Additive effects of non-invasive ventilation to hyperoxia on cerebral oxygenation in COPD patients with exercise-related O2 desaturation

Authors

  • Miguel K. Rodrigues,

    1. Pulmonary Function and Clinical Exercise Physiology Unit, Department of Medicine, Division of Respiratory Diseases, Federal University of Sao Paulo (UNIFESP), Sao Paulo, Brazil
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  • Mayron F. Oliveira,

    1. Pulmonary Function and Clinical Exercise Physiology Unit, Department of Medicine, Division of Respiratory Diseases, Federal University of Sao Paulo (UNIFESP), Sao Paulo, Brazil
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  • Aline Soares,

    1. Pulmonary Function and Clinical Exercise Physiology Unit, Department of Medicine, Division of Respiratory Diseases, Federal University of Sao Paulo (UNIFESP), Sao Paulo, Brazil
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  • Erika Treptow,

    1. Pulmonary Function and Clinical Exercise Physiology Unit, Department of Medicine, Division of Respiratory Diseases, Federal University of Sao Paulo (UNIFESP), Sao Paulo, Brazil
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  • J Alberto Neder

    Corresponding author
    1. Laboratory of Clinical Exercise Physiology, Department of Medicine, Division of Respiratory and Critical Care Medicine, Queen's University, Kingston, Canada
    • Pulmonary Function and Clinical Exercise Physiology Unit, Department of Medicine, Division of Respiratory Diseases, Federal University of Sao Paulo (UNIFESP), Sao Paulo, Brazil
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Correspondence

J Alberto Neder, Laboratory of Clinical Exercise Physiology (LACEP), Division of Respiratory and Critical Care Medicine, Queen's University, Richardson House, 102 Stuart Street, Kingston, ON KTL 2V6, Canada

E-mail: nederalb@gmail.com

Summary

Background

It is currently unknown whether potential haemodynamic improvements induced by non-invasive ventilation (NIV) would positively impact upon cerebral oxygenation (COx) in patients with moderate-to-severe chronic obstructive pulmonary disease (COPD).

Objective

To investigate the effects of NIV on exercise COx in COPD patients presenting with exercise-related O2 desaturation.

Methods

On a double-blind trial, 13 males (FEV= 48·8 ± 15·1% predicted) were randomly assigned to NIV (16 cmH2O IPS and 5 cmH2O PEEP) plus HOx (FiO=  0·4) or sham NIV (7 cmH2O IPS and 5 cmH2O PEEP to overcome breathing circuit resistance) plus HOx during ramp-incremental exercise performed on different days. Near-infrared spectroscopy and impedance cardiography assessed changes (Δ) in COx and cardiac output (QT), respectively.

Results

There were no significant between-intervention differences in peak work rate, ventilation and reported symptoms (P>0·05). Peripheral oxyhaemoglobin saturation remained above 98% throughout the tests. NIV + HOx was associated with larger increases in Δ COx, Δ QT and Δ stroke volume at maximal and submaximal exercise (P<0·05). Increases in the area under the curve (to an iso-work rate) of Δ COx under NIV + HOx were significantly (P<0·01) correlated with improvements in Δ QT (r = 0·82) and Δ stroke volume (r = 0·87). There was, however, no significant correlation between enhancement in these physiological responses with changes in peak work rate with NIV + HOx (P>0·05).

Conclusions

NIV added benefit to HOx in improving central haemodynamics and COx in O2 ‘desaturators’ with COPD. The clinical relevance of such beneficial effects on exercise tolerance, however, remains to be demonstrated.

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