42 Sleep Disordered Breathing Flashcards
1
Q
Obstructive sleep disordered breathing
- An obstructive apnea (OSA)
- An obstructive hypopnea
- A variety of methods are available to measure…
- Airflow cessation (apnea)
- Limitation (hypopnea) during sleep
- The accuracy of measuring airflow limitation can be substantially influenced by…
A
- An obstructive apnea (OSA)
- The lack of airflow measured at the nose and mouth for 10 seconds or longer during sleep despite ongoing effort to breathe
- Usually associated with a decrease in the oxyhemoglobin saturation and a change in the electroencephalogram (EEG) indicating arousal from sleep
- An obstructive hypopnea
- A decrease in airflow (generally > 30%) at the nose and mouth despite ongoing effort to breathe
- Associated with a decrease in the oxyhemoglobin saturation and a change in the EEG indicating arousal from sleep
- A variety of methods are available to measure…
- Airflow cessation (apnea)
- Apneas in adults are easily identified even with simple monitoring devices such as thermal sensors (thermisters or thermocouples)
- Limitation (hypopnea) during sleep
- This is not the case for airflow limitation (i.e. hypopnea)
- Airflow cessation (apnea)
- The accuracy of measuring airflow limitation can be substantially influenced by…
- The method of measurement
2
Q
Obstructive sleep disordered breathing
- On polysomnography (PSG), both apneas and hypopneas are commonly associated with…
- In current clinical practice, hypopneas that are accepted as physiologically significant events
- Apnea / hypopnea index (AHI) to rate syndrome severity
- Mild OSAH
- Moderate OSAH
- Severe OSAH
- Other metrics of sleep apnea
A
- On polysomnography (PSG), both apneas and hypopneas are commonly associated with…
- Changes on the EEG as a marker of sleep disruption
- However, the intra- and inter-rater reliability of visually scoring arousals is variable
- In current clinical practice, hypopneas that are accepted as physiologically significant events
- > 4 % desaturations, without arousal criteria
- Apnea / hypopnea index (AHI) to rate syndrome severity
- Mild OSAH
- An AHI between 5 and 15 events per hour of sleep
- Moderate OSAH
- An AHI of 15 to 30 events per hour of sleep
- Severe OSAH
- An AHI of greater than 30 events per hour of sleep
- Mild OSAH
- Other metrics of sleep apnea
- Symptoms related to disrupted sleep
- The degree and severity of oxygen desaturation
- The presence of concomitant cardiovascular conditions that might be adversely impacted by sleep apnea
3
Q
Epidemiology
- In predominately Caucasian middle-aged cohorts, the prevalence of OSAH…
- Gender
- The prevalence of OSAH in middle aged individuals
- Menopause and obesity
- Race
- What contributes relatively more to OSAH occurrence than obesity in African Americans
- Advancing age and increasing weight
- Age
A
- In predominately Caucasian middle-aged cohorts, the prevalence of OSAH…
- Defined as AHI > 10 plus symptoms of daytime sleepiness and / or hypertension
- ~5%
- Gender
- Increased risk in men, with a prevalence of 3.3:1 compared to women
- The prevalence of OSAH in middle aged individuals
- 4% for men and 2% for women
- Menopause and obesity
- Increase the risk of OSAH
- Race
- The prevalence of OSAH is higher in African Americans as opposed to the Caucasians
- What contributes relatively more to OSAH occurrence than obesity in African Americans
- Facial structure
- Advancing age and increasing weight
- Independently increase the risk of OSAH
- Age
- The age effect appears to plateau after age 65
- There may be an increase in mortality in middle age or possibly remission of OSAH in the elderly population
4
Q
Pathophysiology
- The upper airway in humans is able to perform a variety of complex functions,
including. .. - This is possible in part, because of…
- What may cause narrowing (hypopnea) or closure (apnea)
- What produces snoring sounds
- The primary cause for airway closure during sleep
- Major determinants of a small airway in adults
- Individuals with OSAH: awake vs. asleep
- The uniform stimulus for resumption of normal breathing
A
- The upper airway in humans is able to perform a variety of complex functions,
including. ..- Breathing, swallowing, and speaking
- This is possible in part, because of…
- The lack of rigid support from bone or cartilaginous tissue in the retro-palatal and retro-lingual airway
- What may cause narrowing (hypopnea) or closure (apnea)
- When increased negative intrathoracic pressure results in a suction force applied to a small, compliant, upper airway
- What produces snoring sounds
- The vibration of the narrowed airway
- The primary cause for airway closure during sleep
- A small airway
- Major determinants of a small airway in adults
- Craniofacial structure and function, in addition to obesity
- Individuals with OSAH: awake vs. asleep
- Able to maintain airway patency during wakefulness
- When transition occurs from wake to the sleeping state, muscle tone decreases and snoring, airway narrowing and /or closure may occur in individuals with a “vulnerable airway”
- The uniform stimulus for resumption of normal breathing
- A ventilatory related arousal from sleep
- The arousal can usually be identified on the EEG channel when sleep and breathing are measured in the laboratory
- The ventilatory related arousal may be precipitated by increased airway resistance (usually associated with snoring), hypopnea, or apnea
5
Q
Pathophysiology:
Other important physiologic perturbations occur in conjunction with the sleep disordered breathing events
- Struggling against a partially or completely closed airway is associated with…
- The ensuing arousal is accompanied by…
- These phenomena have acute and chronic effects on…
- Intermittent hypoxemia
- The ischemia-reperfusion associated with intermittent hypoxemia results in…
- A number of bio-markers that have been linked to risk and progression of cardiovascular disease in addition to altered metabolic function
A
- Struggling against a partially or completely closed airway is associated with…
- Increased intrathoracic pressure, hypoventilation, and increased vagal tone
- The ensuing arousal is accompanied by…
- Augmentation of sympathetic tone
- These phenomena have acute and chronic effects on cardiovascular function
- Acute changes are manifest as bradycardia followed by tachycardia (i.e. heart rate variability)
- Over time, sympathetic tone is upregulated not only nocturnally but also diurnally
- Intermittent hypoxemia
- A hallmark of OSAH
- The ischemia-reperfusion associated with intermittent hypoxemia results in…
- Transcription and translation of bio-markers of oxidative stress and subsequent endothelial dysfunction
- A number of bio-markers that have been linked to risk and progression of cardiovascular disease in addition to altered metabolic function
- C-reactive protein and Interleukin 6
6
Q
Consequences:
OSAH is associated with significant co-morbidities that are the result of the altered nocturnal physiology
- These co-morbidities can be broadly grouped into three categories
- These co-morbidities appear to have…
- Adequate treatment of OSAH
A
- These co-morbidities can be broadly grouped into three categories
- Cardiovascular
- Metabolic
- Neurocognitive
- These co-morbidities appear to have…
- A dose response effect with regard to the severity of OSAH
- Adequate treatment of OSAH
- Primarily with positive pressure
- Favorably impacts these co-morbidities
7
Q
Cardiovascular complications
- The normal cardiovascular response to sleep
- Acute and chronic physiological effects related to sleep disordered breathing
- Risk is increased for…
- A link between the AHI and cardiovascular complications
- Relationship between apnea and hypopnea and incident hypertension
A
- The normal cardiovascular response to sleep
- Includes a physiologic decrease in blood pressure and heart rate
- Negatively impacted in OSAH
- Acute and chronic physiological effects related to sleep disordered breathing
- The repetitive bursts of sympathetic activity triggered by the sleep disordered breathing events adversely affect nocturnal blood pressure and heart rate
- Over time, a profound toll is taken on the cardiovascular system
- Risk is increased for…
- Diurnal systemic hypertension, diurnal pulmonary hypertension, atrial dysrhythmias, heart failure (systolic and diastolic), myocardial infarction, and stroke
- A link between the AHI and cardiovascular complications
- The best evidence exists for diurnal systemic hypertension
- Relationship between apnea and hypopnea and incident hypertension
- After controlling for known confounding risk factors for the development of hypertension (smoking, alcohol weight, age, and sex), a dose response relationship exists
8
Q
Metabolic complications
- Relationship between AHI and bio-markers of the metabolic syndrome
- This relationship persists after controlling for…
- Leptin
- Obesity and leptin
A
- Relationship between AHI and bio-markers of the metabolic syndrome
- Dose response relationship between the AHI and bio-markers of the metabolic syndrome (serum glucose and insulin sensitivity)
- This relationship persists after controlling for…
- Concomitant obesity
- Leptin
- An adipokine that appears to play an important role in metabolic and ventilatory control
- Elevated in OSAH
- Inhibits the synthesis of neuropeptide Y, a potent stimulator of food intake
- Obesity and leptin
- Obese individuals typically have elevated circulating leptin levels suggesting leptin resistance
- The elevated leptin levels are not explained by obesity alone
- Leptin levels in patients with OSAH are elevated compared to matched obese controls, suggesting a direct effect of sleep disordered breathing
9
Q
Neurocognitive complications
- Daytime sleepiness
- Severity of sleep disordered breathing vs. daytime sleepiness
- The severity of OSAH also correlates with…
A
- Daytime sleepiness
- One of the defining features of the OSAH syndrome
- Severity of sleep disordered breathing vs. daytime sleepiness
- There is a dose response relationship between the severity of sleep disordered breathing and the complaint of daytime sleepiness
- The severity of OSAH also correlates with…
- The risk of motor vehicle and occupational accidents
- After adjusting for a number of confounding variables to include body-mass index, alcohol consumption, eyesight, medications, driving experience, and sleep schedule, subjects with a AHI of > 10 had a 7.2 odds ratio for having a traffic accident
- The risk for occupational accidents in sleepy snorers was 2.2 times that of the control population
10
Q
Neurocognitive complications
- Untreated OSAH was associated with…
- Significant impact on…
- Negligible impact on…
- Questionable association between…
- Sleepiness and impaired cognitive function undoubtedly…
A
- Untreated OSAH was associated with…
- Significant impact on vigilance, executive functioning, and coordination
- Negligible impact on intellectual and verbal functioning
- Questionable association between depression and OSAH
- Sleepiness and impaired cognitive function undoubtedly impact on quality of life
11
Q
Clinical presentation:
Findings on the history and physical associated with the presence of OSA
- The signs and symptoms that suggest the diagnosis of OSAH
- What may be present
- What may place selected individuals at risk for airway closure during sleep
- Signs that may be associated with occult OSAH
A
- The signs and symptoms that suggest the diagnosis of OSAH
- Nightly loud snoring
- Breathing pauses during sleep
- Snorting
- Choking
- Subjective daytime sleepiness
- What may be present
- Obesity (particularly upper body obesity)
- Systemic hypertension
- What may place selected individuals at risk for airway closure during sleep
- Craniofacial abnormalities (retro or micrognathia)
- Soft tissue abnormalities, such as…
- Enlarged tonsils
- Lateral narrowing of the airway
- An elongated soft palate
- Signs that may be associated with occult OSAH
- Right sided heart failure in the absence of established heart disease
12
Q
Laboratory testing
- Standard for confirming a diagnosis of OSAH in the US
- Sleep stages
- Sleep is analyzed by measuring…
- Cardiopulmonary parameters are measured, including…
- Sensors are applied to the legs in order to identify…
- Less intensive (and less expensive) alternatives to laboratory polysomnography
A
- Standard for confirming a diagnosis of OSAH in the US
- Objective measurement and quantification of sleep and breathing in a sleep laboratory
- Sleep stages
- Identified in addition to the degree of sleep disruption that is due to sleep disordered breathing events
- Sleep is analyzed by measuring…
- Electoroencephalographic (via a central lead)
- Bilateral electrooculographic
- Submental electromyographic (chin) activity
- Cardiopulmonary parameters are measured, including…
- Airflow, breathing effort, oximetry, and electrocardiogram
- Sensors are applied to the legs in order to identify…
- Periodic leg movements that may be responsible for disrupting sleep
- Less intensive (and less expensive) alternatives to laboratory polysomnography
- Accurate at diagnosing OSAH in patients with a moderate or high pre-test probability for the disease
- These portable monitor studies include single (or multiple) night continuous measurement of one or more cardiopulmonary parameters, generally pulse oximetry, heart rate, nasal airflow and / or respiratory effort
- Home sleep tests do not actually measure sleep
13
Q
Lifestyle interventions
- Relevant lifestyle interventions
- Weight loss
- Alcohol and sedatives
- Positioning
A
- Relevant lifestyle interventions
- Positive pressure administered via a mask remains the initial treatment of choice
- Second line therapy can involve oral appliance therapy and, in selected patients, upper airway surgery
- Weight loss
- Obesity is a major risk factor for OSAH
- Weight loss has been demonstrated to improve both sleep and breathing
- Avoiding sleep deprivation will not only decrease daytime sleepiness related to sleep debt but also increase upper airway muscle tone
- Alcohol and sedatives
- Also negatively affect upper airway muscle tone
- The magnitude of the impact of sedatives on the unstable upper airway is not well defined
- Positioning
- If the patient has clearly has positional OSAH, lateral positioning or head of bed elevation may be helpful
14
Q
Positive pressure therapy
- Reliably treats…
- Works primarily by…
- When a proper positive pressure prescription is performed…
- Can be applied as…
- Positive pressure therapy (primarily CPAP)
- Has a favorable effect on…
- CPAP improves…
A
- Reliably treats airway closure during sleep
- Works primarily by “pneumatically splinting” the airway open during sleep
- When a proper positive pressure prescription is performed, the treatment effect is virtually immediate
- Can be applied as…
- Continuous positive airway pressure (CPAP)
- Bi-level positive airway pressure (BPAP)
- The pressure setting during inspiration is higher than expiration, taking advantage of the fact that during inspiration the airway pressure is more negative than during expiration
- This is accomplished by the machine sensing changes in airflow associated with breathing
- Both CPAP and BPAP machines are electrically operated and are highly portable, usually weighing less than 10 pounds
- Positive pressure therapy (primarily CPAP)
- Has a favorable effect on quality of life, objective daytime function, and blood pressure
- CPAP improves insulin sensitivity, left ventricular function, pulmonary hypertension, endothelial function, and cardiovascular and overall mortality
15
Q
Positive pressure therapy
- Despite its effectiveness, objective adherence to therapy is similar to…
- Acceptance and adherence to positive pressure can be improved with…
- In general, CPAP or BPAP is delivered via…
- Patients with OSAH frequently report symptoms of…
- When the mouth opens, the machine…
- Heated humidifiers in-line with the CPAP/BPAP unit can frequently…
- What can occasionally be helpful
- What can be helpful in patients who are claustrophobic
A
- Despite its effectiveness, objective adherence to therapy is similar to…
- Most medical regimens at approximately 50% without structured educational interventions
- Acceptance and adherence to positive pressure can be improved with…
- Patient education
- Appropriate attention to patient – machine related problems
- In general, CPAP or BPAP is delivered via…
- A nasal interface
- Proper fit is essential
- Nasal congestion and / or dryness need to be treated
- Patients with OSAH frequently report symptoms of…
- Nasal congestion prior to treatment
- This problem can be exacerbated by positive pressure therapy
- The airflow through the nose at flow rates of 30 to 60 liters per minute (depending on the seal) can be drying to nasal mucosa
- This frequently triggers rebound nasal congestion that precipitates mouth breathing
- When the mouth opens, the machine…
- Increases the flow to maintain the set pressure exacerbating the congestion
- Heated humidifiers in-line with the CPAP/BPAP unit can frequently…
- Improve the nasal dryness and subsequent congestion
- What can occasionally be helpful
- A mask that covers both the nose and mouth
- What can be helpful in patients who are claustrophobic
- Desensitization
16
Q
Oral appliance therapy
- The goal of oral appliance therapy (OAP)
- Second line therapy for OSAH because…
- Effectiveness of OAP
- When compared to positive pressure, patients frequently prefer…
A
- The goal of oral appliance therapy (OAP)
- To modify the position of the mandible and the tongue in order to increase the upper airway size and favorably affect collapsibility
- Second line therapy for OSAH because…
- Effective treatment requires multiple adjustments that require weeks to months to accomplish
- Treatment is not 100% effective
- Objective adherence cannot be measured
- Effectiveness of OAP
- Subjective sleepiness and sleep disordered breathing are favorably impacted
- There’s a favorable effect on blood pressure
- When compared to positive pressure, patients frequently prefer…
- OAP to CPAP/BPAP
17
Q
Oral appliance therapy
- Tongue retaining devices (TRD)
- Mechanism
- Can be used in…
- Many patients are bothered by…
- Mandibular advancement devices (MAD)
- Pros
- Cons
- Optimal therapy is achieved…
- Patients who respond best
A
- Tongue retaining devices (TRD)
- Apply suction to the anterior portion of the tongue to maintain tongue protrusion and increase in the retrolingual airway
- A degree of downward rotation of the mandible is achieved
- Can be used in edentulous patients
- Many patients are bothered by the bulk of the TRDs, which negatively impacts adherance
- Apply suction to the anterior portion of the tongue to maintain tongue protrusion and increase in the retrolingual airway
- Mandibular advancement devices (MAD)
- Adjustable MADs are more comfortable and generally yield better results than nonadjustable “boil and bite” appliances
- Sequential adjustment requires weeks to accomplish and as a result, limits the utility of MADs in severe OSAH that requires expeditious treatment
- Optimal therapy is achieved in approximately one third of subjects
- Patients who respond best are those with mild OSAH, supine-dependent OSAH, and snoring
18
Q
Oral appliance therapy
- Contraindications and complications associated with MAD treatment
- Side effects
- Common side effects
- Other information about MADs
A
- Contraindications and complications associated with MAD treatment
- Insufficient tooth number
- Substantial tooth mobility
- Untreated periodontal disease
- Active temporomandibular joint syndrome
- Side effects
- Usually mild and infrequently require intervention
- Common side effects
- Mucosal dryness
- Tooth discomfort
- Hypersalivation
- Other information about MADs
- MADs are known to change occlusion over time
- Regular dental follow-up is mandatory in patients using these devices long term
