A survey of the dose of inhalational agents used to maintain anaesthesia in infants

BACKGROUNDVarious 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. OBJECTIVESTo 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. DESIGNA two-centre mixed prospective (London) and retrospective (Utrecht) observational cohort study. SETTINGTwo independent tertiary paediatric referral centres in March and November 2013; Great Ormond Street Hospital (GOSH), London, United Kingdom and Wilhelmina Childrenʼs Hospital, University Medical Center Utrecht (UMCU), The Netherlands. PATIENTSA total of 76 infants were included in the analysis, 38 infants from each hospital. METHODSPatients 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). RESULTSThree different types of inhalational anaesthetics were usedsevoflurane, 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