Ventricular arrhythmia, Cheyne-Stokes respiration, and death: observations from patients with defibrillators

OBJECTIVE

To determine whether ventricular arrhythmia related to nocturnal hypoxaemia during Cheyne-Stokes respiration (CSR) explains the observation that CSR is an independent marker of death in heart failure.

DESIGN

Prospective, observational study.

PATIENTS

101 patients at high risk of clinical serious ventricular arrhythmia fitted with an implantable cardioverter-defibrillator (ICD).

MEASUREMENTS

Patients were studied at baseline for CSR during sleep. Arrhythmia requiring device discharge was used as a surrogate marker for possible sudden cardiac death.

RESULTS

101 patients (42 with CSR) were followed up for a total of 620 months. Twenty six patients experienced 432 ICD discharge episodes. Twenty four (6%), 210 (49%), 125 (29%), and 73 (17%) episodes occurred across the time quartiles 0000-0559, 0600-1159, 1200-1759, and 1800-2359, respectively. Kaplan-Meier analysis showed a relative risk of 1 (95% confidence interval 0.5 to 2.2, p = 1) for device discharge in the CSR group. The average (SED) numbers of nocturnal ICD discharges per patient per month of follow up were 0.01 (0.01) and 0.04 (0.02) for patients with and without CSR, respectively (p = 0.6).

CONCLUSION

These findings refute the proposition that CSR is related to heart failure death through nocturnal serious ventricular arrhythmia.

Epidemiological relationships between the common cold and exacerbation frequency in COPD

Higher exacerbation incidence rates in chronic obstructive pulmonary disease (COPD) are associated with more rapid decline in lung function and poorer quality of life, yet the mechanisms determining susceptibility to exacerbation remain ill-defined. The same viruses responsible for common colds are frequently isolated during exacerbations. The current authors hypothesised that exacerbation frequency may be associated with an increased frequency of colds, and investigated whether increased exacerbation frequency was associated with increased acquisition of colds, or a greater likelihood of exacerbation once a cold has been acquired. A total of 150 patients with COPD completed diary cards recording peak expiratory flow, and respiratory and coryzal symptoms for a median 1,047 days. Annual cold and exacerbation incidence rates (cold and exacerbation frequency) were calculated, and the relationships between these variables were investigated. This analysis is based on 1,005 colds and 1,493 exacerbations. Frequent exacerbators (i.e. those whose exacerbation frequency was greater than the median) experienced significantly more colds than infrequent exacerbators (1.73 versus 0.94.yr(-1)). The likelihood of exacerbation during a cold was unaffected by exacerbation frequency. Patients experiencing frequent colds had a significantly higher exposure to cigarette smoke (46 versus 33 pack-yrs). Exacerbation frequency in chronic obstructive pulmonary disease is associated with an increased frequency of acquiring the common cold, rather than an increased propensity to exacerbation once a cold has been acquired.

Patterns of home mechanical ventilation use in Europe: results from the Eurovent survey

The study was designed to assess the patterns of use of home mechanical ventilation (HMV) for patients with chronic respiratory failure across Europe. A detailed questionnaire of centre details, HMV user characteristics and equipment choices was sent to carefully identified HMV centres in 16 European countries. A total of 483 centres treating 27,118 HMV users were identified. Of these, 329 centres completed surveys between July 2001 and June 2002, representing up to 21,526 HMV users and a response rate of between 62% and 79%. The estimated prevalence of HMV in Europe was 6.6 per 100,000 people. The variation in prevalence between countries was only partially related to the median year of starting HMV services. In addition, there were marked differences between countries in the relative proportions of lung and neuromuscular patients using HMV, and the use of tracheostomies in lung and neuromuscular HMV users. Lung users were linked to a HMV duration of <1 yr, thoracic cage users with 6-10 yrs of ventilation and neuromuscular users with a duration of > or =6 yrs. In conclusion, wide variations exist in the patterns of home mechanical ventilation provision throughout Europe. Further work is needed to monitor its use and ensure equality of provision and access.

Non-invasive positive pressure ventilation for treatment of respiratory failure due to severe acute exacerbations of asthma

BACKGROUND

Non-invasive positive pressure ventilation (NPPV) has been shown to be effective in chronic obstructive pulmonary disease patients with acute respiratory failure. However, its role in patients with severe acute asthma is uncertain. The pathophysiologic condition of acute respiratory failure in asthma is in many ways similar to that of acute respiratory failure in COPD. Therefore, there is reason to believe that NPPV could also be successful in patients with severe acute asthma.

OBJECTIVES

To determine the efficacy of NPPV in adults with severe acute asthma in comparison to usual medical care with respect to mortality, tracheal intubation, changes in blood gases and hospital length of stay.

SEARCH STRATEGY

An initial search for studies was carried out using CENTRAL. Additional searches were also carried out on MEDLINE, EMBASE, CINAHL, Science Citation, web based clinical trials databases and key journals with web sites were also searched as well as respiratory conference proceedings. Following this, the bibliographies of each randomised controlled trial obtained (and any review articles) was searched for additional studies. Date of most recent search for trials was conducted on May 2004.

SELECTION CRITERIA

Only RCTs in adults patients with severe acute asthma were considered for inclusion. Studies including patients with features of COPD were excluded unless data was provided separately for patients with asthma in studies recruiting both COPD and asthma patients.

DATA COLLECTION AND ANALYSIS

All data was analysed using RevMan. For continuous variables, a weighted mean difference and 95% confidence interval (95%CI) was calculated for each study outcome. For dichotomous variables relative risk with 95% confidence interval was calculated.

MAIN RESULTS

From an initial search of 696 abstracts, 11 trials were obtained in full-text for closer examination. Ten trials were excluded and one included. The one included trial, on 30 patients, showed benefit with NPPV when compared to usual medical care alone with significant improvements in hospitalisation rate, number of patients discharged from emergency department, percent predicted FEV(1), FVC, PEFR and respiratory rate.

AUTHORS' CONCLUSIONS

The application of NPPV in patients suffering from status asthmaticus, despite some interesting and very promising preliminary results, still remains controversial. Large, prospective, randomised controlled trials are therefore needed to determine the role of NPPV in status asthmaticus.

Quality control of equipment in home mechanical ventilation: a European survey

Quality control of the equipment used in home mechanical ventilation is necessary in order to ensure that patients safely and accurately receive the prescribed ventilatory support. The aim of this study was to carry out a survey on the quality-control procedures in different centres and countries. The survey was carried out in the context of a European Commission Concerted Action covering 16 European countries. The study was extensive and detailed, involving 326 centres, which provided home ventilation to >20,000 patients. The survey showed that: 1) ventilator servicing was mainly carried out by external companies (62% of centres), with a servicing frequency ranging 3-12 months; 2) interaction between servicing companies and prescribers was limited (only 61% of centres were always informed of major incidents); 3) participation of centres in equipment quality control was poor (only 56% of centres assessed that patients/caregivers correctly cleaned/maintained the ventilator); and 4) centres were insufficiently aware of vigilance systems (only 23% of centres). Moreover, the data showed considerable inter- and intra-country differences. The size of the centre was an important determinant of many of these quality-control aspects. This survey provides information that will enable the European Commission Concerted Action to formulate recommendations on procedures for home-ventilator quality control.

Non-invasive positive pressure ventilation for treatment of respiratory failure due to severe acute exacerbations of asthma

BACKGROUND

Non-invasive positive pressure ventilation (NPPV) has been shown to be effective in chronic obstructive pulmonary disease (COPD) patients with acute respiratory failure. However, its role in patients with severe acute asthma is uncertain. The pathophysiologic condition of acute respiratory failure in asthma is in many ways similar to that of acute respiratory failure in COPD. Therefore, there is reason to believe that NPPV could also be successful in patients with severe acute asthma.

OBJECTIVES

To determine the efficacy of NPPV in adults with severe acute asthma, in comparison to usual medical care, with respect to mortality, tracheal intubation, changes in blood gases, and hospital length of stay.

SEARCH STRATEGY

An initial search for studies was carried out using the Cochrane Controlled Trials Register (CENTRAL). Additional searches were carried out on MEDLINE, EMBASE, CINAHL, Science Citation and web based clinical trials databases. Key journals with web sites were also searched as well as respiratory conference proceedings. Following this, the bibliographies of each randomised controlled trial obtained (and any review articles) were searched for additional studies. The date of the most recent search for trials was May 2004.

SELECTION CRITERIA

All data were analysed using RevMan. For continuous variables a weighted mean difference and 95% confidence interval (95% CI) was calculated for each study outcome. For dichotomous variables relative risk with 95% confidence interval was calculated.

DATA COLLECTION AND ANALYSIS

All data was analysed using RevMan. For continuous variables, a weighted mean difference and 95% confidence interval (95%CI) was calculated for each study outcome. For dichotomous variables relative risk with 95% confidence interval was calculated.

MAIN RESULTS

From an initial search of 696 abstracts, 11 trials were obtained in full text for closer examination. Ten trials were excluded and one included. The one included trial, on 30 patients, showed benefit with NPPV when compared to usual medical care alone, with significant improvements in hospitalisation rate, number of patients discharged from emergency department, percent predicted forced expiratory volume in one minute (FEV1), forced vital capacity (FVC), peak expiratory flow rate (PEFR) and respiratory rate.

AUTHORS' CONCLUSIONS

The application of NPPV in patients suffering from status asthmaticus, despite some interesting and very promising preliminary results, still remains controversial. Large, prospective randomised controlled trials are therefore needed to determine the role of NPPV in status asthmaticus.

Chronic obstructive pulmonary disease: the clinical management of an acute exacerbation

Exacerbations of chronic obstructive pulmonary disease impose a considerable burden of morbidity, mortality, and health care cost. Management guidelines outlining best practice, based largely on consensus expert opinion, were produced by a number of organisations during the last decade. Current interest in the field is high. This has resulted in the publication of many further studies which have extended our understanding of the pathology involved and provided, for the first time, an evidence base for many of the therapeutic options. In this review we aim to bring the non-specialist reader up to date with current management principles and the evidence underlying such interventions.

Obstructive sleep apnea presenting as pseudopheochromocytoma: a case report

Sudden arousal from sleep causes a transient surge in sympathetic nervous activity. Repeated arousals, as occur in obstructive sleep apnea (OSA), are well documented to cause a more prolonged sympathetic overactivity and consequent elevations in 24-h urinary catecholamine levels. We describe here a series of five patients, each presenting with a clinical and biochemical picture indistinguishable from that of pheochromocytoma. Thorough investigations have failed to find catecholamine-secreting tumor in any of these subjects, but all have been diagnosed with OSA. Primary treatment of OSA with nasal continuous positive airways pressure has led to normalization of systemic blood pressure and urinary catecholamines. Pseudopheochromocytoma is therefore a rare, but treatable, presentation of obstructive sleep apnea.

Non-invasive positive pressure ventilation for treatment of respiratory failure due to exacerbations of chronic obstructive pulmonary disease

BACKGROUND

Non-invasive positive pressure ventilation (NPPV) is being used increasingly in the management of patients admitted to hospital with acute respiratory failure secondary to an exacerbation of chronic obstructive pulmonary disease (COPD).

OBJECTIVES

To determine the efficacy of NPPV in the management of patients with respiratory failure due to an acute exacerbation of COPD.

SEARCH STRATEGY

An initial search was performed using the Cochrane Airways Group trials register and other relevant electronic databases. An updated search was conducted in September 2003 and another in April 2004.

SELECTION CRITERIA

Randomised controlled trials comparing NPPV plus usual medical care (UMC) versus UMC alone were selected. Trials needed to recruit adult patients admitted to hospital with respiratory failure due to an exacerbation of COPD and with PaCO2 > 6 kPa (45 mmHg).

DATA COLLECTION AND ANALYSIS

Two reviewers independently selected articles for inclusion, evaluated methodological quality of the studies and abstracted the data.

MAIN RESULTS

Fourteen studies were included in the review. NPPV resulted in decreased mortality (Relative Risk 0.52; 95%CI 0.35 to 0.76), decreased need for intubation (RR 0.41; 95%CI 0.33 to 0.53), reduction in treatment failure (RR 0.48; 95%CI 0.37 to 0.63), rapid improvement within the first hour in pH (Weight Mean Difference 0.03; 95%CI 0.02 to 0.04), PaCO2 (WMD -0.40 kPa; 95%CI -0.78 to -0.03) and respiratory rate (WMD -3.08 bpm; 95%CI -4.26 to -1.89). In addition, complications associated with treatment (RR 0.38; 95%CI 0.24 to 0.60) and length of hospital stay (WMD -3.24 days; 95%CI -4.42 to -2.06) was also reduced in the NPPV group.

REVIEWERS' CONCLUSIONS

Data from good quality randomised controlled trials show benefit of NPPV as first line intervention as an adjunct therapy to usual medical care in all suitable patients for the management of respiratory failure secondary to an acute exacerbation of COPD. NPPV should be considered early in the course of respiratory failure and before severe acidosis ensues, as a means of reducing the likelihood of endotracheal intubation, treatment failure and mortality.

Non-invasive positive pressure ventilation for treatment of respiratory failure due to exacerbations of chronic obstructive pulmonary disease

BACKGROUND

Non-invasive positive pressure ventilation (NPPV) is being used increasingly in the management of patients admitted to hospital with acute respiratory failure secondary to an exacerbation of chronic obstructive pulmonary disease (COPD).

OBJECTIVES

To determine the efficacy of NPPV in the management of patients with respiratory failure due to an acute exacerbation of COPD.

SEARCH STRATEGY

An initial search was performed using the Cochrane Airways Group trials register and other relevant electronic databases. An updated search was conducted in September 2003.

SELECTION CRITERIA

Randomised controlled trials comparing NPPV plus usual medical care (UMC) versus UMC alone were selected. Trials needed to recruit adult patients admitted to hospital with respiratory failure due to an exacerbation of COPD and with PaCO(2) > 6 kPa (45 mmHg).

DATA COLLECTION AND ANALYSIS

Two reviewers independently selected articles for inclusion, evaluated methodological quality of the studies and abstracted the data.

MAIN RESULTS

Fourteen studies were included in the review. NPPV resulted in decreased mortality (Relative Risk 0.52; 95%CI 0.35, 0.76), decreased need for intubation (RR 0.41; 95%CI 0.33, 0.53), reduction in treatment failure (RR 0.48; 95%CI 0.37, 0.63), rapid improvement within the first hour in pH (Weight Mean Difference 0.03; 95%CI 0.02, 0.04), PaCO(2) (WMD -0.40 kPa; 95%CI -0.78, -0.03) and respiratory rate (WMD -3.08 bpm; 95%CI -4.26, -1.89). In addition, complications associated with treatment (RR 0.38; 95%CI 0.24, 0.60) and length of hospital stay (WMD -3.24 days; 95%CI -4.42, -2.06) was also reduced in the NPPV group.

REVIEWER'S CONCLUSIONS

Data from good quality randomised controlled trials show benefit of NPPV as first line intervention as an adjunct therapy to usual medical care in all suitable patients for the management of respiratory failure secondary to an acute exacerbation of COPD. NPPV should be considered early in the course of respiratory failure and before severe acidosis ensues, as a means of reducing the likelihood of endotracheal intubation, treatment failure and mortality.

Longitudinal changes in the nature, severity and frequency of COPD exacerbations

Exacerbations are an important feature and outcome measure in chronic obstructive pulmonary disease (COPD), but little is known about changes in their severity, recovery, symptom composition or frequency over time. In this study 132 patients (91 male; median age 68.4 yrs and median forced expiratory volume in one second (FEV1) 38.4% predicted) recorded daily symptoms and morning peak expiratory flow. Patients were monitored for a median of 918 days and 1,111 exacerbations were identified. Patients with severe COPD (Global Initiative for Chronic Obstructive Lung Disease (GOLD) category III, n=38) had an annual exacerbation frequency of 3.43 x yr(-1), 0.75 x yr(-1) higher than those with moderate COPD (GOLD II, n=94). Exacerbation frequency did not change significantly during the study. At exacerbation onset, symptom count increased to 2.23, relative to a baseline of 0.36 set 8-14 days previously, and this increase rose by 0.05 x yr(-1). Recovery to baseline levels in symptoms and FEV1 took longer (0.32 and 0.55 days x yr(-1)). Sputum purulence at exacerbation became more prevalent over time by 4.1% x yr(-1) from an initial value of 17%. The results of this study suggest that over time, individual patients have more symptoms during exacerbations, with an increased chance of sputum purulence and longer recovery times.

Airway epithelial inflammatory responses and clinical parameters in COPD

This study examined inflammatory responses from primary cultured human bronchial epithelial cells in chronic obstructive pulmonary disease (COPD) and the clinical factors modulating them. Epithelial cells from bronchoscopic biopsies from 14 patients with COPD ((mean +/- SD) age 74.6 +/- 5.7 yrs, forced expiratory volume in one second (FEV1) 1.21 +/- 0.36 L, FEV1 %, predicted 51.1 +/- 15.8%, 51.5 +/- 24.0 pack-yrs of smoking, inhaled steroid dosage 1237.5 +/- 671.0 microg x day(-1), Medical Research Council (MRC) dyspnoea score 3.18 +/- 1.33) and eight current/exsmokers with normal pulmonary function (age 60.4 +/- 13.5 yrs, FEV1 2.66 +/- 1.27 L, FEV1 % pred 89.6 +/- 17.7%, 49 +/- 44 pack-yrs of smoking, MRC dyspnoea score 1 +/- 0) were grown in primary culture and exposed to 50 ng x mL(-1) tumour necrosis factor-alpha. Stimulated COPD cells produced significantly more interleukin (IL)-6 at 24 and 48 h, and IL-8 at 6 and 24 h than unstimulated COPD cells. This response was not seen in cells from current/exsmokers. IL-6 and IL-8 production was lower in COPD patients taking inhaled steroids. Following an inflammatory stimulus, bronchial epithelial cells in chronic obstructive pulmonary disease show a significant cytokine response not seen in smokers with normal pulmonary function and this may be modified by inhaled steroid therapy.

COPD exacerbations: definitions and classifications

Chronic obstructive pulmonary disease (COPD) is defined independently of exacerbations, which are largely a feature of moderate-to-severe disease. This article is the result of a workshop that tried to define exacerbations of COPD for use in clinical, pharmacological and epidemiological studies. The conclusions represent the consensus of those present. This review describes definitions, ascertainment, severity assessments, duration and frequency, using varying sources of data including direct patient interview, healthcare databases and symptom diaries kept by patients in studies. The best general definition of a COPD exacerbation is the following: an exacerbation of COPD is a sustained worsening of the patient's condition, from the stable state and beyond normal day-to-day variations that is acute in onset and may warrant additional treatment in a patient with underlying COPD. A more specific definition for studies where a bacteriological cause of exacerbation is being studied is included, as well as simpler definitions for retrospective identification from database sources. Prospective diary card assessments are best recorded as changes from an agreed baseline, rather than absolute symptom severities. Diary cards identify many unreported exacerbations, which on average have similar severities to reported exacerbations. A scale for exacerbation severity is proposed that incorporates in- and outpatient assessments. Exacerbation duration, which also relates to severity, is defined from diary card reports. Healthcare utilisation is not an adequate substitute for severity, depending on many unrelated social and comorbidity factors. It is an outcome in its own right.

Non-invasive positive pressure ventilation for treatment of respiratory failure due to exacerbations of chronic obstructive pulmonary disease

BACKGROUND

Non-invasive positive pressure ventilation (NPPV) is being used increasingly in the management of patients admitted to hospital with acute respiratory failure secondary to an exacerbation of chronic obstructive pulmonary disease (COPD).

OBJECTIVES

To determine the effectiveness of NPPV in the management of patients with respiratory failure due to an acute exacerbation of COPD.

SEARCH STRATEGY

An initial search was performed using the Cochrane Airways Group trials register and other relevant electronic databases.

SELECTION CRITERIA

Randomised controlled trials comparing NPPV plus usual medical care versus usual medical care alone were selected. Trials needed to recruit adult patients admitted to hospital with respiratory failure due to an exacerbation of COPD and with PaCO2 > 6 kPa (45 mmHg).

DATA COLLECTION AND ANALYSIS

Two reviewers independently selected articles for inclusion, evaluated methodological quality of the studies and abstracted the data.

MAIN RESULTS

Eight studies were included in the review. NPPV resulted in decreased mortality (Relative Risk [RR] 0.41; 95% Confidence Intervals [CI] 0.26, 0.64), decreased need for intubation (RR 0.42; 95%CI 0.31, 0.59), reduction in treatment failure (RR 0.51; 95%CI 0.39, 0.67), rapid improvement within the first hour in pH (Weight Mean Difference [WMD] 0.03; 95%CI 0.02, 0.04), PaCO2 (WMD -0.40 kPa; 95%CI -0.78, -0.03) and respiratory rate (WMD -3.08 bpm; 95%CI -4.26, -1.89). In addition, complications associated with treatment (RR 0.32; 95%CI 0.18, 0.56) and length of hospital stay (WMD -3.24 days; 95%CI -4.42, -2.06) were also reduced in the NPPV group.

REVIEWER'S CONCLUSIONS

Data from good quality randomised controlled trials permit NPPV to be recommended as the first line intervention, coupled with usual medical care, in all suitable patients with respiratory failure secondary to an acute exacerbation of COPD. A trial of NPPV should be considered early in the course of respiratory failure, and before severe acidosis ensures, as a means of avoiding endotracheal intubation, reducing mortality and treatment failure.

Hospital at home for acute exacerbations of chronic obstructive pulmonary disease

BACKGROUND

Hospital at home schemes are a recently adopted method of service delivery for the management of acute exacerbations of chronic obstructive pulmonary disease aimed at reducing demand for acute hospital in-patient beds and promoting a patient centered approach through admission avoidance. However, evidence in support of such a service is contradictory.

OBJECTIVES

To evaluate the efficacy of "hospital at home" compared to hospital inpatient care in acute exacerbations of chronic obstructive pulmonary disease.

SEARCH STRATEGY

The Cochrane Central Register of Controlled Trials; electronically available databases e.g. MEDLINE (1966-current), EMBASE (1980-current), PubMed, ClincalTrials, Science Citation Index and on-line individual respiratory journals; bibliographies of included trials were all searched and contact with authors was made to obtain studies. The most recent searches were carried out in August 2003.

SELECTION CRITERIA

Only randomised controlled trials were considered where patients presented to the emergency department with an exacerbation of their chronic obstructive pulmonary disease. Studies must not have recruited patients that are usually deemed obligatory admissions.

DATA COLLECTION AND ANALYSIS

Two reviewers independently selected articles for inclusion, evaluated methodological quality of the studies and abstracted data.

MAIN RESULTS

Seven studies with 754 patients were included in the review. Studies provided data on hospital readmission and mortality both of which were not significantly different when the two study groups were compared (RR 0.89; 95%CI 0.72 to 1.12 & RR 0.61; 95%CI 0.36 to 1.05, respectively). Both the patients and the carers preferred hospital at home schemes to inpatient care (RR 1.53; 95%CI 1.23 to 1.90). Other reported outcomes included few studies.

REVIEWER'S CONCLUSIONS

This review has shown that one in four carefully selected patients presenting to hospital emergency departments with acute exacerbations of chronic obstructive pulmonary disease can be safely and successfully treated at home with support from respiratory nurses. This review found no evidence of significant differences between "hospital at home" patients and hospital inpatients for readmission rates and mortality at two to three months after the initial exacerbation. Both the patients and carers preferred "hospital at home" schemes to inpatient care.

Relationship between exacerbation frequency and lung function decline in chronic obstructive pulmonary disease

BACKGROUND

Chronic obstructive pulmonary disease (COPD) is characterised by both an accelerated decline in lung function and periods of acute deterioration in symptoms termed exacerbations. The aim of this study was to investigate whether these are related.

METHODS

Over 4 years, peak expiratory flow (PEF) and symptoms were measured at home daily by 109 patients with COPD (81 men; median (IQR) age 68.1 (63-74) years; arterial oxygen tension (PaO(2)) 9.00 (8.3-9.5) kPa, forced expiratory volume in 1 second (FEV(1)) 1.00 (0.7-1.3) l, forced vital capacity (FVC) 2.51 (1.9-3.0) l); of these, 32 (29 men) recorded daily FEV(1). Exacerbations were identified from symptoms and the effect of frequent or infrequent exacerbations (> or < 2.92 per year) on lung function decline was examined using cross sectional, random effects models.

RESULTS

The 109 patients experienced 757 exacerbations. Patients with frequent exacerbations had a significantly faster decline in FEV(1) and peak expiratory flow (PEF) of -40.1 ml/year (n=16) and -2.9 l/min/year (n=46) than infrequent exacerbators in whom FEV(1) changed by -32.1 ml/year (n=16) and PEF by -0.7 l/min/year (n=63). Frequent exacerbators also had a greater decline in FEV(1) if allowance was made for smoking status. Patients with frequent exacerbations were more often admitted to hospital with longer length of stay. Frequent exacerbations were a consistent feature within a patient, with their number positively correlated (between years 1 and 2, 2 and 3, 3 and 4).

CONCLUSIONS

These results suggest that the frequency of exacerbations contributes to long term decline in lung function of patients with moderate to severe COPD.

Noninvasive ventilation in chronic obstructive pulmonary disease, bronchiectasis and cystic fibrosis

Although long-term oxygen therapy (LTOT) improves survival, it has little effect on hypoventilation and other outcomes in patients with hypercapnic respiratory failure due to chronic obstructive pulmonary disease (COPD). Recent studies have shown that the use of noninvasive positive-pressure ventilation, when used in combination with LTOT in selected stable COPD patients, controls hypoventilation and improves daytime arterial blood gases, sleep quality, health status and may have a benefit in reducing exacerbation frequency and severity. Patients who show the greatest reduction in overnight carbon dioxide tension in arterial blood with ventilation are most likely to benefit from long-term ventilatory support. Some benefits have also been shown in patients with chronic respiratory failure due to bronchiectasis and cystic fibrosis, though survival is inferior in this patient group. As most studies of noninvasive positive-pressure ventilation in chronic obstructive pulmonary disease have been relatively short term, large multicentre studies with survival, exacerbations and hospital admissions as the primary end points are required to evaluate longer term effects.

An evaluation of the reliability and sensitivity of the London Chest Activity of Daily Living Scale (LCADL)

We have previously reported the validity of a new assessment tool; the London Chest Activity of Daily Living Scale (LCADL). This work investigates the reliability and responsiveness of that measure. Reliability was assessed in 19 patients with stable severe chronic obstructive pulmonary disease (COPD); median age (range) 66 (55-79) years, FEV1 mean (SD) 0.91 (0.29) l, by test-retest 4 weeks apart. Responsiveness was assessed in 59 patients; median age (range) 66 (38-84) years, FEV1 mean (SD) 0.87 (0.30) l, who had undergone at least 6 weeks of pulmonary rehabilitation. Test-retest scores of the LCADL showed a strong relationship with one another, Intraclass correlation coefficient Icc=0.93 95%CI (0.82-0.97) demonstrating evidence of good reliability. With the exception of the Domestic component, all domains of the LCADL showed a statistically significant reduction in dyspnoea during ADLs after pulmonary rehabilitation. There was a statistically significant improvement in the total LCADL score (mean difference (95% CI) -5.91 (from -9.23 to -2.60) after rehabilitation. These data support the use of the LCADL as an outcome measure in COPD which is valid, reliable and responsive to change.

Relationship between bacterial colonisation and the frequency, character, and severity of COPD exacerbations

BACKGROUND

Patients with chronic obstructive pulmonary disease (COPD) are prone to frequent exacerbations which are a significant cause of morbidity and mortality. Stable COPD patients often have lower airway bacterial colonisation which may be an important stimulus to airway inflammation and thereby modulate exacerbation frequency.

METHODS

Twenty nine patients with COPD (21 men, 16 current smokers) of mean (SD) age 65.9 (7.84) years, forced expiratory volume in 1 second (FEV(1)) 1.06 (0.41) l, FEV(1) % predicted 38.7 (15.2)%, FEV(1)/FVC 43.7 (14.1)%, inhaled steroid dosage 1.20 (0.66) mg/day completed daily diary cards for symptoms and peak flow over 18 months. Exacerbation frequency rates were determined from diary card data. Induced sputum was obtained from patients in the stable state, quantitative bacterial culture was performed, and cytokine levels were measured.

RESULTS

Fifteen of the 29 patients (51.7%) were colonised by a possible pathogen: Haemophilus influenzae (53.3%), Streptococcus pneumoniae (33.3%), Haemophilus parainfluenzae (20%), Branhamella catarrhalis (20%), Pseudomonas aeruginosa (20%). The presence of lower airway bacterial colonisation in the stable state was related to exacerbation frequency (p=0.023). Patients colonised by H influenzae in the stable state reported more symptoms and increased sputum purulence at exacerbation than those not colonised. The median (IQR) symptom count at exacerbation in those colonised by H influenzae was 2.00 (2.00-2.65) compared with 2.00 (1.00-2.00) in those not colonised (p=0.03). The occurrence of increased sputum purulence at exacerbation per patient was 0.92 (0.56-1.00) in those colonised with H influenzae and 0.33 (0.00-0.60) in those not colonised (p=0.02). Sputum interleukin (IL)-8 levels correlated with the total bacterial count (rho=0.459, p=0.02).

CONCLUSION

Lower airway bacterial colonisation in the stable state modulates the character and frequency of COPD exacerbations.

Ambulatory oxygen for chronic obstructive pulmonary disease

BACKGROUND

Little is known about the effectiveness of ambulatory domicilary oxygen therapy. At present ambulatory oxygen in the UK is provided with small oxygen cylinders but in other countries such as the USA and Italy, liquid oxygen systems with higher oxygen carrying capacity are widely used. Both these systems are used without adequate evidence of their effectiveness.

OBJECTIVES

To determine the effectiveness of long-term ambulatory domicilary oxygen therapy in patients with chronic obstructive pulmonary disease.

SEARCH STRATEGY

The Cochrane Airways Group specialised trials register was searched. In addition, bibliographies of each trial retrieved were also searched for additional papers that may contain further studies. Authors of identified trials were contacted for other published and unpublished studies.

SELECTION CRITERIA

Only randomised controlled trials in patients with chronic obstructive pulmonary disease were considered for inclusion. Trials must have randomised patients into long-term ambulatory oxygen therapy or placebo while at home. Ambulatory oxygen can be provided either through portable oxygen cylinders or with liquid oxygen canisters and the placebo group using compressed or liquid air.

DATA COLLECTION AND ANALYSIS

Two reviewers assessed all potential trials independently. Data abstraction was completed by one reviewer and re-checked by the second reviewer.

MAIN RESULTS

Only two studies met the inclusion criteria. These provided data on 70 patients. Statistically significant effects of oxygen were found in only one of the studies, a crossover trial involving 9 patients with severe hypoxia at rest. This study reported a reduction in minute ventilation at maximal exercise (WMD -11.00 L/min; 95%CI -17.53, -4.47L/min) and an increase in PaO2 at rest (WMD 17.00 mmHg; 95%CI 9.13,24.87 L/min) with oxygen therapy when compared to placebo. The other study recruited patients who did not have resting hypoxaemia.

REVIEWER'S CONCLUSIONS

Evidence available to date does not allow any firm conclusions to be drawn concerning the effectiveness of ambulatory domicilary oxygen therapy in patients with COPD. Further studies are required in order to understand the role of ambulatory oxygen in the management of patients with COPD on long-term oxygen therapy. These studies should separate patients who desaturate from those who do not desaturate.

Respiratory viruses, symptoms, and inflammatory markers in acute exacerbations and stable chronic obstructive pulmonary disease

The effects of respiratory viral infection on the time course of chronic obstructive pulmonary disease (COPD) exacerbation were examined by monitoring changes in systemic inflammatory markers in stable COPD and at exacerbation. Eighty-three patients with COPD (mean [SD] age, 66.6 [7.1] yr, FEV(1), 1.06 [0.61] L) recorded daily peak expiratory flow rate and any increases in respiratory symptoms. Nasal samples and blood were taken for respiratory virus detection by culture, polymerase chain reaction, and serology, and plasma fibrinogen and serum interleukin-6 (IL-6) were determined at stable baseline and exacerbation. Sixty-four percent of exacerbations were associated with a cold occurring up to 18 d before exacerbation. Seventy-seven viruses (39 [58.2%] rhinoviruses) were detected in 66 (39.2%) of 168 COPD exacerbations in 53 (64%) patients. Viral exacerbations were associated with frequent exacerbators, colds with increased dyspnea, a higher total symptom count at presentation, a longer median symptom recovery period of 13 d, and a tendency toward higher plasma fibrinogen and serum IL-6 levels. Non-respiratory syncytial virus (RSV) respiratory viruses were detected in 11 (16%), and RSV in 16 (23.5%), of 68 stable COPD patients, with RSV detection associated with higher inflammatory marker levels. Respiratory virus infections are associated with more severe and frequent exacerbations, and may cause chronic infection in COPD. Prevention and early treatment of viral infections may lead to a decreased exacerbation frequency and morbidity associated with COPD.

Mechanisms of exacerbations

Exacerbations of chronic obstructive pulmonary disease (COPD) are a major cause of morbidity and mortality and hospital admission. Some patients are particularly susceptible to develop frequent exacerbations; exacerbation frequency being an important determinant of health related quality of life. Patients with frequent exacerbations (three or more exacerbations per year) have increased induced sputum cytokine interleukin (IL)-6 and IL-8 levels when stable, suggesting that frequent exacerbation is associated with increased airway inflammatory changes. Respiratory viral infections are a major cause of COPD exacerbations, with upper respiratory tract infections (colds) being associated with two-thirds of COPD exacerbations. Rhinovirus has been detected in induced sputum by PCR in 25% of exacerbations, suggesting that rhinovirus may directly infect the lower airway triggering exacerbation. The presence of an upper respiratory tract infection leads to a longer symptom recovery time at exacerbation. At exacerbation induced sputum IL-6 levels were increased compared to stable, though there were no significant increases in IL-8 or sputum cell counts. Sputum IL-6 levels were found to be higher in those patients with symptoms of a common cold. Increased airway eosinophilia has been also found at exacerbation. Other factors including bacterial colonization of the airways, temperature and interactions with environmental pollutants may also play a role in COPD exacerbation.

Sputum and plasma endothelin-1 levels in exacerbations of chronic obstructive pulmonary disease

BACKGROUND

Endothelin (ET)-l is a bronchoconstrictor peptide produced in the airways. It has been implicated in the pathogenesis of asthma and virally mediated airway inflammation and may play a role in exacerbations of chronic obstructive pulmonary disease (COPD).

METHODS

Seventy one patients with COPD were followed prospectively and sampled for plasma and sputum ET-1 levels when stable and during an exacerbation. Sputum was also examined for cytokines, human rhinovirus, and Chlamydia pneumoniae.

RESULTS

Plasma ET-1 levels were available for 67 patients with stable COPD (mean (SD) 0.58 (0.31) pg/ml); 28 pairs of stable-exacerbation plasma samples had a mean stable ET-1 level of 0.54 (0.30) pg/ml rising to 0.67 (0.35) pg/ml at exacerbation (mean difference 0.13, 95% confidence interval (CI) 0.04 to 0.21, p = 0.004). Plasma ET-1 levels in the 67 patients with stable COPD were inversely correlated with baseline forced expiratory volume in one second (FEV(1); r = -0. 29, p = 0.022) and forced vital capacity (FVC; r = -0.38, p = 0.002). The change in plasma ET-1 levels during an exacerbation correlated with the change in oxygen saturation (SaO(2); r = -0.41, p = 0.036). In 14 stable-exacerbation pairs of sputum samples median stable ET-1 levels were 5.37 (0.97-21.95) pg/ml rising to 34.68 (13.77-51.95) pg/ml during an exacerbation (mean difference 25.14, 95% CI 3.77 to 46.51, p = 0.028). This increase in sputum ET-1 levels correlated with the increase in plasma ET-1 levels (r = 0.917, p = 0.001) and sputum interleukin (IL)-6 levels (r = 0.718, p = 0.013).

CONCLUSIONS

Sputum levels of ET-1 rise in COPD patients during an exacerbation and this is reflected by a smaller rise in plasma ET-1 levels. ET-1 may have a role in mediating airway inflammatory changes during exacerbations of COPD.

Detection of rhinovirus in induced sputum at exacerbation of chronic obstructive pulmonary disease

Common colds are associated with exacerbations of chronic obstructive pulmonary disease (COPD). However, the role of the common cold virus (human rhinovirus) in the production of symptoms and lower airway inflammation at COPD exacerbation is unknown. Thirty three patients with moderate-to-severe COPD were seen at baseline, when the number of chest infections in the previous year was noted, and acutely at COPD exacerbation. Within 48 h after the onset of the exacerbation and at baseline, nasal aspirates and induced sputum were taken for rhinovirus reverse transcriptase polymerase chain reaction (RT-PCR) analysis and determination of cytokine levels. Symptoms, recorded on diary cards, were noted and forced expiratory volume in one second (FEV1) and forced vital capacity (FVC) measured. At exacerbation, mean FEV1 and FVC fell significantly from baseline (p<0.001). Ten of 43 exacerbations were associated with rhinovirus infection, detected in induced sputum. In four of these, nasopharyngeal samples contained no detectable rhinovirus. All baseline samples were negative for rhinovirus. The simultaneous presence of increased nasal discharge/nasal congestion (in 26 of the 43 exacerbations) and increased sputum (29 exacerbations) was strongly associated with the presence of rhinovirus (odds ratio 6.15; p=0.036). Total symptom scores were greater for rhinovirus as compared to nonrhinovirus exacerbations (p=0.039). Median baseline sputum interleukin-6 levels rose from 90.2 to 140.3 pg x mL(-1) at exacerbation (p=0.005); the change was greater in the presence of rhinovirus infection (p=0.008). Rhinovirus infection can be detected at chronic obstructive pulmonary disease exacerbation. This is associated with elevation of lower airway interleukin-6 levels, which may mediate lower airway symptom expression during chronic obstructive pulmonary disease exacerbations.

Randomized controlled trial of domiciliary noninvasive positive pressure ventilation and physical training in severe chronic obstructive pulmonary disease

The addition of noninvasive positive pressure ventilation (NPPV) to an exercise training (ET) program in severe chronic obstructive pulmonary disease (COPD) may produce greater benefits in exercise tolerance and quality of life than after training alone. Forty-five patients with severe stable COPD-mean (SD) FEV(1) 0.96 (0.31) L, Pa(O(2)) 65.4 (9.07) mm Hg, Pa(CO(2)) 45.6 (7.89) mm Hg-were randomized to domiciliary NPPV + ET (n = 23) or ET alone (n = 22). Exercise capacity and health status were assessed at baseline and after an 8-wk training program. There was a significant improvement in mean shuttle walk test (SWT) in the NPPV + ET group: from 169 (112) to 269 (124) m (p = 0.001), compared with the ET group: 205 (100) to 233 (123) m (p = 0.19); mean difference (95% confidence interval [CI]): 72 (12.9 to 131) m. Repeated measures analysis of variance (ANOVA) showed that the differences between the two groups became evident only in the final 4 wk of the training program with a mean end study difference (95% 1CI) of 65.8 (17.1 to 114) m. There was a significant improvement in the Chronic Respiratory Disease Questionnaire (CRDQ) of mean (SD) 24.0 (17.4) (p = < 0.001) in the NPPV + ET group and 11.8 (15.8) (p = 0.003) points in the ET group; mean difference: 12.3 (1.19 to 23.4). Only the NPPV + ET group demonstrated a significant improvement in arterial oxygenation; mean difference: 3.70 mm Hg (0.37 to 7.27). This study suggests that domiciliary NPPV can be used successfully to augment the effects of rehabilitation in severe COPD.

Acute exacerbations of chronic obstructive pulmonary disease are accompanied by elevations of plasma fibrinogen and serum IL-6 levels

BACKGROUND

Respiratory tract infections may acutely increase risk from coronary heart disease (CHD), though the mechanisms have not been defined. Patients with chronic obstructive pulmonary disease (COPD) are prone to repeated exacerbations that are often associated with respiratory infections. These patients also have increased cardiovascular morbidity and mortality. We hypothesized that transient acute increases in plasma fibrinogen, an independent risk factor for CHD, could occur at COPD exacerbation (mediated through a rise in IL6) and thereby provide a mechanism linking respiratory infection to risk of coronary heart disease.

METHODS

93 COPD patients [mean (SD) age 66.8 (8.1) years] were followed regularly over one year, with daily diary card monitoring of respiratory symptoms and peak expiratory flow rate (PEFR); 67 patients [mean FEV1 1.06 (0.44) l, FVC 2.43 (0.79) l] were seen during 120 exacerbations. At each visit spirometry was measured and blood samples taken for plasma fibrinogen and Interleukin-6 (IL-6) levels.

RESULT

At baseline, the mean (SD) plasma fibrinogen was elevated at 3.9 (0.67) g/l in the 67 patients with exacerbations during the study and the median (IQR) IL-6 at 4.3 (2.4 to 6.8) pg/ml. Plasma fibrinogen increased by 0.36 (0.74) g/l at exacerbation (p <0.001). with IL-6 levels rising by 1.10 (-2.73 to 6.95) pg/ml (p = 0.008). There was a relation between the changes in fibrinogen at exacerbation and IL-6 levels (r = 0.348, p <0.001). Multiple regression revealed significantly greater rises in fibrinogen when exacerbations were associated with purulent sputum (b = 0.34 g/l; p = 0.03), increased cough (b = 0.31 g/l, p = 0.019) and symptomatic colds (b = 0.228; p = 0.024).

CONCLUSIONS

Plasma fibrinogen levels were elevated in stable patients with COPD and may contribute to the increased cardiovascular morbidity and mortality in these patients. COPD exacerbations increased serum IL-6 levels, leading to a rise in plasma fibrinogen. Thus acute rather than chronic infection may have a role in predisposing to coronary heart disease or stroke.

Supplemental oxygen during pulmonary rehabilitation in patients with COPD with exercise hypoxaemia

BACKGROUND

Supplemental oxygen in patients with chronic obstructive pulmonary disease (COPD) and exercise hypoxaemia improves exercise capacity and dyspnoea. However, the benefit of oxygen during pulmonary rehabilitation in these patients is still unknown.

METHODS

Twenty five patients with stable COPD (mean (SD) forced expiratory volume in one second (FEV(1)) 0.76 (0.29) l and 30.0 (9.89)% predicted, arterial oxygen tension (PaO(2)) 8.46 (1.22) kPa, arterial carbon dioxide tension (PaCO(2)) 6.32 (1.01) kPa) and significant arterial desaturation on exercise (82.0 (10.4)%) were entered onto a pulmonary rehabilitation programme. Patients were randomised to train whilst breathing oxygen (OT) (n = 13) or air (AT) (n = 12), both at 4 l/min. Assessments included exercise tolerance and associated dyspnoea using the shuttle walk test (SWT) and Borg dyspnoea score, health status, mood state, and performance during daily activities.

RESULTS

The OT group showed a significant reduction in dyspnoea after rehabilitation compared with the AT group (Borg mean difference -1.46 (95% CI -2.72 to -0.19)) but there were no differences in other outcome measures: SWT difference -23.6 m (95% CI -70.7 to 23.5), Chronic Respiratory Disease Questionnaire 3.67 (95% CI -7.70 to 15.1), Hospital Anxiety and Depression Scale 1. 73 (95% CI -2.32 to 5.78), and London Chest Activity of Daily Living Scale -2.18 (95% CI -7.15 to 2.79). At baseline oxygen significantly improved SWT (mean difference 27.3 m (95% CI 14.7 to 39.8) and dyspnoea (-0.68 (95% CI -1.05 to -0.31)) compared with placebo air.

CONCLUSIONS

This study suggests that supplemental oxygen during training does little to enhance exercise tolerance although there is a small benefit in terms of dyspnoea. Patients with severe disabling dyspnoea may find symptomatic relief with supplemental oxygen.

Development and validation of a standardized measure of activity of daily living in patients with severe COPD: the London Chest Activity of Daily Living scale (LCADL)

Activities of daily living (ADL) may be severely restricted in patients with COPD and assessment requires evaluation of the impact of disability and handicap on daily life. This study is concerned with the development and validation of a standardized 15-item questionnaire to assess routine ADL. Sixty (33 male, 27 female) patients with severe COPD, mean (SD) FEV1 0.91 (0.43) l, median (range) age 70 (50-82) years, completed a 59-item ADL list previously generated by open-ended interview and by literature review. Patients also performed the Shuttle Walk Test (SWT), and completed the St George's Respiratory Questionnaire (SGRQ), the Nottingham Extended Activity of Daily Living Questionnaire (EADL) and the Hospital Anxiety and Depression score (HAD). Criteria for item reduction in the development of The London Chest ADL scale (LCADL) consisted of removal of items where the majority of respondents showed no limitation in the activity (n = 19), where there was no association with perception of global health (n = 9), where an association with age or gender was detected (n = 4), or where items showed poor reliability on test re-test (n = 9). Fifteen items were identified as core activities of daily living. The LCADL was then compared with other measures of health status in these patients. There were good correlations with the SGRQ activity and impact components (p=0.70; P<0.0001) and (p=0.58; P<0.0001), respectively, and EADL (p=0.45; P<0.001), and a moderate correlation with HAD anxiety (p=0.28; P<0.03). There was a significant relationship between the SWT and LCADL (p=0.58; P<0.0001), suggesting a relationship between impaired exercise performance and lower ADL scores. There was evidence of high internal consistency of the questionnaire with Chronbach's alpha of 0.98. These findings suggest that the LCADL scale is a valid tool for the assessment of ADL in patients with severe COPD.

Time course and recovery of exacerbations in patients with chronic obstructive pulmonary disease

Although exacerbations of chronic obstructive pulmonary disease (COPD) are associated with symptomatic and physiological deterioration, little is known of the time course and duration of these changes. We have studied symptoms and lung function changes associated with COPD exacerbations to determine factors affecting recovery from exacerbation. A cohort of 101 patients with moderate to severe COPD (mean FEV(1) 41.9% predicted) were studied over a period of 2.5 yr and regularly followed when stable and during 504 exacerbations. Patients recorded daily morning peak expiratory flow rate (PEFR) and changes in respiratory symptoms on diary cards. A subgroup of 34 patients also recorded daily spirometry. Exacerbations were defined by major symptoms (increased dyspnea, increased sputum purulence, increased sputum volume) and minor symptoms. Before onset of exacerbation there was deterioration in the symptoms of dyspnea, sore throat, cough, and symptoms of a common cold (all p < 0.05), but not lung function. Larger falls in PEFR were associated with symptoms of increased dyspnea (p = 0.014), colds (p = 0.047), or increased wheeze (p = 0.009) at exacerbation. Median recovery times were 6 (interquartile range [IQR] 1 to 14) d for PEFR and 7 (IQR 4 to 14) d for daily total symptom score. Recovery of PEFR to baseline values was complete in only 75.2% of exacerbations at 35 d, whereas in 7.1% of exacerbations at 91 d PEFR recovery had not occurred. In the 404 exacerbations where recovery of PEFR to baseline values was complete at 91 d, increased dyspnea and colds at onset of exacerbation were associated with prolonged recovery times (p < 0.001 in both cases). Symptom changes during exacerbation do not closely reflect those of lung function, but their increase may predict exacerbation, with dyspnea or colds characterizing the more severe. Recovery is incomplete in a significant proportion of COPD exacerbations.

Long-term oxygen therapy vs long-term ventilatory assistance

The use of positive-pressure nasal ventilation in combination with LTOT in stable COPD patients with hypercapnic respiratory failure controls hypoventilation and improves daytime ABGs, sleep, and quality of life. Nasal ventilation in COPD is unlikely to produce benefit unless used with supplemental oxygen therapy at night. The patients who show the greatest reduction in overnight PaCO2 with ventilation are the patients most likely to benefit from long-term ventilatory support. Although there is now evidence for short-term benefit from NPPV in hypercapnic COPD, large multicenter studies with survival, exacerbations, and hospital admissions as the primary end points are required to evaluate longer-term effects of this potentially important intervention.

Relation of sputum inflammatory markers to symptoms and lung function changes in COPD exacerbations

BACKGROUND

Although it is presumed that exacerbations of chronic obstructive pulmonary disease (COPD) are associated with increased airway inflammation, there is little information available on inflammatory markers during an exacerbation and the relationship with severity or time course of recovery. A study was undertaken to investigate the sputum cell and cytokine characteristics of COPD when stable and during an exacerbation.

METHODS

Induced sputum samples from 57 patients with moderate to severe COPD were analysed (44 samples were taken during a stable period and 37 during an exacerbation). The patients recorded daily symptoms on diary cards. Cell counts and sputum levels of interleukin (IL)-6 and IL-8 were measured.

RESULTS

Patients with >/=3 exacerbations/year had higher median stable sputum levels of IL-6 (110 (95% CI 11 to 215) pg/ml) and IL-8 (6694 (95% CI 3120 to 11995) pg/ml) than those with </=2 exacerbations/year (22 (95% CI 12 to 93) and 1628 (95% CI 607 to 4812) pg/ml, respectively). Median IL-6 levels were increased during exacerbations compared with stable conditions. The levels of IL-6 during exacerbations were related to the presence of a cold and to the total cell count and eosinophil and lymphocyte numbers, while IL-8 was positively correlated with all sputum cell counts. Sputum cell counts and cytokine levels during an exacerbation did not predict the size and duration of lung function changes in the exacerbation.

CONCLUSIONS

Patients with more frequent exacerbations have higher baseline sputum cytokine levels, which may predict the frequency of future exacerbations.

Adverse effects of nasal continuous positive airway pressure therapy in sleep apnoea syndrome

Nasal continuous positive airway pressure (nCPAP) is now the treatment of choice for patients with sleep apnoea syndrome. Side-effects and adverse reactions have been described in isolated reports with this device. We have, therefore, systematically studied the side-effects of nCPAP therapy in 300 consecutive patients referred to the London Chest Hospital Ventilatory Support Unit. Ninety-six per cent of patients complained of at least one side-effect resulting from the therapy, with 45 per cent complaining of a side-effect specific to the nasal mask. There was no correlation between the side-effects and level of pressure used during nCPAP. The rate of compliance remained high in spite of the side-effects, with a daily use of 7.8 hours (SD 8.05) and with 83 per cent of the patients using the device every night. Although nCPAP treatment remains acceptable to most patients there exists a high incidence of adverse effects.

Domiciliary oxygen therapy services: clinical guidelines and advice for prescribers. Summary of a report of the Royal College of Physicians

The criteria for the use of long-term oxygen therapy in chronic obstructive pulmonary disease are well established, but there is variability in prescribing habits, poor adherence to guidelines, and lack of organised follow-up and monitoring arrangements. This report gives new guidance on the use of domiciliary oxygen in adult patients with chronic respiratory disease and indications for its use in paediatrics, cardiology and palliative medicine. New methods of prescribing are also recommended.