Defining Severity, Time-Sensitivity and Predictability of Common Pediatric Injuries Joel Stitzel, PhD – PI Andrea Doud MD, Ashley Weaver PhD, Jennifer Talton MS, Ryan Barnard MS, Samantha Schoell BS, Wayne Meredith MD, Shayn Martin MD, John Petty MD Wake Forest University School of Medicine, Virginia Tech – Wake Forest University Center for Injury Biomechanics Wake Forest Baptist Medical Center
Disclosures • Funded by the Center for Child Injury Prevention Studies (CChIPS) - Multi-university Industry/University Cooperative Research Center (I/UCRC) • Supported by Childress Institute for Pediatric Trauma Wake Forest Baptist Medical Center
Injury Severity Measures Currently, the most widely used severity metrics are based upon the Abbreviated Injury Scale (AIS) AIS Description X X X X X X . X 1 Minor 2 Moderate Severity metric 3 Serious Anatomic 4 Severe classification 5 Critical 6 Maximum AIS Severity metrics: • Not created for use in children • Based on consensus opinion • May not capture all aspects of injury that determine need for treatment at a Trauma Center (TC) Wake Forest Baptist Medical Center
Injury Severity Scoring Alternative Target injuries: Injuries likely to need treatment at a TC given their severity, time sensitivity and predictability Project Goal : Determine the severity, time-sensitivity & Time- Predictability Sensitivity predictability of most common pediatric injuries within 4 age subsets Severity 0-4 yr 5-9 yr 10-14 yr 15-18 yr Wake Forest Baptist Medical Center
Severity NTDB 2002-2012 utilized to determine mortality risk ratios (MRRs) for the most common pediatric injuries Largest aggregation of trauma registry data # Dying after injury = MRR Total # with injury 0 1 Fewer Patients More Patients Dying with Injury Dying with Injury (Less Severe) (More Severe)
Severity The most common pediatric injuries result in differing mortality risks between age groups. Median MRR by Age Group p<0.001 p=0.04 0.1 p=0.03 p<0.0001 0.08 Median MRR 0.07 0.06 0.05 0.04 0.04 0.03 0.02 0 0-4yo 5-9yo 10-14yo 15-18yo n=112 injuries n=194 injuries n=156 injuries n=125 injuries
Time Sensitivity Survey of Expert Opinion Experts included pediatric & orthopaedic surgeons and emergency medicine physicians For each injury, experts asked: 1. Does this injury require treatment at a TC? 2. How urgently does the injury require treatment from a scale of 1 (not urgently) to 5 (urgently)?
Time Sensitivity Screen shot of Electronic Survey Injury Description: Kidney Laceration, Grade 2
Time Sensitivity Scores Injuries in the youngest children are more time sensitive than injuries in the oldest children. Median Time Sensitivity Scores By Age Group Median Time Sensitivity Scores by Age Group p<0.0001 p=0.0001 p=0.018 1 p=0.05 0.9 0.8 Median TS Scores 0.7 0.6 0.5 0.4 0.3 0.2 0.1 0 0-4 year 5-9 year 10-14 year 15-18 year n=112 injuries n=194 injuries n=125 injuries n=156 injuries Wake Forest Baptist Medical Center
Predictability Predictability Score Consensus-derived “Occult Score” (survey) Data-Derived “Transfer Score” (NIS) Wake Forest Baptist Medical Center
Consensus-Derived Occult Score Experts surveyed For each question, participants asked to assess the likelihood that the injury might be missed on initial assessment
Data-Derived Transfer Score National Inpatient Sample (NIS) - Supported by HCUP - Tracks national trends in health care use # with Injury transferred to TC Transfer = Score Total # with Injury 0 1 More Patients Fewer Patients Requiring Requiring Transfer = More Transfer = Less Occult Occult Wake Forest Baptist Medical Center
Predictability Scores Injuries in the youngest children less predictable (more occult & more highly transferred) than injuries in older children. Median Predictability Scores By Age Group p=0.001 p<0.0001 p=0.04 p<0.0001 0.4 Median Predictability Score p=0.03 0.35 0.3 0.25 0.2 0.15 0.1 0.05 0 0-4 years 5-9 years 10-14 years 15-18 years n=112 injuries n=194 injuries n=125 injuries n=156 injuries Wake Forest Baptist Medical Center
“ AIS Glasses” Wake Forest Baptist Medical Center
AIS Performance 0-4 year olds Cerebrum Subarachnoid Open Tibia Fracture Hemorrhage (AIS 3) (AIS 3) Severity* 0.69 (High) 0.00 (Low) Time Sensitivity: 0.95 (High) 0.86 (Moderate) Predictability: 0.71 (High) 0.07 (Low) Target Injury Score: 2.35 0.93 *Severity Score = Log-normalized Co-Injury adjusted Mortality Risk Ratio (MRR MAIS ) Wake Forest Baptist Medical Center
Conclusions • Current AIS-based severity metrics not created for children & may not capture all aspects of injury • Evaluation of Severity , Time Time- Predictability Sensitivity and Predictability provide Sensitivity more robust assessment of injury Severity • Future applications will involve integration of Target Injury Scores into an Advanced Automatic Crash Notification Algorithm Wake Forest Baptist Medical Center
Thank you! Questions?
BACK-UP SLIDES
Determining the Most Frequent Injuries 2000-2011 Excluded 2009-2011 with MY > 10 yrs (injury data missing) Inclusion Criteria - Age < 19yo - AIS 2+ Injuries 95%: 195 100%: 551 Unique Unique Injuries 60000 120% Weighted Injury Count Injuries Cumulative Percent 50000 100% 40000 80% 30000 60% 20000 40% 10000 20% 0 0% 0 50 100 150 200 250 200 350 400 450 500 550 1 51 101 151 201 251 301 351 401 451 501 551 NASS 2000-2011 AIS 2+ Injury Ranking
Mortality Risk Ratios (MRR) 1 st component of severity score = MRRs Year 1 calculated MRR and MRR MAIS using 2002-2006 data Year 2 incorporated NTDB 2007-2011 as well Deaths 20 MRR = = = 0.20 Total Injured 100 MAIS Deaths w/ MAIS = Injury’s AIS = Adjusted MRR Total Injured w/ MAIS = Injury’s AIS (MRR MAIS ) Excludes patients w/ AIS 2 Injury: 60 of 100 Injured w/ MAIS =2 higher AIS co-injuries 5 Deaths (MAIS = 2) = = 0.12 60 Injured (MAIS =2)
Distributions of MRR and MRR MAIS by Age Group 0-4 years: MRR MRR MAIS • MRR and MRR MAIS analyses using increased sample sizes MRR 5-9 years: MRR MAIS • Distributions of data remain right-skewed 10-14 years: MRR MRR MAIS 15-18 years: MRR MRR MAIS Wake Forest Baptist Medical Center
MRR Severity vs AIS Severity • There is an overall positive correlation between AIS Severity and MRR/MRR MAIS . • Within each AIS Severity, there, is large variation in MRR & MRR MAIS • There are some lower severity AIS scores that have higher MRRs & MRR MAIS than higher severity AIS Scores. Plots for 0-18 years shown below. Plots for other pediatric subsets appear similar. MRR MAIS by AIS Severity, 0-18 years MRR by AIS Severity, 0-18 years 1.2 1.2 y = 0.1053x - 0.2446 y = 0.1008x - 0.1844 R² = 0.5517 1 R² = 0.481 1 y = 0.0593x 2 - 0.3058x + 0.3803 y = 0.0471x 2 - 0.2258x + 0.312 0.8 0.8 R² = 0.7999 R² = 0.63 MRR MRR MAIS 0.6 0.6 0.4 0.4 0.2 0.2 0 0 2 3 4 5 6 2 3 4 5 6 -0.2 AIS Severity AIS Severity
Comparing Mortality between Adults & Children MRR MAIS for an injury in each pediatric group of note is plotted against the MRR MAIS of that injury in the >/= 19 year (adult) group. Injuries are categorized by body region as noted in the legend. Injuries appearing below the equivalency line demonstrated a greater MRR MAIS for adults than for the stratified pediatric age group of note 1 1 0.1 0.1 MRR MAIS 0-4 Years MRR MAIS 5-9 Years 0.01 0.01 0.001 0.001 0.000 0.000 0.0001 0.0001 0.0001 0.001 0.01 0.1 1 0.0001 0.001 0.01 0.1 1 MRR MAIS >/=19 Years MRR MAIS >/=19 Years Equivalency Line Wake Forest Baptist Medical Center
Comparing Mortality between Adults & Children MRR MAIS for an injury in each pediatric group of note is plotted against the MRR MAIS of that injury in the >/= 19 year (adult) group. Injuries are categorized by body region as noted in the legend. Injuries appearing below the equivalency line demonstrated a greater MRR MAIS for adults than for the stratified pediatric age group of note 1 1 0.1 0.1 MRR MAIS 15-18 Years MRR MAIS 10-14 Years 0.01 0.01 0.001 0.001 0.000 0.0001 0.000 0.0001 0.001 0.01 0.1 1 0.0001 0.0001 0.001 0.01 0.1 1 MRR MAIS >/= 19 Years MRR MAIS >/= 19 Years Equivalency Line Wake Forest Baptist Medical Center
Disability Risk Ratios Mimicking what was done in Potoka et al, we chose to “dichotomize” FIM Scores If any of these were 1 or 2 then patient labeled as “Disabled” (obviously we would explain there are diff FIM FEED levels of disability but all of these patients had some FIM LOCOMOT level of more than mild disability at discharge) FIM EXPRESS If all are 3 or 4 then patient is “Not disabled” For each AIS code, we then calculated the following: # Disabled after injury DRR = Total # with injury (Disability Risk Ratio) Wake Forest Baptist Medical Center
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