Use of High Flow Nasal Cannula Oxygen During Acute Hypoxemic Respiratory Failure Related to Covid-19 and Interest of the Respiratory-oxygenation Index (ROX Index): an Observational Study

Brief Summary

Detailed Description

Nasal High Flow oxygen therapy (NHF) is one of the newer methods of oxygenation commonly used in critical care during acute hypoxemic respiratory failure (AHRF). For various reasons (fear of a putative risk of viral dispersion; initial recommendations for rapid intubation due to the rapid deterioration of patients), NHF seems to have been seldomly used during the current Covid-19 epidemic in France. However, the World Health Organization, and other scientific societies list NHF among the possible options for ventilatory support. One of the risks however, identified with NHF is to delay an intubation that would have become necessary. This delay seems to be associated with a poorer prognosis for patients. The respiratory-oxygenation index (termed ROX index) (defined as the ratio of pulse oximetry (SpO2) over inspired fraction in oxygen (FiO2) over respiratory rate (RR); SpO2/FiO2/RR) is used - along with other criteria - to assist the clinician in deciding whether or not to intubate patients on NHF for AHRF. In investigators'ICU, NHF is used in patients admitted for AHRFrelated to Covid-19 and the ROX index is measured and monitoring in investigators' patients. Investigators' initial experience - consistent with feedback from other ICUs - suggests that the respiratory rate of patients with Covid-19-related AHRF is sometimes lower than would be expected given the depth of the hypoxemia. In this case, the ROX index thresholds previously identified for predicting the success or failure of NHF could be different in the case of Covid-19-associated AHRF. The purpose of this work is to describe the use of NHF in Covid-19 patients with AHRF and the evolution of the ROX score over time in patients initially treated with NHF.

Primary Outcomes

Secondary Outcomes

• NHF failure(from date of NHF initiation until date of weaning from NHF or date of intubation whichever came first, assessed up to 2 months)
• NHF flow(from date of NHF initiation until date of weaning from NHF or date of intubation whichever came first, assessed up to 2 months)
• NHF inspired fraction in oxygen(from date of NHF initiation until date of weaning from NHF or date of intubation whichever came first, assessed up to 2 months)
• oxygenation(from date of NHF initiation until date of weaning from NHF or date of intubation whichever came first, assessed up to 2 months)
• respiratory status(from date of NHF initiation until date of weaning from NHF or date of intubation whichever came first, assessed up to 2 months)
• prediction of intubation(from date of NHF initiation until date of weaning from NHF or date of intubation whichever came first, assessed up to 2 months)
• prediction of NHF success(from date of NHF initiation until date of weaning from NHF or date of intubation whichever came first, assessed up to 2 months)