Ferioli M, Cisternino C, Leo V, Pisani L, Palange P, Nava S. Eur Respir Rev. 2020 Apr 3;29(155):200068
The objective of this paper is to provide evidence-based recommendations for the correct use of respiratory devices in the COVID-19 emergency and protect healthcare workers from contracting the SARS-CoV-2 infection. Current evidence shows that around 20% of COVID-19 patients develop a severe Respiratory Distress Syndrome, which in almost a third of the cases requires respiratory support treatment. This type of support includes the use of oxygen therapy, HFNC, CPAP and NIV, which are non-invasive methods with a high risk of aerosol dispersion, especially in unprotected environments. Amongst those methods of delivery of non-invasive respiratory support, the use of a respiratory helmet with an inflatable neck cushion represents the safest option. In addition, data suggest that respecting the indications for the use of PPE is effective in preventing infections among healthcare workers, as demonstrated in a case–control study conducted during the SARS epidemic in Hong Kong. This study investigated the effective adhesion of personnel to PPE (gloves, disposable shirts, goggles and masks) and reported that none of the staff using all the safety measures contracted the virus, while all the infected staff had omitted at least one of them. Therefore, the helmet with neck cushion to treat infected patients with severe respiratory distress syndrome and PPE measures by the personnel must be adopted to prevent the spreading of infection amongst other patients and medical personnel.
Link to abstract.
Hui DS, Chow BK, Lo T, Ng SS, Ko FW, Gin T, Chan MTV. Chest. 2015 May;147(5):1336-1343.
This study set out to determine the extent of exhaled air dispersion, which is linked to the rate of nosocomial infections, when employing NIV using a high-fidelity human patient simulator. Two different helmets and one face mask were put to the test, which included the Sea-Long Medical Systems helmet, the StarMed CaStar R helmet and a Koninklijke Philips total facemask. Exhaled air was evaluated 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 labelled by intrapulmonary smoke particles, illuminated by laser light sheet, and captured through a camera for data analysis. Results have demonstrated that during NIV via the Sea-Long Medical Systems helmet, exhaled air leaked through the neck seal reaching a radial distance of 150 to 230 mm. The patient simulator was programmed for mild lung injury and treated with inspiratory positive airway pressure from 12 to 20cm/H2O respectively and with expiratory pressure of 10cm/H2O. However, when delivering NIV via a StarMed CaStar R helmet with air cushion around the neck, air leakage was negligible. On the other hand, when administering NIV via a total face mask, air leaked through the exhalation port to a distance of 618 and 812 mm when inspiratory pressure was increased from 10 to 18 cm H2O, with the expiratory pressure at 5cm H2O. Therefore, using the helmet with a good seal around the neck represents the best option to prevent nosocomial infection during NIV for patients with respiratory infections.
Link to abstract.