SLEEP APNEA
Definition
1. Syndrome in which
repetitive episodes of cessation of airflow or decreases in airflow occur
during sleep in the presence of continued respiratory effort (obstructive sleep
apnea). Cessation of airflow without respiratory effort is seen in central
sleep apnea. A combination of these two events is seen in mixed apneas.
2. The Apnea/Hypopnea
Index (AHI) is a method of quantifying the severity of the sleep disordered
breathing. It is the sum of all respiratory events occurring over a full night
divided by the total sleep time recorded in hours. An AHI>5/hour is
considered abnormal in most populations, and in the appropriate clinical
setting, defines obstructive sleep apnea syndrome (OSAS).
3. Recent studies have
found an incidence of OSAS of approximately 4% in middle aged US males, and
approximately 2% of females. Children and infants may also be afflicted.
Familial clustering has been reported.
4. Risk factors for
OSAS:
o obesity
o advancing age
o snoring
o sleep deprivation
o ethanol and
sedative/hypnotic medications
o hypothyroidism
o general anesthetics
o certain
antihypertensive agents (methyldopa, propranolol)
o COPD
o ribcage and
neuromuscular abnormalities
o CNS disorders
o nasal obstruction
o tonsillar/adenoidal
hypertrophy
o acromegaly
o micro and
retrognathia
o macroglossia
o lymphoma
o Shy-drager Syndrome
o amyloidosis
o congenital syndromes
Signs and Symptoms
1. manifestations of
above mentioned risk factors
2. excessive daytime
somnolence
3. sleep maintenance
problems
4. abnormal motor
activity during sleep
5. abnormal sleep
positions
6. parasomnias
7. signs differ in
children:
o hyperactivity
o irritability
o developmental delays
o growth retardation
Pathophysiology of Obstructive Apneas
1. Initial pharyngeal
obstruction:
o Usually occurs at
level of velopharynx, may also occur in hypopharynx
o Pharyngeal dilator
muscle hypotonia, especially during REM sleep
o Compromised anatomy
of upper airway
2. Consequences of
occlusion
o Hypoxemia
o Hypercapnia
o Arousal
3. Post-apneic
Ventilation
Complications of OSAS
Cardiopulmonary
- cardiac arrhythmias and
conduction disturbances
- sinus arrhythmia
- second degree or complete
AV Block
- prolonged sinus pauses
- paroxysmal atrial
fibrillation
- ventricular tachycardia
- systemic and pulmonary
hypertension
- SBP > 200mm Hg at
conclusion of obstructive events
- decreased MAP during events
- increased ischemic events
(associated with BP changes and gas exchange abnormalities)
- PCWP increases (may cause
pulmonary edema)
- long term consequences
- pulmonary hypertension
- cor pulmonale
- systemic hypertension
- increased vascular
mortality/death
Neuropsychiatric
- excessive daytime somnolence
- personality changes
- cognitive dysfunction and
memory impairment
- impotence
- depression
Socioeconomic
- loss of productivity
- increased motor vehicle
accidents (7-fold increase over non-apneic controls)
Diagnostic Evaluation of Patients with Suspected OSAS
1. History
o typical sleep-wake
cycle
o quality of sleep
o medication ingestion
o habits (tobacco,
caffeine, alcohol)
o stressors
o exercise
o sleep environment
o associated symptoms
(morning headache, dry mouth, snoring)
o family history of
sleep disorders
2. Physical Examination
o HEENT
o Hypertension
o body habitus
o neck size
o cardiac exam
o mental status
o thyroid abnormalities
o neuropathy
3. Sleep Questionnaire
and Diary
4. Nocturnal
Polysomnography
o ambulatory vs.
laboratory
o AHI
o arousal index
o desaturations
o arrhythmias
reatment
1. Weight Reduction
2. Positional Treatment
3. Correct increased
nasal resistance
4. Dental Appliances
5. Increase Upper Airway
Muscle Tone
o avoid alcohol,
sedatives and hypnotics
o pharmacologic
intervention
o protriptyline
o progesterone
o theophylline
o strychnine/nicotine
o electrical
stimulation
6. Nasal Continuous
Positive Airway Pressure
o standard of care
o titrated pressure
o nasal mask vs.
pillows
o CPAP vs. BiPAP
o "AutoPAP"
or DPAP or VPAP
o Compliance
7. Surgical Correction
of Upper Airway Anatomic Abnormalities
o tracheostomy
o nasal surgery
