OSA Flashcards
What is Obstructive Sleep Apnea (OSA)?
OSA is a disorder characterized by recurrent obstruction of the upper airway during sleep, causing hypoxia and fragmented sleep. It can be a partial or complete collapse of the airway.
What is the difference between apnea and hypopnea?
Apnea is the cessation of breathing, while hypopnea is a decrement in airflow of 50% or more associated with a 4% fall in oxygen saturation or EEG arousal.
What is the Apnea-Hypopnea Index (AHI)?
The AHI is the number of apneas or hypopneas per hour of sleep. It is a laboratory finding used to assess the severity of sleep-disordered breathing.
What is the Respiratory Effort Related Event (RERA)?
RERA is a sequence of breaths characterized by increasing effort leading to an arousal from sleep that does not meet the criteria for apnea or hypopnea.
What is the gold standard diagnostic test for Obstructive Sleep Apnea (OSA)?
Polysomnography (PSG) is the gold standard diagnostic test for OSA.
What is the definition of OSA diagnosis according to the criteria?
Diagnosis requires nocturnal breathing disturbances (snoring, snorting, gasping) or daytime sleepiness/fatigue, along with an AHI of 5 or more episodes per hour of sleep documented during a sleep study.
What are the key symptoms of OSA?
Key symptoms include snoring, excessive daytime sleepiness, difficulty staying awake, and poor sleep quality despite adequate sleep duration.
How does the anatomy of the upper airway contribute to OSA?
In OSA, there is a reduction in neuromuscular output to pharyngeal muscles, leading to airway collapse, snoring, and sleep disruption during sleep.
What is the pathophysiology of OSA?
OSA pathophysiology involves a reduction in neuromuscular output, leading to collapse of the upper airway during sleep, causing intermittent apnea or hypopnea episodes.
How does sleep position affect OSA severity?
OSA is often more severe in the supine position due to gravitational forces on the airway.
What is the Modified Mallampati Classification used for?
The Modified Mallampati Classification is used to assess the ease of oral intubation based on the visibility of the soft palate, uvula, and other oral structures.
What are the different types of sleep?
The two main types of sleep are Slow-Wave Sleep (Non-REM sleep) and REM (Rapid Eye Movement) sleep.
What is Slow-Wave Sleep?
Slow-Wave Sleep, also known as non-REM sleep, is deep, restful sleep that typically occurs in the first hour of sleep.
What are the characteristics of REM sleep?
REM sleep is characterized by active dreaming, irregular heart rate and respiration, and greatly reduced muscle tone.
What is the role of the pharyngeal muscles in OSA?
The pharyngeal muscles maintain airway patency during wakefulness. In OSA, their reduced neuromuscular output leads to airway collapse during sleep.
What is the significance of BMI in diagnosing OSA?
A BMI of 40kg/m2 or higher is classified as Type III obesity, which is a significant risk factor for OSA.
How does sleep fragmentation affect OSA patients?
Sleep fragmentation due to OSA can result in excessive daytime sleepiness and reduced cognitive performance.
What are common physical examination findings in OSA patients?
Obesity, hypertension, large neck circumference, macroglossia, and signs of heart failure are common physical findings in OSA patients.
What is the role of sympathetic surge in OSA?
In OSA, sympathetic surge occurs due to hypoxemia, leading to tachycardia and increased blood pressure.
What are common coexisting symptoms with OSA?
Common coexisting symptoms include dry mouth, nocturnal heartburn, diaphoresis, and morning headaches.
Why is a sleep study necessary for diagnosing OSA?
A sleep study, such as PSG, is necessary to confirm the diagnosis of OSA by measuring the AHI and other parameters during sleep.
STOP-Bang Questionnaire
More specific for OSA, more encompassing on the risk factors, and more objective in looking for risk factors in patients who might have OSA.
0-2 = low risk
3 or 4 =. intermediate risk
>/=5 = high risk
Gold standard for diagnosis of OSA, can be done as overnight or split-night study.
Polysomnography (PSG)
Overnight PSG vs Split-night PSG
Overnight PSG involves 8 hours of observation and intervention, while split-night PSG involves 4 hours of observation followed by 4 hours of intervention.
Negative PSG result
A negative PSG rules out OSA.
Components of PSG
EEG to monitor brain waves,
EOG for REM stage,
nasal thermistor for airflow,
mouth transducer,
microphone to record snoring,
chin strap for chin movement,
ECG to monitor arrhythmias,
chest and abdominal strap to differentiate between OSA and CSA,
pulse oximeter for oxygenation.
Apnea-Hypopnea Index (AHI)
Number of apneas and hypopneas per hour of sleep.
Respiratory Disturbance Index (RDI)
Number of apneas, hypopneas, and RERAs per hour of sleep.
Mild OSAHS AHI range
AHI of 5-14 events per hour.
Moderate OSAHS AHI range
AHI of 15-29 events per hour.
Severe OSAHS AHI range
AHI of greater than 30 events per hour.
Sleep forensic study
A sleep study used in psychopath criminals to determine whether they are telling the truth.
Polysomnography criteria for Apnea
Absence of breathing for 10 seconds or more during sleep, with either persistent or absent respiratory effort.
Polysomnography criteria for Hypopnea
Reduction in airflow by 30% for at least 10 seconds with >30% desaturation or arousal.
Respiratory Effort Related Arousal (RERA)
Partial obstruction not meeting hypopnea criteria but with increasing inspiratory effort and an arousal.
Sleep stages - REM vs NREM
Sleep stages are divided into REM (rapid eye movement) and NREM (non-rapid eye movement). REM is associated with vivid dreaming, while NREM has stages N1, N2, and N3, with N3 being deep sleep.
Stage 1 NREM characteristics
Characterized by lowered brain activity, blood pressure, and muscle tone.
Stage 2 NREM characteristics
Characterized by decreasing muscular activity and loss of conscious awareness of the external environment.
Stage 3 NREM characteristics
Deep sleep occurring 30-45 minutes after falling asleep, with regular breathing and slow brain waves.
REM sleep characteristics
The deepest sleep stage, characterized by partial paralysis, vivid dreaming, and EEG resembling waking brain activity.
CPAP function
Continuous Positive Airway Pressure (CPAP) keeps the airway open during sleep, reducing apneas and improving sleep quality.
Disadvantages of nasal inserts for CPAP
Nasal inserts tend to leak and dry the nasal cavity.
Disadvantages of nasal mask for CPAP
Nasal masks can cause soreness on the nasal bridge.
Micro CPAP
Not yet available in the Philippines, it starts at a 10 cm H2O pressure and adjusts based on the patient’s tolerance to eliminate desaturation and ECG abnormalities.
Standard treatment for OSA
Continuous Positive Airway Pressure (CPAP) is the standard treatment for OSA.
Surgical treatments for OSA
Includes Uvulopalatopharyngoplasty (UVPP),
genioglossus advancement,
mandibular advancement,
bariatric surgery,
tonsillectomy, and
tracheostomy.
Neurostimulation for OSA
Unilateral stimulation of the hypoglossal nerve through a surgically implanted device to prevent soft palate collapse and maintain the airway.
CPAP effect on OSA symptoms in the short term
CPAP improves OSA symptoms within one month of use.
CPAP effect on blood pressure in the long term
CPAP helps control blood pressure after long-term use (>1 year).
CPAP effect on heart failure symptoms in the long term
CPAP helps reduce heart failure symptoms after long-term use (>1 year).
