Evaluating the Patient Before Anesthesia

Jessie L. Cassada

Laurie Shapiro

I. OVERVIEW

The objectives of the preanesthetic evaluation include establishing rapport, becoming familiar with the patient’s surgical illness and coexisting medical conditions, medically optimizing the patient’s comorbidities, developing a management strategy for perioperative anesthetic care, and obtaining informed consent for the anesthetic plan. The consultation is then detailed in the patient’s medical record and concludes with the anesthetic options, including attendant risks and benefits of discussed options. The overall goals of the preoperative assessment are to reduce perioperative morbidity and mortality and to assuage patient anxiety.

II. HISTORY

Relevant information should be first obtained through chart review followed by corroboration with the patient interview. Prior knowledge of the patient’s history when beginning the interview is reassuring to the anxious patient. When the medical record is not available, a history obtained from the patient may be supplemented through discussions with the patient’s other physicians. Information gathered should include the following:

A. History of Presenting Illness. The anesthesiologist must comprehensively review the symptoms of the present surgical illness, presumptive diagnosis, initial treatment, response to treatment, and diagnostic studies.

B. Medications. The interviewer must establish the current dosing and schedules of all the patient’s medications. Of particular importance are antihypertensive, antianginal, antiarrhythmic, anticoagulant, anticonvulsant, and specific endocrine (e.g., insulin and hypoglycemics) medications. The decision to continue medication during the preoperative period depends on the severity of the underlying illness, the potential consequences of discontinuing treatment, the half-life of the medication, and the likelihood of deleterious interactions with proposed anesthetic agents. As a general rule, most medications may be continued up through the time of surgery (see section VI).

C. Allergies and Drug Reactions. True allergic reactions are relatively uncommon. Nonallergic adverse reactions to perioperative medications are not infrequent and may be perceived as an allergic reaction by the patient. Therefore, it is important to obtain a careful description of the exact nature of the reaction.

1. True allergic reactions. This can be presumed based upon a history of drug reaction that (by direct observation, chart documentation, or patient description) produced skin manifestations (pruritus with hives and/or flushing), facial or oral swelling, shortness of breath, choking, wheezing, or vascular collapse.

2. Antibiotic allergy. Allergies to antibiotics, especially to sulfonamides, penicillins, and cephalosporin derivatives, are the most common drug allergies. Notably, a patient reporting allergy is 90% to 99% likely not to be allergic when skin tested. With true penicillin allergy, there is a 2% to 4% cross-reactivity rate seen with first-generation cephalosporins. Cross-reactivity rates are lower for other generations.

3. Soybean oil and/or egg yolk allergy. Most egg allergies are to the white, rather than the yolk, and may not pose any anesthetic issues. Likewise, the vast majority of soy allergies are to the protein rather than to the oil and may not cause any complications. Use of propofol in a patient with these allergies is up to the discretion of the provider as current data on reactivity are mixed.

4. Inhalational agent or succinylcholine “allergy.” A history of allergy to “anesthesia,” inhalational agents, or succinylcholine (in the patient or any close relative) warrants special attention as this may represent a history of malignant hyperthermia (which is of autosomal dominant inheritance) or prolonged paralysis caused by atypical plasma cholinesterase (see Chapter 13). The metabolism of halothane has been associated with severe hepatitis. Although halothane is no longer used in most countries, it is still an anesthetic in Argentina, Brazil, Greece, India, Russia, and Turkey.

5. Local anesthetic allergy. Allergy to ester-type local anesthetics can be anaphylactic (see Chapter 16), while true allergy to the amide-type local anesthetics is exceedingly rare. Syncopal episodes, tachycardia, or palpitations associated with the injection of a local anesthetic/epinephrine preparation may be falsely labeled as an allergic reaction.

6. Shellfish or seafood allergy. Neither shellfish nor seafood allergy has been linked to an allergy to intravenous iodine contrast. (It had been presumed that shellfish allergies stemmed from high levels of iodine in the shellfish, but this has proven not true.) However, a history of dermatitis after exposure to topical iodine may preclude the use of intravenous iodine.

7. Latex allergy or hypersensitivity reactions. Latex allergy must be ascertained preoperatively to allow for preparation of a latex-free operating room. Additionally, banana, avocado, chestnut, apricot, kiwi, or papaya allergy should be elicited as 30% to 50% of individuals with these allergies have cross-reactive allergies to latex. Other risk factors for latex allergy include repeated exposure to latex (e.g., health care workers or patients with multiple prior surgeries), atopy, and certain medical disorders, such as spina bifida. If these risk factors exist, and no prior skin or serologic tests have been conducted, extra precautions may be warranted.

8. Adverse reactions and side effects. Many perioperative medications are capable of producing memorable and unpleasant side effects (e.g., nausea, vomiting, pruritus) in the conscious patient, but these are not true drug allergies.

D. Anesthetic History. Question the patient regarding his or her experience with prior anesthetics, including common complaints, such as postoperative nausea and vomiting (PONV), hoarseness, myopathy, or neuropathy.
Also examine the patient’s medical record for specific cautions from previous anesthesiologists. Additionally, review previous anesthetic records for the following information:

1. Response to medications. Patient response to sedative, analgesic, and anesthetic agents varies widely among individuals.

2. Vascular access and invasive monitoring. Determine that which has been used in the past, as well as any difficulties encountered.

3. Airway management. Determine past ease of mask ventilation, view obtained on direct laryngoscopy, size and type of laryngoscope blade and endotracheal tube, and depth of endotracheal tube insertion.

4. Perianesthetic complications. Review for complications such as adverse drug reactions, intraoperative awareness, dental injury, protracted PONV, hemodynamic issues, respiratory issues, postoperative myocardial infarction (MI), congestive heart failure, unexpected admission to an intensive care unit (ICU), prolonged emergence, or need for reintubation.

5. Narcotic requirements. Narcotic administration both intraoperatively and in the postoperative recovery unit is useful information, which will lend insight into future requirements.

E. Family History. A history of adverse anesthetic outcomes in family members should be assessed with open-ended questions, such as “Has anyone in your family experienced unusual or serious reactions to anesthesia?” Additionally, patients should be specifically asked about a family history of malignant hyperthermia.

F. Social History and Habits

1. Smoking. Although the complications of smoking may place the patient at a higher risk for perioperative pulmonary complications, cigarette smoking, itself, is no longer viewed as a major risk factor. Patients should, however, be counseled about smoking cessation as recent data have shown that patients are more likely to make a commitment to stop smoking around life-changing events, such as major surgery. A history of exercise intolerance or the presence of a productive cough or hemoptysis may indicate the need for further evaluation.

2. Drug and alcohol use. Although self-reporting of drug and alcohol intake typically underestimates use, it is a helpful start to define the type of drugs used, routes of administration, frequency, and timing of most recent use. Stimulant abuse may lead to palpitations, angina, weight loss, and lowered thresholds for serious arrhythmias and seizures. Acute alcohol intoxication decreases anesthetic requirement and predisposes to hypothermia and hypoglycemia. Alcohol withdrawal may precipitate severe hypertension (HTN), tremors, delirium, and seizures and may markedly increase anesthetic and analgesic requirements. Risk of intraoperative awareness is also increased with chronic opioid or benzodiazepine use.

III. REVIEW OF SYSTEMS

The purpose of review of systems is to elicit symptoms of occult disease and to determine the stability of current disease processes. Coexisting illnesses may complicate the surgical and anesthetic course. These illnesses should be evaluated in a systematic organ systems approach with an emphasis on recent changes in symptoms, signs, and treatment (see, also, Chapters 2 through 6). In certain circumstances, preoperative specialty consultation may be needed to answer specific questions about the interpretation of unusual laboratory tests, unfamiliar drug therapies, or changes in the patient’s baseline status.
Consultants should not be asked for a general “clearance” for anesthesia because this is the specific responsibility of the anesthesiologist. A minimum review of systems should seek to elicit the following information:

A. Cardiovascular.

1. Coronary artery disease. Preexisting coronary artery disease (CAD) may predispose the patient to myocardial ischemia, ventricular dysfunction, or MI with the stress of surgery and anesthesia. Elicitation of symptoms of angina, dyspnea on exertion (DOE), paroxysmal nocturnal dyspnea, and an assessment of the patient’s exercise capacity can help characterize the severity of disease.

2. Pacemakers and implanted cardioverter-defibrillators. Pacemakers and/or cardioverter-defibrillator devices implanted for a history of rhythm disturbances require consultation with an electrophysiologist. It is recommended that the device be interrogated within 6 months of surgery. The decision to leave on or deactivate (via transcutaneous magnet placement) the defibrillating mode should be made preoperatively.

3. Hypertension. Poorly treated HTN is frequently associated with blood pressure lability during anesthesia. Uncontrolled HTN is also considered a minor risk factor for perioperative major adverse cardiac events.

4. Dyspnea on exertion. DOE is an important sign that can be caused by myriad underlying etiologies, including physical deconditioning, obesity, or cardiopulmonary pathology. Knowledge of the latter is of great import for obvious reasons. If the DOE is chronic, it may prove prudent to contact the patient’s primary care provider, as often this provider will have insight regarding the etiology. If the DOE is an acute change from baseline, it is advisable to refer the patient to cardiology for further evaluation.

5. Exercise capacity. Although patient age and American Society of Anesthesiologists (ASA) physical status classification are more accurate predictors of adverse outcomes, knowledge of the patient’s activities of daily living, including maximum activity level, may help predict overall outcome in the perioperative period.

B. Respiratory.

1. Upper respiratory infection. Upper respiratory infection (URI), especially in children, can predispose patients to pulmonary complications including bronchospasm and laryngospasm during induction and emergence from general anesthesia. The patient with current signs and symptoms of a URI (e.g., productive cough, rhinorrhea, sore throat, fever) may benefit from postponement of an elective procedure.

2. Asthma. Reactive airway disease may result in acute bronchospasm in the perioperative period. Specific questions about previous asthmarelated hospitalizations, intubations, emergency room visits, and medication requirement (specifically, steroid use) can help delineate the severity of asthma.

3. Obstructive sleep apnea. Symptoms of obstructive sleep apnea (OSA) should be elicited as they may lead to intermittent perioperative hypoxia in adults and children. The patient with OSA will need a comprehensive cardiovascular, pulmonary, and airway evaluation. Opioid dosing should likely be decreased in the patient with OSA, especially children. Further evaluation is warranted if there is evidence of end organ damage, such as pulmonary HTN or right heart strain.

C. Endocrine.

1. Diabetes mellitus. Diabetes is a risk factor for CAD. The patient with autonomic nervous system dysfunction may have silent myocardial
ischemia. Alterations in autonomic regulation may also lead to gastroparesis and reflux. Endotracheal intubation may prove difficult in some of the diabetic patients secondary to arthritis of the temporomandibular joints and cervical spine (as a result of glycosylation of synovium). Home blood glucose measurements, hemoglobin A1c level, and question of recent symptomatic hyper- or hypoglycemia may further elucidate if the diabetes is well controlled.

2. Thyroid disease. It is important to discuss thyroid disorder as thyroid storm can lead to an intraoperative emergency. Thyroid storm occurs most commonly in patients with thyrotoxicosis secondary to Graves disease and as well in those with untreated disease.

D. Gastrointestinal.

1. Gastroesophageal reflux disease. Symptoms of reflux with or without hiatal hernia increase the risk of pulmonary aspiration and may alter the anesthetic plan; an awake intubation or a “rapid sequence” induction may be indicated. The patient should be asked specifically about chest pain/burning sensation, sour taste in the mouth after meals, frank regurgitation of food, or unexplained cough. It can also be important to delineate aggravating factors, such as provocation only with spicy foods versus with lying in the supine position.

2. Motion sickness or PONV history. A history of motion sickness and/or PONV increases the risk for PONV. Other factors associated with increased PONV risk include, but are not limited to, history of vertigo, female gender, nonsmoking status, gynecologic and laparoscopic procedures, strabismus surgery, and the need for large doses of perioperative or postoperative opioids. A different anesthetic technique, such as total intravenous anesthesia, may be warranted in the patient with multiple risk factors.

E. Musculoskeletal. A history of radiation to the head or neck may increase the risk of distorted airway anatomy and may alter intubation technique. The patient should also be questioned about joint pain for purposes of intraoperative positioning.

F. Obstetric/Gynecologic. Possibility of pregnancy and timing of last menses should be elicited in women of childbearing age as premedications and anesthetic agents may adversely affect uteroplacental blood flow, act as teratogens, or trigger spontaneous abortion.

G. Hematologic. A history of easy bruising, bleeding, or significantly heavy menses warrants further questioning and may require additional workup as coagulopathies necessitate intraoperative and neuraxial changes in management.

IV. THE PHYSICAL EXAMINATION

The physical examination should be thorough, but focused. Special attention is directed toward evaluation of the airway, heart, lungs, and neurologic status. A detailed assessment of the block site is warranted when a regional anesthetic technique is planned. At a minimum, the physical examination should include the following:

A. Vital Signs.

1. Blood pressure. Blood pressure measurement should be taken in both arms with any disparity noted (significant differences may imply disease of the thoracic aorta or its major branches). If hypovolemia is suspected, it is prudent to also measure postural vital signs.

2. Pulse. Resting heart rate should be noted for rhythm and rate.

3. Respiratory rate. Respirations should be observed for rate, depth, and pattern while at rest.

4. Oxygen saturation.

B. Height and Weight. Height and weight measurement are necessary for determining drug dosages, fluid requirements, adequate urine output, and ventilator settings. Ideal body weight should be calculated in the obese patient using the formula 50 + (2.3 × [height in inches over 60]) for men and 45.5 + (2.3 × [height in inches over 60]) for women.

C. Head and Neck. Details of a thorough head and neck examination are outlined in Chapter 14. During the basic preoperative examination, the anesthesiologist should evaluate the following:

1. Maximal mouth opening. Comment on predicted adequacy for intubation.

2. Tongue size.

3. Mallampati classification (see Chapter 14).

4. Thyromental distance. Thyromental distance is the distance between the tip of the chin and the thyroid notch. Approximately three finger-breadths distance is considered normal. Shorter or longer distances may be a sign of a difficult intubation.

5. Dentition. Evaluate for loose or chipped teeth, artificial crowns, dentures, and other dental appliances.

6. Facial hair. A large beard or mustache may interfere with achieving a good seal with mask ventilation and should be noted.

7. Cervical spine. Evaluate and document range of motion in flexion, extension, and rotation of the cervical spine.

8. Superficial neck. Comment on any tracheal deviation, cervical masses, and jugular venous distention. The presence of a carotid bruit is nonspecific but may suggest a need for further workup.

9. Neck circumference. A neck circumference measurement of 17″ for men and 16″ for women are associated with OSA.

D. Precordium. Auscultation of the heart may reveal murmurs, S3, S4, or a pericardial rub.

E. Lungs. Auscultate for wheezing, rhonchi, or rales, which should be correlated with observations regarding the ease of breathing and the use of accessory muscles of respiration.

F. Abdomen. Any evidence of abdominal distention, masses, or ascites should be noted as these may predispose the patient to regurgitation or ventilatory compromise.

G. Extremities. Evaluate for muscle wasting and weakness, distal perfusion, clubbing, cyanosis, edema, and the presence of any cutaneous infections (especially over sites of planned vascular cannulation or regional nerve block). Ecchymosis or unexplained injury, especially in children, women, and elderly patients, can be an indication of an abusive relationship.

H. Back. Note any deformity, bruising, or infection or any factors that could lead to difficulty in patient positioning or performance of neuraxial analgesia.

I. Neurologic Examination. Briefly document mental status, cranial nerve function, cognition, and peripheral sensorimotor function.

V. LABORATORY STUDIES

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