At its simplest, the process of preparing a patient for an operation can involve a rapid assessment in the clinic or emergency room followed by an expeditious trip to the operating room. However, like most care in the contemporary health care system, the process is more commonly complex and involves a formal series of integrated steps to assure best outcomes. It is incumbent upon the surgery team to create an efficient and cost-effective preoperative system and scheduling protocol that result in optimally prepared patients, rare cancellations of operations, and few disruptions of the operating room schedule. A systemic approach to patient preparation focuses upon risk assessment and reduction, as well as education of the patient and family. This effort begins during the first encounter with the surgeon and continues through the moments before the operation. Ideal preoperative systems assign risk based upon evaluations that are derived from sound published evidence and best practices and driven by standardized algorithms to identify and then modify hazards before operations.
Risk Assessment & Reduction
The essence of preparing a patient for an operation regards considering whether the benefits of the operation justify the risks of doing harm, along with deciding how to minimize or eliminate those hazards. The American Society of Anesthesiologists (ASA) classification system (Table 3–2) stratifies the degree of perioperative risk for patients. While somewhat rudimentary, this system has faithfully served anesthesiologists and surgeons in predicting how well patients might tolerate operations, and the scores have been validated by several recent publications. The Acute Physiology and Chronic Health Evaluation (APACHE II and III) is an example of a severity of illness scoring system that may be applied to intensive care unit patients to predict mortality. The value of such assessments lies in numerically designating the severities of patients’ conditions, permitting comparisons of outcomes.
Table 3–2.American Society of Anesthesiologists (ASA) classification system. ||Download (.pdf) Table 3–2. American Society of Anesthesiologists (ASA) classification system.
|ASA Classification ||Preoperative Health Status ||Example |
|ASA 1 ||Normal healthy patient ||No organic, physiologic, or psychiatric disturbance; excludes the very young and very old; healthy with good exercise tolerance |
|ASA 2 ||Patients with mild systemic disease ||No functional limitations; has a well-controlled disease of one body system; controlled hypertension or diabetes without systemic effects, cigarette smoking without chronic obstructive pulmonary disease (COPD); mild obesity, pregnancy |
|ASA 3 ||Patients with severe systemic disease ||Some functional limitation; has a controlled disease of more than one body system or one major system; no immediate danger of death; controlled congestive heart failure (CHF), stable angina, former heart attack, poorly controlled hypertension, morbid obesity, chronic renal failure; bronchospastic disease with intermittent symptoms |
|ASA 4 ||Patients with severe systemic disease that is a constant threat to life ||Has at least one severe disease that is poorly controlled or at end stage; possible risk of death; unstable angina, symptomatic COPD, symptomatic CHF, hepatorenal failure |
|ASA 5 ||Moribund patients who are not expected to survive without the operation ||Not expected to survive > 24 h without surgery; imminent risk of death; multiorgan failure, sepsis syndrome with hemodynamic instability, hypothermia, poorly controlled coagulopathy |
|ASA 6 ||A declared brain-dead patient whose organs are being removed for donor purposes || |
The University Health Systems Consortium (UHC) analyses derive from inpatient administrative and financial datasets to predict risk-adjusted outcomes for mortality, lengths of stay, and cost of care. The vagaries of medical coding can result in discrepancies, and the UHC system does not monitor patients after hospital discharge. Nevertheless, UHC data can identify deficiencies in practice. Although clinical databases are more costly and challenging to implement than commercially available products such as the UHC program, they provide more robust risk-adjusted outcomes data. Examples of clinical databases include those from the Society of Thoracic Surgeons (STS) and the National Surgical Quality Improvement Program (NSQIP). In NSQIP, dedicated nurses prospectively collect and validate an established panel of defined patient variables, comorbidities, and outcomes, and they pursue surveillance for 30 days after hospital discharge. The NSQIP analysis considers patient factors, effectiveness of care, and random variation, and logistic regression models calculate risk-adjusted 30-day morbidity and mortality. These data are reported as odds ratios for comparison with expected outcomes, allowing for the severity of the patients’ illnesses. Immediate benefits of NSQIP present the ability to identify true risk-adjusted data and local opportunities for improvement. For example, Veterans Administration (VA) surgeons reduced postoperative mortality from 3.2% in 2003 to 1.7% in 2005, while the complication rate declined from 17% to 10% (p < 0.0001). This effort focuses upon systems of care, providing reliable data to assess and reduce risks associated with operations. When compared to UHC, NSQIP is much more likely to identify complications because of its surveillance of patients 30 days beyond their hospitalizations.
The NSQIP program has also generated a tremendous repository of data to develop “risk calculators” for a variety of operations and conditions, allowing preoperative risk assessments and hopefully facilitating significant reductions of preoperative hazards. Finally, NSQIP participants have fostered a culture of sharing best practices and processes, both within the published literature and through formal and personal collaborations.
Beyond the obvious physical and emotional implications of adverse outcomes for patients and their families, the financial costs of postoperative complications to the health care system are staggering. It has been postulated that a major postoperative complication adds over $11,000 to the cost of the hospital care of an affected individual and significantly extends the duration of the inpatient confinement. In fact, the total cost of care increases by more than half when a complication develops. Notably, respiratory complications may increase the cost of care by more than $52,000 per patient. Strikingly, data from NSQIP have demonstrated that the occurrence of a serious complication (excluding superficial wound infections) after major operations is an independent risk factor for decreased long-term survival. Therefore, it is crucial that efforts focus upon reducing and eliminating postoperative complications.
Well-designed, systematic preoperative assessment programs can prospectively identify predictors of various complications and drive the ability to attenuate risks and improve outcomes. The perspective of teams of surgeons, physicians, nurses, and others with expertise managing standardized, algorithm-driven preoperative evaluations, often with checklists, is a departure from traditional care that primarily involved solitary surgeons with disparate practices. The new paradigm recognizes that variability in practice is the enemy of efficiency.
The financial dividends appreciated from enhanced results and diminished death and complication rates more than compensate for the expenditures associated with quality improvement efforts and participation in auditing programs such as NSQIP. It is essential that surgeons monitor their patients’ outcomes, preferably in a risk-adjusted fashion, to understand their practices and to demonstrate opportunities for improvement.
In 1977, Goldman published a multifactorial index for assessing cardiac hazards among patients undergoing noncardiac operations. The same group issued a Revised Cardiac Risk Index (RCRI) in 1999, reporting six independent predictors of cardiac complications. These include a history of ischemic heart disease, congestive heart failure, cerebrovascular disease, a high-risk operation, preoperative treatment with insulin, and a preoperative serum creatinine greater than 2.0 mg/dL. The likelihood of major cardiac complications increases incrementally with the number of factors present. Contemporary NSQIP data have led to the development of a risk calculator to predict postoperative cardiac complications. A multivariate logistic regression analysis demonstrated five prognostic factors for perioperative myocardial infarction (MI) or cardiac arrest: the type of operation, dependent functional status, abnormal creatinine, ASA class, and increasing age. The analysis has been validated and has led to the composition of an interactive risk calculator. Another multivariate model demonstrated criteria that predict adverse cardiac events among patients who have had elective vascular operations, and it also suggests improved predictive accuracy among these patients compared to the RCRI. Independent hazards include increasing age, smoking, insulin-dependent diabetes, coronary artery disease, congestive heart failure (CHF), abnormal cardiac stress test, long-term beta-blocker therapy, chronic obstructive pulmonary disease, and creatinine ≥1.8 mg/dL. Conversely, the analysis demonstrated a beneficial effect of prior cardiac revascularization. There is obviously overlap among the factors identified in these models.
The determination of an increased chance of a patient developing postoperative cardiac complications will certainly influence the tenor of preoperative discussions with patients and their family members, especially if the surgeon can present validated data regarding the actual likelihood of a cardiac complication or death. In addition, correctable hazards may be addressed, including smoking cessation, optimal control of diabetes, hypertension, and fluid status, and assurance of compliance with medical measures. Finally, formal risk assessments guide cardiologists with respect to cardiac stress testing, echocardiography, and coronary catheterization among higher-risk patients. Selected patients may be candidates for preoperative revascularization, either with coronary artery stent placement or surgical bypass.
The American College of Cardiology (ACC) Foundation and the American Heart Association (AHA) periodically issue joint recommendations about the cardiac evaluation and preparation of patients in advance of noncardiac operations. These guidelines are evidence based, include an explanation of the quality of the data, and provide comprehensive algorithms for the propriety of testing, medications, and revascularization to assure cardiac fitness for operations. As important as preoperative cardiac risk stratification is, a cardiology consultation also lays the groundwork for postoperative risk assessment and later modifications of coronary risk factors.
Noninvasive and invasive preoperative testing should be performed only when the results will influence patient care. Noninvasive stress testing before noncardiac operations is indicated in patients with active cardiac conditions (eg, unstable angina, recent MI, significant arrhythmias, or severe valvular disease), or in patients who require vascular operations and have clinical risk factors and poor functional capacity. Good data support coronary revascularization before noncardiac operations in patients who have significant left main coronary artery stenosis, stable angina with three-vessel coronary disease, stable angina with two-vessel disease and significant proximal left anterior descending coronary artery stenosis with either an ejection fraction < 50% or ischemia on noninvasive testing, high-risk unstable angina or non–ST-segment elevation MI, or acute ST-elevation MI. However, current data do not support routine preoperative percutaneous revascularization among patients with asymptomatic coronary ischemia or stable angina.
The role of beta-blockers for cardiac protection is evolving, and these agents are no longer empirically advised for all high-risk patients due to potential adverse consequences. Beta-blockers should be continued perioperatively among those patients who are already taking them and among those having vascular operations and at high cardiac risk, including known coronary heart disease or the presence of ischemia on preoperative testing. The role of beta-blockers is uncertain for patients with just a single clinical risk factor for coronary artery disease. Cardiac complication risk calculators may become beneficial in the stratification of patients who should receive beta-blockers to reduce perioperative cardiac complications.
Preoperative aspirin usage should continue among patients at moderate to high risk for coronary artery disease, unless the risk of resultant hemorrhage definitely outweighs the likelihood of an atherothrombotic event. Thienopyridines, such as ticlopidine or clopidogrel, are administered in concert with aspirin as dual antiplatelet therapy following placement of coronary artery stents. They are intended to inhibit platelet aggregation and resultant stent thrombosis, although they certainly increase the risk of hemorrhage. Therefore, if an operation can be anticipated, the surgeon and cardiologist must coordinate efforts regarding the sequence of the proposed operation and coronary stenting, weighing the hazards of operative bleeding while on antiplatelet therapy for a stent versus potential postoperative coronary ischemia. Elective operations with a significant risk of bleeding should be delayed 12 months before the discontinuation of the thienopyridine in the presence of a drug-eluting stent, at least 4-6 weeks for bare-metal stents, and 4 weeks after balloon angioplasty. Therefore, if a patient requires percutaneous coronary artery intervention prior to noncardiac surgery, bare-metal stents or balloon angioplasty should be employed rather than drug-eluting stents. Even when thienopyridines are withheld, aspirin should be continued, and the thienopyridine is to be resumed as soon as possible after the operation. In circumstances such as cardiovascular surgery, the dual antiplatelet agents are continued throughout the perioperative course to minimize the likelihood of vascular thrombosis.
Postoperative pulmonary complications (PPC), such as the development of pneumonia and ventilator dependency, are debilitating and costly. They are associated with prolonged lengths of hospital stay, an increased likelihood of readmission, and increased 30-day mortality. Therefore, it is critical to identify patients at greatest risk for PPC. Established risk factors for PPC include advanced age, elevated ASA class, congestive heart failure, functional dependence, known chronic obstructive pulmonary disease, and perhaps malnutrition, alcohol abuse, and altered mental status. In addition, hazards are greater for certain operations (eg, aortic aneurysm repair, thoracic or abdominal, neurosurgery, head and neck, and vascular), prolonged or emergency operations, and those done under general anesthesia. A risk calculator was devised to predict the likelihood of PPC occurrence, indicating seven independent risk factors. These include low preoperative arterial oxygen saturation, recent acute respiratory infection, age, preoperative anemia, upper abdominal or thoracic operations, duration of operation over 2 hours, and emergency surgery.
A multivariable logistic regression has affirmed that active smoking is significantly associated with postoperative pneumonia, SSI, and death, when compared to nonsmokers or those who have quit smoking. Moreover, this is a dose-dependent phenomenon, predicated upon the volume and duration of tobacco consumption. The benefits of preoperative smoking cessation seem to be conferred after an interval of at least 4 weeks. Conversely, the risk of developing PPC is the same for current smokers versus those who quit smoking for less than 4 weeks before an operation. Smoking cessation also confers favorable effects on wound healing. Therefore, patients should be encouraged to stop smoking at least 1 month before operations, ideally with programmatic support through formal counseling programs and possibly smoking cessation aids such as varenicline or transdermal nicotine.
A recent analysis of patients having general surgery and orthopedic operations demonstrated that sleep apnea is an independent risk factor for the development of PPC. A simple “STOP BANG” questionnaire can screen patients for sleep apnea. The acronym queries Snoring, Tired during day, Obstructed breathing pattern during sleep, high blood Pressure, BMI, Age over 50 years, Neck circumference, and male Gender. Patients with sleep apnea may be managed with continuous positive pressure (CPAP) or bilevel positive airway pressure (BiPAP) devices, both before and after operations. The presence of sleep apnea may also influence anesthesia techniques.
Patients identified as being at highest risk for the development of PPC may benefit from preoperative consultations with respiratory therapy and pulmonary medicine experts. Pulmonary function tests and baseline arterial blood gas tests guide the care of select patients, especially those anticipating lung resections. In addition to smoking cessation, asthma should be medically controlled. Patient education focuses upon inspiratory muscle training (including the usage of incentive spirometry), the concepts of postoperative mobilization, deep inspiration, and coughing, along with oral hygiene (tooth brushing and mouth washes). Respiratory therapists can provide expertise with CPAP and BiPAP systems for patients with sleep apnea. Surgeons and anesthesiologists should collaborate regarding plans for neuromuscular blocking agents and strategies to reduce pain, including the administration of epidural analgesics and the consideration of minimally invasive techniques to avoid large abdominal or thoracic incisions. Finally, formal intensive care unit protocols can promote liberation from ventilator support.
Venous thromboembolism (VTE) events such as DVT or PE are major complications that can lead to death or serious long-term morbidity, including chronic pulmonary hypertension and postthrombotic limb sequelae. Scoring systems stratify patients by their probability of developing a postoperative VTE to guide preventative measures. In the 2012 American College of Chest Physicians (ACCP) recommendations, the patient’s score selects the alternatives of early ambulation alone (very low risk), mechanical prophylaxis with intermittent pneumatic compression (IPC) devices (low risk), options of low-molecular-weight heparin (LMWH) or low-dose unfractionated heparin or IPC (moderate risk), and IPC in addition to either LMWH or low-dose heparin (high risk). Furthermore, an extended course (4 weeks) of LMWH may be indicated among patients undergoing resections of abdominal or pelvic malignancies. Of course, the surgeon must entertain the hazards of pharmacologic prophylaxis when bleeding poses even greater harm than VTE, in which case IPC alone may suffice. Heparin prophylaxis is associated with a 4%-5% chance of wound hematomas, 2%-3% incidence of mucosal bleeding and the need to stop the anticoagulation, and a 1%-2% risk of reoperation. The ACCP 2012 guidelines do not advocate routine vein surveillance with ultrasonography or the insertion of inferior vena cava filters for primary VTE prevention. Notably, antiembolism graduated compression stockings (GCS) do not promote venous blood flow from the leg and can violate skin integrity and result in the accumulation of edema. The efficacy of stocking for VTE prevention is unproven.
Caprini has developed a more elaborate risk calculation that has been validated in a variety of clinical settings and specialties, and is adaptable to standardized order sets (Figure 3–1). This scoring system acknowledges the gravity of individual hazards, including personal and family histories of VTE, the diagnosis of a malignancy, a history of obstetrical complications or known procoagulants, and prolonged operations, among several other factors. It also identifies patients who may either entirely avoid anticoagulation or benefit from an extended duration of LMWH. There is no doubt that the cumulative incidence of VTE extends many weeks after operations, particularly for malignancies and in an era when the duration of hospital stays (and inpatient prophylaxis) has declined. In fact, about one-third to half of patients who manifest a postoperative VTE after cancer surgery do so following hospital discharge. Therefore, regimens of pharmacologic prophylaxis should be maintained after the discharge of patients who have elevated risk scores. The ACCP and Caprini systems are two among several VTE risk assessment tools, each of which has advantages and disadvantages. The system adopted in any hospital or surgery center will be a function of local resources and culture, but it is ideal that surgeons develop and maintain a local standard to minimize the threat of postoperative VTE.
Sample order set page with “Caprini” calculation of venous thromboembolism risk. The total value of checked-off factors indicates the proper preoperative and postoperative prophylaxis regimens, including upon discharge from hospital. (© Boston Medical Center Corporation 2012.)
Patients with diabetes mellitus are more likely to undergo operations than are those without diabetes, and their care is associated with longer lengths of hospital stay, increased rates of postoperative death and complications, and relatively greater utilization of health care resources. It has been established that elevated postoperative blood glucose levels in diabetic patients translate to progressively greater chances of SSIs following cardiac operations, as well as a greater likelihood of postoperative infections and prolonged hospital stays in patients with noncardiac operations. In fact, increased perioperative glucose levels have correlated with a higher risk of SSIs in general surgery, cardiac surgery, colorectal surgery, vascular surgery, breast surgery, hepatobiliary and pancreas surgery, orthopedic surgery, and trauma surgery. The relative risk of an SSI seems to incrementally increase in a linear pattern with the degree of hyperglycemia, with levels greater than 140 mg/dL being the sole predictor of SSI upon multivariate analysis. In one study, the likelihood of an adverse postoperative outcome increased by 30% for every 20 mg/dL increase in the mean intraoperative glucose level. Interestingly, about one-third of patients with perioperative hyperglycemia are not diabetics. Furthermore, the risk of death relative to perioperative hyperglycemia among patients undergoing noncardiac operations has been shown to be greater for those without a history of diabetes than for those with known diabetes. Nevertheless, these data pertain to intraoperative and postoperative blood sugars, not preoperative values.
Current recommendations for desirable glucose ranges in critically ill patients are commonly about 120-180 mg/dL, but the best range for perioperative glucose levels is not yet established, and low levels may result in harm when clinicians try to achieve “tight” control of blood sugars. In fact, trials and meta-analyses have failed to prove a clinical benefit of maintaining glucose levels in the normal laboratory reference range (80-110 mg/dL). Although preoperative blood sugar and hemoglobin A1C levels have not clearly correlated with adverse outcomes, good control of glucose before operations likely facilitates blood sugar management during and after operations. An abundance of data support postoperative glucose control as a major determinant of postoperative complications, with emerging data also indicating an adverse effect of intraoperative hyperglycemia. Interestingly, surgeons may actually be more influential than are patients’ primary care physicians in terms of encouraging preoperative compliance with diabetes medications, at least in the short term. Patients are commonly motivated to attend to medical conditions such as diabetes to enhance chances of postoperative success.
Patients having operations that require fasting status are advised about oral antihyperglycemic medications on the day of surgery in accordance to Table 3–3. Injectable medications such as exenatide and pramlintide are not administered on the day of surgery, and insulin therapy is determined by the duration of action of the particular preparation, as outlined in Table 3–4. Patients with type 1 diabetes require basal insulin at all times. Patients with insulin pumps may continue their usual basal rates.
Table 3–3.Instructions for preoperative management of oral antihyperglycemic medications. ||Download (.pdf) Table 3–3. Instructions for preoperative management of oral antihyperglycemic medications.
|Medication ||Prior to Procedure ||After Procedure |
|Short-acting sulfonylureas: Glipizide (Glucotrol), glyburide (DiaBeta, Glynase, Micronase) ||Do not take the morning of procedure ||Resume when eating |
|Long-acting sulfonylureas: ƒ Glimepiride (Amaryl), glipizide XL (Glucotrol XL) ||Do not take the evening prior to or the morning of procedure ||Resume when eating |
|Biguanides: ƒ Metformin (Glucophage), metformin ER (Glucophage XL) ||Do not take the morning of procedure; do not take the day prior to procedure if receiving contrast dye ||Resume when eating. After contrast dye wait 48 h and repeat creatinine prior to restarting |
|Thiazolidinediones: ƒ Pioglitazone (Actos), rosiglitazone (Avandia) ||Do not take the morning of procedure ||Resume when eating |
|Alpha-glucosidase inhibitors: Acarbose (Precose), miglitol (Glyset) ||Do not take the morning of procedure ||Resume when eating |
|DPP-4 Inhibitors: ƒ Sitagliptin (Januvia) ||Do not take the morning of procedure ||Resume when eating |
|Meglitinides: ƒ Nateglinide (Starlix), repaglinide (Prandin) ||Do not take the morning of procedure ||Resume when eating |
Table 3–4.Instructions for preoperative management of injectable antihyperglycemic medications and insulin. ||Download (.pdf) Table 3–4. Instructions for preoperative management of injectable antihyperglycemic medications and insulin.
|Medication ||Prior to Procedure ||After Procedure |
|Injectable Medications |
|Exenatide (Byetta) ||Do not take the morning of procedure ||Resume when eating |
|Symlin (Pramlintide) ||Do not take the morning of procedure ||Resume when eating |
|Glargine (Lantus) ||Take usual dose the night before or the morning of procedure ||Resume usual schedule after procedure |
|Detemir (Levemir) ||Take usual dose the night before or the morning of procedure ||Resume usual schedule after procedure |
|NPH (Humulin N, Novolin N) ||Take ½ of usual dose the morning of procedure ||Resume usual schedule when eating, ½ dose while NPO |
|Humalog mix 70/30, 75/25, Humulin 70/30, 50/50 Novolin 70/30 (all mixed insulins) ||Do not take the morning of procedure ||Resume usual schedule when eating |
|Regular insulin (Humulin R, Novolin R) ||Do not take the morning of procedure ||Resume when eating |
|Lispro (Humalog), Aspart (Novolog), Glulisine (Apidra) ||Do not take the morning of procedure ||Resume when eating |
|Subcutaneous insulin infusion pumps ||Requires tailored recommendations. In general, most patients may continue their usual basal rate and correction doses, and resume meal-time boluses when eating again |
Multidisciplinary teams, including endocrinologists, surgeons, anesthesiologists, nurses, pharmacists, information technology experts, and others, have developed formal protocols and algorithms for perioperative glycemic control, and an example of a preoperative order set is illustrated in Table 3–5. A typical protocol is nurse-driven and involves checking glucose levels on all diabetic patients in the holding area shortly before an operation. As an example of one protocol, glucose values ≤180 mg/dL are satisfactory and require no treatment. Glucose levels of 181-300 mg/dL prompt the nurse to begin an infusion of intravenous (IV) insulin before the operation, along with a 5% dextrose solution to minimize the chances of hypoglycemia. Endocrinologists are automatically consulted to assist with postoperative insulin management in these patients and in those with insulin pumps. In general, insulin pump therapy is continued along with the infusion of a dextrose solution. Patients with pumps may also require the addition of IV insulin, as per the protocol.
Table 3–5.Example of adult perioperative glycemic control protocol. ||Download (.pdf) Table 3–5. Example of adult perioperative glycemic control protocol.
Patients with glucose levels > 300 mg/dL are assessed for ketones or for acidosis prior to starting an insulin infusion. Markedly elevated preoperative blood sugars warrant special deliberation by all involved. Matters to be considered include the urgency of the operation, whether the underlying condition itself may be contributing to hyperglycemia, metabolic consequences such as the presence of ketoacidosis, the risks of proceeding with an operation at that moment, the likelihood of establishing better control at a later date, and the dangers imposed by postponing the operation. Dramatic elevations (eg, > 300 mg/dL) are typically indicative of chronic poor glucose control, but the clinician often does not have the luxury of perfectly managing diabetes before operations.
Intravenous insulin is best for perioperative glucose control due to its rapid onset of action, short half-life, and immediate availability (as opposed to subcutaneous absorption). Insulin may be administered with an IV bolus technique or via continuous IV infusion, but regular glucose monitoring (eg, hourly for continuous insulin infusions) is necessary in either system to assure adequate control and to avoid hypoglycemia. The insulin administration method before, during, and after an operation (infusion vs bolus) is a function of local resources (eg, glucose meters, blood sample processing, and staffing), as well as the patient’s individual circumstances. After the operation, a patient should be assessed for an insulin infusion regimen if being transferred to a critical care setting, a basal-bolus insulin program, or the resumption of the patient’s usual diabetes medications.
Surgical site infections (SSIs) are major contributors to postoperative morbidity and can be monitored and reduced by multiple complex interventions that are institution-specific. Excellent surgical technique is obviously a major factor in eliminating SSIs, and this involves limiting wound contamination, blood loss, the duration of the operation, and local tissue trauma and ischemia (eg, using sharp dissection rather than excessive electrocoagulation). However, a variety of adjuvant preoperative measures, beyond glycemic control described above, also contribute to the prevention of SSIs. Antibiotics should be administered within the 1-hour period before incision for certain clean operations and for all clean-contaminated, contaminated, and dirty operations. In addition, further dosages of the antibiotics should be infused about every two half-lives during the operation (eg, every 4 hours for cefazolin). Correct antibiotic selection is determined by several factors, such as the bacterial flora that are most likely to cause an infection, local bacterial sensitivities, medication allergies, the presence of MRSA, and the patient’s overall health and ability to tolerate an infection. In clean operations with low rates of infections, the surgeon should contrast the cost and hazards of antibiotics with the likelihood, cost, and morbidity of a postoperative infection. Antibiotic choices for prophylaxis against SSIs are cited in Table 3–6 for a variety of operations. Operations that involve bacteroides should prompt the addition of metronidazole to the regimen, and operations with a dirty wound classification may be guided by culture results and hospital-specific bacteria sensitivities. When antibiotics are administered for SSI prophylaxis rather than for treatment of an established or suspected infection, they are typically not continued after surgery, except in special circumstances such as vascular grafts, cardiac surgery, or joint replacements. Even then, prophylaxis should expire within one to two days. Order sets, automated reminders, and team vigilance are essential to assure the consistent usage of the correct antibiotics at the right time and for the proper duration.
Table 3–6.Examples of prophylactic antibiotic selections for various operations.a ||Download (.pdf) Table 3–6. Examples of prophylactic antibiotic selections for various operations.a
Wound perfusion and oxygenation are also essential to minimize the likelihood of SSIs. A sufficient intravascular blood volume provides end-organ perfusion and oxygen delivery to the surgical site. The maintenance of perioperative normothermia also has salutary effects on wound oxygen tension levels and can consequently reduce the incidence of SSIs. Therefore, the application of warming blankets immediately prior to the operation may support the patient’s temperature in the operating room, especially for high-risk operations such as bowel resections that often involved a prolonged interval of positioning and preparation when a broad surface area is exposed to room air. Similarly, some data support hyperoxygenation with Fio2 ≥80% during the first 2 hours after a major colorectal operation.
Several other adjuvant measures are employed at the surgical site to reduce the incidence of SSIs. Protocols with mupirocin nasal ointment application and chlorhexidine soap showers have reduced the incidence of SSIs among patients colonized with methicillin-sensitive S aureus. During an operation, wound protectors may be deployed to minimize the chances of a superficial or deep SSI developing. Some surgeons (and their teams) change gloves and gowns, and may use a separate set of instruments (that have not come into contact with potential contaminants) for wound closure.
Likely out of concerns about incurring renal insult, surgeons and anesthesiologists have traditionally advocated liberal perioperative fluid resuscitation during recent decades, often overestimating insensible and “third space” fluid losses. As a result, patients can develop significant volume overload that is associated with serious complications. Recent data instead support goal-directed (or protocol-based) fluid restriction as likely resulting in a decreased incidence of cardiac and renal events, pneumonia, pulmonary edema, ileus, wound infections, and anastomosis and wound healing problems, as well as shorter durations of hospital stay. Unfortunately, traditional vital signs, including even central venous pressure, do not reliably correlate with intravascular volume or cardiac output. Moreover, pulmonary artery catheterization has actually been associated with increased mortality, and its implementation for the optimization of hemodynamic status is rarely required. Pulmonary artery catheterization is valuable for few, highly selected patients who exhibit clinical cardiac instability along with multiple comorbid conditions. Newer, minimally invasive modalities for monitoring cardiac output offer promise to determine optimal preload volume and tissue oxygen delivery before and during operations, including esophageal Doppler and analyses of stroke volume variation and pulse pressure variation. The precise standards of goal-directed volume resuscitation remain elusive, but surgeons and anesthesiologists should prospectively collaborate regarding plans for both volume resuscitation and the selection of the type of anesthesia. This is especially so during the management of challenging problems such as pheochromocytomas, when patients require preoperative vasodilatation and then intravascular volume expansion. Another clinical dilemma involves patients with end-stage renal failure. Dialysis should be performed within about 24-36 hours before an operation to avoid electrolyte disturbances, but the surgeon should confer with the nephrologist to minimize intravascular blood volume depletion.
Blood transfusions may be necessary before operations, especially in the setting of active hemorrhage or profound anemia. However, transfusions have been associated with increased operative mortality and morbidity, decreased long-term survival, greater lengths of hospital stay, and higher chances of tumor recurrence due to immunosuppressive effects imparted by transfused blood. The benefits of transfusions must be balanced against their hazards. Of course, bleeding diatheses require preoperative correction, including transfusions of blood products such as fresh frozen plasma, specific clotting factors, or platelets. Hematology consultations are invaluable when blood incompatibilities or unusual factor deficiencies are present.
Preoperative nutritional status bears a major impact on outcome, especially with respect to wound healing and immune status. A multivariate analysis recognizes hypoalbuminemia (albumin < 3.0 mg/dL) as an independent risk factor for the development of SSIs, with a fivefold increased incidence versus patients with normal albumin levels, corroborating the results of previous studies. Among moderately to severely malnourished patients, efforts may be focused upon preoperative feedings, ideally via the gut, although at least 1 week of the regimen is necessary to confer benefit. Total parenteral nutrition is an option for select patients in whom the gut cannot be used, but it conveys potential hazards. Immune modulating nutrition (IMN), with agents such as l-arginine, l-glutamine, ω-3 fatty acids, and nucleotides, can enhance immune and inflammatory responses. A recent meta-analysis of randomized controlled trials suggests that perioperative IMN with open, elective gastrointestinal operations is associated with fewer postoperative complications and shorter lengths of hospital stay compared to results for patients with standard enteral nutrition. However, the value of preoperative IMN is not firmly established.
At the other end of the spectrum, investigators have demonstrated that severe obesity is associated with increased rates of postoperative mortality, wound complications, renal failure, and pulmonary insufficiency, as well as greater durations of operative time and hospital stays. The AHA has issued guidelines for the assessment and management of morbidly obese patients, including an obesity surgery mortality score for gastric bypass. Unfavorable prognostic elements include BMI ≥50 kg/m2, male sex, hypertension, PE risks (eg, presence of a VTE event, prior inferior vena cava filter placement, history of right heart failure or pulmonary hypertension, findings of venous stasis disease), and age ≥45 years. Bariatric surgeons typically enforce a preoperative regimen of weight reduction before proceeding with surgery to enhance outcomes and to assure the patient’s commitment to the process.
Endocrine deficiencies pose special problems. Patients may have either primary adrenal insufficiency or chronic adrenal suppression from chronic corticosteroid usage. Inadequate amounts of perioperative steroids can result in an Addisonian crisis, with hemodynamic instability and even death. The need for perioperative “stress” steroid administration is a function of the duration of steroid therapy and the degree of the physiologic stress imposed by the operation. Supplemental corticosteroids should definitely be administered for established primary or secondary adrenal insufficiency, for a current regimen of more than the daily equivalent of 20 mg of prednisone, or for those with a history of chronic steroid usage and a Cushingoid appearance. Perioperative steroids should be considered if the current regimen is 5 to 20 mg of prednisone for 3 weeks or longer, for a history of more than a 3-week course of at least 20 mg of prednisone during the past year, for chronic usage of oral and rectal steroid therapy for inflammatory bowel disease, or for a significant history of chronic topical steroid usage (> 2 g daily) on large areas of affected skin. Increased amounts of corticosteroids are not necessary for patients who have received less than a 3-week course of steroids. Patients having operations of moderate (eg, lower extremity revascularization or total joint replacement) and major (eg, cardiothoracic, abdominal, central nervous system) stress should receive additional corticosteroids as outlined in Table 3–7. Minor or ambulatory operations, including those under local anesthesia, do not require supplemental steroids. Excessive amounts of steroids can have adverse consequences, including increased rates of SSIs, so hydrocortisone should not be indiscriminately prescribed. Of course, glucose levels should be closely monitored while patients receive steroids. Conversely, patients with advanced Cushing syndrome require expeditious medical and perhaps surgical treatment due to the potential for rapid deterioration, including fungal sepsis. Cushing syndrome and pheochromocytomas are separately addressed in Chapter 33.
Table 3–7.Recommendations for perioperative corticosteroid management. ||Download (.pdf) Table 3–7. Recommendations for perioperative corticosteroid management.
|Type of Operation ||Corticosteroid Administration |
Example: inguinal hernia repair or operation under local anesthesia
|Take usual morning steroid dose; no supplementary steroids are needed. |
Moderate surgical stressa
Example: lower extremity revascularization, total joint replacement
Day of surgery: Take usual morning steroid dose.
Just before induction of anesthesia: Hydrocortisone 50 mg IV, then hydrocortisone 25 mg IV every 8 h × 6 doses (or until able to take oral steroids).
When able to take oral steroids, change to daily oral prednisone equivalent of hydrocortisone, or preoperative steroid dose if that dose was higher.
On the second postoperative day: Resume prior outpatient dose, assuming the patient is in stable condition.a
Major surgical stressa
Example: major cardiac, brain, abdominal, or thoracic surgery
Inflammatory bowel diseaseb
Day of surgery: Take usual morning steroid dose.
Just before induction of anesthesia: Hydrocortisone 100 mg IV, then hydrocortisone 50 mg every 8 h × 6 doses (or until able to take oral steroids).
On the second postoperative day: Reduce to hydrocortisone 25 mg q8h if still fasting, or oral prednisone 15 mg daily (or preoperative steroid dose if that was higher).
Postoperative day 3 or 4: Resume preoperative steroid dose if the patient is in stable condition.a
Thyrotoxicosis must be corrected to avoid perioperative thyroid storm. Management includes antithyroid medications (eg, methimazole or propylthiouracil) and beta-blockers; saturated solution of potassium iodide controls hyperthyroidism and reduces the vascularity of the gland in patients with Graves disease. On the other hand, significant hypothyroidism can progress to perioperative hypothermia and hemodynamic collapse and thus requires preoperative hormone replacement. This is normally accomplished with daily oral levothyroxine, but greater doses of IV thyroid hormone may be necessary to acutely reverse a significant deficit. Large goiters can affect the airway and require collaboration between surgeon and anesthesiologist, possibly including a review of imaging to demonstrate the extent and location (eg, substernal) of the goiter. When possible, computed tomography contrast should be avoided in patients with significant goiters as the iodine load may provoke thyrotoxicosis.
As the elderly demographic expands, surgeons are confronted with increasingly frail patients who have multiple comorbidities. Simple, noninvasive, yet focused elements from the patient’s history and physical examination serve as prognostic factors based upon the patient’s well-being or frailty. Makary has reported graded scores (allowing for BMI, height, and gender) that are predicated upon degree of weight loss, diminished dominant grip strength, self-reported description of exhaustion levels, and weekly energy expenditure in the course of routine activities, along with walking speed. Preoperative frailty is predictive of an increased chance of postoperative complications, prolonged lengths of hospital stay, and discharge to a skilled or assisted-living facility after having previously lived at home. A recent multivariate analysis demonstrated that among more than 58,000 patients undergoing colon resection, independent predictors of major complications were an elevated frailty index, an open (vs laparoscopic) operation, and ASA Class 4 or 5, but interestingly not wound classification or emergency status. The care of the elderly requires thoughtful considerations of their diminished physiologic reserve and tolerance of the insult of an operation. Interventions may include preoperative and early postoperative physical therapy, prospective discharge planning, and the introduction of elder-specific order sets. Simple scoring systems can provide valuable information for the surgeon to present to the patient and family so that they can anticipate the nature of the postoperative care and recovery, including potential transfer to a rehabilitation facility and long-term debility.
Illicit Drug & Alcohol Usage
The value of routine testing for the presence of illicit drugs, at least among patients with suggestive histories, is uncertain. The presence of drugs in blood or urine might result in a cancellation of an operation, particularly if it is not immediately required. Conversely, some clinicians are not concerned about proving recent drug usage as long as the patient does not exhibit current evidence of toxicity or a hypermetabolic state. The confirmation of illicit drug usage obviously heightens awareness about the possibility of postoperative withdrawal. In general, patients should be advised to refrain from taking illicit drugs for at least a couple of weeks before an operation. Similarly, a history of heavy alcohol consumption raises the possibility of a postoperative withdrawal syndrome, which can be associated with significant morbidity and even death. It is ideal if patients can cease drinking alcohol for at least one week before an operation. Regardless of whether the patient can suspend alcohol consumption, the surgeon must closely monitor for symptoms of withdrawal among these patients and consider the regular administration of a benzodiazepine during recovery to prevent or treat acute withdrawal.
Many patients undergo neoadjuvant therapy for malignancies involving the breast, esophagus, stomach pancreas rectum, soft tissues, and other sites. The surgeon is responsible for restaging the tumor before proceeding with a resection. In general, the interval between the completion of the external beam radiation and the operation is commensurate with the duration of the radiation therapy. Similarly, a reasonable amount of time should elapse after systemic therapy to permit restoration of bone marrow capacity and nutrition, to the extent possible. Angiogenesis inhibitors such as bevacizumab disrupt normal wound perfusion and healing. The duration of time between biological therapy and an operation is not firmly established. However, it is probably best to allow 4 to 6 weeks to elapse after treating with bevacizumab before proceeding with an operation, and the therapy should not be resumed until the wound is fully healed, perhaps 1 month later.
Emergency operations generally permit little time for risk reduction, although fluid and blood resuscitation can be instituted and antibiotics administered. Emergency operations among patients who have undergone chemotherapy within the past month are associated with increased rates of major complications and death. In patients with profound neutropenia, operations should be deferred to the extent possible due to severely impaired wound healing and the likelihood of irreversible postoperative sepsis.