RESUMEN
OBJECTIVES: To ascertain the correlation between the partial pressure of oxygen (PaO2) and oxyhaemoglobin saturation by pulse oximetry (SpO2) in patients who were admitted to the emergency department with suspected acute respiratory failure. MATERIAL AND METHODS: A prospective, observational multicentre study was conducted in the emergency departments of 3 Spanish hospitals. RESULTS: The study included 166 patients who presented mean±standard deviation PaO2, SpO2 and fraction of inspired oxygen (FiO2) values of 61.64±17.3mmHg, 87.61±8.8% and 0.28±0.15%, respectively. The median PaO2/FiO2 and SpO2/FiO2 ratios were 256.6 and 359.2, respectively. The correlation between PaO2/FiO2 and the SpO2/FiO2 was 0.745 (P<.001). CONCLUSIONS: The SpO2/FiO2 ratio can be used to calculate PaO2/FiO2 and determine the oxygenation state of patients with acute respiratory failure.