It is the first AIoT continuous blood oxygen saturation monitoring system capable of early warning of cardiac arrest in the world. Through Bluetooth, the oximeter transmits oxygen saturation data to the Wifi Gateway, which then transmits the data to the cloud or to the local host for real-time monitoring. An early warning system for sudden cardiac arrest is also provided by the host using a proprietary deep learning model. Deep learning models are trained using high-density vital sign data from the US-based national representative ICU database. More than 80％ of cardiac arrest cases can be identified before six hours with the model prediction accuracy rate of 98％.