UNCOVERING PATIENT FACTORS THAT INCREASE THE RISK OF ANESTHESIA

This chapter provides information the anesthesiologist needs to know to ensure that his or her patient is asymptomatic from the standpoint of anesthetic risk. The management of patients found to be symptomatic is discussed in Chapter 27 . Ensuring that the patient is asymptomatic requires knowledge of the patient factors that increase the perioperative risk of anesthesia, because it is those factors that must be eliminated.

Major surgery usually represents a tremendous assault on the human organism. The body has an elaborate defense mechanism that alerts it to, and helps it escape from, trauma. The job of the anesthesiologist is not simply to put the patient to sleep and to wake him or her when surgery is over, but to maintain homeostasis during the assault of surgery and to provide pain relief to blunt the effects after the assault. To do this, the anesthesiologist

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Even when the stress of surgery is not felt consciously, it evokes a complex physiologic response. Much of this response is meant to allow the body to escape trauma. For example, blood flow is diverted from the kidney and liver to the heart and head, and blood pressure rises. Thus, the system most needed to be in a "good" state of health, the cardiovascular system, has first priority.^{[9] [18] [19] [20] [21] [22]} Elaborate and simple tests and history-taking processes have evolved to evaluate the cardiovascular system, especially in aged patients or patients with comorbid disease.^{[58] [59] [79] [80] [81]} We will evaluate the process of history-taking first.

The History

Unfortunately, illnesses in systems other than the cardiovascular have an effect on perioperative risk. The following is a list of relatively common conditions we ensure are not present before assuming that the patient is asymptomatic. ^{[24] [82] [83]} Chapter 24 and Chapter 27 discuss the increased risk posed by the problems discovered, and Chapter 27 describes optimization of the patient's physical condition, anticipation of potential problems, and possible therapies for the problems, and deals with managing drug regimens prior to procedures and surgery. The evaluation process that follows represents our initial screening procedure for disease. Although the process attempts to be relatively inclusive, it cannot cover all possible conditions that might be encountered when dealing with surgical patients.

First Areas of Concern and the Rule of Threes

The rule of threes indicates that three aspects of acute history, three aspects of chronic history, and three aspects of physical examination make a difference to perioperative outcome. The three aspects of acute history are:

1. Exercise tolerance
2. History of present illness and its treatments
3. When the patient last visited with her or his primary care physician

The three aspects of chronic history are:

1. Medications and causes for their use and allergies
2. Social history including drug, alcohol, and tobacco use and cessation
3. Family history and history of prior illnesses and operations

The three aspects of physical examination are:

1. Airway
2. Cardiovascular
3. Lung, plus those aspects specific to the patient's condition or planned procedure, such as a sensory nerve examination if a regional block is planned (more about physical examination later).

Included first in the history are general items, such as whether the patient has received recent medical care, has taken medication, or has allergies. (See Table 25-2 for an example of how such information is obtained from a patient when the institution does not use a computerized medical record.) Questions also are asked about prior exposure to anesthetics and subsequent problems:

When did you last have anesthesia?

Do you have any problems with anesthesia? Have any of your family members had any problems with anesthesia?

Do you have allergies?

What are you allergic to?

Have you had any blood tests in the last 6 months?

Have you had a chest x-ray in the last 2 months?

Have you had an electrocardiogram (ECG) in the last 2 months?

Has your stool been checked for blood or have you had a colonoscopy, etc., in the last year?

Have you been a patient in a hospital, an emergency department, or an outpatient surgery center in the last 2 years? If so, why? What part of the hospital (for example, critical care unit)? How long were you there?

Do you take any medications?

What medications do you take?

Do you take any medications not prescribed by your doctor, that you purchase through the internet or from a shelf at a drugstore, health food store, or grocery store?

Do you take any supplements or vitamins or minerals? (These can interact substantially with perioperative medications.)^{[84] [85] [86] [87]}

Also included in this category of questions are items about artificial devices (e.g., hearing aids, false eyes) and use of alcohol:

Do you wear contact lenses?

Do you currently use eye drops prescribed by a doctor?

When did you have an alcoholic drink?

Have you ever had a drinking problem?

Because patients tend to give socially acceptable answers on sensitive subjects (Trigg DJ et al, unpublished data),^[88] when probing in these types of areas a checklist or computer-aided history may be more valid than an interview. Sensitive subjects include risk factors for use of illegal drugs and for human immunodeficiency virus (HIV) infection. Nevertheless, the personal interview is essential for in-depth questioning.

Cardiovascular Disease

Most important is to determine the patient's cardiovascular reserve. ^{[58] [59] [65] [66] [67] [68] [69] [70] [79] [80] [81]} To do this, you can ask about the maximum amount the patient can walk or the greatest number of floors she or he can climb without the need to stop, or you can determine an ejection fraction from prior testing or the patient's record during stress testing. The ability to do 4 metabolic equivalents (METs) of exercise,^{[58] [59] [65]} the equivalent of walking 5 city blocks or climbing two flights of stairs at a reasonable rate without having to stop ( Table 25-4 ) correlates in multiple studies with better perioperative outcome^{[58] [59] [65] [66] [67] [68] [69] [70] [78] [79] [80] [81]}

We try to ensure that the patient does not have the following cardiovascular conditions: congestive heart failure, cardiomyopathies, ischemic heart disease (stable or unstable), valvular or subvalvular heart disease, hypertension (diastolic or systolic^[37] ), disturbances in cardiac rhythm, pericarditis, arteritis, or other manifestations of atherosclerosis.

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Questions should not be limited to the cardiovascular system. For example, to search for alcoholic cardiomyopathy, the following inquiries are made:

Have you had a drink in the last 72 hours?

Have you ever had a problem with drinking?

As mentioned previously, these two questions are the most sensitive and specific questions to ask when trying to determine the possibility of alcoholism. ^{[75] [76]}

Exercise tolerance should also be checked—for example, the patient's ability to walk up stairs, play sports, and perform chores (mowing lawns, making beds, vacuuming), without becoming short of breath.

Typical questions regarding the cardiovascular system include the following:

What is the most vigorous activity you've done in the last 3 weeks?

How far have you walked in the last week without stopping?

Can you walk a block without stopping? When did you last do so?

Can you walk 4 blocks without stopping? When did you last do so?

Have you ever awakened and felt short of breath?

Do you become short of breath after climbing a flight of stairs or after walking a short distance?

When did you last climb a flight of stairs?

Are you able to walk up stairs at the same rate as 5 years ago?

Can you climb 2 flights of stairs without stopping? When did you last do so?

Have you ever had a heart attack, or have you ever been treated for a possible heart attack?

Do you have heart problems such as skipped heart beats, angina, or chest pain?

Have you been told that you have a heart murmur or rheumatic fever?

Have you ever been told that you have mitral valve prolapse?

Have you ever had heart or lung surgery?

Do your ankles ever swell?

Are you ever short of breath? When?

Do you ever have chest pains, angina, chest heaviness, or chest tightness?

Do you ever have indigestion that does not occur after overeating?

Have you ever been told by your doctor to exercise or diet to control high blood pressure?

Have you ever been a patient in a critical care unit (cardiac care unit, intensive coronary care unit)?

Have you passed out or nearly passed out in the last year? Why?^[89]

Do you sleep with more than one pillow at night? (This question is useful only for men and women over age 60, as 50% of younger women sleep with two pillows [Trigg DJ et al, unpublished data]^[88] .)

Do you currently take water pills or diuretics?

Do you take medication for high blood pressure or medication to prevent high blood pressure?

Do you currently take potassium pills or powder?

Do you currently take anticoagulants or blood-thinning medicine?

Have you ever been told to take, or have you ever been given, antibiotics before routine dental work?

Sometimes these questions are asked in a different order, so that the patient is not startled or confused by them, as if they were a "pop quiz." To avoid surprising or confusing the patient, questions are asked in a "set." For instance, all questions related to medication are asked at the same time.

Respiratory and Airway Problems

Because airway problems cause substantial risk, the most important consideration regarding the respiratory system is securing the airway (also see Chapter 17 and Chapter 42 ). Therefore, evidence of airway obstruction and restriction

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The personal interview (no matter when performed) is usually quite efficient in revealing the condition of the airway, respiratory reserve, and the possible need for laboratory evaluation, such as pulmonary function testing with bronchodilators or blood gas analysis or both. Questioning the partner (if present) of those who snore or who have daytime somnolence can alert one to the probability of sleep apnea. While the presence of undiagnosed sleep apnea increases postoperative risk, we do not yet know appropriate interventions or benefit-risk strategies to gain more definitive diagnosis of such in a preoperative meeting. It is probable, although there are no data confirming this, that preoperative screening for sleep apnea in obese men over age 50 and in women over age 60 who snore and have daytime somnolence will prove to provide an outcome benefit.

The personal interview may also be the best time to educate the patient and family members about the time needed for cessation of smoking (and other use of tobacco products) in order to be beneficial (see Chapter 27 ).^{[54] [55] [56] [57]}

Questions that usually elicit information about the general condition of the mouth and airway and possible reactions to anesthesia include the following:

Do you wear dentures, a crown, a partial, or a bridge?

Are any of your teeth loose, cracked, chipped, or capped?

Have you ever had anesthesia?

Have you or any blood relative ever had any problems with anesthesia? (This question not only helps reveal possible airway problems but also elicits information about some rarer diseases, such as malignant hyperthermia, glucose-6-phosphate dehydrogenase [G6PD] deficiency, acute porphyria, allergies, sickle cell disease, neurologic disorders, and hiatus hernia. It usually also elicits concerns about postoperative nausea and vomiting and thus provides an opportunity to reassure the patient, to plan the choice of anesthetic, to ask female patients about their last menstrual period, and to use preanesthetic suggestion, for those physicians believing in the value of this practice.)

Can you open your mouth fully?

Do your joints ever click, pop, or hurt?

Have you ever been treated for a problem of the jaw joint (that is, a temporomandibular joint [TMJ] problem)?

Have you ever been hoarse for more than 1 month?

Do you snore, or do others say you snore? (This question proved to be the best predictor of difficult intubation when our computer-based health history was compared with outcome studies^[48] but was not very specific [four of five patients who answered yes to this question did not have a difficult intubation].)

Do you ever fall asleep in the daytime? Have you ever had a near-miss car accident because you almost fell asleep in the daytime? Was this not after a period of intentional sleep deprivation? How often?

Have you gained weight recently? (A 10% weight gain increases the number of apneic episodes by 30%.^[95] )

Have you ever had cancer?

Have you ever had, or been treated for, arthritis?

Do you have neck stiffness or problems moving your head?

Have you ever been told you had diphtheria? (Diphtheria can cause narrowing of the airway.)

The following questions search for lung disease:

Have you ever had pneumonia? When?

Have you ever undergone lung surgery?

Do you have shortness of breath, wheezing, chest pain, bronchitis, asthma, or emphysema?

Do you cough regularly or frequently?

Do you cough up mucus (sputum or phlegm)?

In the last 4 weeks, have you had a fever, chills, cold, or flu?

Do you smoke or have you ever smoked? When did you stop?

Do you use spit or chew tobacco?

Have you ever smoked half a pack or more of cigarettes a day on a regular basis?

Have you ever smoked a pipe or cigars on a regular basis?

Hepatic and Gastrointestinal Disease

Past and present hepatic disease increases the risk of certain surgical procedures (see Chapter 27 ), sometimes contributes to abnormal clotting and pharmacokinetics, and may present medicolegal concerns (e.g., in the case of postanesthetic jaundice). Hepatic disease also increases the risk of surgery for nonhepatic problems (see Chapter 27 ).

Gastrointestinal diseases may increase the potential for aspiration of gastric contents. For example, the gastroparesis of ulcer disease is often accompanied by solid food in the stomach, and inflammatory bowel disease may be accompanied by arthritis in the neck. Gastrointestinal disease also increases the potential for dehydration, electrolyte disturbances, and anemia. The presence of gastrointestinal or hepatic disease can give clues about possible endocrine, pulmonary, or cardiac disease (e.g., gastritis in the alcoholic patient could indicate alcoholic cardiomyopathy).

Questions that screen for gastrointestinal or hepatic disease include the following:

Have you ever been diagnosed as having a hiatus hernia?

Have you ever had hepatitis, yellow jaundice, liver disease, or malaria?

Have you ever had gallstones or gallbladder disease?

Are your stools ever bloody or black and tarry?

Have you seen bright red blood on your stool or on toilet tissue after wiping?

Have your bowel habits changed this year?

Do you often have diarrhea?

Have you ever vomited blood or material that looks like coffee grounds in the last 6 months?

Do you have frequent nausea or vomiting?

Have you lost weight this year without trying?

Has your appetite for food changed in the last year?

Are you eating the same foods you ate a year ago?

Have you had heartburn within the last month?

Are you now being treated, or have you been treated, for ulcer disease?

Are you currently taking antacids such as Tagamet (cimetidine), Zantac (ranitidine), Pepcid (famotidine), Prilosec (omeprazole), AcipHex (rabeprazole), or Axid (nizatidine)?

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Figure 25-2a Preoperative and Preprocedure Assessment Clinic (PPAC) Form 4: Patient preoperative and preprocedure history.

Figure 25-2b

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Bleeding Problems

Bleeding can occur because of a hereditary deficiency of clotting factors or because of abnormal platelet or vascular function caused by disease or drugs. The following questions search for such abnormalities:

Have you ever had a blood problem such as anemia or leukemia?

Have you ever had a problem with blood clotting?

Have you ever had a serious bleeding problem?

Have you received a blood transfusion since 1979?

Do you use any medications such as aspirin or vitamins such as vitamin E or supplements such as ginseng or garlic known to affect blood clotting? How much? How often? When did you last use such?

These questions are often asked in two ways, as patients seem to need time to recall such events. For example:

Has a family member or blood relative ever had a serious bleeding problem?

Have you ever had prolonged or unusual bleeding from cuts, nosebleeds, minor bruises, tooth extractions, or surgery?

Have you ever had excessive bleeding that required blood transfusion?

Renal Disease

Renal disease can contribute to bleeding because of a functional platelet deficit associated with renal impairment (see Chapter 27 ). In addition, renal insufficiency can increase risk because it produces anemia (prior to, or in the absence of, optimal erythropoietin therapy, which might be considered preoperatively to decrease transfusion need and to improve functional recovery (see Chapter 27 ), electrolyte disturbances, peripheral neuropathy, and abnormalities in drug metabolism and excretion. The following questions search for renal disease:

Have you ever had any kidney problem?

Have you ever had kidney failure, dialysis, or more than two kidney infections?

Have you ever had kidney stones?

Are you undergoing dialysis for kidney problems?

Have you had changes in bowel or bladder function in the last year?

Has your appetite for food changed in the last year? (Voluntary avoidance of foods having a high protein content is a subtle sign of renal disease.)

Endocrine Disturbances

Endocrine disturbances and the end-organ effects of diabetes or thyroid, parathyroid, pituitary, adrenal (and carcinoid) disease can increase perioperative risk substantially. For instance, morbidity and mortality increase 5- to 10-fold because of the nephropathy and autonomic insufficiency of diabetes (see Chapter 27 ). The following questions help ensure the patient does not have endocrine-related diseases:

Do you wake up at night to urinate? How often?

Have you ever been told that you have diabetes or sugar diabetes?

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Do you take, or have you taken steroids, cortisone, muscle-building supplements or steroids, or DHEAs or adrenocorticotropic hormone (ACTH) in the last year?

Do you perspire (sweat) much more than others or a great deal every now and then?

How often do you have headaches?

Does your face flush or get red every now and then, even when you are not exercising?

The last three questions attempt to rule out the hazardous perioperative situation of undiscovered pheochromocytoma or carcinoid syndromes. Both conditions can now be well managed if known about in advance (see Chapter 27 ). Both, however, incur a mortality rate as high as 10% if undiscovered prior to operation.

The following questions search for symptoms of thyroid and parathyroid disease:

Have you ever taken medicine (e.g., Synthroid [levothyroxine]) or had radioactive iodine (¹³¹ I) for thyroid disease?

Do you consistently like the room warmer or colder than your spouse does?

Do you have muscle cramps or spasma in your legs more than three times a year?

Neurologic Disease

Physical examination can add significantly to one's impressions and can reduce the necessity for some questions, particularly regarding neurologic disease. Nevertheless, to exclude neurologic disease, the following questions are usually asked:

Have you ever had a seizure, convulsion, fit, stroke, or paralysis?

Have you ever been diagnosed as having a tremor?

Have you ever had migraine headaches?

Have you ever had nerve injury, multiple sclerosis, or any other disorder of the nervous system?

Have you ever had numbness, tingling, or "pins-and-needles" in your arm or leg that has lasted more than 2 hours?

Have you taken antidepressant, sedative, tranquilizing, or antiseizure medications in the last year? Do you take SAM-e (adenosyl methionine) or St. John's Wort because of feeling blue? (I might add, if the patient is a woman over age 45 years, Do you take any medications for hot flashes or for peri- or postmenopausal symptoms?^{[84] [85] [86] [87]} ).

Musculoskeletal Disease

Because arthritis affects the ease of securing the airway, I usually ask about potential musculoskeletal system disease during the search for airway and lung disease. A brief review could include the following questions:

Have you ever had low back pain?

Have you been working at your usual job or doing your normal activities in the last week?

Have you taken pain pills or had pain shots in the last 6 months?

Sensitive Areas of Concern

One area not yet discussed concerns more difficult-to-manage subjects, such as the possibility of pregnancy, and the possibility of pregnancy in a minor, asymptomatic hemoglobinopathies when intense counseling and consultation service are not available, illicit drug use, and the potential for acquired immunodeficiency syndrome (AIDS). I believe that such matters should be handled in concert with hospital or facility policy.^[96] However, because this kind of information can affect perioperative risk and plans, my usual procedure is to search for clues in the history. If one has taken the time to gain the patient's confidence so that the patient understands that these questions are being asked in order to provide better care, success is possible. If one tries to approach these sensitive areas in the 5 to 15 minutes usually allotted, the process is awkward at best and usually does not succeed. In fact, patients seem to answer these questions more reliably on a checklist paper-and-pencil form or on a computer-based health history (Trigg DJ et al, unpublished data).^{[71] [88]}

Under optimal conditions, the questions that can be asked include the following:

Within the last 2 years, have you taken nonprescription drugs, such as cocaine, crack, heroin, or LSD?

Have you been exposed to the body fluids (blood, semen, urine, or saliva) of anyone likely to have the AIDS virus?

Are you in any of the groups at high risk for AIDS (homosexuals, bisexuals, hemophiliacs, and those who have had sex with a prostitute within the last 18 years)?

Would you like to undergo a test to find out whether you have been exposed to the AIDS virus?

From an institutional point of view, in the future AIDS testing will be an especially important consideration.