The effect of fasting practice on sedation with chloral hydrate

Infants undergo various painless imaging procedures frequently. Mild sedation is required in such cases to reduce anxiety as well as to ensure optimal performance of the procedure. The most frequently used sedative as a single drug is chloral hydrate. The issue of preprocedural fasting is a subject of contention. The purpose of this study was to assess the effect of the American Academy of Pediatrics (AAP)/American Society of Anesthesiology (ASA) fasting practice guidelines on the efficacy and success of the sedation with chloral hydrate.

The sedation records of 200 infants from 2 hospitals who underwent auditory brainstem response for evaluation of hearing loss were evaluated retrospectively. In the first hospital (group A), strict nulla per os (NPO) guidelines were followed in accordance with the guidelines published by the AAP/ASA, whereas in the second hospital (group B), no fasting period was required. All children were premedicated with chloral hydrate. We evaluated the sedation failure rate, total dose of chloral hydrate needed, adverse effects, overall sleep time, and time to discharge.

The average fasting period as expected was significantly longer in group A patients than in group B patients (5.7 +/- 1.7 vs. 2 +/- 0.2 hours; P < 0.001). Group A patients demonstrated a significantly higher failure rate to achieve sedation with the first dose of chloral hydrate compared with group B patients (21% vs.11%; P = 0.03), hence needing higher doses (83 +/- 31 vs. 61 +/- 21 mg/kg; P < 0.01), and were sedated for longer periods (103 +/- 42 vs. 73 +/- 48 minutes; P < 0.001) and discharged later. No difference was found in the adverse effect rate.

Fasting was associated with an increased failure rate of the initial sedation. As a consequence, an increased total dose of chloral hydrate was required inducing a prolonged sedation time. Presumably, this is a result of the fact that a hungry child is irritable and therefore more difficult to sedate.