disorders of ventilation and sleep apnea Flashcards
(29 cards)
1
Q
What is primary alveolar hypoventilation? (Odine’s curse)
A
- rare
- inadequate alveolar ventilation: normal neuro function, airways, lungs, chest wall and ventilatory muscles
- hypoventilation is worse during sleep
- etiology is congenital or severe trauma/insult to the brainstem
2
Q
Pt profile of primary alveolar hypoventilation?
A
- usually non-obese
- males in 30s or 40s
- present with lethargy, HA and somnolence
PE:
no dyspnea, cyanosis, and evidence of pulmonary HTN (shunting of blood)
3
Q
dx workup of hypoventilation?
A
- labs (chem, TSH, CBC, ABG)
- CXR (rule out lung disease)
- brain imaging CT/MRI (rule out stroke, tumor)
- echo: right heart changes from chronic hypoxemia
- PFTs: can include negative inspiratory pressure to rule out neuromuscular disease
- muscle stim. tests/nerve conduction velocity to rule out neuromuscular disease
4
Q
Tx of primary alveolar hypoventilation?
A
- supp oxygen
- positive pressure ventilation
- respiratory stimulants (not that effective): medroxyprogesterone, acetazolamide, theophylline
- diaphragm pacing with phrenic nerve stimulation
5
Q
What is Pickwickian syndrome?
A
- blunted ventilatory drive and increased mechanical load imposed upon the chest by obesity
- voluntary hyperventilation returns the PCO2 and PO2 toward normal values
- most likely also have obstructive sleep apnea
6
Q
Tx of pickwickian syndrome?
A
- wt loss
- NPPV (noninvasive positive pressure ventilation) - Bipap or CPAP
- tracheostomy
- respiratory stimulants (not primary tx) - theophylline or acetazolmide (works in babies but otherwise not effective)
7
Q
What is hyperventilation and what are the causes?
A
- increase in alveolar ventilation that leads to decreased CO2
- causes:
brainstem injury (comp. mechanism overshooting)
pregnancy
hypoxemia
lung diseases (that cause hypoxia)
sepsis
liver failure
fever
pain
anxiety
hyperthyroidism
8
Q
Signs and sxs of acute hyperventilation?
A
- rapid RR
- paresthesias
- carpopedal spasm
- tetany
- anxiety
- arrhythmias
- cerebral vasoconstriction and cerebral ischemia
- seizures
9
Q
Tx of acute hyperventilation?
A
- tx underlying cause
- pursed lip breathing or
- rebreathing expired gas from paper bag
- anxiolytic drugs
10
Q
Sxs of chronic hyperventilation?
A
- nonspecific sxs that can be reproduced by voluntary hyperventilation: fatigue dyspnea anxiety palpitations dizziness
11
Q
What is the most common sleep related breathing disorder?
A
- sleep apnea
- 20-30% males
- 10-15% females
- more common in young (less than 35) African americans compared to caucasians of the same age, independent of body weight
- prevalence in Asia similar to US despite lower rates of obesity (genetic and ethnic component)
- people with certain chin and jaw structure more at risk for sleep apnea, down syndrome (larger tongues) - anything that obstructs the airway - tonsils, tongue, soft palate (lose muscle tone while asleep - blocked airway)
12
Q
What occurs in sleep apnea to cause obstruction of the airway?
A
- caused by recurrent collapse of pharyngeal airway during sleep
- cessation of airflow
- disturbances in gas exchange, and poor sleep quality (reduced REM sleep)
13
Q
What are RFs for sleep apnea?
A
- obesity
- advancing age
- smoking
- craniofacial or upper airway soft tissue abnormalities
- nasal congestion
- pregnancy
- end stage renal disease
- CHF
- chronic lung disease
- family hx
- menopause
- hypothyroidism
14
Q
Pt factors that are associated with high likelihood of sleep apnea?
A
- neck circumference greater than 43 cm (17 inch) in men and 37 cm (15 inches) in women
- narrowing of lateral airway walls, which is an independent predictor in men but not women
- enlarged kissing tonsils (3+ to 4+)
15
Q
WHat are the signs and sxs that are suspicious for sleep apnea?
A
- HTN: difficult to control
- excessive daytime somnolence
- morning sluggishness
- AM HAs
- daytime fatigue
- cognitive impairment
- impotence
- obesity
- loud snoring
- witnessed apneas
- nocturnal restlessness
- personality changes
- poor judgement
- depression
- memory impairment
- falling asleep while driving or in waiting room
16
Q
What are 3 vascular disease features of OSA?
A
- CVD
- cerebrovascular disease
- cardiac dysrhythmias
- high correlation with A fib
- promotes thrombosis
17
Q
Complications of OSA?
A
- motor vehicle crashes (2-3 x more common)
- higher users of medical resources: insulin resistance, DM, metabolic syndrome
- CVD: HTN, Pulm HTN, CAD, arrhythmias, CHF, CVA
- increased risk of perioperative complications
- 2-3x increased risk of all cause mortality (untx severe sleep apnea)
18
Q
Links b/t OSA and metabolic syndrome?
A
- obesity
- HTN
- insulin resistance
- proinflammatory/oxidative stress = prothrombotic state
- hyperlipidemia
19
Q
What questions should you ask about OSA?
A
- tired during the day?
- ever fall asleep while driving?
- Fall asleep reading, watching TV or watching a movie?
- Do you ever fall asleep at work?
- If you are sitting quietly at home are you likely to fall asleep if you are not actively engaged in something?
- Do you snore?
- If yes to snoring, is it so loud that it is bothersome to others?
20
Q
How can we quantify sxs of sleepiness?
A
- EDS: excessive daytime sleepiness: most frequently assessed by a sleep physician using the epworth sleepiness scale - want to see improvement after tx
- questionnaire is used to help determine how frequently the pt is likely to doze off in 8 frequently encountered situations
- useful for evaluating responses to tx, ESS score should decrease with effective tx
21
Q
Dx OSA?
A
- lab tests: TSH, RBC (polycythemia?? - will see in severe desats during night time)
- polysomnography
- home testing available for screening purposes
- home overnight oximetry testing: has high negative predictive value for sleep apnea when normal
22
Q
Definition of Apnea? Hypopnea?
A
- apnea: breath cessation for at least 10 seconds with decrease in O2 sats
- hypopnea: decreased airflow with a drop in O2 sat of at least 4%
23
Q
WHat is the Apnea-hypopnea index (AHI), what is the Respiratory disturbance index (RDI)?
A
- AHI: number of combined events per hour
- RDI: number of apneas, hypopneas, and respiratory effort related arousals per hour of sleep
24
Q
What does a polysomnography (sleep study) record?
A
- EEG: stage of sleep
- electro-oculography - muscle tension and movement of eye (REM)
- EMG: muscle on face (tone lessens as pt falls asleep)
- EKG
- pulse ox
- Respiratory effort: is it occurring or no - central sleep apnea?
- airflow: this should correlate with respiratory effort
25
What is the RDI values?
- mild sleep apnea: 5-14/hr
- moderate: 15-29
- severe: 30 or greater
26
Tx of OSA?
- wt loss
- sleep positioning
- avoidance of resp suppressants like ETOH, and narcotics
- CPAP (main tx) ***
- BiPAP: used for pts that have degree of central sleep apnea, has back up rate
- oral (dental) appliances
- surgery: uvulopalatophyaryngoplasty (UPPP) - take tissue out of pharynx and reconstruct soft palate
27
What is the difference b/t CPAP and BiPAP?
- CPAP: continuous positive airway pressure, std tx for OSA
- BiPAP: bilevel positive airway pressure. non-invasive positive pressure ventilation, for use when taking a deep breath is difficult. Lower pressure for exhalation and higher pressure for inhalation. Can have back up rate to augment RR. Used for mixed (obstructive and central) sleep apnea and also for impending respiratory failure
28
What is central sleep apnea?
- most often seen mixed with OSA
- no ventilatory effort seen during episodes of apnea as determined during polysomnogram
- brain forgets to tell body to breathe
- can be seen in premature babies
- clinically common in post stroke, TBI, and CHF
29
What conditions may be associated wih CSA?
- CHF
- hypothyroid disease
- kidney failure
- neuro diseases: parkinson's, alzheimers. and amyotrophic lateral sclerosis
- damage to brainstem caused by encephalitis, stroke, injury or other factors
