SLEEP 102

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SLEEP 102

• Tehmina Badar, M.D., F.C.C.P.
• Diplomate, American Board of Sleep Medicine

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What is OSA?

• AHI gt 5 AND symptoms of excessive daytime
  sleepiness, unrefreshing sleep or chronic fatigue

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DEFINITIONS

• Obstructive Apnea-a cessation of airflow-at least
  10 s w/ continued effort to breathe
• Central Apnea-apnea w/ no effort to breathe
• Mixed Apnea-apnea begins as central but towards
  end there is effort to breathe without airflow

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DEFINITIONS

• Hypopnea-variable
• CMS approved-at least a 30 reduction in
  thoracoabdominal movement or airflow as compared
  to baseline lasting at least 10 seconds and with
  gt 4 drop in SpO2
• Or w/ arousal?
• Frequency of apneas and hypopneas per hour of
  sleepapnea-hypopnea index-AHI

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PREVALENCE

• Prevalence of OSA in Western world5-Am J Respir
  Crit Care Med 2002165
• More common-males
• 2-3 x gt females
• Until menopause when prevalence increases
• Am J Respir Crit Care Med 2001 163
• May be more common in African Americans,
  Hispanics-Am J Respir Crit Care Med 1997155
  Sleep 199720

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PREVALENCE

• Increases with age, although severity
  decreases-Sleep Heart Health Study- Arch Intern
  Med 2002162 Am J Respir Crit Care med 1998157

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Signs and Symptoms

• Cardinal symptom-daytime sleepiness
• Sleep fragmentation due to repetitive arousals
• Chronic fatigue or tiredness-? females Ann Intern
  Med 1995122.
• Snoring
• Common
• Frequently disrupts bedpartner
• Witnessed apneic episodes (breathing pauses)

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Signs and Symptoms

• Awakening w/ headache Arch Int Med 1997159.
• Impotence
• Awakening w/ dry throat
• Awakening gasping for air or w/ smothering
  sensation
• Restless sleep
• Memory impairment-often ?aging
• Lower scores on neurocognitive testing Am J Resp
  Crit Care Med 1997156.

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PATHOPHYSIOLOGY

• An imbalance of dilating and collapsing forces on
  upper airway
• Factors that place upper a/w at risk for collapse
  during sleep
• Narrower upper airways (although considerable
  overlap w/ normals)-imaging studies
• Typically because of obesity and/or increased
  Neck circumference-

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PATHOPHYSIOLOGY

• Volumetric MRI studies suggest that volume of
  tongue and lateral pharyngeal walls are increased
  vs controls Am J Respir Crit Care Med 2003 168
• Hypothesized that during wakefulness, this
  narrowed a/w kept open by active pharyngeal
  dilator muscles
• Shown to have higher activity in awake apneics J
  Clin Invest 199289

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PATHOPHYSIOLOGY

• With sleep onset, compensation lost and a/w
  collapses
• Other factors promoting collapse
• Recumbent position
• Lung volume decreases
• Decreases traction on a/w J Appl Physiol 199170
• NM damage of upper airway-may hinder compensatory
  reflexes

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PATHOPHYSIOLOGY

• Inflammation of upper a/w which may promote
  vasodilation and edema Am Rev Respir Dis 1990141
• Abnormal ventilatory control Am J Resp Crit Care
  Med 2001 163
• Once a/w collapses
• Increased vagal tone and bradycardia due to
  hypoxemic effect on carotid body J Clin Invest
  198269

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PATHOPHYSIOLOGY

• Mild pulmonary arterial hypertension Eur Respir J
  199812
• Leading to leftward shift of the interventricular
  septum reducing LVEDV as well as causing
  increased left ventricular afterload Chest
  1991100. N Engl J Med 1979301
• BP initially falls because of drop in HR but then
  progressively rises w/ abrupt elevation when
  arousal occurs Ann Intern Med 197685

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PATHOPHYSIOLOGY

• Cardiac output decreases during apnea then
  increases at its termination Chest 198689. J
  Appl Physiol 199273.
• Altered cerebral blood flow and autoregulation
  occur as well as increased ICP Stroke 199829.
  Chest 198995. Sleep 198710.

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PATHOPHYSIOLOGY

• Reestablishment of patent a/w occurs due to
  arousal from sleep as a result of several stimuli
• Hypoxemia
• Hypercarbia
• Progressively negative intrathoracic pressure
• Am Rev Resp Dis 1990142.

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PATHOPHYSIOLOGY

• Arousal results in establishment of awake upper
  a/w muscle tone, resumption of ventilation until
  sleep resumes allowing a/w to re-collapse and
  cycle repeats

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SEQUELAE

• Cardiovascular
• Systemic HTN
• Pulmonary HTN
• Cardiac arrhythmias
• Transient ischemic attack/stroke
• Metabolic
• Glucose intolerance/diabetes

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SEQUELAE

• Other
• Motor Vehicle Accidents
• Traffic citations
• Neurocognitive impairment

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SEQUELAE

• Association w/ HTN widely studied
• Large epidemiologic studies JAMA 2000283. N Engl
  J Med 2000342.
• Clinic-based studies BMJ 2000320.
• Case control studies Arch Intern Med 2000320.
• All consistently shown that risk of HTN increases
  w/ increasing levels of AHI (even after
  correction for comorbid conditons)
• Obesity
• Age
• gender

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SEQUELAE

• CAD OSA in men/women
• CRP, other inflammatory markers (associated w/
  CAD) increased in OSA, likely due to hypoxic
  stress J Appl Phys 200394. Circulation 2002105.
• Cardiac arrhythmias
• Sinus pauses, 2nd AV Block-most common during
  apneas
• Vtach rare Am J Cardiol 198352.

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SEQUELAE

• Arrhythmias and conduction disturbances usually
  resolve w/ tx of OSA Thorax 19953. Am J Respir
  Crit Care Med 1991151.
• Increased prevalence in CHF w/ prevalence 5-37
  Resp Physiol Neurobiol 2003136
• Diastolic dysfunction seem to be more commonly
  associated w/ OSA Chest 1997111.

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SEQUELAE

• In pts who present to hospital w/ TIA/CVA
  prevalence of OSA very high Neurology 199647.
  Stroke 199627.
• Sleep Heart Health Study-strongest association
  b/w CVA and OSA than any other CV disease Am J
  Respir Crit Care Med 2001163.
• Pts w/ concomitant CVA and OSA have a worse
  functional outcome and higher mortality Stroke
  199627.

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SEQUELAE

• Higher no. of at fault accidents and traffic
  tickets Am J Respir Crit Care Med 1998158. N
  Engl J Med 1999340.
• The worse the OSA, the more accidents. Sleep
  199922.
• Tx w/ CPAP effective in lowering accident rates
  Thorax 200156.

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SEQUELAE

• When evaluating a pt w/ ?OSA, always ask about
  falling asleep while driving
• If had MVAs or near MVAs related to falling
  asleep, should be urged to curtail driving until
  testing completed
• Always document Am J Resp Crit Care Med 1994150.

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TREATMENTS

• Behavioral
• Weight loss
• Avoidance of supine position
• Avoidance of exacerbating substances (e.g. ETOH)
• Devices
• Positive pressure devices
• Oral appliances

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TREATMENTS

• Surgery
• Bariatric surgery for morbidly obese
• Tracheotomy
• UPPP
• Maxillomandibular advancement

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DIAGNOSIS

• Polysomnogram-gold standard
• EEG, EOG, muscle activity
• Various cardiorespiratory parameters
• Airflow
• Respiratory effort
• Oximetry
• ECG

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Who Needs a Sleep Study?

• Practice Parameters for the Indications for
  Polysomnography and Related Procedures An Update
  for 2005 Sleep 2005 284
• A first night psg for all with suspicion of Sleep
  Related Breathing Disorder (SRBD)
• In those w/ strong suspicion of OSA, if other
  causes for symptoms have been excluded, a 2nd
  night of diagnostic PSG m/b necessary

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Who Needs a Sleep Study?

• Polysomnogram indicated for positive airway
  pressure titration in pts w/ SRBD
• RDI of gt15 regardless of symptoms
• RDI of gt5 with excessive daytime sleepiness

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Who Needs a Sleep Study?

• Should you order a split night???
• Diagnostic, therapeutic
• An AHI of at least 40 documented during a minimum
  of 2 hours of diagnostic PSG
• An AHI between 20-40 based on clinical judgment
• Repetitive long obstructions and/or major
  desaturations
• Repetitive dysrhythmias
• At RDI lt 40, CPAP pressure requirements may be
  less accurate vs full night

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Who Needs a Sleep Study?

• CPAP titration (split)
• At least 3 hrs (because respiratory events worsen
  as night progresses)
• Must include REM sleep with pt in supine position
• If does not achieve REM, supine m/ need to order
  full CPAP titration study for most accurate
  pressure

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Who Needs a Sleep Study?

• Those undergoing upper a/w surgery for snoring or
  OSA
• If using oral appliance to ensure therapeutic
  benefit
• After surgical treatment of pts w/ mod-severe OSA
  to ensure satisfactory response

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Who Needs a Sleep Study?

• After substantial weight loss (10) to ascertain
  necessity of CPAP at previously titrated pressure
• After weight gain (10) who are again symptomatic
  despite continued use of CPAP at previous setting
• When clinical response in insufficient or when
  sxs reoccur despite good initial response ?
  Concurrent sleep disorder

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Who Needs a Sleep Study?

• A f/u psg not routinely indicated in pts treated
  w/ CPAP who continue to do well
• Pts w/ systolic or diastolic heart failure if
  they have nocturnal symptoms suggestive of SRBD
• Disturbed sleep
• Nocturnal dyspnea
• Snoring
• Or if remain symptomatic despite optimal medical
  management of CHF

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Who Needs a Sleep Study?

• Pts w/ CAD w/ symptoms of sleep apnea
• Pts w/ hx of CVA or TIA w/ symptoms of sleep
  apnea
• Pts w/ significant tachyarrythmias or
  bradyarrhythmias w/ symptoms

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Preparing the patient

• What I do when ordering a sleep study
• Discuss with patients the importance of sleep
  apnea and its relevance to many diseases
• Explain to them what a sleep study entails
• Leads
• Spending the night
• Sleep tech
• bathroom
• Sleep literature
• Sinus congestion/allergic rhinitis
• Nasal steroid