Effect of Feeding on the Chemical Control of Breathing in the Newborn Infant

Abstract

Summawflowmeter was used to record flow. tidal volume. end-tidal CO?To examine the influence of feeding on the chemical control of breathing in neonates, we studied the ventilatory response to 3% CO2 in air in nine bottle fed (BOT) and eight breast fed (BR) term infants during feeding while the infants were alert: Control responses were obtained either before or after feeding. VE, respiratory frequency, tidal volume, inspiratory time, expiratory time, and sum of inspiratory and expiratory time, VT/Ti, Ti/TtOt, PACOz and slope (S) of CO2 response (liter/min/kg/mmHg) were determined. During 3% C02 while resting BR had a lower VE, VT, VT/ Ti than BOT and S in BR was 40% of BOT (P < 0.05). During feeding and CO2 when compared to resting and COz there was no difference in either BR or BOT in VT/T~ but Ti/Tbt decreased in both groups. During feeding, S in BOT was reduced from 0.049 * 0.012 (mean f S.E.) to 0.013 f 0.002 (74% reduction) and in BR from 0.020 f 0.002 to 0.009 f 0.002 (55%). Thus, behavioral activity (either BR or BOT) markedly depresses the ventilatory response to chemical stimuli (Cod. This modification is primarily related to changes in "effective" respiratory timing (Ti/TtOt) rather than mean inspiratory flow (VT/Ti). SpeculationThis is the first demonstration in the newborn infant that behavioral activity (feeding) can override the usual ventilatory control mechanisms. Tbe precise mechanism is unknown and requires further study.Breathing is controlled by two functionally integrated elements: the behavioral (voluntary) control system, which originates in the forebrain, is involved in activities such as phonation; and the metabolic (automatic) respiratory control system, centered in the brain stem (2, 12). Studies in healthy adult subjects have shown that during normal speech there is a marked disruption of the ventilatory response to C 0 2 (3, 15), suggesting that during phonation there is a relaxation or overriding of metabolic respiratory control. The influence of behavioral activity on the chemical control of breathing in neonates has not been studied. We designed this study, therefore, to examine the interaction of the metabolic and behavioral respiratory control systems, by comparing the ventilatory response to COz in bottle fed and breast fed infants while resting and during feeding. MATERIALS AND METHODSWe studied nine bottle fed healthy term infants (BOT): birth weight (mean * S.E.) 3.15 f 0.15 kg; gestational age 39.2 f 1.0 wk; postnatal age 6.4 * 2.4 days; and 8 breast fed healthy term infants (BR); birth weight 3.35 f 0.14 kg; gestational age 39.8 * 0.3 wk; postnatal age 4.2 * 0.7 days. There were five males and four females in the BOT group, and five males and three females in the BR group. The study was explained to the parents of each subject and informed consent obtained.A nosepiece with a constant background flow and a screen and 0 2 concentrations, according tb methods described in detaii previously (18,19), and recording was done with a Gould Brush 480 Recorder. The ventilatory re...

The Relationship between Rhythmic Swallowing and Breathing during Suckle Feeding in Term Neonates

“…Breast-and bottle-feeding may have different effects: Mathew and Bhatia (3) reported that breathing was reduced in bottle-fed but not in breast-fed infants and suggested that the difference is caused by the bottle producing faster flow, making the infant spend more time swallowing. Inspiratory time was unchanged in breast-feeding but fell during bottle-feeding (12,14). This could reduce minute ventilation because less time is available for air intake.…”

Sucking and swallowing in infants and diagnostic tools

“…As infants commonly swallow as often as 60 times a minute, and there is an airway closure averaging 530 ms associated with swallows, this means that during the initial period of continuous sucking, the airway closure lasts up to 30 s a minute. 24 This makes it important for respiration to be exquisitely coordinated with swallowing.…”

Oxygen Transport and Utilization during Feeding in the Young Lamb

“…Subsequently, with a switch to the intermittent phase of feeding, sucking continues apparently uninterrupted, although the frequency of swallowing is reduced and normal minute ventilation is resumed. While it is known that feeding markedly alters respiratory control and function (Durand, Leahy, MacCallum, Cates, Rigatto & Chernick, 1981;Shivpuri et al 1983), and it is known that many factors interact to control food intake and the duration of a meal (Woods, Taborsky & Porte, 1986), those factors which interrupt sucking, re-establish breathing and lead to the cyclic pattern of sucking and non-sucking observed within a feeding epoch before satiety is achieved are not completely understood. A combination of peripheral and central chemoreceptor inputs probably play key roles.…”