Dataset Information

Exhaled air dispersion during noninvasive ventilation via helmets and a total facemask.

ABSTRACT: BACKGROUND:Noninvasive ventilation (NIV) via helmet or total facemask is an option for managing patients with respiratory infections in respiratory failure. However, the risk of nosocomial infection is unknown. METHODS:We examined exhaled air dispersion during NIV using a human patient simulator reclined at 45° in a negative pressure room with 12 air changes/h by two different helmets via a ventilator and a total facemask via a bilevel positive airway pressure device. Exhaled air was marked by intrapulmonary smoke particles, illuminated by laser light sheet, and captured by a video camera for data analysis. Significant exposure was defined as where there was ? 20% of normalized smoke concentration. RESULTS:During NIV via a helmet with the simulator programmed in mild lung injury, exhaled air leaked through the neck-helmet interface with a radial distance of 150 to 230 mm when inspiratory positive airway pressure was increased from 12 to 20 cm H2O, respectively, while keeping the expiratory pressure at 10 cm H2O. During NIV via a helmet with air cushion around the neck, there was negligible air leakage. During NIV via a total facemask for mild lung injury, air leaked through the exhalation port to 618 and 812 mm when inspiratory pressure was increased from 10 to 18 cm H2O, respectively, with the expiratory pressure at 5 cm H2O. CONCLUSIONS:A helmet with a good seal around the neck is needed to prevent nosocomial infection during NIV for patients with respiratory infections.

SUBMITTER: Hui DS

PROVIDER: S-EPMC7094250 | biostudies-literature | 2015 May

REPOSITORIES: biostudies-literature

ACCESS DATA

Publications

Exhaled air dispersion during noninvasive ventilation via helmets and a total facemask.

Hui David S DS Chow Benny K BK Lo Thomas T Ng Susanna S SS Ko Fanny W FW Gin Tony T Chan Matthew T V MTV

Chest 20150501 5

<h4>Background</h4>Noninvasive ventilation (NIV) via helmet or total facemask is an option for managing patients with respiratory infections in respiratory failure. However, the risk of nosocomial infection is unknown.<h4>Methods</h4>We examined exhaled air dispersion during NIV using a human patient simulator reclined at 45° in a negative pressure room with 12 air changes/h by two different helmets via a ventilator and a total facemask via a bilevel positive airway pressure device. Exhaled air ...[more]

PMID: 25392954

Similar Datasets

Project description:Current facemask research focuses on material characterization and efficiency; however, facemasks are often not tested such that aerosol distributions are evaluated from the gaps in the sides, bottom, and nose areas. Poor evaluation methods could lead to misinformation on optimal facemasks use; a high-throughput, reproducible method which illuminates the issue of fit influencing aerosol transmission is needed. To this end, we have created an in vitro model to quantify particle transmission by mimicking exhalation aerosols in a 3D printed face-nose-mouth replica via a nebulizer and quantifying particle counts using a hand-held particle counter. A sewn, sewn with pipe cleaner nose piece, and sewn with a coffee filter facemask were used to evaluate current common homemade sewn facemask designs, benchmarked against industry standard surgical, N95 respirator tightly fit, and N95 respirator loosely fit facemasks. All facemasks have significantly reduced particle counts in front of the facemask, but the side and top of the facemask showed increases in particle counts over the no facemask condition at that same position, suggesting that some proportion of aerosols are being redirected to these gaps. An altered size distribution of aerosols that escape at the vulnerable positions was observed; escaped particles have larger count median diameters, with a decreased ratio of smaller to larger particles, possibly due to hygroscopic growth or aggregation. Of the homemade sewn facemasks, the facemask with a coffee filter insert performed the best at reducing escaped aerosols, with increased efficiency also observed for sewn masks with a pipe cleaner nose piece. Importantly, there were minimal differences between facemasks at increasing distances, which supports that social distance is a critical element in reducing aerosol transmission. This work brings to light the importance of quantifying particle count in positions other than directly in front of the facemask and identifies areas of research to be explored.

Project description:ObjectivesMany survivors of acute respiratory distress syndrome have poor long-term outcomes possibly due to supportive care practices during "invasive" mechanical ventilation. Helmet noninvasive ventilation in acute respiratory distress syndrome may reduce intubation rates; however, it is unknown if avoiding intubation with helmet noninvasive ventilation alters the consequences of surviving acute respiratory distress syndrome.DesignLong-term follow-up data from a previously published randomized controlled trial.PatientsAdults patients with acute respiratory distress syndrome enrolled in a previously published clinical trial.SettingAdult ICU.InterventionNone.Measurements and main resultsThe primary outcome was functional independence at 1 year after hospital discharge defined as independence in activities of daily living and ambulation. At 1 year, patients were surveyed to assess for functional independence, survival, and number of institution-free days, defined as days alive spent living at home. The presence of ICU-acquired weakness and functional independence was also assessed by a blinded therapist on hospital discharge. On hospital discharge, there was a greater prevalence of ICU-acquired weakness (79.5% vs 38.6%; p = 0.0002) and less functional independence (15.4% vs 50%; p = 0.001) in the facemask group. One-year follow-up data were collected for 81 of 83 patients (97.6%). One-year mortality was higher in the facemask group (69.2% vs 43.2%; p = 0.017). At 1 year, patients in the helmet group were more likely to be functionally independent (40.9% vs 15.4%; p = 0.015) and had more institution-free days (median, 268.5 [0-354] vs 0 [0-323]; p = 0.017).ConclusionsPoor functional recovery after invasive mechanical ventilation for acute respiratory distress syndrome is common. Helmet noninvasive ventilation may be the first intervention that mitigates the long-term complications that plague survivors of acute respiratory distress syndrome managed with noninvasive ventilation.

Project description:BackgroundTransmission of viral diseases (e.g., influenza A H1N1) via respiratory droplets takes place mainly in confined spaces, including in aircraft during commercial air travel. The adoption of hygiene measures may help to prevent disease spread aboard aircraft. This review summarizes the evidence on hand hygiene and the use of facemasks as viral disease prevention measures in aircraft.MethodsA literature search was performed in the PubMed, Scopus, and Web of Science databases up to 10 June 2020, according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses criteria. A population, intervention, comparison, outcomes, and study design (PICOS) approach was used to define the review question.ResultsWe included four studies published between 2007 and 2020, all targeting influenza virus disease, in the qualitative synthesis. Three studies used mathematical models to simulate single- or multiple-direction flights, and two of them showed that facemask (e.g., N95 respirator) use considerably reduced infection probability. In the third study, hand cleaning by 20 to 60% of people at any time in all airports (including on aircraft) reduced the measure of airports' power to spread the disease across the globe by ~ 24 to 69%. The fourth study was a case-control study designed to trace an influenza outbreak in two flights during the 2009 influenza A H1N1 pandemic. The study showed that none (0%) of nine infected passengers compared to 15 (47%) of 32 healthy control passengers in the aircraft cabin during one of these flights wore a facemask (odds ratio, 0.0; 95% confidence interval, 0.0-0.7). In contrast, both case and control passengers appeared to be equally compliant in self-assessed hand hygiene.ConclusionsFacemask use combined with hand hygiene may minimize the chance of droplet-transmitted virus spread by air travelers. Thus, it is necessary that hygiene measures become an integral part of standard procedures in commercial air travel.

Dataset Information

Exhaled air dispersion during noninvasive ventilation via helmets and a total facemask.

Publications

Exhaled air dispersion during noninvasive ventilation via helmets and a total facemask.

Similar Datasets

OmicsDI is part of the ELIXIR infrastructure

Tweets