Preoperative medical evaluation of the adult healthy patient

See "Evaluation of cardiac risk prior to noncardiac surgery" and "Perioperative medication management" and "Overview of the principles of medical consultation and perioperative medicine"

Official reprint from UpToDate www.uptodate.com ©2016 UpToDate

Author

Gerald W Smetana, MD

Section Editors

Andrew D Auerbach, MD, MPHNatalie F Holt, MD, MPH

Deputy Editor

Lee Park, MD, MPH

Preoperative medical evaluation of the adult healthy patient

All topics are updated as new evidence becomes available and our peer review process is complete

Literature review current through: Jun 2016 | This topic last updated: Jul 27, 2016.

INTRODUCTION — Clinicians are often asked to evaluate a patient prior to surgery The medical

consultant may be seeing the patient at the request of the surgeon or may be the primary care clinician

assessing the patient prior to consideration of a surgical referral The goal of the evaluation of the

healthy patient is to detect unrecognized disease and risk factors that may increase the risk of surgery

above baseline and to propose strategies to reduce this risk

The evaluation of healthy patients prior to surgery is reviewed here Preoperative assessments for

specific systems issues and surgical procedures are discussed separately (See "Evaluation of cardiac

risk prior to noncardiac surgery" and "Perioperative medication management" and "Overview of the

principles of medical consultation and perioperative medicine" and "Evaluation of preoperative

pulmonary risk".)

CLINICAL EVALUATION — In general, the overall risk of surgery is extremely low in healthy individuals.

Therefore, the ability to stratify risk by commonly performed evaluations is limited

Screening questionnaire — Screening questions appear on many standard institutional preoperative

evaluation forms One validated screening instrument, derived from 100 patients, comprises 17

questions that allowed nurses to identify those patients who would benefit from a formal preoperative

evaluation by an anesthesiologist (table 1) [1] The questions chosen for this questionnaire were devised

to detect preexisting conditions shown to be associated with perioperative adverse events

Age — A number of commonly employed and validated indices consider age as a minor component of

preoperative coronary risk (See "Evaluation of cardiac risk prior to noncardiac surgery".)

Some studies have found a small increased risk of surgery associated with advancing age [2,3] In a

review of 50,000 older adult patients, for example, the risk of mortality with elective surgery increased

from 1.3 percent for those under 60 years of age to 11.3 percent in the 80- to 89-year-old age group [3

Among 1.2 million Medicare patients undergoing elective surgery, mortality risk increased linearly with

age for most surgical procedures [4] Operative mortality for patients 80 years and older was more than

twice that of patients 65 to 69 years old However, age was not a significant predictor of cardiac

complications after multivariable analysis in the cohort of patients used to derive a revised cardiac risk

index [5

In addition to the minor influence of age on perioperative cardiac risk, there is more robust literature

supporting age as an independent risk factor for postoperative pulmonary complications Age was one of

the most important patient-related predictors of pulmonary risk, even after adjusting for common

age-related comorbidities, in a systematic review [6] (See "Evaluation of preoperative pulmonary risk".)

By contrast, some studies have found little relation between age and mortality rates due to surgery One

study reported the outcomes of surgery in 795 patients over 90 years of age [7] No patients were Class

I as classified by the American Society of Anesthesiologists (ASA) physical status classification (table 2);

80 percent were ASA Class III or greater Despite higher perioperative mortality rates in older adults,

®

®

survival at two years was no different than the actuarial survival in matched patients not undergoing

surgery [7] A larger study of 4315 patients also found a higher perioperative complication and mortality

rate in older individuals, but the mortality rate was low [8] Among 31 patients age 100 years and older

undergoing surgery requiring anesthesia, perioperative and one-year mortality rates were similar to

matched peers from the general population [9

After adjusting for comorbidities more common with age, the impact of age on perioperative outcomes is

modest Much of the risk associated with age is due to increasing numbers of comorbidities, which may

include cognitive impairment, functional impairment, malnutrition, and frailty [10] Geriatric patients may

benefit from preoperative assessments in those areas, but age should not be used as the sole criterion

to guide preoperative testing or to withhold a surgical procedure [11] A risk calculator developed by the

American College of Surgeons National Surgery Quality Improvement Program may be helpful in

assessing preoperative risk in an older patient

Exercise capacity — All patients should be asked about their exercise capacity as part of the

preoperative evaluation Exercise capacity is an important determinant of overall perioperative risk;

patients with good exercise tolerance generally have low risk (See "Evaluation of cardiac risk prior to

noncardiac surgery", section on 'Initial preoperative evaluation'.)

The American College of Cardiology/American Heart Association guideline on preoperative cardiac

evaluation recommends no testing for patients with good exercise capacity (at least 4 metabolic

equivalents [METs]) regardless of the risk of the planned procedure (algorithm 1) [12] Patients’ ability to

expend ≥4 METs can be assessed by estimates from activities of daily living; activities that expend ≥4

METS include the ability to climb up a flight of stairs, walk up a hill, walk at ground level at 4 miles per

hour, or perform heavy work around the house [12]

Alternatively, more formal activity scales can be used An observational study of 87 patients found that,

compared with the Duke Activity Status Index, subjective assessment by clinicians generally

underestimated exercise capacity [13]

In general, healthy patients who can perform these activities as part of their daily routine have a low risk

for major postoperative complications This was illustrated in a study of 600 consecutive patients

undergoing major surgery [14] The investigators defined poor exercise capacity as the inability to either

walk four blocks or climb two flights of stairs Patients reporting poor exercise capacity had twice as

many serious postoperative complications as those who reported good exercise capacity (20 versus 10

percent, respectively) There was also a difference in cardiovascular complications (10 versus 5

percent), but not in total pulmonary complications (9 versus 6 percent)

The importance of functional capacity was confirmed objectively in another report of 847 patients

undergoing elective abdominal surgery [15] In this study, poor exercise capacity, confirmed by

cardiopulmonary exercise testing, was a stronger predictor of all-cause mortality than any of the

conventional cardiac risk factors of the Revised Cardiac Risk Index

Medication use — Clinicians should obtain a history of medication use for all patients before surgery

and should specifically inquire about over-the-counter, complementary, and alternative medications

Aspirin, ibuprofen, and other nonsteroidal antiinflammatory drugs (NSAIDs) are associated with an

increased risk of perioperative bleeding Specific inquiry about use of complementary and alternative

medications should also be part of the preoperative assessment A detailed discussion of perioperative

medication management is presented separately (See "Perioperative medication management".)

Obesity — Contrary to popular belief, in noncardiac surgery, obesity is not a risk factor for most major

adverse postoperative outcomes, with the exception of pulmonary embolism None of the published and

widely disseminated cardiac risk indices for noncardiac surgery include obesity as a risk factor for

postoperative cardiac complications

Representative studies related to postoperative mortality in noncardiac surgery include:

Other studies relating to complications in noncardiac surgery found that obesity increases rates for

wound infections but has no effect on other postoperative complications except for postoperative deep

venous thrombosis and pulmonary embolism [6,18-22] (See "Prevention of venous thromboembolic

disease in surgical patients".)

However, in cardiac surgery, some studies have shown higher complication rates for obese patients,

including increased hospital stay [23], wound infections [23,24], prolonged mechanical ventilation [24],

and atrial arrhythmias [24,25]

Obstructive sleep apnea — Given the increased risks of perioperative morbidity and the potential for

altered anesthetic management, it is reasonable to screen patients for obstructive sleep apnea (OSA)

before surgery with one of several validated screening instruments OSA increases the risk for

postoperative medical complications including hypoxemia, respiratory failure, unplanned reintubation,

and intensive care unit (ICU) transfer [26] Most patients with OSA are undiagnosed The prevalence of

previously undetected OSA is particularly high in patients preparing for bariatric surgery A detailed

discussion of the perioperative risks and the role of screening for OSA is presented elsewhere (See

"Surgical risk and the preoperative evaluation and management of adults with obstructive sleep apnea".)

Alcohol misuse — Patients who misuse alcohol on a regular basis have an increased risk for

postoperative complications [27] Screening for alcohol misuse before surgery will identify a subset of

patients at increased risk for postoperative medical complications While the benefit of directed alcohol

cessation programs before surgery is not well-established in the literature, there is little apparent risk to

such a strategy The preoperative period also serves as an opportunity to identify patients who misuse

alcohol and are candidates for intervention as part of primary care follow-up after surgery Pending

further study, it is reasonable to screen all patients for alcohol misuse before elective major surgery

In a study of 9176 male US veterans, a screening questionnaire for alcohol misuse administered at any

time within one year before surgery accurately stratified risk of postoperative complications [28] There

was a continuous relationship between postoperative complications and risk scores using the Alcohol

Use Disorders Identification Test-Consumption (AUDIT-C) questionnaire (table 3) Surgical site

infections, other infections, and cardiopulmonary complications each increased across the strata of risk

groups based on alcohol use patterns A similarly conducted trial of the AUDIT-C questionnaire before

total joint arthroplasty revealed comparable results [29] Patients with high AUDIT-C scores (9 to 12 of

12 possible points) within the year before surgery also have longer lengths of stay, more ICU days, and

higher unplanned reoperation rates [30]

Most trials of alcohol cessation interventions have been conducted in the nonoperative setting; a small

study in patients undergoing colorectal surgery reported a beneficial effect of alcohol screening on

postoperative complications [31] The optimal period of cessation is unknown but at least four weeks of

abstinence are required to reverse selected physiologic abnormalities [27]

In a matched case control study of 1962 patients undergoing noncardiac surgery, obesity was notassociated with increased mortality (1.1 percent in obese patients versus 1.2 percent in controls)[16]

●

Illicit drug use — In order to provide appropriate perioperative care, it is helpful to ask patients about

illicit drug use [32] Patients with chronic opioid use may have developed tolerance and require higher

than usual doses in the intraoperative and postoperative period Patients who abuse opioids,

barbiturates, or amphetamines are at risk for drug withdrawal in the postoperative period (See

"Substance use disorder: Principles for recognition and assessment in general medical care".)

Smoking — Evaluating tobacco use and offering strategies to quit smoking may reduce postoperative

morbidity and mortality, as current smokers have an increased risk for postoperative complications

Smoking cessation prior to surgery may reduce the risk of postoperative complications, and longer

periods of smoking cessation may be even more effective Smokers should be encouraged to quit

immediately preoperatively (See "Strategies to reduce postoperative pulmonary complications in adults",

section on 'Smoking cessation' and "Overview of smoking cessation management in adults" and

"Behavioral approaches to smoking cessation".)

In cohort and case-control studies, preoperative smoking has been associated with an increased risk of

postoperative complications, including general morbidity (relative risk [RR] 1.52, 95% CI 1.33-1.74),

wound complications (RR 2.15, 95% CI 1.87-2.49), general infections (RR 1.54, 95% CI 1.32-1.79),

pulmonary complications (RR 1.73, 95% CI 1.35-2.23), neurological complications (RR 1.38, 95% CI

1.01-1.88), and admission to an ICU (RR 1.60, 95% CI 1.14-2.25) [33] (See "Evaluation of preoperative

pulmonary risk", section on 'Smoking'.)

Personal or family history of anesthetic complications — Malignant hyperthermia is a rare

complication of anesthetic administration that is inherited in an autosomal dominant fashion Due to the

morbidity and potential mortality associated with this condition, the preoperative history should include

questioning about either a personal or family history of complications from anesthesia (See

"Susceptibility to malignant hyperthermia: Evaluation and management" and "Malignant hyperthermia:

Clinical diagnosis and management of acute crisis".)

LABORATORY EVALUATION — Several review articles in perioperative consultation and most local

institutional policies support a selective approach to preoperative testing [34-40] A practice advisory

from the American Society of Anesthesiologists (ASA) and a safety guideline from the Association of

Anaesthetists of Great Britain and Ireland recommend against routine preoperative laboratory testing in

the absence of clinical indications [40,41]

Rationale for selective testing — The prevalence of unrecognized disease that influences surgical risk

is low in healthy individuals Nevertheless, clinicians often perform laboratory tests in this group of

patients out of habit and medicolegal concern, with little benefit and a high incidence of false-positive

results Representative studies that have addressed this issue include:

In a trial of 1061 ambulatory surgical patients randomly assigned to preoperative testing or notesting, there was no difference in perioperative adverse events or events within 30 days ofambulatory surgery [42] Patients assigned to testing could receive a complete blood count,electrolytes, blood glucose, creatinine, electrocardiogram (ECG), and/or chest radiograph, based

on the Ontario Preoperative Testing Grid

●

Medical consultants commonly see patients before planned cataract surgery In many institutions,guidelines still require routine laboratory testing despite compelling evidence showing no benefit ofsuch testing A systematic review of three randomized trials of testing versus no testing in a total of21,531 cataract surgeries found that adverse events did not differ between the two groups [43]

Institutions may safely eliminate a requirement for routine laboratory tests before cataract surgery

●

In a retrospective study of 2000 patients undergoing elective surgery, 60 percent of routinelyordered tests would not have been performed if testing had only been done for recognizableindications; only 0.22 percent of these revealed abnormalities that might influence perioperative

●

Predictive value — There are several arguments for avoiding routine preoperative tests Normal test

values are usually arbitrarily defined as those occurring within two standard deviations from the mean,

thereby ensuring that 5 percent of healthy individuals who have a single screening test will have an

abnormal result As more tests are ordered, the likelihood of a false-positive test increases; a screening

panel containing 20 independent tests in a patient with no disease will yield at least one abnormal result

64 percent of the time (table 4)

Thus, the predictive value of abnormal test results is low in healthy patients with a low prevalence of

disease (table 5) Aside from possibly causing patient alarm, the additional testing prompted by

false-positive screening tests leads to unnecessary costs, risks, and a potential delay of surgery In addition,

clinicians often fail to act upon abnormal test results from routine preoperative testing, thereby creating

an additional medicolegal risk

A review of studies of routine preoperative testing pooled data and estimated the incidence of

abnormalities that affect patient management and the positive and negative likelihood ratios for a

postoperative complication (table 6) [35] For nearly all potential laboratory studies, a normal test did not

substantially reduce the likelihood of a postoperative complication (the negative likelihood ratio

approached 1.0) Positive likelihood ratios were modest, and they exceeded 3.0 for only three tests

(hemoglobin, renal function, and electrolytes); however, clinical evaluation can predict most patients with

an abnormal result This was illustrated by the low incidence of a change in preoperative management

based on an abnormal test result (0 to 3 percent)

Timing of laboratory testing — When laboratory tests are felt to be necessary, it is reasonable to use

test results that were performed and were normal within the past four months, unless there has been an

interim change in clinical status The validity of this approach was illustrated in an observational study

which investigated the usefulness of 7549 preoperative tests performed at the time of admission in 1109

patients undergoing elective surgery [37] In 47 percent of cases, the same tests had been performed

within the previous year When repeated at admission:

management [34] Further chart review determined that these abnormalities were not acted upon,nor did they have adverse surgical consequences

One report found that only 10 routine laboratory test results in 3782 patients required treatment;

just one of these required pharmacologic treatment [44] In a prospective study of 1363 patients forwhom laboratory testing was performed at the discretion of the perioperative clinician, only anabnormal ECG predicted postoperative complications Abnormalities in commonly performed bloodtest and chest radiography had no predictive value [45]

●

Investigators performed a retrospective review of 73,596 patients undergoing elective hernia repairusing the National Surgical Quality Improvement Program (NSQIP) database [46] Preoperativetests were performed in 63.8 percent of patients; 61.6 percent of these patients had at least oneabnormal test result Among patients with no accepted medical indication for testing, 54 percentnonetheless received at least one test After adjustment for demographics, comorbidities, andprocedure characteristics, neither preoperative testing nor the finding of an abnormal test resultwere associated with adverse postoperative outcomes

●

Of 3096 previously normal tests (performed a median of two months prior to admission), only 13(0.4 percent) values were outside a range considered acceptable for surgery, and most of thesepatients had a change in clinical history that predicted the abnormality

●

Of 461 previously abnormal tests, when repeated at admission, only 78 (17 percent) remainedoutside a range considered acceptable for surgery, suggesting that it is useful to repeat abnormaltests in the immediate preoperative period

●

Laboratory studies — While preoperative laboratory testing is not routinely indicated, selective testing

is appropriate in specific circumstances, including patients with known underlying diseases or risk factors

that would affect operative management or increase risk, and specific high-risk surgical procedures [38]

Specific laboratory studies commonly ordered for preoperative evaluation include a complete blood

count, electrolytes, renal function, blood glucose, liver function studies, hemostasis evaluation, and

urinalysis These tests are discussed below with indications for their use in specific populations and

surgeries

Complete blood count

Renal function — It is appropriate to obtain a serum creatinine concentration in patients over the

age of 50 undergoing intermediate- or high-risk surgery, although there is no clear consensus on this

point It should also be ordered when hypotension is likely, or when nephrotoxic medications will be

used

Mild to moderate renal impairment is usually asymptomatic; the prevalence of an elevated creatinine

among asymptomatic patients with no history of renal disease is only 0.2 percent [34,50] However, the

prevalence increases with age In one study, for example, the prevalence among unselected patients

aged 46 to 60 was 9.8 percent [51]

In the revised cardiac risk index, a serum creatinine >2.0 mg/dL (177 micromol/L) was one of six

independent factors that predicted postoperative cardiac complications [5] Renal insufficiency is also an

Hemoglobin/hematocrit – A baseline hemoglobin measurement is suggested for all patients 65

years of age or older who are undergoing major surgery and for younger patients undergoing majorsurgery that is expected to result in significant blood loss By contrast, hemoglobin measurement isnot necessary for those undergoing minor surgery unless the history suggests anemia

●

Anemia is present in approximately 1 percent of asymptomatic patients; surgically significantanemia has an even lower prevalence [34] However, anemia is common following major surgeryand the preoperative hemoglobin level predicts postoperative mortality As an example, a largeobservational study of older veterans (n = 310,311, age ≥65 years) found an increase in 30-daypostoperative mortality for patients with mildly abnormal preoperative hematocrits undergoing majornoncardiac surgery, even in the absence of significant blood loss [47] Adjusted mortality increased

by 1.6 percent (95% CI 1.1 to 2.2 percent) for every one percentage point increase or decreasefrom a normal hematocrit, defined as 39.0 to 53.9 percent

The data cannot distinguish whether an abnormal hematocrit serves as a marker for coexistentdisease that increases mortality risk, or whether the anemia itself increases physiologic stressesand therefore complication rates

The observation that outcomes do not differ for patients undergoing hip surgery who were randomlyassigned to either liberal or restrictive transfusion policies suggests that anemia is a marker for risk,rather than the cause of morbidity [48] It remains unclear if the increased risk due to anemia ismodifiable by interventions aimed at correcting the hematocrit

White blood cell count and platelets – The frequency of significant unsuspected white blood cell

or platelet abnormalities is low [34] It is reasonable to measure platelet count when neuraxialanesthesia (spinal or epidural) is planned Unlike the hemoglobin concentration, however, there islittle rationale to support baseline testing of either Nevertheless, obtaining a complete blood count,including white count and platelet measurement, can be recommended if the cost is not

substantially greater than the cost of a hemoglobin concentration alone There may be some costsincurred due to follow-up of false-positive results; however, with respect to platelet counts, thesecosts do not appear to be substantial [49]

●

independent risk factor for postoperative pulmonary complications [6] and a major predictor of

postoperative mortality [52] Renal insufficiency necessitates dosage adjustment of some medications

that may be used perioperatively (eg, muscle relaxants)

Electrolytes — Routine electrolyte determinations are NOT recommended unless the patient has a

history that increases the likelihood of an abnormality The frequency of unexpected electrolyte

abnormalities is low (0.6 percent in one report) [34] While preoperative hypernatremia is associated with

an increase in perioperative 30-day morbidity and mortality [53], the relationship between most

electrolyte derangements and operative morbidity is not clear Furthermore, clinicians can predict most

abnormalities based on history (for example, current use of a diuretic, angiotensin-converting enzyme

[ACE] inhibitor, or angiotensin receptor blocker [ARB], or known chronic kidney disease)

Blood glucose — Routine measurement of blood glucose is NOT recommended for healthy

patients Unexpected abnormal blood glucose results do not often influence perioperative management

As an example, one study evaluated the benefit of routine laboratory testing in 1010 presumably healthy

patients undergoing cholecystectomy [50] Eight patients had unexpected elevations in preoperative

serum glucose; only one of these patients developed significant postoperative hyperglycemia, and this

was not recognized until after total parenteral nutrition was started No patient in this study benefited

from routine preoperative measurement of serum glucose

Also, the frequency of glucose abnormalities increases with age; almost 25 percent of patients over age

60 had an abnormal value in one report [51] Most controlled studies have not found a relationship

between operative risk and diabetes [2,51], except in patients undergoing vascular surgery or coronary

artery bypass grafting [54,55] While the revised cardiac risk index identified diabetes as a risk factor for

postoperative cardiac complications, only patients with insulin-treated diabetes were at risk [5] There is

no evidence that asymptomatic hyperglycemia, in a patient not previously known to have diabetes,

increases surgical risk The rate of asymptomatic hyperglycemia in unselected surgical patients is low; in

one report, the incidence was only 1.2 percent [56]

Liver function tests — Routine liver enzyme testing is NOT recommended Unexpected liver

enzyme abnormalities are uncommon, occurring in only 0.3 percent of patients in one series [44] In a

pooled data analysis, only 0.1 percent of all routine preoperative liver function tests changed

preoperative management (table 6) [35] In a study of the NSQIP database, among 25,149 patient with

no comorbidities, the relative risk for major postoperative complications among patients who received

preoperative liver function tests, when compared with those with no testing, approached one (RR 0.94,

95% CI 0.42-2.08) [46]

Severe liver function test abnormalities among patients with cirrhosis or acute liver disease are

associated with increased surgical morbidity and mortality, but no data suggest that mild abnormalities

among patients with no known liver disease have a similar impact [57] Clinically significant liver disease

would most likely be suspected on the basis of the history and physical examination

Tests of hemostasis — Routine preoperative tests of hemostasis are NOT recommended If the

history, physical examination, and family history do not suggest the presence of a bleeding disorder, no

additional laboratory testing is required If the evaluation suggests the presence of a bleeding disorder,

appropriate screening tests should be performed, including prothrombin time (PT), activated partial

thromboplastin time (aPTT), and platelet count [58] For some bleeding disorders (eg, inherited platelet

disorder, hemophilia carrier), additional tests may be required to establish a diagnosis and identify the

degree of abnormality [58,59] (See "Preoperative assessment of hemostasis".)

Unexpected significant abnormalities of the PT or PTT are uncommon [34,49] Inherited coagulation

defects are quite rare For example, the incidence of hemophilia A and B among men is 1:5000 and

1:30,000, respectively [60] Nearly all of these cases would be evident based on clinical presentation

prior to the preoperative medical evaluation In addition, the relationship between an abnormal result and

the risk of perioperative hemorrhage is not well-defined but appears to be quite low, particularly in those

who are thought to have a low risk of hemorrhage on the basis of history and physical examination

[61,62] Even among neurosurgical patients, for whom a small amount of unanticipated bleeding could

cause substantial morbidity, the medical history is the most useful screening test for bleeding diathesis

In a study of 11,804 patients undergoing spinal or intracranial surgery, a medical history that suggested

risk for bleeding complications was substantially more sensitive that PT or PTT values in predicting need

for transfusion, unplanned reoperation, and mortality [63]

In a pooled data analysis, an abnormal PT had a positive likelihood ratio of 0 for predicting a

postoperative complication and a negative likelihood ratio of 1.01 (table 6); in no case did the finding of

an abnormal PT change patient management or modify the likelihood of a complication [35] Similarly,

the bleeding time is not useful in assessing the risk of perioperative hemorrhage [64,65]

Urinalysis — Routine urinalysis is NOT recommended preoperatively for most surgical procedures.

The theoretical reason to obtain a preoperative urinalysis is detection of unsuspected urinary tract

infection Urinary tract infections have the potential to cause bacteremia and postsurgical wound

infections, particularly with prosthetic surgery [66] Patients with positive urinalysis and urine culture are

generally treated with antibiotics and proceed with surgery without delay [67] However, it is unclear

whether a positive preoperative urinalysis and culture with subsequent antibiotic treatment prevent

postsurgical infection One study found no difference in wound infection between patients with normal

and abnormal urinalysis [68] Another study found that patients with asymptomatic urinary tract infection

detected by urinalysis had an increased risk of wound infection postoperatively, despite treatment [69]

A cost-effectiveness analysis estimated that 4.58 wound infections in nonprosthetic knee operations may

be prevented annually by the use of routine urinalysis, at a cost of $1,500,000 per wound infection

prevented [70]

Asymptomatic renal disease can be detected by measurement of serum creatinine in selected patients

(See 'Renal function' above.)

Pregnancy testing — The knowledge that a woman is pregnant substantially changes perioperative

management We suggest pregnancy testing in all reproductive-age women prior to surgery The patient

may elect to cancel elective surgery, or may decide in collaboration with her clinicians to undertake a

different, lower-risk surgery than originally planned In addition, anesthetic technique differs for pregnant

women, and there may be risks to the fetus if a pregnancy goes undetected before surgery and

anesthesia

Guidelines in the United Kingdom recommend always asking about the possibility of pregnancy before

surgery and, if pregnancy is possible after history-taking, offering a pregnancy test [71,72] The ASA

recommends that clinicians offer pregnancy testing for women of childbearing age if the results would

alter management [40] While these guidelines provide some discretion in deciding which women to test,

it is often not possible to reliably exclude pregnancy based on medical history-taking alone [73] Many

institutions require pregnancy testing for all reproductive age women before surgery There is low risk to

this approach; false-positives are rare, testing is inexpensive, and the results return rapidly (See

"Clinical manifestations and diagnosis of early pregnancy", section on 'Detection of hCG'.)

ELECTROCARDIOGRAM — We suggest NOT ordering an electrocardiogram (ECG) for asymptomatic

patients undergoing low-risk surgical procedures ECGs have a low likelihood of changing perioperative

management in the absence of known cardiac disease The prevalence of abnormal ECGs increases

with age [74] Important ECG abnormalities in patients younger than 45 years with no known cardiac

disease are very infrequent

The 2014 American College of Cardiology/American Heart Association (ACC/AHA) Guidelines on

Perioperative Cardiovascular Evaluation state that ECG is not useful in asymptomatic patients

undergoing low-risk procedures [75] Similarly, the European Society of Cardiology 2014 preoperative

guidelines do not recommend ECG in patients without risk factors [76]

The 2014 ACC/AHA guidelines recommend a preoperative resting 12-lead ECG for patients with known

coronary artery disease, significant arrhythmia, peripheral arterial disease, cerebrovascular disease or

other significant structural heart disease, except for those undergoing low-risk surgery (risk of major

adverse cardiac event <1 percent) [75] A preoperative resting ECG can also be considered for

asymptomatic patients undergoing surgery with elevated risk (risk of major adverse cardiac event ≥1

percent) Preoperative evaluation of patients with known cardiovascular disease or risk factors is

discussed in detail elsewhere (See "Evaluation of cardiac risk prior to noncardiac surgery".)

It is uncertain whether the preoperative approach to obese patients should differ from that of the general

population in regard to ECGs This is discussed separately (See "Preanesthesia medical evaluation of

the obese patient", section on 'Screening for comorbidities'.)

CHEST RADIOGRAPH — While routine preoperative chest radiographs are not indicated, we agree

with the American College of Physicians (ACP) recommendation for chest radiographs in patients with

cardiopulmonary disease and those older than 50 years of age who are undergoing abdominal aortic

aneurysm surgery or upper abdominal/thoracic surgery [6] Posteroanterior and lateral chest radiograph

is also suggested by the American Heart Association for patients with severe obesity (BMI ≥40 kg/m2)

[77] In these patients, the chest radiograph may indicate undiagnosed heart failure, cardiac chamber

enlargement, or abnormal pulmonary vascularity suggestive of pulmonary hypertension, warranting

further cardiovascular investigation The relationship between findings on chest radiograph and

perioperative morbidity are not well-defined in these populations, however, and studies are not available

that indicate that preoperative radiography changes perioperative outcomes Thus, we do not suggest

routine chest radiographs in severely obese patients, unless additional criteria such as poor exercise

tolerance and risk factors for coronary artery disease are present

Preoperative chest radiographs add little to the clinical evaluation in identifying patients at risk for

perioperative complications [39] Abnormal findings on chest radiograph occur frequently and are more

prevalent in older patients [78] Several systematic reviews and independent advisory organizations in

the United States and Europe recommend against routine chest radiography in healthy patients [79-82]

There is little evidence to support the use of a preoperative chest radiograph regardless of age unless

there is known or suspected cardiopulmonary disease from the history or physical examination In a

meta-analysis of 21 studies of routine chest radiography, among a total of 14,390 routine chest

radiographs, there were 1444 abnormal studies [83] Only 140 abnormal findings were unexpected, and

only 14 (0.1 percent) of all routine chest radiographs influenced management

One study screened 905 surgical admissions for the presence of clinical factors that were thought to be

risk factors for an abnormal preoperative chest radiograph [84] The risk factors included age over 60

years or clinical findings consistent with cardiac or pulmonary disease No risk factors were evident in

368 patients; of these, only one (0.3 percent) had an abnormal chest radiograph, which did not affect the

surgery On the other hand, 504 patients had identifiable risk factors; of these, 114 (22 percent) had

significant abnormalities on preoperative chest radiograph

PULMONARY FUNCTION TESTS — Routine pulmonary function tests are NOT indicated for healthy

patients prior to surgery (See "Evaluation of preoperative pulmonary risk".)

These tests generally should be reserved for patients who have dyspnea that remains unexplained after

careful clinical evaluation Clinical findings are more predictive of the risk of postoperative pulmonary

complications than are spirometric results [85] These findings include decreased breath sounds,

prolonged expiratory phase, rales, rhonchi, or wheezes

INFORMATION FOR PATIENTS — UpToDate offers two types of patient education materials, “The

Basics” and “Beyond the Basics.” The Basics patient education pieces are written in plain language, at

the 5 to 6 grade reading level, and they answer the four or five key questions a patient might have

about a given condition These articles are best for patients who want a general overview and who prefer

short, easy-to-read materials Beyond the Basics patient education pieces are longer, more

sophisticated, and more detailed These articles are written at the 10 to 12 grade reading level and

are best for patients who want in-depth information and are comfortable with some medical jargon

Here are the patient education articles that are relevant to this topic We encourage you to print or e-mail

these topics to your patients (You can also locate patient education articles on a variety of subjects by

searching on “patient info” and the keyword(s) of interest.)

SUMMARY AND RECOMMENDATIONS — The overall risk of surgery is low in healthy individuals.

Preoperative tests usually lead to false-positive results, unnecessary costs, and a potential delay of

surgery Preoperative tests should not be performed unless there is a clear clinical indication

postoperative outcomes in patients undergoing noncardiac surgery, with the exception ofthromboembolic events Clinicians should also inquire about personal or family history ofcomplications from anesthesia and screen for symptoms of obstructive sleep apnea (OSA) (See'Clinical evaluation' above.)

●

Routine preoperative laboratory tests have not been shown to improve patient outcomes amonghealthy patients undergoing surgery In addition, routine testing in healthy patients has poorpredictive value, leading to false-positive test results and/or increased medicolegal risk for notfollowing up on abnormal test results (See 'Rationale for selective testing' above.)

●

We suggest baseline hemoglobin measurement for all patients 65 years of age or older who areundergoing major surgery and for younger patients undergoing surgery that is expected to result insignificant blood loss (Grade 2C) Hemoglobin measurement is not necessary for younger patientsundergoing minor surgery unless the history suggests anemia For other healthy patients, wesuggest NOT performing routine hemoglobin, white blood count, or platelet measurements (Grade 2B) (See 'Complete blood count' above.)

●

In the revised cardiac risk index, a serum creatinine >2.0 mg/dL (177 micromol/L) predictedpostoperative cardiac complications We suggest NOT obtaining a serum creatinine concentration,except in the following patients (Grade 2B) (see 'Renal function' above):

●

Patients over the age of 50 undergoing intermediate or high risk surgery

•Younger patients suspected of having renal disease, when hypotension is likely duringsurgery, or when nephrotoxic medications will be used

•

We suggest NOT testing for serum electrolytes, blood glucose, liver function, hemostasis, orurinalysis in the healthy preoperative patient (Grade 2B) We suggest pregnancy testing in allreproductive age women prior to surgery, rather than use of history-taking alone to determinepregnancy (Grade 2C) (See 'Laboratory studies' above.)

●

We suggest NOT ordering an electrocardiogram (ECG) for asymptomatic patients undergoinglow-risk surgical procedures

●

Use of UpToDate is subject to the Subscription and License Agreement.

J Am Coll Cardiol 2014; 64:e77

A preoperative resting ECG can be considered for asymptomatic patients undergoing surgery withelevated risk (risk of major adverse cardiac event ≥1 percent) This is discussed in detail

elsewhere (See 'Electrocardiogram' above and "Evaluation of cardiac risk prior to noncardiacsurgery", section on 'Initial preoperative evaluation'.)

We suggest that clinicians NOT order routine preoperative chest radiographs or pulmonary functiontests in the healthy patient (Grade 2B) We suggest obtaining a preoperative chest radiograph inpatients with cardiopulmonary disease and those older than 50 years of age who are undergoingabdominal aortic aneurysm surgery or upper abdominal/thoracic surgery (Grade 2C) (See 'Chestradiograph' above and 'Pulmonary function tests' above.)

●

Reilly DF, McNeely MJ, Doerner D, et al Self-reported exercise tolerance and the risk of seriousperioperative complications Arch Intern Med 1999; 159:2185.

Bradley KA, Rubinsky AD, Sun H, et al Alcohol screening and risk of postoperative complications

in male VA patients undergoing major non-cardiac surgery J Gen Intern Med 2011; 26:162