CHAPTER 39: Preoperative Considerations

Each year, more than 30 million surgical procedures are performed. During these, nearly 1 million patients suffer a postoperative complication (Mangano, 2004). As surgeons, gynecologists assume responsibility for assessing a patient’s clinical status to identify modifiable risk factors and prevent perioperative morbidity. However, clinicians should also be prepared to diagnose and manage such complications if they arise.

A properly performed preoperative evaluation serves three important functions. It uncovers comorbidities that require further evaluation and improvement to avert perioperative complications. Second, evaluation allows effective use of operating room resources (Roizen, 2000). Finally, the surgeon is able to anticipate potential problems and devise an appropriate perioperative plan (Johnson, 2008).

In many cases, a thorough history and physical examination averts the need for medical consultation. However, if a poorly controlled or previously undiagnosed disease is discovered, consultation with an internist can be beneficial. Preoperative internal medicine consultation does not provide “medical clearance” but rather offers a risk assessment of a woman’s current medical state. For consultation, a summary of the surgical illness is provided, and clear questions are posed to the consultant (Fleisher, 2009; Goldman, 1983). In addition, a complete history and physical examination and prior medical records that report already completed diagnostic testing should be available to the consulting physician. This can prevent unnecessary surgical delays and cost from redundant testing.

Risk Factors for Pulmonary Complications

Common postoperative pulmonary morbidities include atelectasis, pneumonia, and exacerbation of chronic lung diseases. Incidences of such complications following surgery are estimated to be between 20 and 70 percent (Bernstein, 2008; Brooks-Brunn, 1997; Qaseem, 2006).

Risks for pulmonary complications fall into one of two major categories: procedure-related and patient-related. Of procedure-related risks, upper abdominal incisions as they approach the diaphragm can worsen pulmonary function through three mechanisms, shown in Figure 39-1. Resulting poor diaphragmatic movement can produce persistent declines in vital capacity and in functional residual capacity. These predispose to atelectasis (Warner, 2000). Surgery duration is another procedure-associated factor. Operations in which patients receive general anesthesia for longer than 3 hours are associated with nearly double the rate of postoperative pulmonary complications. Finally, emergency surgery remains a significant independent risk. Although these factors are largely unmodifiable, an appreciation of their sequelae should prompt increased postoperative vigilance.

Of patient-associated factors, age plays a role. Individuals older than 60 years are at increased risk for developing postoperative pulmonary complications. After patients are stratified for comorbidities, those between 60 and 69 years have a twofold increased risk. In those older than 70 years, risk rises threefold (Qaseem, 2006). Importantly, for at-risk patients, baseline cognition should be documented and postoperative sensorium monitored, as changes may be an early indicator of pulmonary function compromise.

Smoking, specifically a greater than 20-pack-year smoking history, confers a high incidence of postoperative pulmonary complications. Fortunately, this risk can be reduced with smoking abstinence before surgery. Preoperative cessation for at least 6 to 8 weeks offers significant improvement in lung function and reversal of smoking-related immune impairment (Akrawi, 1997; Buist, 1976). Other short-term benefits may be related to reduced nicotine and carboxyhemoglobin levels, improved mucociliary function, decreased upper airway hypersensitivity, and improved wound healing (Møller, 2002; Nakagawa, 2001). Patients with a 6-month or longer history of smoking cessation have complication risks similar to those who have never smoked. Moreover, patients often see surgery as an opportunity for positive change (Shi, 2010). Brief interventions offered in close proximity to surgery may have small benefit on long-term smoking behavior (Thomsen, 2014). Education alone may prompt successful behavior modification. For others, agents to assist with smoking cessation can be found in Table 1-4,.

In chronic obstructive pulmonary disease (COPD), inflammatory mediators may account for the intra- and extrapulmonary complications observed in affected patients (Maddali, 2008). Simple COPD optimization may not reduce the incidence of postoperative pulmonary complications. However, postoperative physiotherapy and incentive spirometry with inspiratory muscle training reduce complication rates (Agostini, 2010).

Obesity can decreases chest wall compliance and functional residual capacity and predispose patients with a body mass index (BMI) ≥30 kg/m² to intra- and postoperative atelectasis (Agostini, 2010; Zerah, 1993). Eichenberger and colleagues (2002) observed that pulmonary changes in these patients may persist for more than 24 hours and require aggressive postoperative lung expansion. Moreover, in obese patients undergoing laparoscopy, these pulmonary parameters are further compromised by increased intraabdominal pressures from pneumoperitoneum, as described in Chapter 41.

Asthma, if well-controlled, is not a risk factor for postoperative pulmonary complications. Warner and coworkers (1996) reported that rates of bronchospasm were less than 2 percent in asthmatic patients.

Diagnostic Evaluation

History and Physical Examination

Elements in a pulmonary review of systems that may serve as harbingers of underlying disease include poor exercise tolerance, chronic cough, and otherwise unexplained dyspnea (Smetana, 1999). Examination findings of decreased breath sounds, dullness to percussion, rales, wheezes, rhonchi, and a prolonged expiratory phase can carry a nearly sixfold increase in pulmonary complications (Straus, 2000).

Pulmonary Function Tests (PFTs) and Chest Radiography

In general, pulmonary function tests (PFTs) offer little information during preoperative pulmonary assessment of patients undergoing nonthoracic procedures. Outside of diagnosing COPD, PFTs are not superior to a thorough history and physical examination (Johnson, 2008; Qaseem, 2006). However, if the etiology of pulmonary symptoms remains unclear after clinical examination, then PFTs may provide information to alter perioperative management.

Chest radiography is not routinely obtained preoperatively. Compared with a clinical history and physical examination, preoperative chest radiographs rarely provide evidence to modify therapy (Archer, 1993). The American College of Radiology (2011) recommends that patients with new or exacerbated cardiopulmonary symptoms or those older than 70 years with chronic cardiopulmonary disease as suitable candidates for imaging. Although not exhaustive, conditions for which radiography may be reasonable include acute or chronic cardiovascular or pulmonary disease, cancer, American Society of Anesthesiologist (ASA) status >3, heavy smoking, immunosuppression, recent chest radiation therapy, and recent emigration from areas with endemic pulmonary disease.

Biochemical Markers

The National Veterans Administration Surgical Quality Improvement Program reported that serum albumin levels less than 3.5 g/dL were significantly associated with increased perioperative pulmonary morbidity and mortality rates (Arozullah, 2000; Lee, 2009). For each 1 mg/dL decline in serum albumin concentration, the odds of mortality are increased by 137 percent and morbidity by 89 percent (Vincent, 2004). Serum albumin’s association with morbidity and mortality may be due to confounding comorbidity, and thus it is a marker of malnutrition and disease (Goldwasser, 1997). Although a serum albumin level is not routinely recommended for gynecologic procedures, the information may be predictive in the elderly or in those with multiple comorbidities. Moreover, serum blood urea nitrogen (BUN) levels greater than 21 mg/dL similarly correlate with increased morbidity and mortality rates, but not to the same degree as serum albumin levels.

Preoperative Pulmonary Guidelines

The ASA Classification was created to help predict perioperative mortality rates. It also serves to assess risks for cardiovascular and pulmonary complications (Wolters, 1996). Table 39-1 summarizes the ASA categories and associated rates of postoperative pulmonary complications (Qaseem, 2006).

Postoperative Prevention

Lung Expansion Modalities

Techniques aimed at reducing anticipated postoperative decreases in lung volume can be simple and include deep breathing exercises, incentive spirometry, and early ambulation. In conscious and cooperative patients, deep breathing effectively improves lung compliance and gas distribution (Chumillas, 1998; Ferris, 1960; Thomas, 1994). With these exercises, a woman is asked to take five sequential deep breaths every hour while awake and hold each for 5 seconds. An incentive spirometer can be added to provide direct visual feedback of her efforts. Last, early ambulation can enhance lung expansion and provide some protection against venous thromboembolism. Meyers and associates (1975) demonstrated an increase in functional residual lung capacity of up to 20 percent by simply maintaining an upright posture. Alternatively, formal respiratory physiotherapy may include chest physical therapy in the form of percussion, clapping, or vibration; intermittent positive-pressure breathing (IPPB); and continuous positive airway pressure (CPAP).

The simple and the more formal prophylactic methods are all effective in preventing postoperative pulmonary morbidity, and no method is superior to another. Thomas and colleagues (1994) performed a metaanalysis to compare incentive spirometry (IS), IPPB, and deep-breathing exercises (DBE). In comparison with no therapy, IS and DBE are superior in preventing postoperative pulmonary complications, and greater than 50-percent reductions were observed. In addition, no significant differences were noted comparing IS to DBE, IS to IPPB, and DBE to IPPB (Thomas, 1994). However, chest physical therapy, IPPB, and CPAP are more expensive and labor intensive (Pasquina, 2006). Accordingly, these methods are typically reserved for patients who are unable to perform simpler effort-dependent therapies.

Nasogastric Decompression

Postoperatively, nasogastric tubes (NGTs) are often placed for gastric decompression. However, nasogastric intubation bypasses normal upper and lower respiratory tract mucosal defenses and exposes patients to risks for nosocomial sinusitis and pneumonia. Routine use of NGT after surgery is associated with increased cases of pneumonia, atelectasis, and aspiration compared with selective use (Cheatham, 1995). Indications for selective use might include symptomatic abdominal distention or postoperative nausea and vomiting from suspected ileus. Accordingly, the choice to implement NGT drainage is balanced against respiratory risks.

Risk Factors for Cardiac Complications

Coronary artery disease (CAD) is a leading cause of death in developed countries and contributes significantly to perioperative cardiac complication rates in patients undergoing procedures (Stepp, 2005; Williams, 2009). Accordingly, much of cardiac risk assessment focuses on CAD and is described on page 828.

For congestive heart failure (CHF), a cardiologist may employ strategies to maximize hemodynamic function, such as preoperative coronary revascularization or perioperative medical therapy. With CHF, diuretics are commonly used. However, perioperatively, restraining their use will usually avoid intraoperative hypovolemia and related hypotension. But, if fluid resuscitation is needed, it ideally is gradual and limited to avoid volume overload.

Arrhythmias are usually symptoms of underlying cardiopulmonary disease or electrolyte abnormalities. Accordingly, preoperative management focuses on correcting the primary process. However, if pacemakers and implantable cardioverter-defibrillators (ICDs) are required for arrhythmia treatment prior to surgery, they are typically placed for the same indications as in nonoperative circumstances (Gregoratos, 2002). For those with pacemakers in place, electrosurgery can create electromagnetic interference even during noncardiac surgical and endoscopic procedures. Although encountered less frequently with newer devices, such interference can lead to pacing failure or complete system malfunction (Cheng, 2008). Thus, current guidelines recommend that all systems be evaluated by an appropriately trained physician before and after any invasive procedure (Fleisher, 2009). In addition, as discussed in Chapter 40, intraoperative efforts strive to minimize the chance for electromagnetic interference from electrosurgery. Practices include selecting bipolar electrosurgery if possible, using short intermittent bursts of electric current at the lowest possible energy levels, maximizing the distance between the current source and cardiac device, and placing the grounding pad in a position to minimize current flow toward the device.

Hypertension is not predictive of perioperative cardiac events and should not postpone surgery (Goldman, 1979; Weksler, 2003). Exceptions for elective procedures might include systolic blood pressures >180 mm Hg and diastolic blood pressures >110 mm Hg. If possible, to lower postoperative cardiac complications related to hypertension, blood pressure is lowered several months prior to an anticipated procedure (Fleisher, 2002). Preoperatively, patients on angiotensin-converting enzyme inhibitors and angiotensin-receptor antagonists have their morning dose held to reduce the risk of immediate post­induction hypotension (Comfere, 2005). In all patients with hypertension, avoiding hypo- or hypertension intraoperatively with careful postoperative monitoring is recommended. Importantly, intravascular volume expansion, pain, and agitation may exacerbate postoperative hypertension.

Valvular heart disease is a less frequently encountered cardiac comorbidity. Of these, aortic stenosis carries the highest independent factor for perioperative complications (Kertai, 2004). For other lesions, the degree of heart failure and associated cardiac arrhythmias are the best indicators of risk. If cardiac sounds are suggestive of valvular disease, echocardiography will assist in defining the abnormality. Importantly, endocarditis prophylaxis for valvular lesions during gastrointestinal (GI) or genitourinary (GU) procedures is no longer recommended by the American Heart Association (Nishimura, 2014). The transient enterococcal bacteremia caused by these procedures has not been irrefutably correlated to infective endocarditis.

Diagnostic Evaluation

History and Physical Examination

As with pulmonary disease, history and physical examination can effectively identify or characterize cardiac disease. One questioning strategy is outlined in Figure 39-2. During physical examination, surgeons observe for dependent edema or jugular venous distention, whereas chest palpation searches for the point of maximum impulse and possible thrills. Auscultation of carotid arteries should exclude bruits, and listening at cardiac points investigates cardiac rate, regularity, and extra heart sounds.

Cardiac Testing

Of preoperative cardiac tests, 12-lead electrocardiogram (ECG) and chest radiograph are commonly considered. According to the American College of Cardiology and the American Heart Association (ACC/AHA), ECG is reasonable for patients with known coronary heart disease, significant arrhythmia, peripheral arterial disease, cerebrovascular disease, or other significant structural heart disease. ECG is not recommended for those undergoing low-risk surgeries. For asymptomatic patients without known coronary heart disease, ECG may be considered, but again is not useful in those undergoing low-risk procedures (Fleisher, 2014). Indications for preoperative chest radiography are limited and discussed on page 826. Other testing is usually ordered by a consulting cardiologist and often directed by guidelines discussed next.

Preoperative Cardiac Guidelines

Preoperative guidelines have been developed by several groups to help predict perioperative cardiac complications and direct perioperative care. The two most prominent are: (1) those jointly developed by the ACC/AHA and (2) the Revised Cardiac Risk Index (RCRI) (Fleisher, 2014; Lee, 1999).

Of the two, ACC/AHA guidelines provide a stepwise strategy to assess three major considerations—clinical predictors, surgery-specific risk, and functional capacity—to ascertain the need for cardiac testing (Fig. 39-3). In general, for gynecologic surgery, cardiac complication risks are greatest with major emergency procedures and operations associated with large intravascular fluid shifts. In contrast, lowest risks are found with planned, brief endoscopic procedures.

The Revised Cardiac Risk Index is an easy assessment of clinical predictors. It has been tested extensively and offers accurate estimates of cardiac risk (Lee, 1999). The major difference between the RCRI and the ACC/AHA guidelines is the incorporation of exercise capacity in the ACC/AHA tool. Creators of the RCRI suggest that cardiac risk may be overestimated by a patient’s noncardiac limitations in exercise function, such as musculoskeletal pain. Thus, these investigators place greater emphasis on cardiac and vascular disease markers.

Prevention Strategies

Perioperative Beta-blockers

Preoperative beta-blocker use to reduce in-hospital mortality rates were advocated as a result of the Dutch Echocardiographic Cardiac Risk Evaluation Applying Stress Echocardiography (DECREASE) family of studies. Unfortunately, fictitious databases and errant methods led to a discounting of these results (Erasmus Medical Centre, 2012). Subsequently, Bouri and colleagues (2014) conducted a metaanalysis of the available secure data from randomized controlled trials assessing the value of perioperative beta-blockade. They found the use of beta-blockers caused a statistically significant increase in all-cause mortality rates by 27 percent. Despite a reduction in nonfatal myocardial infarctions, rates of stroke and hypotension increased significantly. These new findings challenge the current AHA guidelines recommending beta-blockade in targeted high-risk patients and even suggest that they may benefit the least (Poldermans, 2009).

Coronary Revascularization

Diagnostic cardiac catheterization is considered in high-risk cardiac patients if noninvasive stress testing suggests advanced disease. In such cases, revascularization through coronary artery bypass grafting (CABG) or percutaneous coronary interventions offer comparable benefits perioperatively (Hassan, 2001).

Anemia

This has been shown to be an independent risk factor for congestive heart failure (Kannel, 1987). A study by Silverberg and associates (2001) found that correction of even mild anemia (Hgb <12.5 percent) offered significant improvements in cardiac function. Iron therapy is not a substitution for appropriate cardiac disease treatment, but extrapolated data suggest that maintaining a hemoglobin level above 10 percent is important and reduces perioperative morbidity and mortality rates for those with cardiac disease.

The rising incidence of hepatic disease has similarly increased the number of patients with hepatic dysfunction. Perioperative care must address this impairment, as the liver plays a central role in drug metabolism; synthesis of proteins, glucose, and coagulation factors; and excretion of endogenous compounds.

Patients with suspected disease are queried regarding family histories of jaundice or anemia, recent travel history, exposure to alcohol or other hepatotoxins, and medication use (Suman, 2006). Physical findings include jaundice, scleral icterus, spider angiomas, ascites, hepatomegaly, asterixis, and cachexia.

If underlying liver disease is known or suspected, hepatic function is assessed. In addition, prothrombin time (PT), partial thromboplastin time (PTT), serum albumin level, and a serum chemistry panel are valuable adjuncts.

Of liver diseases, acute and chronic hepatitis are commonly encountered. With acute hepatitis, regardless of the cause, high associated perioperative mortality rates have been documented by multiple investigators. For this reason, primary management involves supportive care and delay of elective surgery until the acute process has subsided (Patel, 1999). In those with chronic hepatitis, hepatic dysfunction is variable. Compensated disease carries a low risk of perioperative complications (Sirinek, 1987). However, in patients with cirrhosis, the Child-Pugh score is a useful tool to predict survival after abdominal surgery. Clinical measures include serum total bilirubin and albumin levels, international normalized ratio (INR) values, and severity of associated ascites and encephalopathy. Approximate mortality risks based on Child-Pugh class are class A—10 percent; class B—30 percent; and class C—70 percent (Mansour, 1997).

The kidney is involved with metabolic waste excretion, erythropoietin production, and fluid and electrolyte balance. Accordingly, patients with known renal insufficiency typically have serum electrolytes, renal function, and complete blood count (CBC) evaluated prior to surgery. Chronic anemia due to renal insufficiency will typically require preoperative administration of erythropoietin or perioperative transfusion depending on the procedure planned and degree of anemia. Dialysis patients require intensive pre- and postoperative surveillance for signs of electrolyte abnormalities and fluid overload. Ideally, these patients’ volume status and electrolytes (potassium in particular) are optimized by performing dialysis the day prior to surgery. Additionally, further renal insult is averted by avoiding nephrotoxic agents. Pharmacokinetic consultation may be warranted to adjust other medication dosages as serum levels in these patients may be unpredictable postoperatively.

Anemia

This is frequently encountered in preoperative gynecologic surgery evaluation. In the absence of a clear etiology, evaluation serves to potentially correct reversible causes. Queries focus on signs of symptomatic anemia such as fatigue, dyspnea with exertion, and palpitations. Inquiry also seeks to identify risk factors for underlying cardiovascular disease as anemia is less well tolerated in these individuals. The physical examination incorporates thorough pelvic and rectal examination, stool guaiac screening, and urinalysis.

With chronic anemia, erythrocyte indices derived from a CBC reflect a microcytic, hypochromic anemia and show decreases is mean corpuscular volume (MCV), mean corpuscular hemoglobin (MCH), and mean corpuscular hemoglobin concentration (MCHC). Moreover, in classic iron-deficiency anemia from chronic blood loss, an elevated platelet count and decreased reticulocyte count can be seen. In those for whom the cause of anemia is unclear, those with profound anemia, or those who fail to improve with oral iron therapy, addition testing is prudent. Iron studies, vitamin B_12, and folate levels are often indicated. Iron-deficiency anemia produces low serum ferritin and iron levels, elevated total iron-binding capacity, and normal vitamin B₁₂ and folate levels.

Several pharmacologic options are available for preoperative iron supplementation. For oral intake, ferrous sulfate (Feosol, Slow Fe), ferrous gluconate (Fergon), ferrous fumarate (Ircon, Fero-Sequels), and iron polysaccharide (Ferrex) are available. Importantly, each of the ferrous salts has a different content of elemental iron. In general, therapy to correct iron deficiency ideally provides 150 to 200 mg of elemental iron daily. Thus, common and equivalent oral replacement regimens include ferrous sulfate, 325 mg tablet (contains 65 mg elemental iron), or ferrous fumarate, 200 mg tablet (contains 64 mg elemental iron), three times daily. Okuyama and associates (2005) found that provision of 200 mg of elemental iron 2 weeks preoperatively significantly reduced the need for intraoperative transfusion. Constipation is the primary source of preparation intolerance and can be improved with dietary changes, bulk laxatives, and stool softeners (Table 25-6).

In addition to oral forms, several Food and Drug Administration (FDA)-approved intravenous (IV) iron preparations are currently available. These include ferric gluconate (Ferrlecit), iron sucrose (Venofer), ferumoxytol (Feraheme), ferric carboxymaltose (Injectafer), and low-molecular-weight iron dextran (INFeD) (DeLoughery, 2014). The newer preparations have a much lower risk of anaphylactic reactions and are considered safe (Shander, 2010). The hemoglobin effects can be seen as quickly as 1 week after the first dose. For most women, iron therapy administered orally is effective to correct anemia. However, these IV forms may be most appropriate for women with poor absorption secondary to gastrointestinal disease, those with chronic renal disease, or those with an intolerance or lack of response to oral iron.

In women with acute bleeding, transfusion may be required perioperatively. The decision to transfuse depends in part on a patient’s cardiac status. A full discussion of resuscitation is found in Chapter 40.

Autologous Blood Donation

Fear of infection from allogeneic blood transfusions has led to development of autologous transfusion practices. Two of the most popular options include preoperative autologous donation and salvage autologous transfusions. Both are discussed in detail in Chapter 40 (Vanderlinde, 2002).

Coagulopathies

Coagulopathies are generally grouped into two categories—inherited or acquired. Of acquired forms, a careful review of systems and complete medication list, including herbal preparations, may highlight potential causes. In either form, disorders involving platelets or clotting factors can be identified with a careful history and physical examination. A personal history of easy bruising, unexpected amounts of bleeding with minor injury, or lifelong menorrhagia alert a clinician to the possibility of coagulopathy. Screening for coagulopathies is outlined in Chapter 8, and the specifics of replacement are described in Chapter 40. In general, for those undergoing procedures, a transfusion threshold of ≤50,000/μL is used, and for major surgery, ≤100,000/μL (James, 2011).

Oral Anticoagulation

In patients who take anticoagulants following a venous thromboembolism (VTE), the timing of surgery can often lower the risk of postoperative VTE. After an acute VTE, the recurrence risk without anticoagulation is between 40 and 50 percent. However, the risk of recurrent disease drops significantly after 3 months of warfarin therapy. Moreover, a delay in surgery and continued warfarin therapy for an additional 2 to 3 months (6 months total) drops the recurrence risk to 5 to 10 percent and avoids a need for preoperative heparin (Kearon, 1997; Levine, 1995). Thus, in those with recent VTE, a surgical delay, if feasible, may be advantageous and should be considered. When surgery must proceed, protocols for anticoagulant management are described next.

Preoperative Management

Women with atrial fibrillation, mechanical heart valve, or recent VTE are at increased risk for VTE. As a result, chronic oral warfarin therapy is typically prescribed. For these patients, a surgeon must compromise between the need for anticoagulation and risk of surgical bleeding complications. The American College of Obstetricians and Gynecologists (2014b) has summarized recommendations to address this balance (Table 39-2). In general, anticoagulation is typically halted prior to surgery and started shortly postoperatively. Unfortunately, the effects of warfarin reverse slowly. Thus, patients are often transitioned or “bridged” to heparin, which can be stopped and restarting more readily. Both low-molecular-weight heparin (LMWH) and unfractionated heparin (UFH) are options (Table 39-3). Of LWMH choices, enoxaparin (Lovenox) is commonly selected. During bridging, warfarin is stopped several days before surgery, and heparin is begun (Douketis, 2012; White, 1995). In those with a therapeutic INR (between 2.0 and 3.0), approximately 5 to 6 days are required for this ratio to reach 1.5. Once this is achieved, surgery can safely proceed. During bridging therapy, the last dose of LMWH is administered 24 hours prior to surgery. With UFH, therapy is halted 4 to 6 hours prior to surgery (Douketis, 2012).

Unfortunately, emergency surgery may not allow time for such bridging. In these cases, warfarin is halted, and vitamin K is provided. This vitamin promotes factor synthesis, and in urgent cases, a 5- to 10-mg IV dose is suitable (Holbrook, 2012). To minimize the anaphylactic risk, vitamin K is mixed in a minimum 50 mL of IV fluid and administered over at least 20 minutes. Vitamin K requires 4 to 6 hours to achieve clinical effects. Thus, fresh frozen plasma (FFP) may be added at a dose of 15 mL/kg, and each FFP unit has a volume of 200 to 250 mL. Prothrombin complex concentrate (PCC) is a human-derived product containing factors II, IX, and X. PCC does not require thawing and may be used in place of FFP (Ageno, 2012).

Although warfarin antagonizes all vitamin K-dependent clotting factors, newer direct oral anticoagulants (DOACs) inhibit specific factors. The three currently licensed medications are dabigatran (Pradaxa), which targets factor IIa (thrombin), and rivaroxaban (Xarelto) and apixaban (Eliquis), which target factor Xa. Because of their recent introduction, few studies provide recommendations for their perioperative management (Kozek-Langenecker, 2014). The pharmacologic half-life is 14 hours for dabigatran and 9 hours for rivaroxaban and apixaban (Schaden, 2010). Thus, in women with normal preoperative creatinine clearance, stopping rivaroxaban and apixaban 24 hours prior to surgery and halting dabigatran 48 hours prior to surgery is reasonable. The withdrawal time is doubled if the creatinine clearance is <50 mL/min or the risk of perioperative bleeding is high (Ortel, 2012).

For the DOACs, global coagulation tests such as INR, PT, and activated partial thromboplastin time (aPTT) less reliably reflect coagulant activity. For the factor Xa inhibitors rivaroxaban and apixaban, anti-factor Xa assays can be used to measure their activity. For dabigatran, an aPTT >90 seconds and an INR >2 suggest possible overdosing (Lindahl, 2011). Also for dabigatran, thrombin time testing is more sensitive and normal values exclude significant anticoagulant effect. However, the turnaround time with this specific test can be long.

For emergent surgery, the DOACs have no antidote, and management of life-threatening bleeding remains empirical. Fortunately, anticoagulant effects rapidly dissipate because of the drugs’ short half-lives. Indirect evidence suggests that recombinant factor VIIa (NovoSeven) or a prothrombin complex concentrate may be helpful (Ageno, 2012).

Last, antiplatelet agents such as aspirin and clopidogrel (Plavix) may increase surgical bleeding. These are generally stopped 7 days prior to surgery (American College of Obstetricians and Gynecologists, 2014b).

Postoperative Management

After surgery, heparin, either UFH or LMWH, is restarted 12 to 24 hours after major surgery (see Table 39-3). Oral warfarin therapy is started concurrently as several days are required to regain therapeutic levels (Harrison, 1997; White, 1994). Once the INR ranges between 2 and 3, then heparin is discontinued. DOACs are typically restarted 24 hours following surgery. Antiplatelet agents may be resumed 12 to 24 hours following surgery. In all cases, agents are begun only after surgical hemostasis is confirmed.

Hyperthyroidism and Hypothyroidism

The pathophysiologic stress of surgery can exacerbate endocrine conditions such as thyroid dysfunction, diabetes mellitus, and adrenal insufficiency. Of these, both hyper- and hypothyroidism have anesthetic and metabolic derangements unique to each disease state. Nevertheless, management goals for each aim to achieve a euthyroid state before surgery.

Hyperthyroidism carries the risk of developing thyroid storm perioperatively. Moreover, airway compromise is a risk in those with goiter. Thus, during physical examination, tracheal deviation is sought. In addition to thyroid function tests, an ECG and serum electrolyte levels can help predict signs of preexisting metabolic stress. Patients are encouraged to maintain their usual medications at prescribed dosages until the day of surgery.

Newly diagnosed hypothyroidism generally does not require preoperative therapy other than thyroid hormone replacement. Exceptions include cases of severe disease with signs of cardiac depression, electrolyte irregularities, and hypoglycemia.

Diabetes Mellitus

Long-term complications of diabetes mellitus may include vascular, neurologic, cardiac, and renal dysfunction. Thus, a vigilant preoperative risk assessment for these in affected women is essential. In addition, increased postoperative morbidity rates have been linked with poor preoperative glycemic control. Specifically, glucose levels >200 mg/dL and hemoglobin A_1c levels >7 are both associated with significantly increased rates of postoperative wound infection (Dronge, 2006; Trick, 2000).

At minimum, diabetic patients undergoing major surgical procedures benefit from three diagnostic tests—serum electrolyte levels, urinalysis, and ECG. These screen for metabolic disturbances, undiagnosed nephropathy, and unrecognized cardiac ischemia, respectively.

In general, stress induced by surgery and anesthesia elevates catecholamine levels, relative insulin deficiency, and hyperglycemia (Devereaux, 2005). Although glycemic responses vary with surgery, overt hyperglycemia is avoided to minimize postoperative complications related to dehydration, electrolyte abnormalities, diminished wound healing, and even ketoacidosis in type 1 diabetics (Jacober, 1999). However, fluctuations in oral intake and metabolic needs make optimal glycemic control labor intensive. Moreover, clear evidence for glucose targets are lacking. As a result, most providers aim for glucose readings below 200 mg/dL (Table 39-4) (Finney, 2003; Garber, 2004; Hoogwerf, 2006). Table 39-5 and Figure 39-4 summarize perioperative recommendations set forth by Jacober and coworkers (1999) based on disease severity.

Adrenal Insufficiency

Inadequacy of the hypothalamic-pituitary-adrenal (HPA) axis due to secondary suppression from chronic steroid use can lead to perioperative hypotension. Despite this physiologic understanding, controversy surrounds perioperative corticosteroid supplementation.

Corticosteroid users who undergo minor surgical procedures or who use lower doses are generally assumed not to be at risk for adrenal suppression, and additional corticosteroid therapy is not recommended. The value of perioperative supplementation remains an area of chronic debate (Bromberg, 1991; Marik, 2008). Systematic reviews of the literature regarding perioperative supplemental doses of corticosteroids find no evidence to support additional supratherapeutic “stress doses.” Instead, patients should continue their usual daily dose (Kelly, 2013; Marik, 2008). Close hemodynamic monitoring is performed to look for volume-refractory hypotension, at which time stress-dose corticosteroids are initiated for presumed secondary ­adrenal insufficiency. Of note, Marik and Varon (2008) observed that patients receiving corticosteroids due to primary hypothalamic-pituitary-adrenal axis disease require stress doses in the perioperative period. One regimen is hydrocortisone, 100 mg administered IV every 8 hours and titrated to reduced doses as the patient improves.

In the absence of a clinical indication, a rote panel of preoperative tests does not enhance the safety or quality of care. Roizen and colleagues (2000) noted that nearly half of abnormalities found on routine preoperative testing were ignored by clinicians. Moreover, multiple studies have documented the inefficiency of hematologic tests for obtaining clinically significant diagnoses (Kaplan, 1985; Korvin, 1975). Most importantly, diagnostic testing has not been shown to outperform a clinical history and physical examination (Rucker, 1983). Thus, in the absence of changes in clinical status, diagnostic tests found to be normal 4 to 6 months prior to surgery may be used as “preoperative tests.” In patients managed this way, MacPherson and coworkers (1990) found that fewer than 2 percent had significant changes during the course of 4 months.

Codified guidelines for preoperative testing have not been crafted in the United States. However, in the United Kingdom, the National Institute for Health and Clinical Excellence (NICE) has indications for such testing. Complete documents are available at: http://www.nice.org.uk/guidance/cg3.

Obtaining informed consent is a process and not merely a medical record document (Lavelle-Jones, 1993; Nandi, 2006). This conversation between a clinician and patient enhances a woman’s awareness of her diagnosis and contains a discussion of medical and surgical care alternatives, procedure goals and limitations, and surgical risks. Multimedia decision support tools, such as photographs, pamphlets, and educational videos, can augment the discussion (Coulter, 2007; Stacey, 2014). When informed consent cannot be obtained from the patient, an independent surrogate should be identified to represent the patient’s best interest and wishes (American College of Obstetricians and Gynecologists, 2012). Ultimately, written documentation of the entire process serves as a historical record of a patient’s understanding and agreement within the medical records.

Despite a clinician’s recommendations, an informed patient may decline a particular intervention. A woman’s decision-making autonomy must be respected, and a clinician documents informed refusal in the medical record. Appropriate documentation includes: (1) a patient’s refusal to consent to the recommended intervention, (2) notation that the value of the intervention has been explained to the patient, (3) a patient’s reasons for refusal, and (4) a statement describing the health consequences as described to the patient.

Appropriate antibiotic prophylaxis can significantly reduce hospital-acquired infections following gynecologic surgery. Selection recommendations are summarized in Table 39-6. Decisions regarding the choice, timing, and duration of antibiotic prophylaxis are guided by the intended procedure and the anticipated organisms to be encountered (Chap. 3). Typically, a single dose of antibiotics is given at anesthesia induction. Additional doses are considered in cases with blood loss >1500 mL or with duration longer than 3 hours. For obese individuals, a higher antibiotic dose is suggested (American College of Obstetricians and Gynecologists, 2014a). Recommendations do not support subacute bacterial endocarditis prophylaxis prior to GI or GU surgeries, as noted on page 828.

Mechanical bowel preparation was previously advocated if the risk for colon injury was high. This supposedly prevented bowel anastomosis leaks from passage of hard feces and reduced fecal and bacterial loads to lower wound infection rates (Barker, 1971; Nichols, 1971).

Multiple studies, however, question routine mechanical bowel preparation (Duncan, 2009; Platell, 1997). Güenaga and coworkers (2011) performed a review of trials to determine the effectiveness of such preparation on morbidity and mortality rates in colorectal surgery. They found no evidence to support the perceived benefit from mechanical bowel preparation. Similar results have been found with laparoscopic surgery and pelvic floor procedures (Ballard, 2014; Muzii, 2006). Moreover, bowel preparation does not decrease microbial contamination of the peritoneal cavity and subcutis after elective open colon surgery (Fa-Si-Oen, 2005).

Although its routine use should be limited, mechanical bowel preparation may be elected for certain advanced laparoscopic surgeries or for female pelvic reconstructive procedures involving the posterior vaginal wall and anal sphincter. In these cases, evacuation of rectal stool provides additional operating space and undistorted anatomy. Moreover, following sphincteroplasty, preoperative evacuation typically delays stooling and allows initial healing. Various regimens exist: (1) low-residue or clear liquid diets the day(s) prior to surgery, (2) oral cathartics such as 240 mL of senna extract (Senokot, X-Prep) or 240 mL of magnesium citrate, (3) sodium phosphate enemas (Fleet), (4) oral phosphates (Visicol, Fleet Phospho-soda), or (5) oral polyethylene glycol (PEG) solutions (GoLYTELY, NuLYTELY, HalfLytely).

Prophylaxis against VTE ranks in the top 10 patient safety practices recommended by the Agency for Healthcare Research and Quality (AHRQ) and the National Quality Forum (Kaafarani, 2011). In the United States alone, the annual incidence of deep-vein thrombosis (DVT) and pulmonary thromboembolism are estimated to approach 600,000, with more than 100,000 deaths each year (Beckman, 2010). Ten to 30 percent of those diagnosed with VTE die within 1 month of diagnosis. National recommendations for prophylaxis against VTE follow a risk-based approach. The Caprini score is a tool validated using a large sample of general, vascular, and urologic surgery patients (Table 39-7) (Gould, 2012). Despite not being validated in gynecologic surgery, the patient populations are similar enough that extrapolation is reasonable. Caprini scores of 0–1 points categorize a patient as “very low risk,” 2 points reflect “low risk,” 3–4 points confer “moderate risk,” and ≥5 points places patients at “high risk.” These points are transferable to Table 39-8.

Thrombophilias

Of VTE risk factors, thrombophilias are inherited or acquired deficiencies of inhibitory proteins of the coagulation cascade. These can lead to hypercoagulability and recurrent VTE.

Of these heritable coagulopathies, antithrombin deficiency, although rare, is the most thrombogenic. Thrombin is produced by the enzymatic cleavage of prothrombin (Fig. 39-5). Thrombin converts fibrinogen to an active form that assembles into fibrin for clot formation. Antithrombin, previously known as antithrombin III, binds to and inactivates thrombin and the activated coagulation factors IXa, Xa, XIa, and XIIa. If thrombin is not inactivated, then coagulation is favored.

Protein C and protein S deficiencies are other thrombophilias. When thrombin is bound to thrombomodulin on intact endothelium, its procoagulant activities are neutralized. In this bound state, thrombin also activates protein C, a natural anticoagulant. Protein C and its cofactor, protein S, limit coagulation, in part, by inactivating factors Va and VIIIa.

Activated protein C resistance (Factor V Leiden mutation) is the most prevalent thrombophilia and is caused by a single mutation in the factor V gene. The mutation makes FVa resist to degradation by activated protein C. The unimpeded abnormal factor V protein retains its procoagulant activity and predisposes to thrombosis.

Prothrombin G20210A mutation is a thrombophilia stemming from a prothrombin gene missense mutation that leads to excessive prothrombin accumulation. This may then be converted to thrombin to create a hypercoagulable state.

Guidelines to direct thrombophilia testing are lacking in the United States, and those of other international groups are incongruous (De Stefano, 2013). The UK-based NICE guidelines (2012) recommend screening patients who have an unprovoked VTE but not those with a provoked VTE. They also recommend against screening asymptomatic first-degree relatives of a known thrombophilia patient who experienced a VTE.

Hormone Discontinuation

Of risks, hormone use is one factor that can be modified prior elective surgery. Combined oral contraceptive pills (COCs) induce hypercoagulable changes that are reversed if COCs are stopped at least 6 weeks prior to surgery (Robinson, 1991; Vessey, 1986). To balance the risk of unintended pregnancy in women halting COCs, a suitable alternative is recommended with clear instructions on use. In the decision to halt COCs prior to surgery, the risk of VTE in an individual must be weighed against the risk of unintended pregnancy. In those undergoing major surgery and COC continuation, heparin prophylaxis is considered (American College of Obstetricians and Gynecologists, 2013).

Postmenopausal hormone replacement therapy (HRT) may slightly increase the incidence of postsurgical VTE but not to the same degree as the surgical procedure itself (Ueng, 2010). Thus, women are appropriately counseled on this additional postoperative risk, but the value and duration of HRT cessation to negate this increased risk is unclear.

Prophylaxis Options

Various options for VTE prevention exist. Early ambulation, although encouraged after surgery, is not regarded as a primary strategy for VTE prophylaxis (Michota, 2006). Graded compression stockings (T.E.D. hose) prevent pooling of blood in the calves. If these are used alone and fitted properly, DVT rates are reduced 50 percent. If used in conjunction with other methods of prophylaxis, additional benefit is achieved (Amaragiri, 2000). Intermittent pneumatic compression (IPC) primarily works by improving venous flow. It appears to be effective in moderate- and high-risk patients, if initiated prior to the induction of anesthesia and continued until patients are fully ambulating (Clarke-Pearson, 1993; Gould, 2012). Pharmacologic methods of VTE prophylaxis include low-dose UFH, LMWH, and DOACs. Table 39-8 summarizes appropriate treatment strategies based on risk status.