Post-mortem computed tomography assessment of medical support device position following fatal trauma: a single-center experience.

PURPOSE: To evaluate the percentage of misplaced medical support lines and tubes in deceased trauma patients using post-mortem computed tomography (PMCT). METHODS: Over a 9-year period, trauma patients who died at or soon after arrival in the emergency department were candidates for inclusion. Whole body CT was performed without contrast with support medical devices left in place. Injury severity score (ISS) was calculated by the trauma registrar based on the injuries identified on PMCT. The location of support medical devices was documented in the finalized radiology reports. RESULTS: A total of 87 decedents underwent PMCT, of which 69% (n = 60) were male. For ten decedents, the age was unknown. For the remaining 77 decedents, the average age was 48.4 years (range 18-96). The average ISS for the cohort was 43.4. Each decedent had an average of 3.3 support devices (2.9-3.6, 95% CI), of which an average of 1 (31.3%, 0.8-1.2, 95% CI) was malpositioned. A total of 60 (69.0%) had at least one malpositioned medical support device. The most commonly malpositioned devices were decompressive needle thoracostomies (n = 25/32, 78.1%). The least malpositioned devices were intraosseous catheters (n = 7/69, 10.1%). Nearly one quarter (n = 19/82, 23.2%) of mechanical airways were malpositioned, including 4.9% with esophageal intubation. CONCLUSION: Malpositioned supportive medical devices are commonly identified on post-mortem computed tomography trauma decedents, seen in 69.0% of the cohort, including nearly one quarter with malpositioned mechanical airways. Post-mortem CT can serve as a useful adjunct in the quality improvement process by providing data for education of trauma and emergency physicians and first responders.

Inferior collicular cells that project to the auditory thalamus are increasingly surrounded by perineuronal nets with age.

The age-related loss of GABA in the inferior colliculus (IC) likely plays a role in the development of age-related hearing loss. Perineuronal nets (PNs), specialized aggregates of extracellular matrix, increase with age in the IC. PNs, associated with GABAergic neurotransmission, can stabilize synapses and inhibit structural plasticity. We sought to determine whether PN expression increased on GABAergic and non-GABAergic IC cells that project to the medial geniculate body (MG). We used retrograde tract-tracing in combination with immunohistochemistry for glutamic acid decarboxylase and Wisteria floribunda agglutinin across three age groups of Fischer Brown Norway rats. Results demonstrate that PNs increase with age on lemniscal and non-lemniscal IC-MG cells, however two key differences exist. First, PNs increased on non-lemniscal IC-MG cells during middle-age, but not until old age on lemniscal IC-MG cells. Second, increases of PNs on lemniscal IC-MG cells occurred on non-GABAergic cells rather than on GABAergic cells. These results suggest that synaptic stabilization and reduced plasticity likely occur at different ages on a subset of the IC-MG pathway.

The Density of Perineuronal Nets Increases With Age in the Inferior Colliculus in the Fischer Brown Norway Rat.

Age-related hearing loss, one of the most frequently diagnosed disabilities in industrialized countries, may result from declining levels of GABA in the aging inferior colliculus (IC). However, the mechanisms of aging and subsequent disruptions of temporal processing in elderly hearing abilities are still being investigated. Perineuronal nets (PNs) are a specialized form of the extracellular matrix and have been linked to GABAergic neurotransmission and to the regulation of structural and synaptic plasticity. We sought to determine whether the density of PNs in the IC changes with age. We combined Wisteria floribunda agglutinin (WFA) staining with immunohistochemistry to glutamic acid decarboxylase in three age groups of Fischer Brown Norway (FBN) rats. The density of PNs on GABAergic and non-GABAergic cells in the three major subdivisions of the IC was quantified. Results first demonstrate that the density of PNs in the FBN IC increase with age. The greatest increases of PN density from young to old age occurred in the central IC (67% increase) and dorsal IC (117% increase). Second, in the young IC, PNs surround non-GABAergic and GABAergic cells with the majority of PNs surrounding the former. The increase of PNs with age in the IC occurred on both non-GABAergic and GABAergic populations. The average density of PN-surrounded non-GABAergic cells increased from 84.9 PNs/mm2 in the young to 134.2 PNs/mm2 in the old. While the density of PN-surrounded GABAergic cells increased from 26 PNs/mm2 in the young to 40.6 PNs/mm2 in the old. The causality is unclear, but increases in PN density in old age may play a role in altered auditory processing in the elderly, or may lead to further changes in IC plasticity.