sleep apnea in the elderly by ahmad younes professor of thoracic medicine mansoura faculty of...

Sleep Apnea In The Elderly

BY

AHMAD YOUNES PROFESSOR OF THORACIC MEDICINE

Mansoura Faculty of Medicine

Medical Illness & Medications

Psychiatric & Neurologic

Primary Sleep Disorders

Circadian Changes

Poor Sleep Behaviors

Causes of Disturbed

Sleep in Aging

Sleep Problem

Prevalence of Primary Sleep Disorders

ConditionCondition All AdultsAll Adults ElderlyElderly

• InsomniaInsomnia 10-20% 40-50%

• Sleep ApneaSleep Apnea 1%-25% 24%-40%

• Periodic Limb Movements Periodic Limb Movements 2-5% 30%-45%

• Restless Leg Syndrome Restless Leg Syndrome 2%-15% 12%-30%

• REM Sleep BehaviorREM Sleep Behavior 0.5% 0.5%-2%

Definition of sleep apnea

• Sleep disordered breathing includes

1- Obstructive sleep apnea syndrome (OSAS)

2-Central sleep apnea syndrome (CSAS) and

3- Sleep hypoventilation syndrome .• Obstructive sleep apnea is defined as 5 or more

obstructive respiratory events per hour of sleep accompanied by nocturnal or daytime symptoms, or by 15 or more obstructive respiratory events per hour of sleep without accompanying symptoms.

• Central sleep apnea is defined as 5 or more central respiratory events per hour of sleep.

Respiratory events

• Respiratory events may be apneas (cessation of airflow for at least 10 seconds) or hypopneas (at least 30% or 50% reduction of airflow lasting 10 seconds, associated with a drop in oxyhemoglobin saturation of 4%, 3 % or arousal respectively ). Respiratory effort related arousal exist when there is exist when there is a sequence of breaths that lasts at least a sequence of breaths that lasts at least 10 seconds10 seconds, is characterized by , is characterized by increasing respiratory effort andincreasing respiratory effort and leads to an leads to an arousalarousal from sleep but from sleep but does does not meet the criteria of an apnea or hypopnea not meet the criteria of an apnea or hypopnea

• The apnea–hypopnea index (AHI) is the number of apneas and hypopneas per hour of sleep.

• The respiratory disturbance index (RDI) refers to the number of apneas, hypopneas, and respiratory effort-related arousals per hour of sleep.

• The severity of sleep apnea is generally classified by the AHI. AHI of < 5 is considered to be normal, AHI 5–15 is mild sleep apnea, AHI 16–30 is moderate sleep apnea, and AHI >30 is severe sleep apnea

Obstructive apneaObstructive apnea

Central apneaCentral apnea

Mixed apnea Mixed apnea

Cheyne Stokes breathing-central sleep apnea

Cheyne Stokes breathing-central sleep apnea:

Significance of involuntary sleepiness

• Daytime sleepiness can be assessed subjectively by questionnaires such as the Epworth Sleepiness Scale (ESS) and objectively by investigation in the sleep laboratory such as the Multiple Sleep Latency Test (MSLT).

• Elderly patients with sleep apnea report more sleepiness than elderly subjects without sleep apnea and they report a similar degree of sleepiness as young apneic subjects .

• A complaint of daytime sleepiness in the elderly should not be attributed to normal aging, and should prompt further evaluation for an underlying cause including sleep apnea.

Prevalence of sleep apnea• Although the prevalence of OSA is over 4%, only 1.6% had

such a diagnosis by their physician, and only 0.6% were actually treated for OSA, indicating under-diagnosis and under-recognition of this important disorder .

• In the pediatric population, OSA is estimated to occur in 1–3% of children with a peak age of 2–5 years

• The prevalence of OSA is higher in certain groups, such as those with male gender, genetic factors, hormonal disorders (e.g. hypothyroidism), acromegaly, polycystic ovary syndrome, and specific diseases such as renal failure or diabetes.

• The prevalence of OSA among obese individuals has been reported to exceed 30% and may reach as high as 50–98% in the morbidly obese population .

• The overall prevalence of OSA in the elderly is estimated at roughly 30%

Prevalence of sleep apnea• In a community-based study of subjects aged 30–60 years, 24%

of men and 9% of women had sleep apnea, defined as an AHI ≥5;

• 2% of women and 4% of men had sleep apnea syndrome, defined as an AHI ≥5 accompanied by complaints of daytime sleepiness.

• Elderly have sleep apnea prevalence ranging from 18% to 62%.• The prevalence of sleep apnea increased with advancing age .• The apparent increased prevalence of sleep apnea in the elderly

may be largely due to an increased prevalence of central sleep apnea associated with normal aging ,

Prevalence of sleep apnea• The severity of associated hypoxemia decreased with

advancing age. • Sleep apnea syndrome (defined as an AHI ≥10

accompanied by daytime symptoms) was highest in the middle-aged group.

• This suggests that although sleep apnea is more prevalent in the elderly, it is less likely to be symptomatic and to have physiological consequences such as significant hypoxemia.

• This raises the issue of its clinical relevance and whether the criteria for diagnosis of sleep apnea should be different in the elderly than in middle-aged adults.

Pathogenesis of sleep apnea

• The underlying mechanisms that promote the development of sleep apnea in the elderly can be classified into:

(1) Replication of the patho-physiology of sleep apnea in middle-aged adults

(2) Physiological changes that are uniquely associated with aging; and

(3) Consequences of chronic medical disorders and/or medications.

Pathophysiology of sleep apnea in middle-aged adults

• The predominant cause of obstructive sleep apnea in middle-aged adults is obesity, either through its effects on the pharynx and to a lesser extent on lung volume.

• In the Sleep Heart Health Study the strength of the association between sleep apnea and body weight decreased as age increased.

• Male gender is a strong risk factor for sleep apnea, with males having approximately twice the prevalence of sleep apnea as females. This increased prevalence in males is still seen in the elderly , despite the fact that after menopause the prevalence of sleep apnea increases significantly in women.

Physiological changes that are unique to aging

• The physiological consequences of obstructive apnea are a rise in PaCO2, a fall in PaO2, and an increased ventilatory effort against an occluded airway.

• Ultimately, transient arousals from sleep generally occur, which re-establish airway patency and ventilation.

• The individual subsequently returns to sleep and the cycle repeats throughout the night.

• The principal abnormality in the individual with OSA is an anatomically small pharyngeal airway.

• During wakefulness, the individual compensates for the deficient anatomy via reflexive increases in the activity of upper airway muscles that maintain airway patency.

• With sleep onset, these protective compensatory reflexes are lost and airway collapse occurs.

• Both pharyngeal anatomy and physiology may change with age, resulting in the observed age-related increases in the prevalence of OSA.


• There are conflicting data on how aging affects the upper airway, the diameter of which has been reported to be larger or smaller in older adults compared to control subjects.

• Advancing age is associated with increased pharyngeal collapsibility and increased pharyngeal resistance during sleep , both of which may predispose to the pathogenesis of obstructive sleep apnea and contribute to an increased prevalence of obstructive sleep apnea in the elderly.


• There are a number of underlying pathophysiological variables (anatomy ,upper airway muscle function, and central ventilatory instability) that may be important in determining apnea status.

• In some patients, they may have primarily an anatomical problem, whereas other OSA patients may have primarily a problem with upper airway muscle dysfunction.

• Variety of sleep apnea phenotypes exist whereby a particular variable (or group of variables) increases the risk of (or protects from) the development of OSA.

• These phenotypic clusters are potentially important since therapies targeting the underlying pathogenesis of the condition are likely to be different for each of these subgroups

UAW anatomy

• The upper airway requires stiffness of the soft tissue walls around it and activity of the dilator muscles to maintain patency.

• Any reduction in UAW cross sectional area, change in its length, muscle activity, or a combination of these variables, may lead to vulnerability of the UAW to collapse.

• Many of these characteristics may be affected by aging.• Upper airway dilator muscle and increased lung volume

tend to maintain pharyngeal patency.• A small pharyngeal airway in apnea patients is found

compared to controls, with the smallest airway luminal size generally occurring at the level of the velopharynx in both patients and controls .

UAW anatomy• Through upper airway receptor mechanisms during

wakefulness, there is an increase in the activity of the pharyngeal dilator muscles. However, during sleep, these protective mechanisms fail leading to a fall in activity of the pharyngeal dilator muscles and an increased propensity for loss of upper airway patency.

• Aging may compromise upper airway anatomy, and/or neural control of upper airway muscles either through the CNS or through peripheral upper airway receptor mechanisms.

• Finally increased end expiratory lung volume can promote upper airway patency, although this mechanism could also be compromised with aging.

UAW anatomy

• Sleep apnea patients have increased thickness of the lateral pharyngeal walls .

• This finding is helpful in explaining the reduced lateral diameter of the airway lumen in OSA patients as compared to controls.

• Using acoustic reflection in 60 men and 54 women with an age range of 16–74 years. All upper airway dimensions, except at the oropharyngeal junction, decreased with increasing age in both healthy men and women.

• Another researcher ,Older patients (>63 years) had larger upper airways at all pharyngeal levels than the youngest group of patients (<52 years), using a CT assessment of airway size.

• The studies assessing the effects of age on airway anatomy are too sparse and disparate to draw firm conclusions.

Acoustic reflection

Acoustic Rhinometer

Acoustic Pharyngometer

UAW length• Since cross-sectional UAW is generally greater in men

than women, intrinsic pharyngeal size is an unlikely explanation for the male predisposition to pharyngeal collapse.

• Men had a significantly longer UAW than women, independent of body size, so major independent effect of pharyngeal airway length on upper airway collapsibility.

• As non-rigid tubes become longer they are increasingly prone to collapse (assuming similar tethering); So airway length is a potentially important mechanism responsible for the increased UAW collapsibility.

• A significant positive correlation between RDI and UAW length, which persisted when UAW length was normalized to body height .

UAW length• Airway length may also partially explain the age-

related change in the gender predisposition of OSA in children. While in pre-pubertal children the prevalence of OSA is similar between genders, there is a known male predominance in the post-pubertal population and in adults.

• Pre-pubertal children UAW length was similar between boys and girls, and even shorter in boys when normalized to body height

• The pharyngeal airway became significantly longer in post-pubertal males compared to females (both absolute length and length normalized to body height)

UAW muscle function

• Airway patency depends on both UAW anatomy and function,

• Many diseases such as muscular dystrophy and myopathy result in increased risk of OSA, probably secondary to the loss of protecting effect of the UAW dilators.

• Three groups of muscles have been investigated in the context of the pathogenesis of OSA:

(1) the muscles influencing hyoid bone position (geniohyoid, sternohyoid, etc.);

(2) the muscle of the tongue (genioglossus); and (3) the muscles of the palate (tensor palatini, levator palatini). The activity of many of these muscles is increased inspiration

(“phasic muscles”) thus stiffening and dilating the upper airway thereby counteracting during the collapsing influence of negative airway pressure

Central ventilatory instability• The term loop gain is used to refer to the intrinsic stability or

instability in the ventilatory control system.• A system with high loop gain would be relatively unstable

requiring only a minor perturbation to yielding periodic breathing.

• A system with low loop gain would be intrinsically stable with a regular breathing pattern persisting despite a major perturbation.

• Cyclical oscillations from the central pattern generator in the brainstem could therefore yield upper airway collapse when output to the pharyngeal dilator muscles was at its nadir in an individual who was anatomically predisposed.

• Most studies failed to demonstrate a relationship between the higher susceptibility to OSA seen in men or with aging to this ventilatory control instability .

Central ventilatory instability• Since the prevalence of central sleep apnea appears to be

increased in the elderly, it is possible that factors which promote the development of central apnea may be enhanced by aging. For example, an increased ventilatory response to hypercapnia can promote the development of sleep apnea by destabilizing the chemical control of breathing.

• However, it appears that the ventilatory response to hypercapnia during euoxic wakefulness is not altered by aging. In fact, the sensitivity of the hypercapnic ventilatory response may be reduced during hypoxia in the elderly .

• The change in the ventilatory response to hypercapnia during transition from wakefulness to sleep also influences the development of central sleep apnea.

Central ventilatory instability

• Normally, the hypercapnic ventilatory response is reduced during this transition, which helps to stabilize breathing during sleep. Loss of this stabilizing response during aging could promote the development of central apnea.

• Comparison of loop gain in healthy young and elderly subjects found no significant difference between them . Consequently there is no convincing evidence that aging per se destabilizes the control of breathing and that age-related changes in the control of breathing are responsible for the increased prevalence of sleep apnea in the elderly.

Central ventilatory instability• Termination of the apnea generally requires a transient

arousal from sleep thus activating the upper airway muscles and re-establishing airway patency.

• Without such an arousal, profound hypoxemia and hypercapnia would likely ensue.

• The possible mechanisms leading to arousal, include direct stimulation of peripheral and central chemoreceptors by rising PaCO2 and falling PaO2, afferent CNS input from the lung, chest wall, or upper airway receptors resulting from the increasing ventilatory effort that develops over the course of an apnea, or direct stimulation of the reticular activating system by respiratory neurons activated by the apnea process

• Arousal remains an important mechanism by which apneas are terminated, but at the same time arousals may increase the severity of the sleep disordered breathing by promoting greater ventilatory instability

Chronic medical disorders that are associated with sleep apnea

• The prevalence of chronic medical disorders increases with advancing age and many of them, such as heart failure, stroke and renal failure, are associated with the development of sleep apnea.

• Congestive heart failure over 65 years, 71% of those whose left ventricular ejection fraction was < 40% had sleep apnea, defined as an AHI greater than 10. Forty-three percent of patients had OSA and 28% had Cheyne-Stokes respiration.

• The prevalence of sleep apnea is high in patients who have suffered a stroke; 53% of patients with an acute stroke had sleep apnea, reflected by an AHI >10.

• The prevalence of sleep apnea in end-stage renal disease has been reported to be at least 60% in middle-aged patients.

Clinical presentation of sleep apnea


• Significant proportion of elderly patients may have asymptomatic sleep apnea,

• Elderly patients with sleep apnea can present with typical clinical features such as:

1- Daytime sleepiness.2-Snoring, 3-Choking or gasping respirations, 4-Witnessed apneas, 5-Morning headaches, 6-Hypertension

Clinical presentation of sleep apnea• it is important to recognize that sleep apnea may also be

heralded by atypical symptoms that are unique to this age group.

1- Enuresis may be a consequence of sleep disordered breathing in the elderly , and can be improved with effective treatment of sleep apnea.

2- Nocturnal wandering or confusion may be associated with sleep apnea .

3- Cognitive impairment, measured by Mini-Mental State Examination, delayed verbal recall, and impaired constructional abilities, and even dementia, have all been described in the elderly with sleep apnea.

4- Falls during the day or night-time are associated with sleep disordered breathing ,

5- Ocular conditions associated with OSA eg. glaucoma and non arteritic anterior ischemic optic neuropathy (NAION).


• In the middle-aged population, anthropomorphic features, such as BMI, neck and waist circumference , history of snoring and nocturnal choking, are significantly associated with the AHI and, hence, are considered predictive of sleep apnea .

• One study has demonstrated that these typical anthropomorphic features and symptoms are also predictive of sleep apnea in the elderly.


• At age 40 the odds ratio for a positive association between BMI and AHI was 2.0 , but by age 80 it was 1.3. Neck circumference was no longer a significant predictor of AHI by age 80 and waist-to-hip ratio was no longer significant by age 70.

• This suggests that anthropomorphic features used to predict sleep apnea in middle aged subjects may not be as robust in the elderly.

• In addition, a history of snoring was noted to decrease 1.8-fold from age 50–60 to age 70 and beyond, indicating that typical symptoms of sleep apnea may not be reported as frequently in the elderly.

Diagnosis of sleep apnea

• Comprehensive overnight polysomnography in the sleep laboratory is the gold standard for the diagnosis of sleep disordered breathing .

• Alternative diagnostic testing includes nocturnal cardiopulmonary monitoring (i.e. without sleep monitoring) and polysomnography at home.

• Studies that have evaluated these diagnostic modalities have not included elderly subjects, and consequently we are left to extrapolate from studies on younger subjects.

• Cardiopulmonary monitoring in middle-aged subjects has been found to be as effective as polysomnography in predicting which patients will benefit from continuous positive airway pressure therapy .

Diagnosis of sleep apnea• Comparing cardiopulmonary monitoring with

polysomnography in selected patients with a high probability of OSA found no difference in their outcome measurements, which included AHI on CPAP, daytime sleepiness, quality of life, and CPAP requirement .

• Although these data suggest that cardiopulmonary monitoring may be adequate to diagnose sleep apnea in selected elderly subjects, this needs to be confirmed

Diagnosis of sleep apnea

• This suggestion is supported by the fact that the elderly have some unique factors that may confound the accurate interpretation of limited diagnostic testing. For example, the high proportion of central apnea and increased prevalence of periodic limb movements in the elderly may require monitoring of respiratory effort and leg movements, respectively.

• Some elderly subjects are not capable of setting up a monitoring system at home either because of infirmity and/or lack of family support; in such cases, attended monitoring in a sleep laboratory may be the best option.

Impact of sleep apnea on clinical outcomes

Sleepiness

• Sleep apnea is associated with increased daytime sleepiness in the elderly.

• Severe sleep apnea (AHI ≥30) was associated with daytime sleepiness as measured by the Epworth Sleepiness Scale. Even mild sleep apnea in the elderly, as defined by an AHI ≥5, has been associated with increased daytime sleepiness compared to elderly patients with an AHI <5.

• Treatment of OSA with CPAP can reduce daytime sleepiness as measured by ESS and improve daytime vigilance as measured by driving simulation performance

Neuro-cognitive function

• Neurocognitive function in the elderly may be influenced by multiple factors including age itself.

• Although sleep apnea may contribute to changes in neurocognitive function in the elderly, studies to date have shown conflicting evidence.

• Randomly selected elderly patients showed no difference in neuropsychiatric or medical outcomes in subjects with mild or moderate OSA compared to healthy controls .

• Vigilance testing on community-dwelling elderly volunteers has shown that decreased vigilance is associated with increasing age.


• Other studies have demonstrated decreased performance on the Mini-Mental Status Examination associated with increased daytime sleepiness and the severity of sleep apnea reflected by the RDI.

• Diminished neurocognitive performance associated with sleep apnea in the elderly may be due to intermittent nocturnal hypoxia (executive and psychomotor function) or excessive daytime sleepiness and reduced vigilance as a result of sleep fragmentation (attention and memory) or both

• The impact of sleep apnea on daytime function can be amplified by co-existing sleep disorders such as insomnia .


• Treatment of sleep apnea with CPAP has been shown to improve cognition in the elderly.

• Treatment of sleep apnea with CPAP for 3 months showed greater improvement in attention, psychomotor speed, executive functioning, and non-verbal delayed recall in those who were compliant with CPAP . Therapeutic CPAP also improved steering performance and reaction time to target stimuli in patients with OSA.

Mood

• There is a dose–response relationship in the elderly between OSA and the risk of developing depression

• Whether treatment of sleep apnea improves symptoms of depression in the elderly is unclear.

Hypertension• Obstructive sleep apnea is associated

with hypertension in the elderly.• In a 1-year follow-up of elderly patients,

those with sleep apnea (apnea index ≥5) had higher systolic blood pressure than those without sleep apnea .

• Although CPAP therapy has been found in a recent meta-analysis to significantly improve blood pressure, randomized controlled trials of CPAP therapy to date have not included elderly subjects .

Coronary artery disease

• Sleep apnea has been shown to be modestly associated with cardiovascular disease in the Sleep Heart Health Study .

• Because of its association with hypertension, sleep apnea is felt to play a role in cardiovascular disease risk.

Congestive heart failure• In the Sleep Heart Health Study, which included

elderly subjects, OSA was also associated with an increased risk of congestive heart failure with an odds ratio of 2.38 independent of other known risk factors .

• Congestive heart failure is a significant risk factor for the development of central sleep apnea, and sleep apnea is present in about 30–40% of patients with congestive heart failure .

Stroke

• Severe sleep apnea (AHI ≥30) is associated with an increased risk of stroke in the elderly with an adjusted hazard ratio of 2.52 .

• Intolerance of CPAP in a group of elderly patients with OSA following stroke increased the probability of a new vascular event five-fold (odds ratio 5.09) even after adjusting for other vascular and neurological risk factors .

Mortality

• There is conflicting evidence as to whether sleep apnea increases mortality in the elderly.

• In a 10-year follow up of community-dwelling elderly, subjects with a respiratory disturbance index ≥30 had a shorter survival but sleep apnea was not an independent predictor of death (age and cardiovascular and pulmonary disease were identified as independent predictors) .

• Elderly women with an AHI ≥5 had significantly increased mortality This effect may be amplified by co-morbid disease as suggested by the findings of a long-term follow-up study in which the presence of central sleep apnea was associated with a shortened lifespan in elderly subjects with congestive heart failure

Treatment of sleep apnea

Obstructive sleep apnea

• Conservative measures that are used to treat sleep apnea in younger adults should also be considered in the elderly patient.

• Identification and treatment of any underlying medical disorders that contribute to sleep apnea, such as hypothyroidism and acromegaly, weight reduction, the avoidance of alcohol and sedative/hypnotic medication close to bedtime ,and postural therapy.

• CPAP is the gold standard therapy for OSA and it has been shown to be effective in the elderly .

• Elderly patients generally require lower CPAP levels than weight-matched younger subjects, which probably reflects differences in the compliance of the elderly pharynx.


• Compliance with CPAP therapy in the elderly is correlated with attendance at a CPAP education class and improvement of daytime symptoms. Compliance is negatively correlated with nocturia and benign prostatic hypertrophy.

• Treatment of sleep apnea with CPAP is feasible in the elderly with mild to moderate dementia.

• Continuous positive airway pressure adherence in community dwelling patients with Alzheimer’s disease averaged 4.8 hours/night.

• Depressive symptoms predict lack of compliance in this group

Change in the upper airway of a normal individual after application

of CPAP of 0 cm H2O (A) and CPAP of 15 cm H2O (B).


• Oral appliances can be used as an alternative to CPAP in middle-aged patients with mild OSA , although the use of these appliances may be limited in older patients by poor dentition.

• In the absence of correcting a specific upper airway abnormality, such as enlarged tonsils, uvulo-palato-pharyngo-plasty and laser-assisted uvuloplasty , surgical therapy has a very limited role for the management of sleep apnea in adults. This role is even more limited in the elderly where abnormalities such as enlarged tonsils are a rarity and co-existing medical disorders increase the risk of surgical procedures.

• Pharmacological management of residual daytime sleepiness following CPAP therapy with modafinil has been shown to be beneficial .

Mandibular advancement device

Central sleep apnea

Central sleep apnea

• The specific therapy chosen needs to be individualized for each patient and depends partly upon the underlying cause of sleep apnea.

• Cheyne-Stokes respiration (CSR) can be corrected by improvement of ventricular function in patients with congestive heart failure .

• Alternative therapeutic interventions for central sleep apnea, including CSR, include supplemental oxygen , which is not universally effective, and inhaled carbon dioxide , which has been demonstrated to be effective in the sleep laboratory but is not a feasible long-term option at the present time.

• Short-term use of respiratory stimulants, such as theophylline and acetazolamide, has also been demonstrated to improve CSR in patients with heart failure

Central sleep apnea

• A prospective randomized controlled trial of CPAP in patients under 65 years of age with congestive heart failure and CSR found that CPAP reduced apnea, improved nocturnal oxygenation, the 6-minute walk test, and ejection fraction but did not confer a survival benefit.

• For elderly patients with CSR and heart failure, adaptive servoventilation (ASV) improves AHI and daytime sleepiness .

• In a study of middle-aged and elderly patients with complex sleep apnea (persistent CSA despite CPAP treatment of OSA), Bi-level positive airway pressure with backup rate and ASV improved AHI.

Summary

• Sleep apnea is common in the elderly. • Its multi-factorial etiology results in a more

heterogeneous clinical and polysomnographic presentation than what is characteristically seen in younger adults.

• The elderly present some unique challenges for the diagnosis and treatment of sleep apnea, which may require modification of the diagnostic algorithms that have been established in middle-aged patients.

Summary

• Although there is evidence that untreated sleep apnea has clinical consequences, more research that is specifically directed at this patient population is required to determine its impact on important clinical outcomes and co-morbid disease.

• The need for this direction is likely to grow as the population ages and the associated prevalence of sleep apnea increases.

sleep apnea in the elderly by ahmad younes professor of thoracic medicine mansoura faculty of...

Documents