The characteristics and frequency of augmented breaths during CO2-induced hyperpnoea of newborn infants
| Autor: | D J Henderson-Smart, G Cohen |
|---|---|
| Rok vydání: | 1996 |
| Předmět: |
medicine.medical_specialty
Physiology Sleep REM Hypercapnia Internal medicine Tidal Volume Humans Medicine Respiratory system Tidal volume Retrospective Studies Eupnea Inhalation business.industry Respiration Infant Newborn Carbon Dioxide Surgery Control of respiration Respiratory Mechanics Cardiology Reflex Pulmonary Ventilation business Full term infants Research Article |
| Zdroj: | The Journal of Physiology. 490:551-557 |
| ISSN: | 0022-3751 |
| DOI: | 10.1113/jphysiol.1996.sp021166 |
| Popis: | 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. |
| Databáze: | OpenAIRE |
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