Transcript Principles of Preoperative and Operative Surgery

Principles of Preoperative
and Operative Surgery
Sabiston 2007
Presented in April 2008
By Dr. S. Noorshafiee
Preoperative Preparation of the Patient
 Systems Approach to Preoperative
Evaluation
 Additional Preoperative Considerations
 Preoperative Checklist

PREOPERATIVE PREPARATION
OF THE PATIENT

The modern preparation of a patient for
surgery is epitomized by the
convergence of the art and science of
the surgical discipline. The context in
which preoperative preparation is
conducted ranges from an outpatient
office visit to hospital inpatient
consultation to emergency department
evaluation of a patient.

Approaches to preoperative evaluation
differ significantly, depending on the
nature of the complaint and the
proposed surgical intervention, patient
health and assessment of risk factors,
and the results of directed
investigation and interventions to
optimize the patient's overall status
and readiness for surgery.

This chapter reviews the components of
risk assessment applicable to the
evaluation of any patient for surgery
and attempts to provide some basic
algorithms to aid in the preparation of
patients for surgery.
Determining the Need for
Surgery

Patients are often referred to surgeons
with a suspected surgical diagnosis and
the results of supporting investigations
in hand. In this context, the surgeon's
initial encounter with the patient may
be largely directed toward confirmation
of relevant physical findings and review
of the clinical history and laboratory
and investigative tests that support the
diagnosis.

A recommendation regarding the need
for operative intervention can then be
made by the surgeon and discussed with
the patient's family members. A
decision to perform additional
investigative tests or consideration of
alternative therapeutic options may
postpone the decision for surgical
intervention from this initial encounter
to a later time

It is important for the surgeon to
explain the context of the illness and
the benefit of different surgical
interventions, further investigation, and
possible nonsurgical alternatives, when
appropriate

The surgeon's approach to the patient
and family during the initial encounter
should be one that fosters a bond of
trust and opens a line of communication
among all participants. A professional
and unhurried approach is mandatory,
with time taken to listen to concerns
and answer questions posed by the
patient and family members.

The surgeon's initial encounter with a
patient should result in the patient
being able to express a basic
understanding of the disease process
and the need for further investigation
and possible surgical management. A
well-articulated follow-up plan is
essential.
Perioperative Decision Making

Once the decision has been made to
proceed with operative management, a
number of considerations must be
addressed regarding the timing and site
of surgery, the type of anesthesia, and
the preoperative preparation necessary
to understand the patient's risk and
optimize the outcome.

These components of risk assessment
take into account both the
perioperative (intraoperative period
through 48 hours postoperatively) and
the later postoperative (up to 30 days)
periods and seek to identify factors
that may contribute to patient
morbidity during these periods.
Preoperative Evaluation

The aim of preoperative evaluation is
not to screen broadly for undiagnosed
disease but rather to identify and
quantify any comorbidity that may have
an impact on the operative outcome

This evaluation is driven by findings on
the history and physical examination
suggestive of organ system dysfunction
or by epidemiologic data suggesting the
benefit of evaluation based on age,
gender, or patterns of disease
progression. The goal is to uncover
problem areas that may require further
investigation or be amenable to
preoperative optimization

Routine preoperative testing is not
cost-effective and, even in the elderly,
is less predictive of perioperative
morbidity than the American Society of
Anesthesiologists (ASA) status or
American Heart Association

The preoperative evaluation is
determined in light of the planned
procedure (low, medium, or high risk),
the planned anesthetic technique, and
the postoperative disposition of the
patient (outpatient or inpatient, ward
bed, or intensive care

In addition, the preoperative evaluation
is used to identify patient risk factors
for postoperative morbidity and
mortality.

If preoperative evaluation uncovers
significant comorbidity or evidence of
poor control of an underlying disease
process, consultation with an internist
or medical subspecialist may be required
to facilitate the workup and direct
management. In this process,
communication between the surgeon and
consultants is essential to define
realistic goals for this optimization
process and to expedite surgical
management
SYSTEMS APPROACH TO
PREOPERATIVE
EVALUATION
Cardiovascular

Cardiovascular disease is the leading
cause of death in the industrialized
world, and its contribution to
perioperative mortality during
noncardiac surgery is significant. Of the
27 million patients undergoing surgery in
the United States every year, 8 million,
or nearly 30%, have significant coronary
artery disease or other cardiac
comorbid conditions.

One million of these patients will
experience perioperative cardiac
complications, with substantial
morbidity, mortality, and cost.
Consequently, much of the preoperative
risk assessment and patient preparation
centers on the cardiovascular system.
One of the first anesthesia risk categorization
systems was the ASA classification. It has
five stratifications:
I—Normal healthy patient
II—Patient with mild systemic disease
III—Patient with severe systemic disease that
limits activity but is not incapacitating
IV—Patient who has incapacitating disease that
is a constant threat to life
V—Moribund patient not expected to survive
24 hours with or without an operation
There are more other systems for
evaluation of cardiovascular risk such
as:
Goldman cardiac risk index,1977
Detsky modified multifactorial index 1986
Eagle's Criteria for Cardiac Risk
Assessment, 1989
Revised Cardiac Risk Index

Once these data have been obtained,
the surgeon and consultants need to
weigh the benefits of surgery against
the risk and determine whether any
perioperative intervention will reduce
the probability of a cardiac event

This intervention usually centers on
coronary revascularization via coronary
artery bypass or percutaneous
transluminal coronary angioplasty but
may include modification of the choice
of anesthetic or the use of invasive
intraoperative monitoring

Patients who have undergone a
percutaneous coronary intervention with
stenting need to have elective
noncardiac procedures delayed for 4 to
6 weeks, although the delay may be
shortened depending on the type of
stent used (drug eluting versus non–drug
eluting

The optimal timing of a surgical
procedure after myocardial infarction
(MI) is dependent on the duration of
time since the event and assessment of
the patient's risk for ischemia, either
by clinical symptoms or by noninvasive
study
Any patient can be evaluated as a surgical
candidate after an acute MI (within 7
days of evaluation) or a recent MI
(within 7-30 days of evaluation). The
infarction event is considered a major
clinical predictor in the context of
ongoing risk for ischemia

The risk for reinfarction is generally
considered low in the absence of such
demonstrated risk. General
recommendations are to wait 4 to 6
weeks after MI to perform elective
surgery

Improvements in postoperative care
have centered on decreasing the
adrenergic surge associated with
surgery and halting platelet activation
and microvascular thrombosis

Perioperative risk for cardiovascular
morbidity and mortality was decreased
by 67% and 55%, respectively, in
ACC/AHA-defined medium- to high-risk
patients receiving β-blockers in the
perioperative period versus those
receiving placebo.

Although the benefit was most noticeable in
the 6 months after surgery, event-free
survival was significantly better in the group
that received β-blockers up to 2 years after
surgery.The current AHA/ACC
recommendations are to start β-blocker
therapy in medium- to high-risk patients
undergoing major- to intermediate-risk
surgery as early as possible preoperatively
and titrate to a heart rate of 60 beats per
minute. The choice of agent and duration of
therapy are still being debated

An easy, inexpensive method to
determine cardiopulmonary functional
status for noncardiac surgery is the
patient's ability or inability to climb two
flights of stairs. Two flights of stairs is
needed because it demands greater
than 4 metabolic equivalents (METs).

In a review of all studies of stair
climbing as preoperative assessment,
prospective studies have shown it to be
a good predictor of mortality associated
with thoracic surgery. In major
noncardiac surgery, an inability to climb
two flights of stairs is an independent
predictor of perioperative morbidity,
but not mortality.
Pulmonary

Preoperative evaluation of pulmonary
function may be necessary for either
thoracic or general surgical procedures.

Whereas extremity, neurologic, and
lower abdominal surgical procedures
have little effect on pulmonary function
and do not routinely require pulmonary
function studies, thoracic and upper
abdominal procedures can decrease
pulmonary function and predispose to
pulmonary complications

Accordingly, it is wise to consider
assessment of pulmonary function for
all lung resection cases, for thoracic
procedures requiring single-lung
ventilation, and for major abdominal and
thoracic cases in patients who are older
than 60 years, have significant
underlying medical disease, smoke, or
have overt pulmonary symptomatology

Necessary tests include forced
expiratory volume in 1 second (FEV1),
forced vital capacity, and the diffusing
capacity of carbon monoxide

Adults with an FEV1 of less than 0.8 L/sec, or
30% of predicted, have a high risk for
complications and postoperative pulmonary
insufficiency. Pulmonary resections need to be
planned so that the postoperative FEV1 is
greater than 0.8 L/sec, or 30% of predicted.
Such planning can be done with the aid of
quantitative lung scans, which can indicate
which segments of the lung are functional

Preoperative pulmonary assessment
determines not only factors that confer
increased risk but also potential targets
to reduce the risk for pulmonary
complications

General factors that increase risk for
postoperative pulmonary complications
include increasing age, lower albumin
level, weight loss, and possibly obesity

Concurrent comorbid conditions such as
impaired sensorium, previous stroke,
congestive heart failure, acute renal
failure, chronic steroid use, and blood
transfusion are also associated with
increased risk for postoperative
pulmonary complications

Specific pulmonary risk factors include
chronic obstructive pulmonary disease,
smoking, preoperative sputum
production, pneumonia, dyspnea, and
obstructive sleep apnea.

Preoperative interventions that may
decrease postoperative pulmonary
complications include smoking cessation (>2
months before the planned procedure),
bronchodilator therapy, antibiotic therapy
for preexisting infection, and pretreatment
of asthmatic patients with steroids.
Perioperative strategies include the use of
epidural anesthesia, vigorous pulmonary
toilet and rehabilitation, and continued
bronchodilator therapy.
Renal

Approximately 5% of the adult
population have some degree of renal
dysfunction that can affect the
physiology of multiple organ systems
and cause additional morbidity in the
perioperative period. In fact, a
preoperative creatinine level of 2.0
mg/dL or higher is an independent risk
factor for cardiac complications

Identification of coexisting
cardiovascular, circulatory, hematologic,
and metabolic derangements secondary
to renal dysfunction are the goals of
preoperative evaluation in these
patients

A patient with known renal insufficiency
undergoes a thorough history and
physical examination with particular
questioning about previous MI and
symptoms consistent with ischemic
heart disease. The cardiovascular
examination seeks to document signs of
fluid overload. The patient's functional
status and exercise tolerance are
carefully elicited.

Diagnostic testing for patients with
renal dysfunction include an
electrocardiogram (ECG), serum
chemistry panel, and complete blood
count (CBC). If physical examination
findings are suggestive of heart failure,
a chest radiograph may be helpful

Urinalysis and urinary electrolyte
studies are not often helpful in the
setting of established renal
insufficiency, although they may be
diagnostic in patients with new-onset
renal dysfunction.

Laboratory abnormalities are often seen
in a patient with advanced renal
insufficiency. Some metabolic
derangements in a patient with
advanced renal failure may be mild and
asymptomatic and are revealed by
electrolyte or blood gas analysis

Anemia, when present in these patients,
may range from mild and asymptomatic
to that associated with fatigue, low
exercise tolerance, and exertional
angina. Such anemia can be treated with
erythropoietin or darbepoietin
preoperatively or perioperatively

Because the platelet dysfunction
associated with uremia is often a
qualitative one, platelet counts are
usually normal. A safe course is to
communicate with the anesthesiologist
the potential need for agents to be
available in the operating room to assist
in improving platelet function.

Pharmacologic manipulation of
hyperkalemia, replacement of calcium
for symptomatic hypocalcemia, and the
use of phosphate-binding antacids for
hyperphosphatemia are often required.

Sodium bicarbonate is used in the
setting of metabolic acidosis not caused
by hypoperfusion when serum
bicarbonate levels are below 15 mEq/L.
It can be administered in intravenous
(IV) fluid as 1 to 2 ampules in a 5%
dextrose solution

Hyponatremia is treated by volume
restriction, although dialysis is
commonly required within the
perioperative period for control of
volume and electrolyte abnormalities

Patients with chronic end-stage renal
disease undergo dialysis before surgery
to optimize their volume status and
control the potassium level.
Intraoperative hyperkalemia can result
from surgical manipulation of tissue or
transfusion of blood. Such patients are
often dialyzed on the day after surgery
as well

Prevention of secondary renal insults in
the perioperative period include the
avoidance of nephrotoxic agents and
maintenance of adequate intravascular
volume throughout this period. In the
postoperative period, the
pharmacokinetics of many drugs may be
unpredictable, and adjustments in dosage
need to be made according to pharmacy
recommendation.

In the acute setting, patients who have
stable volume status can undergo
surgery without preoperative dialysis,
provided that no other indication exists
for emergency dialysis.

Notably, narcotics used for
postoperative pain control may have
prolonged effects despite hepatic
clearance, and nonsteroidal agents are
avoided in patients with renal
insufficiency.
Principles of Preoperative
and Operative Surgery
Sabiston 2007
Presented in April 2008
By Dr. S. Noorshafiee
SYSTEMS APPROACH TO
PREOPERATIVE
EVALUATION
Hepatobiliary

Hepatic dysfunction may reflect the
common pathway of a number of insults
to the liver, including viral-, drug-, and
toxin-mediated disease. A patient with
liver dysfunction requires careful
assessment of the degree of functional
impairment, as well as a coordinated
effort to avoid additional insult in the
perioperative period

A history of any exposure to blood and
blood products or exposure to
hepatotoxic agents is obtained. Patients
frequently know whether hepatitis has
been diagnosed and need to be
questioned about when the diagnosis
was made and what activity led to the
infection

Although such a history may not affect
further patient evaluation, it is
important to obtain in case an operative
team member is injured during the
planned surgical procedure.

A review of systems specifically
inquires about symptoms such as
pruritus, fatigability, excessive
bleeding, abdominal distention, and
weight gain. Evidence of hepatic
dysfunction may be seen on physical
examination

Jaundice and scleral icterus may be
evident with serum bilirubin levels
higher than 3 mg/dL. Skin changes
include spider angiomas, caput medusae,
palmar erythema, and clubbing of the
fingertips. Abdominal examination may
reveal distention, evidence of fluid
shift, and hepatomegaly.
Encephalopathy or asterixis may be
evident. Muscle wasting or cachexia can
be prominent

A patient with liver dysfunction
undergoes standard liver function tests.
Elevations in hepatocellular enzymes
may suggest a diagnosis of acute or
chronic hepatitis, which can be
investigated by serologic testing for
hepatitis A, B, and C. Alcoholic hepatitis
is suggested by lower transaminase
levels and an aspartate/alanine
transaminase ratio (AST/ALT) greater
than 2

Laboratory evidence of chronic
hepatitis or clinical findings consistent
with cirrhosis is investigated with tests
of hepatic synthetic function, notably
serum albumin, prothrombin, and
fibrinogen

Patients with evidence of impaired
hepatic synthetic function also have a
CBC and serum electrolyte analysis.
Type and screen is indicated for any
procedure in which blood loss could be
more than minimal.

In the event of an emergency situation
requiring surgery, such an investigation
may not be possible. A patient with
acute hepatitis and elevated
transaminases is managed
nonoperatively, when feasible, until
several weeks beyond normalization of
laboratory values.

Urgent or emergency procedures in
these patients are associated with
increased morbidity and mortality. A
patient with evidence of chronic
hepatitis may often safely undergo
surgery

A patient with cirrhosis may be
assessed with the Child-Pugh
classification, which stratifies operative
risk according to a score based on
abnormal albumin and bilirubin levels,
prolongation of the prothrombin time
(PT), and the degree of ascites and
encephalopathy

This scoring system was initially applied
to predict mortality in cirrhotic
patients undergoing portacaval shunt
procedures, although it has been shown
to correlate with mortality in cirrhotic
patients undergoing a wider spectrum of
procedures as well.

Although the figures may not represent
current risk for all types of abdominal
operations, little doubt exists that the
presence of cirrhosis confers additional
risk for abdominal surgery and that this
risk is proportional to the severity of
disease

Other factors that affect outcomes in
these patients are the emergency
nature of a procedure, prolongation of
the PT greater than 3 seconds above
normal and refractory to correction
with vitamin K, and the presence of
infection

Two common problems requiring surgical
evaluation in a cirrhotic patient are
hernia (umbilical and groin) and
cholecystitis. An umbilical hernia in the
presence of ascites is a difficult
management problem because
spontaneous rupture is associated with
increased mortality rates.

Elective repair is best after the ascites
has been reduced to a minimum
preoperatively, although the procedure
is still associated with mortality rates
as high as 14%.Repair of groin hernias in
the presence of ascites is less risky in
terms of both recurrence and mortality.

Several recent reports have shown
decreased rates of complication with
laparoscopic procedures performed in
cirrhotic patients. Among the bestdescribed procedures is laparoscopic
cholecystectomy performed in patients
with Child's class A through C. When
compared with open cholecystectomy,
less morbidity in terms of blood loss and
wound infection has been observed.

Malnutrition is common in cirrhotic
patients and is associated with a
reduction in hepatic glycogen stores and
reduced hepatic protein synthesis.
Patients with advanced liver disease
often have a poor appetite, tense
ascites, and abdominal pain. Attention
must be given to appropriate enteral
supplementation, as done for all patients
at significant nutritional risk.
Endocrine

A patient with an endocrine condition
such as diabetes mellitus,
hyperthyroidism or hypothyroidism, or
adrenal insufficiency is subject to
additional physiologic stress during
surgery.

The preoperative evaluation identifies
the type and degree of endocrine
dysfunction to permit preoperative
optimization. Careful monitoring
identifies signs of metabolic stress
related to inadequate endocrine control
during surgery and throughout the
postoperative course.

The evaluation of a diabetic patient for
surgery assesses the adequacy of
glycemic control and identifies the
presence of diabetic complications,
which may have an impact on the
patient's perioperative course.

The patient's history and physical
examination document evidence of
diabetic complications, including cardiac
disease, circulatory abnormalities, and
the presence of retinopathy,
neuropathy, or nephropathy

Preoperative testing may include fasting
and postprandial glucose and hemoglobin
A1c levels. Serum electrolyte, blood
urea nitrogen, and creatinine levels are
obtained to identify metabolic
disturbances and renal involvement.
Urinalysis may reveal proteinuria as
evidence of diabetic nephropathy.

An ECG is considered in patients with
long-standing disease. The existence of
neuropathy in diabetics may be
accompanied by cardiac autonomic
neuropathy, which increases the risk for
cardiorespiratory instability in the
perioperative period.

A diabetic patient requires special
attention to optimize glycemic control
perioperatively. Non–insulin-dependent
diabetics need to discontinue longacting sulfonylureas such as
chlorpropamide and glyburide because
of the risk for intraoperative
hypoglycemia; a shorter-acting agent or
sliding-scale insulin coverage may be
substituted in this period.

The use of metformin is stopped
preoperatively because of its
association with lacticacidosis in the
setting of renal insufficiency. An
insulin-dependent diabetic is told to
withhold long-acting insulin preparations
(Ultralente preparations) on the day of
surgery; lower dosages of intermediateacting insulin (NPH or Lente) are
substituted on the morning of surgery

These patients are scheduled for early
morning surgery, when feasible. During
surgery, a standard 5% or 10% dextrose
infusion is used with short-acting insulin
or an insulin drip to maintain glycemic
control

A patient with diabetes mellitus that is
well controlled by diet or oral
medication may not require insulin
perioperatively, but those with poorer
control or patients taking insulin may
require preoperative dosing and both
glucose and insulin infusion during
surgery

Frequent assessments of glucose levels
are continued through the postoperative
period. Current recommendations are to
maintain the perioperative glucose level
between 80 and 150 mg/dL, even in
patients not previously diagnosed as
being diabetic. Adequate hydration must
be maintained with avoidance of
hypovolemia.

Postoperative orders include frequent
(every 2-4 hours) finger stick glucose
checks and the use of short-acting
insulin in the form of sliding-scale
coverage. Twice-daily doses of
intermediate-acting insulin can be
supplemented with sliding-scale
coverage until the patient is eating and
can resume the usual regimen

Postoperative cardiac events can occur
with unusual manifestations in these
patients. Although chest pain needs to
be evaluated with ECG and serum
troponin levels, this same evaluation may
need to be done for new-onset dyspnea,
blood pressure alterations, or a
decrease in urine output

Adequate prophylaxis for deep venous
thrombosis (DVT) is essential because
of the increased risk for thrombosis.
The adequacy of perioperative glycemic
control has an impact on wound healing
and the risk for surgical site infection
Perioperative Diabetic
Management

Management of diabetic patients has
evolved over the past several years. The
introduction of new drugs for non–
insulin-dependent diabetics, in addition
to new types of insulin and new insulin
delivery systems in insulin-dependent
diabetics, has changed the way that
these patients are approached in the
perioperative period.

Rapid-acting (Lispro) and short-acting
(Regular) insulin preparations are usually
withheld when the patient stops oral
intake (NPO) and are used for acute
management of hyperglycemia during
the NPO period

intermediate-acting (NPH Lente) and longacting (Ultralente, Glargine) insulin
preparations are administered at two thirds
the normal pm dose the night before surgery
and half the normal am dose the morning of
surgery, with frequent bedside glucose
determinations and treatment with shortacting insulin as needed. An infusion of 5%
dextrose is initiated the morning of surgery

If the planned procedure is expected to
take a long time, an insulin infusion can
be administered, again with frequent
monitoring of blood glucose.
Insulin pumps are used by some patients
as their method of glucose management.
These pumps use short-acting insulin
and have a variable delivery rate that
can be programmed to more closely
simulate endogenous insulin production

On the day of surgery, the patient
continues with the basal insulin infusion.
The pump is then used to correct the
glucose level as it is measured. Patients
generally have a correction or
sensitivity factor that will decrease
their glucose by 50 mg/dL. It is
important to know this factor before
the planned surgical procedure so that
glucose can be managed in the operating
room

Patients who take oral hypoglycemic agents
typically withhold their normal dose the day
of surgery. Patients can resume their oral
agent once diet is resumed. Coverage for
hyperglycemia is with a short-acting insulin
preparation based on blood glucose
monitoring. An exception is metformin. If
the patient has altered renal function, this
agent needs to be discontinued until renal
function either normalizes or stabilizes.

patient with known or suspected thyroid
disease is evaluated with a thyroid
function panel. Evidence of
hyperthyroidism is addressed
preoperatively and surgery deferred
until a euthyroid state is achieved, when
feasible

These patients need to have their
electrolyte levels determined and an
ECG performed as part of their
preoperative evaluation. In addition, if
the physical examination suggests signs
of airway compromise, further imaging
may be warranted

A patient with hyperthyroidism who
takes antithyroid medication such as
propylthiouracil or methimazole is
instructed to continue this regimen on
the day of surgery

The patient's usual doses of β-blockers
or digoxin are also continued. In the
event of urgent surgery in a thyrotoxic
patient at risk for thyroid storm, a
combination of adrenergic blockers and
glucocorticoids may be required and are
administered in consultation with an
endocrinologist

Patients with newly diagnosed
hypothyroidism generally do not require
preoperative treatment, although they
may be subject to increased sensitivity
to medications, including anesthetic
agents and narcotics

Severe hypothyroidism can be
associated with myocardial dysfunction,
coagulation abnormality, and electrolyte
imbalance, notably hypoglycemia. Severe
hypothyroidism needs to be corrected
before elective operations
Hematologic

Hematologic assessment may lead to the
identification of disorders such as
anemia, inherited or acquired
coagulopathy, or a hypercoagulable
state. Substantial morbidity may derive
from failure to identify these
abnormalities preoperatively. The need
for perioperative prophylaxis for venous
thromboembolism must be carefully
reviewed in every surgical patient.

Anemia is the most common laboratory
abnormality encountered in preoperative
patients. It is often asymptomatic and
can require further investigation to
understand its cause. The history and
physical examination may uncover
subjective complaints of energy loss,
dyspnea, or palpitations, and pallor or
cyanosis may be evident

Patients are evaluated for
lymphadenopathy, hepatomegaly, or
splenomegaly, and pelvic and rectal
examinations are performed. A CBC,
reticulocyte count, and serum iron, total
iron-binding capacity, ferritin, vitamin
B12, and folate levels are obtained to
investigate the cause of anemia.

The decision to transfuse a patient
perioperatively is made with
consideration of the patient's
underlying risk factors for ischemic
heart disease and the estimated
magnitude of blood loss during surgery.

Generally, patients with normovolemic
anemia without significant cardiac risk
or anticipated blood loss can be
managed safely without transfusion,
with most healthy patients tolerating
hemoglobin levels of 6 or 7 g/dL
Guidelines for Red Blood Cell
Transfusion for Acute Blood Loss
Evaluate the risk for ischemia
 Estimate/anticipate the degree of
blood loss. Less than 30% rapid volume
loss probably does not require
transfusion in a previously healthy
individual


Measure the hemoglobin concentration:
<6 g/dL, transfusion usually required; 610 g/dL, transfusion dictated by clinical
circumstance; >10 g/dL, transfusion
rarely required

Measure vital signs/tissue oxygenation
when hemoglobin is 6-10 g/dL and the
extent of blood loss is unknown.
Tachycardia and hypotension refractory
to volume suggest the need for
transfusion; O2 extraction ratio >50%,
decreased Vo2, suggest that
transfusion is usually needed

All patients undergoing surgery are
questioned to assess their bleeding risk.
Coagulopathy may result from inherited
or acquired platelet or factor disorders
or may be associated with organ
dysfunction or medications

The inquiry begins with direct
questioning about a personal or family
history of abnormal bleeding.
Supporting information includes a
history of easy bruising or abnormal
bleeding associated with minor
procedures or injury.

A history of liver or kidney dysfunction
or recent common bile duct obstruction
needs to be elicited, as well as an
assessment of nutritional status.
Medications are carefully reviewed, and
the use of anticoagulants, salicylates,
nonsteroidal anti-inflammatory drugs
(NSAIDs), and antiplatelet drugs are
noted

Physical examination may reveal
bruising, petechiae, or signs of liver
dysfunction.

Patients with thrombocytopenia may
have qualitative or quantitative defects
as a result of immune-related disease,
infection, drugs, or liver or kidney
dysfunction.

Qualitative defects may respond to
medical management of the underlying
disease process, whereas quantitative
defects may require platelet
transfusion when counts are less than
50,000 in a patient at risk for bleeding

Although coagulation studies are not
routinely ordered, patients with a
history suggestive of coagulopathy
undergo coagulation studies before
surgery. Coagulation studies are also
obtained before the procedure if
considerable bleeding is anticipated or
any significant bleeding would be
catastrophic.

Patients with documented disorders of
coagulation may require perioperative
management of factor deficiencies,
often in consultation with a
hematologist

Patients receiving anticoagulation
therapy usually require preoperative
reversal of the anticoagulant effect. In
patients taking warfarin, the drug is
withheld for four scheduled doses
preoperatively to allow the international
normalized ratio (INR) to fall to the
range of 1.5 or less (assuming that the
patient is maintained at an INR of 2.03.0).

Additional recommendations for specific
diagnoses requiring chronic
anticoagulation are based on riskbenefit analysis. Patients with a recent
history of venous thromboembolism or
acute arterial embolism frequently
require perioperative IV heparinization
because of an increased risk for
recurrent events in the perioperative
period

Systemic heparinization can often be
stopped within 6 hours of surgery and
restarted within 12 hours
postoperatively. When possible, surgery
is postponed in the first month after an
episode of venous or arterial
thromboembolism. Patients taking
anticoagulants for less than 2 weeks for
pulmonary embolism (PE) or proximal
DVT are considered for inferior vena
cava filter placement before surgery

All surgical patients are assessed for
their risk for venous thromboembolism
and receive adequate prophylaxis
according to current guidelines.Patients
are questioned to elicit any personal or
family history suggestive of a
hypercoagulable state. Levels of protein
C, protein S, antithrombin III, and
antiphospholipid antibody can be
obtained

Risk factor stratification is achieved by
considering multiple factors, including
age, type of surgical procedure,
previous thromboembolism, cancer,
obesity, varicose veins, cardiac
dysfunction, indwelling central venous
catheters, inflammatory bowel disease,
nephrotic syndrome, pregnancy, and
estrogen or tamoxifen use.

A number of regimens may be
appropriate for prophylaxis of venous
thromboembolism, depending on
assessed risk.Such regimens include the
use of unfractionated heparin, lowmolecular-weight heparin, intermittent
compression devices, and early
ambulation. Initial prophylactic doses of
heparin can be given preoperatively,
within 2 hours of surgery.
ADDITIONAL PREOPERATIVE
CONSIDERATIONS

Older adults account for a
disproportionate percentage of surgical
patients. Risk assessment must
carefully consider the effect of
comorbid illness in this population.
Although age has been reported as an
independent risk factor for
postoperative mortality, this
observation may represent the
unmeasured aspects of comorbid
disease and the severity of illness.

In an older adult patient, the
preoperative evaluation seeks to
identify and quantify the magnitude of
comorbid disease and optimize the
patient's condition before surgery when
possible. Preoperative testing is based
on findings suggested in the history and
physical examination.

Generally, elderly patients have an ECG,
chest radiograph, CBC, and
determination of glucose, creatinine,
blood urea nitrogen, and albumin levels.
Additional preoperative studies are
based on the criteria discussed earlier
for evaluation of patient and procedural
risk.

Predicting and preventing postoperative
delirium are important aspects of the
perioperative care of the elderly.
Patients with three or more of the
following have a 50% risk for
postoperative delirium:

70 years or older; self-reported alcohol
abuse; poor cognitive status; poor
functional status; markedly abnormal
preoperative serum sodium, potassium,
or glucose level; noncardiac thoracic
surgery; and aortic aneurysm surgery.

This risk is explained to the patient and
the family along with the symptoms of
postoperative delirium. If delirium does
occur, metabolic and infectious causes
need to be investigated before labeling
the event as sundowning.
Nutritional Status

Evaluation of the patient's nutritional
status is part of the preoperative
evaluation. A history of weight loss
greater than 10% of body weight over a
6-month period or 5% over a month is
significant.

Albumin or prealbumin levels and immune
competence (as assessed by delayed
hypersensitivity reaction) may help
identify patients with some degree of
malnutrition, and physical findings of
temporal wasting, cachexia, poor
dentition, ascites, or peripheral edema
may be corroborative. The degree of
malnutrition is estimated on the basis of
weight loss, physical findings, and
plasma protein assessment

The adequacy of a nutritional regimen
can be confirmed with a number of
serum markers. Albumin (half-life, 14-18
days), transferrin (half-life, 7 days),
and prealbumin (half-life, 3-5 days)
levels can be determined on a regular
basis in hospitalized patients.

These proteins are responsive to stress
conditions, however, and their synthesis
may be inhibited in the immediate
perioperative period. Once a patient is
on a stable regimen and in the anabolic
phase of recovery, these markers
reflect the adequacy of nutritional
efforts.

The effect of perioperative nutritional
support on outcomes has been studied in
a number of trials.

Patients with severe malnutrition (as
defined by a combination of weight loss,
visceral protein indicators, and
prognostic indices) appear to benefit
most from preoperative parenteral
nutrition, as demonstrated in study
groups treated with total parenteral
nutrition for 7 to 10 days before
surgery for gastrointestinal malignancy

The majority of studies show a
reduction in the rate of postoperative
complications from approximately 40%
to 30%. The use of total parenteral
nutrition postoperatively in similar
groups of patients is associated with an
approximately 10% increase in
complication rates

Well-nourished patients undergoing
surgery do not appear to benefit from
aggressive perioperative nutritional
support; parenteral nutrition is
additionally associated with increased
septic complications.

Generally, nutritional support begins
within 5 to 10 days after surgery in all
patients unable to resume their normal
diet. Such support may take the form of
nasoenteric feeding, parenteral
nutrition, or a combination of the two
Obesity

The perioperative mortality rate is
significantly increased in patients with
clinically severe obesity (body mass
index [BMI] >40 kg/m2 or BMI >35
kg/m2 with significant comorbid
conditions). The goal of preoperative
evaluation of an obese patient is to
identify risk factors that might modify
perioperative care of the patient.

Clinically severe obesity is associated
with a higher frequency of essential
hypertension, pulmonary hypertension,
left ventricular hypertrophy, congestive
heart failure, and ischemic heart
disease

Patients with no or one of these risk
factors receive a β-blocker
preoperatively for cardioprotection.
Patients with two or more risk factors
undergo noninvasive cardiac testing
preoperatively

Obesity is also a risk factor for
postoperative wound infection. The rate
of wound infections is much lower with
laparoscopic surgery in this group, which
could have a bearing on selection of the
operative approach. Obesity is an
independent risk factor for DVT and PE;
therefore, appropriate prophylaxis is
instituted in these patients.
PREOPERATIVE CHECKLIST

preoperative evaluation concludes with a
review of all pertinent studies and
information obtained from investigative
tests. Documentation of this review is
made in the chart, which represents an
opportunity to ensure that all necessary
and pertinent data have been obtained
and appropriately interpreted

Informed consent after discussion with
the patient and family members
regarding the indication for the
anticipated surgical procedure, as well
as its risks and proposed benefits, are
documented in the chart. The
preoperative checklist also gives the
surgeon an opportunity to review the
need for β-blockade, DVT prophylaxis,
and prophylactic antibiotics.

Preoperative orders are written and
reviewed. The patient receives written
instructions regarding the time of
surgery and management of special
perioperative issues such as fasting,
bowel preparation, and medication use.
Antibiotic Prophylaxis

Appropriate antibiotic prophylaxis in
surgery depends on the most likely
pathogens encountered during the
surgical procedure. The type of
operative procedure is helpful in
deciding the appropriate antibiotic
spectrum and is considered before
ordering or administering any
preoperative medication.

Prophylactic antibiotics are not
generally required for clean (class I)
cases, except in the setting of
indwelling prosthesis placement or when
bone is incised. Patients who undergo
class II procedures benefit from a
single dose of an appropriate antibiotic
administered before the skin incision.

For abdominal (hepatobiliary,
pancreatic, gastroduodenal) cases,
cefazolin is generally used.
Contaminated (class III) cases require
mechanical preparation or parenteral
antibiotics with both aerobic and
anaerobic activity.

Such an approach is taken in the setting
of emergency abdominal surgery, as for
suspected appendicitis, and in trauma
cases. Dirty or infected cases often
require the same antibiotic spectrum,
which can be continued into the
postoperative period in the setting of
ongoing infection or delayed treatment.
The appropriate antibiotic is chosen
before surgery and administered before
the skin incision is made Repeat dosing
occurs at an appropriate interval, usually
3 hours for abdominal cases or twice
the half-life of the antibiotic, although
the patient's renal function may alter
the timing

Perioperative antibiotic prophylaxis
generally is not continued beyond the
day of surgery. With the advent of
minimal-access surgery, the use of
antibiotics seems less justified because
the risk for wound infection is
extremely low.

For example, routine antibiotic
prophylaxis in patients undergoing
laparoscopic cholecystectomy for
symptomatic cholelithiasis is of
questionable value. It may have a role,
however, in cases that result in
prosthetic graft (i.e., mesh) placement,
such as laparoscopic hernia repair.
Preoperative Mechanical Bowel
Cleansing

Mechanical bowel preparation with the
addition of oral antibiotics was the
standard of care for several decades
for any intestinal surgery. More recent
studies have evaluated the need for
both oral antibiotics and mechanical
cleansing

Oral antibiotics confer no benefit to
the patient and may increase the risk
for postoperative infection with
Clostridium difficile. In addition,
although it seems intuitive that removal
of bulk fecal material would decrease
the risk for anastomotic and infectious
complications, the opposite is true.

A recent meta-analysis showed that
both of these events are not decreased
and may be increased with mechanical
cleansing.
Review of Medications

Careful review of the patient's home
medications is a part of the
preoperative evaluation before any
operation; the goal is to appropriately
use medications that control the
patient's medical illnesses while
minimizing the risk associated with
anesthetic-drug interactions or the
hematologic or metabolic effects of
some commonly used medications and
therapies

The patient is asked to name all
medications, including psychiatric drugs,
hormones, and alternative/herbal
medications, and to provide dosages and
frequency.

In general, patients taking cardiac
drugs, including β-blockers and
antiarrhythmics, pulmonary drugs such
as inhaled or nebulized medications, or
anticonvulsants, antihypertensives, or
psychiatric drugs are advised to take
their medications with a sip of water on
the morning of surgery.

Parenteral forms or substitutes are
available for many drugs and may be
used if the patient remains NPO for any
significant period postoperatively. It is
important to return patients to their
normal medication regimen as soon as
possible

Two notable examples are the additional
cardiovascular morbidity associated
with the perioperative discontinuation
of β-blockers and rebound hypertension
with abrupt cessation of the
antihypertensive clonidine. Medications
such as lipid-lowering agents or vitamins
can be omitted on the day of surgery.

Some drugs are associated with an
increased risk for perioperative
bleeding and are withheld before
surgery. Drugs that affect platelet
function are withheld for variable
periods: aspirin and clopidogrel (Plavix)
are withheld for 7 to 10 days, whereas
NSAIDs are withheld between 1 day
(ibuprofen and indomethacin) and 3 days
(naproxen and sulindac), depending on
the drug's half-life

Because the use of estrogen and
tamoxifen has been associated with an
increased risk for thromboembolism,
they probably need to be withheld for a
period of 4 weeks preoperatively

The widespread use of herbal
medications has prompted review of the
effects of some commonly used
preparations and their potential adverse
outcomes in the perioperative period.
These substances may fail to be
recorded in the preoperative evaluation,
although important metabolic and
hematologic effects can result from
their regular use

Generally, the use of herbal medications
is stopped preoperatively, but this
needs to be done with caution in
patients who report the use of valerian,
which may be associated with a
benzodiazepine-like withdrawal
syndrome.
Preoperative Fasting

The standard order of “NPO past
midnight” for preoperative patients is
based on the theory of reduction of
volume and acidity of the stomach
contents during surgery. Recently,
guidelines have recommended a shift to
allow a period of restricted fluid intake
up to a few hours before surgery

The ASA recommends that adults stop
intake of solids for at least 6 hours and
clear fluids for 2 hours. When the
literature was recently reviewed by the
Cochrane group, they found 22 trials in
healthy adults that provided 38
controlled comparisons.

Very few trials investigated the fasting
routine in patients at higher risk for
regurgitation/aspiration (pregnant,
elderly, obese, or those with stomach
disorders). There is also increasing
evidence that preoperative
carbohydrate supplementation is safe
and may improve a patient's response to
perioperative stress

There was no evidence that the volume
or pH of gastric contents differed with
the length and type of fasting. Though
not reported in all the trials, there did
not appear to be an increased risk for
aspiration/regurgitation with a
shortened period of fasting.

Surgeons and anesthesiologists should
evaluate the evidence and consider
adjusting their standard fasting
policies.