The influence of thoracic gas compression and airflow density dependence on the assessment of pulmonary function at high altitude
- PMID: 29595881
- PMCID: PMC5875542
- DOI: 10.14814/phy2.13576
The influence of thoracic gas compression and airflow density dependence on the assessment of pulmonary function at high altitude
Abstract
The purpose of this report was to illustrate how thoracic gas compression (TGC) artifact, and differences in air density, may together conflate the interpretation of changes in the forced expiratory flows (FEFs) at high altitude (>2400 m). Twenty-four adults (10 women; 44 ± 15 year) with normal baseline pulmonary function (>90% predicted) completed a 12-day sojourn at Mt. Kilimanjaro. Participants were assessed at Moshi (Day 0, 853 m) and at Barafu Camp (Day 9, 4837 m). Typical maximal expiratory flow-volume (MEFV) curves were obtained in accordance with ATS/ERS guidelines, and were either: (1) left unadjusted; (2) adjusted for TGC by constructing a "maximal perimeter" MEFV curve; or (3) adjusted for both TGC and differences in air density between altitudes. Forced vital capacity (FVC) was lower at Barafu compared with Moshi camp (5.19 ± 1.29 L vs. 5.40 ± 1.45 L, P < 0.05). Unadjusted data indicated no difference in the mid-expiratory flows (FEF25-75% ) between altitudes (∆ + 0.03 ± 0.53 L sec-1 ; ∆ + 1.2 ± 11.9%). Conversely, TGC-adjusted data revealed that FEF25-75% was significantly improved by sojourning at high altitude (∆ + 0.58 ± 0.78 L sec-1 ; ∆ + 12.9 ± 16.5%, P < 0.05). Finally, when data were adjusted for TGC and air density, FEFs were "less than expected" due to the lower air density at Barafu compared with Moshi camp (∆-0.54 ± 0.68 L sec-1 ; ∆-10.9 ± 13.0%, P < 0.05), indicating a mild obstructive defect had developed on ascent to high altitude. These findings clearly demonstrate the influence that TGC artifact, and differences in air density, bear on flow-volume data; consequently, it is imperative that future investigators adjust for, or at least acknowledge, these confounding factors when comparing FEFs between altitudes.
Keywords: Airflow density dependence; forced expiratory flows; high altitude; thoracic gas compression.
© 2018 The Authors. Physiological Reports published by Wiley Periodicals, Inc. on behalf of The Physiological Society and the American Physiological Society.
Figures
![Figure 1](https://www.ncbi.nlm.nih.gov/pmc/articles/instance/5875542/bin/PHY2-6-e13576-g001.gif)
![Figure 2](https://www.ncbi.nlm.nih.gov/pmc/articles/instance/5875542/bin/PHY2-6-e13576-g002.gif)
![Figure 3](https://www.ncbi.nlm.nih.gov/pmc/articles/instance/5875542/bin/PHY2-6-e13576-g003.gif)
![Figure 4](https://www.ncbi.nlm.nih.gov/pmc/articles/instance/5875542/bin/PHY2-6-e13576-g004.gif)
Similar articles
-
Thoracic gas compression during forced expiration is greater in men than women.Physiol Rep. 2020 Mar;8(6):e14404. doi: 10.14814/phy2.14404. Physiol Rep. 2020. PMID: 32207254 Free PMC article.
-
Effect of thoracic gas compression and bronchodilation on the assessment of expiratory flow limitation during exercise in healthy humans.Respir Physiol Neurobiol. 2010 Mar 31;170(3):279-86. doi: 10.1016/j.resp.2010.01.017. Epub 2010 Feb 4. Respir Physiol Neurobiol. 2010. PMID: 20138157
-
Effects of lung volume and thoracic gas compression on maximal and partial flow-volume curves.Eur Respir J. 1996 Oct;9(10):2168-73. doi: 10.1183/09031936.96.09102168. Eur Respir J. 1996. PMID: 8902484
-
Respiratory function at different altitudes.Respiration. 1997;64(6):416-21. doi: 10.1159/000196717. Respiration. 1997. PMID: 9383816 Review.
-
Spirometry and respiratory muscle function during ascent to higher altitudes.Lung. 2007 Mar-Apr;185(2):113-21. doi: 10.1007/s00408-006-0108-y. Epub 2007 Mar 28. Lung. 2007. PMID: 17393241 Review.
Cited by
-
Clinical characteristics and predictors of pulmonary hypertension in chronic obstructive pulmonary disease at different altitudes.BMC Pulm Med. 2023 Apr 18;23(1):127. doi: 10.1186/s12890-023-02405-8. BMC Pulm Med. 2023. PMID: 37072815 Free PMC article.
-
Expiratory Peak Flow and Minute Ventilation Are Significantly Increased at High Altitude versus Simulated Altitude in Normobaria.Life (Basel). 2022 Feb 17;12(2):306. doi: 10.3390/life12020306. Life (Basel). 2022. PMID: 35207593 Free PMC article.
-
Thoracic gas compression during forced expiration is greater in men than women.Physiol Rep. 2020 Mar;8(6):e14404. doi: 10.14814/phy2.14404. Physiol Rep. 2020. PMID: 32207254 Free PMC article.
References
-
- Basu, C. K. , Banerjee P. K., Selvamurthy W., Sarybaev A., and Mirrakhimov M. M.. 2007. Acclimatization to high altitude in the Tien Shan: a comparative study of Indians and Kyrgyzis. Wilderness Environ. Med. 18:106–110. - PubMed
-
- Bert, P . 1878. La pression barométrique: recherches de physiologie expérimentale. Masson, Paris.
-
- Bouzat, P. , Walther G., Rupp T., Doucende G., Payen J. F., Levy P., et al. 2013. Time course of asymptomatic interstitial pulmonary oedema at high altitude. Respir. Physiol. Neurobiol. 186:16–21. - PubMed
-
- Coates, G. , Gray G., Mansell A., Nahmias C., Powles A., Sutton J., et al. 1979. Changes in lung volume, lung density, and distribution of ventilation during hypobaric decompression. J Appl Physiol Respir Environ Exerc Physiol 46:752–755. - PubMed
Publication types
MeSH terms
LinkOut - more resources
Full Text Sources
Other Literature Sources