Restless legs syndrome

Restless legs syndrome (RLS) is a common neurological sensory‐motor disorder that is characterized by intense restlessness and unpleasant creeping sensations deep inside the lower legs. Symptoms appear when the legs are at rest and are worst in the evening and at night. They force patients to keep moving their legs, and often to get out of bed and wander about. Periodic limb movements (PLMS) are also common during sleep amongst those suffering from RLS, and sleep efficiency is severely reduced. There are idiopathic as well as symptomatic forms of RLS, the latter being associated with e.g. pregnancy, iron deficiency and chronic renal failure. A family history of RLS is very common and pedigrees in these cases suggest an autosomal‐dominant transmission with high penetrance. Genetic investigations have been performed in order to identify genes associated with RLS. Several loci have been found (on chromosomes 12q, 14q, 9p, 2q, 20p and 16p). Pathophysiology of RLS remains incompletely understood. However, advanced brain imaging studies and positive results of dopaminergic treatment suggest that RLS may be generated by dopamine dysfunction locally within the central nervous system. At present, there is a wide range of treatment options including levodopa, dopamine agonists, opioids, benzodiazepines, antiepileptic drugs and iron supplements.     

Strategies to augment adherence in the management of sleep‐disordered breathing

Continuous positive airway pressure (CPAP) is highly effective in treating sleep‐disordered breathing (SDB). However, unlike surgical interventions, this treatment modality relies heavily on patient acceptance and adherence. The current definition of adherence is largely arbitrary and is mainly used by third‐party payers to determine CPAP reimbursement but CPAP adherence remains sub‐optimal. Strategies to augment adherence, especially early in the course of a CPAP trial, are needed in the management of SDB. An understanding of the basis for observed differences in CPAP and oral appliance (OA) use is necessary in developing these strategies, but to date no single factor has been consistently identified. Consequently, a multidimensional approach using educational, behavioural, technological and potentially pharmacological strategies to target (i) disease characteristics, (ii) patient characteristics including psychosocial factors, (iii) treatment protocols and (iv) technological devices and side effects that may influence adherence, is likely required to augment the complex behaviour of CPAP and OA use. In the near future, we envision a personalized medicine approach to determine the risk of non‐adherence and set individualized adherence goals aimed at treating specific symptoms (e.g. excessive daytime sleepiness) and reducing the risk of patient‐specific SDB consequences (e.g. atherosclerosis). Resources for interventions to improve adherence such as educational programmes and telemedicine encounters could then be more efficiently allocated.     

Significance of endothelial dysfunction in sleep‐related breathing disorder

The endothelium functions not only as a semi‐selective barrier between body tissue and circulation; it also plays an active role in the maintenance of a healthy vasculature. Endothelial dysfunction is increasingly found to play a pivotal role in the pathogenesis of atherosclerosis. Impaired endothelium‐dependent vasodilation, as a marker of endothelial dysfunction, predates and predicts cardiovascular disease. Endothelial dysfunction is thought to result from oxidative stress, inflammatory gene activation and cytokine cascade, as well as impairment of endothelial repair mechanisms. In the context of sleep‐related breathing disorders, obstructive sleep apnoea (OSA) is postulated to contribute independently to cardiovascular morbidity and mortality. Thus, endothelial dysfunction is an important target of research in vascular pathogenesis and also serves as an intermediary outcome indicator in clinical trials evaluating cardiovascular sequelae in OSA. Basic or translational studies have identified cellular and molecular mechanisms of potential relevance to endothelial dysfunction in OSA, while epidemiological or clinical studies have shown endothelial dysfunction attributable to sleep‐disordered breathing, which could improve with effective treatment of OSA. Endothelial dysfunction is poised to serve as a call for timely intervention with possibility of halting or even reverting vascular injury in sleep‐related breathing disorders. Much remains to be explored about the complex pathways of endothelial dysfunction and its clinical manifestations in subjects with OSA, which are likely to involve multiple contributing factors. Evidence‐based information will allow us to construct the framework for guiding individualized clinical management and public health strategies for OSA, as well as cardiometabolic diseases.     

Dysfunctional breathing treated with continuous positive airway pressure in newly diagnosed obstructive sleep apnoea: a prospective cohort study

A prospective cohort study investigating patients with obstructive sleep apnoea (OSA) was conducted to determine the prevalence of dysfunctional breathing and if continuous positive airway pressure (CPAP) therapy improves associated symptoms. Almost half of newly diagnosed patients with OSA had dysfunctional breathing and CPAP was not an effective treatment. Dysfunctional breathing is common in patients with OSA.     

Anaesthetic management of sleep‐disordered breathing in adults

Anaesthesia and sleep are different states of unconsciousness with considerable physiological common ground. Because of their shared depressant effects on muscle activation and ventilatory drive, patients with anatomically compromised airways will tend to obstruct in either state and those with impaired ventilatory capacity will tend to hypoventilate. Breathing behaviour in one state is predictive of that in the other. An essential difference is that while arousal responses are preserved during sleep, they are depressed during sedation and abolished by anaesthesia. This renders patients with sleep‐related breathing disorders vulnerable to hypoventilation and asphyxia when deeply sedated. Addressing this vulnerability requires a systematic approach to identification of patients and circumstances that magnify this risk, and methods of managing it that seek to reconcile the need for safety with cost‐effective use of resources.     

Treatment of obstructive sleep apnoea in Samoa progressively reduces daytime blood pressure over 6 months

Background and objective:   While recent meta-analyses suggest that OSA elevates daytime blood pressure (BP), most studies have included patients with mild hypertension, so CPAP treatment has only reduced BP by 2–3 mm Hg. To determine the strength of the OSA–BP relationship, this study examined the effect of CPAP in a cohort where severe OSA and under-treated hypertension coexist.
Methods:   Baseline demographic and sleep study data were recorded in 221 consecutive patients referred for sleep studies in Samoa. OSA was treated with CPAP and BP recorded for 6–7 months in 180 patients. A subgroup of 64 patients, representative of the entire group, but with regular follow-up, is also described.
Results:   OSA was diagnosed in 218/221 patients; of those who commenced CPAP, 180 returned for follow-up at least once within 7 months. Following CPAP, BP decreased by 7.1/5.9 mm Hg at 1 month and 12.9/10.5 mm Hg at 6 months ( n  = 180, P  < 0.0001). In the 64 patients with regular follow-up, those with the highest baseline BP had the greatest fall in BP with CPAP; BP in the hypertensive subgroup (32/64) decreased 21.5/13.1 mm Hg at 6 months ( P  < 0.0001).
Conclusions:   Hypertensive OSA patients can exhibit large falls in BP with CPAP at 1 month, with further significant reductions at 3 and 6 months. Overall, the fall in BP was proportional to the initial elevation of the BP with many patients achieving normal BP at 6 months.     

The role of nasal CPAP in obstructive sleep apnoea syndrome due to mandibular hypoplasia

Melnick Needles syndrome (MNS), Treacher Collins syndrome (TCS) and Pierre Robin syndrome (PRS) are congenital abnormalities with characteristic facial appearances that include micrognathia. A 20‐year‐old girl with MNS, a 16‐year‐old boy with TCS and a 12‐year‐old girl with PRS attended the sleep apnoea clinic at our institution at different times. Diagnostic sleep studies were initially performed on all three patients to confirm the diagnosis of obstructive sleep apnoea syndrome (OSAS). They subsequently commenced nasal CPAP (nCPAP) treatment and their progress was followed. A limited sleep study on the patient with MNS demonstrated moderate/severe OSAS with an AHI of 33 events/h. Commencement of nCPAP resulted in symptomatic improvement. Overnight oximetry in the patient with TCS showed repeated desaturation to SpO₂ <90%. Subsequent treatment by nCPAP almost completely abolished the desaturation events. Overnight polysomnography in the patient with PRS demonstrated severe OSAS with an AHI of 49 events/h. After 3 years of nCPAP therapy, this patient requested discontinuation of treatment. Subsequent polysomnography without nCPAP revealed an AHI of <5 events/h. The use of nCPAP in the patients with MNS and TCS resulted in effective control of their sleep abnormalities. Mandibular growth and enlargement of the posterior airway space led to resolution of OSAS in the patient with PRS. There is a definite role for nCPAP therapy in patients with congenital micrognathia and OSAS. The use of nCPAP may obviate the need for more invasive corrective surgery for OSAS and is not necessarily a life‐long requirement.     

Efficacy of the 'tennis ball technique' versus nCPAP in the management of position-dependent obstructive sleep apnoea syndrome

Background and objective:   Avoidance of sleep in the supine position is recommended in the management of position-dependent OSA hypopnoea syndrome (OSAHS). Our aim was to evaluate the efficacy of a thoracic anti-supine band (TASB), designed to mimic the so-called 'tennis ball technique', compared with nasal CPAP (nCPAP).
Methods:   Twenty adults with mild to moderately severe position-dependent OSAHS (mean AHI ± SD) 22.7 ± 12.0/H (range 6.0–51.2); AHI supine, 59.6 ± 27.5/H, were included in a randomized cross-over trial. Portable sleep studies were undertaken at baseline and after 1 month on each treatment. A successful treatment outcome was defined as AHI ≤ 10/H.
Results:   Mean AHI was 12.0 ± 14.5/H with the TASB and 4.9 ± 3.9/H with nCPAP ( P  = 0.02; 95% confidence interval for the difference: −13.1 to −1.0). With the TASB, treatment 'success' was achieved in 13/18 subjects, whereas 'success' was achieved in 16/18 subjects using nCPAP ( P  = 0.004). In the two subjects with baseline AHI < 10/H, AHI remained below 10 for both therapies. The TASB successfully reduced time spent in the supine position. Mean percentage supine sleep time was 6.3 ± 5.9% with the TASB, and 35.4 ± 34.1% with nCPAP ( P  < 0.001). No significant differences in sleep efficiency or subjective responses were observed between treatments.
Conclusions:   Control of body position during sleep using an anti-supine device mimicking the so-called 'tennis ball technique' provides benefit in the management of position-dependent OSAHS in subjects who meet strict inclusion criteria. The overall improvement is, however, less than for nCPAP.     

Otorhinolaryngological aspects of sleep-related breathing disorders

Snoring and obstructive sleep apnoea (OSA) are disorders within a wide spectrum of sleep-related breathing disorders (SRBD). Given the obesity epidemic, these conditions will become increasingly prevalent and continue to serve as a large economic burden. A thorough clinical evaluation and appropriate investigations will allow stratification of patients into appropriate treatment groups. A multidisciplinary team is required to manage these patients. Patient selection is critical in ensuring successful surgical and non-surgical outcomes. A wide range of options are available and further long term prospective studies, with standardised data capture and outcome goals, are required to evaluate the most appropriate techniques and long term success rates.     

Airline policies for passengers with obstructive sleep apnoea who require in‐flight continuous positive airways pressure

Background and objective: The aim of this study was to investigate the current policies of Australian and New Zealand airlines on the use of in‐flight CPAP by passengers with OSA. Methods: A survey was conducted of 53 commercial airlines servicing international routes. Information was obtained from airline call centres and websites. The policies, approval schemes and costs associated with in‐flight use of CPAP were documented for individual airlines. Results: Of the 53 airlines contacted, 28 (53%) were able to support passengers requiring in‐flight CPAP. All these airlines required passengers to bring their own machines, and allowed the use of battery‐operated machines. Six airlines (21%) allowed passengers to plug their machines into the aircraft power supply. The majority of airlines (19, 68%) did not charge passengers for the use of CPAP, while 9 (32%) were unsure of their charging policies. Many airlines only permitted certain models of CPAP machine or battery types. Conclusions: Many airlines are unaware of CPAP. Those who are, have relatively consistent policies concerning the use of in‐flight CPAP.     

Global burden of sleep‐disordered breathing and its implications

One‐seventh of the world's adult population, or approximately one billion people, are estimated to have OSA. Over the past four decades, obesity, the main risk factor for OSA, has risen in striking proportion worldwide. In the past 5 years, the WHO estimates global obesity to affect almost two billion adults. A second major risk factor for OSA is advanced age. As the prevalence of the ageing population and obesity increases, the vulnerability towards having OSA increases. In addition to these traditional OSA risk factors, studies of the global population reveal select contributing features and phenotypes, including extreme phenotypes and symptom clusters that deserve further examination. Untreated OSA is associated with significant comorbidities and mortality. These represent a tremendous threat to the individual and global health. Beyond the personal toll, the economic costs of OSA are far‐reaching, affecting the individual, family and society directly and indirectly, in terms of productivity and public safety. A better understanding of the pathophysiology, individual and ethnic similarities and differences is needed to better facilitate management of this chronic disease. In some countries, measures of the OSA disease burden are sparse. As the global burden of OSA and its associated comorbidities are projected to further increase, the infrastructure to diagnose and manage OSA will need to adapt. The use of novel approaches (electronic health records and artificial intelligence) to stratify risk, diagnose and affect treatment are necessary. Together, a unified multi‐disciplinary, multi‐organizational, global approach will be needed to manage this disease.     

Continuous positive airway pressure is associated with a decrease in pulmonary artery pressure in patients with obstructive sleep apnoea: A meta‐analysis

Pulmonary hypertension has been recognized as being associated with obstructive sleep apnoea (OSA). Continuous positive airway pressure (CPAP) might reduce pulmonary artery pressure in OSA patients; however, evidence from clinical studies is limited and inconsistent. This meta‐analysis aims to assess whether CPAP is associated with a decrease in pulmonary artery pressure in patients with OSA. This systematic review was performed in accordance with the Meta‐analysis of Observational Studies in Epidemiology guidelines. Published studies were identified through a search in MEDLINE, EMBASE and the Cochrane library through to May 2013. Two reviewers sorted papers and extracted data. A random‐effects model was used to combine results across studies comparing pulmonary artery pressure in OSA patients before and after CPAP treatment. Six articles with 181 patients were included in this meta‐analysis, including five before‐after studies and one matched‐control study. The meta‐analysis showed that CPAP was associated with a statistically significant reduction in pulmonary artery pressure in OSA patients (standardized mean difference ?1.34, 95% confidence interval: ?2.33 to ?0.34, P = 0.009). Although this meta‐analysis has some limitations, it indicates that CPAP is associated with a decrease in pulmonary artery pressure in patients with OSA.