NCT02399878.

Among adult patients undergoing noncardiac surgery at 3 hospitals, having a preoperatively diagnosed PFO was significantly associated with increased risk of perioperative ischemic stroke within 30 days after surgery. Further research is needed to confirm these findings and to determine whether interventions would decrease this risk.

Consent to participate: Written informed consent was obtained from all subjects or their legally authorised representatives. Consent for publication: Not applicableAvailability of data and material: De-identified data collected during the trial will be made available upon reasonable request to researchers who provide a methodologically sound proposal, after approval by the study authors, and with a signed data access agreement. Questions about data are handled by the corresponding author.

High intraoperative opioid dose is a modifiable anaesthetic factor that varies in the practice of individual anaesthetists and affects postoperative outcomes. Conservative standards for intraoperative opioid dosing may reduce the risk of postoperative readmission, particularly in ambulatory surgery.