PBSG: Obstructive Sleep Apnea

What does STOP BANG stand for?

Snores

Tiredness (daytime)

Observed apnea

P Blood pressure elevated

BMI: Over 35

Age: Over 50

Neck circumference: Neck size large ( measured around adams apple). Male > 43cm (17 inches)/; Female > 41cm (16 inches)

Gender: Male

Low risk of OSA: Yes to 0-2 questions

Intermediate risk of OSA: Yes to 3-4 questions

High risk of OSA: Yes to 5-8 questions

or Yes to 2 or more of 4 STOP questions + male gender

or Yes to 2 or more of 4 STOP questions + BMI > 35 kg/m2

or Yes to 2 or more of 4 STOP questions + neck circumference (17”/43cm in male, 16”/41cm in female)

What is the Epworth sleepiness scale?

Helps identify subjective sleepiness and treatment response. Score 0-24. Score >15 indicates severe daytime sleepiness

What is the OSA diagnostic criteria?

Criteria to meet diagnosis include: A and B or C

A. The presence of > 1 of the following:

• Patient reports sleepiness, nonrestorative sleep, fatigue, or insomnia symptoms

• Patient wakes with gasping or choking

• Bed partner or another observer reports habitual snoring, breathing interruptions, or both

• Diagnosis of hypertension, a mood disorder, cognitive dysfunction, coronary artery disease, stroke, congestive heart failure, atrial fibrillation, or T2DM

Polysomnography or home sleep apnea testing reports:

B. >/= 5 predominantly obstructive respiratory events per hour of sleep during polysomnography or per hour of monitoring during home sleep apnea testing.

C. >/= 15 predominantly obstructive respiratory events per hours of sleep during polysomnography or per hour of monitoring during home sleep apnea testing

How do you classify severity of OSA?

Mild: AHI >/= 5 events/hour

Moderate: AHI >/= 15 events/hour

Severe: AHI >/= 30 events/hour

What is the Apnea-Hypopnea Index (AHI)?

Number of apneas and hypopneas per hour of total sleep time.

What is Respiratory event index (REI)

Number of apneas and hypopneas per hour of total recording time on home monitoring devices for sleep apnea.

What is the gold standard for diagnosis of OSA?

Level 1 study also known as polysomnography attended. This uses 7 or more data channels to collect data

• Electrodes to monitor brain waves, heart rate, muscle activity, O2 saturation, limb movement

• Chest belt that senses breathing

• Nasal cannula

• CPAP machine (only for undergoing titration)

What is a level 3 study?

Home sleep apnea testing. This records a minimum of 3 channels of data while the patient sleeps at home.

What are some limitations of level 3 sleep study?

Does not measure sleep and can only measure the respiratory event index (the # of apnea & hypopnea events per hour of total recording time). This underestimates AHI due to measuring time when the patient is not actually sleeping and does not detect arousals from sleep.

What does a level 3 sleep study measure?

• Measures the respiratory event index (the # of apnea & hypopnea events per hour of total recording time).

What type of healthy behavior change can be done to improve OSA?

• Moderate intensity exercise

• Weight loss (10% of baseline weight in patients who are overweight or obese)

Both result in modest reductions in AHI.

Can altering sleep position be an effective treatment for OSA?

• Yes, sleep position and/or the use of devices may reduce AHI by up to 10 events per hour for those with supine-predominant OSA

  • Sleeping on the side

  • Commercial devices (i.e. positional devices, sleep positioner alarm systems) may be more effective than placing a tennis ball in a tube sock & attaching it vertically in the centre of the back of a sleep shirt.

What types of surgery can be used to treat OSA?

• Bariatric surgery (i.e. if BMI >/= 35)

• Nasal procedures (i.e. nasal septoplasty, turbinate reduction) may increase tolerability of CPAP due to anatomical abnormalities

• Tonsillectomy & adenoidectomy may help when tonsillar enlargement encroaches on the upper airways, notably for younger patients

When is surgery indicated for OSA?

When patients are intolerant or unaccepting of CPAP

What are some common complaints of patients using CPAP that affect adherence?

• Nasal congestion

• Dry mouth/nose/eyes

• Skin irritation

• Claustrophobia

• Lare air leak

• Excessive moisture in tubing

• Tubing disruptive when moving in bed

• Machine noise

• General discomfort

• Abdominal bloating

What type of follow up should patients with CPAP have?

Short & Long term

Short: to support treatment adherence & response

Long: to confirm continued efficacy and monitor for comorbidities

What does the evidence show for the benefit of CPAP therapy?

• Reduces sleepiness

• Reduces risk of motor vehicle crashes

• Reduces BP

• In people with moderate to severe OSA, there may be a decreased recurrence of cardiovascular events/mortality in those with established CVD if they use CPAP for a minimum of 4 hours per day.