Introduction Acute lower gastrointestinal bleeding (LGIB) presents challenges in emergency settings, with incidence influenced by demographic shifts and anticoagulant usage. The Oakland score aids in risk stratification for safe discharge based on clinical and laboratory parameters. However, external validation remains limited. Methods This study validated the Oakland score in a French cohort of patients with acute LGIB and assessed the discriminatory value of the score using the area under the curve (AUC) and then its sensitivity and specificity. Results A retrospective examination of 343 patient records that satisfied the inclusion criteria showed a median score of 14 points and good discriminatory capacity (area under the receiver operating characteristic (AUROC) curve: 0.83). There was low sensitivity (20.9%) for safe discharge but good specificity (98.5%) when using an 8-point threshold. With a 9-point threshold, the sensitivity was increased to 36.5%, while the specificity remained at 95%. Conclusion Identifying low-risk LGIB patients is accomplished without sacrificing sensitivity by increasing the Oakland score threshold to 9 points. This modification improves patient safety and resource allocation in the emergency room and has been verified by other large series. For wider implementation, additional validation and long-term outcome evaluations are required.

Entecavir treatment failure can be observed in compliant patients despite an absence of detectable resistance mutations by Pol/RT Sanger sequencing. We hypothesized that these unexplained treatment failures could rely on other mechanisms of viral resistance, especially on mutations selected outside of the Pol/RT domain. Partial virological response to entecavir was observed in three patients treated with immunosuppressive drugs, without selection of Pol/RT resistance mutations. Mutations selected in the whole HBV genome during entecavir treatment and potentially associated with resistance were searched for using deep sequencing and characterized using a phenotypic resistance assay. Mutations Q206K (pre-core/core), Q120K (pre-S1/pre-S2, T-cell epitope) and A300E (spacer domain) were selected during entecavir treatment in patient #1 but were not associated with an increased level of resistance to entecavir or an increase in HBV replication capacity. Core promoter mutations T1753G, A1762T and G1764A were present as major mutations before and after treatment in patient #1. HBs Ag immune escape mutations were present as major mutations before and after treatment in patients #2 (sK122R, sT126I, sP127S and sG145R) and #3 (sM133I). We demonstrated that PVR to entecavir does not require selection of any resistance mutation in the whole HBV genome. Our results demonstrate that major mutations can be selected outside of the Pol/RT domain before or during entecavir treatment. These mutations could contribute to entecavir treatment failure by other mechanisms than an increased level of resistance.

Far side has been identified in the literature as a potential cause of numerous injuries and fatalities. Euro NCAP developed a far side test protocol to be performed to assess adult protection. A monitoring phase was undertaken between January 2018 and December 2019, and the far side assessment will become part of the rating for all vehicles launched in 2020 onward. A test buck was developed and 6 paired WorldSID / Post Mortem Human Subjects (PMHS) were subjected to the test protocol proposed by Euro NCAP to contribute to the development of limits. The buck consisted of a rigid seat and a rigid central console covered with 50 mm of Ethafoam TM 180 with a density of 16 kg/m3. The buck was mounted on the sled with an angle of 75° between the X axis of the vehicle and the X axis of the sled. The peak head excursion was compared between PMHS and the WorldSID dummy. It was found reasonably similar. However, the dummy repeatability was found to be poor. Out of 6 tests conducted on 6 PMHS, 2 specimens sustained AIS3 and, 3 specimens AIS2 cervical spine injuries, 3 specimens sustained AIS3, 1 AIS2 and 1 AIS1 thoracic injuries, and 2 specimens sustained AIS2 abdominal injuries. The peak values recorded on the dummy according to the Euro NCAP protocol were compared with the injury assessments of the PMHS tests. In the configuration used, which includes a central console, the hard thorax injury prediction was found to be excellent. For the neck injury prediction, the data were merged with similar results available in the literature and an Injury Risk Curve was proposed as a derivative from the curve published by Mertz et al. (2003) for neck extension.

Several studies, available in the literature, were conducted to establish the most relevant criterion for predicting the thoracic injury risk on the THOR dummy. The criteria, such as the maximum deflection or a combination of parameters including the difference between the chest right and left deflections, were all developed based on given samples of Post Mortem Human Subject (PMHS). However, they were not validated against independent data and they are not always consistent with the observations from field data analysis. For this reason, 8 additional PMHS and matching THOR tests were carried out to assess the ability of the criteria to predict risks. Accident investigations showed that a reduction of the belt loads reduces the risk of rib fractures. Two configurations with different levels of force limitation were therefore chosen. A configuration representing an average European vehicle was chosen as a reference. It consists of a 3-point belt with a 3.5 kN and then 2 kN digressive limiter, combined with a 54-liter airbag. For better reproducibility and durability, the tests were performed with a pre-inflated bag and a semi-rigid seat. In this first configuration, the THOR dummy had a maximum resulting deflection of 43 mm. To differentiate the criteria, the second configuration was chosen such that it resulted in about the same deflection on the THOR dummy, but with a 5 kN belt force limitation combined with a lower pressure airbag. To reach this target of 43 mm, the pulse severity was lowered. Some criteria were higher in this second configuration, which allows them to be distinguished from the maximum deflection criterion. Four tests on four PMHS were performed in each configuration. The injury assessments showed that the total number of fractures was almost the same in both configurations, but that the number of separated fractures was greater in the 5 kN configuration. 25% of the subjects sustained AIS >3 injuries related to the number of displaced fractures in the 3.5/2 kN load limitation configuration. The result increased to 75% in the 5kN configuration. In total, 8 PMHS and the matching THOR tests were performed and used to assess the ability of the thoracic criteria to predict rib fractures in 2 types of chest loading configurations. The test results did not allow to conclude on the relevance of the criteria measured on the THOR dummy for the total number of rib fractures identified at autopsy (NFR). However, clearly different assessments for separated rib fractures (NSFR), make it possible to differentiate the criteria. The maximum resultant deflection failed to properly predict separated rib fractures while other criteria that include the left-to-right rib deflection difference did.

There are few experimental data in literature relating to femur cross-section moments in full-scale PMHS pedestrian tests. However, these moments are used as injury criteria to evaluate pedestrian protection. This study aimed to provide this type of data. In previous studies by the authors, 15 post-mortem human subject (PMHS) were impacted by four different generic simplified vehicle bucks (two sedans, a SUV and a van). Each PMHS was instrumented with three mono-axis strain gauges on its right femur (impacted before the left femur). To derive the moments in the femur from these strain measurements, three-point bending tests were performed on the femurs isolated from the corresponding PMHS tested. The moment-strain relationship for each strain measurement location was then established for each femur. By applying these relationships to the strains measured in the full-scale PMHS tests, the corresponding cross-section moments on the femur were derived. Finally, by scaling these moments, biofidelity corridors were established for the 50th percentile male pedestrian in terms of upper, middle and lower cross-section moments in the femur, and for four vehicle profiles. These corridors will allow assessing biofidelity of human body models, physical dummies and lower extremity impactors.

The EuroSID-2re (ES-2re) Anthropomorphic Test Device (ATD) commonly known as the crash test dummy is also used in the military domain to assess the risk of injury of armored vehicles occupants from lateral impact. The loading conditions range from low velocity - long duration impacts (4 m/s - 50 ms) similar to the automotive domain, to high velocity - short duration impacts (28 m/s - 3 ms) corresponding to cases where the panel deforms under an explosion. The human shoulder response to lateral impact was investigated at bounds of the loading condition spectrum previously mentioned, and also at intermediate conditions (14 m/s - 9 ms) in previous studies. The aim of the current study is to provide additional insight at the intermediate loading conditions which are not found in the literature. Eight pure lateral shoulder impact tests were performed on Post Mortem Human Subjects (PMHS) using an 8.1 kg rigid impactor at velocities ranging from 3.3 m/s to 8.8 m/s with the duration ranging from 25 ms to 35 ms. The PMHS were instrumented with accelerometers attached to the sternum, and the upper thoracic spine (T1 vertebra). Strain gages were glued onto the right and left clavicles and ribs 2 to 6. The shoulder force was measured at the interface with the impactor and the impact was filmed by high speed cameras (5000 fps) to track the YZ displacements of the impactor, T1 vertebra, and sternum in the laboratory frame. Three shoulders out of the eight sustained AIS 2 injuries which included a clavicle fracture. The impactor forces ranged from 1200 to 4600 N. The PMHS accelerations ranged from 44 to 163 g at the sternum, and from 17 to 60 g at the T1 vertebra. The analysis of the strain gage signals revealed that the clavicle fractures occurred at the beginning of the impact and coincided with a peak force. An estimate of the acromion-to-shoulder compression (Cmax) was computed. It ranged from 0% to 15% for the non-injured shoulders, and from 19% to 28% for the injured shoulders. This new PMHS test series will be used in a future work to develop a shoulder injury criterion for the ES-2re ATD that is relevant for the whole loading conditions spectrum of the military domain.

In the last decade, extensive efforts have been made to understand the physics of submarining and its consequences in terms of abdominal injuries. For that purpose, 27 Post Mortem Human Subject (PMHS) tests were performed in well controlled conditions on a sled and response corridors were provided to assess the biofidelity of dummies or human body models. All these efforts were based on the 50th percentile male. In parallel, efforts were initiated to transfer the understanding of submarining and the prediction criteria to the THOR dummies. Both the biofidelity targets and the criteria were scaled down from the 50th percentile male to the 5th percentile THOR female. The objective of this project was to run a set of reference PMHS tests in order to check the biofidelity of the THOR F05 in terms of submarining. Three series of tests were performed on nine PMHS, the first one was designed to avoid submarining, the second and third ones were designed to result in submarining. In the first configuration, no submarining was observed in 3 cases out of 4 and only one iliac wing fracture occurred in one subject. In the second and third configurations, all subjects but one sustained submarining. In addition, two subjects out of three in the third configuration sustained substantial iliac wing fractures. Nevertheless, all configurations can be represented by at least one or several cases without any pelvis fracture. Corridors were constructed for the external forces and the PMHS kinematics. They are provided in this paper as new experimental references to assess the biofidelity of small female human surrogates in different configurations where submarining did or did not occur.

This study aims to provide a set of reference post-mortem human subject tests which can be used, with easily reproducible test conditions, for developing and/or validating pedestrian dummies and computational human body models against a road vehicle. An adjustable generic buck was first developed to represent vehicle front-ends. It was composed of four components: two steel cylindrical tubes screwed on rigid supports in V-form represent the bumper and spoiler respectively, a quarter of a steel cylindrical tube represents the bonnet leading edge, and a steel plate represents the bonnet. These components were positioned differently to represent three types of vehicle profile: a sedan, a SUV and a van. Eleven post-mortem human subjects were then impacted laterally in a mid-gait stance by the bucks at 40 km/h: three tests with the sedan, five with the SUV, and three with the van. Kinematics of the subjects were recorded via high speed videos, impact forces between the subjects and the bucks were measured via load cells behind each tube, femur and tibia deformation and fractures were monitored via gauges on these bones. Based on these tests, biofidelity corridors were established in terms of: 1) displacement time history and trajectory of the head, shoulder, T1, T4, T12, sacrum, knee and ankle, 2) impact forces between the subjects and the buck. Injury outcome was established for each PMHS via autopsy. Simplicity of its geometry and use of standard steel tubes and plates for the buck will make it easy to perform future, new post-mortem human subject tests in the same conditions, or to assess dummies or computational human body models using these reference tests.

The aim of this study was to investigate the sacroiliac joint injury mechanism. Two test configurations were selected from full scale car crashes conducted with the WorldSID 50th dummy resulting in high sacroiliac joint loads and low pubic symphysis force, i.e. severe conditions for the sacroiliac joint. The two test conditions were reproduced in laboratory using a 150-155 kg guided probe propelled respectively at 8 m/s and 7.5 m/s and with different shapes and orientations for the plate impacting the pelvis. Nine Post Mortem Human Subject (PMHS) were tested in each of the two configurations (eighteen PMHS in total). In order to get information on the time of fracture, eleven strain gauges were glued on the pelvic bone of each PMHS. Results - In the first configuration, five PMHS out of nine sustained AIS2+ pelvic injuries. All five presented sacroiliac joint injuries associated with pubic area injuries. In the second configuration, four specimens out of nine sustained AIS2+ pelvic injuries. Two of them presented sacroiliac joint fractures associated with pubic area injuries. The other two presented injuries at the pubic area and acetabulum only. The strain gauges signals suggested that the pubic fractures occurred before the sacroiliac joint fractures in the great majority of the cases (five cases out of seven). Conclusions - Even in the oblique impact conditions of the present study, the pubic symphysis area was observed to be the weakest zone of the pelvis and its failure the predominant cause of sacroiliac joint injuries. It was hypothesized that the failure of the pubic rami allowed the hemi-pelvis to rotate inward, and that this closing-book motion induced the failure of the sacroiliac joint.

La definition du porteur inactif du virus de l’hepatite B (VHB) repose sur des mesures repetees des transaminases et de la charge virale B pendant au moins 1 an. Les transaminases ALT doivent etre rigoureusement normales et la charge virale B < 20 000 UI/mL. Ce statut correspond a un controle immunologique de l’infection par le patient infecte et est associe a un bon pronostic, avec tres faible risque d’evolution vers la cirrhose et le cancer. Cette situation peut toutefois etre confondue avec une hepatite B chronique a anticorps anti-HBe en phase de quiescence. D’autre part, des comorbidites (alcool, tabac, syndrome metabolique) peuvent favoriser le developpement de la fibrose hepatique chez des porteurs inactifs du VHB. Ces patients necessitent donc une surveillance prolongee. La place des tests non invasifs de fibrose, de l’echographie hepatique, de la quantification de l’antigene HBs (Ag HBs) ou de l’antigene HB core-related (HBcr) reste a preciser dans cette surveillance. Une meilleure evaluation de leurs apports respectifs permettra peut-etre a l’avenir de distinguer des sujets a faible risque, dont la surveillance pourra etre allegee, de sujets a risque majore, meritant une surveillance soutenue.

Sled tests focused on pelvis behavior and submarining can be found in the literature. However, they were performed either with rigid seats or with commercial seats. The objective of this study was to get reference tests to assess the submarining ability of dummies in more realistic conditions than on rigid seat, but still in a repeatable and reproducible setup. For this purpose, a semi-rigid seat was developed, which mimics the behavior of real seats, although it is made of rigid plates and springs that are easy to reproduce and simulate with an FE model. In total, eight PMHS sled tests were performed on this semirigid seat to get data in two different configurations: first in a front seat configuration that was designed to prevent submarining, then in a rear seat configuration with adjusted spring stiffness to generate submarining. All subjects sustained extensive rib fractures from the shoulder belt loading. No pelvis fractures and no submarining were observed in the front seat configuration, but two subjects sustained lumbar vertebrae fractures. In the rear seat configuration, all subjects sustained pelvic fractures and demonstrated submarining. Corridors were constructed for the external forces and the PMHS kinematics. They are provided in this paper as new reference tests to assess the biofidelity of human surrogates in different configurations that either result in submarining or do not. In future, it is intended to analyze further seat and restraint system configurations to be able to define a submarining predictor.

Nine Post Mortem Human Subject (PMHS) tests were published by Luet et al. (2012) as a reference for submarining assessment. These tests suffered limitations, however, due to the rigid characteristics of the seat. The objective of this study is to assess the submarining ability of existing dummies in more realistic conditions, i.e. on a real seat. In total, nine PMHS sled tests were performed on a real seat to procure data in 3 different configurations. The tests were also duplicated with HII, HIII and THOR Mod Kit dummies to evaluate their behaviour in comparison to corridors built with 3 PMHS each. The external forces, the pelvis kinematics and the injury assessments are provided here. The dummy responses are compared to the PMHS corridors. No submarining was observed in the standard configuration. Iliac crest fractures and submarining were observed in the slouched position intended to generate submarining. Finally, for two subjects out of three, no iliac wing fracture and no submarining were observed in the slouched position with a lap‐belt load limitation at 4 kN and a pretension system.

UNLABELLED The WorldSID dummy can be equipped with both a pubic and a sacroiliac joint (S-I joint) loadcell. Although a pubic force criterion and the associated injury risk curve are currently available and used in regulation (ECE95, FMVSS214), as of today injury mechanisms, injury criteria, and injury assessment reference values are not available for the sacroiliac joint itself. The aim of this study was to investigate the sacroiliac joint injury mechanism. Three configurations were identified from full-scale car crashes conducted with the WorldSID 50th percentile male where the force passing through the pubis in all three tests was approximately 1500 N while the sacroiliac Fy/Mx peak values were 4500 N/50 Nm, 2400 N/130 Nm, and 5300 N/150 Nm, respectively. These tests were reproduced using a 150 kg guided probe impacting Post Mortem Human Subjects (PMHS) at 8 m/s, 5.4 m/s and 7.5 m/s. The shape and the orientation of the impacting face of the probe were selected to match the WorldSID pubic Fy and sacroiliac Fy/Mx loads of the three vehicle test configurations. Three PMHS were tested in each of the three configurations (nine PMHS in total). RESULTS In the first PMHS configuration, one specimen sustained an AIS 3 injury and one sustained an AIS 4 injury (an unstable pelvis with complete disruption of the posterior arch, a sacroiliac joint disruption associated with an iliac fracture, and a pubic symphysis separation). In the second configuration, all specimens sustained a fracture of the superior lateral iliac wing (AIS 2). In the third configuration, one specimen sustained a partial disruption of the anterior arch (AIS 2). Based on the data from strain gauges located on the pubic rami and near the sacroiliac joint, the pubic rami fractures were identified as occurring prior to the sacroiliac fractures. CONCLUSIONS Out of nine impactor tests performed, the PMHS S-I joint injuries were observed to consistently be associated with pelvic anterior arch fractures. In addition, from the injury sequences derived from strain gauges located on the specimen pelvises and on the injury assessments obtained by necropsy, the S-I joint fractures were observed to occur after the anterior arch fractures.

In the ECE 127 Regulation on pedestrian leg protection, as well as in the Euro NCAP test protocol, a legform impactor hits the vehicle at the speed of 40 kph. In these tests, the knee is fully extended and the leg is not coupled to the upper body. However, the typical configuration of a pedestrian impact differs since the knee is flexed during most of the gait cycle and the hip joint applies an unknown force to the femur. This study aimed at investigating the influence of the inertia of the upper body (modelled using an upper body mass fixed at the proximal end of the femur) and the initial knee flexion angle on the lower limb injury outcome. In total, 18 tests were conducted on 18 legs from 9 Post Mortem Human Subjects (PMHS). The principle of these tests was to impact the leg at 40 kph using a sled equipped with 3 crushing steel tubes, the stiffness of which were representative of the front face of a European sedan (bonnet leading edge, bumper and spoiler). The mass of the equipped sled was 74.5 kg. The test matrix was designed to perform 4 tests in 4 configurations combining two upper body masses (either 0 or 3 kg) and two knee angles (0 or 20 degrees) at 40 kph (11 m/s) plus 2 tests at 9 m/s. Autopsies were performed on the lower limbs and an injury assessment was established. The findings of this study were first that the increase of the upper body mass resulted in more severe injuries, second that an initial flexion of the knee, corresponding to its natural position during the gait cycle, decreased the severity of the injuries, and third that based on the injury outcome, a test conducted with no upper body mass and the knee fully extended was as severe as a test conducted with a 3 kg upper body mass and an initial knee flexion of 20°.

Despite the increasing knowledge of the thorax mechanics in impact loadings, the effects of inter-individual differences on the mechanical response are difficult to take into account. For example, the biofidelity corridors for the small female or large male are extrapolated from the midsize male corridors. The present study reports on the results of new tests performed on small female Post Mortem Human Subjects (PMHS), and compares them with test results on midsize male PMHS. Three tests in pure side impact and three tests in forward oblique impact were performed on the thorax of small female specimens. The average weight and stature were 43 kg and 1.58 m for the small female specimens. The initial speed of the impactor was 4.3 m/s. The mass and the diameter of the impactor face were respectively 23.4 kg and 130 mm. The instrumentation and methodology was the same as for the tests published in 2008 by Trosseille et al. on midsize male specimens. The rib cages were instrumented with accelerometers on the T1, T4 and T12 vertebrae, upper and lower sternum, and the ribs were instrumented with up to 110 strain gauges. A force transducer and an accelerometer were mounted on the impactor in order to record the force applied onto the thorax. Targets fixed on vertebrae were tracked using high speed cameras in order to estimate the thoracic deflection. For the six midsize males, the test conditions were exactly the same as for the small female specimens, except for the diameter of the impactor face which was 152 mm. The average weight and stature were 70.3 kg and 1.70 m for the midsize male specimens. The force and thoracic deflection time-histories and the injury assessments are given for each specimen. The thorax force magnitude varied from 1.05 to 1.45 kN and from 1.63 to 2.34 kN, respectively for the small female and midsize male groups. The maximum deflection varied from 51 to 117 mm and from 59 to 81 mm, respectively for the small female and midsize male groups. The maximum forces appeared to be a function of the total body mass for each loading angle.

A specific test setup was designed to recreate in a laboratory the features of a deforming armoured sidewall of a military veh icle submitted to an Improvised Explosive Device (IED) blast. A free moving impactor of 7 kg weight and 10 cm diameter contact face was propelled at 27 m/s and decelerated over 4 cm using copper tubes in order to control the penetration. Four tests on ES-2re 50 th percentile dummy were performed to check on the similarity of the impact with an IED blast case. The Y shoulder force sensor time history signals were similar to ones recorded in full-scale IED blast tests. Six tests on Post Mortem Human Subjects were performed at different violence levels. The PMHS maximum deflection s (from shoulder edge to sternum) and reaction force ranged from 3.2 cm to 4.7 cm, and from 5.7 kN to 11.7 kN, respectively. The three PMHS tests on which the highest forces were recorded presented moderate injury (AIS2) on the 2005 Abbreviated Injury Scale. Injuries were mainly humerus fractures (shaft and head). One subjec t sustained multiple fractures of the scapula. These results presented different features from those of previous studies that used lower impact rates (below 7 m/s). These results could be used to develop an AIS2+ shoulder injury criterion specific to these kinds of military impacts, using the ES-2re dummy.

This study focused on a better understanding and characterization of the submarining phenomenon that occurs in frontal crashes when the lap belt slides over the anterior superi or iliac spine. Submarining is the consequence of the pelvis kinematics relative to the lap belt, driven by the equilibrium of forces and moments applied to the pelvis. The study had two primary purposes; the first was to provide new PMHS data in submarining test configurations, the second was to investigate the Hybrid II and Hybrid III dummies biofidelity regarding submarining. Several Post Mortem Human Subject (PMHS) studies have been published on this subject. However, the lack of information about the occupant initial positioning and the use of car seats make it difficult to reconstruct these tests. Furthermore, the two dummies are rarely compared to PMHS in submarining test configurations. A fifteen frontal sled test campaign was carried out on two Anthropomorphic Test Devices (ATDs) and nine PMHS. The test environment was designed to be reproducible. It consisted of a rigid seat, a 2-poi nts shoulder belt and a 2-points lap belt instrumented to record their 3D forces at anchorage. The subjects were instrumented with angular sensors at the sacrum, T1 and T12 levels to record their initial angles. Kinematics was measured at these three levels by means of three accelerometers and angular velocity sensors. A PMHS positioning procedure was developed to ensure repeatability. A pre-test was performed on each subject to characterize its lumbar spine static behavior. All the subjects were CT-scanned from head to toe prior to the test. The campaign was divided into three test configurations leading to different surrogates' interaction with the environment and different kinematics. This resulted in a wider range of behaviors for the dummies evaluation. The deceleration pulse, initial lap belt angle, lap belt slack, seat pan angle and footrest position varied. The Hybrid II and Hybrid III dummies and three PMHS were tested in each configuration. Forces and kinematics time history corridors based on the PMHS responses are provided for each configuration. The dummies' responses are evaluated against these targets. For the first configuration (40 km/h), the peak lap belt tension for both sides was between 3,000 N and 6,385 N for the three PMHS while it was around 4,700 N and 6,200 N in average for Hybrid II and Hybrid III respectively. The maximum pelvic rotation ranged from 41° to 80° for the PMHS and reached approximately 45° for the two dummies. For the other two configurations (50 km/h), the peak lap belt tension varied from 3,660 N to 7,180 N for the PMHS and was between 5,400 N and 6,100 N for Hybrid II and between 7,145 N and 7,900 N for Hybrid III. The maximum pelvic rotation ranged from 43° to 73° for the PMHS, while it reached approximately 54° and 46° for Hybrid II and Hybrid III respectively.

Occupant protection in rear impact involves two competing challenges. On one hand, allowing a deformation of the seat would act as an energy absorber in low severity impacts and would consequently decrease the risk of neck injuries. However, on the other hand, large deformations of the seat may increase the likelihood of occupant ejection in high severity cases. Green et al. 1987 analyzed a total of 919 accidents in Great Britain. They found that occupant ejection resulted in a risk of severe injuries and fatalities between 3.6 and 4.5 times higher than those cases where no ejection was observed. The sample included single front, side and rear impacts as well as multiple impacts and rollover. The rate of belt use in the sample was 50%. While this analysis included all forms of impact scenarios, nevertheless, it highlights the relative injury severity of occupant ejection. Extensive literature search has found no full-scale rear impact tests involving Post Mortem Human Subjects (PMHS) conducted in a laboratory environment and resulting in ejection. This paper describes a total of 10 sled tests conducted on 3 belted PMHS using a simplified seat design composed of rigid plates assembled such that the angular and linear stiffness of the seatback (including the foam) was modeled. The initial angular position and the range of motion of the seatback, the size of the PMHS, the slack length of the seatbelt, the angular stiffness of the seatback, and the use of headrest were varied in the test matrix while the pulse was kept constant (triangular acceleration with a peak of 17 G at 30 ms and a duration of 95 ms). In the test series, the tests were not run randomly but the likelihood of occupant ejection was increased systematically until ejection occurred. PMHS seat ejection was observed only for the 95th percentile, initially positioned with a seatback angle relative to the vertical equal to 22°, a range of seatback angular motion equal to 44° and no headrest. Repeating the test under the same conditions but with the pretentionner fired did not prevent the ejection. In addition, the 50th percentile belted specimen were not observed to sustain rearward seat ejection under realistic conditions including the use of head-rest.