Background: The COVID-19 pandemic affected by the new Coronavirus SARS-CoV-2 continues to spread globally, increasing the burden on countries’ Health Care systems. Therefore, generating a platform to help diagnose and monitor COVID-19 patients remotely is considered an essential issue today. In particular, the SpO2 index plays a vital role in COVID-19 disease and is selected to monitor patients at health facilities and homes. This study aimed to evaluate the initial effectiveness of the remote SpO2 monitoring system in patients with mild - to - moderate COVID-19 diseases. Methods: This cross - section study was conducted on mild - to - moderate COVID-19 patients treated at the COVID-19 Intensive Care Center operated by Hue Central Hospital in Ho Chi Minh City, Vietnam Results: From August 2021 to October 2021, 32 COVID-19 patients were applied with SpO2 monitoring smartwatches. The mean age was 34.2 ± 12.0. Risk factors including obesity (25%), smoking (18.8%), hypertension (15.6%), and diabetes (12.5%). Most patients were admitted to the center due to shortness of breath (71.9%) and transferred from lower - level hospitals (62.5%). The main clinical symptoms are coughing, sneezing, runny nose (40.6%), followed by a decrease or loss of smell and taste (25%). 81.3% of patients had D-Dimer ≤ 500 ng/mL. 62.5% of patients had moderate COVID-19 grades. A total of 3,161 SpO2 measurements, including 8 alarms <
93%. The average SpO2 was 98.1 ± 0.2 %. All patients were discharged successfully. Conclusion: A remote SpO2 monitoring system is considered to have preliminary effectiveness in monitoring mild - to - moderate COVID-19 patients.