title: Increased respiratory drive as an inhibitor of oral feeding of preterm infants.
abstract: This study was designed to determine whether increased respiratory drive induced by inhalation of carbon dioxide would alter the reflex and voluntary components of feeding. For 10 preterm infants (mean +/- SD: postconceptional age at study, 34 +/- 2 weeks; weight, 2.1 +/- 0.2 kg), four trials of nutritive feeding were offered: two while the infants were inhaling a gas mixture containing 40% oxygen and two while the infants were breathing 40% oxygen and 7% carbon dioxide. Nasal airflow was monitored with a pneumotachygraph. Pressure-sensitive catheters in the esophagus and in the feeding nipple were used to detect swallowing and sucking. Sucking frequency and pattern, rate of swallowing, end-tidal carbon dioxide, and minute ventilation were recorded for 30-second epochs during feeding. When the inhaled gas mixture was switched from 40% oxygen to 40% oxygen and 7% carbon dioxide, sucking frequency decreased from 53 +/- 10 to 48 +/- 12 and from 54 +/- 12 to 40 +/- 19 sucks/min, respectively (p < 0.005). Frequency of swallowing also fell during the two feeding epochs on 7% carbon dioxide, from 45 +/- 15 to 40 +/- 15 and from 43 +/- 14 to 31 +/- 16 swallows/min (p < 0.003). Thus acute hypercapnea was accompanied by a decrease in rate of both sucking and swallowing during nutritive feeding. Increased ventilatory drive may directly inhibit nutritive feeding behavior in premature infants.
authors.affiliation: Department of Pediatrics, Case Western Reserve University School of Medicine, Cleveland, Ohio.
authors.forename: B J
authors.initials: BJ
authors.lastname: Timms
authors.forename: J M
authors.initials: JM
authors.lastname: DiFiore
authors.forename: R J
authors.initials: RJ
authors.lastname: Martin
authors.forename: M J
authors.initials: MJ
authors.lastname: Miller
mesh_terms: D001903:Bottle Feeding; D002245:Carbon Dioxide / Q000008:administration & dosage; D003679:Deglutition / Q000187:drug effects; D006801:Humans; D007223:Infant; D007231:Infant, Newborn; D007234:Infant, Premature / Q000502:physiology*; D010100:Oxygen / Q000008:administration & dosage; D012129:Respiratory Function Tests / Q000379:methods / Q000706:statistics & numerical data; D015656:Respiratory Mechanics / Q000187:drug effects; D013391:Sucking Behavior / Q000187:drug effects
chemical_list: D002245:Carbon Dioxide; D010100:Oxygen