ROX index versus HACOR scale in predicting success and failure of high-flow nasal cannula in the emergency department for patients with acute hypoxemic respiratory failure: a prospective observational study

Abstract Background High-flow nasal cannula has been a promising initial respiratory support measure for patients with acute hypoxemic respiratory failure (AHRF) in the emergency department (ED). However, delayed detection of HFNC failure is associated with increased mortality. The ROX index is a tool that can help predict HFNC success. Nonetheless, its utility in ED patients is limited, and no studies have compared it with the HACOR scale, another tool that may be as accurate in predicting HFNC failure. Therefore, we aimed to compare the prognostic utility of the ROX index and the HACOR scale in emergency AHRF patients. Methods This prospective observational study was conducted at the ED of Siriraj Hospital, Thailand, between August 2018 and February 2020. Adult patients with AHRF requiring HFNC in the ED were included. The ROX index and the HACOR scale were measured at 1, 2, and 6 h after HFNC initiation. The primary outcome was HFNC success, defined as no intolerance or escalation towards mechanical ventilation or non-invasive ventilation within 48 h. Results A total of 75 patients were enrolled; 52 (69.3%) had a successful treatment. The ROX index was higher in the success group, while the HACOR scale was lower at all timepoints. The ROX index yielded generally higher discrimination capacity based on the area under the receiver operating characteristic curve (AUROC) than the HACOR scale [AUROC at 1, 2, and 6 h = 0.815, 0.784, 0.853 for ROX in predicting HFNC success and 0.733, 0.690, and 0.764 for HACOR in predicting HFNC failure]. The ROX index measured at 6 h at the cut-point of 4.88 had 92.98% sensitivity, 61.11% specificity, 88.33% positive predictive value, and 73.33% negative predictive value with a diagnostic accuracy of 85.33%. Conclusion The ROX index had superior prognostic utility in predicting HFNC outcome (success/failure) compared to the HACOR scale in patients with AHRF in the ED setting. Moreover, it is less complex and more efficient to be employed at bedside. Therefore, the ROX index is a more appropriate tool to guide further management and potential escalation therapy for AHRF patients with HFNC therapy initiated in the ED

Assessment of Prehospital Management of Patients Transported to a Thai University Hospital

Objective: To assess the quality of prehospital care given to patients transported to a Thai university hospital.    Methods: This prospective observational study collected data from EMS providers who transported patients to Siriraj Hospital during August 2017 to November 2017. Collected data was evaluated by at least 2 EMS medical directors for appropriateness of EMS dispatch and prehospital care. The primary outcome was to determine the quality of prehospital management among patients transported by EMS. Inter-rater variability in the evaluation of patient care between EMS medical directors and medical providers in the emergency department (ED) was performed using Cohen’s kappa coefficient, with a value lower than 0.7 indicating significant variability. Results: Data was collected from 246 EMS providers that transported patients to our center. Evaluation by EMS medical directors found EMS dispatch to be appropriate in 216 cases (87.8%), and patient management to be appropriate in 198 cases (80.5%). Inappropriate prehospital management was found most often in patients who presented with out-of-hospital cardiac arrest (OHCA) (87.5%), and with chest pain (63.6%). Medical providers in the ED rated prehospital management to be appropriate in 93.1% of cases. Cohen’s kappa coefficient between EMS medical directors and ED providers was 0.2, which indicates significant variability between the two groups of assessors. Conclusion: Quality assessment of the Thai EMS system revealed opportunities for improvement in prehospital management of patients dispatched by Thai EMS. Moreover, this study found variability in the evaluation of prehospital care between medical providers at the ED and EMS medical directors. Information from this study will help to influence and guide improvement in prehospital patient care in Thailand

Ratio of Oxygen Saturation to Inspired Oxygen, ROX Index, Modified ROX Index to Predict High Flow Cannula Success in COVID-19 Patients: Multicenter Validation Study

Introduction: High-flow nasal cannula (HFNC) is a respiratory support measure for coronavirus 2019 (COVID-19) patients that has been increasingly used in the emergency department (ED). Although the respiratory rate oxygenation (ROX) index can predict HFNC success, its utility in emergency COVID-19 patients has not been well-established. Also, no studies have compared it to its simpler component, the oxygen saturation to fraction of inspired oxygen (SpO2/FiO2 [SF]) ratio, or its modified version incorporating heart rate. Therefore, we aimed to compare the utility of the SF ratio, the ROX index (SF ratio/respiratory rate), and the modified ROX index (ROX index/heart rate) in predicting HFNC success in emergency COVID-19 patients.Methods: We conducted this multicenter retrospective study at five EDs in Thailand between January–December 2021. Adult patients with COVID-19 treated with HFNC in the ED were included. The three study parameters were recorded at 0 and 2 hours. The primary outcome was HFNC success, defined as no requirement of mechanical ventilation at HFNC termination.Results: A total of 173 patients were recruited; 55 (31.8%) had successful treatment. The two-hour SF ratio yielded the highest discrimination capacity (AUROC 0.651, 95% CI 0.558-0.744), followed by two-hour ROX and modified ROX indices (AUROC 0.612 and 0.606, respectively). The two-hour SF ratio also had the best calibration and overall model performance. At its optimal cut-point of 128.19, it gave a balanced sensitivity (65.3%) and specificity (61.8%). The two-hour SF≥128.19 was also significantly and independently associated with HFNC failure (adjusted odds ratio 0.29, 95% CI 0.13-0.65; P=0.003).Conclusion: The SF ratio predicted HFNC success better than the ROX and modified ROX indices in ED patients with COVID-19. With its simplicity and efficiency, it may be the appropriate tool to guide management and ED disposition for COVID-19 patients receiving HFNC in the ED