OSA/SLEEP APNEA Flashcards
What is the minimum Apnea-Hypopnea Index (AHI) required for an OSA diagnosis in a symptomatic patient?
A) 3 episodes/hour
B) 5 episodes/hour
C) 10 episodes/hour
D) 15 episodes/hour
Answer: B) 5 episodes/hour
Rationale: A diagnosis of OSA requires at least 5 episodes of apnea or hypopnea per hour (AHI ≥5) if the patient has relevant symptoms such as snoring, gasping, or daytime sleepiness.
OSA is defined on the basis of nocturnal and daytime symptoms as well as sleep study findings. Diagnosis requires the patient to have (1) either symptoms of nocturnal breathing disturbances (snoring, snorting, gasping, or breathing pauses during sleep) or daytime sleepiness or fatigue that occurs despite sufficient opportunity to sleep and is unexplained by other medical problems; and (2) five or more episodes of obstructive apnea or hypopnea per hour of sleep.
OSA also may be diagnosed in the absence of symptoms if the AHI is ≥15 episodes/h
Which of the following is NOT considered a major risk factor for OSA?
A) Obesity
B) Male sex
C) Older age
D) High arousal threshold
Answer: D) High arousal threshold
Rationale: While a high arousal threshold can affect OSA severity, it is not a major risk factor. The primary risk factors include obesity, male sex, and older age.
What is the physiological consequence of an obstructive apnea episode?
A) Increased lung volume
B) Enhanced pharyngeal muscle tone
C) Decreased oxygen saturation and/or cortical arousal
D) Reduced CO2 levels
Answer: C) Decreased oxygen saturation and/or cortical arousal
Rationale: Each episode of apnea results in a drop in oxygen saturation (≥3%) or cortical arousal, which leads to fragmented sleep.
Which anatomical structure is most commonly involved in airway collapse in OSA?
A) Epiglottis
B) Soft palate
C) Trachea
D) Diaphragm
Answer: B) Soft palate
Rationale: The soft palate is the most common site of airway collapse in OSA, although other sites such as the tongue base and lateral pharyngeal walls may also contribute.
Which condition is most strongly associated with increased risk for OSA?
A) Hyperthyroidism
B) Down syndrome
C) Marfan syndrome
D) Osteoporosis
Answer: B) Down syndrome
Rationale: Down syndrome increases OSA risk due to anatomical factors like macroglossia, midface hypoplasia, and hypotonia of airway muscles.
Which of the following is the best initial diagnostic test for suspected OSA?
A) Pulmonary function test
B) Multiple sleep latency test
C) Polysomnography
D) Arterial blood gas
Answer: C) Polysomnography
Rationale: A sleep study (polysomnography) is the gold standard for diagnosing OSA by measuring AHI and oxygen desaturation.
Which lifestyle change is most likely to improve OSA symptoms?
A) Increasing caffeine intake
B) Sleeping in a supine position
C) Losing weight
D) Increasing alcohol consumption
Answer: C) Losing weight
Rationale: Even modest weight loss can reduce airway narrowing and decrease OSA severity.
What effect does menopause have on OSA risk?
A) It has no effect
B) It decreases risk
C) It increases risk
D) It stabilizes pharyngeal muscle tone
Answer: C) It increases risk
Rationale: Menopause leads to a loss of protective effects from estrogen and progesterone, increasing OSA risk.
Which of the following is NOT a common symptom of OSA?
A) Snoring
B) Nocturnal gasping
C) Frequent awakenings
D) Hyperactivity
Answer: D) Hyperactivity
Rationale: Hyperactivity is more commonly seen in children with OSA, whereas adults typically experience excessive daytime sleepiness.
Which comorbidity is most strongly associated with OSA?
A) Chronic kidney disease
B) Hypertension
C) Crohn’s disease
D) Anemia
Answer: B) Hypertension
Rationale: OSA is a well-established risk factor for hypertension due to repeated oxygen desaturation and sympathetic activation.
Which intervention is considered first-line therapy for moderate-to-severe OSA?
A) Oxygen therapy
B) CPAP (continuous positive airway pressure)
C) Oral steroids
D) Beta-blockers
Answer: B) CPAP (continuous positive airway pressure)
Rationale: CPAP is the most effective treatment for moderate-to-severe OSA by preventing airway collapse.
What is the gold standard test for diagnosing obstructive sleep apnea (OSA)?
A) Home sleep apnea test
B) Overnight polysomnography (PSG)
C) Multiple sleep latency test (MSLT)
D) Cephalometric radiography
Answer: B) Overnight polysomnography (PSG)
Rationale: PSG is the most comprehensive and accurate test for diagnosing OSA as it measures multiple physiologic parameters, including breathing patterns, oxygenation, sleep stages, and arousals. Home sleep apnea tests are useful but may yield false-negative results.
What does the apnea-hypopnea index (AHI) measure?
A) The number of respiratory arousals per hour
B) The total number of apneas and hypopneas per hour of sleep
C) The time spent in deep sleep
D) The fluctuation of oxygen saturation throughout the night
Answer: B) The total number of apneas and hypopneas per hour of sleep
Rationale: AHI quantifies the severity of OSA by counting the number of obstructive events (apneas and hypopneas) per hour of sleep. It is the primary metric for diagnosing and grading OSA severity.
Which of the following is a key limitation of home sleep apnea testing?
A) It cannot detect changes in oxygen saturation
B) It lacks EEG recordings to measure sleep stages
C) It overestimates the severity of OSA
D) It is not useful for diagnosing severe OSA
Answer: B) It lacks EEG recordings to measure sleep stages
Rationale: Home sleep apnea tests do not record EEG, meaning they cannot precisely measure sleep stages or differentiate between sleep and wakefulness. This can lead to underestimation of AHI if total sleep time is not accurately estimated.
In-laboratory polysomnography measures all of the following parameters EXCEPT:
A) Oxygen saturation
B) Cardiac rhythm
C) Muscle tone
D) Serum hemoglobin levels
Answer: D) Serum hemoglobin levels
Rationale: PSG records multiple physiological signals, including breathing patterns, oxygen levels, cardiac activity, and muscle movements. However, it does not measure blood biomarkers like serum hemoglobin.
What sleep-related respiratory event is characterized by a ≥3% drop in oxygen saturation or a brain cortical arousal?
A) Central apnea
B) Hypopnea
C) Periodic limb movement
D) Cheyne-Stokes breathing
Answer: B) Hypopnea
Rationale: Hypopneas are characterized by a reduction in airflow that lasts at least 10 seconds and results in either a ≥3% drop in oxygen saturation or an arousal from sleep. They are a key component of OSA diagnosis.
Why is the “nondipping” pattern in overnight blood pressure monitoring significant in OSA?
A) It indicates an increased risk of cardiovascular disease
B) It confirms the presence of daytime hypertension
C) It rules out OSA in normotensive patients
D) It is a normal finding during sleep
Answer: A) It indicates an increased risk of cardiovascular disease
Rationale: Normally, blood pressure drops (~10%) during sleep. In OSA, frequent arousals and nocturnal hypoxia disrupt autonomic regulation, leading to a “nondipping” pattern, which is linked to higher cardiovascular risk.
Which of the following best defines an apneic event in obstructive sleep apnea (OSA)?
A) Cessation of airflow for at least 5 seconds during sleep
B) Partial reduction in airflow associated with a ≥3% oxygen desaturation
C) Cessation of airflow for at least 10 seconds with persistent respiratory effort
D) Absence of airflow with no respiratory effort for at least 20 seconds
Answer: C) Cessation of airflow for at least 10 seconds with persistent respiratory effort
Rationale: Apnea is defined as a complete cessation of airflow for at least 10 seconds. In OSA, this is accompanied by persistent respiratory effort, distinguishing it from central apnea, which is due to a lack of respiratory effort.
What is the primary difference between an apnea and a hypopnea?
A) Apnea involves complete cessation of airflow, while hypopnea is a partial reduction in airflow
B) Apnea lasts for at least 20 seconds, while hypopnea lasts for at least 10 seconds
C) Apnea occurs only during rapid eye movement (REM) sleep, while hypopnea occurs in all sleep stages
D) Apnea results in oxygen desaturation, while hypopnea does not
Answer: A) Apnea involves complete cessation of airflow, while hypopnea is a partial reduction in airflow
Rationale: Apnea is characterized by a complete stoppage of airflow for ≥10 seconds, while hypopnea is defined as a ≥30% reduction in airflow lasting at least 10 seconds, often with an associated ≥3% oxygen desaturation or arousal.
A patient undergoes an overnight polysomnography (PSG) and is found to have an apnea-hypopnea index (AHI) of 20 events per hour. How is their OSA severity classified?
A) Mild
B) Moderate
C) Severe
D) Borderline
Answer: B) Moderate
Rationale: The AHI quantifies OSA severity as follows:
Mild OSA: 5–14 events/hour
Moderate OSA: 15–29 events/hour
Severe OSA: ≥30 events/hour
An AHI of 20 falls within the moderate range.
Which of the following is true regarding the respiratory disturbance index (RDI)?
A) It includes only apneas and hypopneas per hour of sleep
B) It measures the number of arousals due to respiratory effort-related events
C) It is always lower than the AHI
D) It is measured only in home sleep studies
Answer: B) It measures the number of arousals due to respiratory effort-related events
Rationale: The RDI includes the number of apneas, hypopneas, and respiratory effort-related arousals (RERAs) per hour of sleep. Unlike AHI, which counts only apneas and hypopneas, RDI also considers events leading to sleep disruption without significant oxygen desaturation.
Which of the following best defines an apnea event in obstructive sleep apnea (OSA)?
A) A cessation of airflow for ≥5 seconds, regardless of respiratory effort
B) A cessation of airflow for ≥10 seconds, accompanied by persistent respiratory effort
C) A ≥30% reduction in airflow for at least 10 seconds with oxygen desaturation
D) A brief period of snoring followed by a sudden arousal from sleep
Answer:
B) A cessation of airflow for ≥10 seconds, accompanied by persistent respiratory effort
Rationale:
An apnea event is defined as a complete cessation of airflow for at least 10 seconds. In obstructive apnea, respiratory effort continues despite the airflow blockage. This distinguishes it from central apnea, where respiratory effort is absent.
What is the apnea-hypopnea index (AHI) threshold for diagnosing severe OSA?
A) ≥10 events per hour
B) ≥15 events per hour
C) ≥20 events per hour
D) ≥30 events per hour
Answer:
D) ≥30 events per hour
Rationale:
OSA severity is classified based on the AHI (Apnea-Hypopnea Index):
Mild OSA: AHI of 5–14 events/hour
Moderate OSA: AHI of 15–29 events/hour
Severe OSA: AHI of ≥30 events/hour
Which sleep stage is OSA typically most severe in?
A) Stage N1
B) Stage N2
C) Stage N3
D) REM sleep
Answer:
D) REM sleep
Rationale:
OSA is often most severe in REM sleep because neuromuscular output to the pharyngeal muscles is particularly low during this stage, increasing airway collapsibility.
What distinguishes the Respiratory Disturbance Index (RDI) from the Apnea-Hypopnea Index (AHI)?
A) RDI includes respiratory effort–related arousals (RERAs) in addition to apneas and hypopneas
B) RDI is always lower than AHI
C) RDI measures the severity of central sleep apnea, while AHI measures OSA
D) AHI accounts for oxygen saturation, while RDI does not
Answer:
A) RDI includes respiratory effort–related arousals (RERAs) in addition to apneas and hypopneas
Rationale:
RDI = AHI + RERAs
While AHI counts only apneas and hypopneas, RDI also includes RERAs, which are episodes of increased respiratory effort that cause arousals but do not meet the definition of hypopnea.
What is the most effective medical therapy for obstructive sleep apnea (OSA)?
A) Oral appliances
B) Continuous positive airway pressure (CPAP)
C) Upper airway surgery
D) Supplemental oxygen
Answer:
B) Continuous positive airway pressure (CPAP)
Rationale:
CPAP is the gold standard treatment for OSA, providing a mechanical splint to keep the airway open and improve breathing during sleep. It has been shown to improve symptoms, quality of life, and cardiovascular health.
Which of the following lifestyle modifications is NOT typically recommended for OSA patients?
A) Avoiding alcohol within 3 hours of bedtime
B) Increasing physical activity
C) Using sedative-hypnotic medications to promote sleep
D) Maintaining a consistent sleep schedule
Answer:
C) Using sedative-hypnotic medications to promote sleep
Rationale:
Sedative-hypnotic medications can worsen OSA by relaxing the airway muscles, making airway obstruction more likely. Patients with moderate to severe OSA should generally avoid these medications.
Why are oral appliances primarily recommended for patients with mild to moderate OSA?
A) They are more effective than CPAP in severe cases
B) They reduce the AHI by 100% in all patients
C) They reposition the lower jaw and pull the tongue forward, improving airflow
D) They have no side effects and work for all OSA patients
Answer:
C) They reposition the lower jaw and pull the tongue forward, improving airflow
Rationale:
Oral appliances advance the mandible, opening the airway. They are most effective in mild to moderate OSA, though some severe cases may also respond. Side effects can include jaw pain and tooth movement.
What is the primary purpose of an overnight CPAP titration study?
A) To determine the severity of OSA
B) To assess the impact of alcohol on sleep patterns
C) To find the optimal CPAP pressure setting for the patient
D) To determine if the patient is a candidate for oral appliances
Answer:
C) To find the optimal CPAP pressure setting for the patient
Rationale:
A CPAP titration study identifies the optimal air pressure needed to prevent apneas and hypopneas, improving sleep quality and oxygenation.
Which surgical procedure is the most commonly performed for OSA but is less effective than CPAP?
A) Mandibular advancement surgery
B) Uvulopalatopharyngoplasty (UPPP)
C) Bariatric surgery
D) Hypoglossal nerve stimulation
Answer:
B) Uvulopalatopharyngoplasty (UPPP)
Rationale:
UPPP involves removal of the uvula and part of the soft palate to reduce airway obstruction. While it can help with snoring and mild OSA, it is less effective than CPAP, especially in obese patients and those with severe OSA.
Which of the following is an emerging therapy for OSA that involves stimulating the hypoglossal nerve?
A) Oral appliances
B) Upper airway surgery
C) Upper airway neurostimulation
D) Radiofrequency ablation
Answer:
C) Upper airway neurostimulation
Rationale:
Upper airway neurostimulation stimulates the hypoglossal nerve, helping to maintain airway patency. It is an option for patients who cannot tolerate CPAP, but candidates must meet specific criteria (e.g., BMI <32 kg/m², moderate-severe OSA).
Why is supplemental oxygen NOT considered a first-line treatment for OSA?
A) It does not improve sleep quality or apnea-hypopnea index (AHI)
B) It is only used for patients with heart disease
C) It is more expensive than CPAP therapy
D) It eliminates the need for lifestyle modifications
Answer:
A) It does not improve sleep quality or apnea-hypopnea index (AHI)
Rationale:
While supplemental oxygen can improve oxygen saturation, it does not reduce the frequency of apneas and hypopneas or improve sleep architecture. There is also conflicting evidence regarding its effects on blood pressure in OSA patients.
