Maximal respiratory pressures: Measurements at functional residual capacity in individuals with different health conditions using a digital manometer

Bruna M F Silveira; Henrique R Martins; Giane A Ribeiro-Samora; Luciano F Oliveira; Eliane V Mancuzo; Marcelo Velloso; Verônica F Parreira

doi:10.1016/j.bjpt.2023.100529

Maximal respiratory pressures: Measurements at functional residual capacity in individuals with different health conditions using a digital manometer

Braz J Phys Ther. 2023 Jul-Aug;27(4):100529. doi: 10.1016/j.bjpt.2023.100529. Epub 2023 Aug 1.

Authors

Bruna M F Silveira¹, Henrique R Martins², Giane A Ribeiro-Samora¹, Luciano F Oliveira³, Eliane V Mancuzo⁴, Marcelo Velloso³, Verônica F Parreira⁵

Affiliations

¹ Rehabilitation Sciences Program, Universidade Federal de Minas Gerais, Belo Horizonte, Minas Gerais, Brazil.
² Electrical Engineering Program, Universidade Federal de Minas Gerais, Belo Horizonte, Minas Gerais, Brazil.
³ Department of Physical Therapy, Universidade Federal de Minas Gerais, Belo Horizonte, Minas Gerais, Brazil.
⁴ Department of Internal Medicine, Universidade Federal de Minas Gerais, Belo Horizonte, Minas Gerais, Brazil; Lung function Laboratory, Universidade Federal de Minas Gerais, Belo Horizonte, Minas Gerais, Brazil.
⁵ Department of Physical Therapy, Universidade Federal de Minas Gerais, Belo Horizonte, Minas Gerais, Brazil. Electronic address: veronica.parreira@pesquisador.cnpq.br.

Abstract

Background: Measuring maximal respiratory pressure is a widely used method of investigating the strength of inspiratory and expiratory muscles.

Objectives: To compare inspiratory pressures obtained at functional residual capacity (FRC) with measures at residual volume (RV), and expiratory pressures obtained at FRC with measures at total lung capacity (TLC) in individuals with different health conditions: post-COVID-19, COPD, idiopathic pulmonary fibrosis (IPF), heart failure (CHF), and stroke; and to compare the mean differences between measurements at FRC and RV/TLC among the groups.

Methods: Inspiratory and expiratory pressures were obtained randomly at different lung volumes. Mixed factorial analysis of covariance with repeated measures was used to compare measurements at different lung volumes within and among groups.

Results: Seventy-five individuals were included in the final analyses (15 individuals with each health condition). Maximal inspiratory pressures at FRC were lower than RV [mean difference (95% CI): 11.3 (5.8, 16.8); 8.4 (2.3, 14.5); 11.1 (5.5, 16.7); 12.8 (7.1, 18.4); 8.0 (2.6, 13.4) for COVID-19, COPD, IPF, CHF, and stroke, respectively] and maximal expiratory pressures at FRC were lower than TLC [mean difference (95% CI): 51.9 (37.4, 55.5); 60.9 (44.2, 77.7); 62.9 (48.1, 77.8); 58.0 (43.9, 73.8); 57.2 (42.9, 71.6) for COVID-19, COPD, IPF, CHF, and stroke, respectively]. All mean differences were similar among groups.

Conclusion: Although inspiratory and expiratory pressures at FRC were lower than measures obtained at RV/TLC for the five groups of health conditions, the mean differences between measurements at different lung volumes were similar among groups, which raises the discussion about the influence of the viscoelastic properties of the lungs on maximal respiratory pressure.

Keywords: Dyspnea; Functional residual capacity; Heart diseases; Lung diseases; Physical therapy; Respiratory muscles.

MeSH terms

COVID-19*
Functional Residual Capacity
Humans
Lung
Maximal Respiratory Pressures
Pulmonary Disease, Chronic Obstructive*
Stroke*