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.