Preoperative Assessment in the Older Adult

Lisa Caruso, MD, MPH

Section of Geriatrics

Boston University Medical Center

Goals

• To review the most common physiologic changes in the elderly which may impair one’s ability to compensate for operative stress

• To describe the purpose of the preoperative assessment

• To provide strategies to minimize operative risks

Cardiovascular System

• Changes in “mechanics”– Decrease in myocytes, increase in

collagen resulting in decreased compliance– Autonomic tissue replaced by collagen

resulting in conduction abnormalities– Decreased compliance of vascular system

leading to increased systolic blood pressure with resulting ventricular hypertrophy

Cardiovascular System

• Changes in “control mechanisms”– decreased responsiveness to

catacholamines due probably to impaired receptor function

– decreased heart rate response to changes in circulatory volume may lead to congestive heart failure or hypotension (CO=SV x HR ==>preload dependency)

Pulmonary System

• Reduced chest wall compliance resulting in– increased work of breathing– reduced maximal minute ventilation

• Reduced respiratory response to hypoxia by 50% (? Due to impaired chemoreceptor function)

• Decreased ciliary function

• Reduced cough and swallowing function

Neurologic Changes• Decrease in cortical gray matter, neuronal

volume, complexity of neuronal connections, synthesis of neurotransmitters

• Neuronal loss and demyelination occur in the spinal cord resulting in changes in reflexes and reductions in proprioception

• Vision and hearing loss make information processing more difficult

Renal Changes• Decline in renal blood flow--10% per decade

after age 50• Old kidney has difficulty

– maintaining circulating blood volume– with sodium homeostasis– removing excess acid– adjusting to hypovolemia, hemorrhage, low

cardiac output and hypotension

• Renal insufficiency may not be appreciated

Adverse Drug Reactions (ADR)

• Decrease in lean body mass with increased proportion of body fat

• Decreased protein binding of certain drugs

• Alterations in renal, CV, hepatic function may change drug concentrations and their duration of action

• ADR’s increase with number of drugs administered and linearly with age

Preoperative Assessment--Purposes

• Not just for “clearance”

• To identify factors associated with increased risks of specific complications related to a procedure

• To recommend a management plan to minimize these risks

Cassel CK, Leipzig RM, Cohen HJ, et al. Geriatric Medicine: An Evidence Based Approach, 4th ed. New York: Springer; 2003.

Preoperative Assessment--Components

• Functional Assessment

• Cognitive Assessment

• Nutritional Assessment

• Review of advance directives– whether and when to withhold or withdraw

support

Functional Assessment• American Society of Anesthesiologists

(ASA) score– Class I A normal healthy patient for elective operation– Class II A patient with mild systemic disease

– Class III A patient with severe systemic disease that limits activity but is not incapacitating

– Class IV A patient with incapacitating systemic disease that is a constant threat to life

– Class V A moribund patient that is not expected to

survive 24 hrs with or without the operation

Functional Assessment

• Exercise capacity– “inactive” defined as inability to leave the

home on one’s own at least twice per week– increased CV risk in patients unable to meet

a 4-MET demand during most daily activities

• Activities of Daily Living– Correlated with post-op morbidity and

mortality

Cognitive Assessment

• Not done uniformly

• Dementia is a major predictor of post-op delirium

• Use of Mini-Mental State Exam or orientation and recall testing

• Much potential for future research

Nutritional Assessment• Poor nutrition is a risk factor for

– pneumonia– poor wound-healing– 30-day mortality

• Hypoalbuminemia (<3.3mg/dL)– increased length of stay– increased rates of readmission– unfavorable disposition – increased all-cause mortality

Corti M. Serum albumin level and physical disability as predictors of mortality in older persons.JAMA 1994;272:1036.

Strategies to Minimize Risk• Routine screening is low yield

– preop testing should be based on the type of surgery

• Manage hypertension– lower blood pressure to under 180/110

• In patients with dementia, consider placement of epidural to control pain without sedation thus minimizing risk for delirium

• Avoid long periods without nutrition– little evidence, but should try to improve nutritional

status prior to elective surgery

Strategies to Minimize Risk

• Perioperative use of ß-blockers– Mangano, et al., NEJM 1996, RDBPCT– In patients with or at risk for CAD, does IV atenolol

decrease periop CV morbidity and increase overall survival?

– Cardiac RF included: age > 65, hypertension, smoking, cholesterol > 240, and diabetes.

– 200 pts enrolled; IV atenolol 10 mg given 30 min prior to surgery, 50-100 mg bid POD 1-7

– 192 followed for 2 yrs

Strategies to Minimize RiskTwo years Placebo Atenolol RRR ARR NNT Overall mortality

21% 10% 52% 11% 9

Event-free survival after hospital discharge at 2 years was 68% in the placebo group and 83% in the atenolol group (p=0.008).

Not clear yet if age alone is an indication for use of ß-blockers in perioperative period.

Strategies to Minimize Risk

• Diabetic Postoperative Mortality and Morbidity (DIPOM) study

• Perioperative Ischemic Evaluation (POISE) trial

• Metoprolol after Vascular Surgery (MaVS) trial

Http://www.medscape.com/viewarticle/494679

Reuben DB, et al. Geriatrics at Your Fingertips 2005, 7th edition. New York, American Geriatrics Society, 2005.

Summary

• Older adults have decreased reserves in multiple organ systems.

• Disease burden and functional capacity outweigh age when assessing preoperative risk.

• Collaboration among providers helps to identify functional, cognitive and nutritional deficits and to create management plans to minimize these deficits when possible.