Background
In 2013, outpatient use of chloral hydrate (CH) was limited and other alternatives such as oral pentobarbital (PB) were explored to achieve conscious sedation in young children for transthoracic echocardiography (TTE). We aimed to assess efficacy and safety of the two medications.

Methods
Clinical information, from a computerized database, about children who received sedation with either CH or PB for TTE at our center (2008-2015) was reviewed, and the two groups were compared for sedation effectiveness and complications.

Results
Three thousand eight hundred fifty one pediatric patients (median age 8 months) underwent conscious sedation during TTE (mean doses CH 50 mg/kg, PB 4 mg/kg). Demographic characteristics of the two groups were similar. Sedation failure rate (CH 2.4%, PB 2.9%, P = NS), need for supplemental doses (CH 17.9%, PB 16.2%, P = NS), and overall adverse event rate (PB 1.4%, CH 1.9%; P = NS) were similar in the two groups. There were fewer episodes of respiratory depression with PB (0.3% vs 1.6%, P < 0.05). The rate of paradoxical reactions was higher with PB (1% vs 0.03%, P < 0.05). Increasing age predicted the need for supplemental doses and for sedation failure in both groups. Neonates (7.5% vs 0%) and infants (2% vs 0.6%) given CH were more likely to develop adverse reactions.

Conclusion
Chloral hydrate and PB are equally effective. However, CH is associated with an increased incidence of transient desaturation, while PB is associated with an increased incidence of a paradoxical reaction. Increasing age is predictive of the need for supplemental doses and for failure of sedation in both groups.