Positive pressure therapy

The accuracy and difference of scoring rules and methods to score respiratory event-related leg movements in obstructive sleep apnea patients

OBJECTIVE

To compare manual scoring: 1) to the American Academy of Sleep Medicine (AASM) auto-scoring rules. 2) to the AASM and World Association of Sleep Medicine (WASM) rules, and evaluate the accuracy of the AASM and WASM for respiratory event-related limb movements (RRLM) in diagnostic and continuous positive airway pressure (CPAP) titration polysomnography (PSG).

METHODS

We retrospectively, re-scored diagnostic and CPAP titration PSGs of 16 patients with obstructive sleep apnea (OSA), using manual re-scoring by the AASM (mAASM) and WASM (mWASM) criteria for RRLM, periodic limb movements during sleep (PLMS), and limb movements (LM), which were compared to auto-scoring by the AASM (aAASM).

RESULTS

In diagnostic PSG, significant differences were found in LMs (p < 0.05), RRLM (p = 0.009) and the mean duration of PLMS sequences (p = 0.013). In CPAP titration PSG, there was a significant difference in RRLM (p = 0.008) and PLMS with arousal index (p = 0.036). aAASM underestimated LM and RRLM, especially in severe OSA. Changes in RRLM and PLMS with arousal index between diagnostic and titration PSG were significantly different between aAASM and mAASM, but there was no significant difference between scoring by mAASM and mWASM. The ratio of PLMS and RRLM changes between diagnostic and CPAP titration PSG was 0.257 in mAASM and 0.293 in mWASM.

CONCLUSIONS

In addition to the overestimation of RRLM by mAASM compared to aAASM, mAASM may also be more sensitive than aAASM in detecting RRLM changes in the titration PSG. Despite intuitive differences in the definition of RRLM between AASM and WASM rules, RRLM results between mAASM and mWASM were not significant and about 30% of RRLMs might be scored as PLMS by both scoring rules.

Socioeconomic Inequities in Adherence to Positive Airway Pressure Therapy in Population-Level Analysis

(a) Background: In patients with sleep apnea, poor adherence to positive airway pressure (PAP) therapy has been associated with mortality. Regional studies have suggested that lower socioeconomic status is associated with worse PAP adherence but population-level data is lacking. (b) Methods: De-identified data from a nationally representative database of PAP devices was geo-linked to sociodemographic information. (c) Results: In 170,641 patients, those in the lowest quartile of median household income had lower PAP adherence (4.1 + 2.6 hrs/night; 39.6% adherent by Medicare criteria) than those in neighborhoods with highest quartile median household income (4.5 + 2.5 hrs/night; 47% adherent by Medicare criteria; p < 0.0001). In multivariate regression, individuals in neighborhoods with the highest income quartile were more adherent to PAP therapy than those in the lowest income quartile after adjusting for various confounders (adjusted Odds Ratio (adjOR) 1.18; 95% confidence interval (CI) 1.14, 1.21; p < 0.0001). Over the past decade, PAP adherence improved over time (adjOR 1.96; 95%CI 1.94, 2.01), but health inequities in PAP adherence remained even after the Affordable Care Act was passed. (d) Conclusion: In a nationally representative population, disparities in PAP adherence persist despite Medicaid expansion. Interventions aimed at promoting health equity in sleep apnea need to be undertaken.

Heated Humidification during Nasal Continuous Positive Airway Pressure for Obstructive Sleep Apnea Syndrome: Objective Evaluation of Efficacy with Nasal Peak Inspiratory Flow Measurements

Background

Nasal obstruction is one of the most frequent and sometimes troublesome side effects of nasal continuous positive airway pressure (nCPAP) therapy for obstructive sleep apnea syndrome (OSAS).

Methods

We describe a 60-year-old man with allergic seasonal rhinitis and OSAS, with worsening nasal symptoms 1 week after beginning home nCPAP, making nCPAP use difficult (nasal peak inspiratory flow [nPIF], 80 L/minute [57% of his best]).

Results

No significant improvement was obtained with topical steroids or cold humidification. Heated humidification was then considered, achieving an improvement in mean nPIF and symptom scores. An acceptable compliance with CPAP could be obtained during the heated humidification period (3.9 hours of mean daily use).

Conclusion

In this patient with moderately severe OSAS and allergic rhinitis, monitoring nasal symptoms and nasal PIF objectively showed the benefit of heated humidification to overcome nasal intolerance and increase compliance to nCPAP treatment.

Prevalence, Risk Factors, Outcomes, and Treatment of Obstructive Sleep Apnea in Patients with Cerebrovascular Disease: A Systematic Review

BACKGROUND

Obstructive sleep apnea (OSA) is known to increase the risk of cerebrovascular disease (CVD), and patients with CVD have high incidence of OSA. The study aimed to systematically evaluate the prevalence of OSA in patients with CVD.

MATERIALS AND METHODS

Medline, Embase, Science Citation Index, Wanfang, CNKI, and Wiley Online Library were thoroughly searched to identify relevant studies. Random-effects models were used to calculate the pooled rate estimates. Meta-regression and subgroup analysis were performed to explore potential sources of heterogeneity.

RESULTS

Thirty-seven studies with 3242 patients were analyzed. The prevalence of OSA (apnea hypopnea index [AHI] >10) ranged from 34.5% to 92.3%, the random-effects pooled prevalence was 61.9%. Furthermore, the prevalence of sleep disordered breathing (SDB) with AHI  greater than  5 was 70.4%, with AHI greater than 20 was 39.5%, and with AHI greater than 30 was 30.1%. Only 8.3% of the SDB was primarily central apnea. Seventeen studies reported risk factors for OSA, 6 of which used multivariate analyses to extract risk factors. In univariate meta-regression analysis, male had higher prevalence than female (P = .041). OSA was associated with increased length of hospitalization in 2 studies, and 1 long-term study reported severe sleep apnea was associated with poor functional outcome. Among the 5 studies on treatment, 3 indicated that early treatment with CPAP was effective; the remaining studies did not find benefit from CPAP treatment and reported the CPAP acceptance was poor.

CONCLUSIONS

There is high prevalence of OSA in patients with CVD (61.9%). Therefore, accurate diagnosis and treatment to OSA is very important so as to prevent CVD.

Positive Airway Pressure Therapy for Obstructive Sleep Apnea

Positive airway pressure (PAP) is considered first-line therapy for moderate to severe obstructive sleep apnea and may also be considered for mild obstructive sleep apnea, particularly if it is symptomatic or there are concomitant cardiovascular disorders. Continuous PAP is most commonly used. Other modes, such as bilevel airway pressure, autotitrating positive airway pressure, average volume assured pressure support, and adaptive support ventilation, play important roles in the management of sleep-related breathing disorders. This article outlines the indications, description, and comfort features of each mode. Despite the proven efficacy of PAP in treating obstructive sleep apnea syndrome and its sequelae, adherence to therapy is low. Close follow-up of patients for evaluation of adherence to and effectiveness of treatment is important.

Continuous Positive Airway Pressure for Motion Management in Stereotactic Body Radiation Therapy to the Lung: A Controlled Pilot Study

OBJECTIVE

To determine the effect of continuous positive airway pressure (CPAP) on tumor motion, lung volume, and dose to critical organs in patients receiving stereotactic body radiation therapy (SBRT) for lung tumors.

METHODS AND MATERIALS

After institutional review board approval in December 2013, patients with primary or secondary lung tumors referred for SBRT underwent 4-dimensional computed tomographic simulation twice: with free breathing and with CPAP. Tumor excursion was calculated by subtracting the vector of the greatest dimension of the gross tumor volume (GTV) from the internal target volume (ITV). Volumetric and dosimetric determinations were compared with the Wilcoxon signed-rank test. CPAP was used during treatment if judged beneficial.

RESULTS

CPAP was tolerated well in 10 of the 11 patients enrolled. Ten patients with 18 lesions were evaluated. The use of CPAP decreased tumor excursion by 0.5 ± 0.8 cm, 0.4 ± 0.7 cm, and 0.6 ± 0.8 cm in the superior-inferior, right-left, and anterior-posterior planes, respectively (P ≤ .02). Relative to free breathing, the mean ITV reduction was 27% (95% confidence interval [CI] 16%-39%, P<.001). CPAP significantly augmented lung volume, with a mean absolute increase of 915 ± 432 cm(3) and a relative increase of 32% (95% CI 21%-42%, P=.003), contributing to a 22% relative reduction (95% CI 13%-32%, P=.001) in mean lung dose. The use of CPAP was also associated with a relative reduction in mean heart dose by 29% (95% CI 23%-36%, P=.001).

CONCLUSION

In this pilot study, CPAP significantly reduced lung tumor motion compared with free breathing. The smaller ITV, the planning target volume (PTV), and the increase in total lung volume associated with CPAP contributed to a reduction in lung and heart dose. CPAP was well tolerated, reproducible, and simple to implement in the treatment room and should be evaluated further as a novel strategy for motion management in radiation therapy.

Obstructive sleep apnea and other sleep-related syndromes

Obstructive sleep apnea syndrome (OSAS) is a common disorder characterized by repetitive episodes of breathing cessation due to complete or partial collapse of the upper airway therefore affecting ventilation. It is quite common, with a prevalence of about 2-4%, has a strong genetic component, and creates a proinflammatory state with elevated TNFα and other cytokines. If untreated, OSA can lead to significant neurological problems that include stroke, cognitive decline, depression, headaches, peripheral neuropathy, and nonarteritic ischemic optic neuropathy (NAION). Treatment reverses some of these neurological problems. Treatment includes continuous positive airway pressure and its variants, oral appliances, weight loss, upper airway surgery, and rarely maxillofacial procedures. Other sleep breathing disorders such as hypoventilation, central sleep apnea, complex sleep apnea, and Cheyne-Stokes respiration are less common and are sometimes associated with neuromuscular disorders causing diaphragmatic paralysis, but can also be seen in opiate exposure and severe obesity.

The SomnuSeal Oral Mask Is Reasonably Tolerated by Otherwise CPAP Noncompliant Patients with OSA

Compliance with CPAP is the major limiting factor in treating patients with OSA. The novel SomnuSeal mask is an oral self-adaptable mask located between the teeth and the lips ensuring that there are no air leaks or skin abrasions. Fifty patients with AHI > 20, who failed previous CPAP trials, were asked to sleep with the mask for one month. In all patients, the mask was connected to an AutoPAP machine with a heated humidifier. Efficacy, convenience, and compliance (average usage for 4 or more hours per night) were monitored. Fifty patients (41 m and 9 f, mean age 57 ± 12 years, BMI 33.6 ± 4.9 kg/m(2), and AHI 47 ± 23/h) participated. Eleven were classified as compliant (average mask usage of 26 nights, 4.7 hours per night), five were only partially compliant (average usage of 13 nights, 2.9 hours per night), and 34 could not comply with it. In all patients who slept with it, the efficacy (assessed by residual AHI derived from the CPAP device) was good with an AHI of less than 8/hour. Interestingly, the required optimal pressure decreased from an average of 9.3 cmH2O to 4.6 cmH2O. The SomnuSeal oral interface is effective and may result in converting noncompliant untreated patients with OSA into well-treated ones.

Diagnosis and treatment of sleep disorders: a brief review for clinicians

Sleep disorders encompass a wide spectrum of diseases with significant individual health consequences and high economic costs to society. To facilitate the diagnosis and treatment of sleep disorders, this review provides a framework using the International Classification of Sleep Disorders, Primary and secondary insomnia are differentiated, and pharmacological and nonpharmacological treatments are discussed. Common circadian rhythm disorders are described in conjunction with interventions, including chronotherapy and light therapy. The diagnosis and treatment of restless legs syndrome/periodic limb movement disorder is addressed. Attention is focused on obstructive sleep apnea and upper airway resistance syndrome, and their treatment. The constellation of symptoms and findings in narcolepsy are reviewed together with diagnostic testing and therapy, Parasomnias, including sleep terrors, somnambulism, and rapid eye movement (REM) behavior sleep disorders are described, together with associated laboratory testing results and treatment.

Refill rates of accessories for positive airway pressure therapy as a surrogate measure of long-term adherence

STUDY OBJECTIVES

To identify and validate a surrogate measure of long-term adherence to positive airway pressure (PAP) therapy in patients with obstructive sleep apnea (OSA).

DESIGN

Retrospective cohort study.

SETTING

Academic center.

PARTICIPANTS

220 consecutive patients with OSA.

INTERVENTIONS

N/A.

MEASUREMENTS

In patients with OSA who were receiving PAP therapy (for > 1 year), PAP adherence measured by device-download and defined by Medicare criteria was compared to refill rates for mask and other PAP therapy accessories. First, receiver operating characteristic (ROC) curves were constructed to identify a threshold value of refills per year that discriminated best between PAP adherent and non-adherent patients (derivation set; n = 100). Then the predictive accuracy of the threshold value of refills per year was tested in an additional 120 consecutive patients (validation set).

RESULTS

From the derivation set, ROC curve with good discriminant characteristics (ROC 0.83; 95% confidence intervals [CI], 0.75, 0.91, p < 0.0001) was used to identify a threshold value of refills (0.7 refills/year) for distinguishing PAP adherent and non-adherent patients. Subsequently, when the threshold was applied to the validation set, the likelihood ratio for a positive test (weighted for prevalence) predicting adherence to PAP therapy was 7.3 (95%CI, 3.8, 14), and likelihood ratio for a negative test was 0.6 (95%CI; 0.4, 0.8).

CONCLUSION

Refill rate of PAP accessories exhibited good test characteristics for predicting long-term PAP adherence. Such a surrogate measure based upon insurance claims data can be a powerful epidemiological tool in bioinformatics-aided comparative-effectiveness research and to monitor clinical performance of health systems.

Obstructive sleep apnea and stroke

Obstructive sleep apnea (OSA) and stroke are frequent, multifactorial entities that share risk factors, and for which case-control and cross-sectional studies have shown a strong association. Stroke of respiratory centers can lead to apnea. Snoring preceding stroke, documentation of apneas immediately prior to transient ischemic attacks, the results of autonomic studies, and the circadian pattern of stroke, suggest that untreated OSA can contribute to stroke. Although cohort studies indicate that OSA is a stroke risk factor, controversy surrounds the cost-effectiveness of the screening for and treatment of OSA once stroke has occurred.

[Anaesthetic management of adult patients with obstructive sleep apnea syndrome]

OBJECTIVE

The purpose of this review article is to update the anaesthetic management of adult patients with obstructive sleep apnoea syndrome (OSAS).

DATA SOURCES

All references obtained from the medical database Medline related to OSAS and anaesthesia from 1963 until May 2006 were reviewed. References included original articles, observations, clinical cases, and reviews published in English or in French.

DATA SYNTHESIS

The anaesthetic literature related to OSAS and anaesthesia is poor. Understanding anatomy and pathophysiology is important for an optimal anaesthetic management. Since the diagnosis is unknown in almost 80-90% of these patients, many undergo general or regional anaesthesia every day without recognition of the main dangers associated with the condition. Recognition of these patients, especially in the preanaesthetic assessment, is an essential step to prevent perioperative complications. Patients with OSAS are very sensitive to sedatives, hypnotics and opioids. The use of these drugs must be controlled and monitored. Anticipation of difficult intubation avoids complications during induction of general anaesthesia and the use of nasal CPAP decreases the incidence of respiratory complications in the perioperative period.

CONCLUSION

Further research is needed in this field of anesthesia. Intraoperative difficulties in the control of airway and postoperative cardiac and respiratory complications may happen. The use of nasal CPAP in the perioperative period makes the anaesthetic management easier and safer.

Medical devices for the diagnosis and treatment of obstructive sleep apnea

Obstructive sleep apnea is increasingly being recognized as a serious public health problem, and is characterized by repetitive, complete or partial closure of the upper airway during sleep, resulting in sleep fragmentation and oxygen desaturation. The key symptoms of obstructive sleep apnea are snoring, witnessed apneas, excessive daytime sleepiness and deficits in neurocognitive function, adversely impacting on quality of life. The last 10 years have seen a steady increase in evidence linking obstructive sleep apnea to long-term cardiovascular morbidity, including hypertension, myocardial infarction and stroke, and an increased risk of motor vehicle accidents. The discovery of continuous positive airway pressure treatment, and the resultant recognition of the high prevalence of snoring and obstructive sleep apnea, and their impact on health, has spawned a new and rapidly growing global industry. Whilst diagnostic technologic advancements have evolved relatively rapidly, many questions relating to the use of such devices in clinical practice remain unresolved. Similarly, on the therapeutic front, advances in continuous positive airway pressure technology have broadened the use of such treatment, although compliance remains an important impediment to widespread treatment of this common disorder. This has prompted a search for simpler treatment alternatives, ranging from surgical, medical and dental therapies, although none have matched the efficacy of continuous positive airway pressure. Advances in our understanding of the neurobiology of sleep and respiration herald the prospect of pharmacologic treatment in the longer term.

Magnetic airway implants for the treatment of obstructive sleep apnea syndrome

OBJECTIVE

To evaluate repelling magnetic implants to treat obstructive sleep apnea (OSA) using a canine model.

STUDY DESIGN AND SETTING

Magnetic forces equivalent to effective CPAP were estimated with benchtop studies. An acute canine model was used to simulate pharyngeal collapse. Tolerance, safety, and stability of the implants were evaluated in a chronic series of 10 dogs observed over 6 months.

RESULTS

Equivalence to CPAP (10-12 cm H(2)O) was achieved with low-force (<10 g/cm length), light (approximately 2 gram) implants. Magnetic implants prevented airway collapse in the acute canine. Normal behavior, swallowing, and oral intake were noted in the chronic canine over 6 months. Implant extrusion was 10%. Histology showed fibrous encapsulation without chronic inflammation.

CONCLUSIONS

Repelling magnets successfully maintained a patent airway and were well tolerated in the canine.

SIGNIFICANCE

Repelling magnets could represent an implantable alternative to CPAP if human studies reveal similar findings.

CPAP compliance in sleep apnea patients with and without laboratory CPAP titration

Advances in auto-adjusting positive airway pressure technology for obstructive sleep apnea now permit this treatment to be initiated outside of the sleep laboratory environment, bypassing the need for laboratory-based titration studies. Thus far, little research has addressed how such developments may affect compliance to continuous positive airway pressure (CPAP). We tested the effect of laboratory CPAP exposure and technologist support in a retrospective chart review of 98 veterans with obstructive sleep apnea to determine whether patients who received standard laboratory CPAP titration complied better with CPAP than did patients who received no laboratory CPAP titration. Fifty patients underwent standard technician-attended polysomnography (PSG) with CPAP titration, and 48 patients underwent unattended PSG with no laboratory trial of CPAP (first CPAP exposure was at home). Objective CPAP compliance measures were obtained from CPAP units at follow-up visits. Attended-PSG patients wore CPAP significantly longer per night on average (5.0 hours vs 3.9 hours) and tended to wear CPAP on more nights (76.5% vs 64.2%) compared with unattended-PSG patients. These findings suggest that patients' sleep laboratory experience with CPAP and the support and education provided by sleep technologists are important factors in facilitating CPAP compliance.

Sleep apnoea in the older adult : pathophysiology, epidemiology, consequences and management

Sleep apnoea is a breathing disorder in sleep usually caused by repetitive upper airway obstruction. Its primary symptoms include snoring, daytime sleepiness and decreased cognitive functioning. Risk factors for the condition include obesity, anatomical abnormalities, aging, and family history. It has been associated with hypertension, cardiovascular and pulmonary diseases and increased mortality. The prevalence of sleep apnoea increases with age, although the severity of the disorder, as well as the morbidity and mortality associated with it, may actually decrease in the elderly. A decline in cognitive functioning in older adults with sleep apnoea may resemble dementia. Medical management of sleep apnoea rarely relies on drug treatment, as the few drugs (antidepressants and respiratory stimulants) tested for treatment have been found to be ineffective, or cause tolerance or serious adverse effects and complications. The treatment of choice for sleep apnoea is continuous positive airway pressure, a device which generates positive air pressure through a nose mask, creating a splint which keeps the airway unobstructed throughout the night. Weight loss significantly decreases or eliminates apnoeas. Oral appliances are used to enlarge the airway at night by moving the tongue and mandible forward. Positional therapy involves avoiding the supine position during sleep in patients who mostly have apnoeas while lying on their back. Surgical management may also be considered, although with great caution in the elderly, because of their increased risk of complications related to surgery. Surgical procedures include nasal reconstruction, somnoplasty, laser-assisted uvuloplasty, uvulopalatopharyngoplasty, genioglossus advancement and hyoid myotomy, and maxillomandibular advancement for severe cases when other treatments have failed. As a last option, tracheostomy may be performed.

Severe upper airway obstruction during sleep

Few disorders may manifest with predominantly sleep-related obstructive breathing. Obstructive sleep apnea (OSA) is a common disorder, varies in severity and is associated with significant cardiovascular and neurocognitive morbidity. It is estimated that between 8 and 18 million people in the United States have at least mild OSA. Although the exact mechanism of OSA is not well-delineated, multiple factors contribute to the development of upper airway obstruction and include anatomic, mechanical, neurologic, and inflammatory changes in the pharynx. OSA may occur concomitantly with asthma. Approximately 74% of asthmatics experience nocturnal symptoms of airflow obstruction secondary to reactive airways disease. Similar cytokine, chemokine, and histologic changes are seen in both disorders. Sleep deprivation, chronic upper airway edema, and inflammation associated with OSA may further exacerbate nocturnal asthma symptoms. Allergic rhinitis may contribute to both OSA and asthma. Continuous positive airway pressure (CPAP) is the gold standard treatment for OSA. Treatment with CPAP therapy has also been shown to improve both daytime and nighttime peak expiratory flow rates in patients with concomitant OSA and asthma. It is important for allergists to be aware of how OSA may complicate diagnosis and treatment of asthma and allergic rhinitis. A thorough sleep history and high clinical suspicion for OSA is indicated, particularly in asthma patients who are refractory to standard medication treatments.

Continuous positive airway pressure: new generations

Automatic positive airway pressure devices are the most technologically advanced positive airway pressure devices available for use in OSA. Although heterogeneous, they have in common the ability to detect and respond to changes in upper airway resistance. Data cannot necessarily be extrapolated from one device to another, and the field is rapidly advancing. Most studies of APAP have been performed in a supervised setting, or patients have been carefully selected to have a high likelihood of OSA uncomplicated by disorders such as alveolar hypoventilation or central apnea or technical problems such as mask leaks. Studies of APAP for the diagnosis of OSA have shown that APAP can diagnose severe OSA effectively, but the diagnosis of mild-moderate OSA is less reliable. APAP devices also can be effective therapy for selected patients with OSA, with overall similar results to conventional fixed CPAP in terms of respiratory disturbances, sleep quality, nocturnal oxygenation, and daytime sleepiness and performance, with less known or other long-term outcomes. In most studies, mean treatment pressures are lower, without change in side effect profile. Compliance and preference with APAP are similar to or somewhat better than CPAP in most studies. APAP also can be used in an attended setting to titrate an effective pressure for use in long-term conventional CPAP therapy, also with similar results to CPAP in many patients. APAP devices are more expensive than CPAP devices, but the cost may be outweighed if a group of patients who can be diagnosed, treated, or titrated safely in the unattended setting can be identified. Although diagnostic and therapeutic algorithms for APAP have been proposed, the best candidates for this modality must be defined better.

Indications for treatment of obstructive sleep apnea in adults

Obstructive sleep apnea is associated with significant daytime sleepiness, reduced quality of life, insulin resistance, motor vehicle crashes, vascular morbidity and mortality. Current evidence supports the belief that all these parameters can be impacted favorably by treatment. Medical therapy with positive pressure eliminates snoring and favorably affects daytime sleepiness, driving risk, vascular function, vascular risk, and quality of life. Treatment may be difficult to accept or adhere to, and some treatment options are not uniformly effective. The long-term impact of treatment is uncertain.

Compliance with continuous positive airway pressure therapy: assessing and improving treatment outcomes

Although nasal continuous positive airway pressure (CPAP) is generally effective in correcting sleep-related respiratory disturbance and associated daytime sequelae in obstructive sleep apnea syndrome (OSAS), resistance to and intolerance of CPAP poses a serious limitation to its use. Failure to comply with treatment has been reported to be as high as 25 to 50%, with patients typically abandoning therapy during the first 2 to 4 weeks of treatment. Reasons for discontinuing CPAP therapy have been primarily related to issues of mask discomfort, nasal dryness and congestion, and difficulty adapting to the pressure. Although there has been great variability in the reported rates of CPAP compliance, there have been few systematic studies to evaluate barriers to CPAP compliance or ways to improve compliance. Early identification of CPAP-related tolerance problems or barriers, psychological factors, and the predictive value of pretreatment background variables ( ie, age and gender) may enhance compliance with therapy. An important goal for OSAS management is the development of intervention strategies and educational approaches that minimize side effects and maximize patient compliance. A new classification is presented, along with suggestions and ideas for intervention.

Pulmonary complications of obesity

Obesity can profoundly alter pulmonary function and diminish exercise capacity by its adverse effects on respiratory mechanics, resistance within the respiratory system, respiratory muscle function, lung volumes, work and energy cost of breathing, control of breathing, and gas exchange. Weight loss can reverse many of the alterations of pulmonary function produced by obesity. Obesity places the patient at risk of aspiration pneumonia, pulmonary thromboembolism, and respiratory failure. It is the most common precipitating factor for obstructive sleep apnea and is a requirement for the obesity hypoventilation syndrome, both of which are associated with substantial morbidity and increased mortality. There are numerous medical and surgical therapies for obstructive sleep apnea and obesity hypoventilation. Weight reduction in the obese is among the most effective of these measures.

The art and science of continuous positive airway pressure therapy in obstructive sleep apnea

Despite the high prevalence of obstructive sleep apnea (OSA) syndrome, no ideal therapy has emerged to date. Based on recent randomized trials, continuous positive airway pressure (CPAP) therapy is the treatment of choice. Although CPAP can prevent pharyngeal collapse in virtually all patients who choose to wear it, poor patient adherence with treatment limits its effectiveness. Although convincing data exist that treatment with CPAP can alleviate the neurocognitive sequelae of OSA, data on cardiovascular complications are more limited. Several recent reports support a lowering of nocturnal and daytime blood pressure with CPAP, but data on the prevention of myocardial infarction and cerebrovascular events are currently lacking. Patient adherence with CPAP can be improved with optimization of mask comfort, heated humidification, and intensive support and education. For those who remain poorly compliant, alternative therapies such as autotitrating devices and oral positive airway pressure can be considered. Further research into the basic mechanisms underlying OSA will be required for new therapeutic targets to develop.

Compliance with CPAP in elderly patients with OSA

Background: Obstructive sleep apnea (OSA) is common in the general population and especially in the geriatric age group. Nasal continuous positive airway pressure (CPAP) is a highly effective treatment but can be difficult for some patients to use.Objective: We investigated the question if older patients were less compliant with CPAP therapy than younger patients and may not realize its benefits.Methods: We conducted a prospective, non-randomized study comparing use of CPAP in patients over age 65 with patients under age 65. One hundred and seven consecutive patients with a new diagnosis of obstructive sleep apnea were started on therapy with nasal CPAP. We obtained follow-up data on all 107 patients. Compliance with CPAP was assessed by patients subjective report of use and, in a subset of 21 patients, by objective measurement using a microchip installed in the CPAP unit that measures actual hours of use at therapeutic pressure.Results: The percentage of patients using CPAP regularly was not different in the two groups: 70% of patients in the over age 65 group used CPAP regularly vs. 72% of patients under age 65. The over 65 group used CPAP 6.5 nights per week, an average of 6.5 h of use per night. The under 65 group was not significantly different, using CPAP 6.8 nights per week, a mean of 6.7 h of use per night.Conclusion: Patients over age 65 are able to tolerate CPAP as well as patients under age 65.

What is causing excessive daytime sleepiness? Evaluation to distinguish sleep deprivation from sleep disorders

Many people have a temporary spell, often in early afternoon, when they feel drowsy. This passing desire for a quick nap is completely different from excessive daytime sleepiness, which is a much more significant problem. Considering the potentially dire personal and economic consequences of falling asleep unintentionally or at inappropriate times, excessive daytime sleepiness must be taken very seriously. A thorough evaluation, as described by Dr. Mahowald, virtually always leads to a specific underlying cause, allowing effective treatment recommendations.

Reversal of sleep apnea hypopnea syndrome in end-stage renal disease after kidney transplantation

Sleep apnea hypopnea syndrome (SAHS) is extremely common in patients with end-stage renal disease (ESRD). Although the underlying mechanisms linking these 2 conditions remain to be better defined, it is likely that multiple factors are involved. We report an individual with ESRD with severe SAHS that resolved after kidney transplantation. The improvement in SAHS paralleling the effective treatment of ESRD suggests the pathogenesis involves an unstable breathing pattern, possibly caused by an altered metabolic state, uremia, and changes in volume status. The possibility that elevations in cytokine levels could be involved also is discussed and deserves further attention.

Noninvasive ventilation

Noninvasive ventilation refers to the delivery of assisted ventilatory support without the use of an endotracheal tube. Noninvasive positive pressure ventilation (NPPV) can be delivered by using a volume-controlled ventilator, a pressure-controlled ventilator, a bilevel positive airway pressure ventilator, or a continuous positive airway pressure device. During the past decade, there has been a resurgence in the use of noninvasive ventilation, fueled by advances in technology and clinical trials evaluating its use. Several manufacturers produce portable devices that are simple to operate. This review describes the equipment, techniques, and complications associated with NPPV and also the indications for both short-term and long-term applications. NPPV clearly represents an important addition to the techniques available to manage patients with respiratory failure. Future clinical trials evaluating its many clinical applications will help to define populations of patients most apt to benefit from this type of treatment.

Medical-legal aspects of sleep medicine

Sleepiness and sleep disorders are increasingly raising interesting and important medical-legal issues in three areas: violent or injurious behavior arising from the sleep period, accidents or errors in judgment caused by sleepiness behind the wheel or in the workplace, and disability determinations caused by sleepiness-induced work impairment. Sleep-related violence may be caused by many conditions, most of which are diagnosable and treatable. Legal issues raised by these behaviors are usually enigmatic. The nature of such behaviors may be extremely complex, and documenting that a given violent act was caused by such a behavior, after the fact, may be difficult. Guidelines for the medical-legal evaluation of such behaviors have been developed and are evolving. Culpability determination in sleepiness-related industrial or motor vehicle accidents is in the developmental stage, and varies by jurisdiction. Disability determination for workplace sleepiness caused by sleep disorders is in its infancy, and poses a challenge, given the erroneous but pervasive societal attitude that sleepiness is a manifestation of laziness, depression, sloth, work-avoidance behavior, or a defect of character.

Medical management of obstructive sleep apnea

The last 20 years have seen remarkable gains in our understanding of the pathophysiology of sleep-disordered breathing. The rapid growth in both scientific and clinical knowledge has been fueled by the development of nonsurgical therapies for obstructive sleep apnea (OSA). These medical therapies have provided the avenue for public acceptance of the diagnosis and treatment of this common medical condition. However, medical therapy requires active patient participation, to achieve the desired outcomes of improved sleep continuity, daytime functioning, and quality of life. Conservative therapies, such as weight loss and patient positioning; and pharmacological therapies, have been disappointing. Positive pressure therapy has become the treatment of choice for the vast majority of OSA patients. Oral appliances offer an acceptable treatment alternative for select patients. Present research indicates that these mechanical approaches can produce significant decreases in the frequency and severity of sleep-disordered breathing and nocturnal oxyhemoglobin desaturation. Preliminary data from ongoing studies suggest that these interventions will reduce long-term morbidity and possibly mortality.

Indications for positive airway pressure treatment of adult obstructive sleep apnea patients: a consensus statement

We developed a short-length document that clearly delineates a prudent approach to and criteria for reimbursement of positive airway pressure (PAP) costs for the treatment of obstructive sleep apnea (OSA). Treatment modalities for OSA with PAP include continuous positive airway pressure, bilevel or variable PAP, and autotitrating PAP. This guidance on the appropriate criteria for PAP use in OSA is based on widely acknowledged peer-reviewed studies and widely accepted clinical practice. These criteria reflect current opinion on the appropriate clinical management of OSA in lieu of data pending from the Sleep Heart Health Study and upcoming outcome studies. This document is not intended to provide a complete review and analysis of the OSA clinical literature. The key to the success of this document is to foster consensus within and outside the clinical sleep community by providing a common sense and easily understood approach to the treatment of OSA with PAP.