amplitude (PPGA) and pulse beat interval (PBI) were calculated off-line.
  
  
  RESULTS
  For the period of time from pre-induction to pre-intubation, the coefficient of correlation between MOAAS and CSI was higher than those between MOAAS and PPGA, PBI, and MAP. CSI showed higher prediction probabilities (Pk) to differentiate the levels of MOAAS than did PPGA, PBI, and MAP. PPGA, PBI, and MAP values showed significant differences between before and after intubation, as well as pre- and post-incision (P<0.05), but no significant changes in cerebral state index (P>0.05).
  
  
  CONCLUSIONS
  The present study shows that photoplethysmography-derived parameters appear to be more suitable in monitoring the nociceptive component of balanced general anesthesia, while CSI performs well in detecting the sedation or hypnotic component of balanced general anesthesia.
authors.affiliation: Department of Anesthesiology, Nanjing First Hospital, Nanjing Medical University, Nanjing, China (mainland).
authors.forename: Lieliang
authors.initials: L
authors.lastname: Zhang
authors.affiliation: Department of Anesthesiology, Nanjing First Hospital, Nanjing Medical University, Nanjing, China (mainland).
authors.forename: Lei
authors.initials: L
authors.lastname: Xu
authors.affiliation: Department of Anesthesiology, Nanjing First Hospital, Nanjing Medical University, Nanjing, China (mainland).
authors.forename: Juan
authors.initials: J
authors.lastname: Zhu
authors.affiliation: Department of Anesthesiology, Nanjing First Hospital, Nanjing Medical University, Nanjing, China (mainland).
authors.forename: Yujie
authors.initials: Y
authors.lastname: Gao
authors.affiliation: Department of Anesthesiology, Nanjing First Hospital, Nanjing Medical University, Nanjing, China (mainland).
authors.forename: Zhonghua
authors.initials: Z
authors.lastname: Luo
authors.affiliation: Department of Anesthesiology, Nanjing First Hospital, Nanjing Medical University, Nanjing, China (mainland).
authors.forename: Hongyu
authors.initials: H
authors.lastname: Wang
authors.affiliation: Department of Anesthesiology, Nanjing First Hospital, Nanjing Medical University, Nanjing, China (mainland).
authors.forename: Zhongliang
authors.initials: Z
authors.lastname: Zhu
authors.affiliation: Department of Anesthesiology, Nanjing First Hospital, Nanjing Medical University, Nanjing, China (mainland).
authors.forename: Yi
authors.initials: Y
authors.lastname: Yu
authors.affiliation: Department of Anesthesiology, Nanjing First Hospital, Nanjing Medical University, Nanjing, China (mainland).
authors.forename: Hongwei
authors.initials: H
authors.lastname: Shi
authors.affiliation: Department of Anesthesiology, Nanjing First Hospital, Nanjing Medical University, Nanjing, China (mainland).
authors.forename: Hongguang
authors.initials: H
authors.lastname: Bao
mesh_terms: D000328:Adult; D000368:Aged; D062186:Arterial Pressure / Q000502:physiology; D058126:Balanced Anesthesia / Q000379:methods*; D056805:Consciousness Monitors; D006801:Humans; D007440:Intubation; D008875:Middle Aged; D008991:Monitoring, Physiologic / Q000379:methods*; D017156:Photoplethysmography; D011674:Pulse; D018709:Statistics, Nonparametric; D055815:Young Adult