Investigating whether environmental factors such as air quality, pollen and socio-economic indices play affect the risk of perioperative respiratory adverse events in children

A single centre prospective observational cluster cohort study will be carried out at Perth Children’s Hospital in Western Australia. All children undergoing surgery under general anaesthesia who arrive in the PCH post-anaesthetic care unit (PACU) between 0800 and 1800 on weekdays during the data collection periods will be included in this study using a waiver of consent. There is no active participation for participants, all data is collected through the course of routine clinical care by anaesthetists and post-anaesthetic care unit (PACU) nurses and recorded on a paper data sheet. Pre-operative data collection will be done by anaesthetists and will involve recording anaesthetist-assessed respiratory risk factors (recent upper respiratory tract infection, history of asthma symptoms and/or diagnosis, parent/caregiver currently smoking, history of prematurity less than 32 weeks' gestation) and symptoms of sleep disordered breathing (snoring, incidence of trouble breathing at night, witnessed apnoea's, history of waking unrefreshed in the morning). This is collected as part of clinical care consultations prior to anaesthesia. The treating anaesthetist will record details of their anaesthetic management, and the incidence of any respiratory adverse events during induction, maintenance, emergence or peri-extubation periods of anaesthesia. The treating PACU nurse will record any incidence of respiratory adverse events during the patient's stay in PACU. Data collection will occur over four periods in 2024 to investigate the incidence of PRAE at timepoints that align with typical seasonal trends of air quality and pollen load. The first data collection period will occur over four weeks starting in February 2024, when PM2.5 and PM10 associated with wildfires and annual ozone concentrations are at their highest levels. The second data collection period will take place over 17 weeks between April and August, when air quality in Western Australia is most heavily impacted by prescribed/controlled burns, and the use of domestic wood heaters. The third data collection period will happen over 12 weeks beginning in August 2024, when the pollen counts are typically highest. The fourth data collection period will occur between October and December, when air quality is again adversely affected by ozone and prescribed burning activity. Data collected over these four periods will be complemented by previously collected prospective data collected for the POSSUM study (RGS0000005292; ACTRN12622000559718) which recruited Perth Children's Hospital (PCH) patients undergoing general anaesthesia between 03rd October and 23rd December 2022. No recorded data on Perth pollen counts exists for POSSUM data collected in October 2022, due to required service and maintenance on the pollen counting machinery. Data will therefore be collected in October 2024 to capture a complete set of data for the duration of the Perth pollen season, which typically runs from August to November. POSSUM data includes complete data sets for all parameters to be assessed in CHEETAH: respiratory risk factors, anaesthetic management and incidence of respiratory adverse events.