A Randomised Controlled Trial of High-Flow Nasal Oxygen Versus Standard Oxygen Therapy in Critically Ill Immunocompromised Patients

Overview

Acute respiratory failure (ARF) is the leading reason for ICU admission in immunocompromised patients. Usual oxygen therapy involves administering low-to-medium oxygen flows through a nasal cannula or mask \[with or without a bag and with or without the Venturi system\] to achieve SpO2≥95%. Oxygen therapy may be combined with non-invasive ventilation \[NIV\] providing both end-expiratory positive pressure and pressure support. However, in a recent trial by our group, non-invasive ventialtion \[NIV\] was not superior over oxygen without NIV. High-flow nasal oxygen \[HFNO\] therapy is a focus of growing attention as an alternative to standard oxygen therapy. By providing warmed and humidified gas, HFNO allows the delivery of higher flow rates \[of up to 60 L/min\] via nasal cannula devices, with Fraction of inspired oxygen (FiO2) values of nearly 100%. Physiological benefits of HFNO consist of higher and constant FiO2 values, decreased work of breathing, nasopharyngeal washout leading to improved breathing-effort efficiency, and higher positive airway pressures associated with better lung recruitment. Clinical consequences of these physiological benefits include alleviation of dyspnoea and discomfort, decreases in tachypnoea and signs of respiratory distress, a diminished need for intubation in patients with severe hypoxemia, and decreased mortality in unselected patients with acute hypoxemic respiratory failure However, although preliminary data establish the feasibility and safety of this technique, HFNO has never been properly evaluated in immunocompromised patients. Thus, this project aims at demonstrating that HFNO is superior to low/medium-flow (standard) oxygen, minimising day-28 mortality

After discussion at the investigator meeting and based on comments from the Data and Safety Monitoring Board on May 12, 2016, the DSMB has highlighted the need of the interim analysis (already planned) as benefits from high flow oxygen may be observed after 400 inclusions. Update on June 16, 2017: The number of patients enrolled is 488 and the inclusion rate is increasing steadily. The interim analysis has been performed as scheduled and the DSMB decided that nothing should be changed.