Before surgery: Have you done enough to mitigate risk?

CASE Charlie H, an elderly man who has been your patient for more than 10 years, is scheduled for inguinal hernia repair, and has come in for a preoperative evaluation. Based on his medical history and a physical examination, you identify several risk factors for surgical complications: a low functional capacity (<4 METS), obesity (BMI=39), advanced age (70 years), and type 2 diabetes (well controlled). What should you write in your consultation note about Charlie’s perioperative risks, and what interventions should you institute—or recommend—to mitigate his risk?

A preoperative consult, a service that family physicians are well positioned to provide, requires a thorough and systematic approach. But because of time pressures—as well as a dearth of perioperative templates, guidelines, and checklists—a cursory history and physical exam often takes the place of a comprehensive evaluation.

A thorough medical history is the most valuable tool of a physician doing a preop consult, but a comprehensive evaluation also involves the assessment of perioperative risk factors, ancillary tests to consider, and interventions to recommend to mitigate risks. Although various published guidelines address specific systems, there are few places where family physicians can find a complete toolkit. The text and tables that follow, which form the core of a comprehensive resource initially compiled to help our residents conduct clear and effective preoperative consults, will help you safeguard your patients.

A system-by-system review starts with the heart

The vast majority of perioperative problems fall into a handful of categories: cardiac, pulmonary, renal, infectious, and hematologic complications (TABLE 1). When a surgeon requests a preoperative evaluation, however, the patient’s cardiac status is generally the primary concern. This is also the portion of the preop consult with the most formally structured guidelines; those issued by the American College of Cardiology and American Heart Association (ACC/AHA) are the most widely used.¹ Initially based primarily on expert opinion, the ACC/AHA guidelines are increasingly evidence-based (http://circ.ahajournals.org/cgi/reprint/CIRCULATIONAHA.109.192690).^1,2 These guidelines address the evaluation of patients for noncardiac surgery. Both cardiac surgery and emergent operations are beyond the scope of the guidelines, and are not addressed here.

Patients with unstable coronary syndromes—eg, unstable angina or myocardial infarction (MI) within the past 30 days, decompensated heart failure (HF), significant arrhythmias, or severe valvular disease—face an increased risk of perioperative morbidity and mortality. To reduce the risk, such patients require optimization of the underlying condition before undergoing elective surgery.¹

Stable ischemic heart disease, compensated HF, diabetes, chronic renal failure/insufficiency (CRF), cerebrovascular disease, and poor functional capacity (defined as <4 metabolic equivalents [METS]) in an asymptomatic patient also increase the risk of complications, but to a lesser degree. If a patient has coronary artery disease, evidence of ischemia on preoperative testing, or more than 1 of these clinical risk factors, surgery may proceed. Keep in mind, though, that the ACC/AHA guidelines suggest that the use of a beta-blocker, titrated to control heart rate and blood pressure, is reasonable in intermediate- or high-risk procedures (TABLE 1).^1,3,4

Is additional cardiac testing necessary? Whether you’re assessing for cardiac status or other risks, for that matter, evidence supports the use of ancillary testing in only a small minority of surgical patients. A general rule of thumb—regardless of the system you’re assessing—is to consider adjunctive testing only if the outcome has the potential to alter patient management. Thus, exercise stress testing or resting electrocardiography (EKG), among other tests, may be considered on an individual basis (TABLE 2), but studies have failed to demonstrate improved outcomes with added testing of cardiac status on a routine basis.^5,6

Evidence is insufficient to make a firm recommendation regarding additional cardiac testing, even for patients with more than 3 clinical risk factors. Nonetheless, the ACC/AHA guidelines favor the use of adjunctive testing in such cases, especially for patients who are candidates for high-risk procedures, such as vascular surgery.¹

What’s the local standard of care? Studies to determine when further testing is beneficial and which tests would benefit which patients are ongoing. In the absence of definitive findings, it behooves primary care physicians to familiarize themselves with the practices and preferences of the cardiologists and anesthesiologists at the facility where the surgery will be performed and to follow the local standard of care.

 

TABLE 1
Identifying—and minimizing—perioperative risk

Patient-specific risk factors	Procedure-specific risk factors	Risk reduction recommendations
Cardiac
Major risks • Decompensated HF • Severe valve disease • Significant arrhythmia • Unstable coronary syndrome Other cardiovascular risks • Cerebrovascular disease • CRF or AKI • Compensated/prior HF • Diabetes • Functional capacity <4 METS • Ischemic heart disease	Vascular surgery	• Optimize treatment of underlying conditions • Consider beta-blockers perioperatively1,3,4 • Consider adjunctive testing if results could alter patient management
Pulmonary
• Acute URI • Requiring assistance with ADLs • Age >60 years • Elevated BUN (>21 mg/dL) • COPD • HF • Hypoalbuminemia (<35 g/L) • Presence of any systemic disease	• Emergency surgery • General anesthesia • Surgery >3 h • Abdominal, head or neck, thoracic, or vascular surgery • Neurosurgery	• Postop incentive spirometry • Postop nasogastric tube • Consider intraoperative use of LMA • Smoking cessation (30 days preoperatively)28
Renal
• Age >60 years • CRF (especially with creatinine >2.1 mg/dL) • Diabetes (especially insulin-dependent) • HF • Jaundice	• Aortic or cardiovascular surgery • Liver transplantation	• Ensure preoperative euvolemia and good osmolar status • Minimize exposure to nephrotoxins • Avoid perioperative hypotension (maintain MAP >65 mm Hg) • Consider preoperative dialysis if GFR <15 mL/min14
Infectious
• Advanced age • Corticosteroid use • Hyperglycemia • Hypoalbuminemia • Immunocompromised • Malnutrition/obesity • Peripheral vascular disease • Postoperative incontinence • Preexisting infection • Prior radiation therapy • Smoking	• Blood transfusion • Surgery >3 h • Perioperative hypothermia • Perioperative hypoxia • Preoperative shaving • Prolonged preoperative hospital stay	• Optimize diabetes management (HbA1c <7); tight perioperative glycemic control • Treat preexisting infections • Provide nutritional supplementation (7-14 days preoperatively) • Smoking cessation (30 days preoperatively)28
Hematologic: Perioperative bleeding
• Collagen vascular disease • GI or urogenital blood loss • Heavy or prolonged menses • Hematologic disease • Hemophilia or other inherited disorder • History of easy bruising or bleeding • Hypersplenism • Liver or renal disease • Severe bleeding after dental extraction, other surgery, or childbirth • Physical findings suggestive of purpura, hematoma, jaundice, or cirrhosis • Use of medications that affect hemostasis	• Minimal risk/JHSRCS 1 (eg, breast biopsy, carpal tunnel procedure, cataract surgery) • Mild risk/JHSRCS 2 (eg, laparoscopy, arthroscopy, inquinal hernia repair) • Moderate risk/JHSRCS 3 (eg, open abdominal procedure, arthroplasty) • Significant risk/JHSRCS 4 (eg, open thoracic surgery, major vascular/skeletal procedure)	• Optimize treatment of preexisting conditions • Discontinue antihemostatic medications, if medically feasible • Consider autologous blood banking
Hematologic: Perioperative anemia
• Hemoglobinopathies • Preexisting iron deficiency anemia • Preexisting pernicious anemia	• Risk of bleeding based on type of surgery (see Perioperative bleeding, above)	• Correct anemia prior to surgery • Consider preoperative erythropoietin • Avoid preoperative transfusion
Hematologic: Venous thromboembolism
• Acute medical illness • Age (older) • Cancer (active or occult); cancer therapy • Estrogen/SERMs • Erythropoiesis-stimulating agents • Immobility • IBD • Lower-extremity paresis • Myeloproliferative disorders • Nephrotic syndrome • Obesity • Paroxysmal nocturnal hemoglobinuria • Pregnancy/postpartum • Previous VTE • Smoking • Thrombophilia • Venous compression	• Cardiothoracic surgery • Central venous catheterization • Major surgery (general, gynecologic, orthopedic, peripheral vascular, or urologic) • Neurosurgery • Trauma	• Ensure early, aggressive mobilization • Provide mechanical prophylaxis • Consider chemoprophylaxis
ADL, activities of daily living; AKI, acute kidney injury; BUN, blood urea nitrogen; COPD, chronic obstructive pulmonary disease; CRF, chronic renal failure/insufficiency; GFR, glomerular filtration rate; GI, gastrointestinal; HbA1c, hemoglobin A1c; HF, heart failure; IBD, inflammatory bowel disease; JHSRCS, Johns Hopkins Surgical Risk Classification System; LMA, laryngeal mask airway; MAP, mean arterial pressure; METS, metabolic equivalents; SERMs, selective estrogen receptor modulators; URI, upper respiratory infection; VTE, venous thromboembolism.

TABLE 2
When should you order these ancillary tests?*

Albumin† For at-risk populations9
BUN, creatinine, electrolytes For at-risk subpopulations21
Chest x-ray It depends. It is not used routinely for predicting risk but may be appropriate for patients with previous diagnosis of COPD or asthma.9
CBC, platelets Do not order routinely; check hemoglobin if procedure increases risk for bleeding.
Coagulation studies Do not order routinely.35,36
Echocardiogram It is reasonable to order for patients with dyspnea of unknown origin, history of HF and worsening dyspnea, or other change in clinical status and may be considered for patients with previously documented cardiomyopathy.1
EKG Vascular surgery: Order for patients with ≥1 clinical risk factors; it is also reasonable for patients with no clinical risk factors.1Intermediate-risk procedure: Order for patients with CHD, PAD, or CVD and consider for patients with ≥1 clinical risk factors.1
Exercise stress-testing Order for patients with active cardiac conditions; it is reasonable for vascular surgery candidates with ≥3 clinical risk factors and poor functional capacity and may be considered for patients undergoing vascular or intermediate-risk procedure who have 1-2 clinical risk factors and poor functional capacity.1
Spirometry, pulmonary-function testing Do not order routinely for predicting risk, but may be appropriate for patients with previous diagnosis of COPD or asthma.9
Urinalysis Order routinely.20
BUN, blood urea nitrogen; CBC, complete blood count; CHD, coronary heart disease; COPD, chronic obstructive pulmonary disease; CVD, cardiovascular disease; EKG, electrocardiography; HF, heart failure; PAD, peripheral artery disease.
*Most commonly recommended ancillary tests for which there are at least minimal data to suggest the validity of the opinion-based recommendation. Answers are opinion-based, not evidence-based. With the exception of albumin testing, the tests listed here are lacking in patient-oriented evidence of benefit from routine use.
† Routine testing of albumin levels is evidence-based.

 

Identify pulmonary risks with help from ACP
Postoperative pulmonary complications are as prevalent as cardiac complications, and contribute equally to morbidity, mortality, and length of stay. But pulmonary complications are better predictors of long-term mortality after surgery.⁷

There are several well-validated risk factors for increased perioperative pulmonary morbidity and mortality—HF, chronic obstructive pulmonary disease (COPD), advanced age, and the need for assistance with activities of daily living among them. In addition to identifying patient-specific risk factors, knowledge of the type of surgery planned will provide insight into procedure-specific risk factors (TABLE 1). The approach to the surgical pulmonary patient is addressed in an American College of Physicians (ACP) guideline published in 2006 and available at http://www.annals.org/content/144/8/575.full.pdf+html.⁷

What tests to consider? The ACP guideline is notable not only for its recommendations, but for the things that are not recommended but may nevertheless be considered the standard of care in some locales. Chest radiography and spirometry are 2 such examples. Although these tests may be appropriate on an individual basis for patients with a previous diagnosis of COPD or asthma, their routine use is of little value—and the ACP does not recommend them as part of a standard preop evaluation.⁷ Some laboratory tests may aid in risk stratification, however.

A serum albumin level <35 g/L is strongly associated with postop pulmonary complications.⁸ Checking levels in all patients suspected of hypoalbuminemia, including any patient with 1 or more pulmonary risk factors, is reasonable for a physician performing a preoperative evaluation. Consider checking blood urea nitrogen (BUN) levels, as well. Uremia (BUN >21 mg/dL) is also associated with increased pulmonary complications, although not as strongly as hypoalbuminemia.

Postpone or proceed? Acute conditions are another key consideration. An upper respiratory infection (URI) increases the risk of postoperative pulmonary complications, especially in children.^9,10 A simple algorithm offers guidance in deciding when to postpone surgery in pediatric patients with a URI:⁹

Recommend that it be delayed if the procedure involves general anesthesia and 1 or more of the following risk factors is present: asthma, a history of prematurity, copious secretions, a parent who smokes, planned use of an endotracheal tube, or a procedure involving the airway.

Surgery can proceed if symptoms of the infection are mild, general anesthesia is not required, or a risk/benefit analysis supports it. Considerations include the urgency of the procedure, whether the surgery has previously been postponed, the comfort level of the clinicians involved, and the distance the family must travel for the procedure.¹¹

If you recommend that surgery proceed as planned, suggest perioperative interventions to mitigate risk. Recommend that a laryngeal mask airway be used, if needed, in place of an endotracheal tube; that pulse oximetry monitoring occur; that good hydration and humidification of air be provided; and that the patient receive anticholinergic agents for secretions.

Other measures that have been shown to be effective in reducing perioperative pulmonary complications include deep breathing exercises (incentive spirometry) and the use of a nasogastric tube for those with postoperative emesis, intolerance of oral intake, or symptomatic abdominal distension.⁷ If your patient has risk factors for pulmonary complications, include a recommendation for a postop nasogastric tube in your preop consultation note. However, newer data indicating that patients had fewer pulmonary complications, a more rapid return of normal bowel function, no increased discomfort, and no increase in anastomotic leaks without a nasogastric tube^12,13 may lead to guideline revision.

A scoring system helps evaluate renal risk
Patients with CRF face increased risk of perioperative morbidity and mortality. But as long as the glomerular filtration rate (GFR) is >25 mL/min—which is only 25% of normal—surgery is generally well tolerated. As GFR drops to 10 to 15 mL/min, the rate of surgical complications rises rapidly, reaching 55% to 60%. For such patients, preoperative dialysis is worth considering.¹⁴

Postoperative acute kidney injury (AKI), as acute renal failure is now known,¹⁵ is associated with a 58% mortality rate.¹⁶ Fortunately, this complication develops in only about 1% of surgical patients.¹⁷ Both patient-specific risk factors (CRF, with creatinine >2.1 mg/dL; HF; diabetes, particularly being insulin dependent; age >60 years; jaundice) and procedure-specific risks (aortic, cardiovascular, or liver transplant surgery) help predict which surgical candidates face the highest risk.^16,18,19 Thakar et al have developed a scoring system to identify those at greatest risk for AKI.²⁰ (See “Cardiovascular surgery and acute kidney injury: Scoring the risk” at www.jfponline.com by clicking on “Before surgery: Have you done enough to mitigate risk?” and scrolling to the end.)

 

Minimize renal complications. Helping patients achieve good intravascular volume and osmolar status preoperatively will reduce their risk of renal complications. Other prophylactic measures: Minimize exposure to nephrotoxins (eg, nonsteroidal anti-inflammatory drugs or contrast media) to the extent possible. Consider evaluating the serum electrolyte and creatinine levels of patients with multiple risk factors to determine whether they can safely undergo surgery; some experts suggest preoperative urinalysis, as well.¹⁸

Patients with end-stage renal disease have very high perioperative morbidity.²¹ They are at increased risk for hyperkalemia, infection, hyper- and hypotension, bleeding, arrhythmias, and clotted fistulas, in descending order of incidence.¹⁸ Preoperative planning, including the need for dialysis before surgery, is necessary to manage these risks.

Risk of postop infection: Focusing on the foreseeable
Postoperative infections, both at the surgical site and remote from the incision, are a significant cause of morbidity and mortality. Pneumonia is among the most prominent remote infections associated with surgery,²² and early ambulation, deep breathing exercises, and tight glycemic control can greatly decrease the risk.

Surgical site infection (SSI) remains an important concern, occurring in 37% of cases.²³ Risk factors include hyperglycemia, malnutrition, perioperative steroid use, preexisting infections, tobacco smoking, peripheral vascular disease, advanced age, radiation therapy, blood transfusions, prolonged preoperative stay, preoperative shaving, hypothermia, hypoxia, length of operation, and postoperative incontinence.²⁴ While many of these risk factors are dependent on interventions in the operating room and recovery room or during subsequent hospitalization, it is important to address foreseeable risks as part of the preoperative evaluation.

Glycemic control is crucial. Perhaps the most well-documented risk for SSI is hyperglycemia—a common problem among hospitalized patients.¹⁶ Hyperglycemia impairs leukocyte and complement function,^25,26 thereby increasing risk of infectious complications. Tight glycemic control in the surgical patient, especially on the surgical intensive care unit, has been associated with improved outcomes.²⁷

Identify the presence of diabetes in the preoperative consult note, and adjust the patient’s medication regimen as needed, to help him or her achieve optimal glycemic control. In some cases, it may be necessary to delay nonurgent surgery until the patient achieves adequate control.

Malnutrition is another risk factor for SSI. For patients who are undernourished or morbidly obese, checking serum albumin levels may be beneficial. Supplementation for 1 to 2 weeks prior to surgery may decrease the risk of infection for patients who are undernourished;²⁸ for obese patients, weight loss is beneficial. Although significant preoperative weight loss may not be possible, it is important to list an elevated body mass index as a risk factor in the consultation note.

Corticosteroids, used to treat conditions such as COPD, inflammatory bowel disease, allergies, and autoimmune disorders, are another risk factor for perioperative infection. In addition to their effect on glycemic control, corticosteroids directly suppress the immune system. Whenever possible, they should be discontinued preoperatively. If this is not possible, call attention to the patient’s use of corticosteroids in the consultation note.

Preexisting infection presents the possibility of the spread of organisms to the surgical site and, whenever possible, surgery should be postponed until the infection resolves. If the patient has a history of prior infection or colonization with methicillin-resistant Staphylococcus aureus, be sure to include that in the consultation note, as well.

Leukocyte-containing blood product transfusions are associated with a 2-fold increase in some postop infectious complications.^29-31 This is in addition to the well-known risk of bloodborne pathogens associated with transfusions, and is yet another reason to avoid perioperative transfusions whenever possible.

 

Smoking impairs tissue oxygenation, which delays healing and increases risk of infection. Smoking cessation should be strongly encouraged at every preoperative consultation. Recommend nicotine replacement therapy even for patients who aren’t willing to quit altogether; point out that giving up cigarettes for just 30 days (or more) before surgery can decrease the likelihood of complications.²⁸

In addition to these identified risk factors, anything that compromises the immune status increases the risk of infection. Alcohol or drug abusers, chronic pain patients, transplant recipients, cancer patients taking immunosuppressants, postsplenectomy patients, and patients with HIV are all at increased risk. Identify any such conditions during your preoperative evaluation, and be sure to include them in your communication with the surgical team.

A common request in preop consults relates to bacterial endocarditis prophylaxis. Only an extremely small number of cases of infective endocarditis occur with dental procedures, however, so the benefits of antibiotic prophylaxis would be minimal, even if the prophylactic therapy were 100% effective.³² As a result, the ACC/AHA guidelines recommend prophylaxis for dental procedures only for patients with underlying cardiac conditions associated with the highest risk of adverse outcome from infective endocarditis. Administration of antibiotics solely to prevent endocarditis is not recommended for patients undergoing genitourinary or gastrointestinal tract procedures.³²

Hematologic evaluation: Address risks of bleeding, clotting
Historically, a variety of tests have been employed in an effort to identify patients at risk for bleeding complications prior to surgery—including prothrombin time, partial thromboplastin time, platelet count, and bleeding time, or platelet function. While highly reproducible, automated, and inexpensive when considered individually, the cumulative cost of routine use of these tests is high.³³

A recent review of the literature indicates that, for surgical patients without synthetic liver dysfunction or a history of oral anticoagulant use, routine testing is of little value in the assessment of bleeding risk.³⁴ Patients with a negative bleeding history do not require routine coagulation screening prior to surgery.³⁵

Instead, use the medical history to identify risk factors for bleeding. These include excessive bruising, nosebleeds, prolonged bleeding after cuts, bleeding >3 minutes after brushing teeth, and heavy or prolonged menses (TABLE 1). Patients with a past medical history of liver disease; renal failure; hypersplenism; hematologic disease; collagen vascular disease; hemophilia or other inherited hemorrhagic disorder; gastrointestinal or urogenital blood loss; and severe bleeding after dental extraction, other surgery, or childbirth are also at heightened risk, as are those who take medications that affect hemostasis. Physical findings suggestive of risk include purpura, hematoma, jaundice, and signs of cirrhosis.³⁴

While laboratory testing is only appropriate to confirm those at risk in the subpopulation selected by the history and physical, here, as with other adjunctive testing, it is important to consider local standards and the preferences of the surgeon who requested the preop consult.

Treat anemia. Preoperative anemia is linked to adverse outcomes in surgical patients,³⁶ although it is not clear whether the anemia itself or the perioperative transfusions associated with the condition are at the root of the problem.³⁷ Macrocytic anemia may require treatment with vitamin B₁₂ and folate; iron deficiency anemia is treated with iron. Some physicians also recommend the use of erythropoietin starting 3 weeks prior to surgery for patients with normocytic anemia with hemoglobin <13 g/dL.^38,39

Thromboembolism risk. Excessive clotting is responsible for more perioperative complications than excessive bleeding. There is a high prevalence of venous thromboembolism (VTE) among surgical patients, with both patient- and procedure-specific risk factors. Although a variety of coagulopathies increase the baseline risk for VTE, routine laboratory screening of the general surgical population for thrombophilia is not recommended.^34,35

When risk factors are present based on both the patient’s medical history and the type of procedure, prophylactic measures may be needed (TABLE 3). Options include mechanical prophylaxis (graduated compression stockings and intermittent pneumatic devices) and chemoprophylaxis. Recommended for high-risk cases, such as patients undergoing orthopedic surgery that precludes early mobilization, chemoprophylaxis options include low-molecular-weight heparin, low-dose unfractionated heparin, fondaparinux (a synthetic factor Xa inhibitor), and vitamin K antagonists such as warfarin.⁴⁰ Aspirin alone is not recommended, as it has not been found to be an effective prophylaxis for VTE.

CASE After following this system-by-system review of your patient, Charlie H, you identify and explicitly communicate the following risk factors in your consultation note:

• Cardiovascular: type 2 diabetes, low functional capacity
• Pulmonary: advanced age
• Renal: advanced age
• Infectious: type 2 diabetes, advanced age, BMI=39
• Hematologic: advanced age, obesity

Based on these findings, you develop the following plan for Charlie H, detailed in the consultation note you submit to the surgical team:

 

• Continue home diabetes medications perioperatively, supplemented with a basal-bolus insulin regimen.
• Initiate incentive spirometry postoperatively; use an NG tube if postoperative nausea and vomiting occur.
• Maintain MAP >65 mm Hg.
• Institute aggressive early ambulation and use of graduated compression stockings for DVT prophylaxis.
  Submitted by ___________ on ________.

TABLE 3
Perioperative thromboembolism: Risk and prophylaxis

DVT/VTE risk40	Prophylaxis recommendations
Low (<10%) • Mobile patients40 • Minimal patient-specific risk factors • Surgery <30 min41	• Early mobilization
Medium (10%-40%) • Most general, gynecologic, or urologic procedures40 • Surgery >30 min41 • Additional patient-specific risk factors • Moderate-risk procedure with high risk of bleeding35	• Chemoprophylaxis (LMWH, LDUH, Fpx) • Mechanical prophylaxis GCS; may consider adding IPD)
High (40%-80%) • Trauma, major surgery40 • Either patient or procedure is high risk for VTE and patient is at high risk of bleeding	• Chemoprophylaxis (LMWH, Fpx, VKA) • Mechanical prophylaxis (GCS and IPD)
DVT, deep vein thrombosis; Fpx, fondaparinux; GCS, graduated compression stockings; IPD, intermittent pneumatic device; LDUH, low-dose unfractionated heparin; LMWH, low-molecular-weight heparin; VKA, vitamin K antagonists; VTE, venous thromboembolism.

CORRESPONDENCE Mark K. Huntington, MD, PhD, FAAFP, Center for Family Medicine, 1115 East Twentieth Street, Sioux Falls, SD 57105; [email protected]

CASE Charlie H, an elderly man who has been your patient for more than 10 years, is scheduled for inguinal hernia repair, and has come in for a preoperative evaluation. Based on his medical history and a physical examination, you identify several risk factors for surgical complications: a low functional capacity (<4 METS), obesity (BMI=39), advanced age (70 years), and type 2 diabetes (well controlled). What should you write in your consultation note about Charlie’s perioperative risks, and what interventions should you institute—or recommend—to mitigate his risk?

A preoperative consult, a service that family physicians are well positioned to provide, requires a thorough and systematic approach. But because of time pressures—as well as a dearth of perioperative templates, guidelines, and checklists—a cursory history and physical exam often takes the place of a comprehensive evaluation.

A thorough medical history is the most valuable tool of a physician doing a preop consult, but a comprehensive evaluation also involves the assessment of perioperative risk factors, ancillary tests to consider, and interventions to recommend to mitigate risks. Although various published guidelines address specific systems, there are few places where family physicians can find a complete toolkit. The text and tables that follow, which form the core of a comprehensive resource initially compiled to help our residents conduct clear and effective preoperative consults, will help you safeguard your patients.

A system-by-system review starts with the heart

The vast majority of perioperative problems fall into a handful of categories: cardiac, pulmonary, renal, infectious, and hematologic complications (TABLE 1). When a surgeon requests a preoperative evaluation, however, the patient’s cardiac status is generally the primary concern. This is also the portion of the preop consult with the most formally structured guidelines; those issued by the American College of Cardiology and American Heart Association (ACC/AHA) are the most widely used.¹ Initially based primarily on expert opinion, the ACC/AHA guidelines are increasingly evidence-based (http://circ.ahajournals.org/cgi/reprint/CIRCULATIONAHA.109.192690).^1,2 These guidelines address the evaluation of patients for noncardiac surgery. Both cardiac surgery and emergent operations are beyond the scope of the guidelines, and are not addressed here.

Patients with unstable coronary syndromes—eg, unstable angina or myocardial infarction (MI) within the past 30 days, decompensated heart failure (HF), significant arrhythmias, or severe valvular disease—face an increased risk of perioperative morbidity and mortality. To reduce the risk, such patients require optimization of the underlying condition before undergoing elective surgery.¹

Stable ischemic heart disease, compensated HF, diabetes, chronic renal failure/insufficiency (CRF), cerebrovascular disease, and poor functional capacity (defined as <4 metabolic equivalents [METS]) in an asymptomatic patient also increase the risk of complications, but to a lesser degree. If a patient has coronary artery disease, evidence of ischemia on preoperative testing, or more than 1 of these clinical risk factors, surgery may proceed. Keep in mind, though, that the ACC/AHA guidelines suggest that the use of a beta-blocker, titrated to control heart rate and blood pressure, is reasonable in intermediate- or high-risk procedures (TABLE 1).^1,3,4

Is additional cardiac testing necessary? Whether you’re assessing for cardiac status or other risks, for that matter, evidence supports the use of ancillary testing in only a small minority of surgical patients. A general rule of thumb—regardless of the system you’re assessing—is to consider adjunctive testing only if the outcome has the potential to alter patient management. Thus, exercise stress testing or resting electrocardiography (EKG), among other tests, may be considered on an individual basis (TABLE 2), but studies have failed to demonstrate improved outcomes with added testing of cardiac status on a routine basis.^5,6

Evidence is insufficient to make a firm recommendation regarding additional cardiac testing, even for patients with more than 3 clinical risk factors. Nonetheless, the ACC/AHA guidelines favor the use of adjunctive testing in such cases, especially for patients who are candidates for high-risk procedures, such as vascular surgery.¹

What’s the local standard of care? Studies to determine when further testing is beneficial and which tests would benefit which patients are ongoing. In the absence of definitive findings, it behooves primary care physicians to familiarize themselves with the practices and preferences of the cardiologists and anesthesiologists at the facility where the surgery will be performed and to follow the local standard of care.

 

TABLE 1
Identifying—and minimizing—perioperative risk

Patient-specific risk factors	Procedure-specific risk factors	Risk reduction recommendations
Cardiac
Major risks • Decompensated HF • Severe valve disease • Significant arrhythmia • Unstable coronary syndrome Other cardiovascular risks • Cerebrovascular disease • CRF or AKI • Compensated/prior HF • Diabetes • Functional capacity <4 METS • Ischemic heart disease	Vascular surgery	• Optimize treatment of underlying conditions • Consider beta-blockers perioperatively1,3,4 • Consider adjunctive testing if results could alter patient management
Pulmonary
• Acute URI • Requiring assistance with ADLs • Age >60 years • Elevated BUN (>21 mg/dL) • COPD • HF • Hypoalbuminemia (<35 g/L) • Presence of any systemic disease	• Emergency surgery • General anesthesia • Surgery >3 h • Abdominal, head or neck, thoracic, or vascular surgery • Neurosurgery	• Postop incentive spirometry • Postop nasogastric tube • Consider intraoperative use of LMA • Smoking cessation (30 days preoperatively)28
Renal
• Age >60 years • CRF (especially with creatinine >2.1 mg/dL) • Diabetes (especially insulin-dependent) • HF • Jaundice	• Aortic or cardiovascular surgery • Liver transplantation	• Ensure preoperative euvolemia and good osmolar status • Minimize exposure to nephrotoxins • Avoid perioperative hypotension (maintain MAP >65 mm Hg) • Consider preoperative dialysis if GFR <15 mL/min14
Infectious
• Advanced age • Corticosteroid use • Hyperglycemia • Hypoalbuminemia • Immunocompromised • Malnutrition/obesity • Peripheral vascular disease • Postoperative incontinence • Preexisting infection • Prior radiation therapy • Smoking	• Blood transfusion • Surgery >3 h • Perioperative hypothermia • Perioperative hypoxia • Preoperative shaving • Prolonged preoperative hospital stay	• Optimize diabetes management (HbA1c <7); tight perioperative glycemic control • Treat preexisting infections • Provide nutritional supplementation (7-14 days preoperatively) • Smoking cessation (30 days preoperatively)28
Hematologic: Perioperative bleeding
• Collagen vascular disease • GI or urogenital blood loss • Heavy or prolonged menses • Hematologic disease • Hemophilia or other inherited disorder • History of easy bruising or bleeding • Hypersplenism • Liver or renal disease • Severe bleeding after dental extraction, other surgery, or childbirth • Physical findings suggestive of purpura, hematoma, jaundice, or cirrhosis • Use of medications that affect hemostasis	• Minimal risk/JHSRCS 1 (eg, breast biopsy, carpal tunnel procedure, cataract surgery) • Mild risk/JHSRCS 2 (eg, laparoscopy, arthroscopy, inquinal hernia repair) • Moderate risk/JHSRCS 3 (eg, open abdominal procedure, arthroplasty) • Significant risk/JHSRCS 4 (eg, open thoracic surgery, major vascular/skeletal procedure)	• Optimize treatment of preexisting conditions • Discontinue antihemostatic medications, if medically feasible • Consider autologous blood banking
Hematologic: Perioperative anemia
• Hemoglobinopathies • Preexisting iron deficiency anemia • Preexisting pernicious anemia	• Risk of bleeding based on type of surgery (see Perioperative bleeding, above)	• Correct anemia prior to surgery • Consider preoperative erythropoietin • Avoid preoperative transfusion
Hematologic: Venous thromboembolism
• Acute medical illness • Age (older) • Cancer (active or occult); cancer therapy • Estrogen/SERMs • Erythropoiesis-stimulating agents • Immobility • IBD • Lower-extremity paresis • Myeloproliferative disorders • Nephrotic syndrome • Obesity • Paroxysmal nocturnal hemoglobinuria • Pregnancy/postpartum • Previous VTE • Smoking • Thrombophilia • Venous compression	• Cardiothoracic surgery • Central venous catheterization • Major surgery (general, gynecologic, orthopedic, peripheral vascular, or urologic) • Neurosurgery • Trauma	• Ensure early, aggressive mobilization • Provide mechanical prophylaxis • Consider chemoprophylaxis
ADL, activities of daily living; AKI, acute kidney injury; BUN, blood urea nitrogen; COPD, chronic obstructive pulmonary disease; CRF, chronic renal failure/insufficiency; GFR, glomerular filtration rate; GI, gastrointestinal; HbA1c, hemoglobin A1c; HF, heart failure; IBD, inflammatory bowel disease; JHSRCS, Johns Hopkins Surgical Risk Classification System; LMA, laryngeal mask airway; MAP, mean arterial pressure; METS, metabolic equivalents; SERMs, selective estrogen receptor modulators; URI, upper respiratory infection; VTE, venous thromboembolism.

TABLE 2
When should you order these ancillary tests?*

Albumin† For at-risk populations9
BUN, creatinine, electrolytes For at-risk subpopulations21
Chest x-ray It depends. It is not used routinely for predicting risk but may be appropriate for patients with previous diagnosis of COPD or asthma.9
CBC, platelets Do not order routinely; check hemoglobin if procedure increases risk for bleeding.
Coagulation studies Do not order routinely.35,36
Echocardiogram It is reasonable to order for patients with dyspnea of unknown origin, history of HF and worsening dyspnea, or other change in clinical status and may be considered for patients with previously documented cardiomyopathy.1
EKG Vascular surgery: Order for patients with ≥1 clinical risk factors; it is also reasonable for patients with no clinical risk factors.1Intermediate-risk procedure: Order for patients with CHD, PAD, or CVD and consider for patients with ≥1 clinical risk factors.1
Exercise stress-testing Order for patients with active cardiac conditions; it is reasonable for vascular surgery candidates with ≥3 clinical risk factors and poor functional capacity and may be considered for patients undergoing vascular or intermediate-risk procedure who have 1-2 clinical risk factors and poor functional capacity.1
Spirometry, pulmonary-function testing Do not order routinely for predicting risk, but may be appropriate for patients with previous diagnosis of COPD or asthma.9
Urinalysis Order routinely.20
BUN, blood urea nitrogen; CBC, complete blood count; CHD, coronary heart disease; COPD, chronic obstructive pulmonary disease; CVD, cardiovascular disease; EKG, electrocardiography; HF, heart failure; PAD, peripheral artery disease.
*Most commonly recommended ancillary tests for which there are at least minimal data to suggest the validity of the opinion-based recommendation. Answers are opinion-based, not evidence-based. With the exception of albumin testing, the tests listed here are lacking in patient-oriented evidence of benefit from routine use.
† Routine testing of albumin levels is evidence-based.

 

Identify pulmonary risks with help from ACP
Postoperative pulmonary complications are as prevalent as cardiac complications, and contribute equally to morbidity, mortality, and length of stay. But pulmonary complications are better predictors of long-term mortality after surgery.⁷

There are several well-validated risk factors for increased perioperative pulmonary morbidity and mortality—HF, chronic obstructive pulmonary disease (COPD), advanced age, and the need for assistance with activities of daily living among them. In addition to identifying patient-specific risk factors, knowledge of the type of surgery planned will provide insight into procedure-specific risk factors (TABLE 1). The approach to the surgical pulmonary patient is addressed in an American College of Physicians (ACP) guideline published in 2006 and available at http://www.annals.org/content/144/8/575.full.pdf+html.⁷

What tests to consider? The ACP guideline is notable not only for its recommendations, but for the things that are not recommended but may nevertheless be considered the standard of care in some locales. Chest radiography and spirometry are 2 such examples. Although these tests may be appropriate on an individual basis for patients with a previous diagnosis of COPD or asthma, their routine use is of little value—and the ACP does not recommend them as part of a standard preop evaluation.⁷ Some laboratory tests may aid in risk stratification, however.

A serum albumin level <35 g/L is strongly associated with postop pulmonary complications.⁸ Checking levels in all patients suspected of hypoalbuminemia, including any patient with 1 or more pulmonary risk factors, is reasonable for a physician performing a preoperative evaluation. Consider checking blood urea nitrogen (BUN) levels, as well. Uremia (BUN >21 mg/dL) is also associated with increased pulmonary complications, although not as strongly as hypoalbuminemia.

Postpone or proceed? Acute conditions are another key consideration. An upper respiratory infection (URI) increases the risk of postoperative pulmonary complications, especially in children.^9,10 A simple algorithm offers guidance in deciding when to postpone surgery in pediatric patients with a URI:⁹

Recommend that it be delayed if the procedure involves general anesthesia and 1 or more of the following risk factors is present: asthma, a history of prematurity, copious secretions, a parent who smokes, planned use of an endotracheal tube, or a procedure involving the airway.

Surgery can proceed if symptoms of the infection are mild, general anesthesia is not required, or a risk/benefit analysis supports it. Considerations include the urgency of the procedure, whether the surgery has previously been postponed, the comfort level of the clinicians involved, and the distance the family must travel for the procedure.¹¹

If you recommend that surgery proceed as planned, suggest perioperative interventions to mitigate risk. Recommend that a laryngeal mask airway be used, if needed, in place of an endotracheal tube; that pulse oximetry monitoring occur; that good hydration and humidification of air be provided; and that the patient receive anticholinergic agents for secretions.

Other measures that have been shown to be effective in reducing perioperative pulmonary complications include deep breathing exercises (incentive spirometry) and the use of a nasogastric tube for those with postoperative emesis, intolerance of oral intake, or symptomatic abdominal distension.⁷ If your patient has risk factors for pulmonary complications, include a recommendation for a postop nasogastric tube in your preop consultation note. However, newer data indicating that patients had fewer pulmonary complications, a more rapid return of normal bowel function, no increased discomfort, and no increase in anastomotic leaks without a nasogastric tube^12,13 may lead to guideline revision.

A scoring system helps evaluate renal risk
Patients with CRF face increased risk of perioperative morbidity and mortality. But as long as the glomerular filtration rate (GFR) is >25 mL/min—which is only 25% of normal—surgery is generally well tolerated. As GFR drops to 10 to 15 mL/min, the rate of surgical complications rises rapidly, reaching 55% to 60%. For such patients, preoperative dialysis is worth considering.¹⁴

Postoperative acute kidney injury (AKI), as acute renal failure is now known,¹⁵ is associated with a 58% mortality rate.¹⁶ Fortunately, this complication develops in only about 1% of surgical patients.¹⁷ Both patient-specific risk factors (CRF, with creatinine >2.1 mg/dL; HF; diabetes, particularly being insulin dependent; age >60 years; jaundice) and procedure-specific risks (aortic, cardiovascular, or liver transplant surgery) help predict which surgical candidates face the highest risk.^16,18,19 Thakar et al have developed a scoring system to identify those at greatest risk for AKI.²⁰ (See “Cardiovascular surgery and acute kidney injury: Scoring the risk” at www.jfponline.com by clicking on “Before surgery: Have you done enough to mitigate risk?” and scrolling to the end.)

 

Minimize renal complications. Helping patients achieve good intravascular volume and osmolar status preoperatively will reduce their risk of renal complications. Other prophylactic measures: Minimize exposure to nephrotoxins (eg, nonsteroidal anti-inflammatory drugs or contrast media) to the extent possible. Consider evaluating the serum electrolyte and creatinine levels of patients with multiple risk factors to determine whether they can safely undergo surgery; some experts suggest preoperative urinalysis, as well.¹⁸

Patients with end-stage renal disease have very high perioperative morbidity.²¹ They are at increased risk for hyperkalemia, infection, hyper- and hypotension, bleeding, arrhythmias, and clotted fistulas, in descending order of incidence.¹⁸ Preoperative planning, including the need for dialysis before surgery, is necessary to manage these risks.

Risk of postop infection: Focusing on the foreseeable
Postoperative infections, both at the surgical site and remote from the incision, are a significant cause of morbidity and mortality. Pneumonia is among the most prominent remote infections associated with surgery,²² and early ambulation, deep breathing exercises, and tight glycemic control can greatly decrease the risk.

Surgical site infection (SSI) remains an important concern, occurring in 37% of cases.²³ Risk factors include hyperglycemia, malnutrition, perioperative steroid use, preexisting infections, tobacco smoking, peripheral vascular disease, advanced age, radiation therapy, blood transfusions, prolonged preoperative stay, preoperative shaving, hypothermia, hypoxia, length of operation, and postoperative incontinence.²⁴ While many of these risk factors are dependent on interventions in the operating room and recovery room or during subsequent hospitalization, it is important to address foreseeable risks as part of the preoperative evaluation.

Glycemic control is crucial. Perhaps the most well-documented risk for SSI is hyperglycemia—a common problem among hospitalized patients.¹⁶ Hyperglycemia impairs leukocyte and complement function,^25,26 thereby increasing risk of infectious complications. Tight glycemic control in the surgical patient, especially on the surgical intensive care unit, has been associated with improved outcomes.²⁷

Identify the presence of diabetes in the preoperative consult note, and adjust the patient’s medication regimen as needed, to help him or her achieve optimal glycemic control. In some cases, it may be necessary to delay nonurgent surgery until the patient achieves adequate control.

Malnutrition is another risk factor for SSI. For patients who are undernourished or morbidly obese, checking serum albumin levels may be beneficial. Supplementation for 1 to 2 weeks prior to surgery may decrease the risk of infection for patients who are undernourished;²⁸ for obese patients, weight loss is beneficial. Although significant preoperative weight loss may not be possible, it is important to list an elevated body mass index as a risk factor in the consultation note.

Corticosteroids, used to treat conditions such as COPD, inflammatory bowel disease, allergies, and autoimmune disorders, are another risk factor for perioperative infection. In addition to their effect on glycemic control, corticosteroids directly suppress the immune system. Whenever possible, they should be discontinued preoperatively. If this is not possible, call attention to the patient’s use of corticosteroids in the consultation note.

Preexisting infection presents the possibility of the spread of organisms to the surgical site and, whenever possible, surgery should be postponed until the infection resolves. If the patient has a history of prior infection or colonization with methicillin-resistant Staphylococcus aureus, be sure to include that in the consultation note, as well.

Leukocyte-containing blood product transfusions are associated with a 2-fold increase in some postop infectious complications.^29-31 This is in addition to the well-known risk of bloodborne pathogens associated with transfusions, and is yet another reason to avoid perioperative transfusions whenever possible.

 

Smoking impairs tissue oxygenation, which delays healing and increases risk of infection. Smoking cessation should be strongly encouraged at every preoperative consultation. Recommend nicotine replacement therapy even for patients who aren’t willing to quit altogether; point out that giving up cigarettes for just 30 days (or more) before surgery can decrease the likelihood of complications.²⁸

In addition to these identified risk factors, anything that compromises the immune status increases the risk of infection. Alcohol or drug abusers, chronic pain patients, transplant recipients, cancer patients taking immunosuppressants, postsplenectomy patients, and patients with HIV are all at increased risk. Identify any such conditions during your preoperative evaluation, and be sure to include them in your communication with the surgical team.

A common request in preop consults relates to bacterial endocarditis prophylaxis. Only an extremely small number of cases of infective endocarditis occur with dental procedures, however, so the benefits of antibiotic prophylaxis would be minimal, even if the prophylactic therapy were 100% effective.³² As a result, the ACC/AHA guidelines recommend prophylaxis for dental procedures only for patients with underlying cardiac conditions associated with the highest risk of adverse outcome from infective endocarditis. Administration of antibiotics solely to prevent endocarditis is not recommended for patients undergoing genitourinary or gastrointestinal tract procedures.³²

Hematologic evaluation: Address risks of bleeding, clotting
Historically, a variety of tests have been employed in an effort to identify patients at risk for bleeding complications prior to surgery—including prothrombin time, partial thromboplastin time, platelet count, and bleeding time, or platelet function. While highly reproducible, automated, and inexpensive when considered individually, the cumulative cost of routine use of these tests is high.³³

A recent review of the literature indicates that, for surgical patients without synthetic liver dysfunction or a history of oral anticoagulant use, routine testing is of little value in the assessment of bleeding risk.³⁴ Patients with a negative bleeding history do not require routine coagulation screening prior to surgery.³⁵

Instead, use the medical history to identify risk factors for bleeding. These include excessive bruising, nosebleeds, prolonged bleeding after cuts, bleeding >3 minutes after brushing teeth, and heavy or prolonged menses (TABLE 1). Patients with a past medical history of liver disease; renal failure; hypersplenism; hematologic disease; collagen vascular disease; hemophilia or other inherited hemorrhagic disorder; gastrointestinal or urogenital blood loss; and severe bleeding after dental extraction, other surgery, or childbirth are also at heightened risk, as are those who take medications that affect hemostasis. Physical findings suggestive of risk include purpura, hematoma, jaundice, and signs of cirrhosis.³⁴

While laboratory testing is only appropriate to confirm those at risk in the subpopulation selected by the history and physical, here, as with other adjunctive testing, it is important to consider local standards and the preferences of the surgeon who requested the preop consult.

Treat anemia. Preoperative anemia is linked to adverse outcomes in surgical patients,³⁶ although it is not clear whether the anemia itself or the perioperative transfusions associated with the condition are at the root of the problem.³⁷ Macrocytic anemia may require treatment with vitamin B₁₂ and folate; iron deficiency anemia is treated with iron. Some physicians also recommend the use of erythropoietin starting 3 weeks prior to surgery for patients with normocytic anemia with hemoglobin <13 g/dL.^38,39

Thromboembolism risk. Excessive clotting is responsible for more perioperative complications than excessive bleeding. There is a high prevalence of venous thromboembolism (VTE) among surgical patients, with both patient- and procedure-specific risk factors. Although a variety of coagulopathies increase the baseline risk for VTE, routine laboratory screening of the general surgical population for thrombophilia is not recommended.^34,35

When risk factors are present based on both the patient’s medical history and the type of procedure, prophylactic measures may be needed (TABLE 3). Options include mechanical prophylaxis (graduated compression stockings and intermittent pneumatic devices) and chemoprophylaxis. Recommended for high-risk cases, such as patients undergoing orthopedic surgery that precludes early mobilization, chemoprophylaxis options include low-molecular-weight heparin, low-dose unfractionated heparin, fondaparinux (a synthetic factor Xa inhibitor), and vitamin K antagonists such as warfarin.⁴⁰ Aspirin alone is not recommended, as it has not been found to be an effective prophylaxis for VTE.

CASE After following this system-by-system review of your patient, Charlie H, you identify and explicitly communicate the following risk factors in your consultation note:

• Cardiovascular: type 2 diabetes, low functional capacity
• Pulmonary: advanced age
• Renal: advanced age
• Infectious: type 2 diabetes, advanced age, BMI=39
• Hematologic: advanced age, obesity

Based on these findings, you develop the following plan for Charlie H, detailed in the consultation note you submit to the surgical team:

 

• Continue home diabetes medications perioperatively, supplemented with a basal-bolus insulin regimen.
• Initiate incentive spirometry postoperatively; use an NG tube if postoperative nausea and vomiting occur.
• Maintain MAP >65 mm Hg.
• Institute aggressive early ambulation and use of graduated compression stockings for DVT prophylaxis.
  Submitted by ___________ on ________.

TABLE 3
Perioperative thromboembolism: Risk and prophylaxis

DVT/VTE risk40	Prophylaxis recommendations
Low (<10%) • Mobile patients40 • Minimal patient-specific risk factors • Surgery <30 min41	• Early mobilization
Medium (10%-40%) • Most general, gynecologic, or urologic procedures40 • Surgery >30 min41 • Additional patient-specific risk factors • Moderate-risk procedure with high risk of bleeding35	• Chemoprophylaxis (LMWH, LDUH, Fpx) • Mechanical prophylaxis GCS; may consider adding IPD)
High (40%-80%) • Trauma, major surgery40 • Either patient or procedure is high risk for VTE and patient is at high risk of bleeding	• Chemoprophylaxis (LMWH, Fpx, VKA) • Mechanical prophylaxis (GCS and IPD)
DVT, deep vein thrombosis; Fpx, fondaparinux; GCS, graduated compression stockings; IPD, intermittent pneumatic device; LDUH, low-dose unfractionated heparin; LMWH, low-molecular-weight heparin; VKA, vitamin K antagonists; VTE, venous thromboembolism.

CORRESPONDENCE Mark K. Huntington, MD, PhD, FAAFP, Center for Family Medicine, 1115 East Twentieth Street, Sioux Falls, SD 57105; [email protected]

CASE Charlie H, an elderly man who has been your patient for more than 10 years, is scheduled for inguinal hernia repair, and has come in for a preoperative evaluation. Based on his medical history and a physical examination, you identify several risk factors for surgical complications: a low functional capacity (<4 METS), obesity (BMI=39), advanced age (70 years), and type 2 diabetes (well controlled). What should you write in your consultation note about Charlie’s perioperative risks, and what interventions should you institute—or recommend—to mitigate his risk?

A preoperative consult, a service that family physicians are well positioned to provide, requires a thorough and systematic approach. But because of time pressures—as well as a dearth of perioperative templates, guidelines, and checklists—a cursory history and physical exam often takes the place of a comprehensive evaluation.

A thorough medical history is the most valuable tool of a physician doing a preop consult, but a comprehensive evaluation also involves the assessment of perioperative risk factors, ancillary tests to consider, and interventions to recommend to mitigate risks. Although various published guidelines address specific systems, there are few places where family physicians can find a complete toolkit. The text and tables that follow, which form the core of a comprehensive resource initially compiled to help our residents conduct clear and effective preoperative consults, will help you safeguard your patients.

A system-by-system review starts with the heart

The vast majority of perioperative problems fall into a handful of categories: cardiac, pulmonary, renal, infectious, and hematologic complications (TABLE 1). When a surgeon requests a preoperative evaluation, however, the patient’s cardiac status is generally the primary concern. This is also the portion of the preop consult with the most formally structured guidelines; those issued by the American College of Cardiology and American Heart Association (ACC/AHA) are the most widely used.¹ Initially based primarily on expert opinion, the ACC/AHA guidelines are increasingly evidence-based (http://circ.ahajournals.org/cgi/reprint/CIRCULATIONAHA.109.192690).^1,2 These guidelines address the evaluation of patients for noncardiac surgery. Both cardiac surgery and emergent operations are beyond the scope of the guidelines, and are not addressed here.

Patients with unstable coronary syndromes—eg, unstable angina or myocardial infarction (MI) within the past 30 days, decompensated heart failure (HF), significant arrhythmias, or severe valvular disease—face an increased risk of perioperative morbidity and mortality. To reduce the risk, such patients require optimization of the underlying condition before undergoing elective surgery.¹

Stable ischemic heart disease, compensated HF, diabetes, chronic renal failure/insufficiency (CRF), cerebrovascular disease, and poor functional capacity (defined as <4 metabolic equivalents [METS]) in an asymptomatic patient also increase the risk of complications, but to a lesser degree. If a patient has coronary artery disease, evidence of ischemia on preoperative testing, or more than 1 of these clinical risk factors, surgery may proceed. Keep in mind, though, that the ACC/AHA guidelines suggest that the use of a beta-blocker, titrated to control heart rate and blood pressure, is reasonable in intermediate- or high-risk procedures (TABLE 1).^1,3,4

Is additional cardiac testing necessary? Whether you’re assessing for cardiac status or other risks, for that matter, evidence supports the use of ancillary testing in only a small minority of surgical patients. A general rule of thumb—regardless of the system you’re assessing—is to consider adjunctive testing only if the outcome has the potential to alter patient management. Thus, exercise stress testing or resting electrocardiography (EKG), among other tests, may be considered on an individual basis (TABLE 2), but studies have failed to demonstrate improved outcomes with added testing of cardiac status on a routine basis.^5,6

Evidence is insufficient to make a firm recommendation regarding additional cardiac testing, even for patients with more than 3 clinical risk factors. Nonetheless, the ACC/AHA guidelines favor the use of adjunctive testing in such cases, especially for patients who are candidates for high-risk procedures, such as vascular surgery.¹

What’s the local standard of care? Studies to determine when further testing is beneficial and which tests would benefit which patients are ongoing. In the absence of definitive findings, it behooves primary care physicians to familiarize themselves with the practices and preferences of the cardiologists and anesthesiologists at the facility where the surgery will be performed and to follow the local standard of care.

 

TABLE 1
Identifying—and minimizing—perioperative risk

Patient-specific risk factors	Procedure-specific risk factors	Risk reduction recommendations
Cardiac
Major risks • Decompensated HF • Severe valve disease • Significant arrhythmia • Unstable coronary syndrome Other cardiovascular risks • Cerebrovascular disease • CRF or AKI • Compensated/prior HF • Diabetes • Functional capacity <4 METS • Ischemic heart disease	Vascular surgery	• Optimize treatment of underlying conditions • Consider beta-blockers perioperatively1,3,4 • Consider adjunctive testing if results could alter patient management
Pulmonary
• Acute URI • Requiring assistance with ADLs • Age >60 years • Elevated BUN (>21 mg/dL) • COPD • HF • Hypoalbuminemia (<35 g/L) • Presence of any systemic disease	• Emergency surgery • General anesthesia • Surgery >3 h • Abdominal, head or neck, thoracic, or vascular surgery • Neurosurgery	• Postop incentive spirometry • Postop nasogastric tube • Consider intraoperative use of LMA • Smoking cessation (30 days preoperatively)28
Renal
• Age >60 years • CRF (especially with creatinine >2.1 mg/dL) • Diabetes (especially insulin-dependent) • HF • Jaundice	• Aortic or cardiovascular surgery • Liver transplantation	• Ensure preoperative euvolemia and good osmolar status • Minimize exposure to nephrotoxins • Avoid perioperative hypotension (maintain MAP >65 mm Hg) • Consider preoperative dialysis if GFR <15 mL/min14
Infectious
• Advanced age • Corticosteroid use • Hyperglycemia • Hypoalbuminemia • Immunocompromised • Malnutrition/obesity • Peripheral vascular disease • Postoperative incontinence • Preexisting infection • Prior radiation therapy • Smoking	• Blood transfusion • Surgery >3 h • Perioperative hypothermia • Perioperative hypoxia • Preoperative shaving • Prolonged preoperative hospital stay	• Optimize diabetes management (HbA1c <7); tight perioperative glycemic control • Treat preexisting infections • Provide nutritional supplementation (7-14 days preoperatively) • Smoking cessation (30 days preoperatively)28
Hematologic: Perioperative bleeding
• Collagen vascular disease • GI or urogenital blood loss • Heavy or prolonged menses • Hematologic disease • Hemophilia or other inherited disorder • History of easy bruising or bleeding • Hypersplenism • Liver or renal disease • Severe bleeding after dental extraction, other surgery, or childbirth • Physical findings suggestive of purpura, hematoma, jaundice, or cirrhosis • Use of medications that affect hemostasis	• Minimal risk/JHSRCS 1 (eg, breast biopsy, carpal tunnel procedure, cataract surgery) • Mild risk/JHSRCS 2 (eg, laparoscopy, arthroscopy, inquinal hernia repair) • Moderate risk/JHSRCS 3 (eg, open abdominal procedure, arthroplasty) • Significant risk/JHSRCS 4 (eg, open thoracic surgery, major vascular/skeletal procedure)	• Optimize treatment of preexisting conditions • Discontinue antihemostatic medications, if medically feasible • Consider autologous blood banking
Hematologic: Perioperative anemia
• Hemoglobinopathies • Preexisting iron deficiency anemia • Preexisting pernicious anemia	• Risk of bleeding based on type of surgery (see Perioperative bleeding, above)	• Correct anemia prior to surgery • Consider preoperative erythropoietin • Avoid preoperative transfusion
Hematologic: Venous thromboembolism
• Acute medical illness • Age (older) • Cancer (active or occult); cancer therapy • Estrogen/SERMs • Erythropoiesis-stimulating agents • Immobility • IBD • Lower-extremity paresis • Myeloproliferative disorders • Nephrotic syndrome • Obesity • Paroxysmal nocturnal hemoglobinuria • Pregnancy/postpartum • Previous VTE • Smoking • Thrombophilia • Venous compression	• Cardiothoracic surgery • Central venous catheterization • Major surgery (general, gynecologic, orthopedic, peripheral vascular, or urologic) • Neurosurgery • Trauma	• Ensure early, aggressive mobilization • Provide mechanical prophylaxis • Consider chemoprophylaxis
ADL, activities of daily living; AKI, acute kidney injury; BUN, blood urea nitrogen; COPD, chronic obstructive pulmonary disease; CRF, chronic renal failure/insufficiency; GFR, glomerular filtration rate; GI, gastrointestinal; HbA1c, hemoglobin A1c; HF, heart failure; IBD, inflammatory bowel disease; JHSRCS, Johns Hopkins Surgical Risk Classification System; LMA, laryngeal mask airway; MAP, mean arterial pressure; METS, metabolic equivalents; SERMs, selective estrogen receptor modulators; URI, upper respiratory infection; VTE, venous thromboembolism.

TABLE 2
When should you order these ancillary tests?*

Albumin† For at-risk populations9
BUN, creatinine, electrolytes For at-risk subpopulations21
Chest x-ray It depends. It is not used routinely for predicting risk but may be appropriate for patients with previous diagnosis of COPD or asthma.9
CBC, platelets Do not order routinely; check hemoglobin if procedure increases risk for bleeding.
Coagulation studies Do not order routinely.35,36
Echocardiogram It is reasonable to order for patients with dyspnea of unknown origin, history of HF and worsening dyspnea, or other change in clinical status and may be considered for patients with previously documented cardiomyopathy.1
EKG Vascular surgery: Order for patients with ≥1 clinical risk factors; it is also reasonable for patients with no clinical risk factors.1Intermediate-risk procedure: Order for patients with CHD, PAD, or CVD and consider for patients with ≥1 clinical risk factors.1
Exercise stress-testing Order for patients with active cardiac conditions; it is reasonable for vascular surgery candidates with ≥3 clinical risk factors and poor functional capacity and may be considered for patients undergoing vascular or intermediate-risk procedure who have 1-2 clinical risk factors and poor functional capacity.1
Spirometry, pulmonary-function testing Do not order routinely for predicting risk, but may be appropriate for patients with previous diagnosis of COPD or asthma.9
Urinalysis Order routinely.20
BUN, blood urea nitrogen; CBC, complete blood count; CHD, coronary heart disease; COPD, chronic obstructive pulmonary disease; CVD, cardiovascular disease; EKG, electrocardiography; HF, heart failure; PAD, peripheral artery disease.
*Most commonly recommended ancillary tests for which there are at least minimal data to suggest the validity of the opinion-based recommendation. Answers are opinion-based, not evidence-based. With the exception of albumin testing, the tests listed here are lacking in patient-oriented evidence of benefit from routine use.
† Routine testing of albumin levels is evidence-based.

 

Identify pulmonary risks with help from ACP
Postoperative pulmonary complications are as prevalent as cardiac complications, and contribute equally to morbidity, mortality, and length of stay. But pulmonary complications are better predictors of long-term mortality after surgery.⁷

There are several well-validated risk factors for increased perioperative pulmonary morbidity and mortality—HF, chronic obstructive pulmonary disease (COPD), advanced age, and the need for assistance with activities of daily living among them. In addition to identifying patient-specific risk factors, knowledge of the type of surgery planned will provide insight into procedure-specific risk factors (TABLE 1). The approach to the surgical pulmonary patient is addressed in an American College of Physicians (ACP) guideline published in 2006 and available at http://www.annals.org/content/144/8/575.full.pdf+html.⁷

What tests to consider? The ACP guideline is notable not only for its recommendations, but for the things that are not recommended but may nevertheless be considered the standard of care in some locales. Chest radiography and spirometry are 2 such examples. Although these tests may be appropriate on an individual basis for patients with a previous diagnosis of COPD or asthma, their routine use is of little value—and the ACP does not recommend them as part of a standard preop evaluation.⁷ Some laboratory tests may aid in risk stratification, however.

A serum albumin level <35 g/L is strongly associated with postop pulmonary complications.⁸ Checking levels in all patients suspected of hypoalbuminemia, including any patient with 1 or more pulmonary risk factors, is reasonable for a physician performing a preoperative evaluation. Consider checking blood urea nitrogen (BUN) levels, as well. Uremia (BUN >21 mg/dL) is also associated with increased pulmonary complications, although not as strongly as hypoalbuminemia.

Postpone or proceed? Acute conditions are another key consideration. An upper respiratory infection (URI) increases the risk of postoperative pulmonary complications, especially in children.^9,10 A simple algorithm offers guidance in deciding when to postpone surgery in pediatric patients with a URI:⁹

Recommend that it be delayed if the procedure involves general anesthesia and 1 or more of the following risk factors is present: asthma, a history of prematurity, copious secretions, a parent who smokes, planned use of an endotracheal tube, or a procedure involving the airway.

Surgery can proceed if symptoms of the infection are mild, general anesthesia is not required, or a risk/benefit analysis supports it. Considerations include the urgency of the procedure, whether the surgery has previously been postponed, the comfort level of the clinicians involved, and the distance the family must travel for the procedure.¹¹

If you recommend that surgery proceed as planned, suggest perioperative interventions to mitigate risk. Recommend that a laryngeal mask airway be used, if needed, in place of an endotracheal tube; that pulse oximetry monitoring occur; that good hydration and humidification of air be provided; and that the patient receive anticholinergic agents for secretions.

Other measures that have been shown to be effective in reducing perioperative pulmonary complications include deep breathing exercises (incentive spirometry) and the use of a nasogastric tube for those with postoperative emesis, intolerance of oral intake, or symptomatic abdominal distension.⁷ If your patient has risk factors for pulmonary complications, include a recommendation for a postop nasogastric tube in your preop consultation note. However, newer data indicating that patients had fewer pulmonary complications, a more rapid return of normal bowel function, no increased discomfort, and no increase in anastomotic leaks without a nasogastric tube^12,13 may lead to guideline revision.

A scoring system helps evaluate renal risk
Patients with CRF face increased risk of perioperative morbidity and mortality. But as long as the glomerular filtration rate (GFR) is >25 mL/min—which is only 25% of normal—surgery is generally well tolerated. As GFR drops to 10 to 15 mL/min, the rate of surgical complications rises rapidly, reaching 55% to 60%. For such patients, preoperative dialysis is worth considering.¹⁴

Postoperative acute kidney injury (AKI), as acute renal failure is now known,¹⁵ is associated with a 58% mortality rate.¹⁶ Fortunately, this complication develops in only about 1% of surgical patients.¹⁷ Both patient-specific risk factors (CRF, with creatinine >2.1 mg/dL; HF; diabetes, particularly being insulin dependent; age >60 years; jaundice) and procedure-specific risks (aortic, cardiovascular, or liver transplant surgery) help predict which surgical candidates face the highest risk.^16,18,19 Thakar et al have developed a scoring system to identify those at greatest risk for AKI.²⁰ (See “Cardiovascular surgery and acute kidney injury: Scoring the risk” at www.jfponline.com by clicking on “Before surgery: Have you done enough to mitigate risk?” and scrolling to the end.)

 

Minimize renal complications. Helping patients achieve good intravascular volume and osmolar status preoperatively will reduce their risk of renal complications. Other prophylactic measures: Minimize exposure to nephrotoxins (eg, nonsteroidal anti-inflammatory drugs or contrast media) to the extent possible. Consider evaluating the serum electrolyte and creatinine levels of patients with multiple risk factors to determine whether they can safely undergo surgery; some experts suggest preoperative urinalysis, as well.¹⁸

Patients with end-stage renal disease have very high perioperative morbidity.²¹ They are at increased risk for hyperkalemia, infection, hyper- and hypotension, bleeding, arrhythmias, and clotted fistulas, in descending order of incidence.¹⁸ Preoperative planning, including the need for dialysis before surgery, is necessary to manage these risks.

Risk of postop infection: Focusing on the foreseeable
Postoperative infections, both at the surgical site and remote from the incision, are a significant cause of morbidity and mortality. Pneumonia is among the most prominent remote infections associated with surgery,²² and early ambulation, deep breathing exercises, and tight glycemic control can greatly decrease the risk.

Surgical site infection (SSI) remains an important concern, occurring in 37% of cases.²³ Risk factors include hyperglycemia, malnutrition, perioperative steroid use, preexisting infections, tobacco smoking, peripheral vascular disease, advanced age, radiation therapy, blood transfusions, prolonged preoperative stay, preoperative shaving, hypothermia, hypoxia, length of operation, and postoperative incontinence.²⁴ While many of these risk factors are dependent on interventions in the operating room and recovery room or during subsequent hospitalization, it is important to address foreseeable risks as part of the preoperative evaluation.

Glycemic control is crucial. Perhaps the most well-documented risk for SSI is hyperglycemia—a common problem among hospitalized patients.¹⁶ Hyperglycemia impairs leukocyte and complement function,^25,26 thereby increasing risk of infectious complications. Tight glycemic control in the surgical patient, especially on the surgical intensive care unit, has been associated with improved outcomes.²⁷

Identify the presence of diabetes in the preoperative consult note, and adjust the patient’s medication regimen as needed, to help him or her achieve optimal glycemic control. In some cases, it may be necessary to delay nonurgent surgery until the patient achieves adequate control.

Malnutrition is another risk factor for SSI. For patients who are undernourished or morbidly obese, checking serum albumin levels may be beneficial. Supplementation for 1 to 2 weeks prior to surgery may decrease the risk of infection for patients who are undernourished;²⁸ for obese patients, weight loss is beneficial. Although significant preoperative weight loss may not be possible, it is important to list an elevated body mass index as a risk factor in the consultation note.

Corticosteroids, used to treat conditions such as COPD, inflammatory bowel disease, allergies, and autoimmune disorders, are another risk factor for perioperative infection. In addition to their effect on glycemic control, corticosteroids directly suppress the immune system. Whenever possible, they should be discontinued preoperatively. If this is not possible, call attention to the patient’s use of corticosteroids in the consultation note.

Preexisting infection presents the possibility of the spread of organisms to the surgical site and, whenever possible, surgery should be postponed until the infection resolves. If the patient has a history of prior infection or colonization with methicillin-resistant Staphylococcus aureus, be sure to include that in the consultation note, as well.

Leukocyte-containing blood product transfusions are associated with a 2-fold increase in some postop infectious complications.^29-31 This is in addition to the well-known risk of bloodborne pathogens associated with transfusions, and is yet another reason to avoid perioperative transfusions whenever possible.

 

Smoking impairs tissue oxygenation, which delays healing and increases risk of infection. Smoking cessation should be strongly encouraged at every preoperative consultation. Recommend nicotine replacement therapy even for patients who aren’t willing to quit altogether; point out that giving up cigarettes for just 30 days (or more) before surgery can decrease the likelihood of complications.²⁸

In addition to these identified risk factors, anything that compromises the immune status increases the risk of infection. Alcohol or drug abusers, chronic pain patients, transplant recipients, cancer patients taking immunosuppressants, postsplenectomy patients, and patients with HIV are all at increased risk. Identify any such conditions during your preoperative evaluation, and be sure to include them in your communication with the surgical team.

A common request in preop consults relates to bacterial endocarditis prophylaxis. Only an extremely small number of cases of infective endocarditis occur with dental procedures, however, so the benefits of antibiotic prophylaxis would be minimal, even if the prophylactic therapy were 100% effective.³² As a result, the ACC/AHA guidelines recommend prophylaxis for dental procedures only for patients with underlying cardiac conditions associated with the highest risk of adverse outcome from infective endocarditis. Administration of antibiotics solely to prevent endocarditis is not recommended for patients undergoing genitourinary or gastrointestinal tract procedures.³²

Hematologic evaluation: Address risks of bleeding, clotting
Historically, a variety of tests have been employed in an effort to identify patients at risk for bleeding complications prior to surgery—including prothrombin time, partial thromboplastin time, platelet count, and bleeding time, or platelet function. While highly reproducible, automated, and inexpensive when considered individually, the cumulative cost of routine use of these tests is high.³³

A recent review of the literature indicates that, for surgical patients without synthetic liver dysfunction or a history of oral anticoagulant use, routine testing is of little value in the assessment of bleeding risk.³⁴ Patients with a negative bleeding history do not require routine coagulation screening prior to surgery.³⁵

Instead, use the medical history to identify risk factors for bleeding. These include excessive bruising, nosebleeds, prolonged bleeding after cuts, bleeding >3 minutes after brushing teeth, and heavy or prolonged menses (TABLE 1). Patients with a past medical history of liver disease; renal failure; hypersplenism; hematologic disease; collagen vascular disease; hemophilia or other inherited hemorrhagic disorder; gastrointestinal or urogenital blood loss; and severe bleeding after dental extraction, other surgery, or childbirth are also at heightened risk, as are those who take medications that affect hemostasis. Physical findings suggestive of risk include purpura, hematoma, jaundice, and signs of cirrhosis.³⁴

While laboratory testing is only appropriate to confirm those at risk in the subpopulation selected by the history and physical, here, as with other adjunctive testing, it is important to consider local standards and the preferences of the surgeon who requested the preop consult.

Treat anemia. Preoperative anemia is linked to adverse outcomes in surgical patients,³⁶ although it is not clear whether the anemia itself or the perioperative transfusions associated with the condition are at the root of the problem.³⁷ Macrocytic anemia may require treatment with vitamin B₁₂ and folate; iron deficiency anemia is treated with iron. Some physicians also recommend the use of erythropoietin starting 3 weeks prior to surgery for patients with normocytic anemia with hemoglobin <13 g/dL.^38,39

Thromboembolism risk. Excessive clotting is responsible for more perioperative complications than excessive bleeding. There is a high prevalence of venous thromboembolism (VTE) among surgical patients, with both patient- and procedure-specific risk factors. Although a variety of coagulopathies increase the baseline risk for VTE, routine laboratory screening of the general surgical population for thrombophilia is not recommended.^34,35

When risk factors are present based on both the patient’s medical history and the type of procedure, prophylactic measures may be needed (TABLE 3). Options include mechanical prophylaxis (graduated compression stockings and intermittent pneumatic devices) and chemoprophylaxis. Recommended for high-risk cases, such as patients undergoing orthopedic surgery that precludes early mobilization, chemoprophylaxis options include low-molecular-weight heparin, low-dose unfractionated heparin, fondaparinux (a synthetic factor Xa inhibitor), and vitamin K antagonists such as warfarin.⁴⁰ Aspirin alone is not recommended, as it has not been found to be an effective prophylaxis for VTE.

CASE After following this system-by-system review of your patient, Charlie H, you identify and explicitly communicate the following risk factors in your consultation note:

• Cardiovascular: type 2 diabetes, low functional capacity
• Pulmonary: advanced age
• Renal: advanced age
• Infectious: type 2 diabetes, advanced age, BMI=39
• Hematologic: advanced age, obesity

Based on these findings, you develop the following plan for Charlie H, detailed in the consultation note you submit to the surgical team:

 

• Continue home diabetes medications perioperatively, supplemented with a basal-bolus insulin regimen.
• Initiate incentive spirometry postoperatively; use an NG tube if postoperative nausea and vomiting occur.
• Maintain MAP >65 mm Hg.
• Institute aggressive early ambulation and use of graduated compression stockings for DVT prophylaxis.
  Submitted by ___________ on ________.

TABLE 3
Perioperative thromboembolism: Risk and prophylaxis

DVT/VTE risk40	Prophylaxis recommendations
Low (<10%) • Mobile patients40 • Minimal patient-specific risk factors • Surgery <30 min41	• Early mobilization
Medium (10%-40%) • Most general, gynecologic, or urologic procedures40 • Surgery >30 min41 • Additional patient-specific risk factors • Moderate-risk procedure with high risk of bleeding35	• Chemoprophylaxis (LMWH, LDUH, Fpx) • Mechanical prophylaxis GCS; may consider adding IPD)
High (40%-80%) • Trauma, major surgery40 • Either patient or procedure is high risk for VTE and patient is at high risk of bleeding	• Chemoprophylaxis (LMWH, Fpx, VKA) • Mechanical prophylaxis (GCS and IPD)
DVT, deep vein thrombosis; Fpx, fondaparinux; GCS, graduated compression stockings; IPD, intermittent pneumatic device; LDUH, low-dose unfractionated heparin; LMWH, low-molecular-weight heparin; VKA, vitamin K antagonists; VTE, venous thromboembolism.

CORRESPONDENCE Mark K. Huntington, MD, PhD, FAAFP, Center for Family Medicine, 1115 East Twentieth Street, Sioux Falls, SD 57105; [email protected]