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30 Cards in this Set
- Front
- Back
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Definition of OSA:
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-Cessation of airflow for more than 10sec despite ventilatory effort 5 or more times/hr sleep
-usually associated with a decrease in SaO2>4% -pts have daytime fatigue and altered cardiopulmonary & cortical function -severity is measured by # of apneas or hypoapneas that cause sleep arousal -treat if >20 events/hr |
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Cause of OSA:
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OSA is caused by closing of upper airway while asleep, uvula & soft pallet collapse on back wall of upper airway, tongue falls backward, collapsing back wall of upper airway, uvula and soft pallet form a tight blockage, effort of diaphragm, chest, and abd cause blockage to seal tighter, patient must arouse to breath
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OSA effects:
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obstruction & snoring & restlessness lead to decreased O2 and increased CO2 (myocardial ischemia & arrythmias, PHTN, RVH, HTN leads to LVH)
-arousal, daytime sleepiness, personality changes, accident prone -long term can have serious systemic pathophysiologic consequences |
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Surgery for OSA:
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-somnoplasty: radiofrequency energy reduce soft tissue in upper airway
-uvulopalatopharyngoplasty (UPPP): removes soft tissue on back of throat, palate which increases width of airway at throat opening -Mandibular maxillar advancement for facial abnormalities -nasal surgery: nasal obstruction such as deviated septum |
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Causative/risk factors OSA:
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-obesity bmi>29
-craniofacial & orofacial bony abnormalities -nasal obstruction -large tonsils -excess neck fat |
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Suspect OSA if:
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-bmi >35 (>95th percentile pediatric)
-neck >17" men, >16" women -small receding mandible, buck teeth, posterior tongue -nasal obstruction -big tonsils |
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Diagnosis of OSA:
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-presumptive clinical dx by s/s: obestity, snoring, apnea during sleep, periodic snorting, apparent arousal, daytime sleepiness or fatigue
-increased neck circumference -definitve diagnosis: sleep study with EEG, EOG, oral & nasal airflow sensors, capnography, noise, esophageal pressure, electromyography, oximetry, b/p, ekg |
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OSA at increased risk:
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cardiac or respiratory events with reintubation
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Does anesthesia make OSA worse?
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evidence yes, all agents may reduce tone of pharyngeal muscles that act to maintain airway patency, anesthetic agents may alter ventilatory responses to hypoxemia & hypercarbia
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Intubation difficulty OSA?
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-not all OSA are difficult airways, but increases risk; may develop airway obstruction; morbid obesity, redundant or excess oropharyngeal tissue, & macroglossia present airway problems; apple round hard to intubate, pear small above waist easy; as weight increases so does incidence & severity of OSA
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How obesity causes OSA:
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inverse relationship between obesity & pharyngeal area; upper airway is compressed externally; pharyngeal area is lung volume dependent and FRC is decreased in the obese; weight loss results in reduction in OSA severity
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Regional vs. general anesthesia in OSA
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type of surgery rather than type of anesthesia; patients with OSA may have alpha & beta receptors that my not respond as expected to vasoactive drugs
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Do invasive monitors help in OSA patients?
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no evidence that more is better, monitor for MI & rhythm disturbances b/c risk of CAD, if morbidly obese a-line or vasotrac prn
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Postop Pain in OSA
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no studies to guide analgesic therapy; sedation & narcotic analgesic may worsen OSA; NSAIDS may be helpful, LA infiltration or continuous infusion of LA; observation necessary
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Postop observation:
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Consider: residual volatile agent, need for analgesia, difficult airwa, comorbidites;
-Use of O2 reduces # of desaturations & may prevent MI and arrhythmias -Use of O2 may reduce frequency of apneic episodes but doesn't affect duration -O2 could delay recognition of apneic episode |
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Postop Narcotics in OSA:
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increase in # of episodes; inhibits arousals that occur during sleep; central depressant drugs diminish action of pharyngeal dilator muscles in adult obese OSA patients theby promoting pharyngeal collapse around a fat laden pharynx; arousal response is depressed and severity of OSA will increase with admin of narcotics & sedatives
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Surgery Center candidate OSA
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minor procedure that does not require long-acting opioids; patients who will be alert after surgery & willing and able to use CPAP machine at home
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Inapproprate for sugery center OSA
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if specialized airway management may be necessary; mechanical ventilator; immediate availability of CXR, EKG, a-line, CVP;
SaO2<60%, bradycardia followed by increase in ectopy makes patient vulnerable to nocturnal angina, MI which requires higher level of care; monitor for 3 hours longer than if no OSA; monitor 7 hours longer if episode of hyposxemia or obstruction |
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Why treat OSA as inpatients:
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narcotics/sedatives casue a decrease in arousal response & can resp. arrest; central depressant drugs diminish action of pharyngeal dilator muscles promoting pharyngeal collapse, obese patients have heavy chest walls & small lungs = desaturate; HTN or biventricular hypertrophy; nocturnal angina, MI< arrhythmia from hypoxemia
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Intubation considerations OSA:
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awake-proper preparation
asleep-adequate preoxy with tight mask fit for 3-5min, 4 deep breaths in 30sec not adequate |
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Following surgery OSA
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extubate fully awake or leave intubated, fully awake: muscle relaxants fully reversed, semi-upright postion, clearly responsive; be ready for 2 person mask ventilation; observational intermediate care units; regional analgesia; CPAP if patient was on it at home
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CPAP
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nasal CPAP contain a fan that blows air under pressure into nostrils; flow generators develop constant, controllable pressure to keep upper airway open; CPAP holds soft tissue of uvula and soft palate and soft pharyngeal tissue in upper airway in position so airway remains open during sleep
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No immediate post-extubation CPAP
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impairs access for suction, deal with PONV; impairs communication; impairs monitoring facial color & LOC< fit of mask may change from postop edema; CPAP treatment for natural sleep not drug induced sleep
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Severity of OSA based on #apnea/hypopneas per hour:
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Adult: 6-20 mild OSA score 1
Peds: 1-5 mild OSA score 1 Adult: 21-40 moderate score 2 Peds: 6-10 moderate score 2 Adult: >21 severe score 3 Peds: >10 severy score 3 |
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Invasiveness of sugery and anesthesia OSA
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superficial/local/0
superficial/MAC or reg/1 superficial/GA/2 major/GA/3 |
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Opioid Requirement OSA
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none-0
low dose oral-1 high dose oral-2 parental or neuroaxial-3 |
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Determination of perioperative risk OSA:
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OSA severity (1-3) plus either invasivness of surgery (1-3) or postop opioids (1-3) which ever score is higher:
4=increased risk >5=significantly increased risk |
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Periop Management of OSA for risk =4 in ambulatory care center:
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emergency difficult airway equipment available; respiratrory care rx (nebulizers, CPAP, ventilator); portable CXR; clinical lab for ABG's, lytes, H/H; transfer in place if at ambulatory center; ***NO outpatient surgery for UPPP, tonsilectomy <3 years or upper abdominal laparoscopy
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Periop Risk=>5 OSA
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not good candidate for surgery in free standing outpatient facility; no outpatient surgery
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Dr. Benumof's Recommendations for OSA:
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recognize a presumptive clinical dix of OSA and get proper workup; decide if outpatient candidate; create appropriate monitored care for OSA, continuous SpO2 in ICU or telemetry decreases risk for OSA 4
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