Use of radiograph scoring systems to assess pulmonary disease severity in patients with COVID-19 pneumonia

BACKGROUND: Severe acute respiratory syndrome coronavirus 2 causes pneumonia in most hospitalized patients, often leading to hypoxemia and the need for supplemental oxygen. While chest computed tomography is highly sensitive, chest radiographs (CXR) offer a practical alternative in high-volume settings. Scoring systems like Radiographic Assessment of Lung Edema (RALE) and BRIXIA standardize CXR interpretation and quantify severity, but their relationship with oxygen delivery requirements in coronavirus disease 2019 (COVID-19) patients remains unclear. AIM: To evaluate whether the initial emergency department (ED) radiograph could predict subsequent oxygen support requirements. The secondary aim was to assess inter- and intra-rater agreement of the scoring systems. METHODS: This retrospective cohort study examined consecutive COVID-19 patients presenting to a large tertiary hospital ED (May-June 2020) who required admission and underwent CXR within 24 hours of arrival. Infiltrate severity on ED radiographs was scored using the BRIXIA and RALE systems. Oxygen support was categorized by delivery device, and associations were examined using logistic regression. RESULTS: high flow nasal cannula/continuous positive airway pressure/Bi-level positive airway pressure. Prediction for non-rebreather mask yielded lower AUCs (BRIXIA: 0.65; RALE: 0.62), with nasal cannula use showing limited discrimination (BRIXIA: 0.56; RALE: 0.54). During hospitalization, predictive performance remained modest across all modalities. The AUCs for intubation were 0.63 (BRIXIA) and 0.62 (RALE), while for high flow nasal cannula/continuous positive airway pressure/Bi-level positive airway pressure, values dropped slightly to 0.62 and 0.59, respectively. Non-rebreather mask prediction maintained an AUC of 0.62 for both scores, and nasal cannula predictions remained low (BRIXIA: 0.56; RALE: 0.52). Inter- and intra-rater agreement was excellent in both scores, with inter-rater agreement at 95% (95%CI: 0.94-0.96) and intra-rater agreement at 97% (95%CI: 0.96-0.98) for BRIXIA and 98% (95%CI: 97-98) for RALE. CONCLUSION: Both RALE and BRIXIA scores effectively predicted the need for advanced respiratory support in ED COVID-19 patients and demonstrated excellent inter-rater and intra-rater reliability. While their predictive power diminished during hospitalization, both scores remain valuable for initial triage, with BRIXIA particularly useful for ruling out the need for high-level oxygen support.