Apnoea

Unpublished institutional retrospective data showed a 5.7% desaturation rate with propofol-esketamine compared to 21% with propofol-remifentanil. Apnoea lasting one minute or more was chosen as the primary endpoint over hypoxaemia because hypoxaemia cannot distinguish between desaturation from airway obstruction and desaturation from true apnoea or hypoventilation. A systematic review of capnography monitoring found that detecting transient, brief apnoea events tends to lead to unnecessary interventions without improving patient outcomes, supporting the adoption of a one-minute threshold. If the true effect size is more moderate than 75%, the study may lack sufficient power to demonstrate a statistically significant difference in desaturation. The trial's sample size calculation projects a 75% relative risk reduction in desaturation with esketamine versus remifentanil. Accurate apnoea detection is ensured by inserting a nasal or oral airway adjunct in all patients before the biopsy begins and having a dedicated airway anaesthetist monitor solely for respiratory events. Apnoea lasting more than 30 seconds triggers manual mask ventilation until spontaneous breathing resumes. The Wor…