RESUMO
AIMS: Assess the feasibility of using light from artificial sun lamps to decontaminate N95 filtering facepiece respirators (FFRs) contaminated with SARS-CoV-2. METHODS AND RESULTS: FFR coupons or whole FFRs contaminated with 5 log10 TCID50 (target concentration) SARS-CoV-2 in culture media, simulated saliva, or simulated lung fluid were dried for 1-2 h, then exposed to light from tanning and horticulture lamps to assess decontamination. Exposed coupons and whole FFRs showed SARS-CoV-2 inactivation for all matrices tested. Furthermore, FFRs still met performance specifications after five decontamination cycles. CONCLUSIONS: It is feasible that artificial sunlight from these sun lamps can be used to decontaminate FFRs provided the UV dose is sufficient and the light is unobstructed. Furthermore, decontamination can be performed up to five times without degrading FFR performance. SIGNIFICANCE AND IMPACT OF THE STUDY: This research shows a proof of principle that artificial sun lamps may be an option to decontaminate SARS-CoV-2 on N95 FFRs. UV doses required for inactivation to levels below detection ranged from 4 to 37·8 J cm-2 depending on the light source, virus matrix and FFR type.
Assuntos
COVID-19 , Reutilização de Equipamento , Descontaminação , Humanos , Respiradores N95 , SARS-CoV-2RESUMO
Decontamination of N95 filtering facepiece respirators (FFRs) is a crisis capacity strategy allowed when there are known shortages of FFRs. The application of moist heat is one decontamination method that has shown promise and is the approach approved in the Steris Steam Emergency Use Authorization (EUA). This effort examines the use of multicookers to apply moist heat, as they are available in retail stores and more affordable than methods requiring more sophisticated equipment. Four of five multicooker models examined met the acceptance criteria for the test and one model was selected for inactivation testing. Tests were performed on four different FFR models with SARS-CoV-2 suspended in culture media, simulated saliva or simulated lung fluid. Moist heat treatment reduced recoverable titres of SARS-CoV-2 virus to levels below the limit of detection in all tests. Furthermore, these four FFR models showed no loss in collection efficiency, inhalation resistance or visual damage after up to 10 decontamination cycles. Two (2) FFR models showed a slight change in strap elasticity (<9%). These data show that moist heat treatment using a multicooker is a viable option for FFR decontamination in a crisis capacity strategy.
Assuntos
COVID-19/prevenção & controle , Descontaminação/métodos , Reutilização de Equipamento , Temperatura Alta , Respiradores N95 , Humanos , SARS-CoV-2/isolamento & purificaçãoRESUMO
Sustained monomorphic ventricular tachycardia (VT) is a paradigm of a stable reentrant rhythm. The hallmark of stable reentry is the presence of an excitable gap, which in reentrant VT composes 15% to 45% of the tachycardia cycle length. Resetting allows definition of the extent and pattern of the excitable gap. Site-specific resetting responses suggest that the VT circuit has both functionally and anatomically derived characteristics. Entrainment provides information regarding the effects of overdrive pacing on properties of the tissue composing the circuit rather than on properties of the tachycardia itself. These data help us to understand the mechanisms of pharmacologic agents and to direct ablation of reentrant VT.
Assuntos
Infarto do Miocárdio/complicações , Infarto do Miocárdio/fisiopatologia , Fibrilação Ventricular/etiologia , Fibrilação Ventricular/fisiopatologia , Animais , Eletrofisiologia , HumanosRESUMO
Ablation of reentrant ventricular tachycardia (VT) is an accepted therapy for certain patients with VT caused by coronary artery disease (CAD). Its use is currently limited to patients with sustained, monomorphic, hemodynamically tolerated VT. The use of entrainment in mapping reentrant VT has made possible increasingly accurate localization of critical sites on the reentrant pathway that are amenable to ablation. Recent work has examined the accuracy with which various mapping criteria are able to predict successful ablation of reentrant VT in patients with CAD. Other recent studies have investigated attempted ablation of all inducible VTs in patients with multiple VT morphologies. In the future, substrate mapping may make possible ablation of VT in patients with nonsustained or fast, hemodynamically unstable VTs, thus allowing VT ablation to become a first-line therapy for many patients with VT in the setting of CAD.