Subjective daytime sleepiness and daytime function in patients on stable methadone maintenance treatment: possible mechanisms.

Introduction: Subjects using opioids on a chronic basis have been reported to have a high prevalence of abnormal sleep architecture and central sleep apnea (CSA). The severity of CSA is, in part, related to blood opioid concentration. The aim of this study was to investigate subjective daytime sleepiness and daytime function in patients who are on stable methadone maintenance treatment (MMT) and to assess the possible mechanisms involving abnormal sleep architecture, CSA severity, and blood methadone concentration.

Prevalence of sleep disordered breathing in paroxysmal and persistent atrial fibrillation patients with normal left ventricular function.

Aims: Recent studies have suggested an emerging link between sleep apnoea and atrial fibrillation (AF). These studies included patients with reduced left ventricular (LV) function which may cause both AF and sleep disordered breathing (SDB). We examined the prevalence of SDB in a population of patients with AF and normal LV function.

Telephone based asthma management - financial and individual benefits.

Methods: The authors calculated the cost of delivering telephone based asthma management compared to usual care. Self efficacy and quality of life were measured at recruitment, 6 months and 12 months. Participants were invited to comment on their experience of the telephone based intervention.

A pilot study of telephone based asthma management.

Background: Self management programs have been advocated for adults who have recently been admitted to hospital or have recently attended an emergency department because of asthma. A new telephone based approach has already been trialled for the management of a number of other chronic conditions. This study sought to determine the effect of a telephone based asthma management program for adults with asthma.

Sleep-disordered breathing with chronic opioid use.

Chronic opioid use for pain relief or as substitution therapy for illicit drug abuse is prevalent in our societies. In the US, retail distribution of methadone and oxycodone has increased by 824 and 660%, respectively, between 1997 and 2003. Mu-opioids depress respiration and deaths related to illicit and non illicit chronic opioid use are not uncommon.

Association between ventilatory response to hypercapnia and obstructive sleep apnea-hypopnea index in asymptomatic subjects.

The majority of awake ventilatory control studies have shown normal or decreased ventilatory response to hypercapnia (HCVR) in obstructive sleep apnea-hypopnea syndrome (OSAHS) patients. These findings are contrary to experimental studies suggesting increased loop gain and greater breathing instability in OSAHS patients. We have investigated the relationship between central chemoreflex sensitivity tested by HCVR and obstructive sleep apnea/hypopnea index (OSAHI) in asymptomatic subjects.

Opioids, sleep architecture and sleep-disordered breathing.

Opioid use whether acute or chronic, illicit or therapeutic is prevalent in Western societies. Opioid receptors are located in the same nuclei that are active in sleep regulation and opioid peptides are suggested to be involved in the induction and maintenance of the sleep state. mu-Opioids are the most commonly used opioids and are recognized respiratory depressants that cause abnormal awake ventilatory responses to hypercapnia and hypoxia.

Central sleep apnea in stable methadone maintenance treatment patients.

Study Objectives: Methadone, a long-acting mu-opioid agonist, is an effective treatment for heroin addiction. Our previous data show that 6 of 10 methadone maintenance treatment (MMT) patients had central sleep apnea (CSA). This study aims to confirm these results and to investigate the pathogenesis of the CSA.

Ventilatory responses to hypoxia and hypercapnia in stable methadone maintenance treatment patients.

Rationale: Methadone is a long-acting mu-opioid and is an effective treatment for heroin addiction. Opioids depress respiration, and patients receiving methadone maintenance treatment (MMT) have higher mortality than the general population. Few studies have investigated ventilatory responses to both hypercapnia and hypoxia in these patients.

Oral versus intravenous corticosteroids in adults hospitalised with acute asthma.

Background: Systemic corticosteroids are routinely used in the management of acute asthma, however the optimum route of administration for patients requiring hospitalisation is unclear. Intravenous (IV) corticosteroids are used in practice, but they may not offer any advantage over oral corticosteroids.

Aim: To compare the efficacy of oral and IV administration of corticosteroids in the treatment of adults hospitalised with acute asthma.

Cardiorespiratory function in stable methadone maintenance treatment (MMT) patients.

Patients in methadone maintenance programmes (MMT) often smoke tobacco and cannabis and many have ongoing illicit drug use. There is therefore potential for these patients to have abnormal cardiorespiratory function; however, few studies address this in stable MMT patients. We assessed resting cardiorespiratory function on 50 stable MMT patients (25 males, 25 females).

Scoring polysomnography respiratory events: the utility of nasal pressure and oro-nasal thermal sensor recordings.

Objective: To evaluate the clinical utility of nasal cannula/pressure (NP) and oro-nasal thermal sensor (Th) recordings, alone and in combination for scoring respiratory events during routine diagnostic polysomnography (PSG).

Background: The use of Th devices to measure airflow during PSG is not recommended because Th are insensitive to airflow changes other then complete airflow cessation. It has been suggested that NP recording is a better measure of airflow and can also detect increased upper airway resistance during PSG.

The Victorian CPAP program: is there a need for additional education and support?

Background: The Victorian Continuous Positive Airways Pressure (CPAP) Program provides CPAP services to financially disadvantaged individuals with moderate to severe sleep apnoea.

Aims: To evaluate health outcomes in patients referred to the pilot program in order to: (i) assess the magnitude of health benefit from treatment in this highly selected population and (ii) identify patient characteristics or factors related to service provision that may influence outcome.

Methods: We adopted a simple before-after research design.

Measurement variability in sleep disorders medicine: the Victorian experience.

Background: Surveys of laboratories in North America have documented significant diversity in the working definitions used for reporting respiratory events in sleep studies.

Aim: To assess sources of variability in the measurement of sleep-disordered breathing (as defined by the Apnoea-Hypopnoea Index) between sleep laboratories in Victoria, Australia.

Methods: A self-complete written questionnaire was constructed following literature review and interviews with staff at three separate sleep laboratories.

Sleep-disordered breathing in stable methadone programme patients: a pilot study.

Aims: To explore the possibility that stable MMP patients have sleep-disordered breathing (SDB) and abnormal sleep architecture defined by nocturnal sleep stages and sleep efficiency.

Design: Observational.

Setting: Regional Methadone Service and sleep disorders laboratory in a university affiliated hospital.

Necrotizing pulmonary granulomata in a marijuana smoker.

We describe the case of a heavy marijuana and tobacco smoker who presented with progressive exertional dyspnea of 2 months' duration, and bilateral nodular lung infiltrates. Examination of the lung fields was normal, and lung function tests showed mild airflow obstruction with moderately reduced gas transfer. BAL returned green-black fluid consisting predominantly of macrophages laden with carbon pigment.

A fluffy white traveller: imported Coccidiodes immitis infection in an Australian tourist.

Pulmonary coccidioidomycosis is a rare cause of pulmonary nodules and respiratory infection in travellers to endemic areas. An Australian tourist suffered an acute respiratory illness while on holiday in Mexico. She subsequently developed erythema nodosum and was noted to have a left pulmonary nodule on chest X-ray after return to Australia.

The incidence of respiratory tract infection in adults requiring hospitalization for asthma.

Unlabelled: Acute respiratory tract infections (RTI) are known to worsen asthma particularly in children. There are few studies in adults assessing the incidence of RTI in patients hospitalized with acute asthma.

Aim: To document the incidence of RTI in adults hospitalized with acute asthma.

Adult asthma and gastro-oesophageal reflux: the effects of omeprazole therapy on asthma.

Background: Approximately 40-60% of patients with asthma have gastro-oesophageal reflux (GOR) and it has been postulated that this may worsen asthma severity.

Aims: To investigate the effect of the potent gastric acid inhibitor omeprazole 40 mg orally daily on peak expiratory flow rate (PEFR), asthma symptoms and histamine bronchial responsiveness in adult patients with both asthma and GOR.

Methods: This was a double blind, randomised, placebo controlled, crossover study.

Screening Young syndrome patients for CFTR mutations.

Young syndrome is characterized by obstructive azoospermia associated with chronic sinobronchial disease of an infectious nature, but normal sweat-gland and pancreatic function as well as normal nasal potential differences. Congenital bilateral absence of the vas deferens (CBAVD) in some patients arises from mutations within the cystic fibrosis (CF) transmembrane regulator (CFTR) gene. Because of some similarities between Young syndrome, CF, and CBAVD, we evaluated 13 patients with Young syndrome, including screening for more than 30 different mutations within the CFTR gene.

A pseudoepidemic of Mycobacterium chelonae: contamination of a bronchoscope and autocleaner.

Background: At fibreoptic bronchoscopy the potential exists for contamination of bronchoscopes and microbiological specimens. Patients may also be cross infected with acid fast bacilli (AFB). During a five month period, 12 bronchial wash specimens of 65 patients undergoing bronchoscopy, one bronchoscope and an autocleaner, were contaminated with the AFB, Mycobacterium chelonae (MCH).

Intravenous aminophylline confers no benefit in acute asthma treated with intravenous steroids and inhaled bronchodilators.

Background: The role of intravenous aminophylline in acute asthma is unclear despite meta-analysis of many studies comparing aminophylline with other bronchodilator therapies.

Aims: The aim of this study is to determine whether continuous aminophylline infusion confers any benefit in acute severe asthmatics treated with intravenous steroids and inhaled bronchodilators.

Methods: The study was randomised, double-blind and placebo-controlled.

Bronchogenic cyst: a cause of pulmonary artery obstruction and breathlessness.

A young woman presenting with breathlessness and a normal chest roentgenogram was found to have unilateral absent lung perfusion on an isotope scan. This was due to a bronchogenic cyst obstructing the right pulmonary artery. This is a rare cause of unilateral absence of lung perfusion and an unusual mode of presentation of a bronchogenic cyst.