Effects of dihydrocodeine, alcohol, and caffeine on breathlessness and exercise tolerance in patients with chronic obstructive lung disease and normal blood gases

Recent discoveries from clinical trials: why opioids should not be used for dyspnea management in COPD

INTRODUCTION

Chronic breathlessness among persons with chronic obstructive pulmonary disease (COPD) is a distressing and limiting symptom and a substantial management challenge for healthcare practitioners. Historically, multiple professional respiratory societies have encouraged the prescription of opioid drugs as a therapeutic intervention for chronic breathlessness. However, in 2024, the European Respiratory Society (ERS) published clinical practice guidelines that markedly departed from such traditional recommendations and stated that opioids should not be used for chronic breathlessness.

AREAS COVERED

This manuscript will review recently published, well-designed, randomized controlled trials (literature was searched on PubMed from January 2020 to January 2025) that evaluated the efficacy of oral opioids for chronic breathlessness in persons with COPD and which influenced the new position adopted by ERS in 2024.

EXPERT OPINION

Recent, well-designed, adequately powered clinical trials consistently demonstrate that oral opioids are not effective at reducing chronic breathlessness (nor at improving overall quality of life, functional status or exercise tolerance) amongst individuals with advanced COPD. Other professional respiratory societies need to consider and potentially embrace the new ERS position on opioids for dyspnea in COPD, so as to guide members away from an unhelpful, and in some cases harmful, management paradigm.

Opioids for the palliation of symptoms in people with serious respiratory illness: a systematic review and meta-analysis

BACKGROUND

People living with serious respiratory illness experience a high burden of distressing symptoms. Although opioids are prescribed for symptom management, they generate adverse events, and their benefits are unclear.

METHODS

We examined the efficacy and safety of opioids for symptom management in people with serious respiratory illness. Embase, MEDLINE and the Cochrane Central Register of Controlled Trials were searched up to 11 July 2022. Reports of randomised controlled trials administering opioids to treat symptoms in people with serious respiratory illness were included. Key exclusion criteria included <80% of participants having a nonmalignant lung disease. Data were extracted regarding study characteristics, outcomes of breathlessness, cough, health-related quality of life (HRQoL) and adverse events. Treatment effects were pooled using a generic inverse variance model with random effects. Risk of bias was assessed using the Cochrane Risk of Bias tool version 1.

RESULTS

Out of 17 included trials, six were laboratory-based exercise trials (n=70), 10 were home studies measuring breathlessness in daily life (n=788) and one (n=18) was conducted in both settings. Overall certainty of evidence was "very low" to "low". Opioids reduced breathlessness intensity during laboratory exercise testing (standardised mean difference (SMD) -0.37, 95% CI -0.67- -0.07), but not breathlessness measured in daily life (SMD -0.10, 95% CI -0.64-0.44). No effects on HRQoL (SMD -0.42, 95% CI -0.98-0.13) or cough (SMD -1.42, 95% CI -3.99-1.16) were detected. In at-home studies, opioids led to increased frequency of nausea/vomiting (OR 3.32, 95% CI 1.70-6.51), constipation (OR 3.08, 95% CI 1.69-5.61) and drowsiness (OR 1.37, 95% CI 1.01-1.86), with serious adverse events including hospitalisation and death identified.

CONCLUSIONS

Opioids improved exertional breathlessness in laboratory exercise studies, but did not improve breathlessness, cough or HRQoL measured in daily life at home. There were significant adverse events, which may outweigh any benefits.

European Respiratory Society clinical practice guideline on symptom management for adults with serious respiratory illness

Respiratory symptoms are ubiquitous and impair health-related quality of life in people with respiratory disease. This European Respiratory Society (ERS) task force aimed to provide recommendations for symptomatic treatment in people with serious respiratory illness. The ERS task force comprised 16 members, including representatives of people with serious respiratory illness and informal caregivers. Seven questions were formulated, six in the PICO (Population, Intervention, Comparison, Outcome) format, which were addressed with full systematic reviews and evidence assessed using GRADE (Grading of Recommendations Assessment, Development and Evaluation). One question was addressed narratively. An "evidence-to-decision" framework was used to formulate recommendations. To treat symptoms in people with serious respiratory illness, the task force suggests the use of graded exercise therapy (conditional recommendation, low certainty of evidence); and suggests the use of a multicomponent services, handheld fan and breathing techniques (conditional recommendations, very low certainty of evidence). The task force suggests not to use opioids (conditional recommendation, very low certainty of evidence); and suggests either administering or not administering supplemental oxygen therapy (conditional recommendation, low certainty of evidence). The task force suggests that needs assessment tools may be used as part of a comprehensive needs assessment, but do not replace patient-centred care and shared decision making (conditional recommendation, low certainty of evidence). The low certainty of evidence, modest impact of interventions on patient-centred outcomes, and absence of effective strategies to ameliorate cough highlight the need for new approaches to reduce symptoms and enhance wellbeing for individuals who live with serious respiratory illness.

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.

COVID-19, Suffering and Palliative Care: A Review

According to the WHO guideline, palliative care is an integral component of COVID-19 management. The relief of physical symptoms and the provision of psychosocial support should be practiced by all healthcare workers caring for COVID-19 patients. In this review, we aim to provide a simple outline on COVID-19, suffering in COVID-19, and the role of palliative care in COVID-19. We also introduce 3 principles of palliative care that can serve as a guide for all healthcare workers caring for COVID-19 patients, which are (1) good symptom control, (2) open and sensitive communication, and (3) caring for the whole team. The pandemic has brought immense suffering, fear and death to people everywhere. The knowledge, skills and experiences from palliative care could be used to relieve the suffering of COVID-19 patients.

Opioid Prescription Method for Breathlessness Due to Non-Cancer Chronic Respiratory Diseases: A Systematic Review

A previous pooled analysis demonstrated significant relief of breathlessness following opioid administration in patients with chronic obstructive pulmonary disease. However, in clinical practice, it is important to know the characteristics of patients responding to opioids, the best prescription methods, and the evaluation measures that can sufficiently reflect these effects. Thus, we performed a systematic review of systemic opioids for non-cancer chronic respiratory diseases. Fifteen randomized controlled studies (RCTs), four non-randomized studies, two observational studies, and five retrospective studies were included. Recent RCTs suggested that regular oral opioid use would decrease the worst breathlessness in patients with a modified Medical Research Council score ≥ 3 by a degree of 1.0 or less on a scale of 1–10. Ergometer or treadmill tests indicated mostly consistent significant acute effects of morphine or codeine. In two non-randomized studies, about 60% of patients responded to opioids and showed definite improvement in symptoms and quality of life. Furthermore, titration of opioids in these studies suggested that a major proportion of these responders had benefits after administration of approximately 10 mg/day of morphine. However, more studies are needed to clarify the prescription method to reduce withdrawal due to adverse effects, which would lead to significant improvements in overall well-being.

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.

Multiple potential targets of opioids in the treatment of acute respiratory distress syndrome from COVID-19

COVID-19 can present with a variety of clinical features, ranging from asymptomatic or mild respiratory symptoms to fulminant acute respiratory distress syndrome (ARDS) depending on the host's immune responses and the extent of the associated pathologies. This implies that several measures need to be taken to limit severely impairing symptoms caused by viral-induced pathology in vital organs. Opioids are most exploited for their analgesic effects but their usage in the palliation of dyspnoea, immunomodulation and lysosomotropism may represent potential usages of opioids in COVID-19. Here, we describe the mechanisms involved in each of these potential usages, highlighting the benefits of using opioids in the treatment of ARDS from SARS-CoV-2 infection.

Use of short-acting opioids in the management of breathlessness: an evidence-based review

PURPOSE OF REVIEW

To provide an evidence-based review on the use of short-acting opioids for management of breathlessness in patients with advanced diseases.

RECENT FINDINGS

We identified 28 randomized controlled trials that examined the effect of short-acting opioids on breathlessness under three study settings: as a prophylactic dose given prior to exertion; as a rescue dose for treatment of breathlessness at rest or episodic breathlessness; or as a scheduled medication for overall reduction of breathlessness. These trials varied widely in regard to patient population (opioid naive or tolerant), opioid (formulation, dose, timing of administration, and scheduling) and control intervention. Taken together, there is good evidence to support that short-acting opioids can reduce breathlessness and improve activity level when given before exertion. There is some evidence that parenteral opioids are efficacious for the as needed treatment of episodic breathlessness or breathlessness at rest. However, there is only limited evidence to support scheduled short-acting opioids for overall relief of breathlessness.

SUMMARY

There is evidence to support that short-acting opioids have a pharmacologic effect on breathlessness. More research is needed to clarify how opioids can be prescribed to optimize breathlessness relief, function, and quality of life.

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.

COVID-19: Pain Management in Patients with SARS-CoV-2 Infection-Molecular Mechanisms, Challenges, and Perspectives

Since the end of 2019, the whole world has been struggling with the pandemic of the new Severe Acute Respiratory Syndrome Coronavirus (SARS-CoV-2). Available evidence suggests that pain is a common symptom during Coronavirus Disease 2019 (COVID-19). According to the World Health Organization, many patients suffer from muscle pain (myalgia) and/or joint pain (arthralgia), sore throat and headache. The exact mechanisms of headache and myalgia during viral infection are still unknown. Moreover, many patients with respiratory failure get admitted to the intensive care unit (ICU) for ventilatory support. Pain in ICU patients can be associated with viral disease itself (myalgia, arthralgia, peripheral neuropathies), may be caused by continuous pain and discomfort associated with ICU treatment, intermittent procedural pain and chronic pain present before admission to the ICU. Undertreatment of pain, especially when sedation and neuromuscular blocking agents are used, prone positioning during mechanical ventilation or extracorporeal membrane oxygenation (ECMO) may trigger delirium and cause peripheral neuropathies. This narrative review summarizes current knowledge regarding challenges associated with pain assessment and management in COVID-19 patients. A structured prospective evaluation should be undertaken to analyze the probability, severity, sources and adequate treatment of pain in patients with COVID-19 infection.

Effects of morphine on respiratory load detection, load magnitude perception, and tactile sensation in obstructive sleep apnea

Pharyngeal and respiratory sensation is impaired in obstructive sleep apnea (OSA). Opioids may further diminish respiratory sensation. Thus protective pharyngeal neuromuscular and arousal responses to airway occlusion that rely on respiratory sensation could be impaired with opioids to worsen OSA severity. However, little is known about the effects of opioids on upper airway and respiratory sensation in people with OSA. This study was designed to determine the effects of 40 mg of MS-Contin on tactile sensation, respiratory load detection, and respiratory magnitude perception in people with OSA during wakefulness. A double-blind, randomized, crossover design (1 wk washout) was used. Twenty-one men with untreated OSA (apnea/hypopnea index = 26 ± 17 events/h) recruited from a larger clinical study completed the protocol. Tactile sensation using von Frey filaments on the back of the hand, internal mucosa of the cheek, uvula, and posterior pharyngeal wall were not different between placebo and morphine [e.g., median (interquartile range) posterior wall = 0.16 (0.16, 0.4) vs. 0.4 (0.14, 1.8) g, P = 0.261]. Similarly, compared with placebo, morphine did not alter respiratory load detection thresholds for nadir mask pressure detected = −2.05 (−3.37, −1.55) vs. −2.19 (−3.36, −1.41) cmH2O, P = 0.767], or respiratory load magnitude perception [mean ± SD Borg scores during a 5 resistive load (range: 5–126 cmH2O·l−1·s−1) protocol = 4.5 ± 1.6 vs. 4.2 ± 1.2, P = 0.347] but did reduce minute ventilation during quiet breathing (11.4 ± 3.3 vs. 10.7 ± 2.6 l/min, P < 0.01). These findings indicate that 40 mg of MS-Contin does not systematically impair tactile or respiratory sensation in men with mild to moderate, untreated OSA. This suggests that altered respiratory sensation to acute mechanical stimuli is not likely to be a mechanism that contributes to worsening of OSA with a moderate dose of morphine.

NEW & NOTEWORTHY Forty milligrams of MS-Contin does not alter upper airway tactile sensation, respiratory load detection thresholds, or respiratory load magnitude perception in people with obstructive sleep apnea but does decrease breathing compared with placebo during wakefulness. Despite increasing concerns of harm with opioids, the current findings suggest that impaired respiratory sensation to acute mechanical stimuli with this dose of MS-Contin is unlikely to be a direct mechanism contributing to worsening sleep apnea severity in people with mild-to-moderate disease.

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 morphine versus placebo 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-1 and 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 responders versus non-responders stopped incremental CPET due to intolerable breathlessness: 82 versus 33% (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.

Benzodiazepines for the relief of breathlessness in advanced malignant and non-malignant diseases in adults

BACKGROUND

This is an updated version of the original Cochrane review published in Issue 1, 2010, on 'Benzodiazepines for the relief of breathlessness in advanced malignant and non-malignant diseases in adults'. Breathlessness is one of the most common symptoms experienced in the advanced stages of malignant and non-malignant disease. Benzodiazepines are widely used for the relief of breathlessness in advanced diseases and are regularly recommended in the literature. At the time of the previously published Cochrane review, there was no evidence for a beneficial effect of benzodiazepines for the relief of breathlessness in people with advanced cancer and chronic obstructive pulmonary disease (COPD).

OBJECTIVES

The primary objective of this review was to determine the efficacy of benzodiazepines for the relief of breathlessness in people with advanced disease. Secondary objectives were to determine the efficacy of different benzodiazepines, different doses of benzodiazepines, different routes of application, adverse effects of benzodiazepines, and the efficacy in different disease groups.

SEARCH METHODS

This is an update of a review published in 2010. We searched 14 electronic databases up to September 2009 for the original review. We checked the reference lists of all relevant studies, key textbooks, reviews, and websites. For the update, we searched CENTRAL, MEDLINE, and EMBASE and registers of clinical trials for further ongoing or unpublished studies, up to August 2016. We contacted study investigators and experts in the field of palliative care asking for further studies, unpublished data, or study details when necessary.

SELECTION CRITERIA

We included randomised controlled trials (RCTs) and controlled clinical trials (CCTs) assessing the effect of benzodiazepines compared with placebo or active control in relieving breathlessness in people with advanced stages of cancer, chronic obstructive pulmonary disease (COPD), chronic heart failure (CHF), motor neurone disease (MND), and idiopathic pulmonary fibrosis (IPF).

DATA COLLECTION AND ANALYSIS

Two review authors independently assessed identified titles and abstracts. Three review authors independently performed assessment of all potentially relevant studies (full text), data extraction, and assessment of methodological quality. We carried out meta-analysis where appropriate.

MAIN RESULTS

Overall, we identified eight studies for inclusion: seven in the previous review and an additional study for this update. We also identified two studies awaiting classification in this update. The studies were small (a maximum number of 101 participants) and comprised data from a total of 214 participants with advanced cancer or COPD, which we analysed. There was only one study of low risk of bias. Most of the studies had an unclear risk of bias due to lack of information on random sequence generation, concealment, and attrition. Analysis of all studies did not show a beneficial effect of benzodiazepines for the relief of breathlessness (the primary outcome) in people with advanced cancer and COPD (8 studies, 214 participants) compared to placebo, midazolam, morphine, or promethazine. Furthermore, we observed no statistically significant effect in the prevention of episodic breathlessness (breakthrough dyspnoea) in people with cancer (after 48 hours: risk ratio of 0.76 (95% CI 0.53 to 1.09; 2 studies, 108 participants)) compared to morphine. Sensitivity analyses demonstrated no statistically significant differences regarding type of benzodiazepine, dose, route and frequency of delivery, duration of treatment, or type of control. Benzodiazepines caused statistically significantly more adverse events, particularly drowsiness and somnolence, when compared to placebo (risk difference 0.74 (95% CI 0.37, 1.11); 3 studies, 38 participants). In contrast, two studies reported that morphine caused more adverse events than midazolam (RD -0.18 (95% CI -0.31, -0.04); 194 participants).

AUTHORS' CONCLUSIONS

Since the last version of this review, we have identified one new study for inclusion, but the conclusions remain unchanged. There is no evidence for or against benzodiazepines for the relief of breathlessness in people with advanced cancer and COPD. Benzodiazepines caused more drowsiness as an adverse effect compared to placebo, but less compared to morphine. Benzodiazepines may be considered as a second- or third-line treatment, when opioids and non-pharmacological measures have failed to control breathlessness. There is a need for well-conducted and adequately powered studies.

Opioids for management of episodic breathlessness or dyspnea in patients with advanced disease

BACKGROUND

Episodic breathlessness (EB) or dyspnea is a common symptom with a very negative impact on the quality of life of patients with cancer and with non-oncological advanced diseases, mainly cardiorespiratory and neurological.

OBJECTIVE

The purpose of this non-systematic review is to ascertain the role played by opioids in the management of episodic breathlessness.

METHODS

A non-systematic literature review was done in the databases MEDLINE, COCHRANE, and DATABASE, and articles of greater scientific rigor, mainly reviews or prospective studies/randomized clinical trials published to date (August 2015), were selected. Terms used in the search included episodic breathlessness, acute breathlessness, episodic dyspnea, opioids, morphine, fentanyl, oxycodone, and breakthrough dyspnea.

CONCLUSIONS

Although the pathophysiology and mechanism of action of opioids for management of breathlessness, and specifically EB, are not fully known, there is scientific evidence, and particularly great clinical evidence, of the benefit of this drug class for dyspnea management. It is important to differentiate hospitalized patients from outpatients because venous or subcutaneous access is easier in hospitalized patients, but use of transmucosal fentanyl, especially in faster formulations like intranasal application, opens up new possibilities to manage outpatients due to its fast onset of action. The main problem is the lack of data available and the multitude of unanswered questions about opioid type, administration route, safety, and dose titration.

Incident opioid drug use and adverse respiratory outcomes among older adults with COPD

We evaluated risk of adverse respiratory outcomes associated with incident opioid use among older adults with chronic obstructive pulmonary diseases (COPD).

This was a retrospective population-based cohort study using a validated algorithm applied to health administrative data to identify adults aged 66 years and older with COPD. Inverse probability of treatment weighting using the propensity score was used to estimate hazard ratios comparing adverse respiratory outcomes within 30 days of incident opioid use compared to controls.

Incident opioid use was associated with significantly increased emergency room visits for COPD or pneumonia (HR 1.14, 95% CI 1.00–1.29; p=0.04), COPD or pneumonia-related mortality (HR 2.16, 95% CI 1.61–2.88; p<0.0001) and all-cause mortality (HR 1.76, 95% CI 1.57–1.98; p<0.0001), but significantly decreased outpatient exacerbations (HR 0.88, 95% CI 0.83–0.94; p=0.0002). Use of more potent opioid-only agents was associated with significantly increased outpatient exacerbations, emergency room visits and hospitalisations for COPD or pneumonia, and COPD or pneumonia-related and all-cause mortality.

Incident opioid use, and in particular use of the generally more potent opioid-only agents, was associated with increased risk for adverse respiratory outcomes, including respiratory-related mortality, among older adults with COPD. Potential adverse respiratory outcomes should be considered when prescribing new opioids in this population.

Treatment Recommendations for Respiratory Symptoms in Cancer Patients: Clinical Guidelines from the Japanese Society for Palliative Medicine

BACKGROUND

Respiratory symptoms, dyspnea, cough, and death rattle, are common and distressing in advanced cancer patients. Palliation of respiratory symptoms is important to improve quality of life in cancer patients and their families/caregivers. Currently published clinical guidelines for the management of these respiratory symptoms in cancer patients did not cover the topics comprehensively or were not based on formal process for the development of clinical guidelines.

METHODS

The Japanese Society for Palliative Medicine (JSPM) decided to develop comprehensive clinical guidelines for the management of respiratory symptoms in cancer patients following the formal guideline developing process.

RESULTS

This article provides a summary of the recommendations with the rationales, as well as a short summary of the developing process, of the JSPM respiratory symptom management guidelines. We established 26 recommendations and all recommendations are based on the best available evidences and expert consensus.

DISCUSSION

More future clinical researches and continuous guideline updates are required to improve the quality of respiratory symptom management in cancer patients.

Pharmacological management of breathlessness in COPD: recent advances and hopes for the future

INTRODUCTION

Activity-related breathlessness is often the dominant symptom in patients with chronic obstructive pulmonary disease (COPD) and usually persists despite optimal medical therapy. Currently, our inability to meaningfully alter the pathophysiology of the underlying disease means that we must focus our attention on relieving this distressing symptom so as to improve exercise tolerance and quality of life.

AREAS COVERED

The current review examines the neurobiology of breathlessness and constructs a solid physiological rationale for amelioration of this distressing symptom. We will examine the efficacy of interventions which: 1) reduce the increased central drive to breathe (opioids); 2) improve the respiratory system's ability to appropriately respond to this increased demand (bronchodilators); and 3) address the important affective dimension of breathlessness (anxiolytics). Expert commentary: Advances in our understanding of the mechanisms of activity-related breathlessness in COPD, and its measurement in the clinical domain, now set the stage for the development of effective management strategies on an individual patient basis.

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.

A comparative ethnopharmacological analysis of traditional medicine used against respiratory tract diseases in Mauritius

ETHNOPHARMACOLOGICAL RELEVANCE

Despite laudable advances in conventional medicine, respiratory tract diseases (RTD) induced morbidity and mortality continue to inflict a substantial burden on healthcare systems worldwide. Similarly, in the tropical island of Mauritius, 13,320 hospital admissions and 8.2% mortality rates were attributed to RTD solely in the year 2013. Consequently, the therapeutic benefits and relief experienced with traditional medicine (TM) against RTD by the local inhabitants cannot be underestimated. The present study aims to report and quantitatively determine the extent of utilization of plant based therapies and other miscellaneous TM preparations concocted against RTD over the island. Additionally, a similarity index was generated which is indicative of the extent of harmonisation of individual plant species against RTD when the uses mentioned in the study are compared to previous ethnobotanical studies.

MATERIALS AND METHODS

Data was compiled using a semi-structured questionnaire via face-to-face interviews with TM users and practitioners (n=384). Three quantitative ethnopharmacological indices (the use value (UV), informant consensus factor (ICF), and ethnobotanicity index (EI)) were calculated. We also calculated the similarity ratio, similarity percentage, new uses for each plant species and percentage of new use against RTD to compare primary data collected in the present study.

RESULTS

Fifty five plants were documented to be in use against 18 RTD. The most used plant species belonged to the following taxa; Lamiaceae (9%), Fabaceae (7%) and Rutaceae (7%). Thirty two plants recorded in this study have been reported to be used against RTD in previous ethnobotanical studies, of which 22 of these plants have been attributed new uses against RTD based on the results of the present study. The remaining 23 plants species have been recorded for the first time to be used traditionally against RTD. Altogether, 81 different recipes were concocted from the medicinal plants and the most common route of administration was oral intake. Common methods of obtaining medicinal plants were from the wild, cultivation and as imported herbal products. Cough was the most common RTD managed by plant species. The largest proportion of plants were employed against cold. The preference ranking both for UV placed Curcuma longa L., Zingiber officinale Roscoe, Citrus×limonia Osbeck and Cymbopogon citratus (DC.) Stapf as the most useful plant species. Only a small proportion of the indigenous plants (7.73%) proved to be useful in TM.

CONCLUSION

This study provides empirical primary ethnopharmacological data on the use of TM to manage and/or treat RTD and can contribute in preserving indigenous knowledge in Mauritius. It is anticipated that these primary data will open new avenues to identify novel drugs that can help to alleviate sufferings.

Continuous Intravenous Morphine Infusion for Severe Dyspnea in Terminally Ill Interstitial Pneumonia Patients

OBJECTIVE

The aims of this study were to evaluate the efficacy and safety of continuous morphine infusion for dyspnea in patients with acute exacerbation (AE) of end-stage interstitial pneumonia (IP).

METHODS

We conducted a retrospective study. Based on the subjective clinical effectiveness ratings of "good," "moderate," "poor," or "unknown," the efficacy of continuous morphine infusion treatment was evaluated as defined as symptom relief that was "good" or "moderate."

PATIENTS

This study included 22 consecutive opioid-naïve patients who received continuous morphine infusion in the palliative treatment of dyspnea resulting from AE-IP.

RESULTS

Of 22 patients, nine achieved good dyspnea relief, eight had moderate relief, four had a poor response and one response was "unknown" within 24 hours of starting morphine infusion. Using an operational definition of dyspnea relief that was rated "good" or "moderate," the efficacy rate of morphine was 77% (n=17). There was a significant change in the respiratory rate (25 respirations per minute at baseline vs. 17 respirations per minute after 12 hours, p=0.02), however, none of the patients studied had fewer than eight respirations per minute.

CONCLUSION

We conclude that continuous morphine infusion is an effective and safe therapy for severe dyspnea in terminal AE-IP patients without any serious adverse events.

Incident opioid drug use among older adults with chronic obstructive pulmonary disease: a population-based cohort study

AIMS

The purpose of the present study was to describe the scope, pattern and patient characteristics associated with incident opioid use among older adults with chronic obstructive pulmonary disease (COPD).

METHODS

This was a retrospective population-based cohort study using Ontario, Canada, healthcare administrative data. Study participants were individuals aged 66 years and older with physician-diagnosed COPD, identified using a validated algorithm, who were not receiving palliative care. We examined the incidence of oral opioid receipt between 1 April 2003 and 31 March 2012, as well as several patterns of incident opioid drug use.

RESULTS

Among 107,109 community-dwelling and 16,207 long-term care resident older adults with COPD, 72,962 (68.1%) and 8811 (54.4%), respectively, received an incident opioid drug during the observation period. Among long-term care residents, multiple opioid dispensings (8.8%), dispensings for >30 days' duration (up to 19.8%), second dispensings (35-43%) and early refills (24.2%) were observed. Incident opioid dispensing was also observed to occur during COPD exacerbations (6.9% among all long-term care residents; 18.1% among long-term care residents with frequent exacerbations). These same patterns of incident opioid use occurred among community-dwelling individuals, but with relatively lower frequencies.

CONCLUSIONS

New opioid use was high among older adults with COPD. Potential safety concerns are raised by the degree and pattern of new opioid use, but further studies are needed to evaluate if adverse events are associated with opioid drug use in this older and respiratory-vulnerable population.

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.

Managing dyspnea in patients with advanced chronic obstructive pulmonary disease: a Canadian Thoracic Society clinical practice guideline

Dyspnea is a cardinal symptom of chronic obstructive pulmonary disease (COPD), and its severity and magnitude increases as the disease progresses, leading to significant disability and a negative effect on quality of life. Refractory dyspnea is a common and difficult symptom to treat in patients with advanced COPD. There are many questions concerning optimal management and, specifically, whether various therapies are effective in this setting. The present document was compiled to address these important clinical issues using an evidence-based systematic review process led by a representative interprofessional panel of experts. The evidence supports the benefits of oral opioids, neuromuscular electrical stimulation, chest wall vibration, walking aids and pursed-lip breathing in the management of dyspnea in the individual patient with advanced COPD. Oxygen is recommended for COPD patients with resting hypoxemia, but its use for the targeted management of dyspnea in this setting should be reserved for patients who receive symptomatic benefit. There is insufficient evidence to support the routine use of anxiolytic medications, nebulized opioids, acupuncture, acupressure, distractive auditory stimuli (music), relaxation, handheld fans, counselling programs or psychotherapy. There is also no evidence to support the use of supplemental oxygen to reduce dyspnea in nonhypoxemic patients with advanced COPD. Recognizing the current unfamiliarity with prescribing and dosing of opioid therapy in this setting, a potential approach for their use is illustrated. The role of opioid and other effective therapies in the comprehensive management of refractory dyspnea in patients with advanced COPD is discussed.

WITHDRAWN: Opioids for the palliation of breathlessness in advanced disease and terminal illness

BACKGROUND

Breathlessness is a common symptom in people with advanced disease. The most effective treatments are aimed at treating the underlying cause of the breathlessness but this may not be possible and symptomatic treatment is often necessary. Strategies for the symptomatic treatment of breathlessness have never been systematically evaluated. Opioids are commonly used to treat breathlessness: the mechanisms underlying their effectiveness are not completely clear and there have been few good-sized trials in this area.

OBJECTIVES

To determine the effectiveness of opioid drugs given by any route in relieving the symptom of breathlessness in patients who are being treated palliatively.

SEARCH METHODS

An electronic search was carried out of Medline, Embase, CINAHL, T he Cochrane L ibrary, Dissertation Abstracts, Cancercd and SIGLE. Review articles and reference lists of retrieved articles were hand searched. Date of most recent search: May 1999.

SELECTION CRITERIA

Randomised double-blind, controlled trials comparing the use of any opioid drug against placebo for the relief of breathlessness were included. Patients with any illness suffering from breathlessness were included and the intervention was any opioid, given by any route, in any dose.

DATA COLLECTION AND ANALYSIS

Studies identified by the search were imported into a reference manager database. The full texts of the relevant studies were retrieved and data were independently extracted by two review authors. Studies were quality scored according to the Oxford Quality scale. The primary outcome measure used was breathlessness and the secondary outcome measure was exercise tolerance. Studies were divided into non-nebulised and nebulised and were analysed both separately and together. A qualitative analysis was carried out of adverse effects of opioids. Where appropriate, meta-analysis was carried out.

MAIN RESULTS

Eighteen studies were identified of which nine involved the non-nebulised route of administration and nine the nebulised route. A small but statistically significant positive effect of opioids was seen on breathlessness in the analysis of studies using non-nebulised opioids. There was no statistically significant positive effect seen for exercise tolerance in either group of studies or for breathlessness in the studies using nebulised opioids.

AUTHORS' CONCLUSIONS

There is evidence to support the use of oral or parenteral opioids to palliate breathlessness although numbers of patients involved in the studies were small. No evidence was found to support the use of nebulised opioids. Further research with larger numbers of patients, using standardised protocols and with quality of life measures is needed.

Using laboratory models to test treatment: morphine reduces dyspnea and hypercapnic ventilatory response

RATIONALE

Opioids are commonly used to relieve dyspnea, but clinical data are mixed and practice varies widely.

OBJECTIVES

Evaluate the effect of morphine on dyspnea and ventilatory drive under well-controlled laboratory conditions.

METHODS

Six healthy volunteers received morphine (0.07 mg/kg) and placebo intravenously on separate days (randomized, blinded). We measured two responses to a CO(2) stimulus: (1) perceptual response (breathing discomfort; described by subjects as "air hunger") induced by increasing partial pressure of end-tidal carbon dioxide (Pet(CO2)) during restricted ventilation, measured with a visual analog scale (range, "neutral" to "intolerable"); and (2) ventilatory response, measured in separate trials during unrestricted breathing.

MEASUREMENTS AND MAIN RESULTS

We determined the Pet(CO2) that produced a 60% breathing discomfort rating in each subject before morphine (median, 8.5 mm Hg above resting Pet(CO2)). At the same Pet(CO2) after morphine administration, median breathing discomfort was reduced by 65% of its pretreatment value; P < 0.001. Ventilation fell 28% at the same Pet(CO2); P < 0.01. The effect of morphine on breathing discomfort was not significantly correlated with the effect on ventilatory response. Placebo had no effect.

CONCLUSIONS

(1) A moderate morphine dose produced substantial relief of laboratory dyspnea, with a smaller reduction of ventilation. (2) In contrast to an earlier laboratory model of breathing effort, this laboratory model of air hunger established a highly significant treatment effect consistent in magnitude with clinical studies of opioids. Laboratory studies require fewer subjects and enable physiological measurements that are difficult to make in a clinical setting. Within-subject comparison of the response to carefully controlled laboratory stimuli can be an efficient means to optimize treatments before clinical trials.

Benzodiazepines for the relief of breathlessness in advanced malignant and non-malignant diseases in adults

BACKGROUND

Breathlessness is one of the most common symptoms experienced in the advanced stages of malignant and non-malignant disease. Benzodiazepines are widely used for the relief of breathlessness in advanced diseases and are regularly recommended in the literature. However, the evidence for their use for this symptom is unclear.

OBJECTIVES

To determine the efficacy of benzodiazepines for the relief of breathlessness in patients with advanced disease.

SEARCH STRATEGY

We searched 14 electronic databases up to September 2009. We checked the reference lists of all relevant studies, key textbooks, reviews, and websites. We contacted investigators and specialists in palliative care for unpublished data.

SELECTION CRITERIA

We included randomised controlled trials (RCTs) and controlled clinical trials (CCTs) assessing the effect of benzodiazepines in relieving breathlessness in patients with advanced stages of cancer, chronic obstructive pulmonary disease (COPD), chronic heart failure (CHF), motor neurone disease (MND), and idiopathic pulmonary fibrosis (IPF).

DATA COLLECTION AND ANALYSIS

Two review authors independently assessed identified titles and abstracts. Three independent review authors performed assessment of all potentially relevant studies (full text), data extraction, and assessment of methodological quality. We carried out meta-analysis where appropriate.

MAIN RESULTS

Seven studies were identified, including 200 analysed participants with advanced cancer and COPD. Analysis of all seven studies (including a meta-analysis of six out of seven studies) did not show a beneficial effect of benzodiazepines for the relief of breathlessness in patients with advanced cancer and COPD. Furthermore, no significant effect could be observed in the prevention of breakthrough dyspnoea in cancer patients. Sensitivity analysis demonstrated no significant differences regarding type of benzodiazepine, dose, route and frequency of delivery, duration of treatment, or type of control.

AUTHORS' CONCLUSIONS

There is no evidence for a beneficial effect of benzodiazepines for the relief of breathlessness in patients with advanced cancer and COPD. There is a slight but non-significant trend towards a beneficial effect but the overall effect size is small. Benzodiazepines caused more drowsiness as an adverse effect compared to placebo, but less compared to morphine. These results justify considering benzodiazepines as a second or third-line treatment within an individual therapeutic trial, when opioids and non-pharmacological measures have failed to control breathlessness. Although a few good quality studies were included in this review, there is still a further need for well-conducted and adequately powered studies.

Caffeine for asthma

BACKGROUND

Caffeine has a variety of pharmacological effects; it is a weak bronchodilator and it also reduces respiratory muscle fatigue. It is chemically related to the drug theophylline which is used to treat asthma. It has been suggested that caffeine may reduce asthma symptoms and interest has been expressed in its potential role as an asthma treatment. A number of studies have explored the effects of caffeine in asthma, this is the first review to systematically examine and summarise the evidence.

OBJECTIVES

To assess the effects of caffeine on lung function and identify whether there is a need to control for caffeine consumption prior to either lung function or exhaled nitric oxide testing.

SEARCH STRATEGY

We searched the Cochrane Airways Group trials register and the reference lists of articles (August 2009). We also contacted study authors.

SELECTION CRITERIA

Randomised clinical trials of oral caffeine compared to placebo or coffee compared to decaffeinated coffee in adults with asthma.

DATA COLLECTION AND ANALYSIS

Trial selection, quality assessment and data extraction were done independently by two reviewers.

MAIN RESULTS

Seven trials involving a total of 75 people with mild to moderate asthma were included. The studies were all of cross-over design .Six trials involving 55 people showed that in comparison with placebo, caffeine, even at a 'low dose' (< 5mg/kg body weight), appears to improve lung function for up to two hours after consumption. Forced expiratory volume in one minute showed a small improvement up to two hours after caffeine ingestion (SMD 0.72; 95% CI 0.25 to 1.20), which translates into a 5% mean difference in FEV1. However in two studies the mean differences in FEV1 were 12% and 18% after caffeine. Mid-expiratory flow rates also showed a small improvement with caffeine and this was sustained up to four hours.One trial involving 20 people examined the effect of drinking coffee versus a decaffeinated variety on the exhaled nitric oxide levels in patients with asthma and concluded that there was no significant effect on this outcome.

AUTHORS' CONCLUSIONS

Caffeine appears to improve airways function modestly, for up to four hours, in people with asthma . People may need to avoid caffeine for at least four hours prior to lung function testing, as caffeine ingestion could cause misinterpretation of the results. Drinking caffeinated coffee before taking exhaled nitric oxide measurements does not appear to affect the results of the test, but more studies are needed to confirm this.

Hyperinflation and its management in COPD

Chronic obstructive pulmonary disease (COPD) is characterized by poorly reversible airflow limitation. The pathological hallmarks of COPD are inflammation of the peripheral airways and destruction of lung parenchyma or emphysema. The functional consequences of these abnormalities are expiratory airflow limitation and dynamic hyperinflation, which then increase the elastic load of the respiratory system and decrease the performance of the respiratory muscles. These pathophysiologic features contribute significantly to the development of dyspnea, exercise intolerance and ventilatory failure. Several treatments may palliate flow limitation, including interventions that modify the respiratory pattern (deeper, slower) such as pursed lip breathing, exercise training, oxygen, and some drugs. Other therapies are aimed at its amelioration, such as bronchodilators, lung volume reduction surgery or breathing mixtures of helium and oxygen. Finally some interventions, such as inspiratory pressure support, alleviate the threshold load associated to flow limitation. The degree of flow limitation can be assessed by certain spirometry indexes, such as vital capacity and inspiratory capacity, or by other more complexes indexes such as residual volume/total lung capacity or functional residual capacity/total lung capacity. Two of the best methods to measure flow limitation are to superimpose a flow–volume loop of a tidal breath within a maximum flow–volume curve, or to use negative expiratory pressure technique. Likely this method is more accurate and can be used during spontaneous breathing. A definitive definition of dynamic hyperinflation is lacking in the literature, but serial measurements of inspiratory capacity during exercise will document the trend of end-expiratory lung volume and allow establishing relationships with other measurements such as dyspnea, respiratory pattern, exercise tolerance, and gas exchange.

Global strategy for the diagnosis, management, and prevention of chronic obstructive pulmonary disease: GOLD executive summary

Chronic obstructive pulmonary disease (COPD) remains a major public health problem. It is the fourth leading cause of chronic morbidity and mortality in the United States, and is projected to rank fifth in 2020 in burden of disease worldwide, according to a study published by the World Bank/World Health Organization. Yet, COPD remains relatively unknown or ignored by the public as well as public health and government officials. In 1998, in an effort to bring more attention to COPD, its management, and its prevention, a committed group of scientists encouraged the U.S. National Heart, Lung, and Blood Institute and the World Health Organization to form the Global Initiative for Chronic Obstructive Lung Disease (GOLD). Among the important objectives of GOLD are to increase awareness of COPD and to help the millions of people who suffer from this disease and die prematurely of it or its complications. The first step in the GOLD program was to prepare a consensus report, Global Strategy for the Diagnosis, Management, and Prevention of COPD, published in 2001. The present, newly revised document follows the same format as the original consensus report, but has been updated to reflect the many publications on COPD that have appeared. GOLD national leaders, a network of international experts, have initiated investigations of the causes and prevalence of COPD in their countries, and developed innovative approaches for the dissemination and implementation of COPD management guidelines. We appreciate the enormous amount of work the GOLD national leaders have done on behalf of their patients with COPD. Despite the achievements in the 5 years since the GOLD report was originally published, considerable additional work is ahead of us if we are to control this major public health problem. The GOLD initiative will continue to bring COPD to the attention of governments, public health officials, health care workers, and the general public, but a concerted effort by all involved in health care will be necessary.