title: The effect of obesity on the ED(95) of propofol for loss of consciousness in children and adolescents.
abstract: BACKGROUND
  Anesthesiologists face a dilemma in determining appropriate dosing of anesthetic drugs in obese children. In this study we determined the dose of propofol that caused loss of consciousness in 95% (ED(95)) of obese and nonobese children as determined by loss of eye lash reflex.
  
  
  METHODS
  Forty obese (body mass index [BMI] > 95th percentile for age and gender) and 40 normal weight (BMI 25th to 84th percentile) healthy ASA 1 to 2 children ages 3 to 17 years presenting for surgical procedures were studied using a biased coin design. The primary endpoint was loss of lash reflex at 20 seconds after propofol administration. The first patient in each group received 1.0 mg/kg of IV propofol, and subsequent patients received predetermined propofol doses based on the lash reflex response in the previous patient. If the lash reflex was present, the next patient received a dose increment of 0.25 mg/kg. If the lash reflex was absent, the next patient was randomized to receive either the same dose (95% probability) or a dose decrement of 0.25 mg/kg (5% probability). The ED(95) and 95% confidence intervals (CI) were calculated using isotonic regression and bootstrapping methods respectively.
  
  
  RESULTS
  The ED(95) of propofol for loss of lash reflex was significantly lower in obese pediatric patients (2.0 mg/kg, approximate 95% CI, 1.8 to 2.2 mg/kg) in comparison with nonobese patients (3.2 mg/kg, approximate 95% CI, 2.7 to 3.2 mg/kg), P ≤ 0.05.
  
  
  CONCLUSIONS
  A simple approach to deciding what dose of propofol should be used for induction of anesthesia in children ages 3 to 17 years is to first establish the child's BMI on readily available gender-specific charts. Obese children (BMI >95th percentile for age and gender) require a lower weight-based dose of propofol for induction of anesthesia, than do normal-weight children.
authors.affiliation: Departments of Anesthesiology and Pediatrics, 6621 Fannin Street, Suite A-300, Texas Children's Hospital, MC 2-1495, Houston TX 77030, USA. oao@bcm.edu
authors.forename: Olutoyin A
authors.initials: OA
authors.lastname: Olutoye
authors.forename: Xiaoying
authors.initials: X
authors.lastname: Yu
authors.forename: Kalyani
authors.initials: K
authors.lastname: Govindan
authors.forename: Imelda M
authors.initials: IM
authors.lastname: Tjia
authors.forename: Deborah L
authors.initials: DL
authors.lastname: East
authors.forename: Renee
authors.initials: R
authors.lastname: Spearman
authors.forename: Priscilla J
authors.initials: PJ
authors.lastname: Garcia
authors.forename: Crystal
authors.initials: C
authors.lastname: Coulter-Nava
authors.forename: Jennifer
authors.initials: J
authors.lastname: Needham
authors.forename: Stephanie
authors.initials: S
authors.lastname: Abrams
authors.forename: Claudia A
authors.initials: CA
authors.lastname: Kozinetz
authors.forename: Dean B
authors.initials: DB
authors.lastname: Andropoulos
authors.forename: Mehernoor F
authors.initials: MF
authors.lastname: Watcha
mesh_terms: D000293:Adolescent; D000367:Age Factors; D018686:Anesthetics, Intravenous / Q000008:administration & dosage*; D015992:Body Mass Index; D002648:Child; D002675:Child, Preschool; D003243:Consciousness / Q000187:drug effects*; D054796:Drug Dosage Calculations; D005143:Eyelids / Q000187:drug effects; D006801:Humans; D009765:Obesity / Q000150:complications* / Q000175:diagnosis / Q000523:psychology; D015742:Propofol / Q000008:administration & dosage*; D012018:Reflex / Q000187:drug effects; D012044:Regression Analysis; D013781:Texas; D013997:Time Factors
chemical_list: D018686:Anesthetics, Intravenous; D015742:Propofol