Acute respiratory failure continues to be one of the most frequent causes of admission to Intensive Care services and one of the methods to treat these patients is high flow oxygen therapy with nasal cannulas. One of the most important problems experienced by intensivists in patients with respiratory failure treated with non-invasive support measures is to determine if a patient needs to be intubated or not and when is the best time to do so. Now, a study carried out by researchers from the group of Shock, Organic Dysfunction and Resuscitation of the Vall d'Hebron Institute of Research (VHIR) led by Dr. Ricard Ferrer, has defined a predictor of success or failure of high-flow oxygen therapy that allows detecting which patients will respond positively to therapy and not delay intubation in those who will not. The study is published in the https://www.atsjournals.org/doi/10.1164/rccm.201803-0589OC" American Journal of Respiratory and Critical Care Medicine.High-flow oxygen therapy allows up to 60 litters of warm and humidified oxygen to be administered, which improves both physiological and oxygenation parameters and comfort. "But this improvement can mask the clinical deterioration of the patient and delay intubation, and intuiting patients who should have intubated in the early stages leads to a worse prognosis," explains Dr. Oriol Roca, deputy physician of the Intensive Medicine Service of Vall University Hospital. d'Hebron and researcher of the Shock, Organic Dysfunction and Resuscitation group at VHIR. In fact, despite the treatments available, mortality in patients with acute respiratory failure remains high and the delay in intubation of the patient is associated with a worse prognosis. High-flow oxygen therapy is currently a standardized method in the treatment of acute respiratory failure in adults thanks to a study by the VHIR's Shock, Organic Dysfunction and Resuscitation research team, which in 2010 published the first series in the world in adult patients changing the paradigm of treatment of patients with acute respiratory failure. Until then, high-flow oxygen therapy was only used in paediatric patients and neonates."Until now, there was no precise diagnostic method to decide when to switch from high-flow nasal cannulation therapy (TAFCN) to intubation of the patient," says Dr. Berta Caralt, deputy medical unit of the Unit. postoperative of cardiac surgery (UPCC) within the Intensive Medicine Service of Vall d'Hebron. "The work verifies the validity of the ROX index, which is defined as the ratio between oxygenation and respiratory rate, to determine whether or not there is to intubate the patient and be able to do it within a window of time in which the prognosis does not worsen" says Dr. Roca. The limit of 12 hours The study involved 191 patients with pneumonia who had entered the ICU of 5 hospitals in the State and France. Approximately half of these patients were in the ICU of the University Hospital Vall d'Hebron.From the monitoring of these patients, researchers have been able to establish and develop models to see how the value of this index evolves in order to detect as soon as possible if a patient needs to be intubated."What we did was a follow-up of the evolution of the ROX index during the first 24 hours of treatment with high-flow oxygen therapy and we found that intubation beyond 12 hours could increase the risk of death," explains Dr. Caralt.Once demonstrated that this methodology allows to better identify patients at risk who do not evolve correctly with high-flow oxygen therapy, "the next steps will be, first, to determine if adding this index within the traditional intubation criteria we can intubate the patients before, if this is the case, then we will have to see if this earlier intubation is associated with an improvement in prognosis", concludes Dr. Roca.