Time spent with oxygen levels within a safe range using the a new oxygen delivery device in automatic or manual mode in adults admitted to hospital (with or without COVID-19)

Participants randomised to the intervention group will have their oxygen delivered by the Airvo-3 acute device using its closed loop oxygen control function. This function is capable of automatically adjusting the delivered oxygen concentration, and titrating it to a pre-specified SpO2 target range (92-96% or 88-92%). The randomised intervention will continue until 9 hours after randomisation. A study investigator will set up the Airvo 3 acute device outside the patient’s room. The device setup will include various inputs to record SpO2, heart rate, FiO2, flow, pressures, temperature, respiratory rate, and device related technical data. This data will be downloaded at the end of the study period. The Airvo 3 acute device will then be set to 1 of its 3 possible respiratory support modes. The choice of respiratory support mode (NHF, CPAP or Bi-Level) and settings for each mode will be prescribed by the treating clinician, with study investigator advice if required. The oxygen saturation target range will be set between either 88-92% or 92-96%. The decision around device setting, and any decisions related to changes in respiratory support mode during the trial will be at the discretion of the treating clinician. The participant’s nurse and study investigator will then enter the patient’s room with the Airvo3 acute device. The device will be attached to the wall oxygen outlet via high pressure tubing. The device will be able to deliver a variable FiO2 within pre-set upper and lower limits, which can be adjusted by the study investigator or participants nurse. The Airvo 3 acute device will be set to automatic oxygen titration mode with a target SpO2 between 92 and 96% or 88 and 92%. A study investigator will set the initial FiO2 to maintain SpO2 within target range. The FiO2 which maintains the participant’s SpO2 at the mid-point of each target range (94% for 92-96% group and 90% for 88-92% group) will be set as the mid-point for the appropriate FiO2 range. For example, if 30% FiO2 was required to maintain an SpO2 of 94% for a participant with a target SpO2 of 92-96%, the FiO2 range 25-35% would be selected. An investigator will remain with the participant for 15 minutes to ensure the treatment is tolerated. The Airvo 3 acute device will display SpO2, FiO2, flow rate or machine pressure settings, and temperature which will be visible to the participant and healthcare professionals. A low SpO2 alarm will be set to 80%. The SpO2 alarm thresholds can be changed at the discretion of a treating clinician. An alarm will sound in the event of poor SpO2 signal quality or loss of SpO2 signal. In the event of a requirement for escalation of FiO2, the device will automatically increase the FiO2 to maintain SpO2 in target range. The FiO2 will only increase to the set upper FiO2 limit. When the device reaches this FiO2 upper limit, an alarm will sound. This will prompt the participants nurse and study investigator to adjust the FiO2 upper and lower limit parameters and/or arrange medical review. Mandatory medical review will occur if the required FiO2 to keep the participant in SpO2 target range exceeds 0.55 for 10 minutes. If the participant deteriorates to the extent that they require transfer to ICU then they will be withdrawn from the study. Until this point is met, participants with FiO2 requirements >0.55 will continue in the study. If a participants required FIO2 increases to >0.60 for at least 10 minutes they will be withdrawn from the study. When mobilising, nursing staff will be instructed to disconnect the wall oxygen and connect an oxygen bottle to the Airvo 3 acute device. Oxygen therapy can be weaned and discontinued during the study period. If oxygen therapy is discontinued, the nasal cannula or NIV mask will be removed from the participant and the Airvo 3 acute device turned off. The patient remains under the care of the admitting medical team throughout the study duration, with a study investigator available for advice if necessary. At this time, the data captured on the Airvo-3 acute device will be downloaded into a secure database, and assessed for adherence to the control treatment. The data of patients who are withdrawn prior to the completion of the 8 hours of the 9-hour trial will be replaced by another participant but will be included in a sensitivity analysis. On reaching 9 hours post randomisation, those who require ongoing oxygen therapy will be transferred onto a hospital provided oxygen delivery device, and the study device will be removed from the room. The hospital provided device will be applied and titrated by the study investigator in liaison with the doctor and nurse responsible for the care of the patient. At this time a Masimo RD SET® Adt sensor (Masimo Corporation, Irvine, CA) will be applied to a finger and connected to a small portable pulse oximeter (sat801+, Bitmos, Düsseldorf, Germany). All pulse oximeter alarms will be silenced and the screen concealed to avoid influencing clinical management. The participant and nursing staff will be advised that the sensor should be disconnected when mobilising, but at all other times it should remain connected. Nursing staff will be instructed to measure SpO2 using their normal ward pulse oximeters and adjust oxygen as they normally would in accordance with their normal practice. This is expected to align with the Wellington Hospital COVID-19 Respiratory Support Pathway. After 24 hours of monitoring a study investigator will remove the finger sensor and disconnect the pulse oximeter. At this time the participants involvement in the study will end and they will not be permitted to participate in the study again.