Time course of blood oxygen saturation responding to short-term fine particulate matter among elderly healthy subjects and patients with chronic obstructive pulmonary disease

• Published in: The Science of the total environment Vol. 723; p. 138022
• Main Authors: Xia, Xi, Qiu, Hong, Kwok, Timothy, Ko, Fanny W.S., Man, Chung Ling, Ho, Kin-Fai
• Format: Journal Article
• Language: English
• Published: Netherlands Elsevier B.V 25.06.2020
• Subjects: acute effects; acute exposure; Air pollution; atmospheric pressure; blood; carbon monoxide; China; COPD; elderly; gas exchange; health status; monitoring; nitrogen; oxygen; Oxygen saturation; ozone; particulates; pathogenesis; patients; pollutants; Real-time monitoring; respiratory tract diseases; Time course; China; Time course; SpO2; IQR; CO; Oxygen saturation; Real-time monitoring; dfs; NO2; PM2.5; Air pollution; BMI; COPD; VM cpm
• ISSN: 0048-9697; 1879-1026; 1879-1026
• DOI: 10.1016/j.scitotenv.2020.138022

Patients with chronic obstructive pulmonary disease (COPD) often experience deteriorating gaseous exchange which in turn may result in declines in blood oxygen saturation (SpO2). Increasing evidence has also shown that elevated levels of fine particulate matter (PM2.5) may contribute to COPD pathogenesis. However, the acute effects of PM2.5 on SpO2 among COPD patients remain unclear, especially for its time course. Therefore, we conducted this panel study with 3-day real-time monitoring for personal PM2.5 exposure and concurrent SpO2 of 39 participants (20 COPD patients, 19 healthy participants), aged 60 to 90 years, in Hong Kong to explore the acute effects of personal PM2.5 exposure on SpO2 (within minutes to hours). We applied a linear mixed effect model to examine the associations between personal PM2.5 and SpO2, while adjusting for temporal trend, personal characteristics, weather conditions, and co-exposure to gaseous pollutants (ambient ozone, nitrogen dioxides, carbon monoxide, and atmospheric pressure). We found that short-term exposure to PM2.5 might result in acute declines of SpO2 within minutes, and the effects would last for several hours. An interquartile range increase of personal PM2.5 exposure (17.2 μg/m3) was associated with −0.19% (95% CI: −0.26% to −0.12%) changes of concurrent SpO2 for all participants. The most significant decline was observed at lag0-3 h, and then became insignificant at lag0-12 h. At lag0-1 h, estimated mean changes of SpO2 were −0.40% (95% CI: −0.55% to −0.24%) for COPD patients and −0.09% (95% CI: −0.23% to 0.06%) for healthy participants. Compared with healthy participants, the effects of PM2.5 exposure on SpO2 for COPD patients were slightly stronger and more acute. Reducing PM2.5 concentrations might be a useful approach to improve health status and reduce exacerbations for COPD patients. [Display omitted] •The first study with real-time monitoring for both personal PM2.5 and oxygen saturation (SpO2)•PM2.5 might result in acute decline of SpO2 within minutes.•Decline of SpO2 is stronger and more acute among COPD patients.•Acute PM2.5-mediated blood oxygen desaturation should be aware.