title: Perfusion index as a possible predictor for postanesthetic shivering.
abstract: BACKGROUND
  Postanesthetic shivering can be triggered by surgical stress and several aspects of anesthetic management and is frequently preceded by a decrease in peripheral blood flow due to thermoregulatory vasoconstriction. As perfusion index correlates with peripheral blood flow, we examined whether perioperative perfusion index, measured using pulse oximetry, might be correlated with postanesthetic shivering.
  
  
  METHODS
  Twenty-eight patients presenting for elective abdominal surgery were enrolled. Core (esophagus) and peripheral (finger) temperatures and perfusion index were recorded in the perioperative periods. Correlations between perfusion index and peripheral temperature and core-to-peripheral temperature gradient were then explored. Plasma levels of epinephrine and norepinephrine were also measured. The extent of shivering was graded after emergence from anesthesia.
  
  
  RESULTS
  Perfusion index declined before emergence from anesthesia in patients who then developed postanesthetic shivering. This coincided with the time at which the difference between core and peripheral temperature became dissociated and peripheral temperature declined. Perioperative perfusion index was correlated with peripheral temperature and peripheral-core temperature gradient. Perfusion index at closure of the peritoneum predicted postanesthetic shivering and was significantly correlated with the extent of shivering. Plasma levels of both epinephrine and norepinephrine were significantly elevated after shivering events.
  
  
  CONCLUSIONS
  Perfusion index was significantly lower in patients with postanesthetic shivering before emergence from anesthesia, indicating that measurement of perfusion index during and before the end of anesthesia might be a useful means of predicting postanesthetic shivering.
authors.affiliation: Department of Anesthesiology and Critical Care Medicine, Graduate School of Medical and Dental Sciences, Kagoshima University, 8-35-1 Sakuragaoka, Kagoshima, 890-8520, Japan.
authors.forename: Chiharu
authors.initials: C
authors.lastname: Kuroki
authors.forename: Kohei
authors.initials: K
authors.lastname: Godai
authors.forename: Maiko
authors.initials: M
authors.lastname: Hasegawa-Moriyama
authors.forename: Tamotsu
authors.initials: T
authors.lastname: Kuniyoshi
authors.forename: Akira
authors.initials: A
authors.lastname: Matsunaga
authors.forename: Yuichi
authors.initials: Y
authors.lastname: Kanmura
authors.forename: Tomoyuki
authors.initials: T
authors.lastname: Kuwaki
mesh_terms: D000328:Adult; D000368:Aged; D000758:Anesthesia / Q000009:adverse effects*; D000777:Anesthetics / Q000009:adverse effects* / Q000494:pharmacology; D004837:Epinephrine / Q000097:blood; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009638:Norepinephrine / Q000097:blood; D010092:Oximetry / Q000379:methods; D012768:Shivering / Q000187:drug effects*; D014661:Vasoconstriction / Q000187:drug effects
chemical_list: D000777:Anesthetics; D009638:Norepinephrine; D004837:Epinephrine