Low-dose nebulized morphine does not improve exercise in interstitial lung disease

IPF Respiratory Symptoms Management — Current Evidence

Idiopathic pulmonary fibrosis (IPF) is a progressive, chronic disease of the lungs which is characterized by heavy symptom burden, especially in the last year of life. Despite recently established anti-fibrotic treatment IPF prognosis is one of the worst among interstitial lung diseases. In this review available evidence regarding pharmacological and non-pharmacological management of the main IPF symptoms, dyspnea and cough, is presented.

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.

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.

Palliative care and interstitial lung disease

PURPOSE OF REVIEW

The palliative care needs of people with interstitial lung disease (ILD) have recently been highlighted by the National Institute for Health and Care Excellence. All people with progressive ILD should receive best supportive care to improve symptom control and quality of life and where possible this should be evidence based.

RECENT FINDINGS

Deaths from ILD are increasing and deaths in hospital are more common compared to home. People with ILD experience a wide range of symptoms including breathlessness and cough. People living with ILD often suffer unmet physical and psychological needs throughout the disease journey. Few appropriately validated outcome measures exist for ILD which has hampered research on the longitudinal experience of symptoms and quality of life and the evaluation of interventions. Recent recommendations from the National Institute of Clinical Excellence promote the use of a new palliative care needs assessment tool. Use of a tool in busy respiratory clinics may help to highlight those requiring specialist input.

SUMMARY

Further research into the role of opioids, oxygen and neuromodulatory agents in symptom management are needed. In addition, exploration of breathlessness and case conference interventions in transitioning patients from the hospital to community settings is a priority. Further work is needed to identify a core set of validated ILD-specific patient-reported outcome measures for the robust evaluation of interventions.

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.

Nebulized Morphine for Relief of Dyspnea Due to Chronic Lung Disease

OBJECTIVE:

To evaluate the efficacy and safety of nebulized morphine for the management of dyspnea in chronic pulmonary diseases.

DATA SOURCES:

MEDLINE (1966–May 2004), EMBASE (1980–May 2004), and International Pharmaceutical Abstracts (1970–May 2004) searches were performed. Key search terms included morphine, dyspnea, and inhalation.

DATA SYNTHESIS:

Nine studies have evaluated the efficacy of nebulized morphine in relieving dyspnea. Three trials had positive resuts, but the rest failed to show improvement after treatment with doses ranging from 1 to 40 mg nebulized morphine. The small number of subjects, variety of disease states, and different outcome measures limit interpretation of the studies.

CONCLUSIONS:

Results from several small studies do not support the use of nebulized morphine for treatment of dyspnea; however, several positive case reports have been published.

Chronic breathlessness in patients with idiopathic pulmonary fibrosis: a major challenge for caregivers

INTRODUCTION

Idiopathic pulmonary fibrosis (IPF) is one of the most common forms of interstitial lung disease, with a median survival time of two to five years. Most patients with IPF experience chronic breathlessness, which is closely linked to poor perceived quality of life and significant restriction of daily activities; therefore, effective management of this distressing symptom is a major goal of patient care. Areas covered: This report summarizes the physiology of IPF during rest and exercise, outlines current concepts of the mechanisms of breathlessness, and provides a physiological rationale for optimal management of individual patients. It also examines the evidence for efficacy of a number of therapeutic interventions currently at our disposal for the management of breathlessness in IPF, which aim to reduce respiratory neural drive, reduce worsening of mechanical load, and alter central perception. Expert commentary: The current evidence supporting general measures in relieving chronic breathlessness is weak; hence, more carefully designed prospective studies are required.

Patients with End-stage Interstitial Lung Disease may have More Problems with Dyspnea than End-stage Lung Cancer Patients

INTRODUCTION

Patients with end-stage interstitial  lung disease (ILD) do not appear to receive adequate palliative care despite apparent suffering before death. The aim of this study was to evaluate their signs, symptoms, and treatment received before death.

METHODS

Patients with ILD and lung cancer (LC) who were hospitalized and died in our hospital were enrolled retrospectively. Signs and symptoms and treatments at 7 days, 3 days, and 1 day before death were evaluated and compared between the two groups of patients.

RESULTS

A total of 23 patients with ILD and 59 patients with LC group were eligible for participation. Significantly more LC patients had loss of consciousness than ILD patients on 7 days (ILD: LC = 1 [5.6%]:24 [41%], P = 0.013), 3 days (1 [5.6%]:33 [56%], P < 0.001). Significantly more ILD patients had dyspnea than LC patients on 3 days (16 [89%]:38 [64%], P = 0.047) 1 day before death (21 [91%]:33 [56%], P = 0.001). On 1 day before death, significantly more LC patients received morphine than ILD patients (2 [8.7%]: 14 [24%], P = 0.015). More ILD patients received sedation (11 [48%]: 11 [19%], P = 0.007).

CONCLUSIONS

End-stage ILD patients may experience dyspnea more frequently than terminal LC patients, and they need sedation. Morphine should be administered to ILD patients who have dyspnea. Additional prospective studies are needed.

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.

Does nebulized fentanyl relieve dyspnea during exercise in healthy man?

Few therapies exist for the relief of dyspnea in restrictive lung disorders. Accumulating evidence suggests that nebulized opioids selective for the mu-receptor subtype may relieve dyspnea by modulating intrapulmonary opioid receptor activity. Our respective primary and secondary objectives were to test the hypothesis that nebulized fentanyl (a mu-opioid receptor agonist) relieves dyspnea during exercise in the presence of abnormal restrictive ventilatory constraints and to identify the physiological mechanisms of this improvement. In a randomized, double-blind, placebo-controlled crossover study, we examined the effect of 250 μg nebulized fentanyl, chest wall strapping (CWS), and their interaction on detailed physiological and perceptual responses to constant work rate cycle exercise (85% of maximum incremental work rate) in 14 healthy, fit young men. By design, CWS decreased vital capacity by ∼20% and mimicked the negative consequences of a mild restrictive lung disorder on exercise endurance time and on dyspnea, breathing pattern, dynamic operating lung volumes, and diaphragmatic electromyographic and respiratory muscle function during exercise. Compared with placebo under both unrestricted control and CWS conditions, nebulized fentanyl had no effect on exercise endurance time, integrated physiological response to exercise, sensory intensity, unpleasantness ratings of exertional dyspnea. Our results do not support a role for intrapulmonary opioids in the neuromodulation of exertional dyspnea in health nor do they provide a physiological rationale for the use of nebulized fentanyl in the management of dyspnea due to mild restrictive lung disorders, specifically those arising from abnormalities of the chest wall and not affiliated with airway inflammation.

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.

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.

Dyspnea in idiopathic pulmonary fibrosis: a systematic review

CONTEXT

Little is known about the treatment and correlates of dyspnea in idiopathic pulmonary fibrosis (IPF).

OBJECTIVES

The objective of this systematic review was to summarize the literature regarding the treatment and correlates of dyspnea in IPF.

METHODS

MEDLINE, EMBASE, and all Evidence-Based Medicine Reviews were searched for publications that evaluated treatment or correlates of dyspnea in IPF. Reference lists and recent review articles also were searched.

RESULTS

The heterogeneity of included studies did not permit meta-analysis. Dyspnea improved in studies of sildenafil, pulmonary rehabilitation, and prednisone with colchicine. Additional studies of these three treatments, however, found discordant results. One study suggested that assisted ventilation delivered by facemask improved exertional dyspnea. Oxygen and opioids improve dyspnea in other chronic lung diseases, but data in IPF are limited. Correlates of dyspnea included functional and physiological measures and comorbid diseases.

CONCLUSION

Sildenafil and pulmonary rehabilitation should be considered as potential therapies for dyspnea in selected patients with IPF. Supplemental oxygen and opioids may be additional potential therapies; however, the evidence supporting their use is weak. Additional research should focus on the management of functional status and comorbidities as potential treatments for dyspnea.

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

CONTEXT

Activity limitation and dyspnea are the dominant symptoms of chronic obstructive pulmonary disease (COPD). Traditionally, efforts to alleviate these symptoms have focused on improving ventilatory mechanics, reducing ventilatory demand, or both of these in combination. Nevertheless, many patients with COPD remain incapacitated by dyspnea and exercise intolerance despite optimal therapy.

OBJECTIVES

To determine the effect of single-dose inhalation of nebulized fentanyl citrate (a μ-opioid agonist drug) on exercise tolerance and dyspnea in COPD.

METHODS

In a randomized, double-blind, placebo-controlled, crossover study, 12 stable patients with COPD (mean ± standard error of the mean post-β(2)-agonist forced expiratory volume in one second [FEV(1)] and FEV(1) to forced vital capacity ratio of 69% ± 4% predicted and 49% ± 3%, respectively) received either nebulized fentanyl citrate (50 mcg) or placebo on two separate days. After each treatment, patients performed pulmonary function tests and a symptom-limited constant work rate cycle exercise test at 75% of their maximum incremental work rate.

RESULTS

There were no significant postdose differences in spirometric parameters or plethysmographic lung volumes. Neither the intensity nor the unpleasantness of perceived dyspnea was, on average, significantly different at isotime (5.0 ± 0.6 minutes) or at peak exercise after treatment with fentanyl citrate vs. placebo. Compared with placebo, fentanyl citrate was associated with 1) increased exercise endurance time by 1.30 ± 0.43 minutes or 25% ± 8% (P=0.01); 2) small but consistent increases in dynamic inspiratory capacity by ∼0.10 L at isotime and at peak exercise (both P≤0.03); and 3) no concomitant change in ventilatory demand, breathing pattern, pulmonary gas exchange, and/or cardiometabolic function during exercise. The mean rate of increase in dyspnea intensity (1.2 ± 0.3 vs. 2.9 ± 0.8 Borg units/minute, P=0.03) and unpleasantness ratings (0.5 ± 0.2 vs. 2.9 ± 1.3 Borg units/minute, P=0.06) between isotime and peak exercise was less after treatment with fentanyl citrate vs. placebo.

CONCLUSION

Single-dose inhalation of fentanyl citrate was associated with significant and potentially clinically important improvements in exercise tolerance in COPD. These improvements were accompanied by a delay in the onset of intolerable dyspnea during exercise near the limits of tolerance.

Effect of nebulized morphine on dyspnea of mustard gas-exposed patients: a double-blind randomized clinical trial study

Background. Dyspnea is one of the main complaints in a group of COPD patients due to exposure to sulfur mustard (SM) and is refractory to conventional therapies. We designed this study to evaluate effectiveness of nebulized morphine in such patients. Materials and Methods. In a double-blind clinical trial study, 40 patients with documented history of exposure to SM were allocated to two groups: group 1 who received 1 mg morphine sulfate diluted by 4 cc normal saline 0.5% using nebulizer once daily for 5 days and group 2 serving as control who received normal saline as placebo. They were visited by pulmonologist 7 times per day to check symptoms and signs and adverse events. Different parameters including patient-scored peak expiratory flow using pick flow meter, visual analogue scale (VAS) for dyspnea, global quality of life and cough, and number of respiratory rate, night time awaking for dyspnea and cough have been assessed. Results. The scores of VAS for dyspnea, cough and quality of life and also respiratory rate, heart rate, and night time awaking due to dyspnea and night time awaking due to cough improved significantly after morphine nebulization without any major adverse events. Also pick expiratory flow has been improved significantly after nebulization in each day. Conclusion. Our results showed the clinical benefit of nebulized morphine on respiratory complaints of patients due to exposure to SM without significant side effects.

Opioids for palliation of refractory dyspnea in chronic obstructive pulmonary disease patients

PURPOSE OF REVIEW

Dyspnea, a distressing symptom, in chronic obstructive pulmonary disease patients is often unrelieved. The purpose of this article is to examine the efficacy of opioids administered orally, in nebulized form and other routes in dyspnea relief. Additionally, factors that inhibit the prescription of opioids and use of opioids are explored.

RECENT FINDINGS

Although there are multiple case reports and case series, there is a paucity of well designed, prospective, randomized controlled trials with large enough number of chronic obstructive pulmonary disease patients. One review of randomized controlled trials and another randomized controlled trial found opioids effective in relieving dyspnea without causing major adverse effects.

SUMMARY

Opioid is an effective palliative drug in chronic obstructive pulmonary disease patients with distressing dypnea that is refractory to standard modalities of treatment.

Exercise limitation in interstitial lung disease - mechanisms, significance and therapeutic options

Exercise limitation is a cardinal feature of the interstitial lung diseases and is frequently associated with marked dyspnoea on exertion. People with interstitial lung disease exhibit a rapid, shallow breathing pattern during exercise that worsens as disease progresses. Despite this, ventilatory mechanics are not the major limitation to exercise in most patients, with impaired gas exchange and circulatory limitation playing a more important role. Peripheral and respiratory muscle dysfunction may also contribute to impaired exercise tolerance, either due to systemic manifestations of the underlying disease, treatment side-effects or deconditioning. Measures of exercise capacity or desaturation obtained from maximal and submaximal exercise tests are good predictors of survival in patients with idiopathic pulmonary fibrosis. However, to date few pharmaceutical treatments have affected exercise outcomes despite improvements in other important clinical markers. Supplemental oxygen acutely improves exercise capacity in interstitial lung disease and is recommended for hypoxic patients, although quality of life or survival benefits have not yet been demonstrated. Exercise training improves walking capacity and dyspnoea in short-term trials and is useful to maximize functional capacity. The role of exercise testing in the routine management of patients with interstitial lung disease is not clearly defined. However, given the poor prognosis in patients with idiopathic pulmonary fibrosis and the marked variation in clinical course, assessment of exercise capacity may provide useful information for both clinicians and patients when evaluating the risks and benefits of new treatments. The extent of resting or exercise-induced hypoxia in patients with interstitial lung disease may influence the selection of an appropriate exercise test, and oxygen administration should be standardized on repeat testing.

The Use of Nebulized Opioids in the Management of Dyspnea: Evidence Synthesis

PURPOSE/OBJECTIVES

To analyze the evidence about the use of nebulized opioids to treat dyspnea using the Priority Symptom Management (PRISM) level-of-evidence framework and to make a practice recommendation.

DATA SOURCES

Computerized database and manual search for articles and abstracts that included experimental trials, chart reviews, and case studies.

DATA SYNTHESIS

20 articles with evaluable evidence were identified. Analysis was complex because of heterogeneous variables and outcome measures. A major limitation is small sample sizes. The majority of PRISM level I and II studies indicated unfavorable evidence.

CONCLUSIONS

Scientific data supporting the use of nebulized opioids to treat dyspnea in patients with chronic pulmonary disease, including malignancy, are lacking.

IMPLICATIONS FOR NURSING

Insufficient data identify a need for further research with random crossover designs involving larger samples that are stratified according to prior opioid use. Consistency of study variables should be emphasized.

Palliative management of refractory dyspnea in COPD

COPD is a progressive illness with worldwide impact. Patients invariably reach a point at which they require palliative interventions. Dyspnea is the most distressing symptom experienced by these patients; when not relieved by traditional COPD management strategies it is termed "refractory dyspnea" and palliative approaches are required. The focus of care shifts from prolonging survival to reducing symptoms, increasing function, and improving quality of life. Numerous pharmacological and non-pharmacological interventions can achieve these goals, though evidence supporting their use is variable. This review provides a summary of the options for the management of refractory dyspnea in COPD, outlining currently available evidence and highlighting areas for further investigation. Topics include oxygen, opioids, psychotropic drugs, inhaled furosemide, Heliox, rehabilitation, nutrition, psychosocial support, breathing techniques, and breathlessness clinics.

Low dose diamorphine reduces breathlessness without causing a fall in oxygen saturation in elderly patients with end-stage idiopathic pulmonary fibrosis

There is very little evidence regarding the safety and efficacy of opioids for the control of dyspnoea in the terminal stages of idiopathic pulmonary fibrosis (IPF). We conducted an open case series study of 11 elderly opioid-naive patients referred for management of severe breathlessness before and after their first injection of 2.5 mg diamorphine subcutaneously. Subjective breathlessness, measured by a 100 mm visual analogue scale, fell by a mean of 47 mm in the first 15 min (P < 0.0001) and the mean heart rate fell by 12/min (P = 0.007). There were small non-significant falls in the mean respiratory rate (2/min), systolic blood pressure (6 mmHg) and oxygen saturation (1%). These changes were maintained at 30 min. Follow up treatment with oral morphine remained effective in reducing the symptom of breathlessness and no patient showed signs of respiratory depression. Low dose opioids are effective and safe in the palliative management of IPF in frail elderly patients.

Nebulized Opioids Use in COPD

OBJECTIVE

To evaluate the role of nebulized opioids in COPD.

METHODS

A MEDLINE search was completed to obtain pertinent clinical literature. Key search terms included the following: nebulizer, opioids, COPD, dyspnea, morphine, and hydromorphone.

RESULTS

Currently, the evidence in the literature is lacking regarding placebo-controlled studies to support nebulized morphine for the relief of dyspnea in patients with COPD. The studies reviewed varied considerably in the dose, opioid used, administration schedule, and methodology. One study found improved exercise capacity in 11 patients not reproducible in a larger sample, and another study found benefit in 54 terminal patients. All other studies found no benefit.

CONCLUSIONS

The recently published Global Initiative for Lung Disease guidelines have specifically stated that opioids are contraindicated in COPD management due to the potential respiratory depression and worsening hypercapnia. Nebulized opioids should be discouraged, as current data do not support their use.

A systematic review of the use of opioids in the management of dyspnoea

BACKGROUND

Opioids are commonly used to treat dyspnoea in palliative medicine but there has been no formal evaluation of the evidence for their effectiveness in the treatment of dyspnoea. A systematic review was therefore carried out to examine this.

METHODS

The criteria for inclusion required that studies were double blind, randomised, placebo controlled trials of opioids for the treatment of dyspnoea secondary to any cause. The methods used to identify suitable studies included electronic searching of the literature, hand searching of the literature, and personal contact with relevant individuals and organisations. Random effects meta-analyses were performed on all included studies and on various subgroups (studies involving nebulised opioids or patients with chronic obstructive pulmonary disease (COPD)). Subgroups were compared using meta-regression. Some studies included in the systematic review could not be included in the meta-analysis because insufficient data were presented.

RESULTS

Eighteen studies fulfilled the criteria for the review. The meta-analysis showed a statistically significant positive effect of opioids on the sensation of breathlessness (p=0.0008). Meta-regression indicated a greater effect for studies using oral or parenteral opioids than for studies using nebulised opioids (p=0.02). The subgroup analysis failed to show a positive effect of nebulised opioids on the sensation of breathlessness. The results of the subgroup analysis of the COPD studies were essentially similar to the results of the main analysis.

CONCLUSION

This review supports the continued use of oral and parenteral opioids to treat dyspnoea in patients with advanced disease. There are insufficient data from the meta-analysis to conclude whether nebulised opioids are effective, but the results from included studies that did not contribute to the meta-analysis suggest that they are no better than nebulised normal saline.

[Hormone expression and opioid receptors in fetal and adult lung]

OBJECTIVES

To describe the cellular distribution and level of expression of certain hormones and opioid receptors during fetal development and in the lung of the healthy adult.

METHOD

We sampled lung tissue from fetuses at three stages of development (pseudoglandular, canalicular and saccular) (3 samples per stage), from newborn infants (3), from 10-month-old infants (2) and from adults (3) who had died without lung disease. After specific immunohistochemical staining for hormones (calcitonin, parathormone, serotonin and adrenocorticotropic hormone - ACTH) and opioid receptors, we assessed the percentage of positive cells for each cell type in each sample.

RESULTS

Serotonin is the first to appear (pseudoglandular stage in isolated neuroendocrine cells) and it disappears later. Calcitonin appears in the canalicular stage in neuroendocrine and lung cells. Expression is at its peak at birth and is less in the adult lung. We found no ACTH or parathormone production. Opioid receptors appear in the canalicular stage and peak at birth. In adult lung, bronchiolar muscle and mesothelial cells, only delta-type opioid receptors are present.

CONCLUSIONS

Pulmonary hormone secretion is significant during fetal development and peaks at birth. Calcitonin is the main hormone produced in the fetal lung. Opioid receptors are present during fetal development in various types of cells and peak at birth. An understanding of the expression of active substances could have therapeutic relevance in certain conditions, such as bronchial asthma or respiratory distress syndrome in the child.

Palliative care of the chronically critically ill patient

Evidence is accumulating that distressing physical and emotional symptoms are prevalent among patients with critical illness, including those requiring prolonged mechanical ventilation, and that suffering is underestimated and undertreated by caregivers. Although patients and their families rank communication as a preeminent concern, it remains deficient in process and content, even when the illness requires weeks of critical care. Strategies are available to improve symptom management and communication about appropriate goals of care. For the CCI, whose risks of death, disability, and suffering are so high, it is essential that excellent palliative care be provided along with restorative treatment in an integrated way.

Managing dyspnea and cough

Dyspnea, like pain, is a subjective experience that incorporates physical elements and affective components. Management of breathlessness in patients with cancer requires expertise that includes an understanding and assessment of the multidimensional components of the symptom, knowledge of the pathophysiologic mechanisms and clinical syndromes that are common in cancer, and familiarity with the indications and limitations of the available therapeutic approaches. Relief of breathlessness should be the goal of treatment at all stages of cancer. Good control of dyspnea will improve the patient's quality of life.

Nebulized fentanyl citrate improves patients' perception of breathing, respiratory rate, and oxygen saturation in dyspnea

Dyspnea, a subjective symptom of impaired breathing, occurs in 70% of terminally ill cancer patients. Current treatments are suboptimal and little is known about the patient's perception of effect. We tested nebulized inhaled fentanyl citrate on patient perceptions, respiratory rate, and oxygen saturation. The study was conducted using a convenience sample of 35 cancer patients on a dedicated oncology unit. We assessed patient perception (did breathing stay the same, worsen, or improve), respiratory rate, and oxygen saturation by pulse oximetry at baseline, 5 minutes, and 60 minutes. Twenty-six of 32 (81%) patients reported improvement in breathing, 3 (9%) were unsure, and 3 (9%) reported no improvement. Oxygen saturation improved from 94.6% at baseline to 96.8% at 5 minutes and 96.7% at 60 minutes (P = 0.0069 compared to baseline). Respiratory rates improved from a baseline of 28.4/min to 25.9/min at 5 minutes and 24.1/min at 60 minutes (P = 0.0251 compared to baseline). No side effects were observed. Inhaled nebulized fentanyl citrate significantly improved patient perception of breathing, respiratory rate, and oxygen saturation. This inexpensive and readily available treatment may offer substantial relief of end-of-life dyspnea. Randomized trials, dose, and length of effect trials are underway.

Nebulised morphine for severe interstitial lung disease

BACKGROUND

The evidence to support the use of nebulized morphine to improve dyspnoea and exercise limitation in terminally ill patients with chronic lung disease is conflicting.

OBJECTIVES

To assess the effectiveness of nebulized morphine in reducing dyspnoea in patients with end-stage interstitial lung disease

SEARCH STRATEGY

RCTs and good quality CCTs were identified by searching Medline, Embase, Cinahl as well as the Cochrane controlled clinical trial register. The following search terms were used: (inhaled OR nebulised)/AND/morphine AND/Idiopathic pulmonary fibrosis/or/pulmonary fibrosis/or/idiopathic interstitial pneumonia/or/nonspecific interstitial pneumonia/or/non-specific interstitial pneumonia/or/usual interstitial pneumonia/or/desquamative interstitial pneumonia/or/cryptogenic fibrosing alveolitis/or/interstitial pneumonia/or/idiopathic interstitial lung disease/or/chronic interstitial pneumonia

SELECTION CRITERIA

Any RCT and adequate quality CCT in adult patients with ILD that compared nebulized morphine with a control group.

DATA COLLECTION AND ANALYSIS

Only one small RCT was identified.

MAIN RESULTS

Compared to placebo (normal saline), administration of low-dose nebulized morphine (2.5 and 5.0 mg) to six patients with ILD did not improve maximal exercise performance, and did not reduce dyspnoea during exercise.

REVIEWER'S CONCLUSIONS

The hypothesis that nebulized morphine may reduce dyspnoea in patients with interstitial lung disease has not been confirmed in the single small RCT identified.

Opioids for the palliation of breathlessness in 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 STRATEGY

An electronic search was carried out of Medline, Embase, Cinahl, the Cochrane library, 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 reviewers. Studies were quality scored according to the Jadad 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.

REVIEWER'S 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.

Lung opioid receptors: pharmacology and possible target for nebulized morphine in dyspnea

Opioid receptors are located throughout the respiratory tract. Yet, these have received relatively scant attention compared to other opioid receptors. The most abundant sites within the respiratory tract appear localized within the alveolar walls, other sites appear to line the smooth muscle within the trachea and main bronchi near the lumen. There is about 100-times greater [3H]morphine binding density within the bronchioles and lobes than in the main bronchi or trachea. In addition to the usual mu, delta and kappa types of opioid receptors, 'non-conventional' opioid binding sites have been suggested, although the function of these or of the other opioid receptors in the pulmonary tract is not known. However, they might explain the otherwise counterintuitive apparent utility of morphine treatment of dyspnea. Dyspnea is a common and distressing symptom in terminally-ill cancer patients and patients with chronic lung disease. It results from multiple causes, is difficult to treat and is a significant precipitating factor for late-stage hospital or hospice admissions. Nebulized morphine or other opioids have been reported to have beneficial effect, but the mechanism by which opioids might produce this seemingly contradictory effect is not clear. We review here lung opioid receptor distribution, pharmacology and possible clinical relevance in the treatment of dyspnea.

Management of dyspnea in severe chronic obstructive pulmonary disease

Progression of chronic obstructive pulmonary disease (COPD) is frequently associated with increasing dyspnea; indeed, patients with severe COPD constitute the largest group of patients with chronic respiratory insufficiency. The sensation of dyspnea in these patients is mostly related to increased work of breathing, a consequence of an increased resistive load, of hyperinflation, and of the deleterious effect of intrinsic positive end-expiratory pressure (PEEP(i)). Once optimal medical treatment has been provided, pharmacological treatments of dyspnea exist (beta2-agonists, methylxanthines, opiates) but seldom suffice. Nonpharmacological complementary treatments must be envisioned. Patients with severe hyperinflation should be screened as possible candidates for lung reduction surgery. Pulmonary rehabilitation-including chest therapy, patient education, exercise training-has been established as effective on quality of life (QoL) and dyspnea. Noninvasive positive pressure devices may be effective for symptomatic treatment of severe dyspnea: continuous positive airway pressure (CPAP) counteracts the deleterious effect of PEEP(i) in patients with severe hyperinflation; intermittent positive pressure breathing (IPPB) may decrease dyspnea and discomfort during nebulized therapy; finally noninvasive positive pressure ventilation (NIPPV) has been shown to be effective on the sensation of dyspnea and QoL in COPD with severe hypercapnia.

Nebulized opioids to treat dyspnea

Breathlessness secondary to cancer and nonmalignant disease is very distressing and exhausting to patients and families. Patient quality of life and functionality can be greatly improved with effective management. The pathophysiology and treatment of dyspnea are where the science of pain management was 20 years ago. While the optimal therapy for dyspnea would be to treat the underlying cause, this is frequently not possible. Research results evaluating dosages and effectiveness of nebulized morphine are conflicting. Some researchers have reported dramatic benefit to patients in relieving the symptoms of dyspnea, increasing exercise endurance, and improving function. Other studies have reported no significant differences between nebulized morphine and saline with or without oxygen. Studies that administer single predetermined doses that are not titrated to relief in patients that do not have end-stage lung or cardiac disease may report false-negative results. Other factors such as the placebo effect of saline and oxygen, if not controlled, may cause false-positive results. The dramatic positive benefits documented warrant further investigation on the appropriate patient selection criteria and therapeutic potential. Clearly, large scale randomized trials on opioid nebulized treatments for patients with severe dyspnea need to be published to reach a clear consensus outlining efficacy and administration parameters. Until that time, we must rely on anecdotal reports for treatment options. Such reports of the effectiveness of nebulized morphine as an alternative to hospital or hospice admission are encouraging for patients and family members managing severe dyspnea in the home.

Nebulized Morphine for the Treatment of Dyspnea in Cancer Patients

Objective:

To review the literature concerning the use of nebulized opioids to treat dyspnea in terminally ill cancer patients.

Data Sources:

English-language journal articles were obtained by a MEDLINE search (1966-August 1997).

Study Selection:

All clinical trials and case reports involving nebulized opioids. Representative studies discussing neurogenic inflammation and pulmonary opioid receptors were also reviewed.

Data Extraction:

Studies were selected for review on the basis of study design and use of nebulized opioids. Case reports were selected from the palliative care literature.

Data Synthesis:

High-density, low-affinity opioid receptors have been identified in lung tissue and may play a role in the alleviation of dyspnea in some patients. The activation of these receptors in the lung may attenuate the release of inflammatory mediators and neuropeptides such as substance P. However, because nebulized opioids are absorbed buccally or through the airway mucosa, the relief observed may be due to a central rather than peripheral effect.

Conclusions:

Several case reports in the palliative care literature have described favorable results when nebulized opioids are used to treat dyspnea. However, data from controlled trials in populations other than patients with cancer do not substantiate the use of nebulized opioids. Unfortunately, controlled clinical trials have not been conducted in cancer patients; thus, extrapolation is difficult. Well-designed clinical trials in patients with cancer are necessary to determine the efficacy of nebulized morphine in treating dyspnea.

Acute respiratory depression as a complication of nebulised morphine

PURPOSE

To present a case of respiratory depression following the administration of nebulised morphine.

CLINICAL FEATURES

A 74-yr-old, 51-kg woman with a history of hypertension controlled with 5 mg.day-1 enalapril and 50 mg.day-1 atenolol was admitted for evaluation of low back pain, loss of appetite, and weight loss. Investigation revealed advanced metastatic disease with a probable primary in the right lung. The patient's pain was well controlled with 10 mg continuous release morphine p.o. three times daily, and 10 mg immediate release morphine p.o. for breakthrough pain as required. During the two weeks following the commencement of this treatment she occasionally complained of shortness of breath. Examination revealed a fully conscious patient with slight dyspnoea and mild wheezing which responded to oxygen 30% and nebulised bronchodilators. An oncological consultation recommended 4 mg nebulised morphine and 4 mg dexamethasone in saline as treatment for the bouts of breathlessness. Approximately 15 min after the first administration of nebulised morphine the patient became markedly bradypneic (respiratory rate: 4-5 bpm), hypotensive (BP 70/40 mmHg), and responded only partially to command. The pupils were pinpoint. The trachea was immediately intubated and the lungs ventilated with oxygen 40% for four hours. Following this occurrence of respiratory depression nebulised morphine was discontinued and no further events occurred.

CONCLUSION

Patients receiving inhaled morphine should be closely monitored and resuscitation equipment should be readily available.