Exhaled air dispersion and removal is influenced by isolation room size and ventilation settings during oxygen delivery via nasal cannula

AbstractThe COVID-19 pandemic has caused huge impact on public health and significantly changed our lifestyle. This is due to the fast airborne oro-nasal transmission of SARS-CoV-2 from the infected individuals. The generation of liquid aerosolized particles occurs when the COVID-19 patients speak, sing, cough, sneeze, or simply breathe. We have developed a novel aerosol barrier mask (ABM) to mitigate the spread of SARS-CoV-2 and other infectious pathogens. This Aerosol Barrier Mask is designed for preventing SARS-CoV-2 transmission while transporting patients within hospital facilities. This mask can constrain aerosol and droplet particles and trap them in a biofilter, while the patient is normally breathing and administrated with medical oxygen. The system can be characterized as an oxygen delivery and mitigation mask which has no unfiltered exhaled air dispersion. The mask helps to prevent the spread of SARS-CoV-2, and potentially other infectious respiratory pathogens and protects everyone in general, especially healthcare professionals.

Download Full-text

Exhaled air dispersion during high-flow nasal cannula therapy versus CPAP via different masks

European Respiratory Journal ◽

10.1183/13993003.02339-2018 ◽

2019 ◽

Vol 53 (4) ◽

pp. 1802339 ◽

Cited By ~ 113

Author(s):

David S. Hui ◽

Benny K. Chow ◽

Thomas Lo ◽

Owen T.Y. Tsang ◽

Fanny W. Ko ◽

...

Keyword(s):

Sagittal Plane ◽

High Flow ◽

Nasal Cannula ◽

Normal Lung ◽

High Flow Nasal Cannula ◽

Air Concentration ◽

Human Patient ◽

Air Dispersion ◽

Exhaled Air ◽

Oronasal Mask

BackgroundHigh-flow nasal cannula (HFNC) is an emerging therapy for respiratory failure but the extent of exhaled air dispersion during treatment is unknown. We examined exhaled air dispersion during HFNC therapy versus continuous positive airway pressure (CPAP) on a human patient simulator (HPS) in an isolation room with 16 air changes·h−1.MethodsThe HPS was programmed to represent different severity of lung injury. CPAP was delivered at 5–20 cmH2O via nasal pillows (Respironics Nuance Pro Gel or ResMed Swift FX) or an oronasal mask (ResMed Quattro Air). HFNC, humidified to 37°C, was delivered at 10–60 L·min−1 to the HPS. Exhaled airflow was marked with intrapulmonary smoke for visualisation and revealed by laser light-sheet. Normalised exhaled air concentration was estimated from the light scattered by the smoke particles. Significant exposure was defined when there was ≥20% normalised smoke concentration.ResultsIn the normal lung condition, mean±sd exhaled air dispersion, along the sagittal plane, increased from 186±34 to 264±27 mm and from 207±11 to 332±34 mm when CPAP was increased from 5 to 20 cmH2O via Respironics and ResMed nasal pillows, respectively. Leakage from the oronasal mask was negligible. Mean±sd exhaled air distances increased from 65±15 to 172±33 mm when HFNC was increased from 10 to 60 L·min−1. Air leakage to 620 mm occurred laterally when HFNC and the interface tube became loose.ConclusionExhaled air dispersion during HFNC and CPAP via different interfaces is limited provided there is good mask interface fitting.

Download Full-text

Randomised controlled trial to assess the effectiveness of apnoeic oxygenation in adults using low-flow or high-flow nasal cannula with head side elevation versus usual care to prevent desaturation during endotracheal intubation in the emergency department (ApOxED): study protocol

BMJ Open ◽

10.1136/bmjopen-2020-037964 ◽

2020 ◽

Vol 10 (11) ◽

pp. e037964

Author(s):

Shahan Waheed ◽

Nazir Najeeb Kapadia ◽

Muhammad Faisal Khan ◽

Salima Mansoor Kerai ◽

Ahmed Raheem ◽

...

Keyword(s):

Endotracheal Intubation ◽

Direct Laryngoscopy ◽

Oxygen Delivery ◽

High Flow ◽

Nasal Cannula ◽

Low Flow ◽

Usual Practice ◽

High Flow Oxygen ◽

Randomised Controlled ◽

Apnoeic Oxygenation

IntroductionApnoeic oxygenation is a process of delivering continuous oxygen through nasal cannula during direct laryngoscopy. The oxygen that is delivered through these nasal cannulas is either low flow or high flow. Although the effectiveness of apnoeic oxygenation has been shown through systematic reviews and randomised controlled trials, a comparison of high-flow versus low-flow oxygen delivery has not been tested through a superiority study design. In this study we propose to assess the effectiveness of giving low-flow oxygen with head side elevation versus high-flow oxygen with head side elevation against the usual practice of care in which no oxygen is provided during direct laryngoscopy.Methods and analysisThis will be a three-arm study instituting a block randomisation technique with a sample size of 46 in each arm (see table 1). Due to the nature of the intervention, no blinding will be introduced. The primary outcomes will be lowest non-invasive oxygen saturation measurement during direct laryngoscopy and during the 2 min after the placement of the tube and the first pass success rate. The intervention constitutes head side elevation up to 30° for improving glottis visualisation together with low-flow or high-flow oxygen delivery through nasal cannula to increase safe apnoea time for participants undergoing endotracheal intubation. Primary analysis will be intention to treat.Ethics and disseminationThe study is approved by the Ethical Review Committee of Aga Khan University Hospital (2019-0726-2463). The project is an institution University Research Committee grant recipient 192 002ER-PK. The results of the study will be disseminated among participants, patient communities and healthcare professionals in the institution through seminars, presentations and emails. Further, the findings will be published in a highly accessed peer-reviewed medical journal and will be presented at both national and international conferences.Trial registration numberClinicalTrials.gov Registry (NCT04242537).

Download Full-text