High-velocity nasal insufflation success assessment using ROX index in patients with acute respiratory failure

Abstract

Background High-velocity nasal insufflation (Hi-VNI) in patients with acute respiratory failure (ARF) gives humidified, heated oxygen, with a higher velocity, and gas flow up to 40 l/min, and FiO2 up to 1.0 through more comfortable, relatively small nasal prongs. respiratory rate-oxygenation (ROX) index is an easy bedside test, variable with time, and helps in decision making in the daily follow-up of patients on Hi-VNI. Aim The aim was to validate the accuracy of ROX index in the early detection of patients with ARF who will fail using Hi-VNI and need early intubation without worsening their clinical prognosis. Patients and methods A prospective observational cohort study was performed on 40 patients with ARF who received Hi-VNI treatment. Application of Hi-VNI was done once indicated, and after 2, 6, and 12 h, intensivists calculated ROX indices. Then, follow-up patients was performed for the need for intubation, ICU length of stay, and 28-day mortality. Results Patients treated with Hi-VNI were divided into two groups: the successful group and the unsuccessful group. A total of 20 patients (50%) required intubation after Hi-VNI. Their median ROX indices were 4.25, 4.6, and 4.8 after 2, 6, and 12 h, respectively. The ROX index can predict the risk of intubation in patients with ARF. However, in the successful group, ROX indices were 6.35, 6.29, and 7.05 after 2, 6, and 12 h, respectively. The ROX index was an accurate predictor of success (area under the curve=1.00). Conclusion In patients with ARF treated by Hi-VNI, the ROX index is a bedside test, daily used in ICU, and can early predict patients who will fail using Hi-VNI and need intubation, thus avoiding delayed intubation and worse clinical outcome.

Keywords

• acute respiratory failure
• high-velocity nasal insufflation
• rox index