Pre-Operative Assessment

Table II.

Risk Factors for Postoperative Pulmonary Complications
Age > 60
Chronic obstructive lung disease (asthma is not a risk factor)
Congestive Heart Failure
Functional dependence (inability to perform activities of daily living)
At least mild systemic illness (American Society of Anesthesiologist’s Class 2 or higher)
Major thoracic or upper abdominal surgery (most other major operations are also associated with significant risk)
Operations > 4 hours long, emergency operations, or need for general anesthesia

There are no standards for determining when pulmonary risk is prohibitive.

2. Preoperative Testing: Preoperative testing generally adds little to clinical assessment of pulmonary risk. Routine testing is not recommended for patients undergoing non-lung resection surgery, but may be useful in selected situations:

• Chest radiography may be more useful in patients with known or suspect cardiopulmonary disease, especially if undergoing upper abdominal or thoracic surgery.

• Pulmonary function testing or spirometry may be useful to diagnose suspected lung disease. There is no spirometric parameter cut-off that makes non-lung resection surgery prohibitively risky.

• Serum albumin level <35 g/L predicts a higher risk of pulmonary complications. It is reasonable to measure albumin levels in patients suspected of having hypoalbuminemia.

3. Risk Reduction Strategies: The following strategies may reduce the risk of postoperative pulmonary complications.

• Lung expansion maneuvers (e.g., incentive spirometry or deep breathing exercises) have been shown to prevent complications in some studies.

• Smoking cessation may prevent pulmonary complications as well as wound complications. However, studies suggest that patients must quit smoking for 4-8 weeks before surgery to benefit.

• Patients with chronic lung disease should have their pulmonary function optimized prior to elective surgery.

• While it is reasonable to optimize nutritional status before non-urgent surgery, do not initiate enteral or parenteral nutrition solely to reduce pulmonary risk.

Perioperative Endocrine Issues

Diabetes Mellitus: Diabetic patients are increased risk for surgical site infections, and that risk correlates with the severity of diabetes. For elective operations, it is appropriate to assess the patient’s degree of glycemic control using hemoglobin A1c level or glucometer diary entries. Patients with very poor preoperative glucose control should postpone elective surgery until a more appropriate treatment regimen has been implemented. The inpatient management of diabetes (Glycemic Control of Hospitalized Patient) is described separately. Certain issues are particularly relevant for surgical patients:

• Hyperglycemia (due to high levels of counter-regulatory hormones) and hypoglycemia (due to NPO status or anorexia) are both frequently seen in surgical patients.

• Tight glycemic control may be beneficial in cardiac surgery patients in critical care units, but in other populations, it was associated with worse outcomes. In general, glycemic control targets for surgical patients should be the same as for nonsurgical patients.

• Type 1 diabetics require insulin regardless of their glycemic control. They should be managed with an insulin infusion when not eating in the perioperative period.

• Glucocorticoid therapy (commonly used in neurosurgical patients) can cause severe post-prandial hyperglycemia with relatively little effect on fasting glucose. Higher doses of meal-time insulin, rather than basal insulin, may be needed.

Adrenal Insufficiency: Patients with dysfunction of the hypothalamic-pituitary-adrenal axis (either due to intrinsic disease or suppression from exogenous glucocorticoid therapy) may be at risk for perioperative cardiovascular collapse. A common but unproven practice is to provide supplemental “stress-dose” steroids to patients with known or suspected adrenal insufficiency.

• Patients taking the equivalent of 20 mg of prednisone daily for 3 or more weeks may be at risk for adrenal insufficiency.

• Patients taking steroids for less than 3 weeks or at a daily dose of prednisone of 5 mg or less are unlikely to be at risk for perioperative adrenal insufficiency.

• Patients should continue their usual maintenance dose of steroids perioperatively.

• If supplemental glucocorticoids are given, a reasonable regimen is to give hydrocortisone 50 mg IV immediately prior to surgery, followed by hydrocortisone 25 mg IV every 8 hours for 24 hours.

Thyroid Disease: Patients with uncontrolled thyrotoxicosis can develop thyroid storm after surgery. An endocrinologist should be consulted if such patients require urgent or emergent surgery. Similarly, patients with severe, symptomatic hypothyroidism should delay elective surgery until adequate thyroid hormone replacement can be achieved. Mild or asymptomatic hypothyroidism is generally well tolerated during surgery.

Pheochromocytoma: This rare condition is described in a separate module. Patients with suspected pheochromocytoma should have this condition ruled out before undergoing all but emergency surgery. An endocrinologist should be consulted when a patient with known or suspected pheochromocytoma undergoes surgery.

Hematologic Issues

Anemia: The evaluation and management of anemia is described in detail in separate chapters. Anemia is commonly discovered preoperatively and develops routinely after surgery.

• Previously unrecognized anemia should be evaluated prior to elective surgery. For urgent surgery, undertake a limited assessment to rule out acute, potentially life-threatening processes such as hemorrhage or hemolysis.

• Severity of preoperative anemia correlates with postoperative mortality rates. However, it is not known whether correction of anemia prior to surgery improves outcomes. There is no specific preoperative hemoglobin level that should prompt transfusion. The decision to transfuse prior to surgery must also consider comorbidity (especially cardiopulmonary disease), the type of surgery, and the anticipated blood loss.

• Postoperative transfusion decisions must also be individualized. A limited number of studies failed to show that an aggressive transfusion strategy (e.g., keeping the hemoglobin > 10 mg/dL) leads to better outcomes than a more restrictive transfusion strategy.

Assessment of Bleeding Risk: The evaluation of specific disorders of hemostasis is described in detail in separate chapters. A directed bleeding history should be performed prior to surgery.

• Historical features suggesting an increased risk of bleeding include: unprovoked ecchymoses >5 cm on the trunk, menorrhagia with iron deficiency, frequent unprovoked epistaxis or gingival bleeding, hemarthrosis, prior excessive bleeding after surgery, personal or family history of bleeding diathesis, severe renal or liver disease, and use of medications that impair hemostasis.

• Laboratory testing (PT, aPTT, and platelet count) is not routinely needed, but should be considered if history is unreliable or suggests increased bleeding risk.

Management of Chronic Anticoagulation: While patients on chronic anticoagulation with warfarin must usually interrupt therapy prior to major surgery, those undergoing surgeries with low bleeding risk – such as minor skin surgery, cataract surgery, or minor dental surgery – may be able to continue warfarin in discussion with the surgical team. In cases where anticoagulation must be held, determination of thromboembolic risk helps to identify patients in which “bridging” with low molecular weight or unfractionated heparin may be indicated. The following recommendations are based on the 2012 American College of Chest Physician guidelines; some recommendations are not supported by strong evidence.

Recently, the BRIDGE Trial evaluated the utility of pre-operative “bridging” anticoagulation with low-molecular weight heparin (LMWH) in patients with atrial fibrillation and risk factors for stroke who were undergoing surgery. There was no significant difference in the incidence of arterial thromboembolism in patients who were bridged and those who were not bridged. However, the incidence of major bleeding was significantly higher in patients bridged with LMWH.

Management must be individualized to balance bleeding and thromboembolic risk, as well as consideration of patient and surgeon preferences. See Table III.

Table III.n

Evidence for perioperative management of oral direct thrombin and Xa inhibitors is lacking; an approach based largely on consensus and expert opinion is presented in Table IV. The rapid onset and offset of these agents generally makes bridging anticoagulation unnecessary.

Table IV.n

Surgery in Patients with Liver Disease

Clinical Risk Assessment: Patients with acute or chronic liver disease have an increased risk for complications, including bleeding, encephalopathy, renal failure, infection, and death. Preoperative clinical assessment should identify the presence and severity of liver disease symptoms.

• History and exam findings suggesting acute hepatitis should lead to delay or cancellation of elective surgery due to the observation of higher surgical mortality risk in such patients.

• Chronic hepatitis without evidence of decompensation or cirrhosis is generally not a contraindication to surgery.

• Severity of cirrhosis as measured by Childs-Turcotte-Pugh (CTP) classification correlates with surgical mortality. Surgery has generally acceptable mortality risk in CTP class A patients (<10%), worrisome risk in CTP class B patients (~30%), and prohibitive risk in class C patients (~70%).

• A risk prediction calculator based on MELD score that estimates both short-term and long-term postoperative mortality is available at http://www.mayoclinic.org/meld/mayomodel9.html

Preoperative Testing: Routine screening of liver enzyme levels is not recommended, but should be pursued in patients with suspected hepatitis. Calculation of CTP classification and MELD score requires measurement of serum albumin, total bilirubin, INR, and creatinine and should be done in patients with known or suspected cirrhosis. Further diagnostic testing and imaging studies depend on the specific clinical findings and the timing of surgery, and are described in other chapters.

Risk Reduction Strategies: In general, the management of cirrhosis in surgical patients is similar to its management in nonsurgical patients.

• Coagulopathy: Vitamin K may improve coagulopathy if nutritional deficiency is a contributing factor. Patients with severe coagulopathy may require fresh frozen plasma transfusion, usually aiming for INR of 1.5 or less. Patients with thrombocytopenia may require platelet transfusion, but response to transfusion may be limited in cirrhotic patients due to splenic sequestration.

• Ascites: Significant ascites can impair abdominal wound healing and impede respiratory mechanics. Elective surgery should be delayed until ascites can be controlled medically with diuretics. If surgery is urgent, consideration should be given to therapeutic paracentesis.

• Encephalopathy: Hepatic encephalopathy often worsens after surgery due to fluid/electrolyte imbalance and use of psychoactive analgesics and sedatives. Elective surgery should be delayed until encephalopathy is controlled with lactulose or antibiotics. It is not necessary to start these medications prophylactically in patients who don’t usually require them. Postoperatively, attention must be given to fluid and electrolyte balance, and the doses of analgesics and sedatives should be minimized.

IV. Common Pitfalls.

In performing preoperative medical assessments, be sure to avoid:

• “Clearing” the patient for surgery: The hospitalist should not assume sole responsibility for determining whether it is safe to proceed to surgery or state that the risk is low enough to operate. The aim of the preoperative assessment is to inform the surgeon and anesthesiologist about the patient’s risk for complications, in order to better weigh risks and benefits.

• Overstepping your qualifications: The generalist should not advise the anesthesiologist about anesthetic technique or intraoperative monitoring. Nor should the generalist advise the surgeon about surgical technique.

• Ordering unnecessary tests: For urgent or emergent surgery, prognostic testing will rarely influence medical decision-making and can needlessly delay surgery. Before ordering any preoperative tests, consider the likelihood of an abnormal result and determine how the results will change management.

• Failing to follow up: If the preoperative assessment identifies that the patient has substantial risk for medical complications, the hospitalist should follow up after the operation.

V. National Standards, Core Indicators and Quality Measures.

Severity quality assessment and improvement programs have been developed for surgical patients. Many of the core measurements in these programs deal with techniques to prevent infections that resulted directly from surgery, which is usually the responsibility of the surgeon and anesthesiologist, rather than the generalist/hospitalist (with the exception of endocarditis prophylaxis). Other core measures may be influenced by the actions of the consulting or comanaging hospitalist.

Process measures from the Surgical Care Improvement Project (SCIP) include:

• Perioperative beta-blocker usage in patients on these medications preoperatively

• Use of appropriate prophylaxis against venous thromboembolism after surgery

Postoperative outcome measures from the National Surgical Quality Improvement Program (NSQIP) include:

• Mortality

• Myocardial infarction

• Acute kidney injury

• Urinary tract infections

• DVT & PE

• Pulmonary complications (pneumonia or unplanned reintubation)

VI. What's the evidence?

Fleisher, LA, Fleischmann, KE, Auerbach, AD. “2014 ACC/AHA Guideline on perioperative cardiovascular evaluation and management of patients undergoing noncardiac surgery”. J Am Coll Cardiol.. vol. 64. 2014. pp. e77-e137.

Douketis, JD, Spyropoulos, AC, Kaatz, S. “Perioperative Bridging Anticoagulation in Patients with Atrial Fibrillation”. N Engl J Med.. vol. 373. 2015. pp. 823-833.

Douketis, JD, Spyropoulos, AC, Spencer, FA. “Perioperative Management of Antithrombotic Therapy. Antithrombotic Therapy and Prevention of Thrombosis, 9th ed: American College of Chest Physicians Evidence-Based Clinical Practice Guidelines”. Chest. vol. 141. 2012 April 1. pp. 1129

Ferrandis, R, Castillo, J, de Andrés, J. “The perioperative management of new direct oral anticoagulants: a question without answers”. Thromb Haemost. vol. 110. 2013. pp. 515-522.

Jørgensen, ME, Hlatky, MA, Køber, L. “β-blocker-associated risks in patients with uncomplicated hypertension undergoing noncardiac surgery”. JAMA Intern Med.. vol. 175. 2015. pp. 1923-31.

Qaseem, A, Snow, V, Fitterman, N. “Risk Assessment for and strategies to reduce perioperative pulmonary complications for patients undergoing noncardiothoracic surgery: a guideline from the American College of Physicians”. Ann Intern Med. vol. 144. 2006. pp. 575-580.

Teh, SH, Nagorney, DM, Stevens, SR. “Risk factors for mortality after surgery in patients with cirrhosis”. Gastroenterology. vol. 132. 2007. pp. 1261-9.

Lipshutz, AK, Gropper, MA.. “Perioperative glycemic control: an evidence-based review”. Anesthesiology. vol. 110. 2009. pp. 408-21.

Yong, SL, Marik, P, Esposito, M. “Supplemental perioperative steroids for surgical patients with adrenal insufficiency”. Cochrane Database Syst Rev.. Oct 7. pp. CD005367

Copyright © 2017, 2013 Decision Support in Medicine, LLC. All rights reserved.

No sponsor or advertiser has participated in, approved or paid for the content provided by Decision Support in Medicine LLC. The Licensed Content is the property of and copyrighted by DSM.