Improved use of the [13C]octanoic acid breath test as intra-individual parameter to study the effect of a prokinetic drug on gastric emptying in preterm infants with oral feeding intolerance

The [13C]octanoic acid breath test was used for the measurement of differences in gastric emptying in preterm infants for the evaluation of pharmacological therapy. In order to perform a good intra-individual comparison of the gastric emptying in preterm infants under non-standardisable test conditions, we adjusted t1/2 for variations in non-recovered label (=label retention) and introduced an “effective half 13CO2 breath excretion time” t1/2eff=t1/2/m expressed as min per percentage of the cumulative dose recovered. In a pilot study, we investigated the action of the gastrointestinal prokinetic drug cisapride on gastric emptying in seven premature infants, of whom four suffered from gastric stasis and three had constipation. The postnatal age and weight at the start of treatment ranged from 15 to 64 days and from 815 to 1635 g, respectively. All infants received the standard formula for premature infants (Nenatal, Nutricia). Cisapride was administered orally 0.2 mg/kg, four times daily. The changes in gastrointestinal motility were studied using the total bowel transit time of carmine red. After 7 days of treatment in all children, the gastric emptying coefficient and the half 13CO2 breath excretion time adjusted for label retention were improved (n=7, the gastric emptying coefficient range before treatment was 1.69–3.34 (mean 2.59±0.80) and after treatment it was 2.79–3.76 (mean 3.28±0.30); the half 13CO2 breath excretion time adjusted for label retention range before treatment was 3.0–14.7 min/% dose (mean 7.0±5.0) and after treatment 2.6–4.0 min/% dose (mean 3.1±0.6). The total bowel transit time was only slightly improved in two patients (n=7, mean total bowel transit time before: 23.7 h compared to mean total bowel transit time after 7 days of treatment: 35.5 h). Side effects during cisapride treatment were not seen. We conclude that in premature infants cisapride is effective in shortening gastric emptying time and reducing gastric stasis; the therapeutic role in constipation has to be further investigated.