OPHTHALMIC ANESTHESIA PERSPECTIVES
From the 20th Annual Scientific Meeting of the Ophthalmic Anesthesia Society, jointly sponsored by the
Cleveland Clinic Foundation Center for Continuing Education and the Ophthalmic Anesthesia Society
| OBSTRUCTIVE SLEEP APNEA —Howard D. Palte, MB, ChB, Assistant Professor of Anesthesiology, Bascom Palmer
Eye Institute, University of Miami Miller School of Medicine, Miami, FL
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| Definition: condition characterized by repetitive obstruction of upper airway; results in markedly reduced or absent airflow;
encompasses 2 main conditions, 1) central sleep apnea and 2) obstructive sleep apnea (OSA)
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| Central sleep apnea: decreased ventilatory drive (brainstem fails to send messages to periphery); may result from drugs
used intraoperatively, cardiovascular problems (eg, stroke), or toxins; results in apnea; ultimately resolved by compensatory
hyperventilation (if offending agent removed)
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| Obstructive sleep apnea: results from upper airway collapse; leads to diminution of airflow and compensatory increased
effort in periphery (chest wall and diaphragm); most common in men, 40 to 59 yr of age; in 1993, Wisconsin Cohort
Study of working adults in United States found 24% incidence of OSA in men and 9% incidence in women; when
looking at severe parameters (eg, daytime somnolence), investigators found incidence decreased to 4% in men and 2% in
women
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| Pathophysiology: under normal awake conditions, marked sustained rhythmic activation of central nervous system
(CNS) sends messages to periphery and maintains patency of airway; during sleep, normal reduction in degree of neuromuscular
junction activation, coupled with anatomic abnormality of upper airway (eg, macroglossia, low-riding or incompetent
soft palate, increased amount of parapharyngeal tissue), can easily produce OSA; in normal patient, upper
airway remains patent during sleep because of rhythmic contraction of pharyngeal dilator and abductor muscles; in patient
with OSA, airway collapses because of lack of rhythmic contraction; compensatory activation of diaphragm and intercostal
muscles attempts to overcome collapse; generates significant negative pressure; worsens degree of airway
closure; when airway lost, first response hypercapnia, with secondary hypoxia; results in CNS arousal and adrenergic response;
ultimately results in pharyngeal dilation and reestablishment of patent airway; in supine sleep position, tongue
moves to retro position and soft palate becomes incompetent, leading to almost complete occlusion of oropharynx (central
component in pathophysiology of OSA); ≈80% of patients who have OSA unaware of condition; study of elderly patients
(>65 yr of age) in assisted-living residences found 62% suffered some degree of sleep apnea; other authors found
that because of increased awareness of sleep apnea within community, case reporting and incidence reporting increased
12-fold from 1990 to 1998
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| Risk factors: obesity—number one risk in adults; increase of 1 SD in body mass index (BMI; normal range 18-25) increases
chance of developing OSA 4.5-fold; increasing body mass by 10% from standard for age group increases chance
of developing OSA 6-fold; neck circumference another useful preoperative screening test (man with shirt collar size >17
in may be at risk for OSA); patient with truncal obesity more prone to develop OSA; predominance in men (3:1 ratio,
men to women); craniofacial abnormalities—exacerbate and can be contributing factor in small minority of patients;
smoking—tobacco smokers have 3-fold increased risk of developing OSA; nasal congestion or history of severe nasal
allergies—also predisposes to OSA, probably through automatic collapse of nasopharynx; in children, structural abnormalities
(particularly hypertrophy of tonsil–adenoid complex [genetic predisposition]) tend to produce OSA; study of
postmenopausal women not receiving hormone replacement therapy found 4-fold increase in incidence of OSA; craniofacial
abnormalities in children (eg, Pierre Robin syndrome, Crouzon’s disease, retrognathia, tonsillar hypertrophy, nasal
obstruction) can also cause OSA
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| Diagnosis of OSA: clinical suspicion necessary; know which patients likely to develop condition; early detection in preoperative
clinic makes significant impact on perioperative course; polysomnography best method for diagnosis; other
proposed noninvasive or ambulatory techniques include overnight pulse oximetry and pulse transit time (PTT); abnormal
sleeping events—variant patterns of breathing (apnea and hypopnea [≥30% reduction in airflow lasting for ≥10
sec]); apnea-hypopnea index (AHI) summation of these episodes and calculation of frequency of occurences in 1 hr of
normal sleep; ≥5 episodes in any hour of sleep, plus evidence of daytime dysfunction, equals confirmatory diagnosis of
OSA; frequently categorized as mild (AHI 5-15), moderate (AHI 15-30), or severe (AHI >30)
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| Typical apneic period: patient has diminished airflow; as airflow ceases, apneic phase occurs; pulse oximetry provides
delayed data about OSA and its untoward effects; nasopharyngoscopy shows edema and increased mass of parapharyngeal
tissue; patient typically sleeps away from other family members, does not sleep well at night (no REM sleep), has
daytime somnolence, ultimately becomes grouchy and upset (personality changes, behavior becomes unruly and unacceptable),
has impaired cognition, and more likely to be involved in motor vehicle accident; as patient ages, BMI likely to
increase into abnormal range; in younger patient, incidence of continuous snoring related to adenotonsillar hypertrophy;
once adenoidal complex shrinks, patient relatively symptom-free; symptoms then reappear in 40-yr age group, initially
with intermittent snoring, followed by more severe apnea, hypersomnolence, and eventually OSA; focus should be on detection
in patients in 25- to 35-yr age group who have some degree of sleep apnea but minimal symptomatology
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| History and physical examination: focus on obesity, hypertension, snoring (ask spouse, not patient), and daytime
somnolence; incidence of sleep apnea low if collar size <17 in circumference, but high if ≥19 in; 40% of patients develop
hypertension; presence of sleep apnea increases risk of developing hypertension, as single variant, by 3-fold; incidence
of ischemic heart disease ≈5-fold higher; in patient with >10 apneic spells in 1 hr, or whose polysomnography
indicates drops in saturation to <60%, >50% will have arrhythmias and concomitant myocardial ischemia; snoring results
in 3-fold increased risk of developing cerebrovascular accident; risk increased 8-fold with documented apnea;
sleep apnea also has inflammatory response, with activation of neutrophil superoxide and increased platelet aggregation
(major determinants in endothelial damage and progression of atherosclerotic disease); patients with OSA have
cognitive function equivalent to that of person 5 yr older; patient with >15 apneic episodes per hour essentially 50%
sedated; also at increased risk for asthma and development of pulmonary hypertension
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| Perioperative management: conservative measures best, eg, weight reduction, sleep hygiene (particularly avoiding
supine position); adjunctive measures include avoidance of nocturnal use of alcohol and use of oral and nasal appliances;
in cases where conservative therapy not effective, or when anatomic abnormality present, orthognathic surgery of maxilla
and mandible may be necessary; dental devices used to maintain oropharyngeal patency through changing tongue position
or to maintain patency of soft palate; nasal nocturnal continuous positive airway pressure (CPAP) most definitive
treatment available; increasing pressure delivered to upper airway improves quality and diameter of upper airway; nasal
CPAP tolerated at best for 6 hr/night; minor side effects include nasal congestion and conjunctivitis; high failure rate
(50%); modifications include automatic titration of CPAP or alternative pressure delivery (BiPAP); 6 wk of CPAP therapy
can reverse hypertensive changes and improve cardiac function; disadvantages include barotrauma, conjunctivitis,
skin breakdown, and high failure rate
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| Sleep apnea and eye surgery: OSA can cause changes in eyelid tissue (eg, “floppy eyelid syndrome”) and optic nerve
(eg, nonarteritic anterior ischemic optic neuropathy, glaucoma); associations include Marfan syndrome (dislocation of
lens) or keratoconus (bulging or enlargement of corneal layer)
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| Perioperative anesthesia evaluation: in preoperative evaluation, obtain history, assess severity, look for associated
disorders, and determine whether surgery can be postponed (especially if general anesthesia necessary); all anesthetic
agents depressants and cause diminution of pharyngeal dilatation; narcotics can lead to further airway obstruction by inhibiting
central response to hypoxia and hypercarbia; when using regional anesthesia, use minimal or no sedation, stay in
contact with patient, maintain airway patency, and have senior anesthesia provider present who is adept at regional anesthesia;
prolonged observation in postanesthesia care unit necessary with any degree of sedation; obese patients always at
risk for intubation difficulties (rapidly desaturate); important to educate patient about anesthesia plan, speak with surgeon
about problems and need for special considerations, and alert operating room (OR) personnel that case may be airway
management issue and technique slightly different; if patient on CPAP, bring it to hospital; if used preoperatively, have it
available postoperatively; ancillary airway devices may be necessary; make arrangements for patient to have adequate
care on discharge; position carefully; airway access may be problem under drapes; plan to use little or no sedatives or
hypnotics; prepare patient and family for outcome
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| CARDIAC DISEASE —Marc Allan Feldman, MD, Head, Section of Anesthesia, Cole Eye Institute, Cleveland Clinic,
Cleveland, OH
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| Introduction: joint effort by American College of Cardiology (ACC) and American Heart Association (AHA) to develop
guidelines on perioperative evaluation and management for noncardiac surgery; first set of guidelines on topic
written in 1996; revised in 2002; available at www.americanheart.org or www.acc.org; committee included anesthesiology,
general and interventional cardiology, arrhythmology, noninvasive testing, vascular medicine, and vascular surgery
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| Guidelines: purpose of guidelines to educate and provide information and thereby assist decision-making (not policy or
regulation); describe generally acceptable approaches, but not necessarily only approaches; designed to meet needs of
most patients in most situations; ultimate judgment by physician and patient; methodology and evidence based on literature
review and judgment and experience of experts on panel (and persons contacted by experts); intended to improve
practice patterns and help individual organizations produce practice patterns; other goals of guidelines to improve efficiency
of patient care, improve financial situation (especially avoiding unnecessary testing), and help role of consultant;
overall theme of guidelines that intervention rarely needed to lower risk; preoperative evaluation not for clearance; cardiologist
or internist asked to 1) evaluate medical status of patient, 2) recommend perioperative management, and 3) provide
risk profile for decision-making; no test should be performed unless it influences patient treatment
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| Recommendations: history and physical examination should be thorough, but with particular attention to clinical markers;
helpful in determining risk category; look for coronary artery disease (eg, signs and symptoms of myocardial infarction
[MI] or angina, heart failure, symptomatic arrhythmias, pacemakers, defibrillators, orthostatic hypotension,
orthostatic intolerance), functional capacity, comorbid conditions, and surgery-specific risk
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| Predictors of increased perioperative cardiovascular risk
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 | Major: unstable coronary syndromes (eg, acute [≤7 days] or recent [≤30 days] MI, unstable or severe angina); decompensated
heart failure; significant arrhythmias (eg, high-grade atrioventricular block, symptomatic ventricular
arrhythmias with heart disease, supraventricular arrhythmias with uncontrolled rate); severe symptomatic valvular
disease
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| Angina: class I (only with severe exertion); class II (good-to-excellent exercise tolerance with exertion); class III (occurs
with daily activities); class IV (cannot perform daily activities)
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| Intermediate: mild-to-moderate angina; remote MI; compensated heart failure; creatinine >2.0 mg/dL; diabetes
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| Minor: advanced age; abnormal electrocardiography (ECG); rhythm other than sinus rhythm; low functional capacity;
history of stroke; uncontrolled systemic hypertension
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| Risk stratification for noncardiac surgical procedures
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| High: no ophthalmic cases in this category; involves large amount of tissue trauma and blood loss, eg, aortic major vascular
surgery, peripheral vascular surgery, major spine surgery, procedures with large fluid shifts, and/or major blood
loss
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| Intermediate: may include occasional eye surgeries, eg, orbital exenteration (involves eye muscles and periosteum of orbit);
procedures 1 to 2 hr in length; procedures associated with 1 to 2 U of blood loss
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| Low: most other surgeries (eg, vitreoretinal procedures, cataract surgery)
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| Preoperative evaluation: determine degree of urgency and degree of stress of procedure; more urgent procedure gets
less noninvasive testing; less stressful procedures require less noninvasive testing; cataract extraction least urgent procedure
(except in neonate); acute retinal detachment and open globe injuries more urgent; orbital tumors, exenteration,
and enucleation highest stress procedures; muscle procedures and cataract surgery lowest stress
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| Process: identify need for noncardiac surgery; if urgent, go directly to OR (risk stratification later); if revascularized in
previous 5 yr or assessed by cardiologist in previous 2 yr, ask about clinical predictors; with minor and intermediate
clinical risk predictors, proceed to OR; with major clinical predictors, likely to have difficulties with or without surgery;
patient scheduled for major surgery who has intermediate risk predictors and low functional capacity may need
referral; noninvasive testing that shows large areas of ischemia or other problem requires follow-up; if scheduled for
cataract anesthesia and surgery, determine if major risk predictors present; appears reasonable to wait 4 to 6 wk after
MI to perform elective surgery; stage 3 hypertension (systolic blood pressure [BP] >180 mm Hg, diastolic >110 mm
Hg) should be controlled before starting surgery (over several days to weeks, not minutes); continuation of treatment
through perioperative period critical; speaker recommends patient with high BP scheduled for cataract surgery be
treated and managed by personal physician or referred before scheduling surgery; patient with valvular heart disease
(stenotic lesions higher risk; regurgitant valves generally lower risk) who walks can probably be treated medically
“and have anything definitive later”; asymptomatic nonsustained ventricular tachycardia not shown to increase risk in
perioperative period; patient not pacemaker-dependent at low risk; in optimal circumstances, know type of device,
evaluate before and after surgery, determine underlying rhythm, interrogate for settings and battery status, turn off rate-
responsive mode, and turn off implanted cardioverter/defibrillator before surgery (and back on after surgery); noninvasive
left ventricular function testing should be performed in patient with uncontrolled heart failure; 12-lead ECG with
recent chest pain or ischemia (class IIb recommendation, except in cataract surgery [class III]); use β blockers for patients
already taking for hypertension and for those at risk for ischemia
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Suggested Reading
Abdal H et al: The eye in sleep apnea syndrome. Sleep Med 7:107, 2006; Backer CL et al: Myocardial reinfarction
following local anesthesia for ophthalmic surgery. Anesth Analg 59:257, 1980; Bass EB et al: Do ophthalmologists, anesthesiologists,
and internists agree about preoperative testing in healthy patients undergoing cataract surgery? Arch Ophthalmol
113:1248, 1995; Erdem CZ et al: Doppler measurement of blood flow velocities in extraocular orbital vessels
in patients with obstructive sleep apnea syndrome. J Clin Ultrasound 31:250, 2003; Finn L et al: Sleep-disordered
breathing and self-reported general health status in the Wisconsin Sleep Cohort Study. Sleep 21:701, 1998; Launois SH
et al: Sleep apnea in the elderly: a specific entity? Sleep Med Rev 11:87, 2007; Young T et al: The occurrence of sleep-
disordered breathing among middle-aged adults. N Engl J Med 328:1230, 1993.
Educational Objectives
| The goal of this program is to improve anesthetic management of patients with obstructive sleep apnea (OSA) and of those
with cardiac disease scheduled for ophthalmic surgery. After hearing and assimilating this program, the participant will be
better able to:
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| 1. Define OSA and describe its pathophysiology.
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| 2. Identify risk factors of OSA in patients who likely have the syndrome.
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| 3. Confirm the diagnosis of OSA and discuss treatment options available to primary and secondary health providers.
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| 4. Formulate an effective perioperative anesthesia plan to optimally manage patients through pre-, intra-, and postoperative
phases and assist in preparation of hospital protocols for management of OSA.
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| 5. Review established guidelines on the perioperative evaluation and management of cardiac disease for noncardiac
surgery, and discuss the recommendations and risks associated with ophthalmic anesthesia and surgery.
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Faculty Disclosure
In adherence to ACCME Standards for Commercial Support, Audio-Digest requires all faculty members to disclose relevant
financial relationships within the past 12 months that might create any personal conflicts of interest. Any identified conflicts
were resolved to ensure that this educational activity promotes quality in health care and not a proprietary business or commercial
interest. For this program, the faculty reported nothing to disclose.
Acknowledgements
Drs. Palte and Feldman spoke at the 20th Annual Scientific Meeting of the Ophthalmic Anesthesia Society, held October
13-15, 2006, in Chicago, IL, and jointly sponsored by the Cleveland Clinic Foundation Center for Continuing Education
and the Ophthalmic Anesthesia Society. The Audio-Digest Foundation thanks the speakers and the sponsors for their cooperation
in the production of this program.
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