Preoperative and preooperative issuesin the orthopaedic surgical patient

PREOPERATIVE AND PERIOPERATIVE ISSUES IN THE ORTHOPAEDIC SURGICAL PATIENT FRED H. RUBIN, MD

Elderly patients account for most cases of hip fracture, total hip replacement, and total knee replacement surgery. Although surgery in the elderly is associated with greater risk than in younger patients, this risk is due primarily to cornorbidities and not to the normal aging process. Careful preoperative evaluation is required and should focus on optimizing the status of patients' chronic medical problems and on assessing their degree of risk of a perioperative cardiac event. The algorithm published by the American College of Cardiology and the American Heart Association is presently the best tool available for such assessment. Postoperatively, the elderly are at increased risk for multiple complications, of which delirium and adverse drug reactions are the most common. The elderly are also more likely to reqttire posthospital rehabilitation in an institutional setting. With advance planning and careful monitoring, the great majority of elderly patients can safely undergo any surgical procedure. KEY WORDS: preoperative assessment, geriatric, iatrogenesis Copyright 2002, Elsevier Science (USA). All rights reserved.

The elderly comprise an increasing proportion of orthopedic surgical patients. They are at increased risk for fractures due to the increased prevalence both of osteoporosis and of gait instability in later life. As shown in Figure 1, hip fracture is predominantly a syndrome of the elderly. 1 Additionally, they have lived long enough to have reached end-stage degenerative joint disease, particularly of knees and hips. America's population is aging rapidly, creating a 'demographic imperative' to adapt to large numbers of seniors. As exhibited in Figure 2, there will be over 50 million people in this country over age 65 by 2020, comprising nearly 20% of our population. 2

PREOPERATIVE EVALUATION There are five factors that influence morbidity and mortality after surgery: the type of procedure, whether elective or emergency, chronological age of the patient, presence of coexistent pathologies, and general health of the patient. Of these, the least important is the patient's age. Age by itself is not an absolute contraindication to any procedure. The normal physiological changes of aging do cause a modestly increased surgical risk, but the major predictor of risk is the presence of concomitant diseases. Someone with unstable angina is a poor risk at any age, whereas a perfectly healthy 90- year-old patient can be considered for almost any procedure. As a rule-of-thumb, the perioperative mortality for patients below age 65 is about 1% and rises to 5% above 65. The assessment of a specific patient for a specific procedure must always be individualized.

From the University of Pittsburgh, School of Medicine, UPMC Shadyside. Pittsburgh, PA. Address reprint requests to Fred H. Rubir, MD. UPMC Shadyside, 5230 Centre Avenue, Pittsburgh, PA 15232. E-mail: [email protected] Copyright 2002, Elsevier Science (USA). All rights reserved. 1048-6666/02/1202-0000535.00/0 doi:10.1053/otor.2002.36165

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The elderly are the most heterogeneous section of the population; two 80 year olds with the same birthday can look drastically different and pose very different degrees of risk. Age by itself does convey a somewhat increased risk of surgery. Numerous physiologic functions worsen with age, such as glomerular filtration rate, vital capacity, and cardiac index. However, although most parameters are maximal around age 30 and decrease thereafter, none of them decline below a threshold that would produce symptoms. A healthy person of advanced age should still be able to function normally in daily life, but when stressed will have less reserve capacity. The risk of surgery attributable entirely to age was recently clarified in a prospective study of 4,300 patients over age 50 shown in Figure 3.3 The normal physiology of aging represents simply the baseline of organ function. Superimposed are the deleterious effects of lifestyle choices, such as cigarette smoking or lack of regular exercise, and the effects of concurrent disease, especially atherosclerosis. What evaluation is required preoperatively? First is a set of basic tests that the anesthesiologist will require of all elderly patients. These include a recent EKG, chest x-ray within the past year, a complete blood count (CBC), a basic metabolic profile (BMP), and a urinalysis if a prosthesis is to be implanted. Second are studies pertinent to individual patients based on their comorbidities, such as pulse oximetry, arterial blood gases, a n d / o r pulmonary function studies in a patient with chronic obstructive pulmonary disease (COPD). The major concern is evaluation of the patient's cardiac status. In 1977 Goldman and coworkers showed that the risk of a perioperative cardiac event was predictable by the number of risk factors present preoperatively.4 They created the Multifactorial Cardiac Risk Index, which is easy to calculate and has become widely utilized. However, although the specificity was good, the sensitivity was only about 50%. A number of other indices have subsequently been published. 5-9 Recently, the AmerOperative Techniquesin Orthopaedics,Vol 12, No 2, 2002: pp 60-63

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Incidence/ Fig 1. Incidence of fracture of the distal forearm and of the proximal femur by age-group. (Reprinted with permission. 2)

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ican College of Cardiology and the American Heart Association issued joint guidelines for cardiac risk stratification and management 1° involving a complex algorithm, illustrated in Figure 4. They divided clinical risk factors into major, intermediate, and minor predictors. Major risks include unstable coronary syndromes, decompensated congestive heart failure (CHF), significant arrhythmias, and severe valvular disease. Intermediate risks include mild angina pectoris, prior myocardial infarction, compensated CHF, diabetes mellitus, and renal insufficiencv. Minor risks include advanced age, abnormal EKG, rhythm other than sinus, low functional capacity, history of stroke, and uncontrolled hypertension. The guidelines stratify functional capacity into excellent, moderate, and poor levels, based on aerobic demands for specific activities, expressed in metabolic equivalents (METs). They also stratify surgery-specific risk into high-, intermediate-, and lowrisk categories based on the type of surgery, whether an emergency, and the degree of hemodynamic stress associated with the procedure. For instance, aortic or other major vascular surgery would be high risk. Details of the algorithm can be found in reference 10 or online at www.acc.org. Applying the algorithm leads to a decision to proceed with surgery, to cancel surgery pending coro-

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nary artery intervention, or to delay surgery for additional noninvasive cardiac testing to further clarify the patient's risk of a cardiac event perioperatively. The majority of patients would be expected to be able to proceed with surgery without delay. It is becoming increasingly common for patients with known coronary artery disease or with two or more risk factors to receive perioperative beta-blockers, which have been shown in two randomized controlled trials to reduce the incidence of cardiac events. 11,12 The third area for preoperative assessment of an elderly patient is anticipation of rehabilitation and posthospitalization needs. Does this person live alone? Is there any family nearby? Will they need assistance with activities of daily living (ADLs)? Can rehabilitation be accomplished at home, or will they need to spend time in an acute rehabilitation hospital or a skilled nursing facility? The evershrinking length of a modern hospital stay requires advance planning for discharge. The fourth issue is optimization of the patient's medical condition. Problems such as anemia, infection, dehydration, or uncontrolled hypertension should all be addressed preoperatively. It has recently been shown that delaying hip fracture repair to correct medical problems does not adversely affect the surgical outcome. 13 Intraoperative concerns in elderly patients are generally very well managed b y the anesthesiologist and will not be discussed here, except to note that the choice of spinal versus general anesthesia appears to have no effect on either morbidity or mortality.

70

65 6O 55 5O

POSTOPERATIVE MANAGEMENT

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4O 35 30 25 1990

2000 2010

2020

2030

2040

2050

Fig 2. Projected growth in 65+ population 1990 to 2050. (Graph based on U.S. Census Bureau data, 2) PREOPERATIVEAND PERIOPERATIVEISSUES

Elderly patients are substantially more likely to suffer postoperative complications. The most common of these are shown in Table 1. Delirium may occur in half of all elderly orthopedic patients. It is usually multifactorial in etiology, especially since the elderly carry a high burden of comorbidities. Some of the patient's baseline conditions that make her more vulnerable to an episode of delirium include advanced age, cognitive impairment, a history of alcohol or drug abuse, impaired vision or hearing, poor functional status, and azotemia. Some of the insults to which patients are exposed in the hospital can also contribute to delirium, such as sleep deprivation, use of re-

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[]

In-hospital mortality

[]

Cardiac complications

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Noncardiac complications

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Fig 3. Major postoperative complications and inhospital mortality in patients undergoing noncardiac surgery. (Reprinted with perrmission. 3)

[] Overall major complications

Age, y

straints, and new medications. Notable among the latter is the use of meperidine (Demerol), a commonly used narcotic which is metabolized to normeperidine, that may produce an agitated delirium with repeated doses. In general, morphine is preferred over meperidine for use in the elderly. Delirium is very serious: it is associated with a doubling of the mortality rate, longer length of stay, worse functional status at discharge, and increased risk of transfer to a nursing home. Half of the patients who become delirious are not back to normal even 6 months later. 14 There is evidence that targeted interventions for patients at risk for delirium can prevent its development. 15,16 Delirium is discussed more fully elsewhere in this issue. Another major concern [s the occurrence of deep vein thrombophlebitis (DVT) and the risk of subsequent pulmonary embolus (PE). Based on published studies of elderly orthopedic patients undergoing venography postoperatively, the prevalence of any DVT is 45 to 57% for total hip replacement, 40 to 84% for total knee replacement, and 36 to 60% for hip fracture surgery. 17 The prevalence of any PE has been reported to be 0.7 to 30% for total hip replacement, 1.8 to 7% for total knee replacement, and 4.3 to 24% for hip fracture surgery. 17 Although most of these complications will be asymptomatic, prophylaxis against DVT/PE is strongly recommended. Although multiple regimens are available, the most recent consensus conference of the American College of Chest Physicians, based entirely on published evidence, supports the use of either adjusted-dose warfarin (Coumadin) or low-molecularweight heparin (LMWH).17 There is no clear evidence in favor of starting anticoagulation either 12 hours before or 12 to 24 hours after surgery. If warfarin is used, the target for the international normalized ratio (INR) is 2.0 to 3.0. If

Patient's I Cardiac Risk

I

Patients

I

I

Procedure's

Degree of Risk

a LMWH is chosen, there appear to be no significant differences in efficacy between the four types currently available in this country (enoxaparin, dalteparin, tinzapatin, and nadroparin). Danaparoid, argatroban, bJrudin, and most recently fondaparinux are also available but have been less well-studied than the LMWH's. Although there is evidence that fondaparinux in particular may be more effective than a LMWH, these nonheparin agents should probably be reserved for patients at risk for heparin-induced thrombocytopenia until more data are published. The ideal duration of prophylaxis is unknown but should probably be longer than 10 days. Routine duplex ultrasonography screening at hospital discharge has not been shown to be useful. The presence of an epidural catheter is generally considered a contraindication to systemic anticoagulation. Because LMWH's and fondaparinux are renally excreted, these drugs should be used cautiously or not at all in the presence of renal failure. As noted above, patients with coronary artery disease or with two or more risk factors should receive beta blockers perioperatively if there are no contraindications, but the duration of this therapy is unclear. At a minimum, one would continue ur~til hospital discharge. Additionally, patients with CAD should be screened for perioperative cardiac events with at least one EKG in the postoperative period. The most common fluid and electrolyte disorders in hospitalized seniors are dehydration and hyponatremia. At least one postoperative BMP should be checked and appropriate therapy instituted if necessary. Nosocomial infection is common in hospitalized seniors, especially involving the urinary tract, lower respiratory tract, and skin. Such infections will often present with mental status changes and should be sought in every patient who becomes delirious. Infected prostheses present specific problems that are discussed elsewhere in this issue.

TABLE 1. Common Postoperative Problems Delirium Thromboembolic disease Myocardial ischemia or infarction Inadequate nutrition Fluid and electrolyte disturbances

Infection

1 Proceedto Surgery

J

[ Non-invasive Testing

l CardiacCath 1 & Intervention

Fig 4. Model for the ACC/AHA algorithm

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Mesenteric ischemia Immobility and deconditioning latrogenesis

Atelectasis

FRED H. RUBIN

I m m o b i l i t y is a particular h a z a r d for the elderly. It increases the risk of d e v e l o p i n g decubitus ulcers, u r i n a r y incontinence, fecal impaction, thrombophlebitis, physical deconditioning, depression, osteoporosis, a n d delirium. Early a m b u l a t i o n is vital postoperatively. Iatrogenesis is the i n a d v e r t e n t creation of illness as a consequence of a diagnostic p r o c e d u r e or a therapeutic intervention. The b u r d e n of iatrogenesis a m o n g hospitalized patients falls p r e d o m i n a n t l y on the elderly, w h o are especially vulnerable d u e to frailty a n d multiple c o m o r bidities. All physicians a n d other health care w o r k e r s h a v e an obligation to k e e p our patients safe a n d to reduce iatrogenesis as m u c h as possible. The hospital environm e n t is h a z a r d o u s , a n d errors are not rare. W e m u s t w e i g h the risks and benefits of each p r o c e d u r e a n d of each n e w medication. N o r m a l a g i n g leads to the following p h a r m a cokinetic changes m d r u g metabolism: gastrointestinal absorption is reduced; cellular receptors for s o m e d r u g s are reduced; oxidation a n d r e d u c t i o n reactions in the liver are decreased; g l o m e r u l a r filtration rate is decreased; a n d b o d y c o m p o s i t i o n is altered such that the w a t e r c o m p a r t m e n t is reduced, while the lipid c o m p a r t m e n t is increased. A d r u g such as digoxin (Lanoxin), w h i c h is b o t h lipophilic a n d renally excreted, m u s t be a d m i n i s t e r e d in r e d u c e d doses to p r e v e n t toxicity. Medications are the leading cause of iatrogenesis. A d v e r s e d r u g reactions (ADRs) m a y result f r o m d r u g - d r u g interactions, d r u g - d i s e a s e interactions, o v e r d o s a g e , side effects, or allergy. ADRs occur in u p to 20% of all hospitalized patients. 18 P o l y p h a r m a c y , the c o n c o m i t a n t a d m i n i s t r a t i o n of multiple medications, should be m i n i m i z e d . R e g a r d i n g n e w medications, the a p h o r i s m 'Start low a n d go s l o w ' is wise advice. M o r e rarely, s u r g e r y can b e c o m p l i c a t e d b y p o s t o p e r a tive renal, hepatic, or r e s p i r a t o r y failure. These will generally necessitate medical consultation. Finally, one m u s t anticipate posthospitalization rehabilitation needs. A m o n g elderly patients w i t h hip fracture, 25% are n e v e r able to return to i n d e p e n d e n t living, a n d 50% do n o t regain their p r i o r level of function. T w e n t T five p e r c e n t die within 1 y e a r of the event, b u t this p r o b ably reflects the frail n a t u r e of elderly p e o p l e w h o suffer injurious falls.

CONCLUSIONS Surgery in the elderly is associated with greater risk t h a n in y o u n g e r patients, b u t this risk is d u e p r i m a r i l y to comorbidities a n d not to the n o r m a l aging process. Because the elderly are such a h e t e r o g e n e o u s group, decision m a k ing m u s t be highly individualized. Risks can be assessed p r e o p e r a t i v e l y and m i n i m i z e d , especially the risk of a

PREOPERATIVE AND PERIOPERATIVE ISSUES

cardiac event. Delaying s u r g e r y to o p t i m i z e the patient's medical status is occasionally p r u d e n t . Postoperatively o u r goal is not only to help the patient recover f r o m s u r g e r y b u t also to anticipate complications, protect the patient f r o m the h a z a r d s of hospitalization, m i n i m i z e loss of function, a n d m i n i m i z e the incidence of c o m m o n p r o b lems such as delirium a n d thrombophlebitis.

REFERENCES 1. Riggs BL, Melton LJ: Evidence for two distinct syndromes of involutional osteoporosis. Am J Med 75:899-901, 1983 2. United States Census Bureau: www.census.gov/prod/1/pop/9 3. Polanczyk C, Marcantonio E, Goldman L, et al: Impact of age on perioperative complications and length of stay in patients undergoing noncardiac surgery. Ann Intern Med 134:637~643, 2001 4. Goldman L, Caldera DL, Nussbaum SR, et ah Multifactorial index of cardiac risk in noncardiac surgical procedures. N Engl J Med 297: 845-850, 1977 5. Detsky AS, Abrams HB, McLaughlin JR, et al: Predicting cardiac complications in patients undergoing non-cardiac surgery. J Gen Int Med 1:2tl-219, 1986 6. Gerson MC, Hurst JM, Hertzberg VS, et al: Cardiac prognoses in non-cardiac geriatric surgery. Ann Intern Med 103:832-837, 1985 7. American College of Physicians: Guidelines for assessing and managing the perioperative risk from coronary artery disease associated with major non-cardiac surgery. Ann Intern Med 127:309-312, 1997 8. Lee TH, Marcantonio ER, Mangione CM, et al: Derivation and prospective validation of a simple index for prediction of cardiac risk of major noncardiac surgery; Circulation 100:1043-1049, 1999 9. Boersma E, Poldermans D, Bax JJ, et al: Predictors of cardiac events after major vascular surgery. JAMA 285:1865-1873, 2001 10. Eagle KA, Berger PB, Calkins H, et al: ACC/AHA guidelines update for perioperative cardiovascular evaluation for noncardiac surgery-executive summary. J Am Colt Cardiol 39:542-553, 2002 11. Poldermans D, Boersma E, Bax JJ, et ah The effect of bisoprolol on perioperative mortality and myocardial infarction in high-risk patients undergoing vascular surgery. N Engl J Med 341:1789-1794, 1999

12. Mangano DT, Layug EL, Wallace A, et al: Effect of atenolol on mortality~ and cardiovascular morbidity after non-cardiac surgery. N Englj Med 335:1713-1720, 1996 13. GrimeS JP, Gregory PM, Noveck H, et al: The effects of time-tosurgery on mortali~ and morbidity in patients following hip fracture~ Am J Med 11:702-709, 2002 14, Levkoff SE, Evans DA, Liptzin B, et al: Delirium: The occurrence and persistence of symptoms among elderly hospitalized patients: Arch Intern Med 152~334-340~1992 15. Marcantonio ER, Flaeker JM, Wright RJ, et al: Reducing delirium after hip fracture; a randomized trial, J Am Geriatr Soc 48:516-522, 2001 16. Inouye SK, Bogardus ST, Baker DI, et al: The Hospital Eider Life Program: A model of Careto prevent cognitive and functional decline oide~ h0s?italizea patients. J Am Geriatr Soc 48:1697-1706, 2000 17. Geerts WH; Heit JA~ Clagett GP, et al: Prevention of venous thromboemb6!!sm: Chest !19J325-1755, 2001 18. Kohn LT, Corriga~ JM, Donaldson MS (eds): To Err Is Human. Was~gton, DG Institute of Medicine, National Academy Press, 1999

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