Decrease in the flow of air through the upper airway for 10 seconds with a pathologic decrease in the oxygen saturation or abrupt arousal from sleep
Complete airflow obstruction through the upper airway fro 10 seconds, with continued ventilatory effort- think of this traditionally in an obese man, but that is not necessarily the norm
What is the RDI?
includes obstructive events that don't meet hypopnea definition, but result in arousal which causes increased respiratory effort (events per hour)
Greater than or equal to 5 is diagnostic of OSA
Define Central apnea
apnea which occurs during sleep usually due to neurologic illness (often brainstem)
Define Cheyne-Stokes Respirations
A pattern of breathing that oscillates between apnea and hyperpnea
The body is trying to compensate for changing partial pressures of oxygen and carbon dioxide
Cheyne-stokes respirations are associated with what other health conditions?
stroke, CHF, brain tumor, traumatic brain injury (TBI), carbon monoxide poisoning,
T/F: Men are more likely to suffer from OSA
True - and obese post-menopausal women have incidence similar to men
What are 5 risk factors for OSA?
-Obesity, high BMI
-Craniofacial structural features
-Increased neck circumference
Name 7 signs/symptoms of OSA
-EDS - excessive daytime somnolence
People fall asleep easily/unexpectedly
Epworth Sleepiness Scale
-Mood disorders- because they are not sleeping at night and chronically not going through sleep cycles
-Witnessed apneas- usually by the spouse
-Nocturnal urination (especially in patients with high PCO2)
-Dry mouth in the morning
-Morning headaches- from CO2 retention, they are not ventilating well.
-Sometimes noticed when patient gets sedation, and apneas/hypopneas are more pronounced and frequent
-Close call or accident due to sleepiness
What is the grading of the Epworth Score
0 = would never doze or sleep.
1 = slight chance of dozing or sleeping
2 = moderate chance of dozing or sleeping
3 = high chance of dozing or sleeping
- Tallied for different situations. A score over 10 is high risk for OSA
What causes OSA?
-Neck muscles relax and cause upper airway to close off, and the patient to have a hypopnea or apnea.
-When the patient gets hypoxic, the body responds with elevated heart rate and blood pressure
What 6 tests does polysomnography include?
Polysomnography - overnight "sleep study"
-Electro-oculography (eye movements to detect REM)
-?transcutaneous carbon dioxide
-Leg and chin electromyography
What complications does OSA cause?
-Difficult to control, or new onset arrhythmias, especially Atrial fibrillation
-HTN, difficult to control
-Stroke, MI risk is increased
What is continous positive airway pressure?
-Delivers a fixed level of positive pressure to the upper airway to act as a splint to prevent airway collapse, and therefore prevent apneas and hypopneas
-First line treatment for patients diagnosed with straightforward OSA (and have had a successful CPAP titration study)
What is Bilevel Positive Airway Pressure?
-Inspiratory pressure is different than expiratory pressure
Sometimes is better tolerated than CPAP, more comfortable
BiPAP is helpful for whom?
Helpful in very obese patients for true hypoventilation, and severe OSA not effectively treated with CPAP
If patient is still hypoxic with PAP treatment, what else might they need?
supplemental oxygen (<= 90% saturation)
How to manage CPAP while performing PSG study?
-If RDI >5, CPAP titration
start at 5cm H2O, and titrate up until snoring and apneas/hypopneas resolve to RDI < 5
-Sometimes can do a split night study -
If it's so obvious in the first few hours that the patient has OSA, CPAP titration can be done the same night
-CPAP is subsequently set up fo home use
What are some CPAP mask options?
-Can use chin strap for mouth breathers
Full face mask
-Pillows + mouth mask
Patients with OSA should avoid what four substances?
sedatives, narcotics, benzodiazepines and alcohol