Inhaled fentanyl citrate improves exercise endurance during high-intensity constant work rate cycle exercise in chronic obstructive pulmonary disease

Dyspnoea in acutely ill mechanically ventilated adult patients: an ERS/ESICM statement

This statement outlines a review of the literature and current practice concerning the prevalence, clinical significance, diagnosis and management of dyspnoea in critically ill, mechanically ventilated adult patients. It covers the definition, pathophysiology, epidemiology, short- and middle-term impact, detection and quantification, and prevention and treatment of dyspnoea. It represents a collaboration of the European Respiratory Society and the European Society of Intensive Care Medicine. Dyspnoea ranks among the most distressing experiences that human beings can endure. Approximately 40% of patients undergoing invasive mechanical ventilation in the intensive care unit (ICU) report dyspnoea, with an average intensity of 45 mm on a visual analogue scale from 0 to 100 mm. Although it shares many similarities with pain, dyspnoea can be far worse than pain in that it summons a primal fear response. As such, it merits universal and specific consideration. Dyspnoea must be identified, prevented and relieved in every patient. In the ICU, mechanically ventilated patients are at high risk of experiencing breathing difficulties because of their physiological status and, in some instances, because of mechanical ventilation itself. At the same time, mechanically ventilated patients have barriers to signalling their distress. Addressing this major clinical challenge mandates teaching and training, and involves ICU caregivers and patients. This is even more important because, as opposed to pain which has become a universal healthcare concern, very little attention has been paid to the identification and management of respiratory suffering in mechanically ventilated ICU patients.

Dyspnoea in acutely ill mechanically ventilated adult patients: an ERS/ESICM statement

This statement outlines a review of the literature and current practice concerning the prevalence, clinical significance, diagnosis and management of dyspnoea in critically ill, mechanically ventilated adult patients. It covers the definition, pathophysiology, epidemiology, short- and middle-term impact, detection and quantification, and prevention and treatment of dyspnoea. It represents a collaboration of the European Respiratory Society (ERS) and the European Society of Intensive Care Medicine (ESICM). Dyspnoea ranks among the most distressing experiences that human beings can endure. Approximately 40% of patients undergoing invasive mechanical ventilation in the intensive care unit (ICU) report dyspnoea, with an average intensity of 45 mm on a visual analogue scale from 0 to 100 mm. Although it shares many similarities with pain, dyspnoea can be far worse than pain in that it summons a primal fear response. As such, it merits universal and specific consideration. Dyspnoea must be identified, prevented and relieved in every patient. In the ICU, mechanically ventilated patients are at high risk of experiencing breathing difficulties because of their physiological status and, in some instances, because of mechanical ventilation itself. At the same time, mechanically ventilated patients have barriers to signalling their distress. Addressing this major clinical challenge mandates teaching and training, and involves ICU caregivers and patients. This is even more important because, as opposed to pain which has become a universal healthcare concern, very little attention has been paid to the identification and management of respiratory suffering in mechanically ventilated ICU patients.

Effectiveness and safety of opioids on breathlessness and exercise endurance in patients with chronic obstructive pulmonary disease: A systematic review and meta-analysis of randomised controlled trials

BACKGROUND

Opioids are recommended to treat advanced refractory dyspnoea despite optimal therapy by the American Thoracic Society clinical practice guidelines, while newly published randomised controlled trials of opioids in chronic obstructive pulmonary disease yield conflicting results.

AIM

This study aimed to evaluate the effectiveness and safety of opioids for patients with chronic obstructive pulmonary disease.

DESIGN

Systematic review and meta-analysis (PROSPERO CRD42021272556).

DATA SOURCES

Databases of PubMed, EMBASE and CENTRAL were searched from inception to 2022 for eligible randomised controlled trials.

RESULTS

Twenty-four studies including 975 patients, were included. In cross-over studies, opioids improved breathlessness (standardised mean difference, -0.43; 95% CI, -0.55 to -0.30; I2 = 18%) and exercise endurance (standardised mean difference, 0.22; 95% CI, 0.02-0.41; I2 = 70%). However, opioids failed to improve dyspnoea (standardised mean difference, -0.02; 95% CI, -0.22 to 0.19; I2 = 39%) and exercise endurance (standardised mean difference, 0.00; 95% CI, -0.27 to 0.27; I2 = 0%) in parallel control studies that administered sustained-release opioids for more than 1 week. The opioids used in most crossover studies were short-acting and rarely associated with serious adverse effects. Only minor side effects such as dizziness, nausea, constipation and vomiting were identified for short-acting opioids.

CONCLUSIONS

Sustained-release opioids did not improve dyspnoea and exercise endurance. Short-acting opioids appeared to be safe, have potential to lessen dyspnoea and improve exercise endurance, supporting benefit in managing episodes of breathlessness and providing prophylactic treatment for exertional dyspnoea.

Fixed-intensity exercise tests to measure exertional dyspnoea in chronic heart and lung populations: a systematic review

INTRODUCTION

Exertional dyspnoea is the primary diagnostic symptom for chronic cardiopulmonary disease populations. Whilst a number of exercise tests are used, there remains no gold standard clinical measure of exertional dyspnoea. The aim of this review was to comprehensively describe and evaluate all types of fixed-intensity exercise tests used to assess exertional dyspnoea in chronic cardiopulmonary populations and, where possible, report the reliability and responsiveness of the tests.

METHODS

A systematic search of five electronic databases identified papers that examined 1) fixed-intensity exercise tests and measured exertional dyspnoea, 2) chronic cardiopulmonary populations, 3) exertional dyspnoea reported at isotime or upon completion of fixed-duration exercise tests, and 4) published in English.

RESULTS

Searches identified 8785 papers. 123 papers were included, covering exercise tests using a variety of fixed-intensity protocols. Three modes were identified, as follows: 1) cycling (n=87), 2) walking (n=31) and 3) other (step test (n=8) and arm exercise (n=2)). Most studies (98%) were performed on chronic respiratory disease patients. Nearly all studies (88%) used an incremental exercise test. 34% of studies used a fixed duration for the exercise test, with the remaining 66% using an exhaustion protocol recording exertional dyspnoea at isotime. Exertional dyspnoea was measured using the Borg scale (89%). 7% of studies reported reliability. Most studies (72%) examined the change in exertional dyspnoea in response to different interventions.

CONCLUSION

Considerable methodological variety of fixed-intensity exercise tests exists to assess exertional dyspnoea and most test protocols require incremental exercise tests. There does not appear to be a simple, universal test for measuring exertional dyspnoea in the clinical setting.

Impact of trigeminal nerve and/or olfactory nerve stimulation on activity of human brain regions involved in the perception of breathlessness

Breathlessness is a centrally processed symptom, as evidenced by activation of distinct brain regions such as the insular cortex and amygdala, during the anticipation and/or perception of breathlessness. Inhaled L-menthol or blowing cool air to the face/nose, both selective trigeminal nerve (TGN) stimulants, relieve breathlessness without concurrent improvements in physiological outcomes (e.g., breathing pattern), suggesting a possible but hitherto unexplored central mechanism of action. Four databases were searched to identify published reports supporting a link between TGN stimulation and activation of brain regions involved in the anticipation and/or perception of breathlessness. The collective results of the 29 studies demonstrated that TGN stimulation activated 12 brain regions widely implicated in the anticipation and/or perception of breathlessness, including the insular cortex and amygdala. Inhaled L-menthol or cool air to the face activated 75% and 33% of these 12 brain regions, respectively. Our findings support the hypothesis that TGN stimulation contributes to breathlessness relief by altering the activity of brain regions involved in its central neural processing.

Low dose of morphine to relieve dyspnea in acute respiratory failure (OpiDys): protocol for a double-blind randomized controlled study

Background

Dyspnea is common and severe in intensive care unit (ICU) patients managed for acute respiratory failure. Dyspnea appears to be associated with impaired prognosis and neuropsychological sequels. Pain and dyspnea share many similarities and previous studies have shown the benefit of morphine on dyspnea in patients with end-stage onco-hematological disease and severe heart or respiratory disease. In these populations, morphine administration was safe. Here, we hypothesize that low-dose opioids may help to reduce dyspnea in patients admitted to the ICU for acute respiratory failure. The primary objective of the trial is to determine whether the administration of low-dose titrated opioids, compared to placebo, in patients admitted to the ICU for acute respiratory failure with severe dyspnea decreases the mean 24-h intensity of dyspnea score.

Methods

In this single-center double-blind randomized controlled trial with 2 parallel arms, we plan to include 22 patients (aged 18–75 years) on spontaneous ventilation with either non-invasive ventilation, high flow oxygen therapy or standard oxygen therapy admitted to the ICU for acute respiratory failure with severe dyspnea. They will be assigned after randomization with a 1:1 allocation ratio to receive in experimental arm administration of low-dose titrated morphine hydrochloride for 24 h consisting in an intravenous titration relayed subcutaneously according to a predefined protocol, or a placebo (0.9% NaCl) administered according to the same protocol in the control arm. The primary endpoint is the mean 24-h dyspnea score assessed by a visual analog scale of dyspnea.

Discussion

To our knowledge, this study is the first to evaluate the benefit of opioids on dyspnea in ICU patients admitted for acute respiratory failure.

Trial registration

ClinicalTrials.govNCT04358133. Registered on 24 April 2020.

Spanish COPD Guideline (GesEPOC) Update: Comorbidities, Self-Management and Palliative Care

The current health care models described in GesEPOC indicate the best way to make a correct diagnosis, the categorization of patients, the appropriate selection of the therapeutic strategy and the management and prevention of exacerbations. In addition, COPD involves several aspects that are crucial in an integrated approach to the health care of these patients. The evaluation of comorbidities in COPD patients represents a healthcare challenge. As part of a comprehensive assessment, the presence of comorbidities related to the clinical presentation, to some diagnostic technique or to some COPD-related treatments should be studied. Likewise, interventions on healthy lifestyle habits, adherence to complex treatments, developing skills to recognize the signs and symptoms of exacerbation, knowing what to do to prevent them and treat them within the framework of a self-management plan are also necessary. Finally, palliative care is one of the pillars in the comprehensive treatment of the COPD patient, seeking to prevent or treat the symptoms of a disease, the side effects of treatment, and the physical, psychological and social problems of patients and their caregivers. Therefore, the main objective of this palliative care is not to prolong life expectancy, but to improve its quality. This chapter of GesEPOC 2021 presents an update on the most important comorbidities, self-management strategies, and palliative care in COPD, and includes a recommendation on the use of opioids for the treatment of refractory dyspnea in COPD.

Dyspnea

The clinical term dyspnea (a.k.a. breathlessness or shortness of breath) encompasses at least three qualitatively distinct sensations that warn of threats to breathing: air hunger, effort to breathe, and chest tightness. Air hunger is a primal homeostatic warning signal of insufficient alveolar ventilation that can produce fear and anxiety and severely impacts the lives of patients with cardiopulmonary, neuromuscular, psychological, and end-stage disease. The sense of effort to breathe informs of increased respiratory muscle activity and warns of potential impediments to breathing. Most frequently associated with bronchoconstriction, chest tightness may warn of airway inflammation and constriction through activation of airway sensory nerves. This chapter reviews human and functional brain imaging studies with comparison to pertinent neurorespiratory studies in animals to propose the interoceptive networks underlying each sensation. The neural origins of their distinct sensory and affective dimensions are discussed, and areas for future research are proposed. Despite dyspnea's clinical prevalence and impact, management of dyspnea languishes decades behind the treatment of pain. The neurophysiological bases of current therapeutic approaches are reviewed; however, a better understanding of the neural mechanisms of dyspnea may lead to development of novel therapies and improved patient care.

A critical review of the respiratory benefits and harms of orally administered opioids for dyspnea management in COPD

INTRODUCTION

Dyspnea occurring in chronic obstructive pulmonary disease (COPD) that is refractory to traditional management strategies is a common and challenging problem. Considerable attention has been paid to the off-label use of orally administered opioids as a pharmacotherapy option for refractory dyspnea in COPD. Multiple professional respiratory society guidelines express support for the application of oral opioids for this purpose.

AREAS COVERED

This manuscript will critically review randomized controlled trials undertaken to date that evaluate the efficacy of oral opioids for dyspnea in COPD, as well as phase IV observational studies that examine for potential opioid-related respiratory harms in the COPD population (literature was searched on PubMed up to June 2021). COPD guideline recommendations relating to opioids for dyspnea will subsequently be critiqued.

EXPERT OPINION

Opioid efficacy trials demonstrate at best a small improvement in dyspnea in limited numbers of individuals with COPD, whereas safety trials consistently show an increased risk of respiratory-related exacerbation, hospitalization and death in association with opioid use. In contrast to what is expressed in guidelines, the current body of evidence does not the support the wide application of opioids to manage refractory dyspnea among individuals with COPD, but instead, a highly selective and careful approach.

Opioids in patients with COPD and refractory dyspnea: literature review and design of a multicenter double blind study of low dosed morphine and fentanyl (MoreFoRCOPD)

Background

Refractory dyspnea or breathlessness is a common symptom in patients with advanced chronic obstructive pulmonary disease (COPD), with a high negative impact on quality of life (QoL). Low dosed opioids have been investigated for refractory dyspnea in COPD and other life-limiting conditions, and some positive effects were demonstrated. However, upon first assessment of the literature, the quality of evidence in COPD seemed low or inconclusive, and focused mainly on morphine which may have more side effects than other opioids such as fentanyl. For the current publication we performed a systematic literature search. We searched for placebo-controlled randomized clinical trials investigating opioids for refractory dyspnea caused by COPD. We included trials reporting on dyspnea, health status and/or QoL. Three of fifteen trials demonstrated a significant positive effect of opioids on dyspnea. Only one of four trials reporting on QoL or health status, demonstrated a significant positive effect. Two-thirds of included trials investigated morphine. We found no placebo-controlled RCT on transdermal fentanyl. Subsequently, we hypothesized that both fentanyl and morphine provide a greater reduction of dyspnea than placebo, and that fentanyl has less side effects than morphine.

Methods

We describe the design of a robust, multi-center, double blind, double-dummy, cross-over, randomized, placebo-controlled clinical trial with three study arms investigating transdermal fentanyl 12 mcg/h and morphine sustained-release 10 mg b.i.d. The primary endpoint is change in daily mean dyspnea sensation measured on a numeric rating scale. Secondary endpoints are change in daily worst dyspnea, QoL, anxiety, sleep quality, hypercapnia, side effects, patient preference, and continued opioid use. Sixty patients with severe stable COPD and refractory dyspnea (FEV₁ < 50%, mMRC ≥ 3, on optimal standard therapy) will be included.

Discussion

Evidence for opioids for refractory dyspnea in COPD is not as robust as usually appreciated. We designed a study comparing both the more commonly used opioid morphine, and transdermal fentanyl to placebo. The cross-over design will help to get a better impression of patient preferences. We believe our study design to investigate both sustained-release morphine and transdermal fentanyl for refractory dyspnea will provide valuable information for better treatment of refractory dyspnea in COPD.

Trial registration NCT03834363 (ClinicalTrials.gov), registred at 7 Feb 2019, https://clinicaltrials.gov/ct2/show/NCT03834363.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12890-021-01647-8.

Power Reserve at Intolerance in Ramp-Incremental Exercise Is Dependent on Incrementation Rate

INTRODUCTION

The mechanism(s) of exercise intolerance at V˙O2max remain poorly understood. In health, standard ramp-incremental (RI) exercise is limited by fatigue-induced reductions in maximum voluntary cycling power. Whether neuromuscular fatigue also limits exercise when the RI rate is slow and RI peak power at intolerance is lower than standard RI exercise, is unknown.

METHODS

In twelve healthy participants, maximal voluntary cycling power was measured during a short (~6 s) isokinetic effort at 80 rpm (Piso) at baseline and, using an instantaneous switch from cadence-independent to isokinetic cycling, immediately at the limit of RI exercise with RI rates of 50, 25, and 10 W·min-1 (RI-50, RI-25, and RI-10). Breath-by-breath pulmonary gas exchange was measured throughout.

RESULTS

Baseline Piso was not different among RI rates (analysis of variance; P > 0.05). Tolerable duration increased with decreasing RI rate (RI-50, 411 ± 58 s vs RI-25, 732 ± 93 s vs RI-10, 1531 ± 288 s; P < 0.05). At intolerance, V˙O2peak was not different among RI rates (analysis of variance; P > 0.05), but RI peak power decreased with RI rate (RI-50, 361 ± 48 W vs RI-25, 323 ± 39 W vs RI-10, 275 ± 38 W; P < 0.05). Piso at intolerance was 346 ± 43 W, 353 ± 45 W, and 392 ± 69 W for RI-50, RI-25, and RI-10, respectively (P < 0.05 for RI-10 vs RI-50 and RI-25). At intolerance, in RI-50 and RI-25, Piso was not different from RI peak power (P > 0.05), thus there was no "power reserve." In RI-10, Piso was greater than RI peak power at intolerance (P < 0.001), that is, there was a "power reserve."

CONCLUSIONS

In RI-50 and RI-25, the absence of a power reserve suggests the neuromuscular fatigue-induced reduction in Piso coincided with V˙O2max and limited the exercise. In RI-10, the power reserve suggests neuromuscular fatigue was insufficient to limit the exercise, and additional mechanisms contributed to intolerance at V˙O2max.

Intranasal Fentanyl Versus Placebo for Treatment of Episodic Breathlessness in Hospice Patients With Advanced Nonmalignant Diseases

CONTEXT

Episodic breathlessness is a distressing and difficult to treat symptom because of its short duration. Fast actioned intranasal fentanyl (INF) is potentially more suitable than oral opioids.

OBJECTIVES

To examine the feasibility, preliminary efficacy, and safety of INF for the treatment of episodic breathlessness from advanced nonmalignant conditions in hospice patients.

METHODS

Phase IIB, double-blind, randomized controlled, multisite, INF citrate solution vs. placebo crossover feasibility study. Opioid-tolerant patients were to treat six episodes of breathlessness using INF spray. The primary outcome was change in the Visual Analogue Scale for dyspnea (VAS-D) score from baseline to 15 minutes after study drug's administration (VAS-D₁₅). Other outcomes were to collect demographic data and determine the use of rescue medications, safety, and feasibility of the study design.

RESULTS

Twenty-one of 49 eligible patients were enrolled, and 19 (90%) patients completed the study. The mean difference in VAS-D₁₅ between fentanyl and placebo was -3.37 mm (95% CI = -10.35 to 3.61 mm; P = 0.337). There was no statistically significant or clinically meaningful difference between INF and placebo in relieving the sensation of discomfort in episodic breathlessness. No significant drug-related adverse event or detrimental effect on vital signs was observed.

CONCLUSION

We found no difference between INF and placebo in relieving episodic breathlessness in nonmalignant conditions. INF was well tolerated, and the study design proved to be feasible in hospice patients with advanced diseases. Future study using higher concentration of fentanyl solution may be warranted.

Multidimensional breathlessness response to exercise: Impact of COPD and healthy ageing

This study compared the multidimensional breathlessness response to incremental cardiopulmonary cycle exercise testing (CPET) in people with chronic obstructive pulmonary disease (COPD; n = 14, aged 69 ± 9 years, forced expiratory volume in 1-sec = 54 ± 16 % predicted) and healthy older (OA) (n = 35, aged 68 ± 5 years) and younger (YA) (n = 19, aged 28 ± 8 years) adults. Participants performed CPET and successively rated overall breathlessness intensity, unsatisfied inspiration, breathing too shallow, work/effort of breathing, and breathlessness-related unpleasantness, fear, and anxiety using the 0-10 Borg scale. At any given percent predicted peak minute ventilation, people with COPD rated all breathlessness sensations higher than OA and YAs, who were similar. Most between group differences disappeared when examined in relation to inspiratory reserve volume, except people with COPD reported higher levels of unsatisfied inspiration and breathing too shallow (vs YA), and breathlessness-related fear and anxiety (vs OA and YAs). Multidimensional ratings of breathlessness sensations during CPET provides further insight into differences in exertional symptom perceptions among people with COPD and without COPD.

Efficacy and Safety of Opioids in Treating Cancer-Related Dyspnea: A Systematic Review and Meta-Analysis Based on Randomized Controlled Trials

BACKGROUND

Dyspnea is one of the most distressing symptoms encountered by advanced cancer patients. In this study, we aimed to evaluate the role of opioids in the management of cancer-related dyspnea.

METHODS

A systematic review and meta-analysis based on Randomized Controlled Trials was conducted in the databases PUBMED, EMBASE, and Cochrane Central Register of Controlled Trials testing the effect of opioids in relieving cancer-related dyspnea. Subgroup and sensitivity analyses were performed to evaluate various types of opioids in dyspnea management and stabilization of the study respectively.

RESULTS

Eleven RCTs fulfilled the eligibility criteria and had a total of 290 participants. Nine of these studies were included in meta-analyses. Compared with control, opioid therapy showed a small positive effect in dyspnea, SMD-0.82 (95%CI = -1.54 to -0.10) and Borg score, WMD-0.95 (95%CI = -1.83 to -0.06); Opioid therapy did not increase the risk of somnolence, OR0.93 (95%CI = 0.34 to 2.58), whereas a negative effect on respiratory rate was observed,WMD-1.89 (95%CI = -3.36 to -0.43); Also, there was no evidence to suggest improved performance of the 6MWT test, WMD6.49 (95%CI = -34.23 to 47.21), or the level of peripheral oxygen saturation, WMD0.33 (95%CI = -0.59 to 1.24) after opioid therapy. Subgroup analysis yielded a small positive effect for morphine on dyspnea, SMD-0.78 (95%CI = -1.45 to -0.10), whereas fentanyl showed no improvement in dyspnea, SMD-0.44 (95%CI = -0.89 to 0.02). Sensitivity analysis showed no changes in the direction of effect when any one study was excluded from the meta-analyses.

CONCLUSIONS

Our systematic review and meta-analysis indicated low quality evidence for a small positive effect of opioids in cancer-related dyspnea. Evidence for safety is insufficient as comprehensive adverse events were not adequately reported in studies.

High-Flow Nasal Cannula Therapy for Exertional Dyspnea in Patients with Cancer: A Pilot Randomized Clinical Trial

BACKGROUND

Exertional dyspnea is common in patients with cancer and limits their function. The impact of high-flow nasal cannula on exertional dyspnea in nonhypoxemic patients is unclear. In this double-blind, parallel-group, randomized trial, we assessed the effect of flow rate (high vs. low) and gas (oxygen vs. air) on exertional dyspnea in nonhypoxemic patients with cancer.

PATIENTS AND METHODS

Patients with cancer with oxygen saturation >90% at rest and exertion completed incremental and constant work (80% maximal) cycle ergometry while breathing low-flow air at 2 L/minute. They were then randomized to receive high-flow oxygen, high-flow air, low-flow oxygen, or low-flow air while performing symptom-limited endurance cycle ergometry at 80% maximal. The primary outcome was modified 0-10 Borg dyspnea intensity scale at isotime. Secondary outcomes included dyspnea unpleasantness, exercise time, and adverse events.

RESULTS

Seventy-four patients were enrolled, and 44 completed the study (mean age 63; 41% female). Compared with low-flow air at baseline, dyspnea intensity was significantly lower at isotime with high-flow oxygen (mean change, -1.1; 95% confidence interval [CI], -2.1, -0.12) and low-flow oxygen (-1.83; 95% CI, -2.7, -0.9), but not high-flow air (-0.2; 95% CI, -0.97, 0.6) or low-flow air (-0.5; 95% CI, -1.3, 0.4). Compared with low-flow air, high-flow oxygen also resulted in significantly longer exercise time (difference + 2.5 minutes, p = .009), but not low-flow oxygen (+0.39 minutes, p = .65) or high-flow air (+0.63 minutes, p = .48). The interventions were well tolerated without significant adverse effects.

CONCLUSION

Our preliminary findings support that high-flow oxygen improved both exertional dyspnea and exercise duration in nonhypoxemic patients with cancer. (ClinicalTrials.gov ID: NCT02357134).

IMPLICATIONS FOR PRACTICE

In this four-arm, double-blind, randomized clinical trial examining the role of high-flow nasal cannula on exertional dyspnea in patients with cancer without hypoxemia, high-flow oxygen, but not high-flow air, resulted in significantly lower dyspnea scores and longer exercise time. High-flow oxygen delivered by high-flow nasal cannula devices may improve clinically relevant outcomes even in patients without hypoxemia.

Morphine for the symptomatic reduction of chronic breathlessness: the case for controlled release

PURPOSE OF REVIEW

Clinicians who seek to reduce the symptomatic burden of chronic breathlessness by initiating regular low-dose morphine has the choice of immediate or sustained-release formulations - which will be better for this often frail population, and which has the more robust evidence to inform its prescription? Both formulations can be used.

RECENT FINDINGS

For chronic breathlessness, three factors consistently favour the use of regular, low-dose, sustained-release morphine over immediate-release formulations: SUMMARY: As the evidence base expands for the symptomatic reduction of chronic breathlessness, pharmacological interventions will play a part. Using the best available evidence underpins patient-centred approaches that seek to predictably maximize the net effect.As such, the weight of evidence in patient-centred clinical care favours the use of regular, low-dose sustained-release morphine for the symptomatic reduction of chronic breathlessness.

Pharmacologic Management of Chronic Obstructive Pulmonary Disease. An Official American Thoracic Society Clinical Practice Guideline

Background: This document provides clinical recommendations for the pharmacologic treatment of chronic obstructive pulmonary disease (COPD). It represents a collaborative effort on the part of a panel of expert COPD clinicians and researchers along with a team of methodologists under the guidance of the American Thoracic Society.

Methods: Comprehensive evidence syntheses were performed on all relevant studies that addressed the clinical questions and critical patient-centered outcomes agreed upon by the panel of experts. The evidence was appraised, rated, and graded, and recommendations were formulated using the Grading of Recommendations, Assessment, Development, and Evaluation approach.

Results: After weighing the quality of evidence and balancing the desirable and undesirable effects, the guideline panel made the following recommendations: 1) a strong recommendation for the use of long-acting β₂-agonist (LABA)/long-acting muscarinic antagonist (LAMA) combination therapy over LABA or LAMA monotherapy in patients with COPD and dyspnea or exercise intolerance; 2) a conditional recommendation for the use of triple therapy with inhaled corticosteroids (ICS)/LABA/LAMA over dual therapy with LABA/LAMA in patients with COPD and dyspnea or exercise intolerance who have experienced one or more exacerbations in the past year; 3) a conditional recommendation for ICS withdrawal for patients with COPD receiving triple therapy (ICS/LABA/LAMA) if the patient has had no exacerbations in the past year; 4) no recommendation for or against ICS as an additive therapy to long-acting bronchodilators in patients with COPD and blood eosinophilia, except for those patients with a history of one or more exacerbations in the past year requiring antibiotics or oral steroids or hospitalization, for whom ICS is conditionally recommended as an additive therapy; 5) a conditional recommendation against the use of maintenance oral corticosteroids in patients with COPD and a history of severe and frequent exacerbations; and 6) a conditional recommendation for opioid-based therapy in patients with COPD who experience advanced refractory dyspnea despite otherwise optimal therapy.

Conclusions: The task force made recommendations regarding the pharmacologic treatment of COPD based on currently available evidence. Additional research in populations that are underrepresented in clinical trials is needed, including studies in patients with COPD 80 years of age and older, those with multiple chronic health conditions, and those with a codiagnosis of COPD and asthma.

Inspiratory neural drive and dyspnea in interstitial lung disease: Effect of inhaled fentanyl

BACKGROUND

Exertional dyspnea in interstitial lung disease (ILD) remains difficult to manage despite advances in disease-targeted therapies. Pulmonary opioid receptors present a potential therapeutic target for nebulized fentanyl to provide dyspnea relief.

METHODS

ILD patients were characterized with reference to healthy volunteers. A randomized, double-blind, placebo-controlled crossover comparison of 100 mcg nebulized fentanyl vs placebo on dyspnea intensity and inspiratory neural drive (IND) during constant work rate (CWR) cycle exercise was performed in 21 ILD patients.

RESULTS

Dyspnea intensity in ILD increased in association with an increase in IND (diaphragm activation) from a high resting value of 16.66 ± 6.52 %-60.04 ± 12.52 % of maximum (r = 0.798, p < 0.001). At isotime during CWR exercise, Borg dyspnea intensity ratings with fentanyl vs placebo were 4.1 ± 1.2 vs 3.8 ± 1.2, respectively (p = 0.174), and IND responses were also similar.

CONCLUSION

IND rose sharply during constant work rate exercise in association with dyspnea intensity in mild to moderate ILD but was not different after nebulized fentanyl compared with placebo.

Palliation of chronic breathlessness with morphine in patients with fibrotic interstitial lung disease - a randomised placebo-controlled trial

Background

Patients suffering from fibrotic interstitial lung diseases (fILD) have a poor prognosis and a high symptom burden. Palliative treatment includes relief of symptoms such as breathlessness. There is no evidence-based treatment for chronic breathlessness but opioids are often used despite concerns due to the hypothetical risk of respiratory depression. This study investigated the effect of oral morphine drops in patients with fILD on chronic breathlessness and safety.

Methods

In a double-blinded placebo-controlled study, 36 patients with fILD were randomised to either four daily doses of 5 mg of oral morphine drops or placebo for 1 week. Endpoints and safety parameters were obtained at baseline, at follow-up after 1 h and 1 week.

Results

The primary endpoint, the visual analogue score (VAS) of dyspnea was reduced by 1.1 ± 0.33 cm in the morphine group at follow-up compared to baseline (P < 0.01), whereas the reduction was 0.35 ± 0.47 cm in the placebo group. However, the difference between the two groups was not statistically significant (p = 0.2). Oral morphine drops did not affect respiratory frequency, pulse rate, blood pressure, peripheral saturation or the 6-min walk test. More patients treated with morphine reported constipation, nausea and confusion.

Conclusion

Oral administration of morphine drops, 20 mg a day, in patients with fILD did not significantly reduce dyspnea VAS score during 1 week compared to placebo. Oral morphine did not induce respiratory depression, but was related to an increased risk of constipation, nausea and confusion.

Trial registration

The trial is registered in clinicaltrials.gov (Identifier: NCT02622022). Registered 4 December 2015.

Opioids for breathlessness: a narrative review

Chronic breathlessness is a disabling and distressing condition for which there is a growing evidence base for a range of interventions. Non-pharmacological interventions are the mainstay of management and should be optimised prior to use of opioid medication. Opioids are being implemented variably in practice for chronic breathlessness. This narrative review summarises the evidence defining current opioids for breathlessness best practice and identifies remaining research gaps. There is level 1a evidence to support the use of opioids for breathlessness. The best evidence is for 10–30 mg daily de novo low-dose oral sustained-release morphine in opioid-naïve patients. This should be considered the current standard of care following independent, regulatory scrutiny by one of the world’s therapeutics regulatory bodies. Optimal benefits are seen in steady state; however, there are few published data about longer term benefits or harms. Morphine-related adverse events are common but mostly mild and self-limiting on withdrawal of drug. Early and meticulous management of constipation, nausea and vomiting is needed particularly in the first week of administration. Serious adverse events are no more common than placebo in clinical studies. Observational studies in severe chronic lung disease do not show excess mortality or hospital admission in those taking opioids. We have no long-term data on immune or endocrine function. There are promising data regarding prophylaxis for exertion-related breathlessness, but given the risks associated with transmucosal fentanyl, caution is needed with regard to clinical use pending longer term, robust safety data.

Nebulized Fentanyl for Dyspnea: A Retrospective Chart Review

Nebulized fentanyl is well established for analgesia but its use for dyspnea requires further investigation. The aim of our study was to determine the effectiveness of nebulized fentanyl in treating patients with dyspnea and to determine if there were harmful side effects described by patients or their providers. We used a convenience sample of patients from July 1 2014 to July 1 2018 and performed a retrospective chart review. We found that 360 doses of nebulized fentanyl were given to 73 patients during that time period. Of the 73 patients evaluated, 32 patients (43.8%) were female and forty-one were male (56.1%). The median age was 67 and the median length of stay was 9 days. There were no documented findings of bronchospasm, hypotension, or allergic reaction in any of the medical records reviewed. Patients treated with nebulized fentanyl for dyspnea showed a mean decreased respiratory rate of 4.3 breaths/min and a mean increased oxygen saturation of 2.3%. Also, 71% of patients with documented responses experienced an improvement in their dyspnea. Our preliminary data suggest that nebulized fentanyl has limited side effects and may have a role in the treatment of dyspnea. Further research is necessary to determine its efficacy.

Dyspnea in COPD: New Mechanistic Insights and Management Implications

Dyspnea is the most common symptom experienced by patients with chronic obstructive pulmonary disease (COPD). To avoid exertional dyspnea, many patients adopt a sedentary lifestyle which predictably leads to extensive skeletal muscle deconditioning, social isolation, and its negative psychological sequalae. This “dyspnea spiral” is well documented and it is no surprise that alleviation of this distressing symptom has become a key objective highlighted across COPD guidelines. In reality, this important goal is often difficult to achieve, and successful symptom management awaits a clearer understanding of the underlying mechanisms of dyspnea and how these can be therapeutically manipulated for the patients’ benefit. Current theoretical constructs of the origins of activity-related dyspnea generally endorse the classical demand–capacity imbalance theory. Thus, it is believed that disruption of the normally harmonious relationship between inspiratory neural drive (IND) to breathe and the simultaneous dynamic response of the respiratory system fundamentally shapes the expression of respiratory discomfort in COPD. Sadly, the symptom of dyspnea cannot be eliminated in patients with advanced COPD with relatively fixed pathophysiological impairment. However, there is evidence that effective symptom palliation is possible for many. Interventions that reduce IND, without compromising alveolar ventilation (V_A), or that improve respiratory mechanics and muscle function, or that address the affective dimension, achieve measurable benefits. A common final pathway of dyspnea relief and improved exercise tolerance across the range of therapeutic interventions (bronchodilators, exercise training, ambulatory oxygen, inspiratory muscle training, and opiate medications) is reduced neuromechanical dissociation of the respiratory system. These interventions, singly and in combination, partially restore more harmonious matching of excessive IND to ventilatory output achieved. In this review we propose, on the basis of a thorough review of the recent literature, that effective dyspnea amelioration requires combined interventions and a structured multidisciplinary approach, carefully tailored to meet the specific needs of the individual.

Effect of Vaporized Cannabis on Exertional Breathlessness and Exercise Endurance in Advanced Chronic Obstructive Pulmonary Disease. A Randomized Controlled Trial

RATIONALE

A series of studies conducted approximately 40 years ago demonstrated an acute bronchodilator effect of smoked cannabis in healthy adults and adults with asthma. However, the acute effects of vaporized cannabis on airway function in adults with advanced chronic obstructive pulmonary disease (COPD) remain unknown.

OBJECTIVES

To test the hypothesis that inhaled vaporized cannabis would alleviate exertional breathlessness and improve exercise endurance by enhancing static and dynamic airway function in COPD.

METHODS

In a randomized controlled trial of 16 adults with advanced COPD (forced expiratory volume in 1 second [FEV₁], mean ± SD: 36 ± 11% predicted), we compared the acute effect of 35 mg of inhaled vaporized cannabis (18.2% Δ⁹-tetrahydrocannabinol, <0.1% cannabidiol) versus 35 mg of a placebo control cannabis (CTRL; 0.33% Δ⁹-tetrahydrocannabinol, <0.99% cannabidiol) on physiological and perceptual responses during cardiopulmonary cycle endurance exercise testing; spirometry and impulse oscillometry at rest; and cognitive function, psychoactivity, and mood.

RESULTS

Compared with CTRL, cannabis had no effect on breathlessness intensity ratings during exercise at isotime (cannabis, 2.7 ± 1.2 Borg units vs. CTRL, 2.6 ± 1.3 Borg units); exercise endurance time (cannabis, 3.8 ± 1.9 min vs. CTRL, 4.2 ± 1.9 min); cardiac, metabolic, gas exchange, ventilatory, breathing pattern, and/or operating lung volume parameters at rest and during exercise; spirometry and impulse oscillometry-derived pulmonary function test parameters at rest; and cognitive function, psychoactivity, and mood.

CONCLUSIONS

Single-dose inhalation of vaporized cannabis had no clinically meaningful positive or negative effect on airway function, exertional breathlessness, and exercise endurance in adults with advanced COPD. Clinical trial registered with www.clinicaltrials.gov (NCT03060993).

The effect of carotid chemoreceptor inhibition on exercise tolerance in chronic obstructive pulmonary disease: A randomized-controlled crossover trial

BACKGROUND

Patients with chronic obstructive pulmonary disease (COPD) have an exaggerated ventilatory response to exercise, contributing to exertional dyspnea and exercise intolerance. We recently demonstrated enhanced activity and sensitivity of the carotid chemoreceptor (CC) in COPD which may alter ventilatory and cardiovascular regulation and negatively affect exercise tolerance. We sought to determine whether CC inhibition improves ventilatory and cardiovascular regulation, dyspnea and exercise tolerance in COPD.

METHODS

Twelve mild-moderate COPD patients (FEV₁ 83 ± 15 %predicted) and twelve age- and sex-matched healthy controls completed two time-to-symptom limitation (T_LIM) constant load exercise tests at 75% peak power output with either intravenous saline or low-dose dopamine (2 μg·kg^-1·min^-1, order randomized) to inhibit the CC. Ventilatory responses were evaluated using expired gas data and dyspnea was evaluated using a modified Borg scale. Inspiratory capacity maneuvers were performed to determine operating lung volumes. Cardiac output was estimated using impedance cardiography and vascular conductance was calculated as cardiac output/mean arterial pressure (MAP).

RESULTS

At a standardized exercise time of 4-min and at T_LIM; ventilation, operating volumes and dyspnea were unaffected by dopamine in COPD patients and controls. In COPD, dopamine decreased MAP and increased vascular conductance at all time points. In controls, dopamine increased vascular conductance at T_LIM, while MAP was unaffected.

CONCLUSION

There was no change in time to exhaustion in either group with dopamine. These data suggest that the CC plays a role in cardiovascular regulation during exercise in COPD; however, ventilation, dyspnea and exercise tolerance were unaffected by CC inhibition in COPD patients.

Physiological and perceptual responses to exercise according to locus of symptom limitation in COPD

Chronic obstructive pulmonary disease (COPD) is a heterogeneous disease, with pulmonary and extra-pulmonary factors contributing to exercise intolerance. The primary self-reported exercise-limiting symptom may reflect the primary pathophysiological factor contributing to exercise intolerance. We compared physiological and perceptual responses at the symptom-limited peak of incremental cardiopulmonary cycle exercise testing between people with COPD reporting breathlessness (B, n = 34), leg discomfort (LD, n = 16), or a combination of B and LD (BOTH, n = 42) as their main exercise-limiting symptom(s). Despite similarly impaired health status, symptomology and peak exercise capacity, the B group had greater restrictive constraints on tidal volume expansion at end-exercise and was more likely to report unpleasant qualities of exertional breathlessness than LD and BOTH groups. In conclusion, reporting breathlessness as the primary exercise-limiting symptom indicated the presence of distinct lung pathophysiology and symptom perception during exercise in people with COPD.

Prophylactic Fentanyl Sublingual Spray for Episodic Exertional Dyspnea in Cancer Patients: A Pilot Double-Blind Randomized Controlled Trial

CONTEXT

The optimal dose of fentanyl sublingual spray (FSS) for exertional dyspnea has not been determined.

OBJECTIVES

We examined the effect of two doses of prophylactic FSS on exertional dyspnea.

METHODS

In this parallel, dose-finding, double-blind randomized clinical trial, opioid-tolerant cancer patients completed a shuttle walk test at baseline. Patients completed a second shuttle walk test 10 minutes after a single dose of FSS equivalent to either 35%-45% (high dose) or 15%-25% (low dose) of the total daily opioid dose. The primary outcome was change in modified dyspnea Borg scale (0-10) between the first and second shuttle walk tests. Secondary outcomes included adverse events as well as changes in walk distance, vital signs, and neurocognitive function.

RESULTS

Thirty of the 50 enrolled patients completed the study. High-dose FSS (n = 13) resulted in significantly lower dyspnea (mean change -1.42; 95% CI -2.37, -0.48; P = 0.007) and greater walk distance (mean change 44 m; P = 0.001) compared to baseline. Low-dose FSS (n = 17) resulted in a nonsignificant reduction in dyspnea (mean change -0.47; 95% CI -1.26, 0.32; P = 0.24) and significant increase in walk distance (mean change 24 m; P = 0.01) compared to baseline. Global evaluation showed high-dose group was more likely to report at least somewhat better improvement (64% vs. 24%; P = 0.06). No significant adverse events or detriment to vital signs or neurocognitive function was detected.

CONCLUSION

Prophylactic FSS was well tolerated and demonstrated a dose-response relationship in improving both dyspnea and walk distance. High-dose FSS should be tested in confirmatory trials.

Effect of Prophylactic Fentanyl Buccal Tablet on Episodic Exertional Dyspnea: A Pilot Double-Blind Randomized Controlled Trial

CONTEXT

Episodic dyspnea is one of the most common, debilitating, and difficult-to-treat symptoms.

OBJECTIVE

We conducted a pilot study to examine the effect of prophylactic fentanyl buccal tablet (FBT) on exercise-induced dyspnea.

METHODS

In this parallel, double-blind randomized placebo-controlled trial, opioid-tolerant patients were asked to complete a six-minute walk test (6MWT) at baseline and then a second 6MWT 30 minutes after a single dose of FBT (equivalent to 20-50% of their total opioid dose) or matching placebo. We compared dyspnea Numeric Rating Scale (NRS, 0-10, primary outcome), walk distance, vital signs, neurocognitive function, and adverse events between the two 6MWTs.

RESULTS

Among 22 patients enrolled, 20 (91%) completed the study. FBT was associated with a significant within-arm reduction in dyspnea NRS between 0 and six minutes (mean change -2.4, 95% CI -3.5, -1.3) and respiratory rate (mean change -2.6, 95% CI -4.7, -0.4). Placebo was also associated with a nonstatistically significant decrease in dyspnea (mean change -1.1). Between-arm comparison of dyspnea scores in the second 6MWT favored FBT, albeit not statistically significant (estimate -0.25, P = 0.068). Global impression revealed more patients in the FBT group than placebo group reporting their dyspnea was at least "somewhat better" in the second 6MWT (4 of 9 vs. 0 of 11, P = 0.03). The other secondary outcomes did not differ significantly between arms.

CONCLUSIONS

This study supports that prophylactic FBT was associated with a reduction of exertional dyspnea and was well tolerated. Our findings support the need for larger trials to confirm the therapeutic potential of rapid-onset opioids.

Respiratory adverse effects of opioids for breathlessness: a systematic review and meta-analysis

Previous studies have shown that opioids can reduce chronic breathlessness in advanced disease. However, physicians remain reluctant to prescribe opioids for these patients, commonly due to fear of respiratory adverse effects. The aim of this study was to systematically review reported respiratory adverse effects of opioids in patients with advanced disease and chronic breathlessness.PubMed, Embase, the Cochrane Central Register of Controlled Trials, CINAHL, ClinicalTrials.gov and the reference lists of relevant systematic reviews were searched. Two independent researchers screened against predefined inclusion criteria and extracted data. Meta-analysis was conducted where possible.We included 63 out of 1990 articles, describing 67 studies. Meta-analysis showed an increase in carbon dioxide tension (0.27 kPa, 95% CI 0.08-0.45 kPa,) and no significant change in oxygen tension and oxygen saturation (both p>0.05). Nonserious respiratory depression (definition variable/not stated) was described in four out of 1064 patients. One cancer patient pretreated with morphine for pain needed temporary respiratory support following nebulised morphine for breathlessness (single case study).We found no evidence of significant or clinically relevant respiratory adverse effects of opioids for chronic breathlessness. Heterogeneity of design and study population, and low study quality are limitations. Larger studies designed to detect respiratory adverse effects are needed.

Effect of morphine on breathlessness and exercise endurance in advanced COPD: a randomised crossover trial

The objective of the present study was to evaluate the effect of morphine on exertional breathlessness and exercise endurance in advanced chronic obstructive pulmonary disease (COPD).

In a randomised crossover trial, we compared the acute effect of immediate-release oral morphineversusplacebo on physiological and perceptual responses during constant-load cardiopulmonary cycle exercise testing (CPET) in 20 adults with advanced COPD and chronic breathlessness syndrome.

Compared with placebo, morphine reduced exertional breathlessness at isotime by 1.2±0.4 Borg units and increased exercise endurance time by 2.5±0.9 min (both p≤0.014). During exercise at isotime, morphine decreased ventilation by 1.3±0.5 L·min−1and breathing frequency by 2.0±0.9 breaths·min−1(both p≤0.041). Compared with placebo, morphine decreased exertional breathlessness at isotime by ≥1 Borg unit in 11 participants (responders) and by <1 Borg unit in nine participants (non-responders). Baseline participant characteristics, including pulmonary function and cardiorespiratory fitness, were similar between responders and non-responders. A higher percentage of respondersversusnon-responders stopped incremental CPET due to intolerable breathlessness: 82versus33% (p=0.028).

Immediate-release oral morphine improved exertional breathlessness and exercise endurance in some, but not all, adults with advanced COPD. The locus of symptom-limitation on laboratory-based CPET may help to identify patients most likely to benefit from morphine.

Exertional dyspnoea in COPD: the clinical utility of cardiopulmonary exercise testing

Activity-related dyspnoea is often the most distressing symptom experienced by patients with chronic obstructive pulmonary disease (COPD) and can persist despite comprehensive medical management. It is now clear that dyspnoea during physical activity occurs across the spectrum of disease severity, even in those with mild airway obstruction. Our understanding of the nature and source of dyspnoea is incomplete, but current aetiological concepts emphasise the importance of increased central neural drive to breathe in the setting of a reduced ability of the respiratory system to appropriately respond. Since dyspnoea is provoked or aggravated by physical activity, its concurrent measurement during standardised laboratory exercise testing is clearly important. Combining measurement of perceptual and physiological responses during exercise can provide valuable insights into symptom severity and its pathophysiological underpinnings. This review summarises the abnormal physiological responses to exercise in COPD, as these form the basis for modern constructs of the neurobiology of exertional dyspnoea. The main objectives are: 1) to examine the role of cardiopulmonary exercise testing (CPET) in uncovering the physiological mechanisms of exertional dyspnoea in patients with mild-to-moderate COPD; 2) to examine the escalating negative sensory consequences of progressive respiratory impairment with disease advancement; and 3) to build a physiological rationale for individualised treatment optimisation based on CPET.

Advances in the Evaluation of Respiratory Pathophysiology during Exercise in Chronic Lung Diseases

Dyspnea and exercise limitation are among the most common symptoms experienced by patients with various chronic lung diseases and are linked to poor quality of life. Our understanding of the source and nature of perceived respiratory discomfort and exercise intolerance in chronic lung diseases has increased substantially in recent years. These new mechanistic insights are the primary focus of the current review. Cardiopulmonary exercise testing (CPET) provides a unique opportunity to objectively evaluate the ability of the respiratory system to respond to imposed incremental physiological stress. In addition to measuring aerobic capacity and quantifying an individual's cardiac and ventilatory reserves, we have expanded the role of CPET to include evaluation of symptom intensity, together with a simple "non-invasive" assessment of relevant ventilatory control parameters and dynamic respiratory mechanics during standardized incremental tests to tolerance. This review explores the application of the new advances in the clinical evaluation of the pathophysiology of exercise intolerance in chronic obstructive pulmonary disease (COPD), chronic asthma, interstitial lung disease (ILD) and pulmonary arterial hypertension (PAH). We hope to demonstrate how this novel approach to CPET interpretation, which includes a quantification of activity-related dyspnea and evaluation of its underlying mechanisms, enhances our ability to meaningfully intervene to improve quality of life in these pathologically-distinct conditions.

EffenDys-Fentanyl Buccal Tablet for the Relief of Episodic Breathlessness in Patients With Advanced Cancer: A Multicenter, Open-Label, Randomized, Morphine-Controlled, Crossover, Phase II Trial

CONTEXT

Episodic breathlessness is a frequent and burdensome symptom in cancer patients but pharmacological treatment is limited.

OBJECTIVES

To determine time to onset, efficacy, feasibility, and safety of transmucosal fentanyl in comparison to immediate-release morphine for the relief of episodic breathlessness.

METHODS

Phase II, investigator-initiated, multicenter, open-label, randomized, morphine-controlled, crossover trial with open-label titration of fentanyl buccal tablet (FBT) in inpatients with incurable cancer. The primary outcome was time to onset of meaningful breathlessness relief. Secondary outcomes were efficacy (breathlessness intensity difference at 10 and 30 minutes; sum of breathlessness intensity difference at 15 and 60 minutes), feasibility, and safety. Study was approved by local ethics committees.

RESULTS

Twenty-five of 1341 patients were eligible, 10 patients agreed to participate (four female, mean age 58 ± 11, mean Karnofsky score 67 ± 11). Two patients died before final visits and two patients dropped-out because of disease progression leaving six patients for analysis with 61 episodes of breathlessness. Mean time to onset was for FBT 12.7 ± 10.0 and for immediate-release morphine 23.6 ± 15.1 minutes with a mean difference of -10.9 minutes (95% CI = -24.5 to 2.7, P = 0.094). Efficacy measures were predominately in favor for FBT. Both interventions were safe. Feasibility failed because of too much study demands for a very ill patient group.

CONCLUSION

The description of a faster and greater relief of episodic breathlessness by transmucosal fentanyl versus morphine justifies further evaluation by a full-powered trial.

Impact of Prophylactic Fentanyl Pectin Nasal Spray on Exercise-Induced Episodic Dyspnea in Cancer Patients: A Double-Blind, Randomized Controlled Trial

CONTEXT

Episodic breathlessness is common and debilitating in cancer patients.

OBJECTIVES

In this pilot study, we examined the effect of prophylactic fentanyl pectin nasal spray (FPNS) on exercise-induced dyspnea, physiologic function, and adverse events.

METHODS

In this parallel, double-blind randomized placebo-controlled trial, opioid-tolerant patients performed three six-minute walk tests (6MWTs) to induce dyspnea. They were randomized to receive either FPNS (15%-25% of total daily opioid dose each time) or placebo 20 minutes before the second and third 6MWTs. We compared dyspnea Numeric Rating Scale (NRS, 0-10, primary outcome), walk distance, vital signs, neurocognitive function, and adverse events between the first and second 6MWTs (T2-T1) and between the first and third 6MWTs (T3-T1).

RESULTS

Twenty-four patients enrolled, with 96% completion. FPNS was associated with significant within-arm reduction in dyspnea NRS at rest (T2-T1: -0.9 [95% CI -1.7, -0.1]; T3-T1: -1.3 [95% CI -2.0, -0.5]) and at the end of a 6MWT (T2-T1: -2.0 [95% CI -3.5, -0.6]; T3-T1: -2.3 [95% CI -4.0, -0.7]), and longer walk distance (T2-T1 +23.8 m [95% CI +1.3, +46.2 m]; T3-T1: +23.3 m [95% CI -1.7, +48.2]). In the placebo arm, we observed no significant change in walk distance nor dyspnea NRS at rest, but significant reduction in dyspnea NRS at six minutes (T2-T1: -1.7 [95% CI -3.3, -0.1]; T3-T1: -2.5 [95% CI -4.2, -0.9]). Vital signs, neurocognitive function, and adverse effects did not differ significantly.

CONCLUSION

FPNS was safe, reduced dyspnea at rest, and increased walk distance in before-after comparison. The placebo effect was substantial, which needs to be factored in future study designs.

TRIAL REGISTRATION

ClinicalTrials.govNCT01832402.

Skeletal muscle power and fatigue at the tolerable limit of ramp-incremental exercise in COPD

Muscle fatigue (a reduced power for a given activation) is common following exercise in chronic obstructive pulmonary disease (COPD). Whether muscle fatigue, and reduced maximal voluntary locomotor power, are sufficient to limit whole body exercise in COPD is unknown. We hypothesized in COPD: 1) exercise is terminated with a locomotor muscle power reserve; 2) reduction in maximal locomotor power is related to ventilatory limitation; and 3) muscle fatigue at intolerance is less than age-matched controls. We used a rapid switch from hyperbolic to isokinetic cycling to measure the decline in peak isokinetic power at the limit of incremental exercise ("performance fatigue") in 13 COPD patients (FEV₁ 49 ± 17%pred) and 12 controls. By establishing the baseline relationship between muscle activity and isokinetic power, we apportioned performance fatigue into the reduction in muscle activation and muscle fatigue. Peak isokinetic power at intolerance was ~130% of peak incremental power in controls (274 ± 73 vs. 212 ± 84 W, P < 0.05), but ~260% in COPD patients (187 ± 141 vs. 72 ± 34 W, P < 0.05), greater than controls (P < 0.05). Muscle fatigue as a fraction of baseline peak isokinetic power was not different in COPD patients vs. controls (0.11 ± 0.20 vs. 0.19 ± 0.11). Baseline to intolerance, the median frequency of maximal isokinetic muscle activity, was unchanged in COPD patients but reduced in controls (+4.3 ± 11.6 vs. -5.5 ± 7.6%, P < 0.05). Performance fatigue as a fraction of peak incremental power was greater in COPD vs. controls and related to resting (FEV₁/FVC) and peak exercise (V̇_E/maximal voluntary ventilation) pulmonary function (r² = 0.47 and 0.55, P < 0.05). COPD patients are more fatigable than controls, but this fatigue is insufficient to constrain locomotor power and define exercise intolerance.

Nebulized Fentanyl in Acute Pain: A Systematic Review

OBJECTIVE

To provide a systematic review of the current role of nebulized fentanyl in acute pain and potentially other conditions.

DATA SOURCES

A MEDLINE literature search inclusive of the dates 1946 to May 2016 was performed using the following search terms: fentanyl and administration, inhaled Excerpta Medica was searched from 1980 to May 2016 using the following search terms: exp fentanyl/inhalation drug administration Additionally, Web of Science was searched using the terms fentanyl and pain inclusive of 1945 to May 2016.

STUDY SELECTION AND DATA EXTRACTION

We utilized the Preferred Reporting Items for Systematic Reviews and Meta-analyses (PRISMA) guidelines to select English language, human primary literature, review articles, and supporting data assessing the efficacy of nebulized fentanyl in acute pain.

DATA SYNTHESIS

Seven clinical trials have demonstrated no difference in efficacy between nebulized fentanyl and intravenous (IV) opioids. Few adverse effects were reported; however, the trials were of short duration. Nebulized fentanyl appeared to be a rapid-acting analgesic that does not require IV access.

CONCLUSION

Evidence suggests that nebulized fentanyl is as effective as IV opioids in the treatment of acute pain, with relatively few adverse effects. However, questions remain about the extemporaneous preparation of fentanyl nebulized solution, the variability in nebulization devices, and ensuring consistent drug delivery to distal airways in the clinical setting. The abuse potential of nebulized fentanyl should also be considered.

Opioids for the palliation of refractory breathlessness in adults with advanced disease and terminal illness

BACKGROUND

Breathlessness is a common and disabling symptom which affects many people with advanced cardiorespiratory disease and cancer. The most effective treatments are aimed at treating the underlying disease. However, this may not always be possible, and symptomatic treatment is often required in addition to maximal disease-directed therapy. Opioids are increasingly being used to treat breathlessness, although their mechanism of action is still not completely known. A few good sized, high quality trials have been conducted in this area.

OBJECTIVES

To determine the effectiveness of opioid drugs in relieving the symptom of breathlessness in people with advanced disease due to malignancy, respiratory or cardiovascular disease, or receiving palliative care for any other disease.

SEARCH METHODS

We performed searches on CENTRAL, MEDLINE, EMBASE, CINAHL, and Web of Science up to 19 October 2015. We handsearched review articles, clinical trial registries, and reference lists of retrieved articles.

SELECTION CRITERIA

We included randomised double-blind controlled trials that compared the use of any opioid drug against placebo or any other intervention for the relief of breathlessness. The intervention was any opioid, given by any route, in any dose.

DATA COLLECTION AND ANALYSIS

We imported studies identified by the search into a reference manager database. We retrieved the full-text version of relevant studies, and two review authors independently extracted data. The primary outcome measure was breathlessness and secondary outcome measures included exercise tolerance, oxygen saturations, adverse events, and mortality. We analysed all studies together and also performed subgroup analyses, by route of administration, type of opioid administered, and cause of breathlessness. Where appropriate, we performed meta-analysis. We assessed the evidence using the Grading of Recommendations Assessment, Development and Evaluation (GRADE) approach and created three 'Summary of findings' tables.

MAIN RESULTS

We included 26 studies with 526 participants. We assessed the studies as being at high or unclear risk of bias overall. We only included randomised controlled trials (RCTs), although the description of randomisation was incomplete in some included studies. We aimed to include double blind RCTs, but two studies were only single blinded. There was inconsistency in the reporting of outcome measures. We analysed the data using a fixed-effect model, and for some outcomes heterogeneity was high. There was a risk of imprecise results due to the low numbers of participants in the included studies. For these reasons we downgraded the quality of the evidence from high to either low or very low.For the primary outcome of breathlessness, the mean change from baseline dyspnoea score was 0.09 points better in the opioids group compared to the placebo group (ranging from a 0.36 point reduction to a 0.19 point increase) (seven RCTs, 117 participants, very low quality evidence). A lower score indicates an improvement in breathlessness. The mean post-treatment dyspnoea score was 0.28 points better in the opioid group compared to the placebo group (ranging from a 0.5 point reduction to a 0.05 point increase) (11 RCTs, 159 participants, low quality evidence).The evidence for the six-minute walk test (6MWT) was conflicting. The total distance in 6MWT was 28 metres (m) better in the opioids group compared to placebo (ranging from 113 m to 58 m) (one RCT, 11 participants, very low quality evidence). However, the change in baseline was 48 m worse in the opioids group (ranging from 36 m to 60 m) (two RCTs, 26 participants, very low quality evidence).The adverse effects reported included drowsiness, nausea and vomiting, and constipation. In those studies, participants were 4.73 times more likely to experience nausea and vomiting compared to placebo, three times more likely to experience constipation, and 2.86 times more likely to experience drowsiness (nine studies, 162 participants, very low quality evidence).Only four studies assessed quality of life, and none demonstrated any significant change.

AUTHORS' CONCLUSIONS

There is some low quality evidence that shows benefit for the use of oral or parenteral opioids to palliate breathlessness, although the number of included participants was small. We found no evidence to support the use of nebulised opioids. Further research with larger numbers of participants, using standardised protocols and with quality of life measures included, is needed.

Opioids: an unexplored option for treatment of dyspnea in IPF

BACKGROUND

Idiopathic pulmonary fibrosis (IPF) is the most common among the idiopathic interstitial pneumonias and has the worst prognosis, with a median survival of 3-5 years. The most common symptom in IPF is dyspnea, impacting on the patient's quality of life and life expectancy. Morphine in the treatment of dyspnea has been investigated but with conflicting results. This review aims to clarify the role of opioids in the treatment of dyspnea in patients with IPF.

METHODS

A literature search was performed using the MeSH and PubMed databases. As only very few studies included patients with IPF, studies conducted primarily with patients with chronic obstructive pulmonary disease were also included. In total, 14 articles were found.

RESULTS

Seven studies reported use of systemic morphine and seven studies of inhaled morphine. Five of the seven studies investigating systemic administration detected an improvement in either dyspnea or exercise capacity, whereas no beneficial effect on dyspnea was detected in any study using inhaled morphine. No severe adverse effects such as respiratory depression were reported in any study, although constipation was reported as a notable adverse effect.

CONCLUSIONS

Results were inconsistent, but in some studies systemic morphine administration showed a significant improvement in the dyspnea score on a visual analog scale without observation of severe side effects. Nebulized morphine had no effect on dyspnea.

Epidemiology and Characteristics of Episodic Breathlessness in Advanced Cancer Patients: An Observational Study

CONTEXT

Episodic breathlessness is a relevant aspect in patients with advanced cancer.

OBJECTIVES

The aim of this study was to assess the different aspects of this clinical phenomenon.

METHODS

A consecutive sample of patients with advanced cancer admitted to different settings for a period of six months was surveyed. The presence of background breathlessness and episodic breathlessness, their intensity (numerical scale 0-10), and drugs used for treatment were collected. Factors inducing episodic breathlessness and its influence on daily activities were investigated.

RESULTS

Of 921 patients, 29.3% (n = 269) had breathlessness and 134 patients (49.8%) were receiving drugs for background breathlessness. In the multivariate analysis, the risk of breathlessness increased with chronic obstructive pulmonary disease, although it decreased in patients receiving disease-oriented therapy and patients with gastrointestinal tumors. The prevalence of episodic breathlessness was 70.9% (n = 188), and its mean intensity was 7.1 (SD 1.6). The mean duration of untreated episodic breathlessness was 19.9 minutes (SD 35.3); 41% of these patients were receiving drugs for episodic breathlessness. The majority of episodic breathlessness events (88.2%) were triggered by activity. In the multivariate analysis, higher Karnofsky Performance Status levels were significantly related to episodic breathlessness, although patients receiving disease-oriented therapy were less likely to have episodic breathlessness.

CONCLUSION

This study showed that episodic breathlessness frequently occurs in patients with breathlessness in the advanced stage of disease, has a severe intensity, and is characterized by rapid onset and short duration, which require rapid measures.

Recent advances in dyspnea

Dyspnea is the most prevalent symptom among patients with cardiac and respiratory diseases. It is an independent predictor of mortality in patients with heart disease, COPD, and the elderly. Studies using naloxone to block opioid-receptor signaling demonstrate that endogenous opioids modulate dyspnea in patients with COPD. Neuroimaging studies support a cortical-limbic network for dyspnea perception. A 2012 American Thoracic Society statement recommended that dyspnea be considered across three different constructs: sensory (intensity), affective (distress), and impact on daily activities. The 2013 GOLD (Global Initiative for Chronic Obstructive Lung Disease) executive summary recommended a treatment paradigm for patients with COPD based on the modified Medical Research Council dyspnea score. The intensity and quality of dyspnea during exercise in patients with COPD is influenced by the time to onset of critical mechanical volume constraints that are ultimately dictated by the magnitude of resting inspiratory capacity. Long-acting bronchodilators, either singly or in combination, provide sustained bronchodilation and lung deflation that contribute to relief of dyspnea in those with COPD. Opioid medications reduce breathing discomfort by decreasing respiratory drive (and associated corollary discharge), altering central perception, and/or decreasing anxiety. For individuals suffering from refractory dyspnea, a low dose of an opioid is recommended initially, and then titrated to achieve the lowest effective dose based on patient ratings. Acupuncture, bronchoscopic volume reduction, and noninvasive open ventilation are experimental approaches shown to ameliorate dyspnea in patients with COPD, but require confirmatory evidence before clinical use.

Attitudes toward opioids for refractory dyspnea in COPD among Dutch chest physicians

Dyspnea is the most frequently reported symptom of outpatients with advanced chronic obstructive pulmonary disease (COPD). Opioids are an effective treatment for dyspnea. Nevertheless, the prescription of opioids to patients with advanced COPD seems limited. The aims of this study are to explore the attitudes of Dutch chest physicians toward prescription of opioids for refractory dyspnea to outpatients with advanced COPD and to investigate the barriers experienced by chest physicians toward opioid prescription in these patients. All chest physicians (n = 492) and residents in respiratory medicine (n = 158) in the Netherlands were invited by e-mail to complete an online survey. A total of 146 physicians (response rate 22.5%) completed the online survey. Fifty percent of the physicians reported to prescribe opioids for refractory dyspnea in 20% or less of their outpatients with advanced COPD and 18.5% reported never to prescribe opioids in these patients. The most frequently reported barriers toward prescription of opioids were resistance of the patient, fear of possible adverse effects, and fear of respiratory depression. To conclude, Dutch chest physicians and residents in respiratory medicine rarely prescribe opioids for refractory dyspnea to outpatients with advanced COPD. This reluctance is caused by perceived resistance of the patient and fear of adverse effects, including respiratory adverse effects.

Intravenous Fentanyl for Dyspnea at the End of Life: Lessons for Future Research in Dyspnea

OBJECTIVES

To determine the efficacy of intravenous (IV) Fentanyl in dyspnoeic patients with advanced cancer.

METHODS

Dyspnoeic patients with advanced cancer satisfying the selection criteria received (IV) Fentanyl and were evaluated for response 24 hours post-administration in a prospective observational study.

RESULTS

Altogether 36 patients were enrolled into the study. However, data from only 16 patients could be analysed as 20 patients had died or were too sick to self-report scores. Seven out of 16 patients responded to IV Fentanyl although the result was not statistically significant (non-responders versus responders: 56.3% vs 43.8%, p = 0.33). The strongest correlations for variables predictive of responder status were the absence of anxiety and lung metastases.

CONCLUSIONS

This exploratory study shows that IV Fentanyl can alleviate dyspnea in some patients but is an example of the difficulties conducting dyspnea research. Future studies would benefit from novel developments in the areas of measuring dyspnea in dying patients and statistical analysis of small sample sizes.

Opioids, Exertion, and Dyspnea

The aim of this paper is to review the evidence for a role for opioids as an intervention for exertion induced breathlessness with regard to exercise tolerance and breathlessness intensity. Current knowledge about exogenous opioids in exertion-induced breathlessness due to disease comes from a variety of phase 2 feasibility or pilot designs with differing duration, doses, drugs, exercise regimes, underlying aetiologies, and outcome measures. They provide interesting data but firm conclusions for either breathlessness severity or exercise endurance cannot be drawn. There are no adequately powered phase 3 trials of opioids which show improved exercise tolerance and/or exertion induced breathlessness. Low dose oral morphine seems well tolerated by most, and is beneficial for breathlessness intensity. Current work to investigate the effect on exercise tolerance is ongoing.