resp. failure - obstructive sleep apnea (OSA)

what is OSA?

repeated episodes of airway obstruction during sleep

• due to muscle relaxation

how is happens?

• Muscles relax during sleep

• including those in the pharynx

• This relaxation causes airway collapse in some ppl

• Muscle tone decreases lots

• collapse obstructs airflow

• pressure decreases

• trachea closes

  • ⇓ O2

  • ⇑ CO2

• compensate

  • body wakes up from deep sleep

  • takes a deep breath

  • reopen airways

  • closes again

  • repeats multiple times per night

Diagnosis

A sleep study monitors

• Cessation of breathing (apnea)

• Respiratory effort

• Oxygen levels

The Apnea-Hypopnea Index (AHI) is used to classify severity:

measures how many times breathing partially (hypopnea) or completely (apnea) stops per hour during sleep.

• <5 = Normal

• 5–15 = Mild

• 15–30 = Moderate

• >30 = Severe

How OSA Affects Sleep, symptoms

Normally, sleep happens in cycles:

• Non-REM Sleep (N1, N2, N3)

  • N3 (Deep Sleep) is restorative for the body.

• REM Sleep (dreaming, memory processing)

in OSA:

Less REM sleep → Poor memory, focus, and mood.

Symptoms:

• Loud snoring (caused by airway blockage and turbulent airflow).

• Poor sleep quality → Waking up often, feeling unrested.

• Insomnia (difficulty staying asleep).

• Frequent urination at night (nocturia)

  • → Due to changes in chest pressure

  • stimulating the Atrial Natriuretic Peptide (ANP)

  • which increases urine production.

    • Swings of intrathoracic pressure

    • The heart releases Atrial Natriuretic Peptide (ANP)

    • tells the kidneys to increase urine production and reduce blood volume.

    • frequent nighttime urination

      • contributes to disrupted sleep and daytime fatigue

risk factors for OSA

1. obesity

   • extra weight narrows the airways

2. age

   • Men over 40

   • Muscle tone decreases with age

   • easier for airway to collapse

3. gender

   • Men are more at risk

   • menopause

     • ⇓ Estrogen levels = ⇓ in muscle tone

4. Alcohol and Sedative Use

   • Alcohol and sedatives

     • relax the muscles of the throat

     • easier for the airway to collapse during sleep.

how does OSA cause hypertension?