Preoperative Care

General Preoperative Evaluation

Basic evaluation

Preoperative care for elective surgical procedures is conducted in the outpatient setting.

Goals of the interview:

• To identify any current complaints
• To address hopes and expectations of planned surgery
• To relieve anxiety Anxiety Feelings or emotions of dread, apprehension, and impending disaster but not disabling as with anxiety disorders. Generalized Anxiety Disorder by answering questions
• To identify undiagnosed diseases
• To optimize pre-existing comorbidities Comorbidities The presence of co-existing or additional diseases with reference to an initial diagnosis or with reference to the index condition that is the subject of study. Comorbidity may affect the ability of affected individuals to function and also their survival; it may be used as a prognostic indicator for length of hospital stay, cost factors, and outcome or survival. St. Louis Encephalitis Virus

Medical history with emphasis on:

• Review of systems 
• Past medical history Past Medical History Adult Health Maintenance
• Past surgical history Past Surgical History Adult Health Maintenance
• Medications

Physical examination:

• Vital signs
• Cardiovascular examination Cardiovascular examination Examination of the cardiovascular system (CVS) is a critical component of a thorough physical examination. As with all components of a complete physical examination, the CVS examination consists of inspection, palpation, and auscultation. The evaluation of the CVS focuses on the heart, but also includes an assessment of the arterial system throughout the body. Cardiovascular Examination
• Respiratory examination 
• Surgery-related examination (e.g., suitability for positioning): assessment of comorbidities Comorbidities The presence of co-existing or additional diseases with reference to an initial diagnosis or with reference to the index condition that is the subject of study. Comorbidity may affect the ability of affected individuals to function and also their survival; it may be used as a prognostic indicator for length of hospital stay, cost factors, and outcome or survival. St. Louis Encephalitis Virus and their severity

Additional studies:

• CBC:
  • For patients Patients Individuals participating in the health care system for the purpose of receiving therapeutic, diagnostic, or preventive procedures. Clinician–Patient Relationship > 65 years of age who are scheduled for major surgery
  • Preoperative anemia Anemia Anemia is a condition in which individuals have low Hb levels, which can arise from various causes. Anemia is accompanied by a reduced number of RBCs and may manifest with fatigue, shortness of breath, pallor, and weakness. Subtypes are classified by the size of RBCs, chronicity, and etiology. Anemia: Overview and Types is associated with increased postoperative mortality Mortality All deaths reported in a given population. Measures of Health Status.
• Basic metabolic panel Basic Metabolic Panel Primary vs Secondary Headaches:
  • Routine measurement of electrolytes Electrolytes Electrolytes are mineral salts that dissolve in water and dissociate into charged particles called ions, which can be either be positively (cations) or negatively (anions) charged. Electrolytes are distributed in the extracellular and intracellular compartments in different concentrations. Electrolytes are essential for various basic life-sustaining functions. Electrolytes, glucose Glucose A primary source of energy for living organisms. It is naturally occurring and is found in fruits and other parts of plants in its free state. It is used therapeutically in fluid and nutrient replacement. Lactose Intolerance, or liver Liver The liver is the largest gland in the human body. The liver is found in the superior right quadrant of the abdomen and weighs approximately 1.5 kilograms. Its main functions are detoxification, metabolism, nutrient storage (e.g., iron and vitamins), synthesis of coagulation factors, formation of bile, filtration, and storage of blood. Liver: Anatomy enzymes Enzymes Enzymes are complex protein biocatalysts that accelerate chemical reactions without being consumed by them. Due to the body’s constant metabolic needs, the absence of enzymes would make life unsustainable, as reactions would occur too slowly without these molecules. Basics of Enzymes is not indicated.
  • Determination of creatinine levels recommended for patients Patients Individuals participating in the health care system for the purpose of receiving therapeutic, diagnostic, or preventive procedures. Clinician–Patient Relationship > 50 years of age who are scheduled for high- or intermediate-risk surgery
• Coagulation studies Coagulation studies Coagulation studies are a group of hematologic laboratory studies that reflect the function of blood vessels, platelets, and coagulation factors, which all interact with one another to achieve hemostasis. Coagulation studies are usually ordered to evaluate patients with bleeding or hypercoagulation disorders. Coagulation Studies: not routinely indicated
• Pregnancy Pregnancy The status during which female mammals carry their developing young (embryos or fetuses) in utero before birth, beginning from fertilization to birth. Pregnancy: Diagnosis, Physiology, and Care test: for all women of child-bearing age
• ECG ECG An electrocardiogram (ECG) is a graphic representation of the electrical activity of the heart plotted against time. Adhesive electrodes are affixed to the skin surface allowing measurement of cardiac impulses from many angles. The ECG provides 3-dimensional information about the conduction system of the heart, the myocardium, and other cardiac structures. Electrocardiogram (ECG): not indicated for healthy patients Patients Individuals participating in the health care system for the purpose of receiving therapeutic, diagnostic, or preventive procedures. Clinician–Patient Relationship < 45 of age
• Chest X-ray X-ray Penetrating electromagnetic radiation emitted when the inner orbital electrons of an atom are excited and release radiant energy. X-ray wavelengths range from 1 pm to 10 nm. Hard x-rays are the higher energy, shorter wavelength x-rays. Soft x-rays or grenz rays are less energetic and longer in wavelength. The short wavelength end of the x-ray spectrum overlaps the gamma rays wavelength range. The distinction between gamma rays and x-rays is based on their radiation source. Pulmonary Function Tests: 
  • Not routinely indicated
  • Recommended for patients Patients Individuals participating in the health care system for the purpose of receiving therapeutic, diagnostic, or preventive procedures. Clinician–Patient Relationship > 50 years of age scheduled for surgery for aortic aneurysm Aortic aneurysm An abnormal balloon- or sac-like dilatation in the wall of aorta. Thoracic Aortic Aneurysms, or in the case of upper abdominal or thoracic surgery Thoracic Surgery Basic surgical intervention in the thoracic cavity has the primary goal of alleviating any malady that mechanically affects the function of the heart and lungs, which can be secondary to underlying pathologies or, most commonly, trauma. Interventions include tube thoracostomy, thoracentesis, and emergency thoracotomy. Thoracic Surgery

Screening

Most healthy patients Patients Individuals participating in the health care system for the purpose of receiving therapeutic, diagnostic, or preventive procedures. Clinician–Patient Relationship do not need additional preoperative evaluation.

The goal of screening is to identify patients Patients Individuals participating in the health care system for the purpose of receiving therapeutic, diagnostic, or preventive procedures. Clinician–Patient Relationship with risk factors who may benefit from additional evaluation.

Specific factors that can influence postoperative outcomes:

• Age (minor risk factor)
• Medications
• Patient’s functional capacity (e.g., climbing stairs) using the metabolic equivalent task: 
  • 1 metabolic equivalent task: patient can complete basic daily activities such as using the bathroom and dressing
  • 4 metabolic equivalent tasks: the ability to walk up a flight of stairs or walk at 3–4 miles/hour (6.4 km KM KM is the substrate concentration at which half-maximal velocity (½ Vmax) is reached (KM is measured on the x-axis while ½ Vmax is measured on the y-axis). Enzyme Kinetics/hour)
  • 4–10 metabolic equivalent tasks: heavy housework, climbing 2 flights of stairs consecutively, heavy lifting
  • > 10 metabolic equivalent tasks: strenuous sports activities such as swimming, tennis, and basketball 
• Obesity Obesity Obesity is a condition associated with excess body weight, specifically with the deposition of excessive adipose tissue. Obesity is considered a global epidemic. Major influences come from the western diet and sedentary lifestyles, but the exact mechanisms likely include a mixture of genetic and environmental factors. Obesity
• Smoking Smoking Willful or deliberate act of inhaling and exhaling smoke from burning substances or agents held by hand. Interstitial Lung Diseases
• Illicit drug use
• Alcohol abuse
• Obstructive sleep apnea Obstructive sleep apnea Obstructive sleep apnea (OSA) is a disorder characterized by recurrent obstruction of the upper airway during sleep, causing hypoxia and fragmented sleep. Obstructive sleep apnea is due to a partial or complete collapse of the upper airway and is associated with snoring, restlessness, sleep interruption, and daytime somnolence. Obstructive Sleep Apnea
• Personal or family history Family History Adult Health Maintenance of anesthetic complications

Screening questionnaires:

• Identify patients Patients Individuals participating in the health care system for the purpose of receiving therapeutic, diagnostic, or preventive procedures. Clinician–Patient Relationship with pre-existing medical conditions that may increase perioperative risk and need further evaluation.
• One of the effective questionnaires consists of 17 questions and includes questions on:
  • Functional capacity (climbing 2 flights of stairs)
  • Heart disease
  • Thyroid Thyroid The thyroid gland is one of the largest endocrine glands in the human body. The thyroid gland is a highly vascular, brownish-red gland located in the visceral compartment of the anterior region of the neck. Thyroid Gland: Anatomy disease
  • Diabetes Diabetes Diabetes mellitus (DM) is a metabolic disease characterized by hyperglycemia and dysfunction of the regulation of glucose metabolism by insulin. Type 1 DM is diagnosed mostly in children and young adults as the result of autoimmune destruction of β cells in the pancreas and the resulting lack of insulin. Type 2 DM has a significant association with obesity and is characterized by insulin resistance. Diabetes Mellitus
  • Liver Liver The liver is the largest gland in the human body. The liver is found in the superior right quadrant of the abdomen and weighs approximately 1.5 kilograms. Its main functions are detoxification, metabolism, nutrient storage (e.g., iron and vitamins), synthesis of coagulation factors, formation of bile, filtration, and storage of blood. Liver: Anatomy disease
  • Renal insufficiency
  • Seizures Seizures A seizure is abnormal electrical activity of the neurons in the cerebral cortex that can manifest in numerous ways depending on the region of the brain affected. Seizures consist of a sudden imbalance that occurs between the excitatory and inhibitory signals in cortical neurons, creating a net excitation. The 2 major classes of seizures are focal and generalized. Seizures
  • Anesthetic complications
  • Asthma Asthma Asthma is a chronic inflammatory respiratory condition characterized by bronchial hyperresponsiveness and airflow obstruction. The disease is believed to result from the complex interaction of host and environmental factors that increase disease predisposition, with inflammation causing symptoms and structural changes. Patients typically present with wheezing, cough, and dyspnea. Asthma/bronchitis

Preoperative Cardiovascular Evaluation

Risk assessment and stratification

Patients Patients Individuals participating in the health care system for the purpose of receiving therapeutic, diagnostic, or preventive procedures. Clinician–Patient Relationship with a history or symptoms suggestive of heart disease need further assessment. Multiple algorithms for risk assessment have been developed. The revised cardiac Cardiac Total Anomalous Pulmonary Venous Return (TAPVR) risk index (RCRI) is the most practical and frequently used tool:

• 1 surgery-specific risk factor: high-risk procedures:
  • Vascular surgery
  • Open intraperitoneal procedures
  • Intrathoracic procedures
• 5 patient-specific risk factors:
  • Ischemic heart disease
  • Heart failure
  • Cerebrovascular disease
  • Insulin-dependent diabetes mellitus
  • Preoperative serum creatinine ≥ 2.0 mg/dL
• Patient stratification:
  • Patients stratified as “low risk” have no risk factors.
  • Patients stratified as “high risk” have 1 or more risk factors.

Indications for further testing

Low-risk patients Patients Individuals participating in the health care system for the purpose of receiving therapeutic, diagnostic, or preventive procedures. Clinician–Patient Relationship do not need further evaluation.

High-risk patients Patients Individuals participating in the health care system for the purpose of receiving therapeutic, diagnostic, or preventive procedures. Clinician–Patient Relationship are classified based on functional capacity:

• Metabolic equivalent tasks ≥ 4: no further testing
• Metabolic equivalent tasks <4: 
  • Pharmacologic stress test is performed.
  • Coronary revascularization Revascularization Thromboangiitis Obliterans (Buerger’s Disease) should be performed prior to surgery if results of the stress test warrant it.

Very high-risk patients Patients Individuals participating in the health care system for the purpose of receiving therapeutic, diagnostic, or preventive procedures. Clinician–Patient Relationship:

• Defined as:
  • MI MI MI is ischemia and death of an area of myocardial tissue due to insufficient blood flow and oxygenation, usually from thrombus formation on a ruptured atherosclerotic plaque in the epicardial arteries. Clinical presentation is most commonly with chest pain, but women and patients with diabetes may have atypical symptoms. Myocardial Infarction within 60 days of the planned procedure
  • Decompensated heart failure Heart Failure A heterogeneous condition in which the heart is unable to pump out sufficient blood to meet the metabolic need of the body. Heart failure can be caused by structural defects, functional abnormalities (ventricular dysfunction), or a sudden overload beyond its capacity. Chronic heart failure is more common than acute heart failure which results from sudden insult to cardiac function, such as myocardial infarction. Total Anomalous Pulmonary Venous Return (TAPVR)
  • Unstable angina Unstable angina Precordial pain at rest, which may precede a myocardial infarction. Stable and Unstable Angina
  • High-grade arrhythmias
  • Hemodynamically significant valve disease
• Very high risk of perioperative MI MI MI is ischemia and death of an area of myocardial tissue due to insufficient blood flow and oxygenation, usually from thrombus formation on a ruptured atherosclerotic plaque in the epicardial arteries. Clinical presentation is most commonly with chest pain, but women and patients with diabetes may have atypical symptoms. Myocardial Infarction and cardiac Cardiac Total Anomalous Pulmonary Venous Return (TAPVR) death
• Need referral to a cardiologist and maximal optimization prior to procedure

Risk-reduction strategies

• Optimization of medical therapy:
  • Beta-blockers Beta-blockers Drugs that bind to but do not activate beta-adrenergic receptors thereby blocking the actions of beta-adrenergic agonists. Adrenergic beta-antagonists are used for treatment of hypertension, cardiac arrhythmias, angina pectoris, glaucoma, migraine headaches, and anxiety. Class 2 Antiarrhythmic Drugs (Beta Blockers) 
  • Statins Statins Statins are competitive inhibitors of HMG-CoA reductase in the liver. HMG-CoA reductase is the rate-limiting step in cholesterol synthesis. Inhibition results in lowered intrahepatocytic cholesterol formation, resulting in up-regulation of LDL receptors and, ultimately, lowering levels of serum LDL and triglycerides. Statins
• Angiography Angiography Radiography of blood vessels after injection of a contrast medium. Cardiac Surgery and revascularization Revascularization Thromboangiitis Obliterans (Buerger’s Disease) for patients Patients Individuals participating in the health care system for the purpose of receiving therapeutic, diagnostic, or preventive procedures. Clinician–Patient Relationship with angina 
• Interventions on anatomic abnormalities such as valves

Preoperative Pulmonary Evaluation

Risk factors for postoperative pulmonary complications

• Age > 50 years
• Chronic obstructive pulmonary disease Pulmonary disease Diseases involving the respiratory system. Blastomyces/Blastomycosis ( COPD COPD Chronic obstructive pulmonary disease (COPD) is a lung disease characterized by progressive, largely irreversible airflow obstruction. The condition usually presents in middle-aged or elderly persons with a history of cigarette smoking. Signs and symptoms include prolonged expiration, wheezing, diminished breath sounds, progressive dyspnea, and chronic cough. Chronic Obstructive Pulmonary Disease (COPD))
• Chronic heart failure Heart Failure A heterogeneous condition in which the heart is unable to pump out sufficient blood to meet the metabolic need of the body. Heart failure can be caused by structural defects, functional abnormalities (ventricular dysfunction), or a sudden overload beyond its capacity. Chronic heart failure is more common than acute heart failure which results from sudden insult to cardiac function, such as myocardial infarction. Total Anomalous Pulmonary Venous Return (TAPVR) ( CHF CHF Congestive heart failure refers to the inability of the heart to supply the body with normal cardiac output to meet metabolic needs. Echocardiography can confirm the diagnosis and give information about the ejection fraction. Congestive Heart Failure)
• Current smoker
• Obstructive sleep apnea Obstructive sleep apnea Obstructive sleep apnea (OSA) is a disorder characterized by recurrent obstruction of the upper airway during sleep, causing hypoxia and fragmented sleep. Obstructive sleep apnea is due to a partial or complete collapse of the upper airway and is associated with snoring, restlessness, sleep interruption, and daytime somnolence. Obstructive Sleep Apnea
• Low O₂ saturation
• Pulmonary hypertension Pulmonary Hypertension Pulmonary hypertension (PH) or pulmonary arterial hypertension (PAH) is characterized by elevated pulmonary arterial pressure, which can lead to chronic progressive right heart failure. Pulmonary hypertension is grouped into 5 categories based on etiology, which include primary PAH, and PH due to cardiac disease, lung or hypoxic disease, chronic thromboembolic disease, and multifactorial or unclear etiologies. Pulmonary Hypertension
• Serum albumin Albumin Serum albumin from humans. It is an essential carrier of both endogenous substances, such as fatty acids and bilirubin, and of xenobiotics in the blood. Liver Function Tests < 3.5
• Functional dependence
• Poor general health status

Indications for pulmonary tests

• Chest X-ray X-ray Penetrating electromagnetic radiation emitted when the inner orbital electrons of an atom are excited and release radiant energy. X-ray wavelengths range from 1 pm to 10 nm. Hard x-rays are the higher energy, shorter wavelength x-rays. Soft x-rays or grenz rays are less energetic and longer in wavelength. The short wavelength end of the x-ray spectrum overlaps the gamma rays wavelength range. The distinction between gamma rays and x-rays is based on their radiation source. Pulmonary Function Tests: patients Patients Individuals participating in the health care system for the purpose of receiving therapeutic, diagnostic, or preventive procedures. Clinician–Patient Relationship > 50 years of age scheduled for an upper abdominal or thoracic procedure
• Pulmonary function tests:
  • Dyspnea Dyspnea Dyspnea is the subjective sensation of breathing discomfort. Dyspnea is a normal manifestation of heavy physical or psychological exertion, but also may be caused by underlying conditions (both pulmonary and extrapulmonary). Dyspnea
  • Exercise intolerance
  • History of asthma Asthma Asthma is a chronic inflammatory respiratory condition characterized by bronchial hyperresponsiveness and airflow obstruction. The disease is believed to result from the complex interaction of host and environmental factors that increase disease predisposition, with inflammation causing symptoms and structural changes. Patients typically present with wheezing, cough, and dyspnea. Asthma or COPD COPD Chronic obstructive pulmonary disease (COPD) is a lung disease characterized by progressive, largely irreversible airflow obstruction. The condition usually presents in middle-aged or elderly persons with a history of cigarette smoking. Signs and symptoms include prolonged expiration, wheezing, diminished breath sounds, progressive dyspnea, and chronic cough. Chronic Obstructive Pulmonary Disease (COPD), if the extent of impairment cannot be determined clinically
  • Patients Patients Individuals participating in the health care system for the purpose of receiving therapeutic, diagnostic, or preventive procedures. Clinician–Patient Relationship undergoing lung resections
  • Findings with increased risk:
    • Forced expiratory volume in 1 sec (FEV₁) < 70% of the predicted value
    • Forced vital capacity Vital capacity The volume of air that is exhaled by a maximal expiration following a maximal inspiration. Ventilation: Mechanics of Breathing (FVC) < 70% of the predicted value
    • FEV1/FVC ratio < 65%
• Arterial blood gas Arterial blood gas Respiratory Alkalosis (ABG): not routinely indicated for preoperative pulmonary evaluation
• Cardiopulmonary exercise test (CPET):
  • To calculate the maximum O₂ uptake and anaerobic ventilatory threshold Threshold Minimum voltage necessary to generate an action potential (an all-or-none response) Skeletal Muscle Contraction
  • Used in patients Patients Individuals participating in the health care system for the purpose of receiving therapeutic, diagnostic, or preventive procedures. Clinician–Patient Relationship with abnormal pulmonary function tests who are scheduled to undergo lung resection
  • The 6-minute walk test is an in-office option that correlates the risk and severity of postoperative complications Postoperative Complications Pathologic processes that affect patients after a surgical procedure. They may or may not be related to the disease for which the surgery was done, and they may or may not be direct results of the surgery. Postoperative Care.

System-specific Evaluations

Hepatic evaluation

• Postpone elective surgeries in case of acute hepatitis Acute Hepatitis Autoimmune Hepatitis. 
• In patients Patients Individuals participating in the health care system for the purpose of receiving therapeutic, diagnostic, or preventive procedures. Clinician–Patient Relationship with chronic liver Liver The liver is the largest gland in the human body. The liver is found in the superior right quadrant of the abdomen and weighs approximately 1.5 kilograms. Its main functions are detoxification, metabolism, nutrient storage (e.g., iron and vitamins), synthesis of coagulation factors, formation of bile, filtration, and storage of blood. Liver: Anatomy disease, risk assessment should be done based on the Child-Pugh classification and the model for end-stage liver Liver The liver is the largest gland in the human body. The liver is found in the superior right quadrant of the abdomen and weighs approximately 1.5 kilograms. Its main functions are detoxification, metabolism, nutrient storage (e.g., iron and vitamins), synthesis of coagulation factors, formation of bile, filtration, and storage of blood. Liver: Anatomy disease.
  • Child-Pugh C (decompensated cirrhosis Cirrhosis Cirrhosis is a late stage of hepatic parenchymal necrosis and scarring (fibrosis) most commonly due to hepatitis C infection and alcoholic liver disease. Patients may present with jaundice, ascites, and hepatosplenomegaly. Cirrhosis can also cause complications such as hepatic encephalopathy, portal hypertension, portal vein thrombosis, and hepatorenal syndrome. Cirrhosis) or model for end-stage liver Liver The liver is the largest gland in the human body. The liver is found in the superior right quadrant of the abdomen and weighs approximately 1.5 kilograms. Its main functions are detoxification, metabolism, nutrient storage (e.g., iron and vitamins), synthesis of coagulation factors, formation of bile, filtration, and storage of blood. Liver: Anatomy disease score > 15: Elective surgeries are contraindicated. 
  • Child-Pugh B (significant functional compromise) or model for end-stage liver Liver The liver is the largest gland in the human body. The liver is found in the superior right quadrant of the abdomen and weighs approximately 1.5 kilograms. Its main functions are detoxification, metabolism, nutrient storage (e.g., iron and vitamins), synthesis of coagulation factors, formation of bile, filtration, and storage of blood. Liver: Anatomy disease score of 10–15: Surgeries may be performed, but with caution.
  • Child-Pugh A (well-compensated cirrhosis Cirrhosis Cirrhosis is a late stage of hepatic parenchymal necrosis and scarring (fibrosis) most commonly due to hepatitis C infection and alcoholic liver disease. Patients may present with jaundice, ascites, and hepatosplenomegaly. Cirrhosis can also cause complications such as hepatic encephalopathy, portal hypertension, portal vein thrombosis, and hepatorenal syndrome. Cirrhosis) or model for end-stage liver Liver The liver is the largest gland in the human body. The liver is found in the superior right quadrant of the abdomen and weighs approximately 1.5 kilograms. Its main functions are detoxification, metabolism, nutrient storage (e.g., iron and vitamins), synthesis of coagulation factors, formation of bile, filtration, and storage of blood. Liver: Anatomy disease score < 10: Surgery is well tolerated.
• Complications of liver Liver The liver is the largest gland in the human body. The liver is found in the superior right quadrant of the abdomen and weighs approximately 1.5 kilograms. Its main functions are detoxification, metabolism, nutrient storage (e.g., iron and vitamins), synthesis of coagulation factors, formation of bile, filtration, and storage of blood. Liver: Anatomy diseases (e.g., thrombocytopenia Thrombocytopenia Thrombocytopenia occurs when the platelet count is < 150,000 per microliter. The normal range for platelets is usually 150,000-450,000/µL of whole blood. Thrombocytopenia can be a result of decreased production, increased destruction, or splenic sequestration of platelets. Patients are often asymptomatic until platelet counts are < 50,000/µL. Thrombocytopenia or decreased albumin Albumin Serum albumin from humans. It is an essential carrier of both endogenous substances, such as fatty acids and bilirubin, and of xenobiotics in the blood. Liver Function Tests levels) should be reversed prior to surgery, if possible.

Endocrine evaluation

• Diabetes Diabetes Diabetes mellitus (DM) is a metabolic disease characterized by hyperglycemia and dysfunction of the regulation of glucose metabolism by insulin. Type 1 DM is diagnosed mostly in children and young adults as the result of autoimmune destruction of β cells in the pancreas and the resulting lack of insulin. Type 2 DM has a significant association with obesity and is characterized by insulin resistance. Diabetes Mellitus mellitus:
  • HbA1c HbA1c Products of non-enzymatic reactions between glucose and hemoglobin a, occurring as a minor fraction of the hemoglobin components of human erythrocytes. Hemoglobin a1c is hemoglobin a with glucose covalently bound to the terminal valine of the beta chain. Glycated hemoglobin a is used as an index of the average blood sugar level over a lifetime of erythrocytes. Diabetes Mellitus and a metabolic panel should be ordered for patients Patients Individuals participating in the health care system for the purpose of receiving therapeutic, diagnostic, or preventive procedures. Clinician–Patient Relationship preoperatively.
  • Patients Patients Individuals participating in the health care system for the purpose of receiving therapeutic, diagnostic, or preventive procedures. Clinician–Patient Relationship with diabetes Diabetes Diabetes mellitus (DM) is a metabolic disease characterized by hyperglycemia and dysfunction of the regulation of glucose metabolism by insulin. Type 1 DM is diagnosed mostly in children and young adults as the result of autoimmune destruction of β cells in the pancreas and the resulting lack of insulin. Type 2 DM has a significant association with obesity and is characterized by insulin resistance. Diabetes Mellitus mellitus should be early on the operating room schedule due to their nil per os status.
  • Regular Regular Insulin insulin Insulin Insulin is a peptide hormone that is produced by the beta cells of the pancreas. Insulin plays a role in metabolic functions such as glucose uptake, glycolysis, glycogenesis, lipogenesis, and protein synthesis. Exogenous insulin may be needed for individuals with diabetes mellitus, in whom there is a deficiency in endogenous insulin or increased insulin resistance. Insulin:
    • Should be held when patients Patients Individuals participating in the health care system for the purpose of receiving therapeutic, diagnostic, or preventive procedures. Clinician–Patient Relationship are admitted prior to surgery and postoperatively when nil per os
    • Optimal serum glucose Glucose A primary source of energy for living organisms. It is naturally occurring and is found in fruits and other parts of plants in its free state. It is used therapeutically in fluid and nutrient replacement. Lactose Intolerance levels: 140–180 mg/dL
    • Monitored every 4 hours when nil per os
  • Long-acting insulin Insulin Insulin is a peptide hormone that is produced by the beta cells of the pancreas. Insulin plays a role in metabolic functions such as glucose uptake, glycolysis, glycogenesis, lipogenesis, and protein synthesis. Exogenous insulin may be needed for individuals with diabetes mellitus, in whom there is a deficiency in endogenous insulin or increased insulin resistance. Insulin:
    • Administer ⅔ of the home dose on the night before surgery.
    • Administer half the home dose on the day of surgery.
• Adrenal suppression Suppression Defense Mechanisms:
  • Chronic steroid therapy of > 5 mg prednisone Prednisone A synthetic anti-inflammatory glucocorticoid derived from cortisone. It is biologically inert and converted to prednisolone in the liver. Immunosuppressants daily for at least 3 weeks before surgery increases the risk for adrenal insufficiency Adrenal Insufficiency Conditions in which the production of adrenal corticosteroids falls below the requirement of the body. Adrenal insufficiency can be caused by defects in the adrenal glands, the pituitary gland, or the hypothalamus. Adrenal Insufficiency and Addison’s Disease during the perioperative period.
  • Moderate surgical stress:
    • 50 mg hydrocortisone Hydrocortisone The main glucocorticoid secreted by the adrenal cortex. Its synthetic counterpart is used, either as an injection or topically, in the treatment of inflammation, allergy, collagen diseases, asthma, adrenocortical deficiency, shock, and some neoplastic conditions. Immunosuppressants IV bolus before the induction of anesthesia Anesthesia A state characterized by loss of feeling or sensation. This depression of nerve function is usually the result of pharmacologic action and is induced to allow performance of surgery or other painful procedures. Anesthesiology: History and Basic Concepts
    • 25 mg hydrocortisone Hydrocortisone The main glucocorticoid secreted by the adrenal cortex. Its synthetic counterpart is used, either as an injection or topically, in the treatment of inflammation, allergy, collagen diseases, asthma, adrenocortical deficiency, shock, and some neoplastic conditions. Immunosuppressants every 8 hours for 24–48 hours
  • Major surgical stress:
    • 100 mg hydrocortisone Hydrocortisone The main glucocorticoid secreted by the adrenal cortex. Its synthetic counterpart is used, either as an injection or topically, in the treatment of inflammation, allergy, collagen diseases, asthma, adrenocortical deficiency, shock, and some neoplastic conditions. Immunosuppressants IV bolus before the induction of anesthesia Anesthesia A state characterized by loss of feeling or sensation. This depression of nerve function is usually the result of pharmacologic action and is induced to allow performance of surgery or other painful procedures. Anesthesiology: History and Basic Concepts
    • 50 mg hydrocortisone Hydrocortisone The main glucocorticoid secreted by the adrenal cortex. Its synthetic counterpart is used, either as an injection or topically, in the treatment of inflammation, allergy, collagen diseases, asthma, adrenocortical deficiency, shock, and some neoplastic conditions. Immunosuppressants every 8 hours for 24–48 hours
• Malnutrition Malnutrition Malnutrition is a clinical state caused by an imbalance or deficiency of calories and/or micronutrients and macronutrients. The 2 main manifestations of acute severe malnutrition are marasmus (total caloric insufficiency) and kwashiorkor (protein malnutrition with characteristic edema). Malnutrition in children in resource-limited countries: 
  • Nutritional support for 2 weeks prior to surgery for patients Patients Individuals participating in the health care system for the purpose of receiving therapeutic, diagnostic, or preventive procedures. Clinician–Patient Relationship who are malnourished
  • Clinically significant weight loss Weight loss Decrease in existing body weight. Bariatric Surgery:
    • > 10% over 6 months
    • > 5% over a 1-month period
  • Nutritional parameters:
    • Albumin Albumin Serum albumin from humans. It is an essential carrier of both endogenous substances, such as fatty acids and bilirubin, and of xenobiotics in the blood. Liver Function Tests
    • Prealbumin
    • Transferrin Transferrin An iron-binding beta1-globulin that is synthesized in the liver and secreted into the blood. It plays a central role in the transport of iron throughout the circulation. Heme Metabolism

Renal evaluation

• Preoperative creatinine > 2 mg/dL is an independent risk factor for postoperative cardiovascular complications.
• Patients Patients Individuals participating in the health care system for the purpose of receiving therapeutic, diagnostic, or preventive procedures. Clinician–Patient Relationship with known renal dysfunction should be ordered:
  • ECG ECG An electrocardiogram (ECG) is a graphic representation of the electrical activity of the heart plotted against time. Adhesive electrodes are affixed to the skin surface allowing measurement of cardiac impulses from many angles. The ECG provides 3-dimensional information about the conduction system of the heart, the myocardium, and other cardiac structures. Electrocardiogram (ECG)
  • Serum chemistry
  • CBC
• Patients Patients Individuals participating in the health care system for the purpose of receiving therapeutic, diagnostic, or preventive procedures. Clinician–Patient Relationship on dialysis Dialysis Renal replacement therapy refers to dialysis and/or kidney transplantation. Dialysis is a procedure by which toxins and excess water are removed from the circulation. Hemodialysis and peritoneal dialysis (PD) are the two types of dialysis, and their primary difference is the location of the filtration process (external to the body in hemodialysis versus inside the body for PD). Peritoneal Dialysis and Hemodialysis: Clarify when they were last dialyzed and check K⁺ levels preoperatively.

Hematologic evaluation

All patients Patients Individuals participating in the health care system for the purpose of receiving therapeutic, diagnostic, or preventive procedures. Clinician–Patient Relationship should be asked about a history of bleeding disorders Bleeding disorders Hypocoagulable conditions, also known as bleeding disorders or bleeding diathesis, are a diverse group of diseases that result in abnormal hemostasis. Physiologic hemostasis is dependent on the integrity of endothelial cells, subendothelial matrix, platelets, and coagulation factors. The hypocoagulable states result from abnormalities in one or more of these contributors, resulting in ineffective thrombosis and bleeding. Hypocoagulable Conditions or the use of anticoagulants Anticoagulants Anticoagulants are drugs that retard or interrupt the coagulation cascade. The primary classes of available anticoagulants include heparins, vitamin K-dependent antagonists (e.g., warfarin), direct thrombin inhibitors, and factor Xa inhibitors. Anticoagulants. Perioperative management differs significantly and is dependent on the indication and type of anticoagulant.

• Prosthetic heart valves:
  • High risk (recent stroke or transient ischemic attack Transient ischemic attack Transient ischemic attack (TIA) is a temporary episode of neurologic dysfunction caused by ischemia without infarction that resolves completely when blood supply is restored. Transient ischemic attack is a neurologic emergency that warrants urgent medical attention. Transient Ischemic Attack (TIA) ( TIA TIA Transient ischemic attack (TIA) is a temporary episode of neurologic dysfunction caused by ischemia without infarction that resolves completely when blood supply is restored. Transient ischemic attack is a neurologic emergency that warrants urgent medical attention. Transient Ischemic Attack (TIA)) < 1 month; mitral valve Mitral valve The valve between the left atrium and left ventricle of the heart. Heart: Anatomy): strongly recommend bridging with a short-acting agent such as heparin or enoxaparin Enoxaparin Low-molecular-weight fragment of heparin, having a 4-enopyranosuronate sodium structure at the non-reducing end of the chain. It is prepared by depolymerization of the benzylic ester of porcine mucosal heparin. Therapeutically, it is used as an antithrombotic agent. Anticoagulants sodium Sodium A member of the alkali group of metals. It has the atomic symbol na, atomic number 11, and atomic weight 23. Hyponatremia
  • Moderate or low risk (bileaflet aortic valve Aortic valve The valve between the left ventricle and the ascending aorta which prevents backflow into the left ventricle. Heart: Anatomy): Consider bridging.
• Chronic atrial fibrillation Atrial fibrillation Atrial fibrillation (AF or Afib) is a supraventricular tachyarrhythmia and the most common kind of arrhythmia. It is caused by rapid, uncontrolled atrial contractions and uncoordinated ventricular responses. Atrial Fibrillation:
  • Bridging with enoxaparin Enoxaparin Low-molecular-weight fragment of heparin, having a 4-enopyranosuronate sodium structure at the non-reducing end of the chain. It is prepared by depolymerization of the benzylic ester of porcine mucosal heparin. Therapeutically, it is used as an antithrombotic agent. Anticoagulants sodium Sodium A member of the alkali group of metals. It has the atomic symbol na, atomic number 11, and atomic weight 23. Hyponatremia or heparin should be considered in all cases.
  • Bridging is strongly recommended in patients Patients Individuals participating in the health care system for the purpose of receiving therapeutic, diagnostic, or preventive procedures. Clinician–Patient Relationship with TIA TIA Transient ischemic attack (TIA) is a temporary episode of neurologic dysfunction caused by ischemia without infarction that resolves completely when blood supply is restored. Transient ischemic attack is a neurologic emergency that warrants urgent medical attention. Transient Ischemic Attack (TIA) and rheumatic mitral valve Mitral valve The valve between the left atrium and left ventricle of the heart. Heart: Anatomy disease
• Venous thromboembolism Thromboembolism Obstruction of a blood vessel (embolism) by a blood clot (thrombus) in the blood stream. Systemic Lupus Erythematosus ( VTE VTE Obstruction of a vein or veins (embolism) by a blood clot (thrombus) in the bloodstream. Hypercoagulable States):
  • High risk (bridging strongly recommended):
    • VTE VTE Obstruction of a vein or veins (embolism) by a blood clot (thrombus) in the bloodstream. Hypercoagulable States within 3 weeks of surgery
    • Active cancer
    • Antiphosopholipid antibody
  • Moderate risk (bridging should be considered):
    • VTE VTE Obstruction of a vein or veins (embolism) by a blood clot (thrombus) in the bloodstream. Hypercoagulable States in the past 6 months
    • VTE VTE Obstruction of a vein or veins (embolism) by a blood clot (thrombus) in the bloodstream. Hypercoagulable States with any interruption in anticoagulation Anticoagulation Pulmonary Hypertension Drugs
  • Low risk (no risk factors): optional bridging

Anesthesia Evaluation and Preoperative Preparation

Assessment of patient status

The American Association for Anesthesiologists Anesthesiologists Physicians specializing in anesthesiology. Anesthesiology: History and Basic Concepts classification system stratifies patients Patients Individuals participating in the health care system for the purpose of receiving therapeutic, diagnostic, or preventive procedures. Clinician–Patient Relationship for postoperative outcomes based on health status:

• Class I: normal and healthy patient
• Class II: mild systemic disease
• Class III: severe systemic disease that limits activity
• Class IV: incapacitating disease that is a constant threat to life
• Class V: patient not expected to survive for 24 h regardless of surgical intervention

Airway Airway ABCDE Assessment evaluation

• To assess the ease of intubation Intubation Peritonsillar Abscess and airway Airway ABCDE Assessment maneuvers 
• Assessed using the modified Mallampati score by looking into an open mouth

Antibiotic prophylaxis Antibiotic prophylaxis Use of antibiotics before, during, or after a diagnostic, therapeutic, or surgical procedure to prevent infectious complications. Surgical Infections for surgical site infections Infections Invasion of the host organism by microorganisms or their toxins or by parasites that can cause pathological conditions or diseases. Chronic Granulomatous Disease

• 1st-generation cephalosporins Cephalosporins Cephalosporins are a group of bactericidal beta-lactam antibiotics (similar to penicillins) that exert their effects by preventing bacteria from producing their cell walls, ultimately leading to cell death. Cephalosporins are categorized by generation and all drug names begin with “cef-” or “ceph-.” Cephalosporins ( cefazolin Cefazolin A semisynthetic cephalosporin analog with broad-spectrum antibiotic action due to inhibition of bacterial cell wall synthesis. It attains high serum levels and is excreted quickly via the urine. Cephalosporins) 
• Cefazolin Cefazolin A semisynthetic cephalosporin analog with broad-spectrum antibiotic action due to inhibition of bacterial cell wall synthesis. It attains high serum levels and is excreted quickly via the urine. Cephalosporins + metronidazole Metronidazole A nitroimidazole used to treat amebiasis; vaginitis; trichomonas infections; giardiasis; anaerobic bacteria; and treponemal infections. Pyogenic Liver Abscess for bowel surgery
• Allergy Allergy An abnormal adaptive immune response that may or may not involve antigen-specific IgE Type I Hypersensitivity Reaction to penicillin Penicillin Rheumatic Fever: 
  • Vancomycin Vancomycin Antibacterial obtained from streptomyces orientalis. It is a glycopeptide related to ristocetin that inhibits bacterial cell wall assembly and is toxic to kidneys and the inner ear. Glycopeptides
  • Clindamycin Clindamycin An antibacterial agent that is a semisynthetic analog of lincomycin. Lincosamides

Preoperative fasting

• 8 hours prior to surgery: no fried or fatty foods or meat
• 6 hours prior to surgery: no nonhuman milk, infant formula, light meal
• 4 hours prior to surgery: no breast milk
• 2 hours prior to surgery: nil per os

Fluid replacement

Provide maintenance fluid on the morning of surgery and continue intraoperatively: 1.5 mL/kg/hour will meet the maintenance fluid requirements for most patients Patients Individuals participating in the health care system for the purpose of receiving therapeutic, diagnostic, or preventive procedures. Clinician–Patient Relationship.

Medications