Differences between lung mechanics, respiratory and peripheral muscle
strength in former smokers and COPD individuals.
Abstract
Background: Reduced peripheral and respiratory muscle strength
correlates with impaired lung function in COPD, but whether
diminishement in peripheral and respiratory muscle strength correlates
with lung mechanis is unknown. Aims: To investigate whether spirometric
and respiratory and peripheral muscle strength correlates with small
airways obstruction evaluated by impulse oscillometry. Methods: Nighteen
COPD GOLD II and twenty former smokers’ individuals were evaluated for
lung function, lung mechanics, maximum inspiratory and expiratory
pressure and hand grip strength test. Results: COPD presented reduced
FEV1 and FEV1/FVC (p<0.001) compared to former smokers with no
changes in FVC. In COPD the FEV1 and FEV1/FVC showed a negative
correlation with BMI (P<0.05, R=-0.56 and -0.43,
respectively). The total resistance of respiratory system and small
airway resistance were reduced in the COPD compared to former smoke
group. The COPD individuals showed a negative moderate correlation
between FEV1 and impedance (R=-0,664; P<0.01); airway
resistance (R=-0,593, P<0.05) and peripheral airway resistance
(R=-0,547, P<0.05). The negative correlation was low in COPD
individuals for reactance (R=-0,434, P<0.05) and proximal
airway resistance (R=-0,480, P<0.05). These correlations were
not found in the former smoke group. Hand grip strength measured in the
right arm showed a moderate negative correlation with the maximal
inspiratory pressure (R=-0,539, P<0.05) in COPD individuals.
There was no correlation between PIMax and PEMax with none of the
spirometric or oscillometric parameters (p>0.05) in COPD or
former smokers’ individuals. Conclusions: Lung mechanics correlate with
spirometric parameters in COPD patients but not with respiratory and
peripheral muscle strength.