The effect of obesity on the ED(95) of propofol for loss of consciousness in children and adolescents.

Abstract

INTRODUCTION:

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.

DISCUSSION:

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: Olutoyin A Olutoye, Xiaoying Yu, Kalyani Govindan, Imelda M Tjia, Deborah L East, Renee Spearman, Priscilla J Garcia, Crystal Coulter-Nava, Jennifer Needham, Stephanie Abrams, Claudia A Kozinetz, Dean B Andropoulos, Mehernoor F Watcha
• Journal: Anesthesia and analgesia (Anesth Analg) Vol. 115 Issue 1 Pg. 147-53 (Jul 2012) ISSN: 1526-7598 [Electronic] United States
• PMID: 22575569 (Publication Type: Journal Article, Research Support, Non-U.S. Gov't)

Chemical References

• Anesthetics, Intravenous
• Propofol

Topics

• Adolescent
• Age Factors
• Anesthetics, Intravenous (administration & dosage)
• Body Mass Index
• Child
• Child, Preschool
• Consciousness (drug effects)
• Drug Dosage Calculations
• Eyelids (drug effects)
• Humans
• Obesity (complications, diagnosis, psychology)
• Propofol (administration & dosage)
• Reflex (drug effects)
• Regression Analysis
• Texas
• Time Factors