Objective To assess the role of blood gas analysis as an auxiliary tool for detecting and predicting the progression of COVID-19 in patients. Research Methodology/Design A consecutive cohort study was conducted of 106 patients diagnosed with the novel coronavirus. Patients were divided into two groups based on age and the course of the disease (mild to moderate and severe). Blood gas analysis parameters were measured for all participants and results were compared between groups. Setting This study was conducted in the Department of Laboratory Medicine, The Third Affiliated Hospital, Southern Medical University, Guangzhou, China. Main Outcome Measures Arterial/alveolar oxygen partial pressure ratio, reduced hemoglobin fraction, sodium ion, lactic acid, oxygen saturation, oxygen partial pressure, and oxyhemoglobin fraction. Results Findings indicated statistically significant differences between the two groups in the measured parameters. Conclusion Blood gas analysis has the potential to more accurately assess the progression of COVID-19 in elderly patients, specifically related to respiratory and acid-base balance issues. Implications for Clinical Practice This study underscores the importance for bedside nurses to pay close attention to acid-base balance, lung ventilation/ventilation function, and hypoxia status in elderly critically ill patients with COVID-19, in order to more effectively diagnose and predict the progression of the disease.