title: Sevoflurane requirement to maintain bispectral index-guided steady-state level of anesthesia during the rewarming phase of cardiopulmonary bypass with moderate hypothermia.
abstract: OBJECTIVE
  The authors aimed to quantify any increase and the extent of the increase in sevoflurane requirements for maintaining hypnosis during hypothermic cardiopulmonary bypass (CPB) with the bispectral index (BIS) maintained between 40 and 50.
  
  
  METHODS
  An observational prospective study.
  
  
  METHODS
  A single-center tertiary referral center at a university hospital.
  
  
  METHODS
  Fifty patients undergoing elective coronary artery bypass graft surgery with CPB.
  
  
  METHODS
  End-tidal oxygenator expiratory gas concentrations were used to quantify sevoflurane requirements while maintaining a BIS level between 40 and 50 during the rewarming phase.
  
  
  RESULTS
  Sevoflurane requirements progressively increased as temperature increased. The difference in sevoflurane requirement at 35°C and 29°C was compared using analysis of variance for repeated measures, which was statistically significant. When relating temperature and sevoflurane requirement, the Pearson correlation coefficient was 0.67. Linear regression analysis using temperature as the independent variable and expiratory sevoflurane as the dependent variable showed a temperature β-coefficient of 0.11 and a constant of -2.34. Other parameters like fresh gas flows and pump flows were correlated to find out if they affected end-tidal sevoflurane levels on CPB. They were not significant in multivariate analysis.
  
  
  CONCLUSIONS
  The sevoflurane requirement increases during the rewarming phase of hypothermic CPB. The percent increase in the requirement for sevoflurane is uniform and follows a particular pattern, which may be predicted.
authors: VIVUS-SMRC Heart Centre, Goa, India. dramoldivya@gmail.com
authors: Divya Amol
authors: DA
authors: Chandran Mahaldar
authors: Shrinivas
authors: S
authors: Gadhinglajkar
authors: Rupa
authors: R
authors: Sreedhar
mesh_terms: D000368:Aged; D018685:Anesthetics, Inhalation / Q000008:administration & dosage; D001831:Body Temperature / Q000187:drug effects / Q000502:physiology; D002315:Cardiopulmonary Bypass / Q000379:methods / Q000639:trends*; D004569:Electroencephalography / Q000379:methods / Q000639:trends*; D005260:Female; D006801:Humans; D007036:Hypothermia, Induced / Q000379:methods / Q000639:trends*; D008297:Male; D008738:Methyl Ethers / Q000008:administration & dosage*; D008875:Middle Aged; D016343:Monitoring, Intraoperative / Q000379:methods / Q000639:trends*; D011446:Prospective Studies; D017694:Rewarming / Q000379:methods / Q000639:trends*; D000077149:Sevoflurane
chemical_list: D018685:Anesthetics, Inhalation; D008738:Methyl Ethers; D000077149:Sevoflurane