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Luu BL, Lewis RHC, Gandevia SC, Boswell-Ruys CL, Butler JE. The detection and sensory perception of inspiratory resistive loads in people with chronic tetraplegia. J Appl Physiol (1985) 2022; 133:1192-1201. [PMID: 36107987 DOI: 10.1152/japplphysiol.00064.2022] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023] Open
Abstract
This study investigated sensations of breathing following tetraplegia. Fifteen people with chronic tetraplegia and fifteen healthy able-bodied controls matched for age, sex, height, and weight participated. Sensations of breathing were quantified by determining the threshold for detecting an added resistance during inspiration. In a separate task, the perceived magnitudes of six suprathreshold resistive loads were determined with a modified Borg scale. The detection threshold of 0.34 cmH2O/L/s [standard deviation (SD) 0.14] in the tetraplegia group was higher than the 0.23 cmH2O/L/s (SD 0.10) threshold for able-bodied controls (P = 0.004). Both participant groups perceived larger loads to be more effortful, with the Borg effort rating increasing linearly with the peak inspiratory pressure generated at each load. The relationship between Borg effort rating and peak inspiratory pressure was steeper in participants with tetraplegia than in able-bodied controls (P = 0.001), but there was no difference when pressure was divided by maximal inspiratory pressure (P = 0.95). Despite a higher detection threshold, the findings suggest that the perceived magnitude of a suprathreshold inspiratory load is not impaired in chronic tetraplegia and that load magnitude perception is related to the maximal, and not absolute, inspiratory muscle force.NEW & NOTEWORTHY Sensations of breathing are thought to be impaired following chronic tetraplegia. The detection threshold for an added resistive load during inspiration was higher in people with tetraplegia than in healthy able-bodied participants. However, for inspiratory loads above the detection threshold, the perceived magnitude of a resistive load as a function of the peak inspiratory pressure was greater in tetraplegia. Load magnitude perception was comparable between participant groups when peak pressure was divided by maximal inspiratory pressure.
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Affiliation(s)
- Billy L Luu
- Neuroscience Research Australia, Randwick, New South Wales, Australia
| | - R H Chaminda Lewis
- Neuroscience Research Australia, Randwick, New South Wales, Australia.,Prince of Wales Hospital, Randwick, New South Wales, Australia
| | - Simon C Gandevia
- Neuroscience Research Australia, Randwick, New South Wales, Australia.,University of New South Wales, Sydney, New South Wales, Australia.,Prince of Wales Hospital, Randwick, New South Wales, Australia
| | - Claire L Boswell-Ruys
- Neuroscience Research Australia, Randwick, New South Wales, Australia.,University of New South Wales, Sydney, New South Wales, Australia.,Prince of Wales Hospital, Randwick, New South Wales, Australia
| | - Jane E Butler
- Neuroscience Research Australia, Randwick, New South Wales, Australia.,University of New South Wales, Sydney, New South Wales, Australia
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2
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Eckert DJ, Yaggi HK. Opioid Use Disorder, Sleep Deficiency, and Ventilatory Control: Bidirectional Mechanisms and Therapeutic Targets. Am J Respir Crit Care Med 2022; 206:937-949. [PMID: 35649170 PMCID: PMC9801989 DOI: 10.1164/rccm.202108-2014ci] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2021] [Accepted: 05/31/2022] [Indexed: 01/07/2023] Open
Abstract
Opioid use continues to rise globally. So too do the associated adverse consequences. Opioid use disorder (OUD) is a chronic and relapsing brain disease characterized by loss of control over opioid use and impairments in cognitive function, mood, pain perception, and autonomic activity. Sleep deficiency, a term that encompasses insufficient or disrupted sleep due to multiple potential causes, including sleep disorders, circadian disruption, and poor sleep quality or structure due to other medical conditions and pain, is present in 75% of patients with OUD. Sleep deficiency accompanies OUD across the spectrum of this addiction. The focus of this concise clinical review is to highlight the bidirectional mechanisms between OUD and sleep deficiency and the potential to target sleep deficiency with therapeutic interventions to promote long-term, healthy recovery among patients in OUD treatment. In addition, current knowledge on the effects of opioids on sleep quality, sleep architecture, sleep-disordered breathing, sleep apnea endotypes, ventilatory control, and implications for therapy and clinical practice are highlighted. Finally, an actionable research agenda is provided to evaluate the basic mechanisms of the relationship between sleep deficiency and OUD and the potential for behavioral, pharmacologic, and positive airway pressure treatments targeting sleep deficiency to improve OUD treatment outcomes.
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Affiliation(s)
- Danny J. Eckert
- Adelaide Institute for Sleep Health, Flinders Health and Medical Research Institute, Flinders University, Bedford Park, South Australia, Australia
| | - H. Klar Yaggi
- Department of Internal Medicine, Yale University School of Medicine, New Haven, Connecticut; and
- Clinical Epidemiology Research Center, Veterans Administration Connecticut Healthcare System, West Haven, Connecticut
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Wallace ES, Carberry JC, Toson B, Eckert DJ. A Systematic Review and Meta-Analysis of Upper Airway Sensation in Obstructive Sleep Apnea – Implications for Pathogenesis, Treatment and Future Research Directions. Sleep Med Rev 2022; 62:101589. [DOI: 10.1016/j.smrv.2022.101589] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2021] [Revised: 01/04/2022] [Accepted: 01/05/2022] [Indexed: 10/19/2022]
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Zha S, Yang H, Yue F, Zhang Q, Hu K. The influence of acute morphine use on obstructive sleep apnea: A systematic review and meta-analysis. J Sleep Res 2021; 31:e13523. [PMID: 34806800 DOI: 10.1111/jsr.13523] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2021] [Revised: 10/23/2021] [Accepted: 11/08/2021] [Indexed: 12/01/2022]
Abstract
The present study was conducted to systematically evaluate the acute effect of morphine on obstructive sleep apnea (OSA). The PubMed, Embase, Cochrane Library, Clinicaltrials.gov, China National Knowledge Infrastructure (CNKI), and Wan-Fang databases were searched for randomised controlled trials studying the influence of morphine on OSA published up to May 24, 2021. The Cochrane risk of bias tool was used to assess study quality and meta-analysis was performed on the included clinical trial results to quantify the impact of morphine on various sleep and respiratory parameters. Three studies (n = 132 patients) were ultimately examined. There were no significant differences between patients with OSA taking morphine and placebo/non-opioids with respect to the sleep Apnea-Hypopnea Index (mean difference [MD] 1.78, 95% confidence interval [CI] -2.41, 5.98; p > 0.05); Oxygen Desaturation Index (MD 1.49, 95% CI -3.21, 6.19; p > 0.05); Obstructive Sleep Apnea Index (MD 0.83, 95% CI -2.08, 3.75; p > 0.05); Hypopnea Index (MD -0.01, 95% CI -2.64, 2.63; p > 0.05); lowest oxygen saturation (MD 0.68, 95% CI -4.50, 5.86; p > 0.05); or sleep oxygen saturation >90% (MD 0.10, 95% CI -1.14, 1.34; p > 0.05). In conclusion, a single dose of 30 or 40 mg morphine does not have a significant effect on sleep or respiratory outcomes compared to placebo in patients with OSA, challenging the orthodoxy that opioids worsen OSA.
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Affiliation(s)
- Shiqian Zha
- Department of Respiratory and Critical Care Medicine, Renmin Hospital of Wuhan University, Wuhan, China
| | - Haizhen Yang
- Department of Respiratory and Critical Care Medicine, Renmin Hospital of Wuhan University, Wuhan, China
| | - Fang Yue
- Department of Respiratory and Critical Care Medicine, Renmin Hospital of Wuhan University, Wuhan, China
| | - Qingfeng Zhang
- Department of Respiratory and Critical Care Medicine, Renmin Hospital of Wuhan University, Wuhan, China
| | - Ke Hu
- Department of Respiratory and Critical Care Medicine, Renmin Hospital of Wuhan University, Wuhan, China
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Rowe LM, Connor NP, Russell JA. Respiratory-swallow coordination in a rat model of chemoradiation. Head Neck 2021; 43:2954-2966. [PMID: 34160109 DOI: 10.1002/hed.26782] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2020] [Revised: 05/05/2021] [Accepted: 06/03/2021] [Indexed: 12/13/2022] Open
Abstract
BACKGROUND Chemoradiation treatment (CRT) for head and neck cancer (HNC) is associated with postswallow inhale events that elevate the risk of penetration/aspiration. The purpose of this study was to assess the validity of a rat model for investigating the effect of CRT on respiratory-swallow coordination. METHODS Videofluoroscopic swallow study was performed on 10 Sprague-Dawley rats 3 months post-CRT (3 mg/kg Cisplatin, 10 fractions of 4.5 Gy/day radiotherapy to tongue base), and 10 naïve controls. We examined the effect of CRT on swallow apnea duration, diaphragm movement, and bolus kinematics. RESULTS CRT rats had a significant increase in postswallow inhale (p = 0.008), which was associated with significantly longer swallow apnea durations, lower diaphragm displacement at swallow onset, and faster pharyngoesophageal bolus speed. CONCLUSION The rat CRT model is valid for the study of respiratory-swallow coordination due to the consistency of findings in this study with those reported in clinical CRT studies in HNC.
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Affiliation(s)
- Linda M Rowe
- Department of Communication Sciences and Disorders, University of Wisconsin-Madison, Madison, Wisconsin, USA.,Department of Surgery-Otolaryngology, University of Wisconsin-Madison, Madison, Wisconsin, USA
| | - Nadine P Connor
- Department of Communication Sciences and Disorders, University of Wisconsin-Madison, Madison, Wisconsin, USA.,Department of Surgery-Otolaryngology, University of Wisconsin-Madison, Madison, Wisconsin, USA
| | - John A Russell
- Department of Surgery-Otolaryngology, University of Wisconsin-Madison, Madison, Wisconsin, USA
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Doufas AG, Weingarten TN. Pharmacologically Induced Ventilatory Depression in the Postoperative Patient: A Sleep-Wake State-Dependent Perspective. Anesth Analg 2021; 132:1274-1286. [PMID: 33857969 DOI: 10.1213/ane.0000000000005370] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
Pharmacologically induced ventilatory depression (PIVD) is a common postoperative complication with a spectrum of severity ranging from mild hypoventilation to severe ventilatory depression, potentially leading to anoxic brain injury and death. Recent studies, using continuous monitoring technologies, have revealed alarming rates of previously undetected severe episodes of postoperative ventilatory depression, rendering the recognition of such episodes by the standard intermittent assessment practice, quite problematic. This imprecise description of the epidemiologic landscape of PIVD has thus stymied efforts to understand better its pathophysiology and quantify relevant risk factors for this postoperative complication. The residual effects of various perianesthetic agents on ventilatory control, as well as the multiple interactions of these drugs with patient-related factors and phenotypes, make postoperative recovery of ventilation after surgery and anesthesia a highly complex physiological event. The sleep-wake, state-dependent variation in the control of ventilation seems to play a central role in the mechanisms potentially enhancing the risk for PIVD. Herein, we discuss emerging evidence regarding the epidemiology, risk factors, and potential mechanisms of PIVD.
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Affiliation(s)
- Anthony G Doufas
- From the Department of Anesthesiology, Perioperative and Pain Medicine, Stanford University School of Medicine, Stanford, California
| | - Toby N Weingarten
- Department of Anesthesiology and Perioperative Medicine, College of Medicine, Mayo Clinic, Rochester, Minnesota
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Mir S, Wong J, Ryan CM, Bellingham G, Singh M, Waseem R, Eckert DJ, Chung F. Concomitant benzodiazepine and opioids decrease sleep apnoea risk in chronic pain patients. ERJ Open Res 2020; 6:00093-2020. [PMID: 32864381 PMCID: PMC7445118 DOI: 10.1183/23120541.00093-2020] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2020] [Accepted: 05/13/2020] [Indexed: 01/19/2023] Open
Abstract
Background The concurrent use of sedating centrally acting drugs and opioids by chronic pain patients occurs routinely despite concerns of negative impacts on respiration during sleep. The effects of centrally acting drugs and opioids on sleep apnoea have not been well characterised. The objective of this study was to assess the effect of concomitant centrally acting drugs and opioids on the prevalence and severity of sleep apnoea in chronic pain patients. Methods We conducted a prospective cohort study at five chronic pain clinics. Each participant underwent an in-laboratory polysomnography and daily morphine milligram equivalents were calculated. Participants were grouped into centrally acting drugs and opioid users versus sole opioid users. Results Of the 332 consented participants, 204 underwent polysomnography and 120 (58.8%) had sleep apnoea (72% obstructive, 20% central, and 8% indeterminate sleep apnoea). Overall, 35% (71 of 204) were taking opioids alone, and 65% (133 of 204) were taking centrally acting drugs and opioids. There was a 69% decrease in the odds of having sleep apnoea (apnoea–hypopnoea index ≥5 events·h−1) in participants taking benzodiazepine/opioids versus sole opioid users (OR 0.31, 95% CI:0.12–0.80, p=0.015). Additionally, concomitant benzodiazepine/opioids versus sole opioid use was associated with a decrease in respiratory arousal index scores (p=0.03). Mean overnight SpO2 was approximately 1% lower in the concomitant benzodiazepine/opioids group versus sole opioid users (93.1±2.5 versus 94.4±2.1%, p=0.01). Conclusion In chronic pain patients on opioids, administration of certain benzodiazepine sedatives induced a mild respiratory depression but paradoxically reduced sleep apnoea risk and severity by increasing the respiratory arousal threshold. There may be potential to reduce sleep apnoea risk and severity in specific chronic pain patients on opioids using certain benzodiazepine sedatives by selecting those with a low respiratory arousal threshold in whom sleep promotion may stabilise breathinghttps://bit.ly/2Zj4WX1
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Affiliation(s)
- Soodaba Mir
- Dept of Anesthesia and Pain Medicine, University Health Network, University of Toronto, Toronto, ON, Canada
| | - Jean Wong
- Dept of Anesthesia and Pain Medicine, University Health Network, University of Toronto, Toronto, ON, Canada.,Dept of Anesthesia and Pain Medicine, Women's College Hospital, University of Toronto, Toronto, ON, Canada
| | - Clodagh M Ryan
- Centre of Sleep Health and Research, Dept of Medicine, University Health Network, University of Toronto, Toronto, ON, Canada
| | - Geoff Bellingham
- Dept of Anesthesia and Perioperative Medicine, St Joseph's Health Care, Western University, London, ON, Canada
| | - Mandeep Singh
- Dept of Anesthesia and Pain Medicine, University Health Network, University of Toronto, Toronto, ON, Canada
| | - Rida Waseem
- Dept of Anesthesia and Pain Medicine, University Health Network, University of Toronto, Toronto, ON, Canada
| | - Danny J Eckert
- Adelaide Institute for Sleep Health, Flinders University, Bedford Park, SA, Australia
| | - Frances Chung
- Dept of Anesthesia and Pain Medicine, University Health Network, University of Toronto, Toronto, ON, Canada
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Boswell-Ruys CL, Lewis C, McBain RA, Gandevia SC, Butler JE. The reliability of inspiratory resistive load magnitude and detection testing. Respir Physiol Neurobiol 2020; 281:103490. [PMID: 32712538 DOI: 10.1016/j.resp.2020.103490] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2020] [Revised: 06/21/2020] [Accepted: 07/05/2020] [Indexed: 01/10/2023]
Abstract
OBJECTIVES To assess the test-retest reliability of inspiratory load detection and load magnitude perception tests in healthy volunteers. DESIGN Cohort of convenience. SETTING Respiratory physiology laboratory. PARTICIPANTS Twenty healthy adults. INTERVENTIONS On two separate occasions participants performed tests of inspiratory loading. Participants breathed through custom made resistive tubing and were asked to indicate when they detected a different resistance during inspiration. In a second test participants rated the magnitude of presented inspiratory loads using the modified Borg score. MAIN OUTCOME MEASURES Intra-class Correlation Coefficient (ICC2,1) values for repeated tests of inspiratory load detection threshold and load magnitude rating. RESULTS ICC2,1 values ranged from 0.657-0.786 for load detection testing and 0.739 to 0.969 for rating of load magnitude. CONCLUSIONS The tests are simple and reliable measures of inspiratory load detection and magnitude rating. They can be used in future research to determine the effectiveness of interventions to reduce the effort of breathing in health and disease.
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Affiliation(s)
- Claire L Boswell-Ruys
- Neuroscience Research Australia, Randwick, 2031, Australia; University of New South Wales, Sydney, 2052, Australia; Prince of Wales Hospital, Randwick, 2031, Australia.
| | - Chaminda Lewis
- Neuroscience Research Australia, Randwick, 2031, Australia; University of New South Wales, Sydney, 2052, Australia; Prince of Wales Hospital, Randwick, 2031, Australia
| | - Rachel A McBain
- Neuroscience Research Australia, Randwick, 2031, Australia; University of New South Wales, Sydney, 2052, Australia
| | - Simon C Gandevia
- Neuroscience Research Australia, Randwick, 2031, Australia; University of New South Wales, Sydney, 2052, Australia; Prince of Wales Hospital, Randwick, 2031, Australia
| | - Jane E Butler
- Neuroscience Research Australia, Randwick, 2031, Australia; University of New South Wales, Sydney, 2052, Australia
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Martins RT, Carberry JC, Wang D, Rowsell L, Grunstein RR, Eckert DJ. Morphine alters respiratory control but not other key obstructive sleep apnoea phenotypes: a randomised trial. Eur Respir J 2020; 55:13993003.01344-2019. [DOI: 10.1183/13993003.01344-2019] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2019] [Accepted: 02/25/2020] [Indexed: 11/05/2022]
Abstract
Accidental opioid-related deaths are increasing. These often occur during sleep. Opioids such as morphine may worsen obstructive sleep apnoea (OSA). Thus, people with OSA may be at greater risk of harm from morphine. Possible mechanisms include respiratory depression and reductions in drive to the pharyngeal muscles to increase upper airway collapsibility. However, the effects of morphine on the four key phenotypic causes of OSA (upper airway collapsibility (pharyngeal critical closure pressure; Pcrit), pharyngeal muscle responsiveness, respiratory arousal threshold and ventilatory control (loop gain) during sleep) are unknown.21 males with OSA (apnoea–hypopnoea index range 7–67 events·h−1) were studied on two nights (1-week washout) according to a double-blind, randomised, cross-over design (ACTRN12613000858796). Participants received 40 mg of MS-Contin on one visit and placebo on the other. Brief reductions in continuous positive airway pressure (CPAP) from the therapeutic level were delivered to induce airflow limitation during non-rapid eye movement (REM) sleep to quantify the four phenotypic traits. Carbon dioxide was delivered via nasal mask on therapeutic CPAP to quantify hypercapnic ventilatory responses during non-REM sleep.Compared to placebo, 40 mg of morphine did not change Pcrit (−0.1±2.4 versus −0.4±2.2 cmH2O, p=0.58), genioglossus muscle responsiveness (−2.2 (−0.87 to −5.4) versus −1.2 (−0.3 to −3.5) μV·cmH2O−1, p=0.22) or arousal threshold (−16.7±6.8 versus −15.4±6.0 cmH2O, p=0.41), but did reduce loop gain (−10.1±2.6 versus −4.4±2.1, p=0.04) and hypercapnic ventilatory responses (7.3±1.2 versus 6.1±1.5 L·min−1, p=0.006).Concordant with recent clinical findings, 40 mg of MS-Contin does not systematically impair airway collapsibility, pharyngeal muscle responsiveness or the arousal threshold in moderately severe OSA patients. However, consistent with blunted chemosensitivity, ventilatory control is altered.
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Ferreira DH, Ekström M, Sajkov D, Vandersman Z, Eckert DJ, Currow DC. Extended-Release Morphine for Chronic Breathlessness in Pulmonary Arterial Hypertension-A Randomized, Double-Blind, Placebo-Controlled, Crossover Study. J Pain Symptom Manage 2018; 56:483-492. [PMID: 30031217 DOI: 10.1016/j.jpainsymman.2018.07.010] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/31/2018] [Revised: 07/09/2018] [Accepted: 07/11/2018] [Indexed: 12/28/2022]
Abstract
CONTEXT Pulmonary arterial hypertension (PAH) affects people of all ages and is associated with poor prognosis. Chronic breathlessness affects almost all people with PAH. OBJECTIVES This randomized, placebo-controlled, double-blind, crossover study aimed to evaluate the effects of regular, low-dose, extended-release (ER) morphine for PAH-associated chronic breathlessness. METHODS Participants with PAH-associated chronic breathlessness were randomized to 1) seven days of ER morphine 20 mg, 2) seven-day washout, and 3) seven days of identically looking placebo, or vice versa. Primary end points were breathlessness "right now"-morning and evening-measured with a Visual Analogue Scale. Secondary end points included additional breathlessness measures, quality of life, function, harms, and blinded treatment preference (ACTRN12609000209291). RESULTS Within a period of seven years, 50 patients were assessed in detail and 23 (46%) were randomized (despite broad eligibility criteria). Four participants withdrew while taking morphine. Nineteen participants completed the study. Breathlessness "right now" was higher on morphine compared with placebo both for morning [mean (M) ± SD 31.7 ± 25 mm vs. 26.9 ± 22 mm; effect size (80% CI) = -0.22 (-0.6 to 0.2)] and evening [(M ± SD 33.5 ± 28 mm vs. 25.6 ± 21 mm; effect size (80% CI) = -0.33 (-0.8 to 0.1)]. All secondary measures of breathlessness were higher with morphine as were nausea and constipation. CONCLUSION This study does not support a Phase III study of ER morphine for people with PAH-associated chronic breathlessness. Recruiting to the target sample size was difficult, the direction of effect in every measure of breathlessness favored placebo and morphine generated more harms.
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Affiliation(s)
- Diana H Ferreira
- Discipline, Palliative and Supportive Services, Flinders University, Adelaide, South Australia, Australia.
| | - Magnus Ekström
- Division of Respiratory Medicine & Allergology, Department of Clinical Sciences, Lund University, Lund, Sweden
| | - Dimitar Sajkov
- Australian Respiratory and Sleep Medicine Institute and Department of Respiratory and Sleep Medicine, Flinders Medical Centre, Adelaide, Australia
| | - Zac Vandersman
- IMPACCT, Faculty of Health, University of Technology Sydney, Sydney, New South Wales, Australia
| | - Danny J Eckert
- Neuroscience Research Australia (NeuRA) and School of Medical Sciences, University of New South Wales, Sydney, Australia
| | - David C Currow
- Discipline, Palliative and Supportive Services, Flinders University, Adelaide, South Australia, Australia; IMPACCT, Faculty of Health, University of Technology Sydney, Sydney, New South Wales, Australia; Wolfson Centre for Palliative Care Research, University of Hull, Hull, England
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