What investigations are required for pre-anesthesia checkups in patients of different ages and with various diseases, such as cardiovascular (CV) disease, respiratory disease, diabetes, hypertension (HTN), and renal failure?

Pre-Anesthesia Investigation Requirements by Age and Disease State

Preoperative tests should not be ordered routinely but rather on a selective basis guided by specific clinical characteristics, with the fundamental principle that testing is indicated only when results will guide or optimize perioperative management. 1

Core Principle: Selective Testing Based on Clinical Indications

The ASA Task Force explicitly states that preoperative tests should be ordered based on specific clinical characteristics rather than age or disease labels alone. 1 Global designations such as "preop status" or "surgical screening" are not considered specific clinical indications. 1

Electrocardiogram (ECG)

• Age alone is not an indication for ECG. 1
• Order ECG for patients with known cardiovascular risk factors including hypertension, previous myocardial infarction, coronary artery disease, or risk factors identified during preanesthesia evaluation. 1
• Consider ECG based on type of surgery when cardiovascular risk factors are present. 1
• ECG results from medical records are acceptable if obtained within 6 months and the patient's medical history has not changed substantially. 1

Advanced Cardiac Evaluation

Beyond ECG, cardiac evaluation (stress testing, echocardiogram, radionuclide imaging, cardiac catheterization) should balance risks and costs against benefits. 1

• Clinical characteristics to consider: cardiovascular risk factors and type of surgery. 1
• For patients with known CAD or new onset cardiac symptoms, baseline cardiac assessment should be performed. 1
• In asymptomatic patients ≥50 years, more extensive history and physical examination is warranted as cardiac risk indices were derived in this population. 1

Serum Chemistries (Potassium, Glucose, Sodium, Renal and Liver Function)

Order serum chemistries based on these specific clinical characteristics: 1

• Likely perioperative therapies (e.g., patients requiring fluid management, electrolyte replacement)
• Endocrine disorders (diabetes mellitus requiring glucose monitoring)
• Risk of renal dysfunction (chronic kidney disease, acute kidney injury risk)
• Risk of liver dysfunction (known liver disease, cirrhosis)
• Use of certain medications (diuretics, ACE inhibitors, digoxin requiring potassium monitoring)
• Alternative therapies that may affect electrolytes or organ function
• Extremes of age where laboratory values may differ from normal ranges 1

Diabetes-Specific Testing

• Glucose monitoring indicated for all patients with known diabetes or endocrine disorders. 1
• Consider HbA1c for assessment of glycemic control in diabetic patients undergoing major surgery. 2

Hypertension-Specific Testing

• Serum potassium indicated for patients on diuretics or other antihypertensive medications affecting electrolytes. 1
• Renal function studies indicated for patients with long-standing hypertension at risk for renal dysfunction. 1

Renal Failure-Specific Testing

• Comprehensive metabolic panel including potassium, sodium, creatinine, and BUN for all patients with known renal dysfunction. 1
• Consider coagulation studies as renal dysfunction affects platelet function and coagulation. 1

Hemoglobin/Hematocrit

Routine hemoglobin or hematocrit is not indicated. 1

Order hemoglobin/hematocrit for these specific indications: 1

• Type and invasiveness of procedure (major surgery with expected blood loss)
• Liver disease (risk of coagulopathy and anemia)
• Extremes of age (pediatric and geriatric populations)
• History of anemia
• History of bleeding disorders
• Other hematologic disorders

Coagulation Studies (INR, PT, PTT, Platelets)

Clinical characteristics requiring coagulation studies: 1

• Bleeding disorders (hemophilia, von Willebrand disease)
• Renal dysfunction (uremic platelet dysfunction)
• Liver dysfunction (impaired synthesis of clotting factors)
• Type and invasiveness of procedure (neurosurgery, major vascular surgery)
• Anticoagulant medications presenting additional perioperative risk 1
• Alternative therapies that may affect coagulation 1

Important caveat: The ASA Task Force acknowledges insufficient data regarding coagulation testing before regional anesthesia and recommends appropriately controlled studies. 1

Chest X-Ray

• Not routinely indicated but may be ordered based on cardiovascular or respiratory risk factors. 1
• Consider for patients with respiratory disease (COPD, asthma, active pulmonary infection). 1
• Chest x-ray results are acceptable if obtained within 6 months and medical history unchanged. 1

Urinalysis

Urinalysis is not indicated except for: 1

• Specific procedures: prosthesis implantation, urologic procedures
• Urinary tract symptoms present

Pregnancy Testing

Pregnancy testing may be considered for all female patients of childbearing age. 1

Clinical characteristics favoring pregnancy testing: 1

• Uncertain pregnancy history
• History suggestive of current pregnancy
• Recognition that history and physical examination may be insufficient for identifying early pregnancy 1

Age-Specific Considerations

Pediatric Patients

• No routine testing based on age alone. 1
• Testing guided by underlying medical conditions, surgical invasiveness, and specific risk factors. 3
• Many pediatric patients undergoing procedures are healthy and require minimal evaluation. 3

Geriatric Patients (≥65 years)

• Age alone does not mandate specific testing. 1
• More extensive assessment warranted in patients ≥50 years for cardiac risk stratification. 1
• Consider that laboratory values may differ from normal at extremes of age. 1
• Higher likelihood of cardiovascular disease, renal dysfunction, and polypharmacy requiring selective testing based on clinical characteristics. 1

Disease-Specific Testing Algorithms

Cardiovascular Disease

• ECG indicated for known cardiovascular risk factors. 1
• Advanced cardiac testing (stress test, echocardiogram) based on cardiovascular risk factors and type of surgery. 1
• Serum chemistries if on cardiac medications (diuretics, ACE inhibitors). 1
• Consider coagulation studies if on anticoagulants. 1

Respiratory Disease (COPD, Asthma)

• Chest x-ray for active pulmonary symptoms or significant disease. 1
• Arterial blood gas if oxygen saturation <95% on room air. 4
• Pulmonary function tests not routinely recommended by ASA guidelines but may be considered for optimization. 2

Diabetes Mellitus

• Glucose monitoring required. 1
• Serum chemistries including electrolytes and renal function. 1
• HbA1c for assessment of glycemic control in major surgery. 2
• ECG if cardiovascular risk factors present (common in diabetics). 1

Hypertension

• Serum potassium if on diuretics or other medications affecting electrolytes. 1
• Renal function studies for long-standing hypertension. 1
• ECG as hypertension is a cardiovascular risk factor. 1

Renal Failure

• Comprehensive metabolic panel (potassium, sodium, creatinine, BUN) mandatory. 1
• Hemoglobin/hematocrit for anemia of chronic kidney disease. 1
• Coagulation studies for uremic platelet dysfunction. 1
• ECG for associated cardiovascular disease and electrolyte abnormalities. 1

Timing of Preoperative Testing

Test results obtained within 6 months are generally acceptable if the patient's medical history has not changed substantially. 1

More recent test results may be desirable when: 1

• Medical history has changed
• Test results will influence selection of specific anesthetic technique (e.g., regional anesthesia with anticoagulation therapy)

Critical Pitfalls to Avoid

• Do not order tests routinely without specific clinical indications as this increases costs without improving outcomes. 1
• Do not use age alone as justification for testing particularly ECG in younger patients without risk factors. 1
• Do not ignore recent test results from medical records if obtained within 6 months and clinical status unchanged. 1
• Do not order coagulation studies routinely before regional anesthesia without specific bleeding risk factors. 1
• Do not perform urinalysis routinely except for prosthesis implantation or urologic procedures. 1
• Recognize that abnormal test results do not always lead to management changes and consider whether the test will actually influence perioperative care. 1