Objective To report the largest study on the safety and effectiveness of sedation in paediatric ophthalmology in a nurse-led outpatient sedation unit.

Design Retrospective cohort study reviewing all children who underwent sedation from January 2006 to December 2010. Patients were sedated with 80 mg/kg of chloral hydrate (CH) given orally with top up dose given at half dose as required. All demographic data, sedation and procedure duration, sedation success and adverse events were recorded. Univariate and multiple regression analyses were performed to assess factors associated with success and complications.

Results Data was collected for 1509 sedation episodes. More boys were sedated compared with girls (56.3% vs 43.7% p=0.0003) with an average age of 23.86 months and weight of 11.76 kg. A higher proportion of patients had an American Society of Anaesthesiologists status of II than I (58.5%:41.5%, p=0.0001). Successful sedation was obtained in 96.69% of children with 4.77% requiring a top up dose to achieve this. The average sedation duration was 53.4 min (SD=21.5) with an average of 1.7 procedures performed; the most common being a detailed examination (93.5%) and electroretinogram (45.1%). Adverse events included paradoxical reaction (1.33%), oxygen desaturation (0.99%) and vomiting (0.53%). There were no serious complications or hospital admission. Multiple logistic regression analysis found weight greater than 15 kg and needing a top up dose to be significant risk factors for Failure (OR=2.49 and 8.69, respectively) and Adverse events (OR=2.1 and 3.97, respectively). Sex and American Society of Anesthesiologists Physical Status score did not significantly affect outcomes.

Conclusions CH sedation allows detailed examination and investigations in the majority of children with few side effects. Patients over 15 kg and need for a top up dose are risk factors for failure and adverse events. This is the largest study in the current literature looking at the use of CH sedation in ophthalmology and confirms its safety and effectiveness.