HOT TOPICS IN PERIOPERATIVE OUTCOMES AND PATIENT MANAGEMENT:
PART 2
Educational Objectives
| The goal of this program is to improve cognitive outcomes in elderly surgical patients by examining etiology, consequences,
and ways of reducing perioperative cognitive dysfunction. After hearing and assimilating this program, the clinician will be
better able to:
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 | 1. Critique the various types of neuropsychologic tests.
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| 2. Estimate the impact of perioperative cognitive decline on short- and long-term outcome and quality of life and identify
strategies for reducing cognitive decline.
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| 3. Discuss the impact of aging on anesthesiology.
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| 4. Assess changes related to informed consent in dealing with more cognitively impaired individuals undergoing anesthesia
and surgery.
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| 5. Provide examples of the impact of aging on anesthetic management, mainly focusing on diastolic dysfunction, temperature
regulation, and postoperative cognitive problems.
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Faculty Disclosure
In adherence to ACCME Standards for Commercial Support, Audio-Digest requires all faculty and members of the planning
committee 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 and planning committee reported nothing to disclose.
Acknowledgements
Dr. Newman spoke in New York, NY, at the 61st Annual Postgraduate Assembly in Anesthesiology, held December 7-11,
2007, and sponsored by the New York State Society of Anesthesiologists, Inc; Dr. Monk, in Toronto, ON at Anaesthetic
Practice 2007—Old Dogma or New Tricks, held November 23-25, 2007, and sponsored by the University of Toronto
Faculty of Medicine, Departments of Anaesthesia and Continuing Education. The Audio-Digest Foundation
thanks the speakers and the sponsors for their cooperation in the production of this program.
| PERIOPERATIVE COGNITIVE DYSFUNCTION —Mark F. Newman, MD, Merel H. Harmel Professor and Chair, Department
of Anesthesiology, Duke University School of Medicine, Durham, NC
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| Incidence and significance: patient may have cognitive dysfunction before anesthesia and surgery; genetic predisposition,
abnormalities in lipid metabolism, and vascular pathology or infarction all contributory factors in normal progression
to cognitive impairment in aging; additional surgical stress and anesthesia may affect quality of life (QOL) and
ability to function independently
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| Neurocognitive assessment: occurs before surgery and at varying periods after surgery to determine impact on outcome;
important components—clinically significant (important to patient; relationship to QOL); methodology for
weighting and combining scores (each test measures different domain); addresses regression to mean; practice and learning
effects (improvement generally seen with repetition; decline indicates “something very different has happened”);
floor effect (older patient may be <1 standard deviation [SD] from floor); take into account all factors “and find something
that’s meaningful and interpretable”; ideal to have clinical measure to define cognitive decline; magnetic resonance
imaging (MRI) and computed tomography (CT) can identify new abnormalities occurring in perioperative period, but
cognitive decline may not be directly related (new abnormalities seen on MRI may not lead to new deficit in functional
capacity)
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| Types of neuropsychologic tests: validated and standardized over population; use method that best distinguishes patients
in relation to validation measure; factor decline—factor analysis of 10 measures further reduces them into 4 obvious
independent areas of cognitive function (eg, visuospatial orientation, verbal memory, figural memory); patient
impaired if decline ≥1 SD on any 1 of 4 areas, regardless of what happens in other 3; cognitive index decline—places 4
areas of cognitive function into one continuum to determine if decline equals 1 SD overall; improvement in one area offsets
decline in another area; reliable change index (RCI) vs probability—determine probability of patient being outside
control group; 20-20 measure—20% decline in performance in 20% of tests; strongly criticized because of lack of validation
(but does consider other factors in regression); most tests have mathematically or statistically derived cutoff point
(vs clinically derived cutoff); some factors allow combining raw tests, others do not have appropriate methodology
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| Impact of perioperative cognitive decline on short- and long-term outcome and QOL: study of neurocognitive
function after coronary artery bypass graft (CABG) surgery (Newman et al, 2001)—found incidence of cognitive decline
≈50% at discharge, declining to 36% at 6 wk, 24% at 6 mo, and 42% at 5 yr; cognitive decline at discharge
significant predictor of long-term function (ie, in group with decline at discharge, cognitive function at 5 yr similar to
function at discharge); other significant predictors of cognitive decline—older age; lower level of education; continued
use of higher education delays or prevents perioperative cognitive decline; QOL assessment—at high level of cognitive
function, patients more likely to describe general health as excellent or very good; those at lower level more likely to describe
general health as good or poor; at 5 yr postoperatively, those who continue to function at high level more likely to
be working on full- or part-time basis
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| Strategies for reducing cognitive decline: high-risk patients (eg, cardiovascular disease, diabetes) tend to have
faster cognitive decline; necessary to determine if slope of aging-related cognitive decline in high-risk population
changes with anesthesia and/or cardiac surgery; considering patient and procedural factors, “we’re probably...talking
about something that’s multifactorial”; McKhann et al 2005—looked at of cognitive decline after CABG; compared to
heart-healthy controls, group with coronary artery disease (CAD) had lower cognitive test scores at baseline; no evidence
that cognitive performance of CABG patient differed from that of control groups with CAD over 1 yr; Stent or Surgery
(SoS) trial—found no strong trend in cognitive outcome in patients treated with different revascularization strategies;
concluded disease and/or intervention may determine significance of perioperative cognitive dysfunction; other studies—
speaker’s study comparing patients undergoing CABG vs percutaneous transluminal coronary angioplasty (PTCA) found
that at 6 wk, incidence of decline in cognitive function increased in CABG, but at 1 yr, trend shifted toward greater cognitive
decline with PTCA; study comparing incidence of cognitive decline in noncardiac surgery vs cardiac surgery found
rates “essentially the same,” especially when considering age, race, and other factors (eg, diabetes); therefore, surgical
stress and patient factors as important as procedural factors in determining postoperative cognitive dysfunction; Monk
study of early vs late cognitive decline in elective noncardiac surgery showed older population had substantially greater
incidence than control group; also showed potential correlation between development of cognitive dysfunction and mortality
at 1 yr (unclear whether cause or association)
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| Anesthesia: difficult to sort out anesthetic-based cause of cognitive decline after cardiac surgery
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| Hyperthermia: study found slower rewarming rate in nondiabetic population resulted in improvement in cognition (in diabetic
population, prevented same degree of decline and showed some improvement); same occurs in postoperative period
(correlation between increased temperature [>37°C] and amount of cognitive decline)
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| Hematocrit: study of hemodilution in elderly found decrease in hematocrit from baseline (especially from high to extremely
low) had impact on cognitive decline at 6 wk postoperatively (even if returned to baseline)
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| Etiology (genetic factors): study of genetics and perioperative outcome have found genetic factors to be important to
cognitive outcomes; one study found genetic factors (2 minor alleles related to inflammation and platelet activation) resulted
in absolute risk reduction (50% lower risk for cognitive dysfunction); another study found minor alleles of C-reactive
protein (CRP) gene associated with reduction in cognitive decline; goal— prospective individualized and
personalized care to reduce risk
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| Aortic management: important for stroke overall, but may not be sufficient to reduce cognitive dysfunction
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| WHAT’S NEW IN GERIATRIC ANESTHESIA —Terri G. Monk, MD, MSc, Professor, Department of Anesthesiology,
Duke University School of Medicine, Durham Veterans Affairs Medical Center, Durham, NC
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| Aging population and impact on anesthesiology: dramatic increase in elderly population expected during coming
10 to 15 yr in United States and western world; in 2007, slightly >35 million elderly adults age ≥65 yr; by 2035, number
will double (to ≈70 million elderly adults); old elderly (≥85 yr of age) will increase 4-fold; ≥50% of individuals ≥65 yr of
age will have ≥1 surgery during remainder of life; elderly 3 times more likely to undergo surgery than younger adult
counterparts; number of complications after surgery not determined by age alone, but by combination of age and comorbidities
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| Cognitive changes: 15% of 80-yr-old patients have Alzheimer’s disease; rapidly increases; by 85 yr of age, one-quarter
to one-third have Alzheimer’s disease; many others have mild cognitive impairment (precursor to Alzheimer’s disease)
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| Informed consent in cognitively impaired patients: patient must understand medical condition, intervention,
benefits, side effects, alternatives, and cost; to determine good informed consent, have patient repeat and explain planned
surgery, alternatives, risks, and level of comfort with having surgery; mini-mental state examination (MMSE) recommended
for all patients ≥75 yr of age; cognitively intact patient completes MMSE in ≈5 min; score ≥26 (of 30) considered
normal by neuropsychologists; score of 24 to 26 may indicate mild cognitive impairment (even though patient
functioning independently and living at home); over 7- to 8-yr period, patient with Alzheimer’s disease drops from score
of 26 to score that requires nursing home placement
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| American College of Surgeons recommendations: consult with family members (spouse or children) to ask about any impairment;
if family member unavailable or if questions remain, obtain assessment from geriatric specialist (ideally, psychogeriatrician
[not available in most smaller institutions]; may be family physician); for questions about legal
incompetence in United States, recommendations include obtaining 2 psychiatric opinions to determine if patient competent
to consent to surgery and anesthesia; if patient incompetent and no guardian previously named, patient under protection
of state; courts in United States delegate role of legal representation to private sector; competent family member
normally appointed as guardian (but must still report to court about care of patient); if unable to communicate well with
patient, discharge may be more difficult
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Impact of Aging on Anesthetic Management
| Diastolic dysfunction: by ≥75 yr of age, >50% of individuals have mild, 12% moderate, and 3% to 4% severe diastolic
dysfunction; pathogenesis—elastic properties of tissues decline with age; fibrosis and hypertrophy of left ventricle cause
stiffness at rest and decreased relaxation, resulting in overall increase in diastolic pressure; pathophysiology—decreased
filling of left ventricle; increased chamber stiffness; diagnosed by β-type natriuretic peptide (BNP); normal with mild diastolic
dysfunction without failure, elevated with failure; speaker assumes mild diastolic dysfunction if patient ≥75 yr of age;
more dependent on late diastolic filling to provide volume into left ventricle; patients vulnerable to “flash” pulmonary
edema in operating room (OR) if fluid administered too rapidly or in excessive volumes; management—before surgical
procedure, treat exacerbating factors (eg, hypertension, CAD); maintain slow sinus rhythm (60-70 bpm); be judicious in administering
fluid, yet aware that elderly heart more sensitive to hypovolemia
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| Body temperature regulation: impaired in elderly because of decline in metabolism and reduced vasoconstriction;
especially prone to hypothermia in OR; Ozaki demonstrated vasoconstriction threshold reduced by ≈1°C in elderly during
general anesthesia (compared to younger patients); speaker’s institution uses forced-air heat pumps to blow warm air
under sheets before patient comes to OR; place forced-air heating blanket on patient before induction of anesthesia; maintaining
temperature one of biggest problems in elderly patients
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Postoperative Cognitive Changes
| Types of disorders: postoperative delirium—occurs in 10% to 15% of elderly patients after noncardiac surgery under
general anesthesia (higher after cardiac surgery); dementia—extremely rare; patient never recovers after anesthesia and
surgery (confused; multiple cognitive deficits); patient requires assisted-living or nursing home care; mild neurocognitive
disorder—postoperative cognitive dysfunction; may occur in 10% of cases after noncardiac surgery, and in ≤50%
of cases after cardiac surgery; unknown if disorders separate entities or part of continuum
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| Delirium: defined as disturbance of consciousness; reduced clarity to environment; usually associated with attention
problems (lack focus; cannot carry on conversation; inattentive to time course); usually develops in elderly on second
or third postoperative day; tends to fluctuate during course of day (sundowning, ie, person becomes more confused as
day progresses); potential causes—include drug-induced side effects (especially opiates and benzodiazepines; speaker
reduces use in patient ≥65 yr of age, unless active and healthy; awaken more clearly and quickly), metabolic disorders,
hyperglycemia, renal failure, vitamin deficiency, hypoxemia or hypercapnia, fracture or other trauma, sleep deprivation,
obstructive sleep apnea, and sensory deprivation; eliminate unnecessary drugs; those associated with postoperative
delirium include antiarrhythmic agents, antidepressants, opioids, fentanyl, ketamine, morphine, scopolamine, and
sodium pentothal; study—found increased incidence of death and nursing-home placement associated with postopertive
delirium; study—in patients in intensive care unit (ICU), delirium associated with doubling of length-of-stay; cost
$22,000 more for each patient who developed delirium in ICU; recent abstract—presented at American Society of Anesthesiologists
(ASA) meeting; indicates 50% decrease in postoperative delirium demonstrated when patient lightly
anesthetized with only propofol infusion
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| Postoperative cognitive dysfunction (POCD): mild neurocognitive disorder; deterioration of intellectual function that presents
as impaired memory or concentration; cannot be detected until days or weeks after operative event (follow up with
patient ≥2 wk later to determine if problems continue)
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| Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition (DSM-IV) criteria: indicate diagnosis of mild neurocognitive
disorder made only if corroboration possible with neuropsychologic testing; must test patients before and after
surgery and be able to show evidence of greater memory loss than could be expected due to normal aging and passing
of time; requires control group of age-matched individuals not having surgery who are tested at same time intervals; research
diagnosis (not practical in clinical setting)
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| Study data: any abrupt decline in cognitive function may herald loss of independence, depression, withdrawal from society,
and early death; (important to be empathetic); nature of problem—inability to organize thoughts and plan (case
of lawyer who not only could not remember, but also could not organize thoughts after CABG surgery); frontal lobe
problem with executive function); study from Netherlands—found no difference in cognitive abilities or cardiac outcome
at 5 yr after cardiac surgery between on-pump aand off-pump techniques; Monk et al (2008)—looking at mild
POCD in young, middle-aged, or elderly patients undergoing surgery; 3% to 4% of age-matched controls did worse
on cognitive tests at 1 wk and 3 mo after initial test; however, 30% to 40% of patients (regardless of age) undergoing
major noncardiac surgery had “significant cognitive impairment”; confounding variables (including pain medications
and sleep deprivation) at hospital discharge make it difficult to measure cognition; at 3 mo after surgery, cognitive
function in young and middle-aged groups not significantly different from age-matched controls; however, 13% of
elderly patients (≥60 yr of age) experienced significant cognitive decline (2 SD below function before surgery); independent
predictors—years of education, age, and previous cerebral insult (mild transient ischemic attack [TIA] or
stroke); patients functioning poorly at hospital discharge and at 3 mo postoperatively with persistent cognitive problems
had greater risk of dying in first year after surgery
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Suggested Reading
Albert MS: Changing the trajectory of cognitive decline? N Engl J Med 357:502, 2007; Ely EW et al: The impact of delirium
in the intensive care unit on hospital length of stay. Intensive Care Med 27:1892, 2001; Inouye SK et al: Does delirium
contribute to poor hospital outcomes? A three-site epidemiologic study. J Gen Intern Med 13:234, 1998;
Klopfenstein CE et al: The influence of an aging surgical population on the anesthesia workload: a ten-year survey.
Anesth Analg 86:1165, 1998; Mathew JP et al: Neurologic Outcome Research Group (NORG) of the Duke Heart Center.
Effects of extreme hemodilution during cardiac surgery on cognitive function in the elderly. Anesthesiology 107:577, 2007;
McKhann GM et al: Is there cognitive decline 1 year after CABG? Comparison with surgical and nonsurgical controls.
Neurology 65:991, 2005; Moller JT et al: Long-term postoperative cognitive dysfunction in the elderly ISPOCD1 study.
ISPOCD investigators. International Study of Post-Operative Cognitive Dysfunction. Lancet 351:857, 1998; Monk TG et
al: Predictors of cognitive dysfunction after major noncardiac surgery. Anesthesiology 108:18, 2008; Newman MF et al:
Neurologic Outcome Research Group and the Cardiothoracic Anesthesia Research Endeavors (CARE) Investigators of the
Duke Heart Center. Report of the substudy assessing the impact of neurocognitive function on quality of life 5 years after cardiac
surgery. Stroke 32:2874, 2001; Newman MF et al: Longitudinal assessment of neurocognitive function after coronary-artery
bypass surgery. N Engl J Med 344:395, 2001; Newman MF: Open heart surgery and cognitive decline. Cleve
Clin J Med 74:S52, 2007; Ozaki M et al: The threshold for thermoregulatory vasoconstriction during nitrous oxide/sevoflurane
anesthesia is reduced in the elderly. Anesth Analg 84:1029, 1997; Phillips-Bute B et al: Association of neurocognitive
function and quality of life 1 year after coronary artery bypass graft (CABG) surgery. Psychosom Med 68:369, 2006;
Price CC et al: Type and severity of cognitive decline in older adults after noncardiac surgery. Anesthesiology 108:8,
2008; Puskas F et al: Intraoperative hyperglycemia and cognitive decline after CABG. Ann Thorac Surg 84:1467, 2007;
Währborg P et al: SoS Neuropsychology Substudy Investigators. Neuropsychological outcome after percutaneous coronary
intervention or coronary artery bypass grafting: results from the Stent or Surgery (SoS) Trial. Circulation 110:3411,
2004.
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