A smartphone oximeter with a fingertip probe for use during exercise training: usability, validity and reliability in individuals with chronic lung disease and healthy controls

Abstract

Background and aim: Telehealth is a strategy to expand the reach of pulmonary rehabilitation (PR). Smartphones can monitor and transmit oxygen saturation (SpO₂) and heart rate (HR) data to ensure patient safety during home-based or other exercise. The purpose of this study was to evaluate the usability, validity and reliability of a Kenek O₂ pulse oximeter and custom prototype smartphone application (smartphone oximeter) during rest and exercise in healthy participants and those with chronic lung disease.

Methods: Fifteen individuals with chronic lung disease and 15 healthy controls were recruited. SpO₂ and HR were evaluated at rest and during cycling and walking. SpO2 was valid if the mean bias was within +±2%, the level of agreement (LoA) was within ±4%; HR was valid if the mean bias was within ±5 beats per min (bpm), LoA was within ±10bpm. Usability was assessed with a questionnaire and direct observation.

Results: The smartphone oximeter was deemed easy to use. At rest, SpO₂ measures were valid in both groups (bias <2%, lower bound LoA -2 to 3%). During exercise, SpO₂ measurement did not meet validity and reliability thresholds in the patients with chronic lung disease, but was accurate for the healthy controls. HR recording during exercise or rest was not valid (LoA>10bpm) in either group.

Conclusions: The smartphone oximeter did not record HR or SpO₂ accurately in patients with chronic lung disease during exercise, although SpO₂ was valid at rest. During exercise, patients with chronic lung disease should pause to ensure greatest accuracy of SpO₂ and HR measurement.

Keywords: Chronic obstructive pulmonary disease; Oxygen saturation; Pulmonary rehabilitation; Telerehabilitation; Usability.