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Diabetes mellitus

Collagen vascular disease

Certain malignancies

Certain infectious disease

Use of medication with potential cardiac toxicity

Doxorubicin

Phenothiazines

Tricyclic antidepressants

Consider in:

Planned intrathoracic, aortic, intraperitoneal, or emergency procedures

Men >40–45 years of age and women >55 years of age

Chest radiograph

Intrathoracic surgical procedures

Active chest disease on history and physical examination

Elderly patients, selected

DI, diabetes insipidus; SIADH, syndrome of inappropriate secretion of antidiuretic hormone. Adapted from Ziring BS. In: Merli EJ, Weitz HH, eds. Medical Management of the Surgical Patient. Philadelphia: WB Saunders; 1992.

Prior difficulties with surgical procedures or anesthetics

Familial disorders, such as bleeding disorders (e.g., von Willebrand's disease) or anesthetic complications (e.g., malignant hyperthermia)

C Physiologic parameters

Attention to certain physiologic parameters in preoperative patients lowers operative risk.

Volume status (see Chapter 1, I) should be assessed.

Factors to consider include:

Past and current weight

Skin turgor, mucous membrane moistness, and presence of axillary sweat

Jugular venous distention or pulmonary rales

Alterations in vital signs, such as blood pressure and heart rate

In acute situations, volume status abnormalities should be treated promptly (see Chapter 1, I).

Orthostatic blood pressure changes can be determined by a comparison of the supine and the upright blood pressures.

Urine output should be determined hourly if time permits.

Even in urgent cases (e.g., a perforated viscus), it may be beneficial to stabilize volume status preoperatively.

Electrolyte abnormalities (see Chapter 1, I) should be corrected.

The presence of nausea, vomiting, diarrhea, chronic anorexia, or bowel obstruction can be associated with dehydration and electrolyte shifts.

In acute situations, serum electrolyte levels may not reflect the true fluid or metabolic status and should be interpreted with the clinical picture in mind.

Red blood cell (RBC) mass (see Chapter 1, IV C) should be evaluated.

Acute blood loss may not alter the peripheral blood hematocrit for up to 24 hours. Therefore, the need for RBC replacement should be determined from other variables, such as sites of obvious blood loss.

Chronic anemia is usually well compensated by an increase in plasma volume.

The cause of the anemia should be determined, because the underlying disease may affect the planned surgery.

For example, patients with sickle cell anemia frequently develop cholelithiasis. Hydration and oxygenation should be carefully maintained in these patients during cholecystectomy to avoid precipitating a sickle cell crisis.

Measures to conserve or increase RBC mass follow.

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Autologous blood donation can be considered in elective cases with anticipated blood loss in order to reduce the risk of acquiring transmissible disease (see Chapter 1, IV B 3).

Oral or parenteral iron supplements should be given to patients who have an iron deficiency and to those undergoing autologous donation or receiving erythropoietin.

Recombinant human erythropoietin stimulates RBC production. It may be useful in patients with renal failure–related anemia, anemia of chronic disease, in association with autologous donation, or in patients who refuse transfusion.

Intraoperative blood salvage and autotransfusion of recovered blood can be utilized if not specifically contraindicated by the presence of infection, contamination, or malignancy.

Operative blood loss should be minimized with effective surgical hemostasis.

Criteria for allogeneic RBC transfusion are not fixed. Consideration must be given to the patient's medical status (i.e., the presence of underlying pulmonary, cardiac, and cardiovascular disease), theduration of anemia , and the blood loss anticipated during the procedure. This must be weighed against the risk; allogeneic transfusion has been associated with increased rates of pneumonia and perioperative infection and increased mortality.

In general,

Patients with hemoglobin greater than 10 g/dL generally do not require transfusion.

Patients with hemoglobin between 7 and 10 g/dL compensate adequately and require an individual assessment of the risks and benefits prior to transfusion.

patients were:

Admission serum albumin

ASA class

Disseminated cancer

Emergency operation

Age

Blood urea nitrogen (BUN) >40 mg/dL

Do Not Resuscitate orders

Operation complexity score

SGOT >40 IU/mL

Weight loss >10% in 6 months

Functional status

WBC >11,000/mm 3

E Prevention of complications

In certain acute conditions, such as appendicitis and small bowel obstruction, the overall prognosis depends on interventions that halt the natural progression of the disease. It is important to establish the diagnosis and to begin treatment before complications develop, even if a surgical procedure is required for diagnosis. For example, the overall mortality rate for simple appendicitis without rupture is lower than 1%, but the rate increases in patients with a ruptured appendix.

F Patient education

Ensuring that the patient has a realistic understanding of the prognosis and the expected outcome of the operative procedure helps to ensure the patient's cooperation postoperatively and, therefore, improves the operative risk.

II The Surgical Patient with Cardiac Disease

Perioperative cardiac mortality is the leading cause of death after anesthesia and surgery. Extensive research has focused on preoperative assessment of cardiac risk and prevention of postoperative complications.

A

American College of Cardiology (ACC)/American Heart Association (AHA) Guidelines (2002) (Tables 3-2 and 3-3; Fig. 3-1)

An ACC/AHA consensus committee has developed a stepwise strategy to estimate coronary risk related to noncardiac surgery. This approach relies on an assessment of clinical markers of risk before coronary evaluation and treatment, functional capacity, and surgery -specific risk.

Several findings from the consensus committee follow.

Perioperative and long-term risk is increased in patients with poor exercise tolerance, i.e., unable to reach a 4-MET (Metabolic Equivalents of Exercise, called METS) demand during most activities.

Patients with moderate or excellent functional capacity are at low risk for cardiac complications in the

setting of intermediate risk surgery.

Patients with a poor functional capacity or those who have only a moderate functional capacity and are facing high-risk surgery should be considered for further noninvasive testing.

A recent myocardial infarction (MI) within the prior 30 days is a major risk factor for perioperative cardiac complication. A history of an MI more than 30 days before noncardiac surgery is an intermediate risk factor.

Post -MI stress test without reversible ischemia suggests a lower risk of a perioperative MI than if significant inducible ischemia is identified.

In the patient who has undergone a coronary revascularization procedure, it is suggested (but not proved in a controlled, randomized fashion) that coronary artery revascularization may reduce the risk of cardiac complication before vascular surgery. This benefit is probably present in the patient who has undergone complete coronary revascularization 6 months to 5 years before his or her noncardiac surgery and has no symptoms of myocardial ischemia with physical activity greater than 4 METs. Noncardiac surgery should probably be delayed for several days after a coronary angioplasty.

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TABLE 3-2 Cardiac Risk* Stratification for Noncardiac Surgical Procedures

*Combined incidence of cardiac death and nonfatal myocardial infarction.

Do not generally require further preoperative cardiac testing.

From Eagle KA, Berger PB, Calkins H, et al. ACC/AHA guideline update for perioperative cardiovascular evaluation for noncardiac surgery: a report of the American College of Cardiology/American Heart Association Task Force on Practice Guidelines (Committee to Update the 1996 Guideline on Perioperative Evaluation for Noncardiac Surgery). 2002. American College of Cardiology website. http://www.acc.org/quality and science/clinical/guidelines/perio/clean/perio_index.htm (Accessed December 15, 2006).

Noninvasive assessment of myocardial perfusion by exercise or pharmacologic stress testing (e.g., radionuclide myocardial imaging, stress echocardiography, dobutamine echocardiography) in conjunction with clinical predictors is helpful in risk assessment of the intermediate -risk patient.

Low-risk patients are younger than 70 years of age; they are physically active; and they have none of the following risk factors: angina, congestive heart failure, MI, diabetes, or ventricular ectopy. No preoperative ischemia testing is necessary; surgery can proceed.

Intermediate -risk patients have one or two of the risk factors in the low -risk category or live a sedentary lifestyle. Noninvasive assessment of myocardial perfusion should be done via exercise or via pharmacologic methods if the patient is unable to exercise.

If no ischemia is present , surgery is recommended.

If myocardial ischemia is present , the risk should be determined based on the extent of myocardium that is at risk for ischemia.

High-risk patients have three or more risk factors noted in the low -risk category or they have angina with daily activity, progressive angina, angina at rest, or a recent MI. Options depend on the patient's medical status.

Cardiac catheterization to define the coronary anatomy and to perform a revascularization procedure can be undertaken, if indicated, before vascular surgery.

A lower-risk vascular surgical procedure can be selected (e.g., axillofemoral bypass in a patient with aortoiliac disease).

Surgery can proceed, and the patient can be treated with parenteral antianginal therapy while being followed with invasive hemodynamic monitoring.

B Anesthesia principles

All inhaled general anesthetic agents are myocardial depressants.

Myocardial depression is usually minimized by reflex sympathetic response. For example, when nitrous oxide is administered, the systemic blood pressure usually remains unchanged, despite myocardial depression, as a result of reflex peripheral vasoconstriction.

Halothane is also a peripheral vasodilator. Myocardial depression and vasodilatation may result in hypotension, which may be further exaggerated if the patient is hypovolemic or is taking vasodilators.

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TABLE 3-3 Clinical Predictors of Increased Perioperative Cardiovascular Risk

(Myocardial Infarction, Congestive Heart Failure, Death)

Major

Unstable coronary syndromes

Recent myocardial infarction*with evidence of important ischemic risk by clinical symptoms of noninvasive study

Unstable or severe angina (Canadian class III or IV)‡

Decompensated congestive heart failure

Significant arrhythmias

High-grade atrioventricular block

Symptomatic ventricular arrhythmias in the presence of underlying heart disease

Supraventricular arrhythmias with uncontrolled ventricular rate

Severe valvular disease

Intermediate

Mild angina pectoris (Canadian class I or II)

Prior myocardial infarction by history or pathologic Q waves Compensated or prior congestive heart failure

Diabetes mellitus

Minor

Advanced age

Abnormal ECG (left ventricular hypertrophy, left bundle branch block, ST-T abnormalities)

Rhythm other than sinus (e.g., atrial fibrillation)

Low functional capacity (e.g., inability to climb one flight of stairs with a bag of groceries)

History of stroke

Uncontrolled systemic hypertension

ECG = electrocardiogram.

*The American College of Cardiology National Database Library defines a recent MI as greater than 7 days but less than or equal to 1 month (30 days).

May include “stable” angina in patients who are unusually sedentary.

‡Campeau L. Grading of angina pectoris. Circulation. 1976;54:522–523. From Eagle KA, Berger PB, Calkins H, et al. ACC/AHA guideline update for perioperative cardiovascular evaluation for noncardiac surgery: a report of the

American College of Cardiology/American Heart Association Task Force on Practice Guidelines (Committee to Update the 1996 Guideline on Perioperative Evaluation for Noncardiac Surgery). 2002. American College of Cardiology website. http://www.acc.org/quality and science/clinical/guidelines/perio/clean/perio_index.htm (Accessed December 15, 2006).

Regional and general anesthesia are associated with the same cardiac morbidity and mortality.

Exceptions follow.

The elderly patient undergoing inguinal hernia repair. Local anesthesia has been found to be associated with a lower risk of cardiovascular complication than regional or general anesthesia.

The patient with a history of congestive heart failure. Regional anesthesia is associated with a lower incidence of perioperative congestive heart failure.

Advantages of regional anesthesia in the cardiac patient follow.

Less myocardial or respiratory depression occurs than with general anesthesia.

Autonomic stimulation, which may accompany endotracheal intubation, is avoided.

Disadvantages of regional anesthesia in the cardiac patient include the following:

The awake patient may become anxious , which increases circulating catecholamines and can cause myocardial ischemia to develop.

Spinal anesthesia may result in vasodilatation and hypotension.

A patient with a “fixed” cardiac output (i.e., severe aortic stenosis, severe left ventricular dysfunction) may be unable to compensate.

Vasodilatation may also be harmful in the patient dependent on preload (e.g., the patient with severe pulmonary hypertension).

Recent data suggest that intensive perioperative and postoperative epidural analgesia may be associated with decreased postoperative myocardial ischemia and improved outcome. The mechanism is unclear but may involve a blunting of the sympathetic response to operative stress.

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FIGURE 3-1 ASS/AHA risk stratification strategy. (From the

American College for Cardiology/American Heart Association Task Force Report: guidelines for perioperative cardiovascular evaluation for noncardiac surgery. J Am Coll Cardiol. 1996;27:910–948.

)

C Pre-existing cardiovascular disease

Hypertension

Diastolic blood pressure greater than or equal to 110 mm Hg is a risk factor for the development of cardiac complications. If possible, surgery should be delayed if the patient with cardiovascular disease presents with preoperative diastolic blood pressure ≥110 mm Hg.

Patients with hypertension have a 25% incidence of either hypotension or an exacerbation of hypertension during the perioperative period.

The risk of a perioperative MI is increased if, during surgery, the blood pressure decreases by 50% at any time or by 33% for 10 minutes or longer.

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Angina (Canadian Cardiovascular Society class designations)

Class 1 or class 2 angina (chronic stable angina) is not a risk factor for perioperative cardiac complications.

Class 3 angina (angina walking up one flight of stairs or two blocks) is a cardiac risk factor and poses a risk similar to sustaining an MI during the 6 months before surgery.

Class 4 angina (angina on any exertion) indicates twice the risk of class 3 angina.

For patients who are well maintained on an antianginal regimen, care must be taken to ensure effective antianginal therapy in the perioperative period.

Myocardial infarction

The ACC/AHA consensus guidelines assign a history of MI or pathologic Q waves on the preoperative electrocardiogram (ECG) as intermediate -risk predictors and a recent MI (within the prior 30 days) as a major predictor of perioperative cardiac risk.

The patient who has undergone a coronary revascularization procedure may have a reduced risk of cardiac complications before vascular or other major surgery. However, this suggestion has not been proven by randomized controlled trials.

Patients with prior coronary artery bypass grafting (CABG) or percutaneous transluminal coronary angioplasty (PTCA) are subject to further coronary artery disease involving their native coronary arteries as well as bypass grafts.

Saphenous vein bypass occlusion rates are 12%–20% at 1 year, 20%–30% at 5 years, and 40%–50% at 10 years after CABG.

The incidence of coronary restenosis after a PTCA is 25%–35% at 6 months.

Most perioperative MIs occur during the first 4–5 postoperative days, with a peak incidence on days 1 and 2. A mortality rate of up to 69% has been reported.

Postoperative MIs are typically not associated with anginal pain but rather with new -onset congestive heart failure, arrhythmias, or confusion.

Congestive heart failure

Congestive heart failure is a risk factor for perioperative cardiac complications. Patients with a prior history but no preoperative clinical evidence of heart failure have a 6% incidence of perioperative pulmonary edema compared with a 16% incidence in patients found to have clinical or radiographic evidence of heart failure preoperatively.