Abstract
In healthy man, the central chemosensitivity to CO2 was studied after depression of the arterial chemoreflex drive by inhalation of pure oxygen. The effectiveness of the functional decrease of arterial chemoreceptor function was assessed by the delayed hyperventilation which followed transient inhalation of hypercapnic gas mixtures for 3 or 5 breaths in hyperoxic conditions. In such a case the first significant increase in tidal volume (VT) occurred 13.9 +/- 3.2 (SE) sec later than the early change in this variable measured in normoxic conditions. The stimulus strength was estimated by the change in CO2 partial pressure in end-tidal alveolar gas (delta PETCO2). The central chemosensitivity (SCO2), defined as the ratio between change in ventilation (delta V) and delta PETCO2, was assessed either by transient inhalation of gas mixtures containing 5 to 8% CO2 in pure O2 ("varying transients") or by progressive hypercapnia (rebreathing in pure O2). In both cases, the first significant change in ventilation was due to an increase in VT, but, for a given delta PETCO2, VT changes were higher during rebreathing than after transient hypercapnia; (2) The respiratory frequency (fR) was progressively enhanced during rebreathing (shortening...Continue Reading
References
Sep 1, 1975·Respiration Physiology·S Lahiri, R G DeLaney
Feb 1, 1978·Chest·N H EdelmanT V Santiago
Jul 1, 1976·Chest·J A Dempsey
Jun 1, 1971·Respiration Physiology·R S Fitzgerald, D C Parks
Nov 1, 1974·Acta Physiologica Scandinavica·G W BradleyB Roos
Dec 1, 1973·Journal of Applied Physiology·R Gelfand, C J Lambertsen
Feb 1, 1974·Respiration Physiology·J P MillerJ M Young
Apr 1, 1972·Respiration Physiology·R LefrançoisJ Leroy
Apr 1, 1972·The Journal of Physiology·F J Clark, C von Euler
May 1, 1968·Respiration Physiology·R S FitzgeraldR E Dutton
Sep 1, 1965·Journal of Applied Physiology·P DejoursM Dicharry
Jul 1, 1967·Journal of Applied Physiology·D J Read, J Leigh
Jan 1, 1958·Pflügers Archiv : European journal of physiology·H H LOESCHCKEK H GERTZ
May 1, 1961·Journal of Applied Physiology·C J LAMBERTSENR GELFAND
Jul 1, 1962·Physiological Reviews·P DEJOURS
Mar 1, 1964·Journal of Applied Physiology·H H BENDIXENJ MEAD
Mar 1, 1965·The American Journal of Physiology·J R PAPPENHEIMERD HELD