Increasing support by nasal high flow acutely modifies the ROX index in hypoxemic patients: A physiologic study

• Published in: Journal of critical care Vol. 53; pp. 183 - 185
• Main Authors: Mauri, Tommaso, Carlesso, Eleonora, Spinelli, Elena, Turrini, Cecilia, Corte, Francesca Dalla, Russo, Riccarda, Ricard, Jean-Damien, Pesenti, Antonio, Roca, Oriol, Grasselli, Giacomo
• Format: Journal Article
• Language: English
• Published: United States Elsevier Inc 01.10.2019; Elsevier Limited
• Subjects: Accuracy; Acute hypoxemic respiratory failure; Aged; Blood Gas Analysis; Critical care; Cross-Over Studies; Electrical impedance tomography; Female; Gas flow; Hemodynamics; Humans; Hypoxia - physiopathology; Hypoxia - prevention & control; Intubation; Male; Middle Aged; Monitoring; Nasal high flow; Noninvasive Ventilation - methods; Nose; Oxygen Inhalation Therapy; Prospective Studies; Respiratory Insufficiency - etiology; Respiratory Insufficiency - physiopathology; Respiratory Insufficiency - therapy; Respiratory Rate; Success; Ventilators; Italy; RR; Electrical impedance tomography; EIT; ΔEELV; AHRF; Nasal high flow; ROX; Acute hypoxemic respiratory failure; NHF; Monitoring
• ISSN: 0883-9441; 1557-8615
• DOI: 10.1016/j.jcrc.2019.06.020

The ROX (Respiratory rate-OXygenation) index is an early predictor of failure of nasal high flow (NHF), with lower values indicating higher risk of intubation. We measured the ROX index at set flow rate of 30 and 60 l/min in 57 hypoxemic patients on NHF. Patients with increased ROX index values at higher flow (n = 40) showed worse baseline oxygenation, higher respiratory rate and lower ROX index in comparison to patients with unchanged or decreased ROX index values (n = 17). The ROX index variation between flows was correlated with the change in end expiratory lung volume. Set flow rate during NHF might impact the ROX index value.