Saw marks in bone: A preliminary empirical study to inform decision making and best practice.

Forensic toolmark examiners compare marks between those observed on an item/surface and those made by a reference implement, such as a particular tool or weapon, to provide an opinion of the likelihood of common origin. It is widely accepted that such comparison opinions need to be underpinned by empirical research, and this study aimed to add to the knowledge base relied upon when developing and comparing saw marks in bone, a substrate encountered in body dismemberment cases. Porcine bones were used as a human proxy; they were either fresh with residual soft tissue and bodily fluids present ('wet') to replicate dismembered bones shortly post-mortem, or processed to remove soft tissue and moisture content ('dry') to represent cases of dismemberment after an extended period of decomposition and exposure. The bones were cut using one implement of each of five classes: hand saw, mitre saw, reciprocating saw, oscillating saw, and serrated knife. They were cut, either completely through (except for serrated knife), giving two surfaces per cut to examine, or to a depth up to 3 mm (false starts). Five replicates per combination of bone condition, saw, and cut type gave 130 bone samples. These were then cleaned and cast using Isomark Silicone Polymer Compound or Mikrosil, giving 260 cast samples. All bone and cast samples were photographed, examined for various class characteristic markers, and specific markers measured. No significant differences between Isomark and Mikrosil casts were observed when compared side-by-side, demonstrating suitability of both materials for casting of saw marks on bone. Although saw marks presented more class characteristic markers on dry than wet bones, calculations of tooth distances and measurements of kerf width (KW) from marks did not significantly differ between bone conditions, with exception of the reciprocating saw that produced false start marks with significantly larger minimum KW on wet than dry samples. Further analysis supported that tooth distances on marks made by hand and oscillating saws are sufficiently accurate for the determination of saw teeth per inch (TPI). However, one tooth distance on marks made by reciprocating saws did not accurately represent TPI. Finally, examination of presence or absence of class characteristic markers on each saw mark demonstrated consistent variation between saw classes. These results enabled the development of exclusion-based decision trees, and a reference database (available on request), for use by toolmark examiners in their evaluation of saw types based on class characteristic markers observed in cut bone.

Evaluation of Cangrelor Use After Percutaneous Coronary Intervention in Patients With Mechanical Circulatory Support.

OBJECTIVES: To describe cangrelor use in patients on concurrent mechanical circulatory support who underwent postpercutaneous coronary intervention. DESIGN: A single-center, retrospective, cohort study. SETTING: At a quaternary teaching hospital. PARTICIPANTS: Included patients were ≥18 years old, admitted to the intensive care unit, underwent percutaneous coronary intervention with stent placement, initiated on mechanical circulatory support, and received cangrelor in the postpercutaneous coronary intervention period. INTERVENTIONS: Retrospectively analyzed cangrelor use in patients on mechanical circulatory support. MEASUREMENTS AND MAIN RESULTS: The primary outcome was the incidence of thrombosis and bleeding events during cangrelor administration. Additional outcomes included initial cangrelor dose, number of cangrelor dose adjustments per patient, survival from mechanical circulatory support, and mortality within 30 days. Overall, 19 patients were included in this study. In total, 14 patients (74%) experienced a bleeding event; however, 93% were classified as a minor bleed. There was 1 major bleeding event. There were no thrombotic events observed during cangrelor administration. The median initial cangrelor dose was 0.5 µg/kg/min. There were 10 patients who underwent dose adjustment, with the majority being dose reductions based on antiplatelet monitoring (VerifyNow assay). Survival from mechanical circulatory support occurred in 17 patients (89%), and 30-day mortality occurred in 8 patients (42%). CONCLUSIONS: For patients receiving cangrelor as a bridge to oral P2Y12 inhibitor therapy on mechanical circulatory support, the authors observed a low rate of major bleeding and no episodes of thrombosis. Lower starting doses appear feasible with no observed increased risk of thrombotic complications. Future studies are needed to confirm these observations.

Angiotensin II in Patients With Shock on Mechanical Circulatory Support: A Single-Center Retrospective Case Series.

OBJECTIVES: To describe angiotensin II (ANGII) use in patients on mechanical circulatory support (MCS). To evaluate the efficacy and safety of ANGII in patients with shock on MCS. DESIGN: Retrospective cohort study. SETTING: A single-center, quaternary care academic medical center. PARTICIPANTS: The study comprised critically ill patients on MCS. INTERVENTIONS: None. MEASUREMENTS AND MAIN RESULTS: Fourteen patients were included in this retrospective analysis. The median age was 54 years (44.8, 68.3) and 78.6% were men. Six patients were receiving venoarterial extracorporeal membrane oxygenation support, 4 patients were receiving venovenous extracorporeal membrane oxygenation support, and 4 patients were on left ventricular assist devices. Five patients (36%) achieved hemodynamic response to ANGII at 3 hours, defined as a mean arterial pressure (MAP) of ≥65 mmHg or a 10-mmHg increase in MAP with a decrease or no change in total vasopressor dose. Overall, the median MAP increased from 61 mmHg (51, 73) at baseline to 66 mmHg (58, 71) at 3 hours, and the median norepinephrine dose decreased from 0.45 µg/kg/min (0.28, 0.6) at baseline to 0.2 µg/kg/min (0.18, 0.32) at 3 hours. The in-hospital mortality rate was 78.6%. Two patients experienced severe adverse drug events and 1 patient had a sentinel thrombotic event. CONCLUSIONS: This study suggested that ANGII may provide a salvage treatment option in patients on MCS with refractory vasodilatory shock. There are several safety considerations with the use of ANGII in these patients. Prospective randomized controlled trials are needed to evaluate the safety and efficacy of ANGII in patients on MCS.

Evaluation of Continuous Inhaled Epoprostenol in the Treatment of Acute Respiratory Distress Syndrome, Including Patients With SARS-CoV-2 Infection.

BACKGROUND: Acute respiratory distress syndrome (ARDS) management is primarily supportive. Pulmonary vasodilators, such as inhaled epoprostenol (iEPO), have been shown to improve PaO2:FiO2 (PF) and are used as adjunctive therapy. OBJECTIVE: To identify the positive response rate and variables associated with response to iEPO in adults with ARDS. A positive response to iEPO was defined as a 10% improvement in PF within 6 hours. METHODS: This retrospective study included adults with ARDS treated with iEPO. The primary endpoint was the variables associated with a positive response to iEPO. Secondary endpoints were positive response rate and the change in PF and SpO2:FiO2 within 6 hours. Statistical analysis included multivariable regression. RESULTS: Three hundred thirty-one patients were included. As baseline PF increased, the odds of responding to iEPO decreased (odds ratio [OR], 0.752, 95% CI, 0.69-0.819, p < 0.001). Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2)-related ARDS (OR 0.478, 95% CI, 0.281-0.814, p = 0.007) was associated with decreased odds of a positive response to iEPO. The total population had a 68.3% positive response rate to iEPO. SARS-CoV-2-related ARDS and non-SARS-CoV-2-related ARDS had a 59.5% and 72.7% positive response rate, respectively. iEPO significantly improved PF (71 vs 95, P < 0.001) in the whole population. CONCLUSION AND RELEVANCE: iEPO was associated with a positive effect in a majority of moderate-to-severe ARDS patients, including patients with SARS-CoV-2-related ARDS. Lower baseline PF and non-SARS-CoV-2-related ARDS were significantly associated with a positive response to iEPO. The ability to predict which patients will respond to iEPO can facilitate better utilization.