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The Abdominal Pressure Twin Sensors (APTS) for Q3 and Q6 dummies are composed of soft polyurethane bladders filled with fluid and equipped with pressure sensors. Implanted within the abdominal insert of child dummies, they can be used to detect abdominal loading due to the belt during frontal collisions. In the present study - which is part of the EC funded CASPER project - two versions of APTS (V1 and V2) were evaluated in abdominal belt compression tests, torso flexion test (V1 only) and two series of sled tests with degraded restraint conditions. The results suggest that the two versions have similar responses, and that the pressure sensitivity to torso flexion is limited. The APTS ability to detect abdominal loading in sled tests was also confirmed, with peak pressures typically below 1 bar when the belt loaded only the pelvis and the thorax (appropriate restraint) and values above that level when the abdomen was loaded directly (inappropriate restraint). Then, accident reconstructions performed as part of CASPER and previous EC funded projects were reanalyzed. Selected data from 19 dummies (12 Q6 and 7 Q3) were used to plot injury risk curves. Maximum pressure, maximum pressure rate and their product were all found to be injury predictors. Maximum pressure levels for a 50% risk of AIS3+ were consistent with the levels separating appropriate and inappropriate restraint in the sled tests (e.g. 50% risk of AIS3+ at 1.09 bar for pressure filtered CFC180). Further work is needed to refine the scaling techniques between ages and confirm the risk curves.

Background The purpose of this study is to quantify the in vivo mechanical response of the child trunk under loading during physiotherapy treatments. Methods Twenty-six children aged 45 days to 7 years (14 girls and 12 boys) took part in this study. The forces applied by the physiotherapist were recorded using a force-plate embedded in the manipulation table supporting the child. Two synchronized cameras filmed the scene in a calibrated environment. The displacement of reflective targets glued on the physiotherapist's hands was calculated using an automatic tracking procedure and the 3D reconstruction “Direct Linear Transformation” algorithm. The progression of physical parameters was evaluated according to the age of the child. They included force, displacement, normalized displacement, loading speed, displacement and normalized displacement at the maximum force, force at the maximum displacement, viscous criterion and effective stiffness. Findings For all patients, the mean maximum displacement and load were 22 mm (SD 9 mm) and 240 N (SD 46 N) respectively. The force–displacement curves had shown the complexity of the in vivo behavior: four phases have been distinguished with cycles in respect with the respiratory phases. The increase in force always occurred before the increase in displacement. Interpretation This study helps to understand the in vivo behavior of the child trunk subjected to repetitive non-injurious mechanical loading. Further analysis in other populations and with different therapeutic maneuvers would refine the results.

34e Congrès de la Société de Biomécanique, TOULON, FRANCE, 31-/08/2009 - 02/09/2009; The aim of our study is to obtain realistic values of child thoracic and abdominal compliance. The thoracic and abdominal compliance represents the capacity of deformation under spontaneous or mechanical ventilation. The Pediatric Medical Center (CMP) in la MaisonneŽe receives children with neuromuscular pathologies ventilated with invasive or non-invasive methods. The respiratory function of these children naturally deteriorates over time, and breathing development programs, that may or may not be associated with thoracic pressure, are put in place to minimise this mostly restrictive aggravation. Intermittent positive pressure breathing (IPPB) is a technique used to provide short-term or intermittent mechanical ventilation for the purpose of augmenting lung expansion, delivering aerosol medication, or assisting ventilation. The 'traditional' use of IPPB lacks precise evaluation, especially of thoracic mobility. Poster : hal-01738729

34e Congrès de la Société de Biomécanique, TOULON, FRANCE, 31-/08/2009 - 02/09/2009; Le centre Médical Pédiatrique de la Maisonnée accueille des enfants présentant une pathologie neuromusculaire ventilés sur trachéotomie ou par les voies naturelles. La fonction respiratoire de ces enfants se détériore naturellement au fil des années et des programmes de développement du « souffle », associé ou non à des pressions thoraciques sont mis en place pour minimiser cette aggravation essentiellement restrictive. L'objectif de ce travail est d'évaluer ces programmes en quantifiant en particulier la mobilité thoracique qu'ils génèrent

22nd Congress of the International Society of Biomechanics, CAPE TOWN, AFRIQUE DU SUD, 05-/07/2009 - 09/07/2009; The aim of this study was to determine the loading level of child trunk during physiotherapy treatments

12th International Conference on Home Mechanical Ventilation, BARCELONE, ESPAGNE, 27-/03/2009 - 28/03/2009; The CMP (Pediatric Medical Center) in la Maisonnée receives children with neuromuscular pathologies ventilated with invasive or non-invasive methods. The respiratory function of these children naturally deteriorates over time, and breathing development programs, that may or may not be associated with thoracic pressure, are put in place to minimize this mostly restrictive aggravation. The traditional use of IPPB lacks precise evaluation, especially of thoracic mobility. In collaboration with INRETS (the French National Institute for Transport and Safety Research), a measurement table, used in association with two digital video cameras, has been designed to record both pressure and thoracic movements. Seven children were recorded using two or three ventilation modes : - via spontaneous ventilation if the child is breathing unassisted - via mechanical ventilation - via IPPB. The targets were placed on the sternum, the abdomen, the xiphoid process and the ribs. All these children suffer from respiratory failure of neuromuscular origin. Their average age is seven (14 months to 16 years old). Initial results highlight a much higher thoracic compliance under IPPB in all cases. IPPB versus spontaneous ventilation : + 64,8% (the highest result is registred on costal targets +65,4%) IPPB versus barometric or volumetric ventilation : +54,1% An abdominal contention increase thoracic movement but decrease abdominal movement Conclusion This new tool enables the precise measurement of children's thoracic compliance, thereby making it easier to appreciate whether there is a need to implement hyperinsufflation programs that will limit the restriction of the respiratory function and thoracic stiffening in these children. Other measurements need to be carried out to confirm these initial results.

Based on real-world crash data and recent field studies, an ad-hoc group was set up in order to have a better comprehension of the effects of misuse of Child Restraint Systems (CRS) on child protection. A testing programme of 60 single misuse situations was conducted. Test results confirmed that, in frontal impact, children have higher risk of being injured on a number of different body regions when CRS’s are misused. This work provides material for educational and training purposes to help parents understand that child restraints need to be correctly fitted in order to provide the level of protection they are designed for.

Colloque Sécurité dans le transport, LAMEFIP ENSAM CER, BORDEAUX, FRANCE, 11-/10/2006 - 13/10/2006; Chaque jour 2 enfants sont tués sur les routes européennes et 200 sont blessés, ce qui représente un coût socio-économique élevé pour la Communauté Européenne. Les principaux segments corporels blessés sont la tête (30%), le thorax (30%) et l'abdomen (10%). Le fait d’observer une si faible réduction de la mortalité en dépit de l’utilisation de DRE (Dispositif de Retenue enfant – approuvé par la CEE) souligne l'importance d’une recherche continue dans le cadre de la sécurité de l’enfant. Bien que beaucoup d'initiatives aient été prises comme par exemple dans les projets en Europe, CREST(Child REstraint SysTem for cars, de janvier 1996 à décembre 2000) et CHILD (Advanced methods for improved Child safety, de septembre 2002 à septembre 2006), les marges de progression peuvent être considérées comme importantes. Le principal facteur contribuant à cette situation est le manque de connaissances biomécaniques spécifiques de l’enfant et les paramètres physiques associés. De part ce manque de connaissances, la bio-fidélité et la pertinence des réponses mécaniques de mannequins pour l’analyse d’accidents d’enfant, peuvent être améliorées comme dans les secteurs tels que la compliance thoracique et abdominale d'un enfant. La compliance thoracique et abdominale représente la capacité de déformation sous l'effet d’un chargement mécanique. Nous proposons de présenter dans ce papier le protocole et la faisabilité de mesurer cette raideur en observant des manipulations thoraciques et abdominales effectuées dans le cadre de traitements physiothérapiques. Le déplacement de la partie supérieure de la main et la charge appliquée par le praticien sont enregistrés. Une analyse tridimensionnelle est exécutée pour reconstruire les déplacements. L’analyse de plus d’observations en fonction de plusieurs variables comme par exemple l'âge, le sexe et l'anthropométrie sera réalisée ultérieurement. Par conséquent c'est seulement par une augmentation décisive des connaissances scientifiques que des avancées importantes pourront être réalisées vers des normes améliorées et une conception plus efficace des dispositifs de retenue enfant La pertinence de la recherche spécifique liée à l’enfant a été soulignée par le Groupe de Recherche du CNRS en « biomécanique des chocs » (GDR CNRS 2610) et à fait l’objet d’une demande de soutien au près de l’ANR au printemps 2006.

The 5th World Congress of Biomechanics, MUNICH, ALLEMAGNE, 29-/07/2006 - 04/08/2006

XXVII ème congrès de la société de biomécanique, VALENCIENNES, FRANCE, 12-/09/2002 - 13/09/2002; The protection of children involved in an accident is a difficult issue for various reasons, especially because of the lack of knowledge concerning the biomechanical behaviour and the tolerance to impact of this population. Impact biomechanics research on children is even more difficult than on adults because almost no experimental work can be done in this field.

Child dummies used in certification dynamic tests have not been improved since their marketing and their approval as European regulation dummies. Their main shortcoming lies in a too high and therefore unrealistic stiffness of the torso front part. This paper addresses a study carried out to solve this problem. It includes two parts. In a first section, the changes brought to the dummy torso and intended to improve its biofidelity and to reduce stiffness drastically are described. The lower part of the upper torso was remodelled, the pelvis profile was redefined, and the geometrical and mechanical characteristics of the foam used for the abdominal insert were changed. The results obtained using two transducers installed in the abdominal section are then presented. The measurement principle of the first transducer consists in a pressure measurement, and the principle of the second one in a load measurement. Modified dummy kinematics significantly differs from that of the standard dummy when the probability of submarining occurrence is high. Globally, the results recorded for the two transducers inserted in the abdominal section are similar for all tested configurations. The signals recorded are presented and interpreted to highlight clearly submarining occurrence conditions, and to better analyze injury mechanisms of the abdominal section. (A) For the covering abstract of the conference see IRRD 899572.

Over the past few years, the use of child restraint systems increases continuously in France. But, the accident logic data highlight that improvements are still necessary to decrease the frequency and the severity of cervical and abdominal injuries. In order to extend knowledge about lesional mechanisms of these two body segments numerous studies are undertaken to design transducers. This paper presents an intra-abdominal pressure transducer, designed and developed at the Laboratory of Impacts and Biomechanics of Inrets. For the covering abstract of the compendium see IRRD 880073.