Effect of aerosolized recombinant human DNase on exacerbations of respiratory symptoms and on pulmonary function in patients with cystic fibrosis. The Pulmozyme Study Group

BACKGROUND

Respiratory disease in patients with cystic fibrosis is characterized by airway obstruction caused by the accumulation of thick, purulent secretions, which results in recurrent, symptomatic exacerbations. The viscoelasticity of the secretions can be reduced in vitro by recombinant human deoxyribonuclease I (rhDNase), a bioengineered copy of the human enzyme.

METHODS

We performed a randomized, double-blind, placebo-controlled study to determine the effects of once-daily and twice-daily administration of rhDNase on exacerbations of respiratory symptoms requiring parenteral antibiotics and on pulmonary function. A total of 968 adults and children with cystic fibrosis were treated for 24 weeks as outpatients.

RESULTS

One or more exacerbations occurred in 27 percent of the patients given placebo, 22 percent of those treated with rhDNase once daily, and 19 percent of those treated with rhDNase twice daily. As compared with placebo, the administration of rhDNase once daily and twice daily reduced the age-adjusted risk of respiratory exacerbations by 28 percent (P = 0.04) and 37 percent (P < 0.01), respectively. The administration of rhDNase once daily and twice daily improved forced expiratory volume in one second during the study by a mean (+/- SD) of 5.8 +/- 0.7 and 5.6 +/- 0.7 percent, respectively. None of the patients had anaphylaxis. Voice alteration and laryngitis were more frequent in the rhDNase-treated patients than in those receiving placebo but were rarely severe and resolved within 21 days of onset.

CONCLUSIONS

In patients with cystic fibrosis, the administration of rhDNase reduced but did not eliminate exacerbations of respiratory symptoms, resulted in slight improvement in pulmonary function, and was well tolerated.

Chronic bronchitis and chronic obstructive pulmonary disease

Chronic bronchitis (CB) is a common but variable phenomenon in chronic obstructive pulmonary disease (COPD). It has numerous clinical consequences, including an accelerated decline in lung function, greater risk of the development of airflow obstruction in smokers, a predisposition to lower respiratory tract infection, higher exacerbation frequency, and worse overall mortality. CB is caused by overproduction and hypersecretion of mucus by goblet cells, which leads to worsening airflow obstruction by luminal obstruction of small airways, epithelial remodeling, and alteration of airway surface tension predisposing to collapse. Despite its clinical sequelae, little is known about the pathophysiology of CB and goblet cell hyperplasia in COPD, and treatment options are limited. In addition, it is becoming increasingly apparent that in the classic COPD spectrum, with emphysema on one end and CB on the other, most patients lie somewhere in the middle. It is known now that many patients with severe emphysema can develop CB, and small airway pathology has been linked to worse clinical outcomes, such as increased mortality and lesser improvement in lung function after lung volume reduction surgery. However, in recent years, a greater understanding of the importance of CB as a phenotype to identify patients with a beneficial response to therapy has been described. Herein we review the epidemiology of CB, the evidence behind its clinical consequences, the current understanding of the pathophysiology of goblet cell hyperplasia in COPD, and current therapies for CB.

Treatment of idiopathic bronchiectasis with aerosolized recombinant human DNase I. rhDNase Study Group

STUDY OBJECTIVE

To study the safety and efficacy of aerosolized recombinant human DNase I in the treatment of idiopathic bronchiectasis.

DESIGN

Double-blind, randomized, placebo-controlled, multicenter study.

POPULATIONS

Three hundred forty-nine adult outpatients in stable condition with idiopathic bronchiectasis from 23 centers in North America, Great Britain, and Ireland.

INTERVENTIONS AND MEASUREMENTS

Study patients received aerosolized rhDNase or placebo twice daily for 24 weeks. Primary end points were incidence of pulmonary exacerbations and mean percent change in FEV1 from baseline over the treatment period.

RESULTS

Pulmonary exacerbations were more frequent and FEV1 decline was greater in patients who received rhDNase compared with placebo during this 24-week trial.

CONCLUSIONS

rhDNase was ineffective and potentially harmful in this group of adult outpatients in stable condition with idiopathic bronchiectasis. This contrasts with previously published results that demonstrated efficacy of rhDNase in patients with cystic fibrosis bronchiectasis.

Effect of carbocisteine on acute exacerbation of chronic obstructive pulmonary disease (PEACE Study): a randomised placebo-controlled study

BACKGROUND

Chronic obstructive pulmonary disease (COPD) is characterised by airflow limitation, and has many components including mucus hypersecretion, oxidative stress, and airway inflammation. We aimed to assess whether carbocisteine, a mucolytic agent with anti-inflammatory and antioxidation activities, could reduce the yearly exacerbation rate in patients with COPD.

METHODS

We did a randomised, double-blind, placebo-controlled study of 709 patients from 22 centres in China. Participants were eligible if they were diagnosed as having COPD with a postbronchodilator forced expiratory volume in 1 s (FEV(1)) to forced vital capacity (FVC) ratio (FEV(1)/FVC) of less than 0.7 and an FEV(1) between 25% and 79% of the predicted value, were aged between 40 and 80 years, had a history of at least two COPD exacerbations within the previous 2 years, and had remained clinically stable for over 4 weeks before the study. Patients were randomly assigned to receive 1500 mg carbocisteine or placebo per day for a year. The primary endpoint was exacerbation rate over 1 year, and analysis was by intention to treat. This trial is registered with the Japan Clinical Trials Registry (http://umin.ac.jp/ctr/index/htm) number UMIN-CRT C000000233.

FINDINGS

354 patients were assigned to the carbocisteine group and 355 to the placebo group. Numbers of exacerbations per patient per year declined significantly in the carbocisteine group compared with the placebo group (1.01 [SE 0.06] vs 1.35 [SE 0.06]), risk ratio 0.75 (95% CI 0.62-0.92, p=0.004). Non-significant interactions were found between the preventive effects and COPD severity, smoking, as well as concomitant use of inhaled corticosteroids. Carbocisteine was well tolerated.

INTERPRETATION

Mucolytics, such as carbocisteine, should be recognised as a worthwhile treatment for prevention of exacerbations in Chinese patients with COPD.

A two-year randomized, placebo-controlled trial of dornase alfa in young patients with cystic fibrosis with mild lung function abnormalities

OBJECTIVE

Our objective was to determine whether long-term treatment of young patients with cystic fibrosis (CF) with dornase alfa maintains lung function and reduces respiratory tract exacerbations.

STUDY DESIGN

This was a 96-week, randomized, double-blind, placebo-controlled trial involving 49 CF centers. Inclusion criteria were age 6 to 10 years and forced vital capacity > or = 85% predicted. Patients were excluded for hospitalization for complications of CF within 2 months and use of dornase alfa within 6 months. Patients were treated with dornase alfa 2.5 mg or placebo once daily with a jet nebulizer and a compressor.

RESULTS

Patients were randomized, 239 to dornase alfa and 235 to placebo. At baseline the mean age was 8.4 years, the mean forced expiratory volume in 1 second 95% predicted, the mean forced expiratory flow, midexpiratory phase 85% predicted, and the mean forced vital capacity 102% predicted. At 96 weeks the treatment benefit for dornase alfa compared with placebo in percent predicted (mean +/- SE) was 3.2 +/- 1.2 for forced expiratory volume in 1 second (P =.006), 7.9 +/- 2.3 for forced expiratory flow between 25% and 75% of vital capacity (P =.0008), and 0.7 +/- 1.0 for forced vital capacity (P =.51). The risk of respiratory tract exacerbation was reduced by 34% in patients who received dornase alfa (relative risk 0.66, P =.048). There was no statistically significant difference between the groups in changes in weight-for-age percentile. Adverse event profiles for the treatment groups were similar.

CONCLUSIONS

Treatment of young patients with CF with dornase alfa maintains lung function and reduces the risk of exacerbations over a 96-week period.

Characterization of N-acetylcysteine and ambroxol in anti-oxidant therapy

Reactive free oxygen radicals are known to play an important role in the pathogenesis of various lung diseases such as idiopathic pulmonary fibrosis (IPF), adult respiratory distress syndrome (ARDS) or cystic fibrosis (CF). They can originate from endogenous processes or can be part of exogenous exposures (e.g. ozone, cigarette smoke, asbestos fibres). Consequently, therapeutic enhancement of anti-oxidant defence mechanisms in these lung disorders seems a rational approach. In this regard, N-acetyl-L-cysteine (NAC) and ambroxol have both been frequently investigated. Because of its SH group, NAC scavenges H2O2 (hydrogen peroxide), .OH (hydroxol radical), and HOCl (hypochlorous acid). Furthermore, NAC can easily be deacetylated to cysteine, an important precursor of cellular glutathione synthesis, and thus stimulate the cellular glutathione system. This is most evident in pulmonary diseases characterized by low glutathione levels and high oxidant production by inflammatory cells (e.g. in IPF and ARDS). NAC is an effective drug in the treatment of paracetamol intoxication and may even be protective against side-effects of mutagenic agents. In addition NAC reduces cellular production of pro-inflammatory mediators (e.g. TNF-alpha, IL-1). Also, ambroxol [trans-4-(2-amino-3,5-dibromobenzylamino)-cyclohexane hydrochloride] scavenges oxidants (e.g. .OH, HOCl). Moreover, ambroxol reduces bronchial hyperreactivity, and it is known to stimulate cellular surfactant production. In addition, ambroxol has anti-inflammatory properties owing to its inhibitory effect on the production of cellular cytokines and arachidonic acid metabolites. For both substances effective anti-oxidant and anti-inflammatory function has been validated when used in micromolar concentrations. These levels are attainable in vivo in humans. This paper gives an up-to-date overview about the current knowledge of the hypothesis that oxidant-induced cellular damage underlies the pathogenesis of many human pulmonary diseases, and it discusses the feasibility of anti-oxidant augmentation therapy to the lung by using NAC or ambroxol.

Real-time multiple-particle tracking: applications to drug and gene delivery

Complex biological environments, such as the cell cytoplasm or the mucus lining the airways of the lungs, can pose significant barriers to efficient therapeutic drug and gene delivery. Biological barriers are particularly important in controlled drug delivery applications that utilize a large carrier particle, such as a liposome or a polymer micro- or nanosphere. The dynamic transport of particulate drug and gene delivery vehicles through these barriers is poorly understood, having been primarily studied with static methods in the past. Recently, the transport of synthetic drug and gene carriers has been investigated quantitatively with real-time particle tracking technology, providing new insight into particle behavior in complex biological environments that is guiding rational improvements in particle design. This review briefly highlights basic principles of particle tracking and its application to elucidate important phenomena that limit effective particulate drug and gene delivery.

The effect of oral N-acetylcysteine in chronic bronchitis: a quantitative systematic review

The role of N-acetylcysteine (NAC) in the treatment of chronic bronchitis is unclear. Since a number of studies have been published on this topic, a systematic review of published studies seems justified. A systematic search (Medline, Embase, Cochrane Library, bibliographies, no language restriction) for published randomized trials comparing oral NAC with placebo in patients with chronic bronchitis was performed. Dichotomous data on prevention of exacerbation, improvement of symptoms and adverse effects were extracted from original reports. The relative benefit and number-needed-to-treat were calculated for both individual trials and combined data. Thirty-nine trials were retrieved; eleven (2,011 analysed patients), published 1976-1994, were regarded as relevant and valid according to preset criteria. In nine studies, 351 of 723 (48.5%) patients receiving NAC had no exacerbation compared with 229 of 733 (31.2%) patients receiving placebo (relative benefit 1.56 (95% confidence interval (CI) 1.37-1.77), number-needed-to-treat 5.8 (95% CI 4.5-8.1). There was no evidence of any effect of study period (12-24 weeks) or cumulative dose of NAC on efficacy. In five trials, 286 of 466 (61.4%) patients receiving NAC reported improvement of their symptoms compared with 160 of 462 (34.6%) patients receiving placebo (relative benefit 1.78 (95% CI 1.54-2.05), number-needed-to-treat 3.7 (95% CI 3.0-4.9)). With NAC, 68 of 666 (10.2%) patients reported gastrointestinal adverse effects compared with 73 of 671 (10.9%) taking placebo. With NAC, 79 of 1,207 (6.5%) patients withdrew from the study due to adverse effects, compared with 87 of 1,234 (7.1%) receiving placebo. In conclusion, with treatment periods of approximately 12-24 weeks, oral N-acetylcysteine reduces the risk of exacerbations and improves symptoms in patients with chronic bronchitis compared with placebo, without increasing the risk of adverse effects. Whether this benefit is sufficient to justify the routine and long-term use of N-acetylcysteine in all patients with chronic bronchitis should be addressed in further studies and cost-effectiveness analyses.

Effect of hypertonic saline, amiloride, and cough on mucociliary clearance in patients with cystic fibrosis

In patients with cystic fibrosis (CF), dehydration of airway secretions leads to a decrease in mucociliary clearance (MCC). We examined the acute effect of MCC of a single administration by aerosolization of hypertonic saline (7%) (HS), amiloride (0.3% in 0.12% NaCl) (AML) and a combination of AML and HS (AML + HS) in 12 patients with CF using a radioaerosol technique. Isotonic saline [0.9%] (IS) was used as a control solution. As both the AML and HS solutions induced cough in some patients, the last nine patients studied also underwent a cough clearance day. This was to eliminate the possible confounding effect of cough on MCC measurement. Patients ranged from 18 to 28 yr (mean +/- SD, 22 +/- 3) with an FEV1 of 27 to 112% predicted (61 +/- 30%). Following deposition of the radioaerosol, baseline clearance was assessed for 30 min. This was followed by a 30-min intervention period. Assessment of post-intervention clearance for a further 30 min was then performed. Comparison of the amount of radioaerosol cleared from the right lung was made at 60 min (%C60) and 90 min (%C90) using repeated measures ANOVA. The percent cleared at 60 and 90 min was significantly increased with HS (%C60 = 26.5%, %C90 = 29.4%) and the combination of AML + HS (%C60 = 23.1%, %C90 = 27.4%) compared with both IS (%C60 = 14.7%, %C90 = 17.5%) and COUGH (%C60 = 18.0%, %C90 = 19.5%), p < 0.01. Inhalation of hypertonic saline is a potentially useful treatment in patients with cystic fibrosis.

Management of acute exacerbations of chronic obstructive pulmonary disease: a summary and appraisal of published evidence

PURPOSE

To review critically the available data on diagnostic evaluation, risk stratification, and therapeutic management of patients with acute exacerbations of chronic obstructive pulmonary disease (COPD).

DATA SOURCES

English-language articles were identified by searching MEDLINE (1966 to 2000, week 5), EMBASE (1974 to 2000, week 18), HealthStar (1975 to June 2000), and the Cochrane Controlled Trials Register (2000, Issue 1).

STUDY SELECTION

The best available evidence on each subtopic was selected for analysis. Randomized trials, sometimes buttressed by cohort studies, were used to evaluate therapeutic interventions. Cohort studies were used to evaluate diagnostic tests and risk stratification.

DATA EXTRACTION

Study design and results were summarized in evidence tables. Individual studies were rated by internal validity, external validity, and quality of design. Statistical analyses of combined data were not performed.

DATA SYNTHESIS

Data on the utility of most diagnostic tests are limited. However, chest radiography and arterial blood gas sampling seem useful while acute spirometry does not. Identifiable clinical variables are associated with risk for relapse and risk for death after hospitalization for an acute exacerbation. Evidence of efficacy was found for bronchodilators, corticosteroids, and noninvasive positive-pressure ventilation. There is also support for the use of antibiotics in patients with more severe exacerbations. On the basis of limited data, mucolytics and chest physiotherapy do not seem to be of benefit, and oxygen supplementation seems to increase the risk for respiratory failure only in an identifiable subgroup of patients.

CONCLUSIONS

Although suggestions for appropriate management can be made on the basis of available evidence, the supporting literature is scarce and further high-quality research is necessary. Such research will require an improved, generally acceptable, and transportable definition of acute exacerbation of COPD, as well as improved methods for observing and measuring outcomes.

Effectiveness of amitriptyline versus cough suppressants in the treatment of chronic cough resulting from postviral vagal neuropathy

OBJECTIVE

The objective of this prospective, randomized, controlled study (N = 28) was to evaluate the effectiveness of amitriptyline versus cough suppressants in the treatment of chronic cough resulting from postviral vagal neuropathy.

METHODS

Patients were selected based on a clinical history consistent with postviral vagal neuropathy and a history of an antecedent upper respiratory tract infection. All patients had been tried on antireflux medication (proton pump inhibitors) and had a negative chest x-ray before presentation. All were nonsmokers without a history of asthma. Patients on angiotensin-converting enzyme inhibitors were excluded from the study. All patients completed a pretreatment, validated cough-specific quality-of-life (QOL) survey. Patients were randomized by chart numbers to either 10 mg amitriptyline at bedtime or 10 to 100 mg/5 mL, 10 mL codeine/guaifenesin every 6 hours standing dose while awake. Both groups were instructed to complete 10 days of therapy and then asked to subjectively rate the reduction in the frequency and severity of their cough by 100%, 75%, 50%, 25%, or 0% as well as completing the posttreatment cough QOL questionnaire. Those patients experiencing a 75% to 100% reduction were recorded as having a complete response, 25% to 50% a partial response, and 0% as having no response. Final results and the cough QOL survey were recorded and used for statistical analysis.

RESULTS

A majority of patients in the amitriptyline group achieved a complete response on the initial dose of 10 mg. None of the codeine/guaifenesin group achieved a complete response. The data were analyzed using a logistic regression model, and amitriptyline was found to be a highly significant predictor of a greater than 50% response when compared with codeine/guaifenesin (P = .0007). The same data were analyzed using a proportional odds model and similar results were noted.

CONCLUSIONS

Chronic cough can have a profound impact on the psychosocial function of patients. The most common causes of a persisting cough in the absence of infection or chronic smoking are laryngopharyngeal reflux, asthma, particularly the cough variant, allergy, rhinosinusitis, bronchitis, and medications, in particular angiotensin-converting enzyme inhibitors. Currently, there are few effective treatments for cough with an acceptable therapeutic ratio and more selective drugs with a more favorable side effect profile are needed. This is this first prospective, randomized, controlled study comparing the effectiveness of amitriptyline versus codeine/guaifenesin for select cases of chronic cough resulting from suspected postviral vagal neuropathy.

"Feed a cold, starve a fever"--folk models of infection in an English suburban community, and their relation to medical treatment

This paper outlines a widely-held conception of illness, related to perceived changes in body temperature--'Chills' and 'Colds' on one hand, 'Fevers' on the other---in an English suburban community on the outskirts of London. The relationship between this folk model, and that of the local family physicians is analysed, to show how biomedical treatment and concepts, particularly the germ theory of disease, far from challenging the folk model, actually reinforce it. Remedies which cannot be scientifically and biomedically justified are nevertheless prescribed by the physicians to meet their patients' need to 'make sense' of biomedical treatment in terms of their folk model of illness. At the interface between physicians and patient, biomedical diagnoses and treatment are more 'negotiable' than previously realised--and this has important implications for the delivery of health care.

Pseudomyxoma peritonei

BACKGROUND

Pseudomyxoma peritonei is an unusual condition in which gelatinous fluid collections are associated with mucinous implants on the peritoneal surfaces and omentum. The pathological origin and ideal treatment of the condition are subjects of debate.

METHODS

An unrestricted Medline search over 1986-1997 was performed for pseudomyxoma peritonei.

RESULTS AND CONCLUSIONS

There is increasing evidence that pseudomyxoma peritonei is a neoplastic condition which usually arises from a primary adenoma or adenocarcinoma of the appendix. Reported series include a spectrum of pathological lesions, from entirely benign ruptured mucocele to advanced carcinoma. This, and the rarity of the condition, limit the conclusions that can be drawn regarding its treatment and prognosis. Most authorities agree that a thorough surgical debulking should be made. In most cases this will be a difficult and time-consuming undertaking, possibly requiring cooperation between two or more specialists and consideration of delivering intraperitoneal adjuvant therapy during or immediately after surgery. Treatment therefore requires a planned approach with accurate preoperative assessment of the diagnosis and the extent of the condition. There is some largely anecdotal evidence in favour of intraperitoneal chemotherapy and radioisotope treatment. Ultraradical surgery, with heated intraoperative and further postoperative chemotherapy, is strongly advocated by one group but remains contentious. The majority of patients will eventually suffer recurrence. The 5-year survival rate ranges from 53 to 75 per cent, but outcomes vary widely between relatively benign and malignant subgroups.

Oral mucolytic drugs for exacerbations of chronic obstructive pulmonary disease: systematic review

OBJECTIVE

To assess the effects of oral mucolytics in adults with stable chronic bronchitis and chronic obstructive pulmonary disease.

DESIGN

Systematic review of randomised controlled trials that compared at least two months of regular oral mucolytic drugs with placebo.

STUDIES

Twenty three randomised controlled trials in outpatients in Europe and United States.

MAIN OUTCOME MEASURES

Exacerbations, days of illness, lung function, adverse events.

RESULTS

Compared with placebo, the number of exacerbations was significantly reduced in subjects taking oral mucolytics (weighted mean difference -0.07 per month, 95% confidence interval -0.08 to -0.05, P<0.0001). Based on the annualised rate of exacerbations in the control subjects of 2.7 a year, this is a 29% reduction. The number needed to treat for one subject to have no exacerbation in the study period would be 6. Days of illness also fell (weighted mean difference -0.56, -0.77 to -0.35, P<0.0001). The number of subjects who had no exacerbations in the study period was greater in the mucolytic group (odds ratio 2.22, 95% confidence interval 1.93 to 2.54, P<0.0001). There was no difference in lung function or in adverse events reported between treatments.

CONCLUSIONS

In chronic bronchitis and chronic obstructive pulmonary disease, treatment with mucolytics is associated with a reduction in acute exacerbations and days of illness. As these drugs have to be taken long term, they could be most useful in patients who have repeated, prolonged, or severe exacerbations of chronic obstructive pulmonary disease.

Treatment of chronic obstructive pulmonary disease and its exacerbations in general practice. EOLO Group. Estudio Observacional de la Limitación Obstructiva al Flujo aEreo

The high prevalence and chronicity of chronic obstructive pulmonary disease (COPD) imply that many of these patients are treated and controlled in primary-care centres, often without contact with specialized pneumologist care. We conducted the present study to evaluate the treatment administered in stable and exacerbated COPD in GP-setting clinics and to investigate which factors could be associated with the different prescriptions. This is a cross-sectional observational study of ambulatory COPD patients. General practitioners (n = 201) were selected throughout Spain by regionally stratified sampling. We recorded the physician-reported prescription drug use in ambulatory treatment of stable COPD and acute exacerbations of COPD through a standard questionnaire. Factors independently associated with the prescription of drugs were ascertained by multiple logistic regression analysis. Of 1078 questionnaires reviewed, 1001 fulfilled quality criteria. There were 878 men (88%) and 123 women (12%); 777 (78%) were smokers or ex-smokers with a mean age of 68 years. Mean FEV1 was 47% predicted (% pred.) (SD = 13%). The median number of exacerbations was two per year (range = 0-16). Regular treatment for COPD was received by 878 (88%): the most commonly used drugs were inhaled beta 2-agonists (71%), theophyllines (53%) and inhaled corticosteroids (ICs) (50%), followed by mucolytics (25%), ipratropium bromide (23%), and oral corticosteroids (OCs) (4%). Treatment for exacerbations included inhaled bronchodilators (90%), antibiotics (89%), ICs (71%) and OCs (43%). Impairment of FEV1 was the factor most strongly associated in multiple regression analysis with increasing drug prescription in stable COPD, except for mucolytics, while the number of previous acute exacerbations was the main factor associated with exacerbation treatment except for OCs, the use of which was associated with more impaired pulmonary function. A significant number of the treatments prescribed in primary care for stable and exacerbated COPD do not follow current recommendations. Impairment in FEV1 is the factor most strongly associated with increasing prescription in stable COPD and the number of previous exacerbations is the main factor associated with exacerbation treatment.

Perioperative interventions for prevention of postoperative pulmonary complications: systematic review and meta-analysis

OBJECTIVE

To identify, appraise, and synthesise the best available evidence on the efficacy of perioperative interventions to reduce postoperative pulmonary complications (PPCs) in adult patients undergoing non-cardiac surgery.

DESIGN

Systematic review and meta-analysis of randomised controlled trials.

DATA SOURCES

Medline, Embase, CINHAL, and CENTRAL from January 1990 to December 2017.

ELIGIBILITY CRITERIA

Randomised controlled trials investigating short term, protocolised medical interventions conducted before, during, or after non-cardiac surgery were included. Trials with clinical diagnostic criteria for PPC outcomes were included. Studies of surgical technique or physiological or biochemical outcomes were excluded.

DATA EXTRACTION AND SYNTHESIS

Reviewers independently identified studies, extracted data, and assessed the quality of evidence. Meta-analyses were conducted to calculate risk ratios with 95% confidence intervals. Quality of evidence was summarised in accordance with GRADE methods. The primary outcome was the incidence of PPCs. Secondary outcomes were respiratory infection, atelectasis, length of hospital stay, and mortality. Trial sequential analysis was used to investigate the reliability and conclusiveness of available evidence. Adverse effects of interventions were not measured or compared.

RESULTS

117 trials enrolled 21 940 participants, investigating 11 categories of intervention. 95 randomised controlled trials enrolling 18 062 participants were included in meta-analysis; 22 trials were excluded from meta-analysis because the interventions were not sufficiently similar to be pooled. No high quality evidence was found for interventions to reduce the primary outcome (incidence of PPCs). Seven interventions had low or moderate quality evidence with confidence intervals indicating a probable reduction in PPCs: enhanced recovery pathways (risk ratio 0.35, 95% confidence interval 0.21 to 0.58), prophylactic mucolytics (0.40, 0.23 to 0.67), postoperative continuous positive airway pressure ventilation (0.49, 0.24 to 0.99), lung protective intraoperative ventilation (0.52, 0.30 to 0.88), prophylactic respiratory physiotherapy (0.55, 0.32 to 0.93), epidural analgesia (0.77, 0.65 to 0.92), and goal directed haemodynamic therapy (0.87, 0.77 to 0.98). Moderate quality evidence showed no benefit for incentive spirometry in preventing PPCs. Trial sequential analysis adjustment confidently supported a relative risk reduction of 25% in PPCs for prophylactic respiratory physiotherapy, epidural analgesia, enhanced recovery pathways, and goal directed haemodynamic therapies. Insufficient data were available to support or refute equivalent relative risk reductions for other interventions.

CONCLUSIONS

Predominantly low quality evidence favours multiple perioperative PPC reduction strategies. Clinicians may choose to reassess their perioperative care pathways, but the results indicate that new trials with a low risk of bias are needed to obtain conclusive evidence of efficacy for many of these interventions.

STUDY REGISTRATION

Prospero CRD42016035662.

A review of national guidelines for management of COPD in Europe

The quality of care can be improved by the development and implementation of evidence-based treatment guidelines. Different national guidelines for chronic obstructive pulmonary disease (COPD) exist in Europe and relevant differences may exist among them.This was an evaluation of COPD treatment guidelines published in Europe and Russia in the past 7 years. Each guideline was reviewed in detail and information about the most important aspects of patient diagnosis, risk stratification and pharmacotherapy was extracted following a standardised process. Guidelines were available from the Czech Republic, England and Wales, Finland, France, Germany, Italy, Poland, Portugal, Russia, Spain and Sweden. The treatment goals, criteria for COPD diagnosis, consideration of comorbidities in treatment selection and support for use of long-acting bronchodilators, were similar across treatment guidelines. There were differences in measures used for stratification of disease severity, consideration of patient phenotypes, criteria for the use of inhaled corticosteroids and recommendations for other medications (e.g. theophylline and mucolytics) in addition to bronchodilators.There is generally good agreement on treatment goals, criteria for diagnosis of COPD and use of long-acting bronchodilators as the cornerstone of treatment among guidelines for COPD management in Europe and Russia. However, there are differences in the definitions of patient subgroups and other recommended treatments.

Mucolytics in cystic fibrosis

Mucus accumulation in the lower airways is a key feature of cystic fibrosis (CF) lung disease. The major component of mucus in CF is not mucin derived from mucus producing cells but rather pus that includes viscous material such as polymerized DNA derived from degraded neutrophils. This has important implications for mucolytic therapy aiming to improve mucus clearance from the airways, since degradation of mucin may not be a suitable treatment strategy. In addition, thinning of secretions may not always be beneficial, since it may negatively affect certain aspects of mucus transport such as cough clearance. While inhaled N-acetylcysteine has been used as a mucolytic drug in CF for decades, there is little evidence that it has any beneficial effect. Dornase alfa has been shown to reduce pulmonary exacerbations and improve lung function and is currently the only mucolytic agent with proven efficacy in CF. Newer agents targeting other components of CF mucus, such as filamentous actin, are currently in development. Ultimately, drugs that are mucokinetic, which preserve viscoelasticity, rather than mucolytic may prove to be beneficial for CF lung disease in the future.

Cystic Fibrosis: A Review

Importance

Cystic fibrosis, a genetic disorder defined by variants in the cystic fibrosis transmembrane conductance regulator (CFTR) gene, affects more than 30 000 individuals in the US and approximately 89 000 worldwide. Absent or decreased function of the CFTR protein is associated with multiorgan dysfunction and shortened life expectancy.

Observations

CFTR is an anion channel in the apical membrane of epithelial cells. Loss of function leads to obstructed exocrine glands. Of people with cystic fibrosis in the US, approximately 85.5% have the gene variant F508del. Manifestations of cystic fibrosis in patients with the F508del gene variant begin in infancy with steatorrhea, poor weight gain, and respiratory symptoms (coughing, wheezing). As people with cystic fibrosis age, chronic respiratory bacterial infections cause loss of lung function and bronchiectasis. With the availability of universal newborn screening in multiple countries including the US, many people with cystic fibrosis are asymptomatic at diagnosis. With multidisciplinary care teams that included dietitians, respiratory therapists, and social workers, treatment of cystic fibrosis can slow disease progression. Median survival has improved from 36.3 years (95% CI, 35.1-37.9) in 2006 to 53.1 years (95% CI, 51.6-54.7) in 2021. Pulmonary therapies for patients with cystic fibrosis consist of mucolytics (eg, dornase alfa), anti-inflammatories (eg, azithromycin), and antibiotics (such as tobramycin delivered by a nebulizer). Four small molecular therapies, termed CFTR modulators, that facilitate CFTR production and/or function have received regulatory approval. Examples are ivacaftor and elexacaftor-tezacaftor-ivacaftor. For example, in patients with 1 F508del variant, the combination of ivacaftor, tezacaftor, and elexacaftor improved lung function from -0.2% in the placebo group to 13.6% (difference, 13.8%; 95% CI, 12.1%-15.4%) and decreased the annualized estimated rate of pulmonary exacerbations from 0.98 to 0.37 (rate ratio, 0.37; 95% CI, 0.25-0.55). Improved respiratory function and symptoms have lasted up to 144 weeks in postapproval observational studies. An additional 177 variants are eligible for treatment with the elexacaftor-tezacaftor-ivacaftor combination.

Conclusion

Cystic fibrosis affects approximately 89 000 people worldwide and is associated with a spectrum of disease related to exocrine dysfunction, including chronic respiratory bacterial infections and reduced life expectancy. First-line pulmonary therapies consist of mucolytics, anti-inflammatories, and antibiotics, and approximately 90% of people with cystic fibrosis who are 2 years or older may benefit from a combination of ivacaftor, tezacaftor, and elexacaftor.

Rheology of cystic fibrosis sputum after in vitro treatment with hypertonic saline alone and in combination with recombinant human deoxyribonuclease I

Treatment with recombinant human deoxyribonuclease I (rhDNase) is currently used as therapy for cystic fibrosis (CF) lung disease. Hypertonic saline (HS) acts as an expectorant promoting mucus secretion and augmenting the volume of sputum. We evaluated the individual and combined effects of HS and rhDNase in vitro on the viscoelasticity of CF sputum. Sputum samples were collected from nine CF patients to use for in vitro testing. Aliquots of CF sputum (0.20 to 0.40 g) were subjected to the following protocols: (1) negative control sample without any treatment; (2) positive control sample, adding 10% volume of normal saline (0.9% NaCl); (3) application of hypertonic saline (HS-3% NaCl); (4) combining approximately 100 nM concentration of rhDNase with protocols 2 and 3. The samples in protocols 2 through 4 were incubated for 30 min at 37 degrees C. For each protocol, CF sputum was analyzed at baseline and at 30 min for spinnability by filancemeter and viscoelasticity by magnetic microrheometry. Spinnability decreased for the sputum samples that were treated with rhDNase, in combination with either HS or normal saline. Treatment with HS alone and combined treatment with rhDNase and HS decreased log G* (the principal viscoelasticity index) to the same degree. Saline alone and rhDNase in normal saline both increased the predicted cough clearability of the sputum; however, the combined treatment with rhDNase and hypertonic saline had the best overall effect on cough clearability. The change in predicted mucociliary clearability, although greatest after HS, was not significant. These in vitro results suggest that combined treatment with rhDNase and HS should be evaluated further as a potential mucotropic approach to augment the clearance of purulent sputum in CF lung disease.

Gene transfer to the lung: lessons learned from more than 2 decades of CF gene therapy

Gene therapy is currently being developed for a wide range of acute and chronic lung diseases. The target cells, and to a degree the extra and intra-cellular barriers, are disease-specific and over the past decade the gene therapy community has recognized that no one vector is good for all applications, but that the gene transfer agent (GTA) has to be carefully matched to the specific disease target. Gene therapy is particularly attractive for diseases that currently do not have satisfactory treatment options and probably easier for monogenic disorders than for complex diseases. Cystic fibrosis (CF) fulfils these criteria and is, therefore, a good candidate for gene therapy-based treatment. This review will focus on CF as an example for lung gene therapy, but lessons learned may be applicable to other target diseases.

Pseudomonas aeruginosa aggregates in cystic fibrosis sputum produce exopolysaccharides that likely impede current therapies

In cystic fibrosis (CF) airways, Pseudomonas aeruginosa forms cellular aggregates called biofilms that are thought to contribute to chronic infection. To form aggregates, P. aeruginosa can use different mechanisms, each with its own pathogenic implications. However, how they form in vivo is controversial and unclear. One mechanism involves a bacterially produced extracellular matrix that holds the aggregates together. Pel and Psl exopolysaccharides are structural and protective components of this matrix. We develop an immunohistochemical method to visualize Pel and Psl in CF sputum. We demonstrate that both exopolysaccharides are expressed in the CF airways and that the morphology of aggregates is consistent with an exopolysaccharide-dependent aggregation mechanism. We reason that the cationic exopolysaccharide Pel may interact with some of the abundant anionic host polymers in sputum. We show that Pel binds extracellular DNA (eDNA) and that this interaction likely impacts current therapies by increasing antimicrobial tolerance and protecting eDNA from digestion.