Fig. 2: Overview of the loss of pulse detection algorithm.
From: Automated loss of pulse detection on a consumer smartwatch
a, Timeline shows the detection sequence that culminates in a call to emergency services. The algorithm consists of two initial phases that identify potential pulsatile-to-pulseless transitions. These are followed by user-facing alerts that consist of haptics, audio and visual notifications that invite user interaction. If the user is persistently unresponsive, a call is placed to emergency services. algo, algorithm. b, Design mocks show the user-facing stages, including the de-escalation flow that is invoked by responsive users. c, Technical details of the loss of pulse detection algorithm are shown with a description of data processing for the PPG and accelerometer sensors. DSP, digital signal processing; ML, machine learning.
