Sleep Quality - Comparing the Effect of Ondansetron or Dexamethasone Given as Routine Prophylaxis Intraoperatively to Prevent Post Operative Nausea and Vomiting (SCORPION)

Postoperative nausea and vomiting (PONV) are a common complication after anaesthesia. Therefore, it is standard practice to administer either ondansetron and/or dexamethasone intraoperatively as prophylaxis. PONV affects up to 30-40% of the general surgical population and up to 80% of high-risk patients, making it one of the most distressing complications of the perioperative period.Uncontrolled PONV prolongs recovery room stay, increases unplanned hospital re-admissions, and is consistently identified by patients and families as one of the most undesirable aspects of the surgical experience. It was ranked in the top 10 research priorities in perioperative medicine in a recent large consumer engagement study involving over 350 children.

Ondansetron, a 5-HT3 receptor antagonist, and dexamethasone, a corticosteroid, are the two most widely used agents for PONV prophylaxis in paediatric anaesthesia, often administered in combination.Dexamethasone exerts well-documented glucocorticoid effects, including modulation of the hypothalamic-pituitary-adrenal (HPA) axis, suppression of endogenous cortisol secretion, and direct actions on brain structures involved in arousal and sleep regulation, including the hippocampus, hypothalamus, and limbic system.a single intraoperative dose of dexamethasone (0.1-0.5 mg/kg) has been shown to produce measurable HPA axis suppression lasting 24-48 hours postoperatively in children, as well as transient elevations in blood glucose and behavioural changes including hyperactivity, irritability, and emotional lability.

Sleep is a critical component of paediatric postoperative recovery. Disrupted postoperative sleep has been associated with increased pain perception, impaired immune function, heightened parental anxiety, and prolonged behavioural disturbance following surgery. Glucocorticoids are known to disrupt sleep architecture, including fragmentation of sleep, suppression of slow-wave sleep, and reductions in total sleep time. In children, the effects of a single perioperative dose of dexamethasone on sleep remain poorly characterised. In contrast, ondansetron does not directly affect the HPA axis or glucocorticoid receptors, and its central effects are limited primarily to 5-HT3 receptor blockade, with no established direct mechanism for sleep disruption. Postoperative negative behavioural changes (PNBC) in children, sometimes referred to as "new-onset behavioural problems", are a recognised sequela of paediatric anaesthesia and surgery, affecting up to 54% of children in the first 2 weeks following surgery. The potential role of perioperative dexamethasone in exacerbating these changes through glucocorticoid-mediated effects on the developing brain has not been systematically examined. Understanding whether the choice of PONV prophylaxis agent influences postoperative sleep quality and behaviour could have important implications for anaesthetic practice and family-centred postoperative care.

This study aims to investigate the impact of intraoperative intravenous dexamethasone vs ondansetron administered for prophylaxis of postoperative nausea and vomiting (PONV) on postoperative sleep, behaviour and recovery in children undergoing general anaesthesia.