Effects of Hypercapnia on Non-nutritive Swallowing in Newborn Lambs
The purpose of this study was to determine the effect of hypercapnia on non-nutritive swallowing (NNS) frequency and on NNS-breathing coordination in newborn lambs. Six lambs were chronically instrumented for recording electroencephalogram, eye movements, diaphragm and thyroarytenoid muscle activity, nasal airflow and electrocardiogram. Each lamb was placed in a Plexiglas chamber and exposed to a hypercapnic gas mixture (21% O2, 5% CO2). Polysomnographic recordings were conducted in non-sedated lambs using a custom-designed radiotelemetry system. Results show that hypercapnia increased NNS frequency in all three states of alertness (p < 0.0001 to 0.03), through a specific increase in ie-type NNS. Causal mechanisms and potential consequences of such observations on aspirations and apneas, as well as on swallowing maturation, will require further studies.
KeywordsRespiratory Control Nucleus Tractus Solitarius Nasal Airflow Plexiglas Chamber Free Nerve Ending
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- Oommen, M.P. (2004) Respiratory control during oral feeding. In : M.P. Oommen MP (Ed.), Respiratory Control and Disorders in the Newborn. Lung Biology in Health and Disease, Vol. 173. Marcel Dekker, New York, pp. 373–393.Google Scholar