Aims Chloral hydrate remains a popular sedative agent in Paediatrics because of an available oral formulation and relatively mild side effect profile. However, its use for MAG3 scanning can prove problematic because of its unpredictable onset, long duration, and the lack of a reversal agent.

The aims of this study were to identify:

• Whether sufficient time was given between administration and scanning for chloral hydrate to be effective.

• Whether appropriate doses were being administered.

• How many patients required repeated doses of sedation.

• How many scans were delayed or cancelled because of inadequate sedation.

• Ways to improve current practice.

Method A retrospective study looking at all patients from a general paediatric ward who underwent MAG3 scanning between August 2009 and April 2013. For each patient, data was recorded on dose, duration of action, number of doses given and recorded delay.

Results 11 cases underwent scanning during the study period. 100% of children received the current recommended dosage as per guidance of 50 mg/kg for less than 6 months and 75 mg/kg for over 6 months. Only 9% received chloral hydrate one hour prior to scanning as per protocol. 8/11 (73%) cases required additional doses of sedation in order to perform the scan. The number of additional doses required ranged from 1–8. The delay from initial dose to effective sedation ranged from 30–205 min with age, weight, duration of sedation prior to procedure and travelling distance to the hospital site impacting on this time. 100% of patients underwent scanning on the planned date but the child who incurred the longest delay was almost postponed.

Conclusion Children receiving chloral hydrate greater than 45 min prior to their scan were more effectively sedated, required fewer repeated doses and experienced less delay in the scan being completed. Older children, with an increased awareness of the clinical situation generally required several doses of sedation and would benefit from a higher initial dose being administered. It would also be appropriate to prescribe a second additional dose and reserve it for those who don’t respond after 45 min to avoid delay in subsequent administration.