Methodology for Evaluation of WIAMan Injury Assessment Reference Curves Using Whole Body Match-Paired Data.

Development of the Warrior Injury Assessment Manikin (WIAMan) capability has included the creation of injury assessment reference curves (IARCs) specific to under-body blast (UBB) loading mechanisms and injuries. The WIAMan IARCs were created from high-rate vertical loading tests of component post-mortem human surrogates (PMHS) and analogous components of the WIAMan anthropomorphic test device (ATD). Validation of the WIAMan IARCs is required prior to the WIAMan ATD being utilized for injury assessment in live-fire vehicle test events. A portion of the validation process involves evaluating the ability of the IARCs to predict injury at the system level (whole body). This study evaluates a methodology to assess the performance of the WIAMan IARCs using match-paired tests of whole body PMHS and the WIAMan ATD. The methodology includes a qualitative analysis designed to identify false-positive and false-negative ATD predictions, as well as a quantitative analysis that utilizes area under the receiver-operating characteristic curve (AROC) and Brier score indices to grade IARC performance. Three WIAMan IARCs were used to exemplify the proposed methodology and results are provided. Attributes of the false-prediction, AROC, and Brier score portions of the methodology are presented, with results indicating the new methodology is thorough and robust in evaluation of IARCs.

Quantifying the Effect of Pelvis Fracture on Lumbar Spine Compression during High-rate Vertical Loading.

Fracture to the lumbo-pelvis region is prevalent in warfighters seated in military vehicles exposed to under-body blast (UBB). Previous high-rate vertical loading experimentation using whole body post-mortem human surrogates (PMHS) indicated that pelvis fracture tends to occur earlier in events and under higher magnitude seat input conditions compared to lumbar spine fracture. The current study hypothesizes that fracture of the pelvis under high-rate vertical loading reduces load transfer to the lumbar spine, thus reducing the potential for spine fracture. PMHS lumbo-pelvis components (L4-pelvis) were tested under high-rate vertical loading and force and acceleration metrics were measured both inferior-to and superior-to the specimen. The ratio of inferior-tosuperior responses was significantly reduced by unstable pelvis fracture for all metrics and a trend of reduced ratio was observed with increased pelvis AIS severity. This study has established that pelvis fracture reduces compression forces at the lumbar spine during high-rate vertical loading, thus reducing the potential for fracture to the lumbar spine. Therefore, pelvis injury potential should be considered when implementing lumbar injury criteria specific to UBB.

Blind tracheal intubation by paramedics through the LMA-Unique.

OBJECTIVE: The manufacturer of the laryngeal mask airway (LMA) reports success rates of 30-93% by practitioners attempting tracheal intubation through the LMA-Classic. No prior studies describe success rates through the (disposable) LMA-Unique by paramedics. The objective of this study was to measure the success rate of paramedics attempting to intubate the trachea blindly through the LMA-Unique. METHODS: During a paramedic refresher class and an emergency medical services teaching day conference, paramedics previously trained in the use of the LMA-Unique as a "rescue" airway device were instructed in the technique of tracheal intubation through the LMA-Unique. A Laerdal LMA-mannequin was immobilized with an extrication collar and held by an investigator in the head-neutral position. Paramedics were first asked to insert the LMA-Unique as previously trained, and to confirm adequate ventilation by seeing inflation of the mannequin's lungs. Then, subjects were asked to pass a well-lubricated 6-0 Mallinckrodt endotracheal tube through the LMA-Unique within a 60-second period. Tracheal placement of the endotracheal tube was then confirmed by visualization of the expanding mannequin lungs. Rates of success of LMA-Unique placement and endotracheal tube placement were measured. RESULTS: Fifty of the 52 (96%; CI 91% to 100%) paramedics successfully inserted the LMA-Unique on the first attempt. Only 11 of the 52 (21%; CI 10% to 32%) paramedics were successful in blind placement of the endotracheal tube into the trachea through the LMA-Unique within a 60-second period. The failures (41 of the 52) were visually confirmed to be located in the esophagus. CONCLUSION: In this study, when attempting blind tracheal intubation through the LMA-Unique, paramedics were rarely successful in tracheal placement. Basic LMA-Unique insertion, however, had a very high success rate.

Incidence of complications for subtotal ionized field ablation of the tonsils.

OBJECTIVE: Ionized field ablation, or coblation-assisted subtotal tonsillectomy, has been described as a new alternative technique for the management of tonsillar disease. This study was designed to review the incidence of complications in patients undergoing this procedure. STUDY DESIGN: A 10-surgeon retrospective chart review of the intraoperative and postoperative complications of patients undergoing ionized field ablation subtotal removal of tonsils was performed. Postoperative pain, dietary restrictions, and activity level were not reviewed. RESULTS: Of the 528 patients who underwent ionized field ablation of their tonsils, the incidence of intraoperative and postoperative complications compared favorably with those reported in retrospective studies in the literature for traditional subcapsular tonsillectomy. Significant postoperative bleeding occurred in less than 1%, and only 1 patient required surgical control of bleeding in the operating room. No patients required transfusions of any blood products. CONCLUSIONS: Ionized field ablation subtotal tonsillectomy may offer an alternative to traditional subcapsular tonsillar surgery with a decreased incidence of postoperative complications. Further study is necessary to establish the complication rate of this technique.