Document Detail


The characteristics and frequency of augmented breaths during CO2-induced hyperpnoea of newborn infants.
MedLine Citation:
PMID:  8821151     Owner:  NLM     Status:  MEDLINE    
Abstract/OtherAbstract:
1. Hypercapnic ventilatory responses of thirty-five full term infants aged 1-7 days were evaluated, and the characteristics and incidence of augmented breaths were determined. 2. According to the inspiratory airflow profile and tidal volume (VT), augmented breaths were categorized as 'type A' (biphasic, VT > or = 2 x control VT), or 'type M' (multiphasic, VT < 2 x control VT). 3. Steady-state inhalation of 2-4% CO2 resulted in a 3-fold increase in the frequency of augmented breaths after 8 min; 80 s rebreathing a mixture containing 5-6% CO2 resulted in a 20-fold increase in the frequency of these breaths. 4. During eupnoea, 85% of spontaneously occurring augmented breaths were type A. With increasing respiratory drive, there was a disproportionate increase in type M compared with type A breaths: after 80 s rebreathing, 86% of augmented breaths were type M and only 14% were type A. 5. These findings indicate that the hypercapnic hyperpnoea facilitates an inspiration-augmenting reflex in newborn infants. The significance of type M breaths is unclear; they appear to be characteristic of the newborn, and may represent the response of an immature respiratory system to load.
Authors:
G Cohen; D J Henderson-Smart
Publication Detail:
Type:  Journal Article    
Journal Detail:
Title:  The Journal of physiology     Volume:  490 ( Pt 2)     ISSN:  0022-3751     ISO Abbreviation:  J. Physiol. (Lond.)     Publication Date:  1996 Jan 
Date Detail:
Created Date:  1996-11-06     Completed Date:  1996-11-06     Revised Date:  2009-11-18    
Medline Journal Info:
Nlm Unique ID:  0266262     Medline TA:  J Physiol     Country:  ENGLAND    
Other Details:
Languages:  eng     Pagination:  551-7     Citation Subset:  IM    
Affiliation:
Department of Perinatal Medicine, King George V Hospital, Camperdown, NSW, Australia.
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MeSH Terms
Descriptor/Qualifier:
Carbon Dioxide / diagnostic use*
Humans
Hypercapnia
Infant, Newborn / physiology*
Pulmonary Ventilation / physiology
Respiration / physiology*
Respiratory Mechanics / physiology
Retrospective Studies
Sleep, REM / physiology
Tidal Volume / physiology
Chemical
Reg. No./Substance:
124-38-9/Carbon Dioxide
Comments/Corrections

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