Towards Detecting Complete Chest Recoil from Smartphone Vibration Strength during Cardiopulmonary Resuscitation

Chest compressions (CC) is the most important means of treating sudden cardiac arrest (SCA). A critical factor of CC is complete chest recoil after each compression such that it returns to its initial position with no force exerted on the chest. For the first time, we show that commodity smartphones can estimate full chest recoil for providing real-time feedback. In our approach, a vibrating smartphone is placed between the patient's chest and the rescuer's hand. With our VibCPR system we research how accurate incomplete chest recoil can be detected from the vibration strength measured by the accelerometer at the moment of decompression. In an initial study, 24 participants apply our system to perform 10,950 CC. Based on a leave-one-subject-out evaluation, VibCPR correctly detects incomplete chest recoil at 80%, 75% and 72% balanced accuracy for three different smartphones, respectively.