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

Background and aim Telehealth is a strategy to expand the reach of pulmonary rehabilitation (PR). Smartphones can monitor and transmit oxygen saturation (SpO(2)) 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 O-2 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. SpO(2) and HR were evaluated at rest and during cycling and walking. SpO(2) 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 +/- 10 bpm. Usability was assessed with a questionnaire and direct observation. Results The smartphone oximeter was deemed easy to use. At rest, SpO(2) measures were valid in both groups (bias <2%, lower bound LoA -2 to 3%). During exercise, SpO(2) 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 > 10 bpm) in either group. Conclusions The smartphone oximeter did not record HR or SpO(2) accurately in patients with chronic lung disease during exercise, although SpO(2) was valid at rest. During exercise, patients with chronic lung disease should pause to ensure greatest accuracy of SpO(2) and HR measurement. (C) 2018 Published by Elsevier Ltd on behalf of Chartered Society of Physiotherapy.