Hypercapnic and Hypoxic Ventilatory Responses during Growth

Yoshiyuki Honda, Yoshio Ohyabu, Midori Sato, Hidenori Masuyama, Yoshitake Nishibayashi, Ryoko Maruyama, Yukio Tanaka, Ikuo Nakajo, Hideham Shirase, Kazutaka Hayashida

Research output: Contribution to journalArticlepeer-review

4 Citations (Scopus)

Abstract

Cross-sectional studies on hypercapnic and hypoxic ventilatory chemosensitivities were performed in 71 children ranging in age from 7 to 18yrs. The subjects were classified into 6 successive 2-year age groups. CO2 ventilatory response was measured by rebreathing 5% CO2 in O2, a slight modification of the method originally proposed by Read. The results were evaluated when the CO2-ventilation feedback control system was supposed to have attained the open-loop condition. Hypoxic ventilatory response was measured by the isocapnic progressive hypoxia test. To obtain good reproducibility in the ventilatory response, end-tidal PCO2 was maintained at 5 mmHg higher than the resting condition throughout the test. Normalized ventilatory responses to CO2 by body surface area (S/BSA) progressively decreased from the 7-8 through the 11-12 yr groups, and then tended to decrease further in a more gradual manner with increasing age. This trend was very similar to the normalized CO2 output (VCO2/BSA), but did not parallel so closely the normalized O2 intake (VCO2/BSA). When ventilatory and metabolic parameters were normalized by body weight (BW), or the lean body mass (LBM), qualitatively similar relationships between CO2 sensitivities and metabolic parameters were also obtained. Contrary to the hypercapnic response, hypoxic ventilatory chemosensitivities were not significantly different among the 6 different age groups. We concluded that normalized hypercapnic chemosensitivity decreased during growth and corresponded well with decreased CO2 output per unit body mass.

Original languageEnglish
Pages (from-to)177-187
Number of pages11
JournalThe Japanese journal of physiology
Volume36
Issue number1
DOIs
Publication statusPublished - 1986

Keywords

  • body surface area
  • body weight
  • hypercapnic ventialtory response
  • hypoxic ventilatory response
  • lean body mass

ASJC Scopus subject areas

  • Physiology

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