Abstract
We examined the relationship between the initiation of breathing at birth and the timing of delivery of the chest in a group of 13 lambs undergoing spontaneous unassisted delivery at term. In 8 of 11 lambs with a diaphragm electromyogram or intrapleural pressure signal the first breath occured chest delivery. The first breath was always followed by a period of irregular and often powerful inspiratory effeorts. Some of these inspirations were followed by a forceful expiration. A regular respiratory rhythm never developed until the chest had delivered, suggesting that chest expansion is essential for the establishment of rhythm. Although PaO2 increased rapidly after birth, pHa declined and reached its lowest level approximately 20 minutes postnatally suggesting that considerable anaerobic metabolism occurs in the face of adequate arterial oxygenation. The level of respiratory activity in the first 30 min following birth did not appear to be related to arterial PO2, PCO2 or pH. Neither the appearance of the EMG activity of the first breath, nor blood samples taken from 2 lambs simultaneously with the first breath, suggested that the first breath was a gasp initiated by asphyxial blood gases. Our results therefore do not support the current hypothesis that the first breath is a gasp initiated by asphyxia accompanying delivery.
| Original language | English |
|---|---|
| Pages (from-to) | 251-265 |
| Number of pages | 15 |
| Journal | Respiration Physiology |
| Volume | 82 |
| Issue number | 2 |
| DOIs | |
| Publication status | Published - 1 Jan 1990 |
Keywords
- Animal
- at birth
- Birth
- Blood gases
- Control of breathing
- Diaphragm
- EMG at birth
- lamb
- onset of respiration
- pH
Cite this
}
Breathing at birth and the associated blood gas an pH changes in the lamb. / Berger, P. J.; Horne, R. S.C.; Soust, M.; Walker, A. M.; Maloney, J. E.
In: Respiration Physiology, Vol. 82, No. 2, 01.01.1990, p. 251-265.Research output: Contribution to journal › Article › Research › peer-review
TY - JOUR
T1 - Breathing at birth and the associated blood gas an pH changes in the lamb
AU - Berger, P. J.
AU - Horne, R. S.C.
AU - Soust, M.
AU - Walker, A. M.
AU - Maloney, J. E.
PY - 1990/1/1
Y1 - 1990/1/1
N2 - We examined the relationship between the initiation of breathing at birth and the timing of delivery of the chest in a group of 13 lambs undergoing spontaneous unassisted delivery at term. In 8 of 11 lambs with a diaphragm electromyogram or intrapleural pressure signal the first breath occured chest delivery. The first breath was always followed by a period of irregular and often powerful inspiratory effeorts. Some of these inspirations were followed by a forceful expiration. A regular respiratory rhythm never developed until the chest had delivered, suggesting that chest expansion is essential for the establishment of rhythm. Although PaO2 increased rapidly after birth, pHa declined and reached its lowest level approximately 20 minutes postnatally suggesting that considerable anaerobic metabolism occurs in the face of adequate arterial oxygenation. The level of respiratory activity in the first 30 min following birth did not appear to be related to arterial PO2, PCO2 or pH. Neither the appearance of the EMG activity of the first breath, nor blood samples taken from 2 lambs simultaneously with the first breath, suggested that the first breath was a gasp initiated by asphyxial blood gases. Our results therefore do not support the current hypothesis that the first breath is a gasp initiated by asphyxia accompanying delivery.
AB - We examined the relationship between the initiation of breathing at birth and the timing of delivery of the chest in a group of 13 lambs undergoing spontaneous unassisted delivery at term. In 8 of 11 lambs with a diaphragm electromyogram or intrapleural pressure signal the first breath occured chest delivery. The first breath was always followed by a period of irregular and often powerful inspiratory effeorts. Some of these inspirations were followed by a forceful expiration. A regular respiratory rhythm never developed until the chest had delivered, suggesting that chest expansion is essential for the establishment of rhythm. Although PaO2 increased rapidly after birth, pHa declined and reached its lowest level approximately 20 minutes postnatally suggesting that considerable anaerobic metabolism occurs in the face of adequate arterial oxygenation. The level of respiratory activity in the first 30 min following birth did not appear to be related to arterial PO2, PCO2 or pH. Neither the appearance of the EMG activity of the first breath, nor blood samples taken from 2 lambs simultaneously with the first breath, suggested that the first breath was a gasp initiated by asphyxial blood gases. Our results therefore do not support the current hypothesis that the first breath is a gasp initiated by asphyxia accompanying delivery.
KW - Animal
KW - at birth
KW - Birth
KW - Blood gases
KW - Control of breathing
KW - Diaphragm
KW - EMG at birth
KW - lamb
KW - onset of respiration
KW - pH
UR - http://www.scopus.com/inward/record.url?scp=0025026481&partnerID=8YFLogxK
U2 - 10.1016/0034-5687(90)90039-2
DO - 10.1016/0034-5687(90)90039-2
M3 - Article
VL - 82
SP - 251
EP - 265
JO - Respiration Physiology
JF - Respiration Physiology
SN - 0034-5687
IS - 2
ER -