Atmospheric particulate matter and hypoxaemia in Korean children receiving general anaesthesia: A retrospective analysis.

Background: The association between the concentration of atmospheric particulate matter on the day of surgery and the occurrence of intra-operative hypoxaemia in children receiving general anaesthesia is unclear.

Objective: To investigate the association between the exposure to particulate matter on the day of surgery and the occurrence of intra-operative hypoxaemia, defined as a pulse oximetry oxygen saturation of less than 90% for more than 1 min, in children.

Design: Retrospective study.

Setting: Single-centre.

Participants: Children aged 18 years or younger who received general anaesthesia between January 2019 and October 2020.

Intervention: Information on daily levels of particulate matter with a diameter 10 μm or less and 2.5 μm or less measured within a neighbourhood corresponding to the area defined by the hospital's zip code was obtained from publicly available air-quality data.

Main outcome measures: The primary outcome was intra-operative hypoxaemia, defined as a pulse oximetry oxygen saturation of less than 90% lasting for more than 1 min, manually verified by anaesthesiologists using vital sign registry data extracted at 2 s intervals.

Results: Of the patients finally analysed, 3.85% (489/13 175) experienced intra-operative hypoxaemia. Higher levels of particulate matter 10 μm or less in diameter (≥81 μg m -3 , 17/275, 6.2%) were associated with an increased occurrence of intra-operative hypoxaemia compared with lower particulate matter concentrations [<81 μg m -3 , 472/12 900, 3.7%; adjusted odds ratio, 1.71; 95% confidence interval (CI), 1.04 to 2.83; P  = 0.035].

Conclusion: The level of particulate matter on the day of surgery pose a risk of intra-operative hypoxaemia in children receiving general anaesthesia. If the concentrations of particulate matter 10 μm or less in diameter on the day of surgery are high, children receiving general anaesthesia should be managed with increased caution.