The Respiratory Rate-Oxygenation Index predicts failure of post-extubation high-flow nasal cannula therapy in intensive care unit patients: a retrospective cohort study

Abstract

Objective To investigate the applicability of the Respiratory Rate-Oxygenation Index to identify the risk of high-flow nasal cannula failure in post-extubation pneumonia patients. Methods This was a 2-year retrospective observational study conducted in a reference hospital in Bogotá, Colombia. All patients in whom post-extubation high-flow nasal cannula therapy was used as a bridge to extubation were included in the study. The Respiratory Rate-Oxygenation Index was calculated to assess the risk of post-extubation high-flow nasal cannula failure. Results A total of 162 patients were included in the study. Of these, 23.5% developed high-flow nasal cannula failure. The Respiratory Rate-Oxygenation Index was significantly lower in patients who had high-flow nasal cannula failure [median (IQR): 10.0 (7.7 - 14.4) versus 12.6 (10.1 - 15.6); p = 0.006]. Respiratory Rate-Oxygenation Index > 4.88 showed a crude OR of 0.23 (95%CI 0.17 - 0.30) and an adjusted OR of 0.89 (95%CI 0.81 - 0.98) stratified by severity and comorbidity. After logistic regression analysis, the Respiratory Rate-Oxygenation Index had an adjusted OR of 0.90 (95%CI 0.82 - 0.98; p = 0.026). The area under the Receiver Operating Characteristic curve for extubation failure was 0.64 (95%CI 0.53 - 0.75; p = 0.06). The Respiratory Rate-Oxygenation Index did not show differences between patients who survived and those who died during the intensive care unit stay. Conclusion The Respiratory Rate-Oxygenation Index is an accessible tool to identify patients at risk of failing high-flow nasal cannula post-extubation treatment. Prospective studies are needed to broaden the utility in this scenario.

To: The Respiratory Rate-Oxygenation Index predicts failure of post-extubation high-flow nasal cannula therapy in intensive care unit patients: a retrospective cohort study

“…We have read with interest the study entitled “The respiratory rate-oxygenation index predicts failure of post extubation high-flow nasal cannula therapy in intensive care unit patients: a retrospective cohort study” published by Fuentes et al in this journal. ( 1 ) The authors proposed the respiratory rate-oxygenation (ROX) index as a predictor of post extubation high-flow nasal cannula (HFNC) therapy failure in pneumonia patients admitted to the intensive care unit. The ROX index is the ratio between oxygen saturation (SpO 2 ) and fraction of inspired oxygen (FiO 2 ) to respiratory rate.…”

“…The ROX index was statistically lower in patients who had HFNC failure than in those who tolerated bridge therapy [median (IQR): 10.0 (7.7 - 14.4) versus 12.6 (10.1 - 15.6); p = 0.006] in terms of the ROX index to predict extubation failure, and the area under the ROC curve was 0.64 (95%CI: 0.53 - 0.75; p = 0.06). ( 1 ) The application of this index has promise in quantifying the increase in the work of breathing imposed on these patients; however, we have some concerns. There is no universal agreement on the cutoff value of the ROX index, and in different studies, it varies from 2.7 to 9.2.…”

Reply to: The Respiratory Rate-Oxygenation Index predicts post-extubation high-flow nasal cannula therapy failure in intensive care unit patients: a retrospective cohort study

“…We want to thank Francesco Alessandri, Pierfrancesco Tozzi, and Antonio Esquinas for their interest in our study. ( 1 ) Their constructive feedback is greatly appreciated. We have thoroughly reviewed their concerns and are pleased to provide the following responses.…”