Journal of Clinical Medicine (Aug 2020)

Correlation of Arterial CO<sub>2</sub> and Respiratory Impedance Values among Subjects with COPD

  • Tomoki Uno,
  • Tetsuya Homma,
  • Masahiko Shigemura,
  • Yosuke Fukuda,
  • Tomoyuki Kimura,
  • Chihiro Onitsuka,
  • Tomoko Kawahara,
  • Hiroki Sato,
  • Kaho Akimoto,
  • Hiromitsu Suganuma,
  • Ayaka Kashima,
  • Shigenori Yamamoto,
  • Takaya Ebato,
  • Tomohiro Matsunaga,
  • Keisuke Kaneko,
  • Hatsuko Mikuni,
  • Haruna Sato,
  • Yoshitaka Uchida,
  • Akiko Fujiwara,
  • Naota Kuwahara,
  • Ryo Manabe,
  • Hitomi Ida,
  • Kuniaki Hirai,
  • Yoshito Miyata,
  • Megumi Jinno,
  • Shin Ohta,
  • Yasunari Kishino,
  • Hideki Inoue,
  • Mayumi Yamamoto,
  • Yoshio Watanabe,
  • Sojiro Kusumoto,
  • Koichi Ando,
  • Shintaro Suzuki,
  • Akihiko Tanaka,
  • Tohru Ohmori,
  • Hironori Sagara

DOI
https://doi.org/10.3390/jcm9092819
Journal volume & issue
Vol. 9, no. 9
p. 2819

Abstract

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Chronic obstructive pulmonary disease (COPD) is a respiratory illness characterized by airflow limitation and chronic respiratory symptoms with a global prevalence estimated to be more than 10% in 2010 and still on the rise. Furthermore, hypercapnic subject COPD leads to an increased risk of mortality, morbidity, and poor QoL (quality of life) than normocapnic subjects. Series of studies showed the usefulness of the forced oscillation technique (FOT) to measure small airway closure. Traditional findings suggested that hypercapnia may not be the main treating targets, but recent findings suggested that blood stream CO2 may lead to a worse outcome. This study aimed to seek the relationship between CO2 and small airway closure by using FOT. Subjects with COPD (n = 124; hypercapnia 22 and normocapnia 102) were analyzed for all pulmonary function values, FOT values, and arterial blood gas analysis. Student’s t-test, Spearman rank correlation, and multi linear regression analysis were used to analyze the data. COPD subjects with hypercapnia showed a significant increase in R5, R20, Fres, and ALX values, and a greater decrease in X5 value than normocapnic patients. Also, multiple linear regression analysis showed R5 was associated with hypercapnia. Hypercapnia may account for airway closure among subjects with COPD and this result suggests treating hypercapnia may lead to better outcomes for such a subject group.

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