Predictive Accuracy of the ROX Index for Re-Intubation in Mechanically Ventilated Patients With COVID-19

• Published in: Respiratory care Vol. 68; no. 8; p. 1067
• Main Authors: Okazaki, Yusuke, Nishikimi, Mitsuaki, Ishii, Junki, Ota, Kohei, Ohshimo, Shinichiro, Shime, Nobuaki
• Format: Journal Article
• Language: English
• Published: United States 01.08.2023
• Subjects: Cannula; COVID-19 - complications; COVID-19 - therapy; Humans; Intubation, Intratracheal - adverse effects; Oxygen Inhalation Therapy - adverse effects; Respiration, Artificial - adverse effects; Respiratory Insufficiency - therapy; Retrospective Studies; extubation; re-intubation; SARS-CoV-2; mechanical ventilation; breathing frequency; noninvasive ventilation; ROX index
• ISSN: 1943-3654
• DOI: 10.4187/respcare.10549

Several studies have suggested that high-flow nasal cannula (HFNC) is useful for respiratory support after extubation in subjects with COVID-19 pneumonia, whereas 18% subsequently needed to undergo re-intubation. This study aimed to evaluate whether the breathing frequency (f)-ratio of oxygen saturation (ROX) index, which has been shown to be useful for predicting future intubation, is also useful for re-intubation in subjects with COVID-19. We retrospectively analyzed mechanically ventilated subjects with COVID-19 who underwent HFNC therapy after extubation at 4 participating hospitals between January 2020-May 2022. We evaluated the predictive accuracy of ROX at 0, 1, and 2 h for re-intubation until ICU discharge and compared the area under the receiver operating characteristic (ROC) curve of the ROX index with those of f and S /F . Among the 248 subjects with COVID-19 pneumonia, 44 who underwent HFNC therapy after extubation were included. A total of 32 subjects without re-intubation were classified into the HFNC success group, and 12 with re-intubation were classified into the failure group. The overall trend that the area under the ROC curve of the ROX index was greater than that of the f and S /F was observed, although there was no statistical significance at any time point. The ROX index at 0 h, at the cutoff point of < 7.44, showed a sensitivity and specificity of 0.42 and 0.97, respectively. A trend of positive correlation between the time until re-intubation and ROX index at each time point was observed. The ROX index in the early phase of HFNC therapy after extubation was useful for predicting re-intubation with high accuracy in mechanically ventilated subjects with COVID-19. Close observation for patients with < 7.44 ROX index just after extubation may be warranted because of their high risk for re-intubation.