Topic 1 - Summary
1. Citation:

Chinta, S. (2015) Rapid Administration Technique of Ketamine for Pediatric Forearm Fracture Reduction: A Dose-Finding Study, Annals of Emergency Medicine, Volume 65 (No.6) 640-648

2. Summary/Bottom Lines:

The goal of this study was to determine if lower doses of rapidly infused ketamine can achieve adequate sedation in a pediatric population and if so at what doses. Their primary outcome was to find the ED50 and ED95 of rapidly infused ketamine. Their secondary outcomes were total sedation time, frequency of adverse events, and patient or parent satisfaction.  

The authors studied a cohort of children aged 2-17 in a tertiary care pediatric trauma center in St. Louis. They found an ED 95 of 0.7, 0.7, and 0.8mg/kg for groups aged 2-5, 6-11, and 12-17. For the youngest group, they empirically derived a value of 0.8mg/kg for their ED95. They found the median total sedation had a range of 22.5-25 minutes if participants received one dose of ketamine and 25-45 minutes if multiple doses were used. These times are lower than times found in previous studies which found recovery times of 45-84 minutes when using larger, slower doses.

3. Methods: They used a convenience sample of kids aged 2-17 who required sedation for a forearm reduction in the ED.  A total of 62 were approached and two were excluded due to dosing errors. They used the up-down method of Dixon to determine doses. They began with empiric dose of ketamine for each age group: 1.0, 0.6, and 0.5mg/kg for the 2-5, 6-11, 11-17 age groups respectively.  Within each cohort, the subsequent patient’s ketamine dose then was determined by effectiveness of sedation according previous patient’s ketamine dose. Doses were adjusted by 0.1mg/kg increments. All doses were given by the Principal Investigator of the project, who also determined recovery times, and effectiveness of sedation was determined by 2-3 expert reviewers blinded to dose by video.  Results were analyzed using a logistic regression model to estimate ED 50 and ED 95 and dose response curves where also calculated based on dose. A Profile Penalized Likelihood Approach  was used to calculate confidence intervals of doses and Kappa coefficients were used to assess inter-rater reliability. 
4. Limits:

Patients with injuries other than forearm reductions may require different doses for efficacy. The effectiveness of sedation, while blinded to dose, did not use a validated standardized tool for assessment. Additionally, the sample size was not powered to assess adverse events such as apnea or respiratory depression. Finally, recording bias may be present as the PI determined the recovery times from sedation. 

5. Additional Info:

Although this study was not powered to assess the safety of ketamine using smaller doses that are rapidly infused, many studies have shown that ketamine is a relatively safe drug that is unlikely to cause respiratory depression. Additionally, most providers infuse ketamine at rates faster than their comparison 30-60 second infusion times. This study demonstrated that smaller doses infused more rapidly can achieve effective sedation and can be considered in practice. 

6. Presenter:    Ronald Nelson, M.D.


Topic 2 - Summary
1. Citation:  Holmes (2013) Identifying Children at Very Low Risk of Clinically Important Blunt Abdominal Injuries, Annals of Emergency Medicine Volume 62 (No.2) 107-116
2. Summary/Bottom Lines:

This is a prospective observational cohort study performed in 20 emergency departments in the PECARN group of hospitals that attempts to answer the question: in children with blunt torso trauma evaluated in the Emergency Department, can we derive a prediction rule based on certain historical and physical exam findings that will allow treating physicians to identify children at very low risk for intra-abdominal injuries needing acute intervention and in which CT can be avoided?

3. Methods:

Of the 12044 patients enrolled, 761 (6.3%) had intra-abdominal injuries and of that, 203 (1.7%) had intra-abdominal injuries that underwent acute intervention. Out of the 203 patients that had intra-abdominal injuries, 197 had at least 1 predictor present while 7 did not, leading to a 97% sensitivity

4. Limits:

A prediction rule consisting of 7 patient history and physical exam findings (lack of: evidence of abdominal wall trauma/seat belt sign, GCS score < 14, abdominal tenderness, evidence of thoracic wall trauma, complaints of abdominal pain, decreased breath sounds, and vomiting), and without laboratory or U.S. information, identifies children with blunt torso trauma who are at very low risk for intra-abdominal injury undergoing acute intervention.

5. Additional Info:
Although external validation is still required, using this rule appropriately (i.e. to rule out patients who do not have intra-abdominal injuries needing surgical intervention) can lead to a reduction in abdominal CT scans for children. The use of laboratory and US information in addition to this rule out criteria can further reduce the amount of CT scans needed in this population.
6. Presenter:  Ryan Ruiz, M.D.