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Low-dose nebulized morphine does not improve exercise in interstitial lung disease
A O Harris-Eze1, G Sridhar, R E Clemens
1Division of Respiratory Medicine, University of Saskatchewan, Saskatoon, Canada.
Abstract:
Recent reports have suggested that low-dose nebulized morphine may improve exercise tolerance in patients with interstitial lung disease (ILD) by acting on peripheral opioid-sensitive pulmonary receptors. We therefore examined whether the administration of low-dose nebulized morphine would influence dyspnea or the breathing pattern during exercise of subjects with ILD and improve their exercise performance. Each of six subjects with ILD underwent three maximal incremental cycle ergometer tests, each test separated from the last by at least 3 d. Each exercise test was similar except that 30 min before exercise, the subjects received nebulized saline (control), morphine 2.5 mg, or morphine 5.0 mg, respectively, in double-blinded fashion. No significant differences were noted in exercise duration, maximal workload, or sense of dyspnea at the end of exercise in the control test and the tests with either morphine 2.5 mg or morphine 5.0 mg. Nor were significant differences noted in resting, submaximal, or end-exercise measurements of oxygen uptake (VO2), carbon dioxide output (VCO2), end-tidal CO2 (PETCO2), oxygen saturation (SaO2), minute ventilation (VI), respiratory frequency (f), tidal volume (VT), or heart rate (HR) in the three tests. Low-dose nebulized morphine did not alter the subjects' breathing pattern or affect the relationship between dyspnea and ventilation during exercise. No significant side effects were noted. The administration of low-dose nebulized morphine to subjects with ILD neither relieves their dyspnea during exercise nor improves their maximal exercise performance.
Insights
Low-dose nebulized morphine did not improve exercise tolerance or reduce breathlessness in patients with interstitial lung disease (ILD). This study found no significant benefits for exercise performance or respiratory measures in ILD patients receiving morphine via nebulizer.
Area of Science:
- Pulmonary Medicine
- Respiratory Physiology
Background:
- Interstitial lung disease (ILD) is characterized by impaired exercise tolerance and dyspnea.
- Peripheral opioid receptors in the lungs have been hypothesized to mediate benefits from nebulized morphine.
Purpose of the Study:
- To investigate the effect of low-dose nebulized morphine on exercise performance, dyspnea, and breathing patterns in patients with ILD.
- To determine if nebulized morphine can improve exercise capacity in individuals suffering from ILD.
Main Methods:
- A double-blind, placebo-controlled study involving six ILD patients.
- Subjects underwent maximal incremental cycle ergometer tests after receiving nebulized saline, morphine 2.5 mg, or morphine 5.0 mg.
- Measurements included exercise duration, workload, dyspnea, oxygen uptake, ventilation, and other respiratory parameters.
Main Results:
- No significant differences were observed in exercise duration, maximal workload, or end-exercise dyspnea between morphine and saline treatments.
- Nebulized morphine did not alter resting, submaximal, or end-exercise measurements of VO2, VCO2, PETCO2, SaO2, VI, f, VT, or HR.
- The breathing pattern and the relationship between dyspnea and ventilation during exercise remained unchanged.
Conclusions:
- Low-dose nebulized morphine does not relieve dyspnea during exercise in ILD patients.
- Nebulized morphine administration does not enhance maximal exercise performance in individuals with ILD.
- No significant side effects were noted with the use of low-dose nebulized morphine.