An abnormal respiratory rate is often the earliest sign of critical illness. A reliable estimate of respiratory rate is vital in the application of remote telemonitoring systems, which may facilitate early supported discharge from hospital or prompt recognition of physiological deterioration in high-risk patient groups. Traditional approaches use analysis of respiratory sinus arrhythmia from the electrocardiogram (ECG), but this phenomenon is predominantly limited to the young and healthy. Analysis of the photoplethysmogram (PPG) waveform offers an alternative means of non-invasive respiratory rate monitoring, but further development is required to enable reliable estimates. This review conceptualizes the challenge by discussing the effect of respiration on the PPG waveform and the key physiological mechanisms that underpin the derivation of respiratory rate from the PPG.

Original publication

DOI

10.3109/03091902.2011.638965

Type

Journal article

Journal

Journal of medical engineering & technology

Publication Date

01/2012

Volume

36

Pages

1 - 7

Addresses

Nuffield Department of Medicine, University of Oxford, Oxford, OX3 7BN, UK. djmeredith@doctors.org.uk

Keywords

Humans, Photoplethysmography, Monitoring, Physiologic, Respiration, Respiratory Rate