Control de la fuente respiratoria mediante el uso de una mascarilla quirúrgica: un estudio in vitro.

RESUMENLa etiqueta para la tos y la higiene respiratoria son formas de control de la fuente de emisión cuyo uso se alienta para evitar la propagación de infecciones respiratorias. El uso de mascarillas quirúrgicas como medio de control de la fuente en términos de reducción de la exposición de terceros no se ha investigado. En este estudio diseñamos un modelo in vitro utilizando varias mascarillas faciales con el fin de evaluar su aporte a la reducción de la exposición cuando son utilizadas en la fuente infecciosa (Fuente) en comparación con la reducción proporcionada por las mascarillas usadas para la protección primaria (Receptor), así como los factores que contribuyen a cada una. En una cámara con diversos flujos de aire se exhalaron aerosoles radiomarcados desde una cabeza de maniquí de cara blanda ventilada, utilizando respiración periódica y tos (Fuente). En otro maniquí, al que se le colocó un filtro, se cuantificó la exposición del Receptor. Se probaron una mascarilla quirúrgica de ajuste natural, una mascarilla quirúrgica de ajuste seguro (SecureFit) y una mascarilla respiratoria autofiltrante de clase N95 (comúnmente conocida como "mascarilla autofiltrante N95") con y sin sello de vaselina. Con la tos, el control de la fuente (mascarilla quirúrgica/autofiltrante colocada en la Fuente) fue estadísticamente superior a la protección brindada por la mascarilla quirúrgica/mascarilla autofiltrante sin sellar en el Receptor (protección del Receptor) en todos los entornos. Para igualar el control de la fuente durante la tos, la mascarilla autofiltrante N95 debe estar sellada con vaselina. Durante la respiración periódica, el control de la fuente fue comparable o superior a la protección brindada por la mascarilla quirúrgica/autofiltrante en el Receptor. El control de la fuente mediante mascarillas quirúrgicas puede ser una importante defensa adicional contra la propagación de infecciones respiratorias. El ajuste de la mascarilla quirúrgica/autofiltrante combinado con los patrones de flujo de aire en un entorno determinado contribuye de manera significativa a la eficacia del control de la fuente. Los futuros ensayos clínicos deberían incluir un brazo de control de la fuente con mascarilla quirúrgica a fin de evaluar el aporte realizado por el control de la fuente a la protección general contra infecciones de transmisión aérea.

Nutritional Assessment: A Primary Component of the Multidimensional Geriatric Assessment in the Intensive Care Unit.

The importance of evaluating and adjusting the nutritional state of critically ill patients has become a core principle of care. This article focuses on tools for the nutritional assessment of geriatric intensive care unit patients, including a review of imaging and other standardized techniques for evaluation of muscle mass, an indicator of malnutrition and sarcopenia. It concludes with a discussion of the interplay of malnutrition, reduced muscle mass/sarcopenia, and frailty. The goal of this multidimensional assessment is to identify those at risk and thereby initiate interventions to improve outcomes.

Barrier Techniques to Reduce Aerosolization During Extubation.

Preventing exposure of virulent pathogens during aerosolizing procedures such as intubations has been a cause of concern during the coronavirus pandemic. As such, protocols have been adjusted and precautions implemented in order to minimize the risk to the proceduralist. As patients improve, we face another high-risk aerosolizing procedure-extubation. We illustrate a protocol to help minimize the exposure risk during extubation. We describe a barrier technique during extubation which contained aerosolized particulates into a non-rebreather mask at time of extubation. Our protocol allows providers to perform extubations while minimizing exposure to aerosolized particles.

Respiratory source control using a surgical mask: An in vitro study.

Cough etiquette and respiratory hygiene are forms of source control encouraged to prevent the spread of respiratory infection. The use of surgical masks as a means of source control has not been quantified in terms of reducing exposure to others. We designed an in vitro model using various facepieces to assess their contribution to exposure reduction when worn at the infectious source (Source) relative to facepieces worn for primary (Receiver) protection, and the factors that contribute to each. In a chamber with various airflows, radiolabeled aerosols were exhaled via a ventilated soft-face manikin head using tidal breathing and cough (Source). Another manikin, containing a filter, quantified recipient exposure (Receiver). The natural fit surgical mask, fitted (SecureFit) surgical mask and an N95-class filtering facepiece respirator (commonly known as an "N95 respirator") with and without a Vaseline-seal were tested. With cough, source control (mask or respirator on Source) was statistically superior to mask or unsealed respirator protection on the Receiver (Receiver protection) in all environments. To equal source control during coughing, the N95 respirator must be Vaseline-sealed. During tidal breathing, source control was comparable or superior to mask or respirator protection on the Receiver. Source control via surgical masks may be an important adjunct defense against the spread of respiratory infections. The fit of the mask or respirator, in combination with the airflow patterns in a given setting, are significant contributors to source control efficacy. Future clinical trials should include a surgical mask source control arm to assess the contribution of source control in overall protection against airborne infection.

In vitro delivery of aerosolized treprostinil via modern mechanical ventilation.

BACKGROUND: The Tyvaso Inhalation System is a hand-held nebulizer system used to administer treprostinil, an approved therapy for pulmonary arterial hypertension. Our goal was to establish an in vitro method for delivering a standard dose of treprostinil through a ventilator circuit and artificial airway. METHODS: An AeroTech II jet nebulizer (continuous air flow at 10 L/min; Biodex Medical Systems) was placed in the ventilator circuit with a test lung. Two ventilators were tested, the Dräger Evita 2 Dura (Dräger Medical GmbH) and Avea (CareFusion), without humidity. Delivered dose was defined by capturing radiolabeled particles exiting the endotracheal tube with a filter (Pari) and measuring radioactivity. Particle distributions were measured distal to the endotracheal tube by cascade impaction. We hypothesized that drug delivery would be determined by the number of breaths needed, such that the complete time of inspiration totaled 29 sec (e.g., number of breaths needed=29 sec/TI, where TI is the inspiratory time of an average breath read from the ventilator display). RESULTS: Nebulizer output was linear for 6 min, and the standard prescribed target dose of 54 µg (3.1% of full ampule) was delivered in 29 sec. Using our TI algorithm to control delivery, the mean inhaled dose±SD was 72.2±16.5 µg (range 47.2-98.6; n=23). Dräger delivered higher doses than Avea. Effects of mode, breathing pattern, and positive-end expiratory pressures were not significant. The mass median aerodynamic diameter and fine particle fraction were 0.71±0.015 and 0.997±0.0006, respectively. CONCLUSIONS: Using the algorithm, it was possible to deliver aerosolized treprostinil, at controlled doses, via mechanical ventilation over a wide range of controlled breathing patterns. The conditions of nebulization must be precisely followed (one full ampule per treatment, use of the AeroTech II nebulizer, continuous nebulization using an external flow of 10 L/min, bypass of the humidifier or removal of in-line heat and moisture exchanger, and treatment completed in 6 min or less).