title: Impact of depth of propofol anaesthesia on functional residual capacity and ventilation distribution in healthy preschool children.
abstract: BACKGROUND
  Propofol is commonly used in children undergoing diagnostic interventions under anaesthesia or deep sedation. Because hypoxaemia is the most common cause of critical deterioration during anaesthesia and sedation, improved understanding of the effects of anaesthetics on pulmonary function is essential. The aim of this study was to determine the effect of different levels of propofol anaesthesia on functional residual capacity (FRC) and ventilation distribution.
  
  
  METHODS
  In 20 children without cardiopulmonary disease mean age (SD) 49.75 (13.3) months and mean weight (SD) 17.5 (3.9) kg, anaesthesia was induced by a bolus of i.v. propofol 2 mg kg(-1) followed by an infusion of propofol 120 microg kg(-1) min(-1) (level I). Then, a bolus of propofol 1 mg kg(-1) was given followed by a propofol infusion at 240 microg kg(-1) min(-1) (level II). FRC and lung clearance index (LCI) were calculated at each level of anaesthesia using multibreath analysis.
  
  
  RESULTS
  The FRC mean (SD) decreased from 20.7 (3.3) ml kg(-1) at anaesthesia level I to 17.7 (3.9) ml kg(-1) at level II (P < 0.0001). At the same time, mean (SD) LCI increased from 10.4 (1.1) to 11.9 (2.2) (P = 0.0038), whereas bispectral index score values decreased from mean (SD) 57.5 (7.2) to 35.5 (5.9) (P < 0.0001).
  
  
  CONCLUSIONS
  Propofol elicited a deeper level of anaesthesia that led to a significant decrease of the FRC whereas at the same time the LCI, an index for ventilation distribution, increased indicating an increased vulnerability to hypoxaemia.
authors.affiliation: Division of Anaesthesia, University of Basel Children's Hospital, Basel, Switzerland. bvonungern@uhbs.ch
authors.forename: B S
authors.initials: BS
authors.lastname: von Ungern-Sternberg
authors.forename: F J
authors.initials: FJ
authors.lastname: Frei
authors.forename: J
authors.initials: J
authors.lastname: Hammer
authors.forename: A
authors.initials: A
authors.lastname: Schibler
authors.forename: R
authors.initials: R
authors.lastname: Doerig
authors.forename: T O
authors.initials: TO
authors.lastname: Erb
mesh_terms: D018686:Anesthetics, Intravenous / Q000008:administration & dosage / Q000494:pharmacology*; D002675:Child, Preschool; D004305:Dose-Response Relationship, Drug; D004569:Electroencephalography; D005260:Female; D005652:Functional Residual Capacity / Q000187:drug effects*; D006801:Humans; D008297:Male; D015742:Propofol / Q000008:administration & dosage / Q000494:pharmacology*; D015656:Respiratory Mechanics / Q000187:drug effects; D013990:Tidal Volume / Q000187:drug effects
chemical_list: D018686:Anesthetics, Intravenous; D015742:Propofol