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THE SHORT‐LATENCY RESPIRATORY RESPONSE TO SUDDEN WITHDRAWAL OF HYPERCAPNIA AND HYPOXIA IN MAN
Author(s) -
Drysdale D. B.,
Jensen J. I.,
Cunningham D. J. C.
Publication year - 1981
Publication title -
quarterly journal of experimental physiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.925
H-Index - 101
eISSN - 1469-445X
pISSN - 0144-8757
DOI - 10.1113/expphysiol.1981.sp002550
Subject(s) - hypercapnia , hypoxia (environmental) , medicine , respiratory system , cardiology , anesthesia , oxygen , chemistry , organic chemistry
Five healthy young male subjects were maintained in a state of mild asphyxia ( P A,CO2 ∼ 45 torr, 6·0 kPa, P A,O2 ∼ 50 torr, 6·6 kPa), i.e. with moderately strong drives from both arterial and intracranial chemoreceptors. V T , T T and T I were recorded and V and T E derived breath by breath. The arterial chemoreceptor component was briefly and abruptly reduced, perhaps silenced, by two separate procedures, each repeated twenty‐four times on each subject: B, removal of hypercapnia (two breaths hypoxia with P I,CO2 = 0 through a separate inspiratory line) and C, removal of asphyxia (two breaths O 2 ). In control tests, A, the maintenance mixture was replaced by an identical mixture, using an identical manipulation. For each subject means of B and C were compared with means of A and with each other. Quick reflex changes (first three breaths) in V , V T and T E in tests B were not appreciably different from those in tests C in any subject; changes in T I were minimal in all. Thus removal of only the hypercapnic component of the arterial chemoreflex drive appears to be as efficient as the removal of both components simultaneously.