Daytime Variation of Chloral Hydrate-Associated Sedation Outcomes: A Propensity-Matched Cohort Study.

Background: Physiological processes influencing a drugs' efficacy change substantially over the course of the day. However, it is unclear whether there is an association between the sedative success rate of chloral hydrate and the time of day. We conducted a retrospective study of 41,831 cases, to determine if there was a difference in sedation success rate with chloral hydrate in children seen in the morning and afternoon.

Methods: Patients who accepted the sedation service were included. Eligible patients were divided into two cohorts of morning and afternoon cases, according to the time of day when the initial dose of chloral hydrate was administered. To ensure that the two groups were comparable, a propensity score matching method was utilized.

Results: The success rate with the initial dose of chloral hydrate was higher in patients who received sedation services in the afternoon. In the subgroup analysis, the afternoon cases had a higher sedation success rate compared to the morning cases in male patients; whereas, in female patients, no difference was detected between the morning versus afternoon cases.

Conclusions: These results show that the afternoon cases had a higher sedation success rate than the morning cases, despite the afternoon cases receiving relatively lower initial dose than the morning cases. However, the clinical significance remains to be discussed, and further prospective studies are needed to validate the findings.