Preoperative cardiac risk assessment

Heart disease is the leading cause of mortality in the United States. An important subset of heart disease is perioperative myocardial infarction, which affects approximately 50,000 persons each year. The American College of Cardiology (ACC) and American Heart Association (AHA) have coauthored a guideline on preoperative cardiac risk assessment, as has the American College of Physicians (ACP). The ACC/AHA guideline uses major, intermediate, and minor clinical predictors to stratify patients into different cardiac risk categories. Patients with poor functional status or those undergoing high-risk surgery require further risk stratification via cardiac stress testing. The ACP guideline also starts by screening patients for clinical variables that predict perioperative cardiac complications. However, the ACP did not feel there was enough evidence to support poor functional status as a significant predictor of increased risk. High-risk patients would sometimes merit preoperative cardiac catheterization by the ACC/AHA guideline, while the ACP version would reserve catheterization only for those who were candidates for cardiac revascularization independent of their noncardiac surgery. A recent development in prophylaxis of surgery-related cardiac complications is the use of beta blockers perioperatively for patients with cardiac risk factors.     

Preoperative screening for perioperative cardiac risk

Preoperative screening for potential cardiac complications is crucial in making rational decisions about surgery. A number of classification schemes are available to aid the primary care physician in assessing a patient's perioperative cardiac risk. In general, these schemes enable the physician to place patients in low-risk, moderate-risk and high-risk categories. Patients at low risk can often be safely referred for surgery with minimal preoperative evaluation, while those at potentially high risk frequently need further assessment and medical or surgical treatment of cardiac disease prior to surgery. The classification schemes are most accurate in identifying patients at high risk for perioperative cardiac complications. However, patients with silent underlying cardiac disease are often underclassified with respect to potential risk. For those patients, accurate prediction of perioperative cardiac complications can be challenging.     

Perioperative cardiac risk reduction

Cardiovascular complications are the most common cause of perioperative morbidity and mortality. Noninvasive stress testing is rarely helpful in assessing risk, and for most patients there is no evidence that coronary revascularization provides more protection against perioperative cardiovascular events than optimal medical management. Patients likely to benefit from perioperative beta blockade include those with stable coronary artery disease and multiple cardiac risk factors. Perioperative beta blockers should be initiated weeks before surgery and titrated to heart rate and blood pressure targets. The balance of benefits and harms of perioperative beta-blocker therapy is much less favorable in patients with limited cardiac risk factors and when initiated in the acute preoperative period. Perioperative statin therapy is recommended for all patients undergoing vascular surgery. When prescribed for the secondary prevention of cardiovascular disease, aspirin should be continued in the perioperative period.     

Preparing the medically compromised patient for surgery

Preparing the medically compromised patient for surgery requires identifying and treating preoperative risk factors and anticipating postoperative complications. Preoperative evaluation of all patients should include careful screening for bleeding disorders and prior anesthetic complications and assessment of nutritional status. In addition, patients with preexisting cardiac, pulmonary, and endocrine problems must be identified, since these problems represent the greatest risk factors for postoperative complications. Perioperative care is more effective when directed at specific organ systems. Communication among internists, anesthesiologists, and surgeons promotes optimal treatment for surgical patients with medical illness.     

Perioperative cardiac evaluation: novel interventions and clinical challenges

Cardiac complications are one of the most important sources of morbidity and mortality after noncardiac surgery. In this review, we discuss the pathophysiology of postoperative cardiac complications and published risk indices and guidelines that allow an estimation of preoperative risk. Recent evidence has challenged the primary role of perioperative beta blockers as a risk reduction strategy. The highest level of evidence for their use is for patients with coronary artery disease or multiple risk factors undergoing vascular surgery. Beta blockers may provide no benefit or may be potentially harmful for low- and intermediate-risk patients and surgeries. For patients with contraindications to beta blockers, diltiazem and clonidine are alternative agents that reduce cardiac risk. Statins are emerging as another potential strategy to reduce cardiac risk, although the evidence is based primarily on retrospective analyses. Coronary artery revascularization does not reduce cardiac complications after noncardiac surgery among patients with stable coronary artery disease.     

Noncardiac surgery in the patient with heart disease

Optimal care of the patient with heart disease undergoing noncardiac surgery requires that the members of the surgical team, including anesthesiologist, internist-cardiologist, and surgeon, be familiar with the cardiovascular response to surgery, preoperative cardiac risk stratification, and the unique pathogenesis of cardiac complications that may occur in the perioperative period. Preoperative evaluation and computation of cardiac risk, anesthetic considerations, along with perioperative care of the patient with ischemic heart disease, valvular heart disease, congestive heart failure, arrhythmias and conduction disorders, and hypertension is discussed.     

Evaluation of surgical risk in patients with COPD

In this overview general risk factors for postoperative complications are discussed with special reference to pulmonary complications, which frequently occur in patients with chronic obstructive pulmonary disease (COPD). In a second part the functional evaluation of lung resection candidates is presented. Pulmonary complications are the most frequent cause of postoperative morbidity and mortality. Risk factors include: underlying respiratory disease, especially COPD, current smoking, duration of anaesthesia, type of surgical procedure (upper abdominal or thoracic surgery), age and obesity. The preoperative evaluation of patients at risk is discussed. For non-thoracic surgery preoperative pulmonary function testing and a preoperative chest radiograph are indicated for high-risk patients only, whereas they are mandatory for all lung resection candidates. There are no cut-off values in pulmonary function testing which would preclude non-thoracic surgical procedures. In patients with COPD, laparascopic procedures are recommended; and regional or epidural anaesthesia have less adverse effects on pulmonary function than general anaesthesia. Prevention of postoperative pulmonary complications includes smoking cessation at least eight weeks before surgery, and, if indicated preoperative treatment with antibiotics, beta2-agonists, steroids (steroid-trial) and intensive perioperative chest physiotherapy (incentive spirometry). The functional reserves of lung resection candidates is assessed with an algorithm based on the forced expiratory volume in one second (FEV1), the transfer factor of the lung for carbon monoxide (DLCO), and the maximal oxygen uptake on exercise (VO2max). In critical patients additional split function studies are necessary to estimate the remaining pulmonary function depending on the extent of resection.     

Preoperative pulmonary evaluation: identifying and reducing risks for pulmonary complications

Postoperative pulmonary complications are among the most common sources of morbidity in patients undergoing major surgery. For this reason, the preoperative patient evaluation should emphasize risk factors for pulmonary complications as well as for traditional cardiac complications, as the former are comparably frequent and associated with longer hospital stays. Procedure-related risk factors are more important than patient-related risk factors for predicting pulmonary events, but clinicians should assess both types of factors. Pulmonary function testing has a limited role and should not be the basis for denying surgery if the surgical indication is compelling. Strategies to reduce the risk of postoperative pulmonary complications include optimizing management of chronic lung disease before surgery, lung expansion maneuvers, pain control, and selective placement of nasogastric tubes.     

Abdominoperineal resection for rectal carcinoma: perioperative risk factors

This retrospective review of 37 cases of abdominoperineal resection for adenocarcinoma sought to correlate preoperative clinical characteristics and intraoperative events with the likelihood of subsequent development of specific complications in the postoperative period. Mortality was 3% (1/37), and the complication rate was 76% (28/37), with urologic (49% [18/37]) and pulmonary (30% [11/37]) complications being the most common. Significant perioperative risk factors included a history of cardiac disease, current cardiac medications, diabetes mellitus, an abnormal preoperative electrocardiogram, and extended operation. Factors not associated with an increased risk included age, sex, a history of pulmonary disorders, previous abdominal operations, operative time, and need for transfusions, management of the pelvic peritoneum, or perineal drainage. Such information should reliably identify high-risk patients and therefore should be useful for selecting such patients for palliative or other limited techniques of tumor control.     

Correlation of preoperative factors, severity of disease, type of oxygenator and perfusion times with mortality and morbidity of coronary bypass

Previous studies have related preoperative status and severity of disease to the outcome of coronary artery bypass surgery. Although increased perfusion and clamp times increase the risk of cardiac surgical procedures, the importance of these factors in relation to the patient's preoperative condition and the severity of disease has not previously been determined. In this study of 1078 patients, we examined the correlation between the patient's preoperative condition, the severity of coronary disease, and duration of perfusion and clamp time, and the type of oxygenator used with the mortality and morbidity associated with coronary artery bypass grafting. One-way analysis of variance and multiple correlation analysis showed that perfusion time, clamp time and nonclamp perfusion time correlated with mortality, perioperative infarction, the use of intra-aortic balloon pump, stroke, renal failure, pulmonary failure, infection, and leg wound complications (p less than 0.05). Perfusion time, clamp time and nonclamp perfusion time did not correlate with postoperative bleeding or sternal wound complications. Nonclamp perfusion time correlated more strongly than any other factor with mortality, perioperative infarction, the use of intra-aortic balloon pump, renal failure, pulmonary failure and infection (p less than 0.05). Clamp time correlated more than any other factor with the development of leg-wound complications (p less than 0.05). The use of a bubble rather than a membrane oxygenator was significantly related to mortality, stroke, infection and leg wound complications by one-way analysis of variance (p less than 0.05).(ABSTRACT TRUNCATED AT 250 WORDS)     

Preoperative Cardiac Risk Assessment and Medical Management for Noncardiac Surgery

Advanced practice nurses (APNs) often care for patients who have risks for postoperative cardiac complications and face noncardiac surgery. Surgical urgency determines the initial preoperative evaluation, and the immediate action before emergency surgery is to identify high-risk patients and provide appropriate risk reduction. An elective surgery in those with active cardiac disease should be postponed until cardiac evaluation and treatment are complete. Asymptomatic patients may be risk stratified, and the revised cardiac risk index is easy to use and widely adopted. APNs have the opportunity to assess patient risk and take appropriate actions to minimize cardiac complications.     

Intensive care of the patient following open abdominal aortic surgery

PURPOSE OF REVIEW: Abdominal aortic aneurysms still require open repair despite the advances that endovascular aneurysm repair has made in treating patients with significant operative risk. Older patients with significant comorbidities require open repair of their complex aneurysms when they fail to meet anatomic criteria for endovascular aneurysm repair. This review discusses the physiologic insult of abdominal aortic surgery. It aims to address which patients are the highest risk of postoperative morbidity, and advances in their intensive care unit management to reduce such morbidity. RECENT FINDINGS: Advanced age, chronic health dysfunction, emergency surgery, and multiple organ failure are independent predictors of postoperative mortality. Myocardial ischemia is the largest contributor to patient morbidity, with any rise in postoperative cardiac troponin I predicting increased in-hospital myocardial infarction and mortality. Highest-risk patients benefit most from optimizing perioperative cardiac status with beta-blockade. Perioperative treatment with fenoldopam may improve renal outcome. Tracheostomy to aid in weaning is associated with increased mortality but may improve outcome in patients with preoperative chronic obstructive pulmonary disease. SUMMARY: Demographic trends indicate that open aortic surgery will continue to be performed on older patients with complex aneurysms. Identifying patients at risk and optimizing their postoperative risk factors will improve outcomes.     

Nutritional aspects of preoperative management

The preoperative evaluation of the surgical patient should include a careful evaluation of the patient's nutritional status. A careful history and physical examination are appropriate and reliable means for evaluation of nutritional status. Patients with certain diagnoses, such as Crohn's disease or visceral malignancies, are likely to become malnourished even if they are not malnourished at the time of hospital admission. Preoperative and postoperative nutritional support, continued until the patient is able to take adequate nutrients by mouth, is an important part of the management of these patients and can improve the care and decrease the likelihood of complications.     

Preoperative Evaluation and Management of Patients With Select Chronic Gastrointestinal,Liver, and Renal Diseases

Patients with chronic gastrointestinal, hepatic, and renal disease are frequently encountered in clinical practice. This is due in part to the rising prevalence of risk factors associated with these conditions. These patients are increasingly being considered for surgical intervention and are at higher risk for multiple perioperative complications. Many are able to safely undergo surgery but require unique considerations to ensure optimal perioperative care. In this review, we highlight relevant perioperative physiology and outline our approach to the evaluation and management of patients with select chronic gastrointestinal, hepatic, and renal diseases. A comprehensive preoperative evaluation with a multidisciplinary approach is often beneficial, and specialist involvement should be considered. Intraoperative and postoperative plans should be individualized based on the unique medical and surgical characteristics of each patient.     

Outcome of cardiac surgery patients with complicated intensive care unit stay

Risk stratification has become an essential element in the practice of cardiac surgery. Several studies have identified preoperative risk factors for adverse outcome. However, outcome is mostly defined by 30-day mortality and morbidity. These data reflect poorly the benefit for the patient. Long-term survival, quality of life, and functional status should be included in a more global analysis of the outcome, particularly in patients with complicated ICU stay. By reviewing the recent data reported in the literature, we can identify a number of preoperative predictive factors for complicated ICU stay, including advanced age, chronic obstructive pulmonary disease, preoperative low ejection fraction, previous myocardial infarction, reoperation, renal failure, combined surgery (coronary artery bypass grafting plus valve surgery), low hematocrit, and neurologic impairment. Short- and long-term outcomes are dependent on the type of postoperative complication. Unfortunately, data regarding the long-term outcome in these situations are very scarce.     

A Cross-Validated Multifactorial Index of Perioperative Risks in Adults Undergoing Anaesthesia for Non-Cardiac Surgery

Objective. To develop a severity index of anaesthetic risk that predicts relevant perioperative adverse events in adults. Design. Prospective cross-sectional study. Setting. Department of anaesthesiology at one university hospital. Patients. 26907 consecutive anaesthetic procedures in patients over 15 years of age and a complete preoperative evaluation. Patients undergoing cardiac and obstetric surgery were excluded. Measurements and main results. Demographic data, preoperative health status, type of anaesthesia, operative procedures, and perioperative incidents (standardised on a national basis) were acquired by means of a computerised anaesthetic record system. Occurrence of at least one perioperative event with impact on postanaesthetic care was computed by a multivariate logistic regression model against 17 variables with different characteristics representing possible risk factors. Fourteen variables proved to be independent risk factors. The weighting of the variables was expressed in scores which added up to form a simple index for each patient. Patients without major risk factors (0–10 points) had a 0.3% risk of suffering from a relevant incident. Patients with more than 60 points had a 28.6% risk. The results were well demonstrated by cross-validation. Conclusions. The index seems to reflect the risk of relevant perioperative incidents. It can be used for audit purposes. In daily routine, the index could focus our attention on patients with increased perioperative risk. However, it is limited in detecting particular constellations of factors which interact on each other with regard to perioperative risk.     

Perioperative management of diabetes

Maintaining glycemic and metabolic control is difficult in diabetic patients who are undergoing surgery. The preoperative evaluation of all patients with diabetes should include careful screening for asymptomatic cardiac or renal disease. Frequent self-monitoring of glucose levels is important in the week before surgery so that insulin regimens can be adjusted as needed. Oral agents and long-acting insulin are usually discontinued before surgery, although the newer long-acting insulin analog glargine may be appropriately administered for basal insulin coverage throughout the surgical period. The usual regimen of sliding scale subcutaneous insulin for perioperative glycemic control may be a less preferable method because it can have unreliable absorption and lead to erratic blood glucose levels. Intravenous insulin infusion offers advantages because of the more predictable absorption rates and ability to rapidly titrate insulin delivery up or down to maintain proper glycemic control. Insulin is typically infused at 1 to 2 U per hour and adjusted according to the results of frequent blood glucose checks. A separate infusion of dextrose prevents hypoglycemia. Potassium is usually added to the dextrose infusion at 10 to 20 mEq per L in patients with normal renal function and normal preoperative serum potassium levels. Frequent monitoring of electrolytes and acid-base status is important during the perioperative period, especially in patients with type 1 diabetes because ketoacidosis can develop at modest levels of hyperglycemia.     

Perioperative evaluation and management of the patient with endocrine dysfunction

Whenever possible, endocrine disorders should be identified and evaluated prior to surgery. A plan for perioperative management of diabetes should be based on the type of diabetes, what diabetes medications are taken, the status of diabetes control, and what type of surgery is planned. Perioperative management of diabetes must include bedside glucose monitoring. Patients with mild hypothyroidism can safely proceed with elective surgery. Elective surgery should be postponed for patients with moderate or severe hypothyroidism. Patients who have mild hyperthyroidism can undergo elective surgery with preoperative beta blockade. Elective surgery should not be done on patients with moderate or severe hyperthyroidism until they are euthyroid. Patients with pheochromocytoma need to be identified and properly treated before surgery to prevent perioperative cardiovascular complications. Patients who take endogenous steroids should have the status of their HPA axis determined prior to surgery. If the patient is undergoing moderate or major surgical stress and has documented or presumed HPA suppression, then stress doses of steroids should be give perioperatively.     

Surgery in the patient with liver disease.

Patients with liver disease often undergo surgery. With the increasing prevalence of liver disease and improved survival due to newer medications and treatments, a growing number of patients with liver disease will require preoperative assessment. Because of the multiple physiological roles of the liver, hepatic dysfunction places these patients at an increased risk of perioperative morbidity and mortality. The precise risks associated with specific liver diseases are poorly understood but are greater with increased impairment of hepatic function. Identifying preexisting problems that could be optimally and appropriately managed before surgery (e.g., coagulation status, intravascular volume, renal function, electrolytes, cardiovascular status, and nutrition) may reduce these risks and decrease mortality in patients with liver disease undergoing surgery.     

AANA Journal course: update for nurse anesthetists--the preoperative pulmonary assessment: is this patient at high risk for surgery?

Postoperative pulmonary complications most often involve atelectasis followed by pneumonia and arterial hypoxemia. The severity of these complications is related to the decreases that occur in vital capacity and functional residual capacity. Astute anesthetists can prospectively identify patients and surgical procedures likely to be associated with pulmonary complications. Upper abdominal surgery carries a 30% to 40% pulmonary complication rate. Vertical laparotomies and lateral thoracotomies are associated with pulmonary risk, as are patients who are obese, emphysemic, asthmatic, or have cardiac disease. Optimal use of clinical data coupled with selective application of diagnostic tests, such as arterial blood gases and pulmonary function tests, help in the development of an appropriate anesthetic management plan that minimizes pulmonary risk, especially in patients with known pulmonary risk factors.