title: A survey of the dose of inhalational agents used to maintain anaesthesia in infants.
abstract: BACKGROUND
  Various animal studies suggest that currently used anaesthetics are toxic to the developing brain. Many reviews advise that the total anaesthetic drug exposure should be reduced but the dose usually used in clinical practice has not been clearly elucidated.
  
  
  OBJECTIVE
  To provide an overview of the dose ranges currently used in clinical practice during the maintenance phase of anaesthesia in infants undergoing anaesthesia for noncardiac surgery and diagnostic procedures.
  
  
  METHODS
  A two-centre mixed prospective (London) and retrospective (Utrecht) observational cohort study.
  
  
  METHODS
  Two independent tertiary paediatric referral centres in March and November 2013; Great Ormond Street Hospital (GOSH), London, United Kingdom and Wilhelmina Children's Hospital, University Medical Center Utrecht (UMCU), The Netherlands.
  
  
  METHODS
  A total of 76 infants were included in the analysis, 38 infants from each hospital.
  
  
  METHODS
  Patients from GOSH were matched by procedure, age and weight with patients from the UMCU. The end-tidal concentrations of the inhalational agents were investigated from anaesthetic charts during the maintenance phase and corrected for the age-specific minimal alveolar concentration (MAC), expressed as a percentage from the MAC (%MAC).
  
  
  RESULTS
  Three different types of inhalational anaesthetics were used: sevoflurane, desflurane, isoflurane. The mean %MAC was 0.85. No significant differences in %MAC were found between GOSH and the UMCU (P = 0.329); the mean %MAC in GOSH was 0.87 and in the UMCU was 0.82. There was a significant increase in the %MAC in relation to age (slope = 0.036 MAC month, P < 0.001). Of all patients, 75% had an end-tidal concentration lower than 1 MAC. There was no significant effect of the use of analgesia on the end-tidal concentration of inhalational anaesthetics (P = 0.366).
  
  
  CONCLUSIONS
  The concentration of inhalational anaesthetics in %MAC increased with age and was lowest in neonates. Most young infants received inhalational anaesthetics at a concentration below 1 MAC, which accords with current guidance to minimise anaesthetic drug exposure but may have unintended consequences.
authors.affiliation: From the Department of Anaesthesiology (ENB, LvW, JCdG); Department of Neonatology, Wilhelmina Children's Hospital, University Medical Center Utrecht, Utrecht, The Netherlands (ENB, LJS, PMAL); Department of Paediatric Anaesthesiology, Great Ormond Street Hospital, NHS, London (LJS, MRS); University of Glasgow, Glasgow, United Kingdom (PP); and Department of Anaesthesiology, Sophia Children's Hospital, Erasmus Medical Center Rotterdam, Rotterdam, The Netherlands (JCdG).
authors.forename: E Noor
authors.initials: EN
authors.lastname: Brinkman
authors.forename: Lisanne J
authors.initials: LJ
authors.lastname: Stolwijk
authors.forename: Petra M A
authors.initials: PM
authors.lastname: Lemmers
authors.forename: Leo
authors.initials: L
authors.lastname: van Wolfswinkel
authors.forename: Paul
authors.initials: P
authors.lastname: Purvis
authors.forename: Mike R
authors.initials: MR
authors.lastname: Sury
authors.forename: Jurgen C
authors.initials: JC
authors.lastname: de Graaff
mesh_terms: D000367:Age Factors; D000769:Anesthesia, Inhalation / Q000379:methods*; D018685:Anesthetics, Inhalation / Q000008:administration & dosage* / Q000378:metabolism; D015331:Cohort Studies; D004305:Dose-Response Relationship, Drug; D005260:Female; D006801:Humans; D007223:Infant; D007231:Infant, Newborn; D008297:Male; D011446:Prospective Studies; D011650:Pulmonary Alveoli / Q000187:drug effects* / Q000378:metabolism; D012189:Retrospective Studies; D011795:Surveys and Questionnaires
chemical_list: D018685:Anesthetics, Inhalation