Right ventricular free wall longitudinal strain is independently associated with mortality in mechanically ventilated patients with COVID-19.

BACKGROUND: Right ventricular (RV) dysfunction has been commonly reported in patients with Coronavirus disease 2019 (COVID-19), and is associated with mortality in mixed cohorts of patients requiring and not requiring invasive mechanical ventilation (IMV). Using RV-speckle tracking echocardiography (STE) strain analysis, we aimed to identify the prevalence of RV dysfunction (diagnosed by abnormal RV-STE) in patients with COVID-19 that are exclusively undergoing IMV, and assess association between RV dysfunction and 30 day mortality. We performed a prospective multicentre study across 10 ICUs in Scotland from 2/9/20 to 22/3/21. One-hundred-and-four echocardiography scans were obtained from adult patients at a single timepoint between 48 h after intubation, and day 14 of intensive care unit admission. We analysed RV-STE using RV free-wall longitudinal strain (RVFWLS), with an abnormal cutoff of > -20%. We performed survival analysis using Kaplan-Meier, log rank, and multivariate cox-regression (prespecified covariates were age, gender, ethnicity, severity of illness, and time since intubation). RESULTS: Ninety-four/one-hundred-and-four (90.4%) scans had images adequate for RVFWLS. Mean RVFWLS was -23.0% (5.2), 27/94 (28.7%) of patients had abnormal RVFWLS. Univariate analysis with Kaplan-Meier plot and log-rank demonstrated that patients with abnormal RVFWLS have a significant association with 30-day mortality (p = 0.047). Multivariate cox-regression demonstrated that abnormal RVFWLS is independently associated with 30-day mortality (Hazard-Ratio 2.22 [1.14-4.39], p = 0.020). CONCLUSIONS: Abnormal RVFWLS (> -20%) is independently associated with 30-day mortality in patients with COVID-19 undergoing IMV. Strategies to prevent RV dysfunction, and treatment when identified by RVFWLS, may be of therapeutic benefit to these patients. TRIAL REGISTRATION: Retrospectively registered 21st Feb 2021. CLINICALTRIALS: gov Identifier: NCT04764032.

Study protocol for COVID-RV: a multicentre prospective observational cohort study of right ventricular dysfunction in ventilated patients with COVID-19.

INTRODUCTION: COVID-19 can cause severe acute respiratory failure requiring management in intensive care unit with invasive ventilation and a 40% mortality rate. Cardiovascular manifestations are common and studies have shown an increase in right ventricular (RV) dysfunction associated with mortality. These studies, however, comprise heterogeneous patient groups with few requiring invasive ventilation. This study will investigate the prevalence and prognostic significance of RV dysfunction in ventilated patients with COVID-19 which may lead to targeted interventions to improve patient outcomes. METHODS AND ANALYSIS: This prospective multicentre observational cohort study will perform transthoracic echocardiography (TTE) in 150 patients with COVID-19 requiring invasive ventilation for more than 48 hours. RV dysfunction will be defined as TTE evidence of RV dilatation along with the presence of septal flattening. Baseline demographics, disease severity data and clinical information relating to proposed aetiological mechanisms of RV dysfunction (acute respiratory distress syndrome (ARDS), disordered coagulation, direct myocardial injury and ventilation) will be collected and analysed.Primary outcome measures include the prevalence of RV dysfunction and its association with 30-day mortality. Exploratory outcome measures will investigate the association of the proposed aetiological mechanisms of RV dysfunction to the primary outcomes.Prevalence of RV dysfunction will be determined along with 95% Clopper-Pearson CIs and 30-day survival will be analysed using logistic regression adjusting for patient demographics, phase of disease and baseline severity of illness. The role of potential aetiological factors (ARDS, disordered coagulation, direct myocardial injury and ventilation) in relation to the primary outcomes will be analysed using logistic regression. ETHICS AND DISSEMINATION: Approval was gained from Scotland A Research Ethics Committee (REC reference 20/SS/0059). Findings will be disseminated by various methods including webinars, international presentations and publication in peer-reviewed journals.

Evaluating Over-the-Counter Household Insecticide Aerosols for Rapid Vector Control of Pyrethroid-Resistant Aedes aegypti.

Vector control methods that mobilize and impact rapidly during dengue, Zika, and chikungunya outbreaks are urgently needed in urban contexts. We investigated whether one person using a handheld aerosolized insecticide could achieve efficacy levels comparable to targeted indoor residual spraying (TIRS), using pyrethroid-resistant Aedes aegypti in a semi-field setting with experimental houses in Mexico. The insecticide product (H24, a carbamate and pyrethroid mixture), available over-the-counter locally, was sprayed only on known Ae. aegypti-resting surfaces, for example, walls less than 1.5 m and dark hidden areas. In six identical houses with paired bedrooms, one bedroom was treated, and the other remained an untreated control. Each week for 8 weeks, 100 female pyrethroid-resistant Ae. aegypti were released in each bedroom and followed up daily. Mortality rates in treated bedrooms exceeded 90% for at least 2 weeks, and more than 80% (89.2; 95% CI: 79.98-98.35) for 3 weeks or more. Mortality rates in control houses were zero. Results demonstrate that the immediate impact of TIRS can be delivered by one person using existing products, at an estimated cost for the average household in Mexico of under US$3 per month. Triggered by early outbreak signs, dissemination via community hubs and mass/social media of instructions to treat the home immediately, with monthly re-treatment thereafter, provides a simple means to engage and empower householders. Compatible with integrated vector management strategies, it enables self-protection even if existing agencies falter, a situation exemplified by the potential impact on vector control of the restrictions imposed during the 2020 COVID-19 pandemic.