98 Questions
What is the defining characteristic of an apnea event?
Decrease in respiratory flow of 90% or more for at least 10 seconds
How is a hypopnea event characterized?
Decrease in respiratory flow by 30% with a Decrease in SpO2 of only 4% .
What is a key characteristic of a respiratory event-related arousal?
Flattening of the nasal pressure waveform
When does a hypopnea event occur with a decrease in SpO2 of only 3%?
When there is a decrease in respiratory flow of 40% from baseline
What defines hypoventilation?
Increase in PaCO2 by at least 10%
What is the major determinant of minute ventilation during sleep?
PaCO2 levels
What can occur during sleep to offset critical hypoxia levels?
arousal from sleep
What is a common value for PaCO2 during stable sleep?
45 mm Hg
Which factor challenges ventilatory control during sleep stages and can lead to instability in breathing?
Decreased arousal threshold
What does loop gain assess in the context of ventilatory control?
Propensity for periodic breathing
Why does the ventilatory response differ between wakefulness and sleep?
Decreased chemo sensitivity to CO2 during sleep
Why are patients with high loop gain more vulnerable to disturbances in the feedback system during sleep?
As a result of slight hypoventilation
In the context of sleep disordered breathing, what event may occur due to marked reduction or cessation of brainstem respiratory motor output?
Apnea event
Which factor helps in specifying sleep disordered breathing into obstructive or central events?
Predominant type of respiratory events
How is the severity of sleep disordered breathing usually quantified?
By the number of arousals per hour of sleep
What defines the respiratory disturbance index (RDI) used to measure the severity of sleep disordered breathing?
number of hypopneas, apneas, and arousals related to respiratory events per hour of sleep
What is the key diagnostic criterion for obstructive sleep apnea (OSA)?
15 or more predominantly obstructive events per sleep hour
How is the severity of obstructive sleep apnea (OSA) typically measured?
Using the Respiratory Disturbance Index (RDI) or Apnea-Hypopnea Index (AHI)
What additional criteria can qualify a patient with 5-15 obstructive events per sleep hour as having obstructive sleep apnea (OSA)?
Presence of comorbidities like hypertension (HTN) or atrial fibrillation (AF)
How is respiratory disturbance quantified in the context of obstructive sleep apnea (OSA)?
Using the Apnea-Hypopnea Index (AHI) or Respiratory Disturbance Index (RDI)
What criterion helps in distinguishing between obstructive and central events in sleep disordered breathing?
Pattern of airflow and respiratory effort during events
What is a major risk factor for obstructive sleep apnea (OSA)?
History of myocardial infarction
What percentage of individuals undergoing bariatric surgery may experience OSA?
77.5%
Which symptom is NOT commonly associated with nighttime in obstructive sleep apnea (OSA)?
restorative sleep
Who is more susceptible to obstructive sleep apnea (OSA) following surgery?
Individuals with a history of stroke
In which group can obstructive sleep apnea (OSA) be prevalent up to 24% without daytime symptoms?
Men aged 30-60
What serious medical consequences are associated with Obstructive Sleep Apnea (OSA)?
Hypertension, Myocardial Infarction, Stroke, Diabetic Neuropathy
What brain structures atrophy in patients with OSA leading to cognitive impairment?
Hippocampal areas
What cardiovascular effect is potentially associated with even asymptomatic OSA?
Altered daytime autonomic regulation
How can the atrophy of brain structures relevant for cognition and memory be influenced in OSA patients?
It can be partially reversed by adequate treatment
Which of the following is a potential consequence of cognitive dysfunction in OSA patients?
Increased likelihood of motor vehicle accidents
What is the role of upper airway dilator muscles in respiratory events during OSA?
Stabilizing the upper airway by balancing negative pressure generated by the respiratory pump
What is the main consequence of decreased airway dilator muscle activity during OSA?
Airway collapse with persisting respiratory effort
Which muscles are part of the upper airway dilator muscles involved in OSA?
Genioglossus and tensor palatini
What is the function of the genioglossus muscle in response to negative pharyngeal pressure during inspiration?
Reflexively stabilizing the upper airway
How do upper airway dilator muscles help maintain airway patency?
By balancing dilating forces with collapsing forces
What is the primary function of respiratory pump muscles during the breathing cycle?
Generate negative intraluminal pressure
What can further increase the collapsing effects of excessive pharyngeal extraluminal soft tissue in obese patients?
Craniofacial abnormalities
Which position makes the upper airway more vulnerable to collapse due to gravitational effects?
Supine
How can excessive intravenous fluid administration affect upper airway patency?
Increase neck circumference
What determines the extraluminal pressure antagonized by the upper airway dilator muscle contraction during inspiration?
Size and shape of the bony enclosure
How does nocturnal redistribution of fluid from lower extremities into the neck affect upper airway collapsibility?
Increases upper airway collapsibility
How do higher end-expiratory lung volumes affect upper airway resistance in awake healthy humans?
Decrease upper airway resistance
What do stretching forces on the fixed trachea due to longitudinal traction result in?
Decreased upper airway resistance
How does lung inflation during inspiration affect the carina?
Forces it into a more caudal position
What is the primary function of the respiratory pump during the breathing cycle?
Generating negative intraluminal pressure
What accounts for the majority of lung volume change during quiet respiration?
diaphragm
What happens when the intraluminal pressure in the upper airway becomes negative?
The airway collapses
critical airway pressure (Pcrit) in individuals with obstructive sleep apnea (OSA) ?
upper airway in patients with OSA may even collapse at a positive Pcrit.
In patients with obstructive sleep apnea (OSA), what type of pressure is required to reopen a paralyzed airway?
Positive intraluminal pressure
Which input contributes to the restoration of breathing following apnea by sensing negative pressure generated by the respiratory pump?
Sensors in the upper airway
What can independently restore tone to respiratory muscles during obstructive apneas?
Hypercarbia and upper airway negative pressure
What determines the level of drive provided to respiratory muscles in the context of restoring breathing after apnea?
Summation of stimuli in the central pattern generator output
What is the main benefit of continuous positive airway pressure (CPAP) treatment for obstructive sleep apnea (OSA)?
improved quality of life
How does the application of CPAP or BPAP typically help in treating sleep-disordered breathing (SDB)?
It reverses underlying pathology
Why is patient adherence to CPAP treatment for OSA often limited?
Because of local side-effects at the nose or face
What is a major drawback of applying high pressure during CPAP treatment?
Causes discomfort to the patient
What factor determines the range of CPAP level required for the treatment of OSA?
Severity of OSA
How does successful treatment of obstructive sleep apnea (OSA) impact cardiovascular risk?
Reduces cardiovascular risk
What function do some treatment devices offer to help patients fall asleep more easily?
Gradually increasing treatment pressure
In which patients is bilevel treatment with reduced expiratory pressure and high inspiratory pressure useful?
Patients with difficulties exhaling against high CPAP
What type of CPAP devices can improve treatment success in patients with variable severity of sleep disordered breathing?
CPAP devices with dynamic pressure levels
What do auto-titrating devices measure to adjust airway pressure for hypopnea?
Oropharyngeal wall vibration and inspiratory flow limitation
Which patients may require noninvasive ventilation with predefined respiratory frequency or timing?
Patients with predominantly central apneas
What is the primary method recommended for most patients with OSA?
CPAP therapy
Which type of oral appliance for OSA treatment involves repositioning the mandible without protrusion?
Tongue-retaining device
What is a recommended treatment for adults with OSA due to tonsillar hypertrophy?
Tonsillectomy
When is a tonsillectomy recommended for children with OSA?
For children with adenotonsillar hypertrophy
Which intervention for OSA involves causing genioglossus muscle contraction to increase airflow?
Hypoglossal nerve stimulation
Although OSA is more common in the older population, it occurs in children with a peak in the incidence between?
2- 5 years old
What is not recommended as a primary treatment for OSA but may be used adjunctively in some patients?
$O_2$ therapy
What distinguishes Central Sleep Apnea (CSA) from Obstructive Sleep Apnea (OSA)?
absence of respiratory effort in CSA compared to Presence of respiratory effort in OSA
Which of the following comorbidities is commonly associated with Central Sleep Apnea (CSA)?
Congestive Heart Failure (CHF)
What characterizes Cheyne-Stokes Respiration (CSR) seen in patients with Central Sleep Apnea (CSA)?
Crescendo-decrescendo pattern of hyperventilation followed by hypopneas or apneas
Which group has a higher prevalence of Central Sleep Apnea with an increased loop gain, specifically showing Cheyne-Stokes Respiration (CSR)?
Patients with Congestive Heart Failure (CHF)
What is a potential respiratory therapy option for patients experiencing Cheyne-Stokes Respiration (CSR)?
Noninvasive ventilation like bilevel positive airway pressure (BiPAP)
What is a distinguishing characteristic of Cheyne-Stokes Respiration (CSR) found in patients with Central Sleep Apnea?
Occurs mainly in the supine body position
What is the best treatment for patients experiencing Cheyne-Stokes Respiration (CSR)?
adequate treatment of CHF
what is The most common subtype of Central Sleep Apnea ?
CSR in high loop gain
CSR is defined as a crescendo-decrescendo pattern of hyperventilation between 20 and 30 seconds in duration, followed by 10 to 40 seconds of hypopneas or apneas , usually occurring during ?
NREM sleep stage 1 and 2
Central Sleep Apnea (CSA) most commonly occur in patients with?
congestive heart failure
CSR is defined as a crescendo-decrescendo pattern of hyperventilation between 20 and 30 seconds in duration, followed by 10 to 40 seconds of hypopneas or apneas
CSR is more common in men and worse in the supine body position.
What is a characteristic of Periodic Breathing induced by high altitude?
Hypoxia with increased controller gain
What distinguishes Idiopathic Central Sleep Apnea (CSA) from other forms of CSA?
Hypocapnia with high controller gain
In individuals with Idiopathic CSA, what tends to be the usual PaCO2 levels?
Low
What percentage of patients with a BMI of 50 kg/m2 or higher may experience obesity hypoventilation syndrome (OHS)?
Up to 50%
Which of the following is a common characteristic of obese patients with OHS ?
Nocturnal and daytime alveolar hypoventilation
What is one potential consequence of abolishing the compensatory respiratory drive in obese individuals ?
hypercapnia
What is a characteristic feature of patients with OHS ?
Normal CO2 response
What is the main defining characteristic of obesity hypoventilation syndrome (OHS)?
Combination of nocturnal and daytime alveolar hypoventilation
What is a potential cause of alveolar hypoventilation leading to hypercapnia in OHS?
Leptin resistance
In obese patients with OHS, what percentage of individuals may also experience OSA?
90%
Which respiratory parameter is typically reduced in patients with obesity hypoventilation syndrome (OHS)?
Expiratory reserve volume
Why does severe obesity lead to an increase in respiratory drive ?
To compensate for abnormal chest wall mechanics and maintain eucapnia
What is the difference between obese patients and patients with OHS ?
OHS patients has decrease in respiratory drive
What is a common cause of alveolar hypoventilation leading to hypercapnia in patients with obesity hypoventilation syndrome (OHS)?
Central hypoventilation
Which condition is NOT a known mechanism of alveolar hypoventilation?
Pulmonary embolism
Treatment options for patients with ○ Obesity hypoventilation syndrome (OHS) include ?
weight loss and NIV.
Learn the criteria for defining respiratory events such as apnea, hypopnea, and respiratory event-related arousal. Understand the percentage decrease in respiratory flow from baseline and the SpO2 levels required to classify each type of event.
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