Rogerson C, Abulebda K, Hobson M Hospital Pediatrics. 2017 Sept 7(9): 542-546.
This study examined the effect of BMI, from underweight to obesity, on dosing of propofol and adverse events for children with cancer who were deeply sedated for painful procedures.
Retrospectively they studied pediatric oncology patients over a five-year span (2010-2015). The patients received an initial dose of ketamine prior to propofol boluses (1-2mg/kg at start of sedation and 0.5-1mg/kg for subsequent doses as needed). Procedures included lumbar punctures, bone marrow aspirates or both. They calculated BMI and monitored adverse events (hypoxemia, apnea, bradycardia and hypotension).
The 1,976 cases in the study were not significantly different in terms of age with consideration of weight and procedure. Overweight (BMI > 85th percentile) and obese (BMI > 95th percentile) children achieved deep sedation with significantly lower doses of propofol per kg of body weight as compared to those children of normal body weight. Underweight children required similar propofol dosing as normal weight children. Underweight children experienced more adverse events than normal weight children, yet there was no significant difference between the number of adverse events among the four weight categories of the patients (underweight, normal weight, overweight and obese).
Children can still be successfully sedated at lower doses of propofol to minimize adverse events. Underweight children may be at risk for complications during sedation.
We have all seen firsthand the rise in obesity in the children we sedate yet we may not often consider the risk of complications with the underweight population. The authors of the above study remind us of the impact of BMI across the spectrum. They confirmed the impact of underweight and its impact on sedation (respiratory muscle weakness from malnourishment, less adipose tissue for propofol to circulate). Although the authors did acknowledge that the propofol dosing was decided by the individual physicians, perhaps we need to consider smaller dosing with the underweight population.
On a larger scale, Scherrer et al similarly explored adverse events and interventions with the obese population in a larger retrospective analysis provided by data from the Pediatric Sedation Research Consortium. This manuscript entitled: The impact of obesity on pediatric procedural sedation-related outcomes: Results from the Pediatric Sedation Research Consortium was published in Pediatric Anesthesia in 2014 (Volume 25, pages 689-697). Of the 28,792 records analyzed, they noted that 17.9% of these patients were obese and experienced more adverse events (airway obstruction, oxygen desaturation, secretions requiring treatment and laryngospasm). They also found that a higher percentage of these obese patients had an inability to complete procedures and prolonged recovery.
Both of these studies remind us of the importance of BMI as we prescreen and sedate our patients. Further studies are warranted, especially regarding the dosing of sedation medications and consideration of total body weight versus ideal body weight. Although the sedation providers should be prepared to manage adverse events, our goal is to minimize their occurrence and administer the minimal amount of medication to achieve the desired level of sedation in the safest of circumstances.