High-flow Oxygen and Nitric Oxide inhalation versus high-flow oxygen alone to prevent intubation in hypoxaemic Respiratory failure (HONOR): a pilot randomised controlled trial protocol.

Background: When conventional oxygen therapies fail, endotracheal intubation and invasive mechanical ventilation are the current standard of care in patients with acute hypoxaemic respiratory failure. However, invasive mechanical ventilation is associated with increased hospital and intensive care length of stay, healthcare costs, and morbidity and mortality. Inhaled nitric oxide has the potential to treat hypoxaemia and potentially prevent the need for invasive mechanical ventilation. Aims and objectives : The objective of this study is to examine the feasibility and effectiveness of high-flow oxygen and nitric oxide gas inhalation compared with high-flow oxygen alone in preventing invasive mechanical ventilation for patients with acute hypoxaemic respiratory failure. Methods: In this pilot, randomised controlled feasibility study, 40 patients admitted to the intensive care unit with acute hypoxaemic respiratory failure will be randomised on a 1:1 ratio to receive one of two interventions: high-flow oxygen and nitric oxide gas inhalation (intervention) or high-flow oxygen alone (control) via high-flow nasal cannula. Feasibility, demographic, outcome, and safety data will be collected at several timepoints during participants’ admission. Discussion: This protocol outlines a structured method for investigating the effects of inhaled nitric oxide gas in preventing invasive mechanical ventilation for patients with acute hypoxaemic respiratory failure. Considering the risks, costs, and poorer outcomes associated with invasive mechanical ventilation, less invasive means of respiratory support warrant further investigation. The study will assist in planning a larger, multi-centre definitive trial. Trial registration: This study is registered on the Australian New Zealand Clinical Trials Registry (ANZCTR): ACTRN12622001411730. Registered 4 ^th September 2022, https://www.anzctr.org.au/Trial/Registration/TrialReview.aspx?id=384881