AAOS Comprehensive Orthopaedic Review

Section 2 - General Knowledge

Chapter 17. Perioperative Medical Management

I. Assessment

A. Goals of preoperative medical assessment

 

1. Assess the risk of potential perioperative mortality and morbidity.

 

2. Determine whether a patient's medical condition can be optimized before elective surgery.

 

B. Patient's "readiness" for surgery

 

1. Determined by the patient's anesthesiologist on the day of surgery.

 

2. Includes risk assessment for intraoperative and acute postoperative outcomes.

 

3. Includes evaluation of preexisting conditions, both related and unrelated to the planned surgical procedure.



II. Preoperative Evaluation

A. A thorough history and physical examination is necessary and can be conducted by a primary care physician, internist, hospitalist, or other physician.

 

B. Systems-based approach includes all body systems.

 

C. Goals of the history and physical examination are to identify an undiagnosed, poorly managed, or other condition. Such conditions can place the patient at a higher perioperative risk for morbidity and mortality.



III. Preoperative Testing

A. Blanket testing is not cost effective in planning care of a general population of patients.

 

B. Patients with specific comorbidities should be screened using tests relevant to their disease.

 

C. A directed bleeding history (

Table 1) is more effective for assessing the risk of abnormal surgical bleeding than routine screening with platelet counts, International Normalized Ratio (INR), or bleeding time tests.



IV. Assessment of Cardiac Risk

A. Key preoperative steps include:

 

1. Identifying patients with new or unstable cardiopulmonary symptoms for additional preoperative testing (eg, noninvasive stress tests, catheterization).

 

2. Beginning preventive therapies, if needed, even though preoperative revascularization does not improve outcomes after orthopaedic surgery except in patients who already require angioplasty or bypass surgery.

 

3. Planning for postoperative monitoring in high-risk patients.

 

4. Ordering a preoperative electrocardiogram (ECG) for all patients with a history of coronary artery disease, vascular disease, or cerebrovascular disease.

 

B. Risk factors for coronary artery disease

 

1. Age >50 years

 

[Table 1. Elements of a Directed Bleeding History]

[

Table 2. Revised Cardiac Risk Index (RCRI)]

2. Family history

 

3. Diabetes

 

4. Hypertension

 

5. Smoking

 

C. Use of β-blockers

 

1. β-blockers should be administered perioperatively only in patients at high risk (eg, Revised Cardiac Risk Index [RCRI] of 2 or more; Table 2 and

Figure 1), with documented coronary disease, or who are currently taking β-blockers.

 

2. β-blockers should be administered preoperatively (optimally 1 week or more before surgery), titrated to a therapeutic heart rate (55 to 70 beats/min) throughout hospitalization, and continued for 7 days after surgery (or indefinitely, if patients are already on β-blockers).



V. Assessment of Pulmonary Risk

A. Pulmonary complications such as pneumonia and respiratory failure are probably more common than cardiac complications.

 

B. Diagnostic testing

 

1. Chest radiographs are indicated if patients have signs or symptoms of pulmonary disease (baseline oxygen requirement, crackles, rhonchi, wheezing).

 

2. Arterial blood gas measurements and pulmonary function testing are indicated in the following situations:

 

a. With severe or unexplained symptoms.

 

b. If the etiology of the underlying diagnosis—eg, chronic obstructive pulmonary disease (COPD), congestive heart failure (CHF)—is unclear.

 

[Figure 1. Event rates by Revised Cardiac Risk Index score.]

c. If the information is needed to plan for postoperative airway management (eg, extubation in the operating room, postanesthesia care unit, or requirement for intensive care unit).

 

C. Physical examination, particularly assessment of functional status (ability to climb one flight of stairs), is probably more predictive of pulmonary risk than preoperative tests.

 

D. Ways to reduce the risk for postoperative pulmonary complications

 

1. Treating exacerbations of COPD or asthma adequately preoperatively

 

2. Early mobilization of patients, including early ambulation, sitting up in bed, or sitting in a chair

 

3. Use of incentive spirometry every hour while awake in all patients

 

4. Targeted use of nebulizers

 

5. Use of noninvasive ventilation (eg, bilevel positive airway pressure [BiPAP] or postanesthesia care unit) or intensive care unit in selected patients whose respiratory status is tentative



VI. Special Considerations

A. Renal/hepatic insufficiency

 

1. Risk for complications is higher than in unaffected patients.

 

2. Consult or referral to the appropriate medical specialist is needed.

 

3. Patients on dialysis should undergo hemodialysis

 

[

Table 3. Marcantonio Delirium Risk Index]

   the evening before or morning of surgery, with close attention to electrolytes and fluid status afterward.

 

4. Close attention to bleeding risk, fluid status, and risk of oversedation and impaired hepatic clearance of opioids and benzodiazepines is needed in patients with liver disease.

 

5. Drug dosing in patients with cirrhosis and renal failure must be modified according to the severity of their renal or liver disease.



VII. Diabetes

A. Blood glucose levels in orthopaedic surgical patients should be maintained between 110 and 150 mg/dL throughout the perioperative period to reduce the risk of complications (eg, surgical site infections).

 

B. Preoperative insulin dosing

 

1. Patients with type II diabetes should hold or take a reduced amount of their usual oral medications the morning of surgery.

 

2. Patients with type I diabetes should take a smaller than usual morning dose of insulin while NPO and awaiting surgery.

 

3. Regardless of the type of diabetes, the management plan depends on the time of day the procedure takes place, the patient's medication regimen, and the how well blood glucose levels are controlled at baseline.

 

C. Other types of insulin dosing

 

1. Insulin infusions are optimal therapy for patients in intensive care, on enteral or parenteral feedings, and who have persistent hyperglycemia.

 

[

Figure 2. Event rates by Marcantonio Delirium Risk Index.]

2. Split-dose sliding scales, which combine longer-acting insulin at regular intervals with short-acting (aspart or regular) insulin for correction, are recommended.

 

3. Regular insulin sliding scales (eg, sliding scales that use a single type of short-acting insulin to control blood glucose) should be avoided because they are ineffective at maintaining tight glucose control.

 

D. Oral agents should be resumed as soon as the patient can tolerate taking oral medications.



VIII. Postoperative Delirium

A. Incidence and risk factors

 

1. Postoperative delirium is a very common complication of orthopaedic surgery, particularly in patients with hip fracture.

 

2. Many risk factors for delirium mirror risks for postoperative cardiac complications. Risk indices for postoperative delirium also exist, and they accurately identify patients in whom delirium is likely (Table 3 and Figure 2).

 

3. All patients should be asked if they have experienced postoperative confusion. A positive answer is highly specific, and prompt preventive measures are needed.

 

4. Patients with no history of postoperative delirium

 

a. Preoperative evaluation should include assessments for dementia or other cognitive disorders (eg, sundowning, or late-day confusion). Both the patient and the family should be questioned.

 

b. Risk factors for postoperative delirium in this group include a history of alcohol abuse, stroke, and marked metabolic abnormalities (eg, elevated blood urea nitrogen [BUN], elevated glucose).

 

B. Management

 

1. The overall goal is to reduce the duration and severity of symptoms so that postoperative care (eg, early mobilization, physical therapy, compliance with incentive spirometry) can continue.

 

2. Assess the severity of pain. The delirious patient who reports pain should be treated with the most effective therapy possible (even including opioid analgesics).

 

3. Assess and treat for other complications such as infection, hypoxemia, hyperglycemia, or hypovolemia.

 

4. Minimize iatrogenic factors, particularly the use of urinary catheters and anticholinergic medications.

 

5. Encourage family and friends to accompany the patient as much as possible to help reorient and reassure the patient in the immediate postoperative period.

 

6. Medications

 

a. Haloperidol (0.5 to 1.0 mg intramuscular) can be used hourly until symptoms are controlled. Monitor ECG and QT interval during its use.

 

b. Benzodiazepines such as lorazepam should be used in patients who are agitated and whose symptoms are not controlled by haloperidol.

 

7. Restraints are an option of last resort.



IX. Rheumatologic Considerations

A. Cervical instability should be suspected in any patient with rheumatoid arthritis.

 

B. Screen for cervical instability specifically using CT or plain radiographs of the neck.



X. Medication Management

A. Steroids

 

1. Despite few data to direct whether patients undergoing surgery who have been on long-standing steroid treatment require "stress dose" steroids, this practice is common.

 

2. If stress dose (eg, hydrocortisone 100 mg every 8 hours) steroid supplementation is used, it should be of very short duration (36 hours), after which time the outpatient steroid regimen should resume.

 

B. Aspirin

 

1. The practice of holding aspirin before surgery, while prudent in concept, is fairly unsupported by evidence.

 

2. Although it is reasonable to discontinue aspirin in most patients, continuing aspirin should be considered in patients with any implanted coronary device (eg, coronary stent) because of the high risk of acute coronary occlusion.

 

C. Warfarin

 

1. The plan for managing warfarin perioperatively in orthopaedic patients depends on the indication for long-term anticoagulation.

 

a. Low-risk groups (atrial fibrillation without prior stroke; cardiomyopathy without atrial fibrillation)

 

i. These patients have an annual thrombotic risk (without anticoagulation) of less than 4%.

 

ii. They can be managed by withholding anticoagulant medication for the 4- to 6-day perioperative period.

 

iii. Stop warfarin in these patients 5 days before surgery and check INR 1 day before surgery to confirm that it is below 1.5.

 

iv. Restart warfarin as soon as possible after surgery.

 

b. Moderate-risk patients (mechanical aortic valve, risk of stroke off warfarin between 4% and 7%)

 

i. These patients require "bridging" anticoagulation.

 

ii. Low-molecular-weight heparin (LMWH) is preferred for bridging therapy because it can be initiated while the patient is at home (as opposed to unfractionated heparin, which requires admission).

 

c. High-risk patients (mechanical mitral valve; atrial fibrillation with prior stroke)

 

i. These patients have an annual risk > 7%.

 

ii. They require "bridging" anticoagulation.

 

iii. LMWH is preferred for bridging therapy because it can be initiated while the patient is at home (as opposed to unfractionated heparin, which requires admission).

 

2. Bridging therapy

 

a. Discontinue warfarin 5 days before surgery and 36 hours after the last dose of warfarin.

 

b. Check the INR 1 day before surgery to confirm it has decreased to below 1.5.

 

c. Discontinue 12 to 24 hours before surgery.

 

d. Resume once hemostasis has been achieved; restart warfarin at the patient's usual outpatient dose at the same time.

 

e. Unfractionated heparin or LMWH is discontinued once the INR is greater than 2.0.



Top Testing Facts

1. Choose preoperative tests that assess for stability of current comorbidities or diagnose unclear symptoms or signs. Blanket testing policies are not cost effective and can be misleading.

 

2. A directed bleeding history can help to identify patients for whom preoperative bleeding tests are most useful.

 

3. The RCRI is a simple and highly predictive way to identify patients who should be referred to cardiology or should have surgery delayed.

 

4. Risk for cardiac events can be substantially lowered if β-blockers are used appropriately in high-risk patients, specifically those with two or more RCRI criteria.

 

5. Pulmonary complications such as pneumonia and respiratory failure are probably more common than cardiac complications.

 

6. Risk for pulmonary complications can be managed through treating an exacerbation of asthma or COPD before surgery, as well as early mobilization, use of incentive spirometers, nebulizers, and noninvasive ventilation (such as BiPAP).

 

7. In general, maintaining blood glucose levels below 150 mg/dL in postoperative patients is optimal. Achieving this goal requires use of insulin infusions (ICU patients) or sliding scales, which include both short- and longacting insulin.

 

8. Postoperative delirium is common, and can be managed effectively by minimizing noxious stimuli (eg, pain, indwelling urinary catheters, restraints), and by reorienting patients as often as possible.

 

9. Careful consideration of continuing aspirin in patients with coronary artery stents is required; these patients are at high risk for stent restenosis and death if anti-platelet agents are discontinued.

 

10. Management of warfarin around the time of surgery is predicated on the underlying reason for warfarin use—in general, shorter duration of time off warfarin (or bridging therapy with heparin) is required for patients at higher risk for thrombotic complications when not anticoagulated.



Bibliography

Auerbach A, Goldman L: Assessing and reducing the cardiac risk of noncardiac surgery. Circulation 2006;113:1361-1376.

Baker R: Pre-operative hemostatic assessment and management. Transfus Apher Sci 2002;27:45-53.

Douketis JD: Perioperative anticoagulation management in patients who are receiving oral anticoagulation therapy: A practical guide for clinicians. Thromb Res 2002;108:3-13.

Hoogwerf BJ: Perioperative management of diabetes mellitus: How should we act on the limited evidence? Cleve Clin J Med 2006;73(suppl 1):S95-S99.

Marcantonio ER, Flacker JM, Wright RJ, Resnick NM: Reducing delirium after hip fracture: A randomized trial. J Am Geriatr Soc 2001;49:516-522.

Smetana GW: Preoperative pulmonary evaluation: Identifying and reducing risks for pulmonary complications. Cleve Clin J Med 2006;73(suppl 1):S36-S41.