ANESTHETIC DELIVERY AND TECHNIQUE
| ANESTHETIC DELIVERY: I CAN’T BELIEVE THEY’RE PUSHING PROPOFOL?!? —Jeffrey L. Apfelbaum,
MD, President, American Society of Anesthesiologists, and Professor and Chair, Department of Anesthesia and Critical
Care, University of Chicago Pritzker School of Medicine, Chicago, IL
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| Introduction: trends—propofol increasingly administered by clinicians other than anesthesiologists, certified registered
nurse anesthetists (CRNAs), and anesthesiology assistants; increasing use of propofol outside of intensive
care unit (ICU); Oregon only state that has rules promulgated by State Board of Nursing permitting registered
nurses to administer propofol as part of sedation routine; gastroenterologists have developed nurse-administered
propofol sedation (NAPS) procedures
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| Continuum of sedation: initially defined by American Society of Anesthesiologists (ASA) in 1998, then adopted
by Joint Commission on Accreditation of Healthcare Organizations
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 | Minimal: drug-induced state during which patients respond normally to verbal commands; cognitive function and
coordination may be impaired; ventilatory and cardiovascular functions unaffected; can be achieved with anxiolytic
agent (eg, benzodiazepine administered po)
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| Moderate: drug-induced depression of consciousness during which patients respond purposefully to verbal commands
(alone or accompanied by light tactile stimulation); no interventions required to maintain patent airway;
spontaneous ventilation adequate; cardiovascular function usually maintained; purposeful response to verbal
stimulation defined as appropriate cognitive response to questioning; purposeful response to tactile stimulation
requires more than withdrawal from pain
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| Deep: drug-induced depression of consciousness during which patient not easily aroused but responds purposefully
following repeated or painful stimulation; ability to independently maintain ventilatory function may be impaired;
may require assistance in maintaining patent airway; spontaneous ventilation may be inadequate; cardiovascular
function usually maintained; note—predicting patient’s response to sedation often difficult;
practitioners should be able to rescue patient when level of sedation becomes deeper than initially intended
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| General: drug-induced loss of consciousness; no arousal, even by painful stimulation; spontaneous ventilation frequently
inadequate; cardiovascular function may be impaired
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| Hazards of NAPS: gastroenterology literature cites evidence for safety; small study (Ramsey et al, 2004) of NAPS
for endoscopic gastrointestinal (GI) procedures followed protocol established by gastroenterologists; brain function
monitored; 74% of patients reached levels of general anesthesia (moderate anesthesia intended); study (Blouin et
al, 1993) looked at hypoxic ventilatory response during conscious sedation and isohypercapnia in 8 healthy volunteers;
propofol given for induction and as infusion; blood levels of propofol reached 2.2 µg/mL, level associated
with profound (>80%) depression of hypoxic ventilatory response; Church et al looked at computer-controlled propofol
sedation during endoscopy; to insert endoscope without difficulty, blood level of 2.5 µg/mL necessary;
Vargo et al looked at gastroenterologist-administered propofol sedation (GAPS) in 10 patients; apnea detected in 6
patients, but “no serious sequelae”; Ramsey et al conducted prospective blinded study examining sedation levels in
40 patients using standard ASA monitors; depth of sedation and transcutaneous CO2 measured; Ramsey sedation
scores assigned to all patients; 100% of patients achieved general anesthesia at some point during procedure; 45%
had PCO 2 >45 mm Hg, but O2 desaturation rare; 70% of patients required airway intervention; O2 saturation averaged
97% and was not trigger for intervention
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| Concerns: deaths associated with propofol sedation have been reported; some researchers suggest publication bias
within gastroenterology literature (controversial); questions about informed consent (patient may not know who is
administering sedation or general anesthesia); Wilcox quote from American Journal of Gastroenterology in 2004
states, “While most, but not all, studies suggest less recall for the endoscopic procedure and more patient satisfaction
with propofol as compared to a standard narcotic/benzodiazepine sedation, my hunch is that most patients, when presented
with the real risk from using propofol by those who do not have a public track record would undoubtedly
choose to have more recall for the procedure, more discomfort and a slower return to normal mental function than
the potential alternative Safety must always be a primary concern”
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| Recent study: large multi-site cohort study looked at risk factors for cardiopulmonary events during propofol-mediated
upper endoscopy and colonoscopy; measured outcomes included dysrhythmia, decreases in O2 saturation,
prolonged hypoxemia, respiratory distress, tachycardia, tracheal compression, transient hypoxemia, vasovagal reaction,
and wheezing; results—upper GI procedures and colonoscopy associated with ≥1% risk for cardiopulmonary
event; overall risk significantly higher when propofol administered by gastroenterologist, compared to
anesthesia professional
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| Future: patient-controlled sedation with propofol; computer-controlled sedation; fospropofol (Aquavan; in development;
quickly metabolized into propofol after administration; has faster onset and longer duration of action)
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| ANESTHETIC TECHNIQUE: WHAT MODIFICATIONS ARE REALLY INDICATED IN THE ELDERLY? —
Jacqueline M. Leung, MD, MPH, Professor of Anesthesiology, Department of Anesthesia and Perioperative Care,
University of California, San Francisco, School of Medicine
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| Introduction: US population aging; ≈20% of US population will be ≥65 yr of age by 2025; elderly undergo more
surgical and anesthetic procedures than younger patients (one-third of all surgeries); ≈50% of patients ≥65 yr of age
have some type of surgery during lifetime
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| Aging and adverse events: advances in anesthesia and minimally invasive surgery have led to increased number of
surgical procedures performed among elderly and sick patients; speaker’s study of elderly patients undergoing major
surgery found that adverse events occurred in ≈20% of patients ≥70 yr of age and in ≈25% of patients ≥80 yr of age;
cardiac, neurologic, and pulmonary adverse events most common
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| Preoperative hypertension: history of hypertension (eg, chronic, untreated, or caused by withdrawal from medications)
important; population studies show hypertension increases risk for cardiac and cerebrovascular disease; stage 3
hypertension (systolic BP >180 mm Hg; diastolic BP >110 mm Hg) increases end-organ damage; anesthesia provider
must consider increased perioperative risk for cardiac events; meta-analysis found little evidence of perioperative risk
for cardiac complications if systolic BP <180 mm Hg or diastolic BP <110 mm Hg at admission; risk unclear among patients
with higher BPs; major adverse events include ischemia, arrhythmias, and cardiovascular lability; no evidence that
deferring anesthesia and surgery reduces perioperative risk; preoperative BP control—important to assess baseline BP
for each patient; if BP consistently elevated, attempt to optimize; unknown whether lowering BP several days prior to
surgery has benefit over acute titration immediately before anesthetic induction; speaker does not regularly postpone urgent
surgery; if BP >180/110 mm Hg, more invasive intraoperative monitoring recommended, and postoperative monitoring
should occur in intensive care unit (ICU)
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| Cardiac risk assessment: major predictors of cardiovascular risk—unstable coronary syndromes; decompensated
congestive heart failure (CHF) or active CHF; significant arrhythmias; severe valvular disease; intermediate
predictors—stable angina; history of myocardial infarction (MI); compensated CHF; diabetes; renal insufficiency;
minor predictors—advanced age; abnormal electrocardiography (ECG); rhythm other than sinus; low functional
capacity; history of stroke; uncontrolled hypertension
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| Management algorithms: assess need for noncardiac surgery; if urgent, proceed; if urgent-elective, ask about coronary
revascularization in previous 5 yr; if yes, ask about recurrent symptoms; predictors of major risk present—
postpone surgery; address risk factors; predictors of intermediate risk present—assess functional capacity (ability to
carry out activities of >4 metabolic equivalents [METs], eg, sustained brisk walking on treadmill; functional capacity
<4 METs considered poor [consider noninvasive testing]); caveat—chronic pain may limit functional capacity;
functional limitation may have other noncardiac causes (eg, physical deconditioning, obesity, or chronic obstructive
pulmonary disease [COPD]) rather than primary cardiac etiology; predictors of minor risk present—proceed to
surgery if patient has good functional capacity or if patient has poor functional capacity but procedure associated
with low or intermediate risk; consider delaying high-risk surgery (instead, perform additional tests) in patients
with poor functional capacity; limitations of algorithm—does not specify how to treat patients with >1 minor risk
predictor; has limited use in older patients
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| Preoperative risk stratification: underlying assumption that identifiable risks can be modified; cardiac surgery
(eg, coronary artery bypass graft [CABG]) or other interventions to modify cardiac risk factors also associated with
risk (must be added to risk associated with noncardiac surgery); preoperative optimization of coexisting disease
(eg, hypertension, diabetes, angina, COPD) important; conclusion—risk stratification important, but use of algorithm
would lead to increased number of noninvasive procedures among elderly patients because of poor functional
status
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| Perioperative β-blockade: ischemia prophylaxis (achieved by multiple classes of drugs, including nitrates, β-
blockers, calcium channel blockers, and α2 -agonists); mechanism of action—inhibits stimulation by catecholamines,
resulting in reduced heart rate (HR) and contractility; reduces ischemia by decreasing myocardial O2 consumption
(MVO 2 ), primarily by decreasing HR, contractility, and wall tension; timing of administration—
speaker’s institution implements prophylactic β-blockade preoperatively; intraoperative period associated with
lowest risk, if HR and BP controlled; focus should be on postoperative period; Auerbach and Goldman recommendations
for perioperative β-blockade—patients with ≥2 moderate-risk factors (age ≥65 yr; hypertension; current
smoker; hypercholesterolemia; non-insulin–dependent diabetes); patients with ≥1 high-risk factors (history of ischemic
heart disease; history of stroke or transient ischemic attack [TIA]; insulin-dependent diabetes; chronic renal
insufficiency); patients undergoing high-risk surgeries (eg, peritoneal, intrathoracic, and suprainguinal
vascular); types of β-blockers—atenolol (50-100 mg po daily) and metoprolol (25-50 mg po bid) commonly used
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| Risk reduction: recent meta-analysis indicates routine use of β-blockers does not decrease rates of adverse outcomes
(eg, MI, mortality, length of hospital stay) in low-risk patients; study of preoperative treatment with metoprolol did
not show reduction in cardiovascular events at 30 days; retrospective review suggests perioperative β-blockade may
increase risk in low-risk patients undergoing noncardiac surgery (using Goldman revised cardiac index); paradoxic
increase in event rate may be due to withdrawal of β-blocker; another retrospective review suggests patients who receive
shorter-acting β-blockers (eg, metoprolol) have higher rate of perioperative events, compared to those who receive
longer-acting β-blockers (eg, atenolol)
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| Clinical practice: identify patients at highest risk; implement preoperative β-blocker and titrate HR prior to surgery
(usually not feasible); supplement β-blocker intraoperatively to achieve target HR; continue β-blockers postoperatively
for ≥1 wk; consider weaning off β-blocker to reduce risk for withdrawal
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| Class I indications: patients on β-blockade therapy for angina, asymptomatic arrhythmias, or hypertension (continue
antihypertensive medication to day of surgery and postoperatively; if patient unable to take oral medication
after surgery, IV β-blockers should be administered); patients undergoing vascular surgery with high cardiac risk
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| Class IIa: preoperative assessment identifies heart disease or multiple risk factors
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| Class IIb: patients with intermediate cardiac risk, including those identified as intermediate risk by preoperative
testing, and low-risk patients undergoing vascular surgery
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| Class III: contraindications to β-blockers (eg, advanced heart block, asthma or reactive airway disease, low resting
HR [eg, <60], and hypotension)
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| Congestive heart failure: major risk predictor for perioperative cardiac event; increases postoperative complications
and mortality in hospital; 2-yr survival poor with diagnosis of heart failure unrelated to surgery; one-third of
patients with history of heart failure may present with normal systolic function as measured by echocardiography;
resting ejection fraction (EF) often preserved in elderly patients
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| Diastolic heart failure: pressure-volume relationship shifts left; small changes in volume result in abnormal increases
in pressure (may result in pulmonary edema); compliance affects passive and active filling; systolic BP
increases with age, leading to increased thickness of left ventricular (LV) wall, smaller cavity, and decreased rate
of ventricular filling; aging also associated with increased myocardial fibrosis, stiffer ventricle, and hypertrophy
of left atrium; disorders associated with diastolic dysfunction—systemic hypertension; coronary artery disease;
cardiomyopathies; diabetes; chronic renal disease; aortic stenosis; atrial fibrillation; nonspecific symptoms—
exercise intolerance; dyspnea; cough; edema; fatigue
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| Preoperative assessment of diastolic dysfunction: Doppler echocardiography most common; radionuclide ventriculography
invasive (rarely used); exclusion of other clinical syndromes with similar presentation (eg, pulmonary
morbidity) important; Doppler echocardiography—elderly patients without evidence of heart disease have reversal
of ratio between peak early filling wave (E wave) and atrial filling wave (A wave); ≈50% of patients with
normal LVEF have diastolic filling abnormalities
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| Perioperative goals: maintain normal sinus rhythm; maintain low HR; control BP; optimize blood volume; detect and
treat myocardial ischemia, which may lead to acceleration or worsening of diastolic heart failure; pharmacologic
management—diuretics; calcium channel blockers; β-blockers; angiotensin-converting enzyme (ACE) inhibitors;
these agents reduce preload or afterload
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Suggested Reading
Blouin RT et al: Propofol depresses the hypoxic ventilatory response during conscious sedation and isohypercapnia.
Anesthesiology 79:1177, 1993; Church JA et al: Propofol for sedation during endoscopy: assessment of a computer-
controlled infusion system. Gastrointest Endosc 37:175, 1991; Fong HK et al: The role of postoperative analgesia in
delirium and cognitive decline in elderly patients: a systematic review. Anesth Analg 102:1255, 2006; Leung JM et al:
Pilot clinical trial of gabapentin to decrease postoperative delirium in older patients. Neurology 67:1251, 2006; Leung
JM et al: Relative importance of preoperative health status versus intraoperative factors in predicting postoperative adverse
outcomes in geriatric surgical patients. J Am Geriatr Soc 49:1080, 2001; Levine WC et al: Anesthesia for the elderly:
selected topics. Curr Opin Anaesthesiol 19:320, 2006; Phillip B et al: The prevalence of preoperative diastolic
filling abnormalities in geriatric surgical patients. Anesth Analg 97:1214, 2003; Ramsey MA et al: Nurse-administered
propofol sedation (NAPS) for gastrointestinal endoscopic procedures: NAPS or NAPA? Anesthesiology 101:A68, 2004;
Rex DK et al: Trained registered nurses/endoscopy teams can administer propofol safely for endoscopy. Gastroenterology
129:1384, 2005; Rex DK: Review article: moderate sedation for endoscopy: sedation regimens for non-anaesthesiologists.
Aliment Pharmacol Ther 24:163, 2006; Vargo JJ et al: Gastroenterologist-administered propofol for therapeutic
upper endoscopy with graphic assessment of respiratory activity: a case series. Gastrointest Endosc 52:250, 2000; Wang
Y et al: The effects of postoperative pain and its management on postoperative cognitive dysfunction. Am J Geriatr Psychiatry
15:50, 2007.
Educational Objectives
| The goals of this program are to educate anesthesia providers about the trends of propofol administration and to review
modifications of anesthetic technique indicated in the elderly. After hearing and assimilating this program, the
participant will be better able to:
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| 1. Explain the continuum of sedation and its effects on responsiveness, airway, spontaneous ventilation, and cardiovascular
function.
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| 2. Describe the hazards of nurse-administered propofol sedation.
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| 3. Identify future trends and new pharmacologic agents for sedation during surgery.
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| 4. Review the guidelines for preoperative cardiac evaluation of elderly patients presenting for noncardiac surgery.
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| 5. Examine the implications of diastolic dysfunction in the perioperative period.
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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
Dr. Apfelbaum spoke at Challenges for Clinicians, held December 1-3, 2006, in Chicago, IL, and sponsored by the University
of Chicago Pritzker School of Medicine, Department of Anesthesia and Critical Care; Dr. Leung was recorded at
the CSA/UCSD Annual Meeting and Clinical Anesthesia Update, held May 31 to June 3, 2007, in San Diego, CA, and cosponsored
by the California Society of Anesthesiologists and the University of California, San Diego, School of Medicine.
The Audio-Digest Foundation thanks the speakers and the sponsors for their cooperation in the production of this
program.
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