I. Introduction
Blood oxygen saturation ( SpO 2 ) and heart rate (HR) are two major indicators of monitoring the overall health of an individual. They also act as the earliest critical vital signs which provide a primary warning of forthcoming life threatening condition and illness [1] , [2] . Lack of sufficient oxygen level (above 90% for a healthy person) can lead to hypoxia (lack of oxygen) responsible for brain damage and it also affects proper body functioning. On the other hand, HR is an indicator of the soundness of the cardiac system as well as the whole human body. It is not only the key indicator of cardiovascular diseases like heart failure, arrhythmia, cardiac arrest, sudden cardiac death but also any dysfunction of any part of the human body. That is why, SpO 2 and HR are commonly monitored parameters for patients in intensive care units (ICU), critical care units (CCU), emergency care, sleep studies, pediatric and neonatal care.