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Hypercapnic ventilatory response in humans before, during, and after 23 days of low level CO2 exposure.
Aviat Space Environ Med. 1998 Apr; 69(4):391-6.AS

Abstract

Alterations in ventilation and the chemoreceptor response to CO2 during 23 d of 1.2% inspired CO2 were studied in four male subjects. Resting ventilation (VE), tidal volume (VT), respiratory frequency (fR), inspired and end tidal O2 and CO2 and the hypercapnic ventilatory response (HCVR) measured by CO2 rebreathing were measured once before entering the chamber, on days 2, 5, 11, and 22 of CO2 exposure, and one day after. Resting VE slightly increased (5%) on day 2 of exposure and significantly increased (22%) by day 5 followed by a progressive decrease to pre-chamber levels by day 22 and on the first day of recovery. Tidal volume and fR were not statistically different. During the exposure PetCO2 was significantly elevated with day 2 having the largest increase (19.6%). PetCO2 returned to normal within 24 h post exposure. The HCVR was characterized by the slope (SHCVR), intercept at zero ventilation (B), and the ventilation at a PCO2 = 60 mmHg (VE60). The SHCVR decreased (14%) on day 2, but was not significant; the SHCVR on the other exposure days were also not different. The SHCVR on the first recovery day significantly increased (37%). The HCVR B was shifted to the right on day 2 by 5.2 mmHg, then progressively returned to the pre-exposure position. On recovery the B significantly shifted 6.9 mmHg to the right of pre-exposure B. The VE60 decreased by approximately 32% and 16% on day 2 and 5, respectively, then returned within pre-exposure range for the remainder of the exposure and during recovery. During the early phase and one day after the exposure the HCVR was right shifted. One day after exposure chemoreceptor sensitivity to elevated CO2 was increased but, the B was right shifted resulting in a reduced HCVR below PCO2 of 60 mmHg and a greater HCVR above 60 mmHg.

Authors+Show Affiliations

Department of Medicine, University of California, San Diego, La Jolla, CA, USA.No affiliation info availableNo affiliation info availableNo affiliation info available

Pub Type(s)

Journal Article
Research Support, Non-U.S. Gov't
Research Support, U.S. Gov't, Non-P.H.S.

Language

eng

PubMed ID

9561287

Citation

Elliott, A R., et al. "Hypercapnic Ventilatory Response in Humans Before, During, and After 23 Days of Low Level CO2 Exposure." Aviation, Space, and Environmental Medicine, vol. 69, no. 4, 1998, pp. 391-6.
Elliott AR, Prisk GK, Schöllmann C, et al. Hypercapnic ventilatory response in humans before, during, and after 23 days of low level CO2 exposure. Aviat Space Environ Med. 1998;69(4):391-6.
Elliott, A. R., Prisk, G. K., Schöllmann, C., & Hoffmann, U. (1998). Hypercapnic ventilatory response in humans before, during, and after 23 days of low level CO2 exposure. Aviation, Space, and Environmental Medicine, 69(4), 391-6.
Elliott AR, et al. Hypercapnic Ventilatory Response in Humans Before, During, and After 23 Days of Low Level CO2 Exposure. Aviat Space Environ Med. 1998;69(4):391-6. PubMed PMID: 9561287.
* Article titles in AMA citation format should be in sentence-case
TY - JOUR T1 - Hypercapnic ventilatory response in humans before, during, and after 23 days of low level CO2 exposure. AU - Elliott,A R, AU - Prisk,G K, AU - Schöllmann,C, AU - Hoffmann,U, PY - 1998/4/30/pubmed PY - 1998/4/30/medline PY - 1998/4/30/entrez KW - NASA Discipline Cardiopulmonary KW - Non-NASA Center SP - 391 EP - 6 JF - Aviation, space, and environmental medicine JO - Aviat Space Environ Med VL - 69 IS - 4 N2 - Alterations in ventilation and the chemoreceptor response to CO2 during 23 d of 1.2% inspired CO2 were studied in four male subjects. Resting ventilation (VE), tidal volume (VT), respiratory frequency (fR), inspired and end tidal O2 and CO2 and the hypercapnic ventilatory response (HCVR) measured by CO2 rebreathing were measured once before entering the chamber, on days 2, 5, 11, and 22 of CO2 exposure, and one day after. Resting VE slightly increased (5%) on day 2 of exposure and significantly increased (22%) by day 5 followed by a progressive decrease to pre-chamber levels by day 22 and on the first day of recovery. Tidal volume and fR were not statistically different. During the exposure PetCO2 was significantly elevated with day 2 having the largest increase (19.6%). PetCO2 returned to normal within 24 h post exposure. The HCVR was characterized by the slope (SHCVR), intercept at zero ventilation (B), and the ventilation at a PCO2 = 60 mmHg (VE60). The SHCVR decreased (14%) on day 2, but was not significant; the SHCVR on the other exposure days were also not different. The SHCVR on the first recovery day significantly increased (37%). The HCVR B was shifted to the right on day 2 by 5.2 mmHg, then progressively returned to the pre-exposure position. On recovery the B significantly shifted 6.9 mmHg to the right of pre-exposure B. The VE60 decreased by approximately 32% and 16% on day 2 and 5, respectively, then returned within pre-exposure range for the remainder of the exposure and during recovery. During the early phase and one day after the exposure the HCVR was right shifted. One day after exposure chemoreceptor sensitivity to elevated CO2 was increased but, the B was right shifted resulting in a reduced HCVR below PCO2 of 60 mmHg and a greater HCVR above 60 mmHg. SN - 0095-6562 UR - https://www.unboundmedicine.com/medline/citation/9561287/Hypercapnic_ventilatory_response_in_humans_before_during_and_after_23_days_of_low_level_CO2_exposure_ DB - PRIME DP - Unbound Medicine ER -