Control of respiration in newborn babies. III. Developmental changes of respiratory depth and rate responses to CO2.
Thirteen healthy babies with PM ages varying between 32 and 43 weeks were investigated with regard to respiratory depth and rate changes on exposure to 4% CO2 in air. Two different types of responses were seen: above 37 weeks of postmenstrual age, the changes of depth and rate corresponded mostly to what is known in the adult human with a rate increase appearing only when the tidal volume had increased markedly ("Type A" responses). The preterm babies (i.e. under 37 weeks of PM age) responded mostly with a prompt rate increase without any preceding increase of the tidal volume ("Type B" response). The results indicate that the preterm baby in contrast to fullterm babies and adults may be dependent on the pulmonary vagal mechanoreceptor system for the regulation of the breathing in eupnoe.
D000005:Abdomen / Q000502:physiology; D000367:Age Factors; D002245:Carbon Dioxide / Q000494:pharmacology; D005260:Female; D006801:Humans; D007231:Infant, Newborn; D007234:Infant, Premature; D008297:Male; D011312:Pressure; D012119:Respiration / Q000187:drug effects; D013909:Thorax / Q000502:physiology
D002245:Carbon Dioxide