Sleep Disordered Breathing Flashcards
Normal Sleep Cycle
There is two main stages of sleep
- Non-Rapid Eye Movement (Non-REM)
- Quiet or slow wave sleep
- Rapid Eye Movement
- Active or dreaming sleep
How are stages of sleep determined
Stages of sleep are determined through electrophysiological monitoring
EEG, EOG, EMG
Different Stages of Sleep
W: wakefulness
N1: non-REM 1
N2: non-REM 2
R: RE
NREM Sleep Sub Stages
N1
N2
N3- Has 2 levels
N1 and N2 are more chaotic whereas N3 is slower and more regular
Cycles of 60-90 minutes
Majority of the time in N2
NREM Sleep
Contributes to physical rest and may bolster the immune system and digestive system
Interruptions in these sleep stages (particularly N3) can interfere with normal growth patterns, healing, and immune response (especially in peds)
REM Sleep
- Signified by an increase in EEG activity
- Lasts 5-40 minutes
- Lengthen as the sleep progresses
- Contributes to psychological rest and long-term emotional and well-being
- May bolster memory
REM Sleep and Sleep Disordered Breathing
Sleep related hypoventilation and apnea are frequent
Reduced response to hypoxia and hypocapnia
Profound atonia (muscle has lost its strength) affecting arms, legs intercostal and upper airway (does not affect diaphragm
Sleep Disordered Breathing
Describes a group of disorder that are characterized through abnormalities of the respiratory pattern (pauses of breathing) or the quantity of ventilation during sleep
Types of Sleep Apnea
Upper airway resistance syndrome (UARS)
Obstructive Sleep Apnea
Central sleep apnea
Mixed Sleep Apnea
Severity Progression From Snoring to Severe OSA
Snoring
Hypopnea
Mild Osa
Severe OSA
Hypopnea
A significant decrease in breathing without a complete cessation of airflow
Both the decreased SpO2 and/or the sleep arousal are the physiological significant features of hypopnea
Upper Airway Resistance Syndrome
Increased airway resistance results in an extra effort to breath
This can cause arousals and increases in blood pressure
Can also reduce arterial oxygenation
10 or more apneas lasting less than 10 seconds per hour
A person may or may not wake up
Sleep Apnea
Defined as the cessation of breathing
OSA requires apneas to be 10 seconds or longer (may exceed 100 seconds) until the brain reacts to overcome the problem
Sleep apnea is diagnosed when there is more than 5 apneas per hour occurring over a 6 hour period
Sleep apneas may appear in all age groups- In infants, it may play a role in SIDS
Individuals with sleep apnea had other chronic conditions. -Ex. Diabetes, hypertension, heart disease, and/or mood disorder
Obstructive Sleep Apnea (OSA)
The most common type of sleep apnea
Obstructive sleep apnea (OSA) is a sleep-related breathing disorder that is characterized by intermittent closure of the upper airway associated with desaturation and arousal from sleep.
Approximately 25% of the Canadian population is at risk of OSA, but only about 5% have been diagnosed.
Caused by a small or unstable pharyngeal airway making them periodically struggling to breath as they are unable to inhale effectively as their airway has collapsed
Obstructive Sleep Apnea (OSA)
Anatomical Causes
- Excess of soft tissue
- Obesity
- Though not all people with OSA are obese and a significant number of adults with normal BMI have a decreased tone causing airway collapse and sleep apnea
- The cause of this is not well understood
- Though not all people with OSA are obese and a significant number of adults with normal BMI have a decreased tone causing airway collapse and sleep apnea
- Tonsillar hypertrophy (enlarged tonsils)
- Mostly in peds
Obstructive Sleep Apnea (OSA)
Neurological Causes
Decreased muscle tone
While awake the pharyngeal tone is maintained through an increased activity of the airway dilator muscle
This is lost during sleep and the narrowing and/or closure of airway results
Obstructive Sleep Apnea (OSA)
Signs and Symptons
When asleep the patient will begin quiet and still which is followed by an increased effort to inhale and often resulting in “snorting”. This will end after an intense struggle
Hallmark symptom is excessive daytime sleepiness
Difficulty staying asleep (insomnia)
Awakening with dry mouth or sore throat
Morning headache
Nausea
Intellectual and personality changes
Depression
Nocturnal enuresis
Sexual impotence
Hypertension
Unexplained cardiac problems
Obstructive Sleep Apnea (OSA)
Signs and Symptons in Severe Cases
Suddenly awaken
Sit upright in bed
Gasp for air
Symptoms of sleep apnea are not always an indication of the severity of the sleep apnea!
What is the common cause of most signs and symptons of OSA
These result from the continued stimulation of the sympathetic drive
Risk Factors for OSA
- Excess weight
- Neck size (16.5cm diameter or larger)
- Hypertension
- Anatomic narrowing of upper airway
- Chronic nasal congestion
- Diabetes
- Family history of sleep apnea
- Smoking or use of alcohol, sedatives, or tranquilizers
- Age
- Older than 65 years of age
- Male sex
- Though in post-menopausal women prevalence approaches men in same age range
- CVD
- DM
- Mental illness
Consequences of Untreated OSA
HTN (50%)
Deterioration in QOL, family life
Job loss
Cardiovascular disease- Heart attacks, Stroke
Diabetes
Neurocognitive and performance deficits
Automotive accidents
People with untreated sleep apnea cost the healthcare system more than 2.5 times more than those without.
“Those with sleep apnea are 15 times more likely to be in a motor vehicle or work related accident due to sleepiness”.
Central Sleep Apnea
What Happends During the Sleep Apnea Period
With each episode of apnea blood oxygen levels will reduce (hypoxia), and sleep is disturbed as the sleeper must wake briefly in order to resume breathing
Because the sleeper will not become fully awake they will normally have no recollection of the awakening
This cycle is repeated throughout the night interfering with normal sleep pattern not allowing the patient to feel rested in the morning
Sleep disturbances and repeated reductions in blood oxygen levels result in excessive daytime sleepiness, reduced quality of life, and impaired cognitive function such as memory loss and poor concentration.
When do apneas occur during sleep
Apneas may occur in either non-REM or REM sleep
Apneas are more frequent and more severe in REM and when in a supine body position
% of Canadian diagnosed with sleep apnea
3% of Canadian adults 18 years and older will be diagnosed with sleep apnea
Out of those diagnosed with sleep apnea 4% reported symptoms and risk factors that are associated with a high risk of having or developing obstructive sleep apnea
Sleep Apnea Diagnosis
Many Canadians were diagnosed with sleep apnea without the benefit of sleep laboratory testing.
In order to be diagnosed with sleep apnea the Canadian Thoracic Society recommends that an individual undergo a polysomnography, but portable home monitoring devices are also sometimes used to test for sleep apnea
A high risk for obstructive sleep apnea is have three or more of the following (Canadian Community Health Survery)
Snoring loud enough to be heard through closed doors
Often feeling tired during the day
Having been observed stopping breathing in their sleep
Diagnosed with high blood pressure
Having a BMI >35
Being over 50
Being male
Central Sleep Apnea
Patients with CSA will display a periodic breathing pattern where they periodically not breath or breathe so shallowly that oxygen intake is ineffectual
Waxing and waning or respiratory pattern
May show Cheyne Stokes breathing pattern
Occurs when respiratory centers of the medulla fail to send signals to the respiratory muscles
Characterized by cessation of airflow at the nose and mouth with absence of diaphragmatic excursions
Cheyne-Stokes Breathing
Cheyne-Stokes is a severe type of periodic breathing that is often associated with CHF
Cheyne-Stokes breathing is shallow/under breathing that will alternate with a deep over breathing
Clinical Disorders Associated with CSA
- Congestive heart failure
- Cheyne-Stokes respiration
- Metabolic alkalosis
- Idiopathic hypoventilation syndrome
- Brain stem neoplasm or infarction
- Bulbar poliomyelitis
- Spinal surgery
- Encephaslitis
- Cervical cordotomy
- Hypothyroidism
- Will result in abnormalities in ventilatory control
Bulbar Poliomyelitis
Infectious disease caused the poliovirus
A severe infection can extend into the brainstem and even into higher brain structures, resulting in polioencephalitis. This can affect breathing, swallowing, and other vital functions.
Bulbar polio leads to weakness of muscles innervated by cranial nerves.
Encephalitis
Encephalitis is an acute inflammation (swelling) of the brain usually resulting from either a viral infection or due to the body’s own immune system mistakenly attacking brain tissue
Cervical Cordotomy
Cordotomy is a surgical procedure that disables selected pain-conducting tracts in the spinal cord, in order to achieve loss of pain and temperature perception.
Mixed Sleep Apnea
Combination of obstructive and central sleep apnea
Usually begins as central sleep apnea, followed by:
Ventilatory efforts without airflow—OSA
Clinically, mixed sleep apnea is usually classified and treated as OSA
Overlap Syndrome
When OSA and COPD co-exist
Worse prognosis
Worse ABG abnormalities than “simple” OSA
STOP BANG Questionaire
High Risk: Answering yes to three for more items
Low Risk: Answering yes to less than three items
- S = Snoring
- T = Tiredness
- O= Observed apneas/gasping
- P = Pressure (as in high BP)
- B = BMI
- A = Age
- N = Neck circumference
- G = Gender
STOP BANG Questionaire
Snoring
Do you snore loud enough to be heard through closed doors or louder than talking
STOP BANG Questionaire
BMI
BMI more than 35 kg/m2 ?
STOP BANG Questionaire
Age
Over 50
STOP BANG Questionaire
Neck Circumference
Neck circumference greater than 40 cm?
STOP BANG Questionaire
Gender
Are you male
Epworth Sleepiness Scale
- Used to measure excessive daytime sleepiness
- Has patient rate how likely they are to fall asleep in different situations
- Validated for OSA
- Scores are added up
- 0-9 is normal
- 10-24 indicates need for expert medical advice
- ≥ 16 indicates possibility of severe sleep apnea or nacolepsy
- Can be repeated after beginning treatment with CPAP to see if symptoms have improved
Who Intreprets Sleep Studies
Both studies read and interpreted by a specialist physician (usually a respirologist).
Level 1 Sleep Study
- Polysomnogram (PSG)
- Done in a hospital or sleep lab
- Diagnoses all sleep disorders
- Able to stage sleep
- Uses 16 channels to gather information:
- SpO2, snoring, airflow, EMG, respiratory effort, limb movement, EOG, ECG, EEG
Polysomnogram (PSG)
Obstructive Sleep Apnea
- There will be a lack of airflow, but the presence of respirtory drive
- There will be a paradoxical efforts of the rib cage and abdomen
- Efforts will continue to increase until arousal and airflow returns
- The arousal is shown on the EEG and results in the airway opening and resumption of airflow
Polysomnogram (PSG)
Obstructive Hypopnea
There is a decrease (not total stop) of airflow at the same time as paradoxical efforts
There will be an increase in efforts until arousal occurs and airflow resumes
The arousal will result in complete airway opening and resumption of airflow
There will be a desaturation but to a lesser degree than OSA
Polysomnogram (PSG)
UARS (Respirtory Effort Related Arousal
There will be no detectable decrease in airflow
Subtle paradoxical efforts are not unusual, but efforts will increase until arousal occurs
No desturataion is associated with the arousal
Polysomnogram (PSG)
Central Sleep Apnea
There is a lack of airflow and a lack of respirtory efforts
There will be and arousal which is followed by a maximal respiratory effort
Desaturations are common
Polysomnogram (PSG)
Mixed Sleep Apnea
There is a lack of airflow and respirtory efforts=Central Componenets
Respiratory Efforts resume without airflow= Obstructive Componenet
Arousal with increased respirtory efforts occur
Desaturations are common
Level 3 Sleep Study (home or bedside)
Uses 6 channels to gather information:
SpO2, snoring, airflow, respiratory effort (optional), body position and heart rate
Apnea-Hypopnea Index (AHI)
- The apnea-hypopnea index is defined as the average number of apneas and hypopneas the patient has per hour of sleep.
- The AHI score provides the following severity categories of sleep apnea:
- Normal— < 5
- Mild—5 to 15
- Moderate—15 to 30
- Severe—> 30
Respiratory Disturbance Index (RDI)
RDI= (#of desats and resats events)/ Total monitoring time (hours)
This is calculated by the SnoreSat
Apnea Hypopne Index Vs. Respirtory Disturbance Index
Like the AHI, an RDI > 15 is considered clinically significant and will be treated!
AHI ≠ RDI.
AHI is calculated from the “gold standard” PSG.
RDI is calculated from the Snore Sat.
Diagnosis of OSA
- Level III device
- Ares
- Apnea risk evaluation system
- Gives RDI and AHI.
- PSG
- Gives an “AHI” score
- The gold standard
- Will detect OSA that the ARES misses
Lifestyle Monification for Treatment of Sleep Disordered Breathing
Weight loss/maintain healthy BMI
Good sleep hygiene
Avoidance of alcohol
Work with physician to change/alter schedule of sedatives
Avoid excessive fatigue
Smoking cessation
Treatment of Sleep Disordered Breathing
Types of Positive Airway Pressure Devices
CPAP
APAP
AVAS/VPAP
BiPAP
Treatment of Sleep Disordered Breathing
Positive Airway Pressure Devices-CPAP
Continuous positive airway pressure
Level determined by repeating sleep study while on CPAP
Pressurized air delivered through mask and tubing; designed to act as a pneumatic airway splint
CPAP usage of 4 hours/night on at least 70% of nights is generally considered the minimum required to see improvement in symptoms and quality of life
Established Outcomes
- Decreased BP and MVA
When to use
- Severe OSA
- Mild-moderate PSA
- Pt preference
Treatment of Sleep Disordered Breathing
Positive Airway Pressure Devices-APAP
Auto-adjusting CPAP, within a set range
Thought to result in a lower failure rate
Special modes (“C-Flex”) may decrease the CPAP level during expiration to ease exhalation; “A-flex” does both inspiration and expiration
Treatment of Sleep Disordered Breathing
Positive Airway Pressure Devices-AVAPS/VPAP
Allows volume-targeting and minimal minute volumes
Often used in when severe OSA or a central component
Treatment of Sleep Disordered Breathing
Positive Airway Pressure Devices-BiPAP
Usually when there is a component of hypoventilation
Treatment of Sleep Disordered Breathing
Oral Appliances
- Tongue retaining device (TRD)
- Holds tongue forward to prevent it from falling back and obstructing the airway
- Mandibular advancement device (MAD)
- Holds the lower jaw forward to maintain an open airway
- Over-the-counter and custom made
- May be used in conjunction with CPAP therapy (and allows reduced CPAP pressures to be used)
- These typically used in treating snoring, UARS, intolerant of CPAP, and mild OSA
Treatment of Sleep Disordered Breathing
Surgery
Nasal surgery (septoplasty, turbinate reduction…)
Tonsillectomy
uvulopalatopharyngoplasty
Genioglossal advancement
Mandibular advancement
Surgical interventions typically use a “phased” approach
Treatment of Sleep Disordered Breathing
Positional Therapy
- Devices used to “encourage” sleeping on the side (as snoring is typically worse when on their back)
- Effective for those with positional SDB (i.e. only when supine)
- Methods:
- Specially designed shirt
- “Tennis ball” technique
- Backpack
Treatment of Sleep Disordered Breathing
Other Treatment Options
- Pharmaceutical
- Area of current research
- Neurostimulation
- New surgery
- For pt that cannot tolerate CPAP
- Implant with a sensor that measures breath which sends a signal to the implant which will move the tongue
Signs and Symptons for CSA vs OSA
The symptoms of central sleep apnea are for the most part the same as those of obstructive sleep apnea.
They include chronic fatigue, daytime sleepiness, morning headaches and restless sleep. But if the cause is a neurological disease
The CSA sufferer may also experience difficulty swallowing, voice changes, and an overall sense of weakness and numbness.
Treatment for patient with suspected nocturnal hypoventilation
Patients with suspected nocturnal hypoventilation should not be started on therapy (including oxygen) outside of a monitored setting.
Such patients are at increased risk of worsening respiratory failure and should be referred for polysomographic titration of PAP therapy.
When Deciding Which Treatment to Use
- Patients with AHI or RDI ≥ 5 with daytime sleepiness or equivalent symptoms (fatigue, poor concentration)
- CPAP or oral appliance therapy
- Patients with severe OSA as defined by AHI or RDI
- CPAP as first line therapy; oral appliance for patients who do not tolerate or refuse CPAP
- Allpatients who are started on therapy should be clinically reassessed within 2-4 weeks to ensure that symptoms have improved and that OSA is adequately treated
