Association of dead space fraction to mortality in patients with COVID-19-related ARDS: A historical cohort observational study.

OBJECTIVE: To assess the correlation of dead space fraction (VD/VT) measured through time capnography, corrected minute volume (CMV) and ventilation ratio (VR) with clinical outcomes in COVID-19 patients requiring invasive mechanical ventilation. DESIGN: Observational study of a historical cohort. SETTING: University hospital in Medellin, Colombia. PARTICIPANTS: Patients aged 15 and above with a confirmed COVID-19 diagnosis admitted to the ICU and requiring mechanical ventilation. INTERVENTIONS: Measurement of VD/VT, CMV, and VR in COVID-19 patients. MAIN VARIABLES OF INTEREST: VD/VT, CMV, VR, demographic data, oxygenation indices and ventilatory parameters. RESULTS: During the study period, 1047 COVID-19 patients on mechanical ventilation were analyzed, of whom 446 (42%) died. Deceased patients exhibited a higher prevalence of advanced age and obesity, elevated Charlson index, higher APACHE II and SOFA scores, as well as an increase in VD/VT ratio (0.27 in survivors and 0.31 in deceased) and minute ventilation volume on the first day of mechanical ventilation. The multivariate analysis revealed independent associations to in-hospital mortality, higher VD/VT (HR 1.24; 95%CI 1.003-1.525; p = 0.046), age (HR 1.024; 95%CI 1.014-1.034; p < 0.001), and SOFA score at onset (HR: 1.036; 95%CI: 1.001-1.07; p = 0.017). CONCLUSIONS: VD/VT demonstrated an association with mortality in COVID-19 patients with ARDS on mechanical ventilation. These findings suggest that VD/VT measurement may serve as a severity marker for the disease.

Meta-analysis of incidence and outcomes of life-threatening arrhythmias in takotsubo cardiomyopathy.

BACKGROUND: Takotsubo cardiomyopathy (TC) or stress-induced cardiomyopathy is a transient heart condition that clinically resembles an acute coronary syndrome. This study aims to assess the incidence of life-threatening arrhythmias in patients with Takotsubo cardiomyopathy and evaluate the outcomes of patients with life-threatening arrhythmias (LTAs) in Takotsubo cardiomyopathy compared with those without LTA. METHODS: We comprehensively searched the PubMed, Google Scholar, and Embase databases from inception to February 2021. The primary aim of the study was to determine the incidence of LTAs in TC patients. Other outcomes of interest were the odds of in-hospital, long-term mortality, and cardiogenic shock (CS) in TC patients with LTAs versus those without LTAs. For all statistical analyses, ReviewManager and MedCalc were used. RESULTS: Eighteen studies were included in this study involving 55,557 participants (2,185 with LTAs and 53,372 without LTAs). The pooled incidence of LTAs in the patients of TC was found to be 6.29% (CI: 4.70-8.08%; I2 = 94.67%). There was a statistically significant increased risk of in-hospital mortality (OR = 4.74; CI: 2.24-10.04; I2 = 77%, p < 0.0001) and cardiogenic shock (OR = 5.60; CI: 3.51-8.95; I2 = 0%, p < 0.00001) in the LTA group versus the non-LTA group. LTA was not associated with long-term mortality (OR = 2.23; CI: 0.94-5.28; I2 = 53%, p = 0.07). CONCLUSION: The pooled incidence of life-threatening arrhythmias in the patients of TC was found to be 6.29%. In the group of TC patients with LTAs, the odds of in-hospital mortality and CS, was higher than in the TC patients without LTAs.

Numerical modeling of bare and polymer-covered braided stents using torsional and tensile springs connectors.

Computational modeling of braided stents using the finite element (FE) method has become an essential tool in the design and development of these medical devices. One of the most challenging issues in such a task is representing in an accurate manner the interaction between the interlacing wires. With the goal of achieving a compromise between accuracy and computational affordability, we propose a new approach consisting in using 1D FE formulations equipped with torsional springs at the crossover points of the wires. In the case of covered braided stents, the model is enriched with a set of tensile springs (defined in the longitudinal direction), aimed at capturing the stiffening effect of the polymeric membrane. The predictive capabilities of the proposed model are evaluated using data of our own experimental tests, as well as data from other tests in the literature. The simulations demonstrate that the proposed model is able to predict the (markedly nonlinear) behavior of stents when subjected to radial and axial cycle loads, with errors at the end of the compression stage ranging from 0.5% to 10% in all cases.

Suction force rather than aspiration flow correlates with recanalization in hard clots: an in vitro study model.

BACKGROUND: ANA Advanced Neurovascular Access provides a novel funnel component designed to reduce clot fragmentation and facilitate retrieval in combination with stent-retrievers (SRs) in stroke patients by restricting flow and limiting clot shaving. In previous publications ANA presented excellent in vitro/in vivo efficacy data, especially with fibrin-rich hard clots. We aimed to determine the main physical property responsible for these results, namely suction force versus aspiration flow. METHODS: We evaluated in a bench model the suction force and flow generated by ANA and compared them to other neurovascular catheters combined with a SR (Solitaire). Aspiration flow was evaluated with a flow rate sensor while applying vacuum pressure with a pump. Suction force was determined using a tensile strength testing machine and a purposely designed tool that completely seals the device tip simulating complete occlusion by a hard clot. Suction force was defined as the force needed to separate the device from the clot under aspiration. All experiments were repeated five times, and mean values used for comparisons. RESULTS: Aspiration flow increased with the inner diameter of the device: ANA 1.85±0.04 mL/s, ACE68 3.74±0.05 mL/s, and 8F-Flowgate2 5.96±0.30 mL/s (P<0.001). After introducing the SR, the flow was reduced by an average of 0.57±0.12 mL/s. Due to its larger distal surface, ANA suction force (1.69±0.40 N) was significantly higher than ACE68 (0.26±0.04 N) and 8F-Flowgate2 (0.42±0.06 N) (P<0.001). After introducing the SR, suction force variation was not relevant except for ANA that increased to 2.64±0.41 N. CONCLUSION: Despite lower in vitro aspiration flow, the ANA design showed a substantially higher suction force than other thrombectomy devices.

19p13.3 Deletion With Polyotia: A Case Report and Literature Review.

Mutations at chromosome 19 are rare, and reports in the literature are scarce and clinically variable. This chromosome has a high genetic density, and hence a given deletion can cause distinctive effects on body systems and, in addition, result in a characteristic phenotype.  We report the case of a patient who presented with distinctive signs and symptoms such as delayed psychomotor development, severe postnatal delay, dolichocephaly, polyotia, and ocular hypertelorism. Even though all cases with a chromosome 19 deletion do not present in the same way, they still share some clinical manifestations that should be considered, which prompted us to present a summary of the available literature on the subject. Additionally, to our knowledge, this is the first and only case with polyotia in its phenotype to be reported in Colombia to date.