Sleep Apnea Overview and Management

Sleep Apnea

Chapter 32

Page 472

Can Sleep Apnea Go Away?

Sleep apnea is a chronic condition that results from anatomical factors and therefore does not resolve on its own.

Treatment Options

Treatments include:
  - Treating allergies
  - Jaw surgery
  - Circular breathing techniques
  - Weight loss
  - Continuous Positive Airway Pressure (CPAP) therapy

Normal Sleep Stages

Individuals cycle through two major sleep stages during normal sleep:
  - Non-Rapid Eye Movement (Non-REM) Sleep:
    - Also known as quiet or slow-wave sleep.
  - Rapid Eye Movement (REM) Sleep:
    - Also known as active or dreaming sleep.

Electroencephalographic Patterns in Sleep Stages

Characteristic Patterns:

Each stage of sleep is associated with unique electroencephalographic (EEG), behavioral, and breathing patterns:
  - Stage W: (Eyes open – wake)
    - Beta waves
  - Drowsy: (Eyes closed – wake)
    - Alpha waves
  - Non-REM Sleep:
    - Stage N1: (Light sleep)
      - Theta waves
    - Stage N2: (Light sleep)
      - K complexes, vertex waves
    - Stage N3: (Slow wave sleep)
      - Delta waves
    - Stage N3: (Deep sleep)
      - Delta waves
  - REM Sleep:
    - Sawtooth waves

Non-REM Sleep Characteristics

Non-REM sleep generally starts immediately when an individual falls asleep and comprises four distinct stages progressing into deeper sleep:
  - N1 and N2 Stages:
    - Ventilatory rate and tidal volume fluctuate, with brief periods of apnea noted.
  - N3 Stage:
    - Ventilation becomes slow and regular.
EEG during non-REM sleep reveals increased slow-wave activity and loss of alpha rhythm.
- Cheyne-Stokes respiration may be common in older males during non-REM sleep, especially in high-altitude environments.
Non-REM sleep typically lasts from 60 to 90 minutes per cycle.

REM Sleep Characteristics

REM sleep features rapid bursts of alpha rhythms on the EEG and rapid, shallow ventilatory patterns.
Sleep-related hypoventilation and apnea commonly occur during this stage, with normal adults experiencing apneic episodes up to five times per hour.
Apneas can last between 15 to 20 seconds without apparent effects.
- Infants may experience shorter apneas, around 10 seconds, which could still be concerning.
- There is also a marked reduction in hypoxic and hypercapnic ventilatory responses.
The heart rate becomes irregular, and the eyes move rapidly during REM sleep.
Dreaming occurs mainly in REM sleep and is accompanied by profound atonia (muscle paralysis) affecting:
  - Arms
  - Legs
  - Intercostal muscles
  - Upper airway muscles
  - Diaphragm remains active
REM sleep makes up about 20% to 25% of total sleep time.

Types of Sleep Apnea

Apnea Definition:
- Defined as cessation of breathing for a duration of 10 seconds or more.
- Diagnosis of sleep apnea occurs if a patient has more than 5 episodes per hour over a 6-hour period, with episodes occurring in either non-REM or REM sleep.
Apneic episodes are typically more frequent and severe during REM sleep and in the supine position.

Episodes of Apnea

Apneas may last longer than 10 seconds, with severe cases exceeding 100 seconds per episode.
Patients with severe sleep apnea may experience over 500 episodes of apnea each night.
Sleep apnea can affect all age groups, and in infants, it contributes to sudden infant death syndrome (SIDS).

3 Types of Sleep Apnea

Obstructive Sleep Apnea (OSA)
Central Sleep Apnea (CSA)
Mixed Sleep Apnea
Sleep-Related Hypoventilation/Hypoxemia Syndromes

OSA is the most common type of sleep apnea.

Obstructive Sleep Apnea (OSA)

OSA is caused by an anatomic obstruction of the upper airway while ventilatory efforts continue.
During obstruction, patients may appear quiet, holding their breath, followed by desperate inhalation efforts.
- A distinctive sound called "fricative breathing" may be heard at the end of apneic periods.
In severe cases, patients may suddenly awaken, sit upright, and gasp for air, a phenomenon referred to as confusional arousals.
While awake, patients with OSA exhibit normal and regular breathing patterns.
Many OSA patients showcase symptoms akin to the Pickwickian syndrome, based on a character from Charles Dickens, Joe, "the fat boy," who displayed excessive daytime sleepiness and snoring features characteristic of the sleep apnea syndrome.
- Notably, many patients with sleep apnea are not obese.

Risk Factors for OSA

Significant risk factors include:
  - Excessive weight
  - Neck size
  - Hypertension
  - Anatomical narrowing of the upper airway
  - Chronic nasal congestion
  - Diabetes
  - Male sex
  - Age over 65 years
  - Age under 35 years with Black, Hispanic, or Pacific Islander heritage
  - Menopause
  - Family history of sleep apnea
  - Use of alcohol, sedatives, or tranquilizers
  - Smoking

Signs and Symptoms of OSA

Symptoms may include:
  - Loud snoring
  - Observed episodes of breath cessation during sleep
  - Abrupt awakenings with shortness of breath
  - Insomnia
  - Awakening with a dry mouth or sore throat
  - Morning headaches
  - Excessive daytime sleepiness (hypersomnia)
Mallampati Classification Score for Upper Airway Anatomy:
  - Class 1: Soft palate, fauces, uvula, pillars visible
  - Class 2: Soft palate, fauces, some of the uvula visible
  - Class 3: Soft palate and base of the uvula visible
  - Class 4: Only the hard palate visible

Central Sleep Apnea (CSA)

CSA occurs when respiratory centers in the medulla fail to send signals to respiratory muscles, resulting in:
- Cessation of airflow at the nose and mouth
- Cessation of inspiratory efforts (i.e., lack of diaphragmatic movement)
Distinct from OSA, CSA lacks marked inspiratory efforts during apneic periods.
CSA is associated with various cardiovascular, metabolic, and central nervous system disorders.
- Diagnosis requires excessive apnea or hypopnea episodes (more than 30 in a 6-hour period).

Clinical Disorders Associated with CSA

Most common disorders:
  - Hyperventilation-related conditions
  - Cheyne-Stokes breathing pattern
  - Congestive heart failure
  - High-altitude periodic breathing
Hypoventilation-related conditions:
  - Secondary problems often related to underlying conditions, including:
    - Encephalitis
    - Brain stem neoplasms
    - Brain stem infarctions
    - Spinal surgery
    - Hypothyroidism
    - Drug or substance abuse, including alcohol and various sedatives

Mixed Sleep Apnea

Mixed sleep apnea consists of both obstructive and central apneas.
It typically starts with central apnea followed by obstructive apnea (absence of airflow despite ventilatory efforts).
Patients primarily classified with mixed apnea are treated as having OSA.

Diagnosis of Sleep Apnea

Diagnosis involves a thorough history from the patient or bed partner, focusing on:
  - Presence of snoring
  - Sleep disturbances
  - Persistent daytime sleepiness
A careful upper airway examination and possibly pulmonary function tests (PFTs) are conducted.
Blood analysis checks for:
  - Polycythemia
  - Reduced thyroid function
  - Bicarbonate retention
Arterial blood gases (ABG) evaluate resting oxygenation and acid-base balance.
When applicable, a carboxyhemoglobin level should be measured.
Diagnostic imaging, such as chest X-rays and echocardiograms, are beneficial for evaluating pulmonary hypertension and heart conditions.

Confirming Diagnosis and Type of Sleep Apnea

Multichannel polysomnographic sleep studies evaluate:
  - Sleep stages
  - Electroencephalogram (EEG) for brain activity
  - Electrooculogram (EOG) for eye movement and sleep stages
  - Electromyogram (EMG) for muscle activity
  - Chest and abdominal movement
  - Airflow (nasal and oral)
  - Presence of snoring
  - Oxygen saturation
  - Electrocardiogram (ECG)

Clinical Data for Sleep Apnea

Data may include:
Apnea or hypopnea events
Cyanosis
PFT findings—typically restrictive pathophysiology noted in obesity and congestive heart failure (CHF)
Often, CXR findings are normal, but right or left-sided heart failure may be present.

Cardiac Arrhythmias Associated with Sleep Apnea

Brady-tachy syndrome
Sinus arrhythmia
Sinus bradycardia
Sinus pause
Atrioventricular (AV) block (second degree)
Premature Ventricular Contractions (PVCs)
Supraventricular Tachycardia (SVT)
Ventricular tachycardia
Atrial fibrillation (A-fib)

Management of Obstructive Sleep Apnea

The most common and effective treatment for OSA is the use of CPAP (Continuous Positive Airway Pressure).
Role of CPAP:
- Prevents the collapse of hypotonic and obstructed airways.
- It’s considered the standard treatment for most OSA cases.
CPAP titration polysomnogram (PSG) is conducted in a sleep disorder laboratory to establish the lowest required CPAP pressure to maintain airway openness.

Therapeutic Strategies for OSA

Behavioral modifications:
  - Weight loss and exercise
  - Sleep position adjustments (condition worsens in the supine position)
  - Avoiding alcohol and certain sedative medications (e.g., benzodiazepines, opiates).
Potential surgeries include:
  - Uvulopalatopharyngoplasty (UPPP)
  - Laser-assisted uvulopalatoplasty (LAUP)
  - Mandibular advancement surgery

Management of Central Sleep Apnea

Adaptive servo-ventilation and Variable Positive Airway Pressure (VPAP) are used to provide ventilatory support for CSA, mixed apnea, and periodic breathing (e.g., Cheyne-Stokes respiration).
The ResMed VPAP Adapt SV adjusts pressure support in response to apneas, calculating target ventilation and required pressure to keep the airway open.

Therapeutic Strategies for CSA

VPAP – variable positive airway pressure adaptation
Phrenic nerve pacemaker
Drug therapies include:
- Protriptyline (Vivactil)
- Acetazolamide (Diamox)

Other Treatments for Sleep Apnea

Oxygen therapy
Pharmacologic Therapy:
  - Respiratory stimulants such as:
    - Acetazolamide
    - Theophylline
Medication details:
  - Acetazolamide
    - 250 mg tablets
  - Theophylline Extended-Release
    - 300 mg tablets
    - NDC: 50111-459-01
    - Rx only.
Prescribing information:
Note regarding prescribing and medical considerations for treatment.