Outcomes and potential for improvement in the prehospital treatment of penetrating chest injuries in a European metropolitan area: A retrospective analysis of 2009 - 2017

BACKGROUND

Trauma is the leading cause of death in patients <45 years living in high-resource settings. However, penetrating chest injuries are still relatively rare in Europe - with an upwards trend. These cases are of particular interest to emergency medical services (EMS) due to available invasive treatment options like chest tube placement or resuscitative thoracotomy. To date, there is no sufficient data from Austria regarding penetrating chest trauma in a metropolitan area, and no reliable source to base decisions regarding further skill proficiency training on.

METHODS

For this retrospective observational study, we screened all trauma emergency responses of the Viennese EMS between 01/2009 and 12/2017 and included all those with a National Advisory Committee for Aeronautics (NACA) score ≥ IV (= potentially life-threatening). Data were derived from EMS mission documentations and hospital files, and for those cases with the injuries leading to cardiopulmonary resuscitation (CPR), we assessed the EMS cardiac arrest registry and consulted a forensic physician.

RESULTS

We included 480 cases of penetrating chest injuries of NACA IV-VII (83% male, 64% > 30 years old, 74% stab wounds, 16% cuts, 8% gunshot wounds, 56% inflicted by another party, 26% self-inflicted, 18% unknown). In the study period, the incidence rose from 1.4/100,000 to 3.5/100,000 capita, and overall, about one case was treated per week. In the cases with especially severe injury patterns (= NACA V-VII, 43% of total), (tension-)pneumothorax was the most common injury (29%). The highest mortality was seen in injuries to pulmonary vessels (100%) or the heart (94%). Fifty-eight patients (12% of total) deceased, whereas in 15 cases, the forensic physician stated survival could theoretically have been possible. However, only five of these CPR patients received at least unilateral thoracostomy. Regarding all penetrating chest injuries, thoracostomy had only been performed in eight patients.

CONCLUSIONS

Severe cases of penetrating chest trauma are rare in Vienna and happened about once a week between 2009 and 2017. Both incidence and case load increased over the years, and potentially life-saving invasive procedures were only reluctantly applied. Therefore, a structured educational and skill retention approach aimed at both paramedics and emergency physicians should be implemented.

TRIAL REGISTRATION

Retrospective analysis without intervention.

Multifactorial White Matter Damage in the Acute Phase and Pre-Existing Conditions May Drive Cognitive Dysfunction after SARS-CoV-2 Infection: Neuropathology-Based Evidence

BACKGROUND

There is an urgent need to better understand the mechanisms underlying acute and long-term neurological symptoms after COVID-19. Neuropathological studies can contribute to a better understanding of some of these mechanisms.

METHODS

We conducted a detailed postmortem neuropathological analysis of 32 patients who died due to COVID-19 during 2020 and 2021 in Austria.

RESULTS

All cases showed diffuse white matter damage with a diffuse microglial activation of a variable severity, including one case of hemorrhagic leukoencephalopathy. Some cases revealed mild inflammatory changes, including olfactory neuritis (25%), nodular brainstem encephalitis (31%), and cranial nerve neuritis (6%), which were similar to those observed in non-COVID-19 severely ill patients. One previously immunosuppressed patient developed acute herpes simplex encephalitis. Acute vascular pathologies (acute infarcts 22%, vascular thrombosis 12%, diffuse hypoxic-ischemic brain damage 40%) and pre-existing small vessel diseases (34%) were frequent findings. Moreover, silent neurodegenerative pathologies in elderly persons were common (AD neuropathologic changes 32%, age-related neuronal and glial tau pathologies 22%, Lewy bodies 9%, argyrophilic grain disease 12.5%, TDP43 pathology 6%).

CONCLUSIONS

Our results support some previous neuropathological findings of apparently multifactorial and most likely indirect brain damage in the context of SARS-CoV-2 infection rather than virus-specific damage, and they are in line with the recent experimental data on SARS-CoV-2-related diffuse white matter damage, microglial activation, and cytokine release.

First-order convergence of Milstein schemes for McKean-Vlasov equations and interacting particle systems

In this paper, we derive fully implementable first-order time-stepping schemes for McKean-Vlasov stochastic differential equations, allowing for a drift term with super-linear growth in the state component. We propose Milstein schemes for a time-discretized interacting particle system associated with the McKean-Vlasov equation and prove strong convergence of order 1 and moment stability, taming the drift if only a one-sided Lipschitz condition holds. To derive our main results on strong convergence rates, we make use of calculus on the space of probability measures with finite second-order moments. In addition, numerical examples are presented which support our theoretical findings.

Systematic Radiation Dose Reduction in Cervical Spine CT of Human Cadaveric Specimens: How Low Can We Go?

BACKGROUND AND PURPOSE

While the use of cervical spine CT in trauma settings has increased, the balance between image quality and dose reduction remains a concern. The purpose of our study was to compare the image quality of CT of the cervical spine of cadaveric specimens at different radiation dose levels.

MATERIALS AND METHODS

The cervical spine of 4 human cadavers (mean body mass index; 30.5 ± 5.2 kg/m²; range, 24-36 kg/m²) was examined using different reference tube current-time products (45, 75, 105, 135, 150, 165, 195, 275, 355 mAs) and a tube voltage of 120 kV(peak). Data were reconstructed with filtered back-projection and iterative reconstruction. Qualitative image noise and morphologic characteristics of bony structures were quantified on a Likert scale. Quantitative image noise was measured. Statistics included analysis of variance and the Tukey test.

RESULTS

Compared with filtered back-projection, iterative reconstruction provided significantly lower qualitative (mean noise score: iterative reconstruction = 2.10/filtered back-projection = 2.18; P = .003) and quantitative (mean SD of Hounsfield units in air: iterative reconstruction = 30.2/filtered back-projection = 51.8; P < .001) image noise. Image noise increased as the radiation dose decreased. Qualitative image noise at levels C1-4 was rated as either "no noise" or as "acceptable noise." Any shoulder position was at level C5 and caused more artifacts at lower levels. When we analyzed all spinal levels, scores for morphologic characteristics revealed no significant differences between 105 and 355 mAs (P = .555), but they were worse in scans at 75 mAs (P = .025).

CONCLUSIONS

Clinically acceptable image quality of cervical spine CTs for evaluation of bony structures of cadaveric specimens with different body habitus can be achieved with a reference mAs of 105 at 120 kVp with iterative reconstruction. Pull-down of shoulders during acquisition could improve image quality but may not be feasible in trauma patients with unknown injuries.

Dissecting the effect of chemical additives on the enzymatic hydrolysis of pretreated wheat straw

Chemical additives were examined for ability to increase the enzymatic hydrolysis of thermo-acidically pretreated wheat straw by Trichoderma reesei cellulase at 50 °C. Semi-empirical descriptors derived from the hydrolysis time courses were applied to compare influence of these additives on lignocellulose bioconversion on a kinetic level, presenting a novel view on their mechanism of action. Focus was on rate retardation during hydrolysis, substrate conversion and enzyme adsorption. PEG 8000 enabled a reduction of enzyme loading by 50% while retaining the same conversion of 67% after 24h. For the first time, a beneficial effect of urea is reported, increasing the final substrate conversion after 48 h by 16%. The cationic surfactant cetyl-trimethylammonium bromide (CTAB) enhanced the hydrolysis rate at extended reaction time (rlim) by 34% and reduced reaction time by 28%. A combination of PEG 8000 and urea increased sugar release more than additives used individually.

Enzymatic hydrolysis of microcrystalline cellulose and pretreated wheat straw: a detailed comparison using convenient kinetic analysis

Marked slow-down of soluble sugar production at low degree of substrate conversion limits the space-time yield of enzymatic hydrolysis of ligno-cellulosic materials. A simple set of kinetic descriptors was developed to compare reducing sugar release from pure crystalline cellulose (Avicel) and pretreated wheat straw by Trichoderma reesei cellulase at 50 °C. The focus was on the rate-retarding effect of maximum hydrolysis rate at reaction start (r(max)), limiting hydrolysis rate (r(lim)) at extended reaction time (24h), and substrate conversion, marking the transition between the r(max) and r(lim) kinetic regimes (C(trans)). At apparent saturation of substrate (12.2g cellulose/L) with enzyme, r(max) for pretreated wheat straw (~9.6g/L/h) surpassed that for Avicel by about 1.7-fold whereas their r(lim) were almost identical (~0.15 g/L/h). C(trans) roughly doubled as enzyme/substrate loading was increased from 3.8 to 75FPU/g, suggesting C(trans) to be a complex manifestation of cellulase-cellulose interaction, not an intrinsic substrate property. A low-temperature adsorption step preceding hydrolysis at 50 °C resulted in enhanced cellulase binding at reaction start without increasing r(max). C(trans) was higher for pretreated wheat straw (~30%) than for Avicel (~20%) under these conditions.

Cerebral venous thrombosis: diagnostic accuracy of combined, dynamic and static, contrast-enhanced 4D MR venography

BACKGROUND AND PURPOSE

MR including MRV is an established method to diagnose CVT. However, it remains unsettled which MR imaging modalities offer the highest diagnostic accuracy. We evaluated the accuracy of a combined, dynamic (1.5 seconds per dataset) and static (voxel size, 1.1 x 0.9 x 1.5 mm), contrast-enhanced MRV method (combo-4D MRV) relative to other established MR/MRV modalities.

MATERIALS AND METHODS

A total of 39 patients with CVT (n = 20) and control subjects (n = 19) underwent combo-4D MRV, 2D TOF MRV, GRE imaging, and T2W imaging. For these modalities, diagnostic accuracy (ROCs) for CVT affecting 53 out of 234 predefined venous segments was determined. Sensitivity and specificity were separately calculated for different stages of CVT (acute/subacute/chronic).

RESULTS

Combo-4D MRV showed the highest accuracy (AUC, 0.99 [95% CI, 0.97-1.0]; sensitivity, 97% [84%-100%]) for thrombosed dural sinuses. For all thrombosed segments including cortical veins, its sensitivity was best (76% [64%-84%]; AUC, 0.92 [0.88-0.96]), followed by TOF MRV (72% [59%-81%]; AUC, 0.93 [0.88-0.97]). Even for chronic CVT, it showed a relatively high sensitivity of 67% (30%-90%). For thrombosed cortical veins alone, GRE images achieved the highest sensitivity (66% [46%-81%]; AUC, 0.88 [0.78-0.97]). Specificities of all modalities ranged from 96% to 99%.

CONCLUSIONS

Combo-4D MRV showed an excellent accuracy for the diagnosis of dural sinus thrombosis. The analysis of dynamic patterns of contrast enhancement in dural sinuses appeared useful to identify chronic thrombosis. To diagnose thrombosed cortical veins, GRE images should primarily be analyzed.

An efficient plasmid vector for expression cloning of large numbers of PCR fragments in Escherichia coli

The described plasmid pEamTA was designed for parallel polymerase chain reaction (PCR) cloning of open reading frames (ORFs) in Escherichia coli. It relies on the well-known TA-cloning principle, and the "T-vector" can be generated from a plasmid preparation by digestion with the restriction enzyme Eam1105I. The single 3'-T-overhangs of the vector fragment are positioned in a way that A-tailed PCR-products beginning with the start-ATG of an ORF end up in optimal position for expression from a strong tac-promoter when ligated in correct orientation. The orientation of the insert can be checked via a reconstituted NdeI site (catATG) present in correct clones. The protocol works regardless of internal restriction sites of the PCR fragment, a major advantage when cloning a number of fragments in parallel. It also does not require 5'-primer extensions and finally delivers an expression clone for the preparation of untagged protein in less than a week.

Nitrile hydrolysis activity ofRhodococcus erythropolis NCIMB 11540 whole cells

The nitrile hydrolyzing properties of the bacterium strain Rhodococcus erythropolis NCIMB 11540 have been investigated. Using whole cells of the microorganism, a wide variety of aromatic and aliphatic cyanide-containing substrates was successfully hydrolyzed to the corresponding amide or acid. In the case of dicyanides, selective monohydrolysis took place, which was further explored in the desymmetrization of malononitriles resulting in the corresponding cyano amides in enantiomeric excesses of up to 98%.