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Respir Physiol Neurobiol. 2016 Jul;228:25-9. doi: 10.1016/j.resp.2016.03.004. Epub 2016 Mar 7.

Inspiratory loading and limb blood flow in COPD: The modulating effects of resting lung hyperinflation.

Author information

1
Graduation Program in Pulmonology, School of Medicine, Federal University of Rio Grande do Sul (UFRGS), Brazil; Respiratory Division, Hospital de Clínicas de Porto Alegre (HCPA), Brazil. Electronic address: dberton@hcpa.edu.br.
2
Graduation Program in Pulmonology, School of Medicine, Federal University of Rio Grande do Sul (UFRGS), Brazil.
3
Graduation Program in Pulmonology, School of Medicine, Federal University of Rio Grande do Sul (UFRGS), Brazil; Respiratory Division, Hospital de Clínicas de Porto Alegre (HCPA), Brazil.
4
Exercise Pathophysiology Research Laboratory, Hospital de Clínicas de Porto Alegre (HCPA), Porto Alegre, Brazil.
5
Laboratory of Clinical Exercise Physiology (LACEP), Division of Respirology, Dept. of Medicine, Queen's University and Kingston General Hospital, Kingston, Canada.

Abstract

Inspiratory resistive loading (IRL) may have deleterious cardiocirculatory effects leading to poor peripheral perfusion in severely-hyperinflated patients with COPD. Nineteen patients (13 severely-hyperinflated with inspiratory capacity/total lung capacity ratio≤0.28) underwent calf blood flow (CBF) measurements by venous occlusion plethysmography at rest and during IRL at 60% maximal inspiratory pressure. Severely-hyperinflated patients had lower resting CBF and greater calf vascular resistance (CVR) than moderately-hyperinflated patients (p<0.05). All severely-hyperinflated patients had markedly reduced CBF (p=0.01). Opposite to our main hypothesis, however, IRL did not further reduce CBF in these patients (p>0.05). Conversely, it significantly decreased CBF and increased CVR in moderately-hyperinflated patients; in fact, end-trial CBF and CVR did not differ between the groups (p>0.05). In conclusion, marked impairments in resting appendicular blood flow in severely-hyperinflated patients with COPD were seen only after acute IRL in less hyperinflated patients. These findings set the stage for studies investigating the effects of lung deflation on peripheral hemodynamics in patients with severe hyperinflation.

KEYWORDS:

Chronic obstructive pulmonary disease; Inspiratory capacity; Regional blood flow; Respiratory function tests; Respiratory muscles

PMID:
26965088
DOI:
10.1016/j.resp.2016.03.004
[Indexed for MEDLINE]
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