The Effects of Low-Dose Morphine on Externally Applied Inspiratory Resistive Load Magnitude Perception in Chronic Obstructive Pulmonary Disease
Date
2025
Authors
Altree, T.J.
Pinczel, A.
Toson, B.
Loffler, K.A.
Hudson, A.
Eckert, D.J.
Editors
Advisors
Journal Title
Journal ISSN
Volume Title
Type:
Conference item
Citation
American Journal of Respiratory and Critical Care Medicine, 2025, vol.211, iss.Supplement_1, pp.A6883-1-A6883-1
Statement of Responsibility
T. J. Altree, A. Pinczel, B. Toson, K. A. Loffler, A. Hudson, D. J. Eckert
Conference Name
International Conference of the American Thoracic Society (ATS) (16 May 2025 - 21 May 2025 : San Francisco, CA)
Abstract
<jats:title>Abstract</jats:title>
<jats:p>Rationale: In people with COPD, low-dose morphine impairs ventilation during sleep, resulting in blood gas disturbances. The mechanisms causing these changes are unclear, but may relate to diminished respiratory effort. Sensory aspects of breathlessness, such as breathing effort, can be tested with the use of externally applied inspiratory resistive loads. Methods: Analysis of inspiratory resistive load magnitude perception before and after sleep from a double-blind, randomized cross-over trial of 20mg/day oral sustained-release morphine versus placebo in people with COPD and breathlessness. After three days of the assigned study intervention, six resistive loads of varying magnitude were applied three times each, three breaths at a time in random order via nasal mask before and after in-lab polysomnography (PSG). Mean Borg score of difficulty breathing and nadir mask pressure were recorded for each load. Resistive load magnitude perception was compared between conditions using linear mixed model analysis. Results: Nineteen participants with COPD completed the study protocol (mean±SD age 71±7 years). Across all resistive loads, mean peak inspiratory flow was not different between placebo vs. morphine (evening: 0.6±0.1L/s vs. 0.7±0.1L/s, p=0.46; morning: 0.6±0.1L/s vs. 0.7±0.1L/s, p=0.28). There were no differences between conditions in Borg scores versus nadir mask pressure either before or after the PSG (Figure 1). Inspiratory and expiratory time, respiratory rate and tidal volume were also not different either in the evening or in the morning between placebo and morphine conditions. Despite these neutral effects, mean and peak transcutaneous carbon dioxide (TcCO2) levels were significantly higher with morphine compared to placebo during sleep (mean and peak TcCO2 levels 3.3 [1.6 to 5.1] and 4.4 [2.2 to 6.7]mmHg higher versus placebo, respectively, both p&lt;0.001). Conclusions: Low-dose morphine does not alter key respiratory parameters or perception of externally applied inspiratory resistive loads to breathing during wakefulness. These neutral effects do not explain why low-dose morphine causes ventilatory impairment during sleep, when the respiratory system is presumably more vulnerable to the respiratory depressant effects of morphine. Figure 1. Respiratory resistive load magnitude perception results on the third night of low-dose morphine (20mg daily) or placebo administration immediately prior to overnight polysomnography (A) and the following morning (B).</jats:p>
<jats:p/>
School/Discipline
Dissertation Note
Provenance
Description
C75 COPD: STRUCTURE AND FUNCTION / Thematic Poster Session / Tuesday, May 20/09:15 AM-04:15 PM / Area C, Hall F (North Building, Exhibition Level), Moscone Center.
Abstract #A6883