Cases & Commentaries

Beeline to Spine

Spotlight Case
Commentary By Gerald W. Smetana, MD

Case Objectives

  • Understand the elements of preoperative
    medical evaluation.
  • Appreciate the limited role for
    preoperative laboratory testing.
  • Appreciate the importance of
    communication and collaboration between providers before
    surgery.
  • Discuss the value of preoperative
    clinics.

Case & Commentary: Part 1

An 83-year-old man with coronary artery
disease, mild heart failure, a history of repaired abdominal aortic
aneurism (AAA), and prior lumbar disk disease (status post L5-S1
fusion) was scheduled for a fusion-augmentation surgery by
orthopedics. The patient noted a bulging mass in the middle of his
abdomen a few months prior to surgery but did not report this to
his providers. Laboratory tests sent for a voluntary medical
research study showed an elevated alkaline phosphatase to nearly
800 U/L. These results were reviewed by his primary physician, but
no action was taken.

Preoperatively, the patient was evaluated by
both the anesthesiology and surgery teams. Given the prior AAA
repair, the patient underwent surgery in the supine position. The
fusion augmentation was uneventful, and he was discharged
home.

The decision to undergo major surgery requires a
careful assessment of the risks and benefits of the proposed
procedure. This assessment must appreciate the reality that surgery
is a morbid event. For example, the mean 30-day mortality rate in a
recent study of 5878 patients undergoing major surgery was
1.5%.(1)
Perioperative mortality rates, stratified by American Society of Anesthesiologists' (ASA) Physical
Status Class
for class I through V, were 0%, 0.2%, 2.2%, 15.2%,
and 70%.(1)
Postoperative medical complications represent an important source
of this morbidity and mortality. The most important medical
complications are cardiac, pulmonary, and venous thromboembolic.
Preoperative medical evaluation should include a consideration of
each of these three sources of risk.

More broadly, clinicians performing a routine
preoperative medical evaluation should address several issues. The
first is to identify factors that would increase the risk of
perioperative complications above baseline and to stratify risk for
the principal complications. The second issue to consider is
whether preoperative laboratory testing would add to this risk
assessment or potentially uncover important risks that would have
escaped clinical detection. The next step is to recommend
strategies to reduce these risks to the extent that they are
modifiable. Finally, the preoperative medical evaluation provides
an opportunity for collaboration between medicine, surgery, and
anesthesia colleagues. Instances in which such collaboration is
particularly important include identification of a previously
unrecognized important risk factor, a determination that the risks
of the surgery may potentially exceed the benefits, or a
recommendation for risk reduction strategies that include the
intraoperative and immediate postoperative period.

A careful history is the most important element
of the preoperative evaluation. This history seeks evidence for
major risk factors for medical complications as well as factors
that would influence anesthetic technique and management. Many
institutions have developed standardized checklist forms to
facilitate the anesthesiologist's preoperative evaluation.
Table
1
provides one published questionnaire and the degree of
concordance between patient responses and an evaluation by an
anesthesiologist.(2) The
medical consultant typically does not use a standardized
questionnaire but focuses in detail on the impact of established
chronic illnesses and potential risk factors for major
postoperative medical complications. Guidelines exist to estimate
risk of cardiac, pulmonary, and venous thromboembolic
complications.(3-6)

Routine preoperative laboratory testing adds
little to the clinical estimate of risk. Abnormal tests are
uncommon, and most can be predicted on the basis of known medical
problems. For example, a large review of a broad array of potential
tests found that the incidence of abnormalities that influenced
preoperative management ranged from 0%–3% (Table 2).(7) In
all cases, the negative likelihood ratio approached one (meaning
that a normal test result does not materially reduce the risk of
medical complications). The impact of positive test results is
modest; positive likelihood ratios range from 0–4.3. Based on
these types of analyses, most institutions in recent years have
reduced the number of required preoperative tests. For example, the
National Institute for Clinical Excellence (NICE) in Great Britain
published recommended standards in 2003.(8) If we apply these standards to our patient, he would
receive a complete blood count, renal function tests, and an
electrocardiogram. If we apply the recommendations of the above
mentioned systematic review (7), he
would also receive a chest x-ray.

In this 83-year-old patient, his age and
comorbidities would put him at higher risk for cardiac
complications, and to a lesser extent, pulmonary problems (back
surgery is an intrinsically low-risk procedure for pulmonary
complications). According to the Revised Cardiac Risk Index, his
estimated risk for postoperative cardiac complications would be
6.6% (9),
representing the source of his greatest potential morbidity. His
preoperative assessment, including recommendations for risk
reduction strategies, should focus on this area. He should also
receive appropriate prophylaxis to reduce the risk for surgical
site infection (SSI) (10)
and venous thromboembolism (VTE).(6) In
most institutions, these two areas of prophylaxis are standardized
according to a particular surgical specialty and the nature of the
specific procedure. In such a scenario, every patient would receive
the same SSI and VTE prophylaxis unless a specific contraindication
existed. For example, according to standardized, preprinted,
routine preoperative orders for back surgery, he may receive a
single intravenous dose of 1 gram of cefazolin within 1 hour before
the incision. Thus, the responsibility in this case for ensuring
that the patient receives SSI and VTE prophylaxis would normally
fall to the surgeon.

Case & Commentary: Part 2

One week later, the patient was readmitted
with frank jaundice, abdominal pain, and diarrhea. Physical
examination revealed a 4x4 cm, easily palpable mass protruding from
his mid-abdomen. Computed tomography (CT) scan revealed a widely
metastatic pancreatic cancer. There was massive tumor burden along
the peritoneum and adjacent to stomach, liver, and bowels. A cancer
antigen (CA) 19-9 level was extremely high. When told of his
diagnosis of metastatic cancer, the patient immediately said that
he wished he had never undergone the spinal surgery.

This response from the patient is completely
expected and reasonable. Had he known that he had unresectable
pancreatic cancer, with a likely life expectancy of less than 6
months, the most reasonable approach would have been to cancel
elective back surgery. Instead, he underwent unnecessary surgery
that conferred risk, took time from his remaining months of life,
and resulted in a potential for postoperative pain and
complications.

There were several opportunities to prevent this
error. The patient had abnormalities in all three elements of the
preoperative evaluation: the history, physical examination, and
laboratory tests. A careful history that included an open-ended
question such as "Do you have any other symptoms or concerns about
your health that we didn't already discuss today?" may have
captured his concern about the abdominal mass.

According to this case scenario, the abdominal
mass was easily palpated; it almost certainly would have been of
similar size during his preoperative evaluation. However, I can't
fault his physicians on this point. A "complete" physical
examination, such as that which would be performed as part of a
periodic health exam in a primary care setting, is not required
before elective surgery. Examination of the abdomen would not
normally be part of the minimum required physical examination
before back surgery. A suggested minimum examination includes vital
signs and an assessment of the airway, chest, and heart.(11)
Additional examination elements would be based on his medical
history. So we fall back to the history: did the patient mention
the mass or abdominal pain? If he had, each involved physician
would have had an opportunity to identify the mass on
examination.

Should the elevated alkaline phosphatase have
been a clue to his underlying cancer? Unfortunately, in the
fragmented system of American health care, the operative team's
ability to access laboratory results (or other key patient data)
often depends on whether this test was part of the patient's
hospital medical record and whether his primary care doctor used
the hospital laboratory for blood tests. If a test was performed by
an outside laboratory as part of the medical research study, as in
this case, only a paper copy may have been in the doctor's office
records. If the primary care doctor was community based, and not
part of hospital-based practice at the site where his surgery was
planned, this test result may not have been available to other
physicians involved in his care. Obviously, this situation begs for
a unified medical record [such as if the community-based primary
care physician used an electronic medical record (EMR) that was
part of the hospital's network] or other methods for patient data
to cross silos of care.

Communication in the preoperative setting is
particularly challenging when physicians practice in different
sites and have no access to each other's medical records. In such a
setting, each doctor has a responsibility to follow through on any
identified factors that may increase risk. This may require a phone
call or an email communication to be sure that all doctors are "on
the same page." Mandatory formal preoperative assessment clinics
are one strategy to identify patients who need additional
preoperative evaluation, optimize medical conditions, and
potentially improve outcomes. In one study, for example,
anesthesiologists developed a preoperative assessment clinic for
patients undergoing vascular surgery, a procedure with a
particularly high morbidity and mortality rate.(12) Among 234 patients seen in this clinic, the
anesthesiologist identified 26 patients who required further
evaluation or were unsuitable for surgery due to significant
comorbidities. Despite a modest sample size, the authors found a
significant reduction in mortality rates among patients undergoing
infrarenal aneurysm repair who visited the preoperative clinic when
compared to those who received usual care (4.8% vs. 14.5%). In
another study at Brigham and Women's Hospital in Boston, 565 of
5083 patients seen in a preoperative clinic required further
information regarding known medical problems, and the authors
identified an additional 115 patients with new medical
problems.(13)
Among the patients with new problems, 20% required review of
previous medical records or test results (as could have potentially
been the case in this patient) and 80% required additional testing
or consultation.

Patients at highest risk for poorly coordinated
care are those with multiple physicians, those without a primary
care physician who is actively involved in their care, those who
receive care from doctors who belong to different health delivery
systems with separate information technology systems, those from
disadvantaged settings who receive much of their primary care in
emergency departments, and those who are less medically literate
and are thus less able to describe their detailed medical
histories.

Case & Commentary: Part 3

Review of the preoperative assessment by
anesthesia and orthopedics revealed no mention of an epigastric
mass nor of the markedly abnormal alkaline phosphatase.

Unfortunately, no clear guidelines or written
policy statements articulate the ultimate responsibility of each
physician before surgery. As a generally accepted standard of care,
the consulting primary care physician would be responsible for
evaluating all factors that play into the risk-benefit
considerations before surgery. In most instances, the primary care
physician would have access to the most complete set of medical
records and, by virtue of a long-term relationship with the
patient, would be most likely to know all details of the relevant
past medical history.

With regard to laboratory data (such as the
alkaline phosphatase), evidence suggests that a normal test result
obtained within the past 4 months can be used as a preoperative
test as long as there has been no change in the clinical status of
the patient.(14)
The primary care physician is responsible for reviewing recent
laboratory tests to determine if any results impact preoperative
assessment, and to determine which, if any, should be repeated
before surgery.

Alkaline phosphatase would never be a routine
preoperative test.(7)
However, the abnormal finding of a markedly elevated result in this
patient would require further evaluation, independent of the
planned upcoming surgery. In an elderly man, cancer (pancreatic,
biliary, liver, or metastatic disease to liver) would be the most
likely cause of an asymptomatic elevation of alkaline phosphatase.
Gallstone disease or intrahepatic cholestasis would each be less
likely. It would be necessary to further evaluate the patient and
exclude cancer before any consideration of elective surgery. The
primary care physician not only failed to consider the impact of a
very high alkaline phosphatase on the risk for surgery, he or she
failed to undertake an appropriate evaluation independent of the
patient's planned back surgery.

The anesthesiologist conducting a preoperative
evaluation would normally not be expected to undertake a similarly
extensive evaluation nor to obtain office notes from the primary
care physician. The anesthesiologist's preoperative evaluation
would focus on factors that increase anesthetic risk or modify
anesthetic technique. The surgeon would usually defer to the
primary care physician regarding medical appropriateness for
surgery and the need for any further preoperative medical
evaluation. Having said this, it would still have been possible for
either of these physicians to have identified this cancer before
surgery by asking an open-ended question, such as "Do you have any
other health issues or concerns that you would like to discuss
before surgery?" or by performing a physical examination.

This case illustrates the importance of a
complete preoperative evaluation, the need for meticulous
communication among providers, and the potential pitfalls of
non-centralized medical information. Dedicated preoperative clinics
may reduce the risk of poor outcomes by uncovering risk factors and
by recommending additional evaluation or evidence-based risk
reduction strategies. The history and physical examination remain
the cornerstones of preoperative evaluation.

Take-Home Points

  • Preoperative medical evaluation requires
    a thorough history and physical examination, using open-ended
    questions.
  • Laboratory testing plays a limited role
    in risk stratification.
  • Communication and collaboration among
    providers before surgery are critical.
  • Preoperative clinics may aid in
    identifying risk factors for postoperative complications and may
    improve outcomes.
  • Patients should proceed to surgery only
    if the benefits exceed the risk.

Gerald W. Smetana, MD
Associate Professor of Medicine, Harvard Medical School
Division of General Medicine and Primary Care, Beth Israel
Deaconess Medical Center

Faculty Disclosure: Dr. Smetana
reported serving as course director for Harvard Medical
International—Novartis Schweiz. His commentary does not
include information regarding investigational or off-label use of
products or devices. All conflicts of interest have been resolved
in accordance with the ACCME Updated Standards for commercial
support.

References

1. Davenport DL, Bowe EA, Henderson WG, Khuri SF,
Mentzer RM Jr. National Surgical Quality Improvement Program
(NSQIP) risk factors can be used to validate American Society of
Anesthesiologists Physical Status Classification (ASA PS) levels.
Ann Surg. 2006;243:636-644.
[go to PubMed]

2. Hilditch WG, Asbury AJ, Jack E, McGrane S.
Validation of a pre-anaesthetic screening questionnaire.
Anaesthesia. 2003;58:874-877.
[go to PubMed]

3. Eagle KA, Berger PB, Calkins H, et al. ACC/AHA
guideline update for perioperative cardiovascular evaluation for
noncardiac surgery: executive summary: a report of the American
College of Cardiology/American Heart Association Task Force on
Practice Guidelines (Committee to Update the 1996 Guidelines on
Perioperative Cardiovascular Evaluation for Noncardiac Surgery). J
Am Coll Cardiol. 2002;39:542-553.
[go to PubMed]

4. Fleisher LA, Beckman JA, Brown KA, et al.
ACC/AHA 2006 guideline update on perioperative cardiovascular
evaluation for noncardiac surgery: focused update on perioperative
beta-blocker therapy: a report of the American College of
Cardiology/American Heart Association Task Force on Practice
Guidelines (Writing Committee to Update the 2002 Guidelines on
Perioperative Cardiovascular Evaluation for Noncardiac Surgery):
developed in collaboration with the American Society of
Echocardiography, American Society of Nuclear Cardiology, Heart
Rhythm Society, Society of Cardiovascular Anesthesiologists,
Society for Cardiovascular Angiography and Interventions, and
Society for Vascular Medicine and Biology. Circulation.
2006;113:2662-2674.
[go to PubMed]

5. Qaseem A, Snow V, Fitterman N, et al. Risk
assessment for and strategies to reduce perioperative pulmonary
complications for patients undergoing noncardiothoracic surgery: a
guideline from the American College of Physicians. Ann Intern Med.
2006;144:575-580.
[go to PubMed]

6. Geerts WH, Pineo GF, Heit JA, et al.
Prevention of venous thromboembolism: the Seventh ACCP Conference
on Antithrombotic and Thrombolytic Therapy. Chest. 2004;126(suppl
3):338S-400S.
[go to PubMed]

7. Smetana GW, Macpherson DS. The case against
routine preoperative laboratory testing. Med Clin North Am.
2003;87:7-40.
[go to PubMed]

8. Carlisle J, Langham J, Thoms G. Editorial I:
Guidelines for routine preoperative testing. Br J Anaesth.
2004;93:495-497.
[go to PubMed]

9. Lee TH, Marcantonio ER, Mangione CM, et al.
Derivation and prospective validation of a simple index for
prediction of cardiac risk of major noncardiac surgery.
Circulation. 1999;100:1043-1049.
[go to PubMed]

10. Bratzler DW, Hunt DR. The surgical infection
prevention and surgical care improvement projects: national
initiatives to improve outcomes for patients having surgery. Clin
Infect Dis. 2006;43:322-330.
[go to PubMed]

11. American Society of Anesthesiologists Task
Force on Preanesthesia Evaluation. Practice advisory for
preanesthesia evaluation: a report by the American Society of
Anesthesiologists Task Force on Preanesthesia Evaluation.
Anesthesiology. 2002;96:485-496.
[go to PubMed]

12. Cantlay K, Baker S, Parry A, Danjoux G. The
impact of a consultant anaesthetist led pre-operative assessment
clinic on patients undergoing major vascular surgery. Anaesthesia.
2006;61:234-239.
[go to PubMed]

13. Correll DJ, Bader AM, Hull MW, Hsu C, Tsen
LC, Hepner DL. Value of preoperative clinic visits in identifying
issues with potential impact on operating room efficiency.
Anesthesiology. 2006;105:1254-1259.
[go to PubMed]

14. Macpherson DS, Snow R, Lofgren RP.
Preoperative screening: value of previous tests. Ann Intern Med.
1990;113:969-973.
[go to PubMed]

Tables

Table 1. Sample Preoperative Screening
Questionnaire and Correlation with Anesthesiologist's
Evaluation

Question Criterion Validity*
1. Do you usually get chest pain or breathlessness
when you climb up two flights of stairs at normal speed?
Good
2. Do you have kidney disease? Moderate
3. Has anyone in your family (blood relatives) had
a problem following an anesthetic?
Undetermined
4. Have you ever had a heart attack? Excellent
5. Have you ever been diagnosed with an irregular
heartbeat?
Good
6. Have you ever had a stroke? Excellent
7. If you have been put to sleep for an operation,
were there any anesthetic problems?
Undetermined
8. Do you suffer from epilepsy or seizures? Yes
9. Do you have any problems with pain, stiffness,
or arthritis in your neck or jaw?
Excellent
10. Do you have thyroid disease? Excellent
11. Do you suffer from angina? Good
12. Do you have liver disease? Yes
13. Have you ever been diagnosed with heart
failure?
Yes
14. Do you suffer from asthma? Excellent
15. Do you have diabetes that requires
insulin?
Yes
16. Do you have diabetes that requires tablets
only?
Yes
17. Do you suffer from bronchitis? Excellent

*Criterion validity is the degree to which
patient responses to the questionnaire agree with the
anesthesiologist's evaluation. "Yes" indicates adequate criterion
validity.

Reprinted with permission from Blackwell
Publishing. Adapted with permission from Dr. Hilditch. In: Hilditch
WG, Asbury AJ, Jack E, McGrane S. Validation of a pre-anaesthetic
screening questionnaire. Anaesthesia. 2003;25:874-877.

Table 2. Recommendations for Laboratory
Testing before Elective Surgery*

Test Incidence of Abnormalities That Influence
Management (%)
LR+ LR– Indications
Hemoglobin 0.1 3.3 0.90 Anticipated major blood loss or symptoms of
anemia
White blood cell count 0.0 0.0 1.00 Symptoms suggest infection, myeloproliferative
disorder, or myelotoxic medications
Platelet count 0.0 0.0 1.00 History of bleeding diathesis, myeloproliferative
disorder, or myelotoxic medications
Prothrombin time (PT) 0.0 0.0 1.01 History of bleeding diathesis, chronic liver
disease, malnutrition, recent or long-term antibiotic use
Partial thromboplastin time (PTT) 0.1 1.7 0.86 History of bleeding diathesis
Electrolytes 1.8 4.3 0.80 Known renal insufficiency, congestive heart
failure, medications that affect electrolytes
Renal function 2.6 3.3 0.81 Age > 50 years, hypertension, cardiac disease,
major surgery, medications that may affect renal function
Glucose 0.5 1.6 0.85 Obesity or known diabetes
Liver function tests 0.1     No indication. Consider albumin measurement for
major surgery or chronic illness
Urinalysis 1.4 1.7 0.97 No indication
Electrocardiogram 2.6 1.6 0.96 Men > 40 years, women > 50 years, known
coronary artery disease, diabetes, or hypertension
Chest radiograph 3.0 2.5 0.72 Age > 50 years, known cardiac or pulmonary
disease, symptoms or exam suggest cardiac or pulmonary disease

*LR+ is positive likelihood ratio, LR– is
negative likelihood ratio.

Reprinted with permission from Elsevier Health
(USA). In: Smetana GW, Macpherson DS. The case against routine
preoperative laboratory testing. Med Clin North Am.
2003;87:7-40.