Acute Cardiopulmonary and Muscle Oxygenation Responses to Normocapnic Hyperpnea Exercise in COPD.

Abstract

PURPOSE:

This study aimed to investigate cardiorespiratory responses and intercostal muscle oxygenation during normocapnic hyperpnea exercise in chronic obstructive pulmonary disease (COPD).

METHODS:

Twenty-two patients with COPD performed a cardiopulmonary cycling exercise test to assess peak oxygen consumption (V˙O2peak) and minute ventilation (V˙Epeak). They also performed a normocapnic hyperpnea exercise alone, at 50%-60% of V˙Epeak to exhaustion, using a respiratory device (Spirotiger) connected to a gas analyzer to monitor V˙O2, V˙E, and end-tidal CO2 partial pressure. Cardiac output, and intercostal and vastus lateralis muscle oxygenation were continuously measured during exercise using finger photoplethysmography and near-infrared spectroscopy, respectively. Arterial blood gases (arterial PCO2) and inspiratory capacity were obtained at rest and at the end of hyperpnea exercise.

RESULTS:

The hyperpnea exercise lasted 576 ± 277 s at a V˙E of 34.5 ± 12.1 L·min-1 (58% ± 6% of V˙Epeak), a respiratory rate of 22 ± 4 breaths per minute, and a tidal volume of 1.43 ± 0.43 L. From rest to the end of hyperpnea exercise, V˙O2 increased by 0.35 ± 0.16 L·min-1 (P < 0.001), whereas end-tidal CO2 partial pressure and arterial PCO2 decreased by ~2 mm Hg (P = 0.031) and ~5 mm Hg (P = 0.002, n = 13), respectively. Moreover, inspiratory capacity fell from 2.44 ± 0.84 L at rest to 1.96 ± 0.59 L (P = 0.002). During the same period, heart rate and cardiac output increased from 69 ± 12 bpm and 4.94 ± 1.15 L·min-1 at rest to 87 ± 17 bpm (P = 0.002) and 5.92 ± 1.58 L·min-1 (P = 0.007), respectively. During hyperpnea exercise, intercostal deoxyhemoglobin and total hemoglobin increased by 14.26% ± 13.72% (P = 0.001) and 8.69% ± 12.49% (P = 0.003) compared with their resting value. However, during the same period, vastus lateralis oxygenation remained stable (P > 0.05).

CONCLUSIONS:

In patients with COPD, normocapnic hyperpnea exercise provided a potent cardiorespiratory physiological stimulus, including dynamic hyperinflation, and increased intercostal deoxyhemoglobin consistent with enhanced requirement for muscle O2 extraction.

• Authors: Ferid Oueslati, Didier Saey, Félix-Antoine Vézina, Éric Nadreau, Mickaël Martin, François Maltais
• Journal: Medicine and science in sports and exercise (Med Sci Sports Exerc) Vol. 54 Issue 1 Pg. 47-56 (01 01 2022) ISSN: 1530-0315 [Electronic] United States
• PMID: 34334721 (Publication Type: Journal Article, Research Support, Non-U.S. Gov't)
• Copyright: Copyright © 2021 by the American College of Sports Medicine.

Topics

• Aged
• Exercise Test
• Exercise Therapy (methods)
• Female
• Humans
• Male
• Middle Aged
• Muscle, Skeletal (physiology)
• Oxygen Consumption (physiology)
• Pulmonary Disease, Chronic Obstructive (therapy)
• Respiratory Physiological Phenomena
• Respiratory Therapy (methods)