Preoperative Evaluation
The preoperative evaluation is a review of a patient’s physical condition in preparation for surgery. The history and physical examination are the foundation of this assessment and focus on identifying predisposing factors for cardiac and pulmonary complications and on determining a patient’s functional capacity to define fitness for surgery. The history and physical examination findings determine the need for additional laboratory or diagnostic testing if such evaluation changes the course of action or improves patient health and outcomes. Presurgical medical optimization, including proper subspecialty consultation, improves surgical outcomes in patients with coexisting diseases. Preoperative preparation and optimization efforts focus on identifying and mitigating modifiable risk factors to improve surgical and longitudinal outcomes while reducing healthcare costs.
Elements of Preoperative Evaluation
The essential component of the preoperative evaluation is the history, which details past and current medical and surgical status, family and genetic history, and documentation of tobacco, alcohol, and substance use. A detailed list of allergies and reactions, as well as previous anesthetic experiences, helps formulate the anesthetic plan. A complete 12-point review of systems identifies any undiagnosed or inadequately optimized disease. Cardiovascular and pulmonary diseases are the primary drivers of adverse perioperative outcomes and are the most relevant in determining fitness for anesthesia and surgery [Reference Gupta, Fernandes, Rao and Dhanpal1].
A focused preoperative physical examination includes, at a minimum, documentation of vital signs, including height and weight, with body mass index (BMI) calculation, and an assessment of the airway, lungs, and heart, and a basic neurologic examination. Unexpected abnormal findings on the physical examination, such as a new heart murmur or an unexplained decline in functional capacity, compel investigation before elective surgery.
Medication Reconciliation
A complete medication history, including current and new drug therapy and unusual reactions or responses to drugs, ensures safe perioperative care. Medications that provide physiologic homeostasis should be continued preoperatively. The decision to continue, discontinue, or modify chronic medication regimens requires thoughtful risk–benefit analysis. Polypharmacy is common in elderly patients, and the preoperative evaluation is an opportunity to identify and mitigate duplicated medications and those with cross-reactivity. This encounter is also an opportunity to ensure that appropriate stroke and cardiovascular risk reduction strategies, such as statin therapy, are in place.
Risk Stratification
Perioperative risk is determined by healthcare, patient, and socio-economic factors [Reference Aronson, Murray and Martin2]. Healthcare factors include elements specific to the type and magnitude of the surgical procedure and those encompassing anesthesia type and management techniques employed, such as goal-directed fluid therapy. Patient characteristics include fixed risk factors, such as age and genetics, and modifiable risk factors, such as smoking, nutrition status, and anemia. Perioperative outcomes are directly affected by social determinants of health, such as economic stability, physical environment, and level of education.
Deciding to have surgery is a complex consideration of risks, short- and long-term benefits, alternatives, and effects on longitudinal health. A primary goal of the preoperative evaluation is to make surgery safer by estimating the total risk relative to the benefits of proceeding with surgery and reducing modifiable risk. Communicating the risk to the patient, along with risk reduction strategies in the interest of shared decision-making, affects whether or not to proceed with surgery.
ASA Physical Status Classification
Originally intended to assess and communicate a patient’s preanesthesia medical comorbidities, the American Society of Anesthesiologists (ASA) physical status classification is a current standard of risk assessment and a mandated element of the preanesthetic evaluation by the Joint Commission. The ASA scoring system alone does not predict perioperative risks. When combined with other factors such as frailty and functional status, it demonstrates excellent risk prediction, and higher scores correlate with increased postoperative morbidity and mortality [Reference Knuf, Maani and Cummings3]. This scale is based solely on the presence of existing disease and does not consider the risk of the surgical procedure.
Cardiac
Cardiac functional status or capacity, expressed as metabolic equivalents (METs), is determined subjectively by assessment with a brief set of questions and has been thought to be positively associated with postoperative outcomes. Many risk models rely on this assessment. Achieving four METs of activity without symptoms is a good prognostic indicator of perioperative outcomes [Reference Fleisher, Fleischmann and Auerbach4]. A subjective assessment of functional status does not accurately identify patients with inadequate functional capacity or predict postoperative morbidity or mortality [Reference Wijeysundera, Pearse and Shulman5]. The Duke Activity Status Index (DASI) provides an objective assessment of functional capacity. Compared with cardiopulmonary exercise testing and subjective assessment of functional capacity, only DASI scores successfully predicted the primary outcomes of myocardial injury or death at 30 days. A DASI score of <34 is associated with an increased risk of 30-day death, myocardial infarction (MI), and moderate to severe complications [Reference Wijeysundera, Beattie and Hillis6].
All patients scheduled for noncardiac surgery should have an initial assessment of the percentage risk of a major adverse cardiac event (MACE) using validated models that include information from the history and physical examination, objective functional capacity score, electrocardiogram, laboratory studies, and planned procedure. The calculated risk aids the patient and perioperative specialists in weighing the risks and benefits and determining the optimal timing of surgery. The risk score guides decision-making as to whether the planned surgery should proceed without further preoperative cardiovascular testing or whether postponement for additional testing is indicated. Preoperative risk stratification is also instrumental in determining if a patient would benefit from preoperative coronary revascularization or consideration of a lesser-risk or nonsurgical alternative. The risk assessment occasionally uncovers undiagnosed problems or inadequately managed chronic conditions requiring optimization. The decision to pursue further cardiovascular testing considers both short- and long-term risk reductions.
The Revised Cardiac Risk Index (RCRI) or the American College of Surgeons National Surgical Quality Improvement Program (NSQIP) risk prediction tool are two commonly used risk indices. The RCRI is simpler and has been widely used and validated for many years. The NSQIP calculator is more complex, requiring calculation through an online algorithm. A more straightforward tool derived from the NSQIP database is the Gupta myocardial infarction or cardiac arrest (MICA) calculator. The newer Cardiovascular Risk Index (CVRI) is a validated model with higher discriminatory power than the RCRI [Reference Dakik, Chehab and Eldirani7]. For patients at low MACE risk (<1%), no further testing is indicated. For patients with higher MACE risk (>1%) and inadequate functional capacity (<4 METs), the question becomes whether further cardiovascular testing will change management and improve the outcome.
Pulmonary
Postoperative pulmonary complications adversely influence a patient’s postoperative course. They are a significant source of postoperative morbidity and mortality, resulting in substantial increases in healthcare resource utilization. Table 1.1 details the patient and surgical risk factors associated with postoperative pulmonary complications. The ARISCAT Risk Index is a commonly used risk prediction tool to identify patients at risk of postoperative pulmonary complications and likely to benefit from presurgical risk reduction interventions, such as increased physical activity and preoperative incentive spirometry. All available risk indices provide a reliable estimation of postoperative pulmonary complication risk, but the ARISCAT Risk Index is the most practical for preoperative assessment. The strongest predictor for postoperative pulmonary complications is poor functional capacity. Any history suggesting unrecognized chronic lung disease or heart failure, such as reduced functional capacity, unexplained dyspnea, or cough, requires further evaluation. Pulmonary function tests and routine chest X-rays do not appreciably add to risk stratification.
Table 1.1 Predictive risk factors for postoperative pulmonary complications
| Patient risk factors | Surgical risk factors |
|---|---|
|
|
a Factors assessed by the ARISCAT Risk Index.
Preoperative Optimization and Prehabilitation
Safe and efficient surgical and anesthesia practice requires a fit and medically optimized patient. Numerous epidemiological studies indicate that inadequate preoperative preparation is a significant contributory factor to the primary causes of perioperative morbidity and mortality. Postoperative morbidity is a significant surgical outcome in terms of economic consequences to healthcare institutions. Preoperative comorbidities, coupled with surgical complexity, predict adverse outcomes and increased healthcare resource utilization. Given preoperative time and resource limitations, it is reasonable to focus these efforts on patients at high risk of postoperative morbidity and mortality. Preoperative optimization and prehabilitation represent prudent economic strategies for reducing short- and long-term healthcare expenses and improving longitudinal population health.
Preoperative optimization is a process of clinician-managed interventions not directly involving patient effort or behavior modification, such as medication adjustment, glucose management, or anemia correction, designed to prepare the patient psychologically and physiologically to handle the stress of surgery. Prehabilitation differs from optimization and is the active preoperative process of enhancing a patient’s functional capacity to allow better tolerance of the stressors of surgery and recovery. Prehabilitation efforts implemented to improve postoperative outcomes involve lifestyle interventions, such as nutritional supplementation, physical exercise, stress reduction, and smoking cessation.
Coexisting Disease
Cardiac
Ischemic Heart Disease
Patients with coronary stents undergoing noncardiac surgery are at high MACE risk even when receiving perioperative antiplatelet therapy, and withholding one or both antiplatelet medications increases the risk of thrombosis. They are also at high risk of significant bleeding when one or both medications are continued. MACEs, including stroke, are mainly related to previous medical conditions and perioperative blood loss, and not to the surgery itself. In patients undergoing noncardiac surgery after a percutaneous coronary intervention (PCI) with second-generation drug-eluting stents, the incidence of MACEs, including death, MI, stent thrombosis, and the need for repeat revascularization, was highest in the first 6 months after the PCI [Reference Smith, Warner and Warner8]. Elective procedures should be delayed for at least 6 months in patients with drug-eluting stents, at least 30 days for those with bare-metal stents, and 14 days following balloon angioplasty to allow for uninterrupted dual antiplatelet therapy.
Hypertension
Perioperative hypertension is primarily a manifestation of acute or acute-on-chronic hypertension. Perioperative hypertension occurs mainly for two reasons: (1) worsening of chronic hypertension; or (2) a response to transient factors, such as pain, anxiety, or withholding of blood pressure medications. Hypertension is not a significant factor for determining perioperative cardiac risk, but it does contribute to several conditions that are, such as chronic renal disease and diastolic dysfunction. In the absence of acute end-organ dysfunction, there is little justification for case cancellation for blood pressures below 180/110 mmHg.
Isolated systolic hypertension (ISH) is the most common type of hypertension in the elderly. It is associated with a two- to fourfold increase in the risk of MI, left ventricular hypertrophy (LVH), renal dysfunction, stroke, and cardiovascular mortality. Characteristics of ISH include a widened pulse pressure and a systolic blood pressure of ≥140 mmHg, with a diastolic blood pressure of <90 mmHg. Elderly patients benefit significantly from therapies to reduce systolic blood pressure. The preoperative treatment of ISH risks diastolic hypotension and compromise of perfusion to vascular beds, and requires careful consideration.
Bioprosthetic and Mechanical Heart Valves
Anticoagulation management in the patient with a bioprosthetic or mechanical valve undergoing surgery considers the type, location, and number of prosthetic heart valves, planned surgical procedure and bleeding risk, and other patient risk factors for thromboembolism, and the planned procedure. The primary concern with interrupting anticoagulation is thromboembolism, which carries a 20% mortality rate and a 40% rate of significant disability [Reference Tan, Wall and Rosengart9]. The decision to interrupt anticoagulation and whether or not to bridge with low-molecular-weight heparin requires stratification of a patient’s risk of thromboembolism versus significant bleeding. Thromboembolism risk stratification tools, such as the BleedMAP and HAS-BLED scores, are useful in clinical decision-making. Patients undergoing procedures with associated low bleeding risk should be continued on their regular anticoagulation regimen. The thromboembolic risk is highest within the first three months of bioprosthetic or mechanical mitral valve replacement or repair. Noncardiac surgery should be deferred to avoid interruption of anticoagulation.
Heart Failure
Heart failure represents a spectrum of disease, and perioperative risk varies depending on where the patient is along the continuum. Risk is lowest for those patients with asymptomatic diastolic dysfunction where ejection fraction is preserved, and highest for those at the end-stage with reduced ejection fraction. The postoperative mortality risk is higher in patients with heart failure than in those with coronary artery disease, and elderly patients with heart failure have substantially higher risks of postoperative mortality and hospital readmission. The preoperative assessment goals for heart failure patients before noncardiac surgery include: assessing functional status; identifying asymptomatic patients who are at risk of developing heart failure in the postoperative period; determining whether heart failure patients are stable and optimally managed or showing signs and symptoms of decompensation; recognizing high-risk heart failure syndromes, including new-onset heart failure; and identifying comorbidities that impact the stability of heart failure in the postoperative period. The inability to achieve 4 METs functional capacity by walking four average-length city blocks and climbing two flights of stairs without experiencing symptomatic limitation was 71% sensitive and 47% specific for predicting severe postoperative complications. Given the critical prognostic implications of functional capacity to surgical outcomes, the New York Heart Association (NYHA) functional classification (see Table 1.2) categorizes heart failure patients based on functional capacity limitations and symptom development. Postoperative mortality increases with severity of the preoperative functional impairment, from 4% in NYHA class 1 to 67% in class IV.
Table 1.2 New York Heart Association functional classification
| NYHA class | Symptoms |
|---|---|
| I | No limitations of physical activity. Ordinary activity does not cause dyspnea, palpitations, or fatigue |
| II | Slight limitation of physical activity. Comfortable at rest, but ordinary physical activity results in dyspnea, palpitations, or fatigue |
| III | Pronounced limitation of physical activity. Comfortable at rest, but less-than-ordinary physical activity results in dyspnea, palpitations, or fatigue |
| IV | Unable to carry on any physical activity without discomfort. Symptoms of heart failure at rest. Discomfort increases with any physical activity |
Asymptomatic diastolic dysfunction is common in elderly and hypertensive patients and presents considerable perioperative challenges. Diastolic dysfunction is an underestimated disease and is independently associated with major adverse outcomes in patients undergoing both cardiac or noncardiac surgery. The most straightforward approach to recognizing asymptomatic left ventricular dysfunction is maintaining a high index of suspicion when a patient provides a history of risk factors or presents with particular physical signs, such as resting tachycardia or the presence of a fourth heart sound. Identification of suspicious signs and symptoms warrants prompt cardiology referral. A risk stratification model, such as the RCRI or NSQIP calculator, including heart failure as a procedural risk factor provides an accurate MACE risk assessment. Both models offer an estimation of MACEs, but the NSQIP calculator also provides estimates of several other adverse outcomes, such as postoperative pulmonary complications (PPCs) and expected length of stay.
Pulmonary
The ARISCAT index identifies patients at risk of PPC and guides preoperative optimization strategies, as described in Table 1.3. Those at low risk of PPCs benefit from simple recommendations, such as practicing good oral hygiene and early mobilization. Those patients at intermediate and high risk of PPCs benefit from preoperative incentive spirometry and increased activity and advanced lung-protective ventilation maneuvers. All patients undergoing general anesthesia benefit from low-tidal-volume ventilation strategies. The use of inhaled bronchodilators more than three times a day in patients with chronic lung disease warrants the preoperative addition of maintenance medications.
Table 1.3 Perioperative pulmonary risk mitigation strategies
| Low risk of PPC | Intermediate risk of PPC | High risk of PPC |
|---|---|---|
| Early mobilization | All of low maneuvers, plus: | All of low and intermediate maneuvers, plus: |
| Good oral hygiene | Postoperative incentive spirometry | 1–2 weeks of preoperative incentive spirometry |
| Optimization of chronic lung disease | Identification and communication of “increased risk” status | Increased postoperative surveillance |
| Smoking cessation counseling and resources | Regional anesthesia/analgesia, if applicable | |
| Lung-protective ventilation |
Tobacco, Marijuana, and Vaping Use
Smoking within 1 year of surgery is associated with increased postoperative complications, including poor wound healing, increased healthcare costs, increased hospitalization, and higher utilization of healthcare resources. Preoperative smoking cessation reduces the incidence of these complications and, when maintained long term, improves population health in general. Each week of smoking cessation before surgery decreases the complication risk by 19%, and cessation of one year or more reduces PPC risk to that of a nonsmoker [Reference Quan, Ouyang and Zhou10]. Preoperative smoking cessation counseling and nicotine replacement therapy increase the likelihood of long-term abstinence. Like the use of traditional tobacco, chronic marijuana use results in similar long-term effects to cigarette use. Preoperative abstinence, comparable to that seen with smoking cessation, leads to a reduction in the risk of adverse outcomes.
There has been an increase in the usage of electronic (e-)cigarettes in recent years. While e-cigarettes do not contain the harmful combustion by-products of traditional cigarettes, they contain toxic solvents, such as glycerol and propylene glycol, and chemical flavorings. Vaping by patients undergoing plastic surgery exhibited an increased risk of skin flap necrosis and death. Perioperative vaping instructions and cessation efforts are identical to those for tobacco users.
Pulmonary Hypertension
The preoperative preparation of patients with pulmonary hypertension is a multidisciplinary effort critical to a good outcome for these patients. It focuses on determining the severity of the disease and the adequacy of physiologic and pharmacologic compensation. All pulmonary hypertension medications continue throughout the day of surgery, including diuretics, angiotensin-converting enzyme inhibitors (ACEIs), and sildenafil, to prevent acute decompensation. Laboratory studies are indicated, based on patient physical status and medication management. An electrocardiogram identifies right ventricular hypertrophy and evidence of right heart strain, and recent echocardiography assesses right ventricular function and pulmonary artery pressures. Evidence of right ventricular failure warrants case delay for further medical management.
Obstructive Sleep Apnea
Patients with obstructive sleep apnea (OSA) have a two- to fourfold higher risk of perioperative complications than patients without OSA. Respiratory complications, such as desaturation and respiratory failure, are the most common. Undiagnosed severe OSA is significantly associated with an increased risk of 30-day postoperative cardiovascular complications [Reference Chan, Wang and Seet11]. Other perioperative complications include difficulty with airway management, cardiovascular complications, and postoperative delirium, all leading to higher resource utilization. Given the increasing prevalence and associated perioperative risks of OSA, the Society of Anesthesia and Sleep Medicine recommends screening all presurgical patients for OSA.
The STOP-Bang questionnaire is the best-validated tool for preoperative screening for OSA. Patients with zero to two positive responses are considered low risk; those with three or four are at intermediate risk, and those with ≥5 positive responses are at high risk of having OSA. An elevated serum bicarbonate increases the specificity of intermediate STOP-Bang scores. A high risk score of 5–8 was associated with an increased cardiovascular risk following surgery and intensive care unit (ICU) readmission. In contrast, a moderate risk score of 3 or 4 was associated with an increased risk of ICU readmission and wound infection. Most patients with known or suspected OSA may proceed to surgery without additional testing or treatment for OSA. However, select patients benefit from surgical delay for formal diagnosis by sleep study and for initiation of therapy or treatment optimization. Patients requiring further testing or treatment optimization are delayed at least one week for acclimation to the continuous positive airway pressure (CPAP) device or adjusted settings. Patients on CPAP therapy for OSA should continue treatment up to the day of surgery and bring their CPAP or other treatment devices on the day of surgery, including controllers for hypoglossal nerve stimulators.
Frailty
Although frailty is independent of chronological age, it is more prevalent in the geriatric population. Frailty is defined as a decrease in physiologic reserve exceeding that expected from advanced age alone and presents with an increased vulnerability to stressors. Sarcopenia, characterized by a decline in functional capacity with low muscle mass and strength, is a significant component of frailty. Sarcopenia measurement by preoperative grip strength, gait speed, or chair stand test provides an accurate diagnosis of the severity of frailty [Reference Dalton and Zafirova12]. Frailty predicts postoperative mortality and morbidity, including delirium, increased hospital stay, discharge to a skilled nursing facility, cognitive impairment, and functional decline [Reference Kim, Han and Jung13]. The preoperative evaluation of elderly patients requiring elective major surgery should include a frailty screen. Most assessment tools involve scoring based on specific comorbidities, dependence on others for daily living activities, malnutrition, and dementia, rather than on physical assessment alone. There are several validated frailty screening tools, such as the FRAIL scale (detailed in Table 1.4), but few methods of objective measurement. FRAIL scale scores range from zero to 5, and a score of zero represents robust health status and 1–2 a prefrail state, and 3–5 is consistent with frailty. A positive frailty screen is an indication for a comprehensive evaluation and intervention by a geriatric medicine specialist. Identification of preoperative frailty informs patient and family discussions and decision-making regarding surgical techniques and alternative treatments, postoperative recovery strategies, and expected outcomes. The prognosis of frail patients improves with shared decision-making, prehabilitation, and interdisciplinary geriatric co-management [Reference Alvarez-Nebreda, Bentov and Urman14].
| Description | Question | Score |
|---|---|---|
| Fatigue | “Have you felt fatigued for most or all of the time over the past month?” |
|
| Resistance | “Do you have difficulty climbing a flight of stairs?” |
|
| Ambulation | “Do you have difficulty walking one block?” |
|
| Illness | “Do you have any of these illnesses: hypertension, diabetes, cancer, chronic lung disease, heart attack, congestive heart failure, angina, asthma, arthritis, stroke, and kidney disease?” |
|
| Loss of weight | “Have you lost more than 5% of your weight in the past year?” |
|
Malnutrition
Preoperative malnutrition leads to immune system dysfunction and contributes to several adverse surgical outcomes, including increased susceptibility to wound infection, cognitive dysfunction, and poor wound healing. Patients with preoperative hypoalbuminemia, either alone or associated with chronic liver disease or congestive heart failure, are more likely to have postoperative complications such as infections, organ dysfunction, increased duration of mechanical ventilation and ICU stay, and mortality. BMI is not an accurate assessment of nutritional status.
Various screening tools exist to identify malnutrition preoperatively. The Nestlé Mini Nutritional Assessment Short Form (MNA-SF) is a validated screening tool which evaluates predictive parameters such as recent oral intake, weight loss, mobility, psychological stress, and neuropsychological problems, in addition to BMI or calf circumference. The sensitivity and specificity of the MNA-SF is 97.9% and 100%, with a diagnostic accuracy of 99% for predicting undernutrition [Reference Mays, Drummonds and Powers15]. The MNA-SF is easy to use and efficient, and minimally impacts workflow. A numerical score identifies patients as malnourished, at risk of malnutrition, or of normal nutritional status. Preoperative nutritional optimization includes supplementation with protein or immunonutrient solutions containing arginine and omega fatty acids. Benefits of preoperative dietary supplementation include reduced hospital stays, reduced need for critical care, and reduced postoperative infections, including pulmonary and surgical site infections in patients undergoing gastrointestinal cancer surgery [Reference Zhang, Najarali and Ruo16]. The Enhanced Recovery After Surgery (ERAS) Society strongly encourages complex carbohydrate loading before surgery, which reduces postoperative insulin resistance and length of stay.
Anemia
Anemia is not merely an independent predictor of adverse perioperative outcomes; it is a potent risk multiplier. The preoperative presence of anemia augments the inherent mortality risk of coexisting diseases, such as chronic kidney disease (CKD) and congestive heart failure. Anemia is widespread in surgical patients, with a reported incidence of up to 76%. Frequently, the anemia is undiagnosed. Consequently, anemia identified on preoperative evaluation is often ignored and accepted as a harmless deviation. Not only is anemia a modifiable preoperative condition, but it is also associated with decreased survival and higher rates of hospitalization, and is one of the strongest predictors of perioperative blood transfusions, an individual risk profile. A preoperative hemoglobin level <6 g/dL increases the risk of death at 30 days 26-fold, compared to a hemoglobin level of 12 g/dL [Reference Kumar17].
Iron deficiency is the most common cause of anemia and results from malabsorption or nutritional deficiency, or is medication-related. Oral iron supplementation initiated 4–6 weeks before a scheduled surgery generally results in an increase in reticulocyte count within 7–14 days and an increase in hemoglobin level of about 2 g/dL within 3 weeks. Patients who do not respond to oral iron or who are noncompliant due to gastrointestinal disturbance are candidates for intravenous iron therapy. Intravenous iron results in hemoglobin increases of 0.5–1.0 g dL−1 per week. The use of erythrocyte-stimulating factors concurrently with intravenous iron results in an even greater response, but has an increased incidence of venous thromboembolism. Other nutritional causes of anemia, such as vitamin B12 and folate deficiencies, are easily correctable with over-the-counter supplementation. Preoperative consultation with a hematologist helps manage other identified forms of anemia, such as hemolytic or anemia of chronic inflammation. Intravenous iron initiated after surgery does not reduce the incidence of a perioperative blood transfusion but does reduce the 30-day transfusion incidence.
Cognitive Dysfunction
Many geriatric patients present for surgery with cognitive impairment predisposing them to preventable adverse outcomes, such as delirium, falls, pneumonia, urinary tract infections, functional decline, and increased mortality. Cognitive impairment describes a patient’s current state, and usually presents as confusion, memory loss, decreased attention, disorientation, and mood changes. Dementia and delirium are the two most common forms of cognitive impairment, and Table 1.5 differentiates one from the other. Patients with preexisting dementia have an increased incidence of early postoperative mortality.
Table 1.5 Characteristics of dementia and delirium
| Dementia | Delirium | |
|---|---|---|
| Duration | Chronic, progressive condition | Hours to weeks |
| Onset | Chronic onset | Acute onset |
| Attention | Generally normal | Impaired or fluctuating |
| Memory | Long- and short-term memory impairment | Recent and immediate memory impairment |
| Alertness | Generally normal | Lethargic to hypervigilant |
| Thought pattern | Word-finding difficulty; poor judgment | Disorganized thinking; slow or accelerated thoughts |
Approximately one-third of hospitalized elderly patients experience delirium. Routine preoperative screening for cognitive impairment identifies at-risk patients and allows appropriate referral to a neurologist or geriatric medicine specialist. The six-item screen, noted in Table 1.6, is a brief screening tool for identifying patients with cognitive impairment by testing attention, short-term memory, and orientation. Its reliability is comparable to the full Mini-Mental State Examination. A score of 2 or higher suggests cognitive impairment and the need for further evaluation.
Diabetes
An overwhelming quantity of literature establishes a clear correlation between perioperative hyperglycemia and adverse surgical outcomes, including increased surgical site infections and mortality. The risk of postoperative complications and death is a function of both long-term glycemic control and the short-term severity of hyperglycemia on admission. Diabetic patients, particularly those requiring insulin management, undergoing major vascular surgery have a higher incidence of perioperative death and cardiovascular complications. Neither diabetes managed with insulin nor that managed with oral medications independently predicts mortality. Significant risk factors for death include several diabetes comorbidities, such as proteinuria, elevated creatinine level, history of congestive heart failure, and stroke. After adjusting for comorbidities, diabetic patients have a 38% or higher increase in hospital length of stay [Reference Axelrod, Upchurch and DeMonner18]. Preoperative risk stratification involves a basic metabolic panel within 6 months of the scheduled surgery, or more recent, depending on patient status. A hemoglobin A1c (Hgb A1c) level indicates long-term glucose control over the preceding 2–3 months, but there is no clear delineation of the level above which elective surgery should not occur. The ability of a preoperative Hgb A1c to predict surgical site infections remains controversial, but many orthopedic departments utilize a 7.0–8.5% range, above which elective surgery is delayed. Fructosamine levels are an alternative to Hgb A1c and provide an indication of glucose control over the past 2–3 weeks. Some literature suggests that fructosamine levels are a more significant predictor of adverse outcomes in orthopedic surgery than Hgb A1c. Fructosamine is useful for assessing glucose control in conditions where Hgb A1c is unreliable, such as end-stage renal disease (ESRD) and chronic hemolytic anemia.
Chronic Kidney Disease
The preoperative management of the spectrum of CKD, further detailed in Table 1.7, requires consideration of the disease process and comorbidities, such as cardiovascular dysfunction, anemia, and electrolyte disorders. These coexisting diseases confer significant perioperative risk. Of primary concern is the independent association with underlying coronary artery disease. Objective assessment of functional capacity with DASI and adherence to the American College of Cardiology (ACC)/American Heart Association (AHA) perioperative guidelines aid in risk assessment. ACEIs, angiotensin receptor blockers (ARBs), and diuretics are customarily held before surgery unless indicated for heart failure or volume overload. All other cardiovascular medications should continue as usual. ESRD patients have a high incidence of coexisting structural heart disease, and both right and left ventricular dysfunction are associated with poor outcomes and death. An echocardiogram obtained within the previous year is useful for risk stratification. Despite a high prevalence of coronary artery disease, many CKD patients are asymptomatic and have adequate functional capacity. An objective assessment of cardiac function, such as dobutamine stress echocardiography, identifies undiagnosed cardiovascular disease and allows for preoperative risk mitigation. CKD is associated with excess surgical morbidity, including acute renal failure, hyperkalemia, volume overload, and infections. Patients with ESRD have an adjusted all-cause mortality rate at least 10-fold higher than that of nonESRD patients.
| Stage of chronic kidney disease | Signs and symptoms | Percentage of normal kidney function (estimated GFR) |
|---|---|---|
| 1 | No symptoms, but coexisting disease present (diabetes, hypertension, obesity) | ≥90% (normal or increased GFR) |
| 2 | No symptoms, but proteinuria present | 60–89% (mildly reduced GFR) |
| 3 | Edema, fatigue, microalbuminuria, back pain | 30–59% (moderately reduced GFR) |
| 4 | Stage 3 symptoms plus nausea, vomiting, neuropathy, and loss of appetite | 15–29% (severely reduced GFR) |
| 5 | Stage 4 symptoms plus fatigue, weakness, anemia, thirst, cramps, skin discoloration, little to no urine output, and easy bruising/bleeding | <15% (kidney failure; dialysis dependent) |
GFR, glomerular filtration rate.
Decreased renal production of erythropoietin leads to anemia. The National Kidney Foundation suggests optimizing preoperative hemoglobin level to 11–12 g dL−1 with oral or intravenous iron and erythropoietin-stimulating agents. Hemodialysis, preferably on the day before surgery, corrects electrolyte abnormalities and platelet dysfunction. While there is no established upper limit for hyperkalemia, with differences in institutional policy and patient tolerance, a preoperative basic or comprehensive metabolic profile detects potassium and other electrolyte abnormalities.
Summary and Conclusion
Preoperative evaluation and optimization are an opportunity for anesthesia providers to enhance patient safety and outcomes and to create value in healthcare through the identification, risk stratification, and mitigation of modifiable risk factors. A systems-based, collaborative approach and application of high-yield preoperative interventions on modifiable risk factors integrate the quadruple aim of improved outcomes, improved clinical and patient experiences, and reduction in healthcare costs.
Review Questions
1. Which New York Heart Association (NYHA) class is assigned a patient with a history of heart failure who has slight limitation of physical activity and is comfortable at rest, but experiences dyspnea, palpitations, or fatigue with ordinary physical activity?
Class I
Class II
Class III
Class IV
2. Which of the following is a risk prediction tool commonly used to identify patients at risk of postoperative pulmonary complications?
Six-item screen
NSQIP surgical risk calculator
ARISCAT Risk Index
FRAIL scale
3. Which of the following is a patient risk factor for the development of postoperative pulmonary complications?
Poor functional capacity/frailty
Emergency surgical procedure
Surgery lasting >2 hours
Receipt of a perioperative blood transfusion
4. Which of the following laboratory tests is useful for assessing glycemic control over the preceding 2–3 weeks in end-stage renal disease (ESRD) patients?
Hemoglobin A1c
Comprehensive metabolic profile
Fructosamine
Phenylpropanolamine
Answers
A patient with a history of heart failure who experiences slight limitation of physical activity with dyspnea, palpitations, or fatigue on ordinary activity is assigned NYHA class II.
The ARISCAT Risk Index is a risk prediction tool used to identify patients at risk of postoperative pulmonary complications and to guide perioperative optimization strategies.
Poor functional capacity/frailty is a patient risk factor for postoperative pulmonary complications. The other choices are surgical risk factors.
Fructosamine levels assess glycemic control over the preceding 2–3 weeks, whereas hemoglobin A1c assesses glycemic control over the previous 2–3 months. Fructosamine levels give a more reliable estimation in patients with conditions such as ESRD and chronic hemolytic anemia.
