Domiciliary pulse-oximetry at exacerbation of chronic obstructive pulmonary disease: prospective pilot study.
BACKGROUND
The ability to objectively differentiate exacerbations of chronic obstructive pulmonary disease (COPD) from day-to-day symptom variations would be an important development in clinical practice and research. We assessed the ability of domiciliary pulse oximetry to achieve this.


METHODS
40 patients with moderate-severe COPD collected daily data on changes in symptoms, heart-rate (HR), oxygen saturation (SpO2) and peak-expiratory flow (PEF) over a total of 2705 days. 31 patients had data suitable for baseline analysis, and 13 patients experienced an exacerbation. Data were expressed as multiples of the standard deviation (SD) observed from each patient when stable.


RESULTS
In stable COPD, the SD for HR, SpO2 and PEF were approximately 5 min(-1), 1% and 10l min(-1). There were detectable changes in all three variables just prior to exacerbation onset, greatest 2-3 days following symptom onset. A composite Oximetry Score (mean magnitude of SpO2 fall and HR rise) distinguished exacerbation onset from symptom variation (area under receiver-operating characteristic curve, AUC = 0.832, 95%CI 0.735-0.929, p = 0.003). In the presence of symptoms, a change in Score of ≥1 (average of ≥1SD change in both HR and SpO2) was 71% sensitive and 74% specific for exacerbation onset.


CONCLUSIONS
We have defined normal variation of pulse oximetry variables in a small sample of patients with COPD. A composite HR and SpO2 score distinguished exacerbation onset from symptom variation, potentially facilitating prompt therapy and providing validation of such events in clinical trials.
Academic Unit of Respiratory Medicine, Royal Free Campus, UCL Medical School, London, UK. j.hurst@medsch.ucl.ac.uk
John R
JR
Hurst
Gavin C
GC
Donaldson
Jennifer K
JK
Quint
James J P
JJ
Goldring
Anant R C
AR
Patel
Jadwiga A
JA
Wedzicha
D000203:Activities of Daily Living; D000368:Aged; D005260:Female; D006339:Heart Rate; D006801:Humans; D008297:Male; D018670:Monitoring, Ambulatory / Q000379:methods; D010092:Oximetry / Q000379:methods*; D010100:Oxygen / Q000097:blood; D010865:Pilot Projects; D029424:Pulmonary Disease, Chronic Obstructive / Q000503:physiopathology*
D010100:Oxygen