16890
document
The reversibility of increased airways resistance in chronic heart failure measured by impulse oscillometry . BACKGROUND Patients with chronic heart failure complain of breathlessness and fatigue on exercise . Airways resistance is increased and lung compliance is reduced in chronic heart failure patients . The aim of this study was to determine whether the pulmonary abnormalities are reversible and whether any improvements lead to changes to exercise capacity or symptoms . METHODS Twelve patients with stable chronic heart failure and 10 matched controls underwent repeated assessment of airways resistance using impulse oscillometry and peak exercise testing with metabolic gas exchange after receiving nebulized saline as placebo or combined salbutamol and ipratropium bromide in a double-blind crossover randomized fashion . RESULTS Patients had lower peak oxygen consumption and a steeper slope relating ventilation to carbon dioxide production than controls . Bronchodilators reduced peripheral airways resistance in patients ( 0.53 versus 0.38 , P < .02 ) and controls ( 0.21 versus 0.19 , P < .005 ) and increased measures of compliance in both groups . There was no effect on the peak oxygen consumption , exercise time , ventilation to carbon dioxide slope , or anaerobic threshold . There was an increase in peak tidal volume ( VT ) in both groups but this did not lead to an increase in peak ventilation . The slope relating symptoms to ventilation ( ie , Borg/VE ) was significantly reduced in the patients after bronchodilators ( 17 % +/-8 % , P < .05 ) . The relationship between the improvement in VT and reduction in gradient of the Borg/VE slope was significant ( r=.40 , P < .05 ) . CONCLUSIONS Nebulized bronchodilators improve airways resistance , lung reactance , and peak tidal volume during exercise in chronic heart failure but do not increase peak exercise capacity . They do , however , reduce the symptom of breathlessness .
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Intervention_Physical
oscillometry and peak exercise testing with metabolic gas exchange
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Intervention_Control
nebulized saline as placebo
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Intervention_Pharmacological
combined salbutamol
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Intervention_Pharmacological
ipratropium bromide
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Outcome_Physical
peak oxygen consumption
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Outcome_Physical
peak oxygen consumption , exercise time
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Outcome_Physical
ventilation to carbon dioxide slope
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Outcome_Physical
anaerobic threshold
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Outcome_Physical
peak tidal volume ( VT )
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Outcome_Physical
peak ventilation
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Outcome_Physical
ventilation
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Outcome_Physical
Borg/VE slope
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Outcome_Physical
airways resistance , lung reactance
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Outcome_Physical
peak tidal volume
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Outcome_Physical
symptom of breathlessness
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Participant_Condition
chronic heart failure
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Participant_Sample-size
Twelve patients
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Participant_Condition
stable chronic heart failure
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Participant_Sample-size
10 matched controls