Childhood obesity: a growing problem for the pediatric anesthesiologist

Use of Fentanyl in Adolescents with Clinically Severe Obesity Undergoing Bariatric Surgery: A Pilot Study

BACKGROUND

The number of obese pediatric patients requiring anesthesia is rapidly increasing. Although fentanyl is a commonly used narcotic during surgery, there are no pharmacokinetic (PK) data available for optimal dosing of fentanyl in adolescents with clinically severe obesity.

MATERIALS AND METHODS

An institutional review board-approved exploratory pilot study was conducted in six adolescents aged 14-19 years undergoing bariatric surgery. Mean total body weight (TBW) and mean BMI were 137.4 ± 14.3 kg and 49.6 ± 6.4 kg/m² (99.5th BMI percentile), respectively. Fentanyl was administered intravenously for intraoperative analgesia based on ideal body weight per standard of care. PK blood samples were drawn over a 24-h post-dose period. Fentanyl PK parameters were calculated by non-compartmental analysis.

RESULTS

Mean fentanyl AUC_0-∞ was 1.5 ± 0.5 h·ng/mL. Systemic clearance of fentanyl was 1522 ± 310 mL/min and 11.2 ± 2.6 mL/min·kg TBW. Volume of distribution was 635 ± 282 L and 4.7 ± 2.1 L/kg TBW. While absolute clearance was increased, absolute volume of distribution was comparable to previously established adult values.

CONCLUSIONS

These results suggest that fentanyl clearance is enhanced in adolescents with clinically severe obesity while volume of distribution is comparable to previously published studies.

STUDY REGISTRATION

NCT01955993 (clinicaltrials.gov).

Incidence of perioperative adverse events in obese children undergoing elective general surgery

BACKGROUND

A worldwide increase in the prevalence of obesity has been observed in both developed and developing countries. Few studies have addressed the anaesthetic or perioperative implications of childhood obesity.

METHODS

Children aged 2-16 yr undergoing general surgery were classified using age- and sex-adjusted BMI. Patient characteristic, co-morbidity, and perioperative data were collected to ascertain the risks associated with overweight and obese children.

RESULTS

We enrolled 1465 subjects in our study, of which 154 (10.5%) were classified as obese and a further 223 (15.2%) as overweight. After adjusting for age, we identified increased rates of arterial haemoglobin desaturation, difficult mask ventilation, airway obstruction, and bronchospasm in obese children. The relative risk (RR) of adverse respiratory events was higher among obese subjects than non-obese subjects and higher in younger age groups. Controlling for age, adjusted-RR (confidence interval) was 1.49 (1.2-1.86). There was a significant association between obesity and asthma with a higher odds ratio (OR) in younger age groups controlling for age: adjusted-OR=1.8 (1.15-2.82). A significant association was detected between obesity and sleep apnoea controlling for age: adjusted-OR=4.03 (2.37-6.8).

CONCLUSIONS

These results suggest an increased incidence of perioperative adverse respiratory events in obese children, especially at younger ages.