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Literature Reviews

Do children with high 
body mass indices have a higher incidence of emesis when undergoing ketamine sedation?

Etomidate for short pediatric procedures in the emergency department

Intranasal fentanyl and
high-concentration inhaled nitrous oxide for procedural sedation: A prospective observational pilot study of adverse events and depth of sedation


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Literature Review

Do children with high body mass 
indices have a higher incidence of emesis when undergoing ketamine sedation?

Reviewed by Daniel Tsze, MD and Joseph Cravero, MD

Kinder KL, Lehman-Huskamp KL, Gerard JM. Pediatr Emerg Care. 2012 Nov;28(11):1203-5.

Ketamine is the most commonly used agent in children for facilitating painful procedures in the emergency department (ED)1. A large meta-analysis of ketamine sedations has shown that the overall incidence of emesis is 8.4%, with the most important predictors of emesis being unusually high intravenous doses, the intramuscular route, and increasing age2. This is the first study to look specifically at the incidence of nausea/vomiting during or after ketamine sedation with respect to patient body habitus and it has significant implications for care.

This is a retrospective study in which the authors identified 141 children between the ages of 2 and 18 years with an ASA classification of I or II, who underwent IV procedural sedation with ketamine, with or without midazolam, for uncomplicated fracture reduction.  Age, sex, sedation time, and doses of medications administered were extracted.  The actual height for each patient was not available, so an estimated height based on the fiftieth percentile for age and sex was used to calculate the body mass index (BMI).  The incidence of emesis and nausea was evaluated using administration of ondansetron as a proxy for these issues.

Seventy-eight percent of patients had a normal BMI (< 25), and 22% had a high BMI (≥25).  The normal- and high-BMI groups differed in that the former group received a higher dose of midazolam on a per-kilogram basis.  Five patients in each group received ondansetron (4.5% and 16.1%, respectively), which was a statistically significant difference between groups (p=0.04).


This study is limited primarily by two things: the unavailability of each patient’s actual height for calculation of BMI scores, and the absence of reliable documentation of emesis and nausea.  The authors attempt to compensate for these limitations by using a more conservative definition of “overweight”. They note that the incidence of obesity in this study, using this method of BMI estimation, is congruous with the reputable reports of national prevalence3.  They also comment that the overall incidence of ondansetron administration in their study (7.1%) is similar to the incidence of emesis reported in a large meta-analysis (8.4%), which would support the use of ondansetron administration as suitable proxy for emesis2

Despite these limitations, this study raises an important concern with regards to the incidence of adverse events during procedural sedation in the ED in overweight and obese children.  Obesity is a serious and growing problem in the pediatric population, and can pose added risk for practitioners providing procedural sedation.  Previous studies have shown that overweight and obese children are at greater risk of adverse events when undergoing anesthesia (e.g. oxygen desaturation, difficult mask ventilation, airway obstruction, and bronchospasm), which would suggest that this same population may also be at greater risk of adverse events when undergoing procedural sedation4-7.  Although the findings of this study are not conclusive, they do suggest that this population may have a higher incidence of emesis during procedural sedation with IV ketamine, and that this population may benefit from emesis prophylaxis with ondansetron.  While this study is not conclusive as to whether or not there is a greater incidence of adverse events in this population, it does serve to bring attention to the serious concern that overweight and obese children are a high risk population when it comes to providing procedural sedation outside of the operating room. These patients require a higher level of care and vigilance than the general population, and there is a significant need to dedicate further prospective study with this subset of the population as the focus.


  1. Bhargava R et al.  Procedural pain management patterns in academic pediatric emergency departments.  Acad Emerg Med. 2007;14:479-482.
  2. Green SM et al. Predictors of emesis and recovery agitation with emergency department ketamine sedation: an individual-patient data meta-analysis of 8,282 children. Ann Emerg Med. 2009;54:171-180.
  3. National Center for Chronic Disease Prevention and Health Promotion.  Health Topics: Childhood Obesity.  Available at: Accessed June 18, 2011.
  4. Tait AR et al. Incidence and risk factors for perioperative adverse respiratory events in children who are obese.  Anesthesiology.  2008;108:375-380.
  5. El-Metainy S et al. Incidence of perioperative adverse events in obese children undergoing elective general surgery. Br J Anesth. 2010;106:359-363.
  6. Setzer N et al. Childhood obesity and anesthetic morbidity.  Pediatr Anesth. 2006;17:321-326.
  7. Naflu O et al. Childhood body mass index and perioperative complications.  Pediatr Anesth. 2007;17:426-430.

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