Nasal High Flow via a Single, Sealed Nostril in Patients with Respiratory Failure

The study purpose is to test the delivery of Nasal High Flow (NHF) therapy via a single, sealed nostril in adult patients with respiratory failure who are receiving NHF therapy as their standard care in the intensive care unit (ICU) or high dependency unit (HDU). The therapy will be applied by trained hospital staff. The NHF therapy will be delivered via the single, sealed nostril for up-to one-hour in patients who were already receiving NHF therapy via a two-prong interface (i.e. comparator) as their standard care. Before and after using the investigative interface the participant will receive the NHF therapy via the comparator interface. Despite a brief transition time during the exchange of interfaces, there will be no period of time when the patient is not receiving NHF therapy during the study. The primary end-point will be ventilation parameters at ne-hour following the application of the investigative interface for one-hour. The study is a prospective, cross-over design. The study will last for two and a half (2.5) hours. The settings of the NHF while the investigative interface is being applied will be adjusted to match the same patient ventilation parameters as recorded during the use of NHF therapy delivered via the comparator interface. Therefore, the settings of the NHF (flow rate, FiO2) will be adjusted according to each patient. At any time during the study, the patient can request to have the investigative interface removed and replaced by the comparator interface. The patient will be constantly monitored during the study using standard practice and at any time during the study the medical and nursing staff can decide to change therapies if they deem that it is in the best interest of the patient.