CASPER CHILD ADVANCED SAFETY PROJECT FOR EUROPEAN ROADS COVER Workshop - 13th March 2012 Berlin, Germany
Content Agenda Context Biomechanical aspects Analysis - per type of CRS - per impact type Influence - misuse - positioning Conclusions
Context How are abdominal, injuries rated? What does it mean? CASPER Abbreviated Injury Scale Version 1998 AIS 1 (minor) AIS 2 (moderate) AIS 3 (serious) Abdomen Skin and muscle abrasion and light wounds Skin deep wounds or internal organ contusion abdominal wound with blood loss >20%, vessel tears, internal organ contusion (important) or wound AIS 4 (severe) Vessels rupture, internal organ large wound / perforation / rupture AIS 5 (critical) AIS 6 (maximal) Internal organ complete section / rupture Only one injury in abdominal section: hepatic avulsion The time before the arrival of a medical team in case of abdominal injuries, is an important factor regarding the outcome of the injuries.
CHILD and CASPER accident database DUE TO SELECTION CRITERIA BASED ON ACCIDENT SEVERITY THE DATABASE IS NOT REPRESENTATIVE OF REAL WORLD SITUATION BUT ALLOWS SPECIFIC ANALYSIS
How to analyze the database? Context This database contains a lot of information (1288 restrained children at this day) but needs to be held with care: -Because of its non representativity, -What is reported is depending on the analysis focus - example: what is the size of the issue we are talking about? nb of children with abdominal injury / total nb of children 21% n=276 nb of children AIS2+ injuries on abdomen / total nb of children 10% n=133 nb of children with AIS2+ injuries on abdomen with boosters / nb children boosters 14% n=48 nb of children with AIS2+ injuries on abdomen / nb children with AIS2+ with boosters 81% n=48 This presentation deals both with children and injuries but with clear indications of what is shown.
Main injury Mechanisms (1/2) Biomechanical aspects penetration of the restraint system into the abdominal area harness buckle lap part of seatbelt (bad position of seatbelt or rotation of pelvis under the seatbelt)
Main injury Mechanisms (2/2) Biomechanical aspects a scissor effect due to combined movements of the thoracic and pelvic parts of the seatbelt abdominal compression by thoracic part of seatbelt excessive chest deflection and loading of upper abdomen High loading below the rib cage (sliding or bad position of seatbelt)
General overview: children Analysis of CASPER accident db 100% Distribution of abdominal injury severity for children per age 90% 80% 70% 60% 50% n=1288 children abdominal AIS2+ abdominal AIS1 no abdominal injury 40% 30% 20% 10% 0% 0 1 2 3 4 5 6 7 8 9 10 11 12+ age (y)
General overview : injuries Analysis of CASPER accident db Distribution of abdominal injuries per severity AIS1 201 44% AIS2 110 24% AIS3 76 17% AIS4 45 10% AIS5 10 2% AIS6 0 0% AIS9 15 3% 457 100% 241 (53%) Evolution of abdominal injuries across EU projects total nb AIS2+ abdo 241 107 72 62 nb children 1289 645 431 213 19% 17% 17% 29% It s not clear if it is an increase of abdominal injuries or a reduction of the other body segments that creates a bias (selection criteria)
per type of restraint system (1/3) : Analysis of CASPER accident db HARNESS SYSTEMS G1 or combined 0+/1 Body segment AIS2+ AIS3+ Head 29.2% 18.2% Neck 8.6% 7.7% Chest 6.0% 5.7% Abdomen 3.6% 1.5% Upper limbs 5,7% / Lower limbs 8.6% 3.3% n=336 children Figures indicate the ratio between the nb of children sustaining at least one injury of AISx level divided by the number of children using the same type of restraint system
per type of restraint system (2/3) : Analysis of CASPER accident db BOOSTERS (boost.seats + boost.cushions) Body segment AIS2+ AIS3+ Head 24.4% 13.9% Neck 6.0% 3.1% Chest 11.1% 10.5% Abdomen Upper extremities 13.6% 8.0% 12,5% 0.9% Lower extremities 11.9% 5.4% n=355 children Figures indicate the ratio between the nb of children sustaining at least one injury of AISx level divided by the number of children using the same type of restraint system
per type of restraint system (3/3) : Analysis of CASPER accident db (03/2012) SEATBELT Body segment AIS2+ AIS3+ Head 24.2% 8.8% Neck 2.6% 2.0% Chest 11.6% 8.6% Abdomen 14.9% 10.5% Upper extremities 13.2% 1.3% Lower extremities 13.8% 5.5% n=455 children Figures indicate the ratio between the nb of children sustaining at least one injury of AISx level divided by the number of children using the same type of restraint system
Analysis of CASPER accident db (03/2012) Ratio injury / type of restraint system Synthesis per type of restraint systems seatbelt booster harness shield children AIS2+ on abdo 68 48 12 4 injuries AIS2+ abdo 127 89 20 4 total children using system 455 346 333 31 ratio injury/child 1,87 1,85 1,67 1,00 children AIS2+ abdo / nb children using system 15% 14% 4% 13% injuries AIS2+ abdo / nb children using system 28% 26% 6% 13% Caution with sample size
Injury severity and repartition Analysis of CASPER accident db (03/2012) (AIS = Abbreviated Injury Scale) Number of injuries Frontal n=207 AIS 1 (minor) 201 AIS 2 (moderate) 110 AIS 3 (serious) 76 AIS 4 (severe) 45 241 Lateral n=33 AIS 5 (critical) 10 AIS 6 (maximal) 0 Rear impact n=1 Nb of children with AIS2+ on abdomen= 134
Analysis of CASPER accident db (03/2012) FRONTAL repartition of organ injuries (AIS2+) Frontal n=207 Injuries With Child restraint systems (n=93): liver (27%), kidney (13%), spleen (13%) With the seatbelt only (n=114): liver (17%), colon (16%), spleen (13%) Main injury differences (in addition to liver and spleen) with CRS: injuries to kidney, pancreas and stomach, without CRS : injuries to colon, jejunum and mesentery
Analysis of CASPER accident db (03/2012) SIDE IMPACT repartition of organ injuries (AIS2+) Lateral n=34 injuries The sample size only allows to analyze all restraint types together Organs mainly injured: Spleen (37%), liver (37%) Observations with CRS: Injuries to mesentery (harness systems), no kidney injury observed, Spleen injuries only observed on boosters (none in harness systems) Observations with seatbelt: Liver injuries seems to reach a higher rate than injuries on the spleen, Injuries to mesentery observed
CASPER CASPER CASPER accident db AIS3+ organ injuries repartition and comparison with adult data COMPARISON OF ABDOMINAL INJURIES CHILDREN vs ADULTS frontal impact Adults Children (n=83) (not CASPER) 124 448 AIS3+ injuries LIVER 23% SPLEEN 17% KIDNEY 8% PANCREAS 4% JEJUNUM 10% COLON 10% STOMACH 3% MESENTERY 4% DUODENUM 2% BLADDER 1% OTHERS (n= 242) Solid organs 9% 17% 3% 52% 1% 31% 17% Hollow organs 10% 0% 15% 31% 1% 45% 2% 18% 24% Statistically significant Chi2 p=0.0049
Parameters influencying the risk of abdominal injuries Misuse of restraint system (CHILD published AAAM 2007) CASPER abdomen
Parameters influencying the risk of abdominal injuries Stature of children in cars (conducted in CASPER) CASPER Based on few literature available and field data (witnesses and observations), a sled test program has been set and performed in car environment and using the R44 pulse. Results will be presented more in details in the session «applications» but lead to the conclusion that «in many configurations tested, the abdomen is at higher risk» than when seated in a standard position
Conclusions The protection of the abdomen is one of the priorities to improve the situation of restrained children in cars when restrained the seatbelt (with and without CRS) occur often on organs located relatively high in the abdomen (liver and spleen) = likely due to submarining or diagonal belt excessive loading The proportion of injuries to solid organs is higher for children than for adults
Conclusions Misuse is expected to increase the risk of abdominal injury (direct loading to the abdomen, increased risk of submarining, etc) Posture of the child: has an influence on the loads observed in the abdominal area by seatbelt. Extra analysis: G1/2/3 seats with seatbelt, misuse situation in accident data (need check of cases) high back boosters vs low back boosters (need coding), appropriate/inappropriate use (what is the limit to be considered) side impact Left vs right (corrolate with organ injuries)
Acknowledgements The partners wish to acknowledge all the CREST/CHILD and CASPER data collection teams and their sponsors from all the countries involved in this work CASPER UK Loughborough cases, collected during the EC CREST/CHILD projects, include accident data from the United Kingdom Co-operative Crash Injury Study, collected up to 2006. CCIS was managed by TRL Ltd on behalf of the Department for Transport (Transport Technology and Standards Division) who funded the project with Autoliv, Ford Motor Company, Nissan Motor Europe and Toyota Motor Europe. The data were collected by teams from the Birmingham Automotive Safety Centre of the University of Birmingham, the Vehicle Safety Research Centre at Loughborough University, and the Vehicle & Operator Services Agency of the Department for Transport. The views expressed in this work are those of the authors and not necessarily those of the UK CCIS sponsors.
Thank you for your attention! Contact: Philippe LESIRE LABORATOIRE D ACCIDENTOLOGIE ET DE BIOMECANIQUE PSA PEUGEOT-CITROEN / RENAULT 132, rue des suisses F92000 - FRANCE Visit our website: www.casper-project.eu Tel.: +33 (0) 1 76 87 35 60 philippe.lesire@lab-france.com