Association between preoperative tropospheric ozone exposure and adverse perioperative respiratory events in paediatric patients: a single-centre retrospective cohort study.

BACKGROUND

Adverse respiratory events pose a risk to children undergoing anaesthesia. These events have been associated with environmental pollution exposure. We aimed to determine the impact of ground-level ozone (O3), a common air pollutant that causes inflammation and respiratory symptoms in infants and children, on perioperative respiratory adverse events in paediatric patients presenting from home for elective anaesthesia.

METHODS

We conducted a single-centre retrospective cohort study of all paediatric patients undergoing anaesthesia for an elective surgical or imaging procedure over a 4-yr period. Ozone exposure levels for the 15-day period leading up to the anaesthetic encounter were collected and quantified using local air quality sensors. The primary outcome was the occurrence of an adverse respiratory event under anaesthesia or in the immediate postoperative period. We also investigated associations with other known risk factors for adverse respiratory events.

RESULTS

The overall incidence of perioperative respiratory adverse events was 5.7%. Children in the high O3 exposure group had significantly higher rates of perioperative respiratory adverse events compared with those in the low O3 exposure group (8.0% vs 5.6%; relative risk, 1.43; 95% confidence interval, 1.02-2.03; P=0.042). This effect was also present among patients with underlying reactive airway disease or an active respiratory infection.

CONCLUSIONS

Ground-level O3 was associated with increased perioperative respiratory adverse events in paediatric patients undergoing elective anaesthesia. When considering the risk of these events, anaesthesiologists should consider the impact of O3 exposure in combination with other factors to determine overall perioperative risk.