A preoperative evaluation is a responsibility of the anesthesiologist
and is a basic element of anesthesia care (Table
11–1). This evaluation consists of information gathered
from multiple sources, including the patient’s medical
record, history and physical examinations, and findings from medical
tests and consults or other evaluations performed prior to the patient being
seen by the anesthesiologist. Improved patient outcome and satisfaction
is the result of an adequate, structured, formal presurgical or
preprocedure evaluation and preparation performed on all patients.
The timing of the preoperative evaluation depends primarily on
the degree of planned surgical invasiveness. For high surgical invasiveness,
the initial assessment should be done at a minimum the day before
the planned procedure by the anesthesia staff. Patients undergoing medium
surgical invasive procedures can be evaluated the day before or
even on the day of surgery, and for low surgical invasiveness, the
initial assessment may be done the day of surgery. Time must be
allotted to follow up on conditions discovered during the preoperative visit
and to answer patient questions. Perioperative complications and
deaths are most often a combination of patient comorbidities, surgical
complexity, and anesthesia effects. The Physical Status Classification
of the American Society of Anesthesiologists is the best known of many
perioperative classification schemes (Table 11–2).
This classification system does not assign risk but is a common
language used to describe patients’ preoperative physical
status. The system is an alert to the anesthesia practitioner and
all members of the patient care team.
Table 11–2. American Society of Anesthesiologists Physical
Status Classification. |Favorite Table|Download (.pdf)
Table 11–2. American Society of Anesthesiologists Physical
|ASA 1 (PS1): A normal healthy patient|
|ASA 2 (PS2): A patient with mild systemic disease|
|ASA 3 (PS3): A patient with severe systemic disease|
|ASA 4 (PS4): A patient with severe systemic disease that
is a constant threat to life|
|ASA 5 (PS5): A moribund patient who is not expected to survive without
|ASA 6 (PS6): A declared brain-dead patient whose organs are being
removed for donor purposes|
Patients should ideally be seen in a PAC staffed by anesthesia
personnel who evaluate patients from the anesthetic perspective
and who look for physical conditions (airway) and controlled, uncontrolled,
or unrecognized medical conditions that can lead to perioperative
morbidity and mortality. There must be adequate communication between anesthesiologist
and surgeon such that any conditions that may result in patient
compromise are optimally addressed. Optimally, a patient’s
medical status has been adequately addressed by the patient’s
primary care physician prior to being referred to the PAC. However,
in some instances, only a cursory “cleared for anesthesia
and surgery” may result in a necessary delay. Any patients
other than healthy ASA 1 or 2 patients should be seen in a PAC.
Prior to referring patients to the PAC, the surgeon should have
already ordered the necessary preoperative labs and in many instances
will have already detected uncontrolled medical conditions that
require consultations from other specialties in order to recommend and
in some instances improve a patient’s status.
The optimal preoperative evaluation has the following two elements:
(1) content—readily accessible medical records, patient
interview, a directed preanesthesia examination, indicated preoperative laboratory tests, and additional consultations
when indicated; the minimum acceptable examination includes an assessment
of the airway, heart, and lungs well in advance of the planned date
of surgery; and (2) preoperativetests—only
as indicated by comorbidities and never as a screen, these tests
should be specifically aimed at helping the anesthesiologist formulate
an anesthetic plan.
Practice advisory for preanesthesia evaluation:
a report by the American Society of Anesthesiologists Task Force
on Preanesthesia Evaluation. Anesthesiology 2002;96:485.
The anesthesiologist should specifically ask the patient about
previous operations, anesthetic type, and any complications, eg,
allergic reactions, abnormal bleeding, delayed emergence, prolonged paralysis,
difficult airway management, awareness, or jaundice. Each of these describes
a possible specific anesthetic morbidity that must be further investigated
either by history or specific testing. Medical conditions detected
as decreased exercise tolerance, shortness of breath, orthopnea,
kidney or liver disease, and metabolic abnormalities, eg, diabetes
or thyroid disease, should be ascertained. A comprehensive history seeks
to identify serious cardiac conditions, eg, unstable coronary syndromes, angina,
myocardial infarctions either recent or past, decompensated congestive
heart failure, significant arrhythmias, or severe valvular disease.
Any recent changes in cardiac symptoms or other associated diseases,
eg, diabetes, renal disease, or cerebrovascular disease symptoms,
should be identified.
Any family history of adverse responses to anesthetics (malignant
hyperthermia) and social history of smoking, drug use, and alcohol
consumption is important. Finally, a comprehensive review of concurrent
medications including antihypertensives, insulin, bronchodilators,
or any other medications that can interact with anesthetic agents
should be documented. Certain medications may result in increased
or decreased anesthetic requirements, prolongation of muscle relaxants,
abnormal responses to sympathomimetics, delayed or enhanced metabolism
of anesthetics, and/or augmentation of the depressant effects
of anesthetics. The patient’s use of herbal medicines can
have an adverse reaction with some anesthetics (Table 11–3).
Table 11–3. Perioperative Effects of Common Herbal Medicine.1 |Favorite Table|Download (.pdf)
Table 11–3. Perioperative Effects of Common Herbal Medicine.1
|Name (Other Names)||Alleged Benefits||Perioperative Effects||Recommendations|
|Echinacea||Stimulates immune system||Allergic reactions; hepatotoxicity; interference with immune
suppressive therapy (eg, organ transplants)||Discontinue as far in advance of surgery as possible|
|Ephedra (ma huang)||Promotes weight loss; increases energy||Ephedrine-like sympathetic stimulation with increased heart
rate and blood pressure, arrhythmias, myocardial infarction, stroke||Discontinue at least 24 h prior to surgery; avoid monoamine oxidase
|Garlic (ajo)||Reduces blood pressure and cholesterol levels||Inhibition of platelet aggregation (irreversible)||Discontinue at least 7 days prior to surgery|
|Ginkgo (duck foot, maidenhair, silver apricot)||Improves cognitive performance (eg, dementia), increases
peripheral perfusion (eg, impotence, macular degeneration)||Inhibition of platelet-activating factor||Discontinue at least 36 h prior to surgery|
|Ginseng||Protects against “stress” and maintains “homeostasis”||Hypoglycemia; inhibition of platelet aggregation and coagulation cascade||Discontinue at least 7 days prior to surgery|
|Kava (kawa, awa, intoxicating pepper)||Decreases anxiety||GABA-mediated hypnotic effects my decrease MAC (see Chapter 7);
possible risk of acute withdrawal||Discontinue at least 24 h prior to surgery|
|St. John’s wort (amber, goatweed, Hypericum
perforatum, klamathe-weed)||Reverses mild to moderate depression||Inhibits serotonin, norepinephrine, and dopamine reuptake
by neurons; increases drug metabolism by induction of cytochrome
P-450||Discontinue at least 5 days prior to surgery|
|Valerian||Decreases anxiety||GABA-mediated hypnotic effects may decrease MAC; benzodiazepinelike
withdrawal syndrome||Taper dose weeks before surgery if possible; treat withdrawal
symptoms with benzodiazepines|
Ang-Lee MK, Moss J, Yuan C: Herbal medicines and
perioperative care. JAMA 2001;286:208.
After the vital signs are obtained, the physical examination
begins with the upper airway. Ability to control the airway is mandatory.
The focus of the examination is to assess those factors that would make
airway control (eg, endotracheal intubation) difficult or impossible.
Seven keys to the upper airway examination should be documented:
1. Range of motion of the cervical spine: Patients
should be asked to extend and flex their neck to the full range
of possible motion so the anesthesiologist may look for any limitations.
2. Thyroid cartilage to mentum distance: ideal is greater than
3. Mouth opening: ideal is greater than 3 cm.
4. Dentition: dentures, loose teeth, poor conservation.
5. Jaw protrusion: ability to protrude the lower incisors past
the upper incisors.
6. Presence of a beard.
7. Examination and classification of the upper airway based on
the size of patient’s tongue and the pharyngeal structures
visible on mouth opening with the patient sitting looking forward.
This visual description of the airway structures is known as the
Mallampati score (Figure 11–1):
I The soft palate, anterior and posterior tonsillar pillars,
and uvula are visible—suggests easy airway intubation.
II Tonsillar pillars and part of the uvula obscured by the tongue.
III Only soft palate and hard palate visible.
IV Only the hard palate is visible—suggests challenging airway.
Mallampati airway classification of oral opening. (Reproduced with permission from Morgan GE, MikhailMS,
Murray MJ: Clinical Anesthesiology, 4th ed. McGraw
The physical examination then focuses on heart and lungs, potential
intravenous catheter sites, and potential sites for regional anesthesia.
Range of motion of limbs must also be noted as this may affect positioning
in the operating room. Finally, any neurologic abnormalities must
When a metabolic or physical finding or symptom is discovered
during this visit, the anesthesiologist may believe that a specialty
consultation is necessary to suggest ways to optimize the patient
for surgery and anesthesia. If this is the case, the anesthesiologist
should communicate with the surgeon in order to prevent unnecessary
or unexpected delays in the surgical schedule. It is imperative
that any consults ordered be completed and the results be available
by the day of surgery.
The anesthesiologist can then advise the patient on appropriate
options for general anesthesia versus regional techniques based
on the patient’s history, physical examination, and type of
surgery. Although some surgical procedures must always be performed
under general anesthesia, the anesthesiologist may discuss other
options with the patient. If the referring surgeon has a particular
preference for a type of anesthetic, such preferences should be
communicated to the anesthesiologist directly rather than through
the patient. It is also best if the referring surgeon does not promise
any specific agent or technique without first consulting with the
anesthesia care givers.
Mallampati SR et al: A clinical sign to predict
difficult tracheal intubation: a prospective study. Can Anaesth
Soc J 1985;32:429.
The anesthesiologist must discuss with the patient the requirements
for preprocedure fasting and the management of medications up to
the time of surgery or procedure. Current guidelines for are as
follows: (1) No solid food should be eaten after the evening meal.
At the minimum, most anesthesiologists delay an anesthetic so that
the last solid food was 6–8 hours prior to nonemergent
surgery or procedures involving anesthesia. (2) NPO after midnight
except for sips of water to take oral medications. Water may be
ingested up to 2 hours before checking in for surgery. Some institutions
allow other clear liquids, eg, coffee, a few hours prior to surgery
or procedure. However, because surgery schedules can change abruptly
and procedure time may be moved forward, NPO after midnight is the
best policy. (3) Pediatric fasting guidelines vary among institutions,
so practitioners should consult with their particular pediatric
American Society of Anesthesiologists: Practice
guidelines for preoperative fasting and the use of pharmacologic agents
to reduce the risk of pulmonary aspiration: application to healthy patients
undergoing elective procedures. Anesthesiology 1999;90:896.
Drugs to Continue
Most antihypertensive medications and beta-blocking agents should
be continued in the perioperative period. There is some
controversy over whether or not certain classes of antihypertensives,
eg, angiotensin II receptor blockers (ARBs) (valsartan, candesartan,
losartan) or angiotensin-converting enzyme (ACE) inhibitors, should
be continued. Patients taking these medications occasionally experience
marked hypotension with induction of general anesthesia and respond
poorly to common vasopressors. Some practitioners recommend not taking
these drugs on the day of surgery. If the medication is continued,
then it is important to know which agents have been used. Smoking
should be stopped at least 2 weeks before scheduled surgery.
Comorbidities should be well controlled in the preoperative period
to avoid postprocedure morbidity, and even mortality.
Disease (Hypertension, Coronary Artery Disease, Congestive Heart Failure)
Hypertension is the most common preexisting medical disease identified
preoperatively and is a major risk factor for renal, cerebrovascular,
peripheral vascular, cardiac ischemia or infarction, and congestive
heart failure. The triad of lipid disorders, diabetes, and obesity
is classically found in patients with hypertension and should alert
the clinician that further evaluation for these conditions is needed.
Hypertension has an association with coronary artery disease, and
the preoperative evaluation is a unique opportunity to identify
and treat the nonessential causes of hypertension. The literature
strongly supports the notion that all hypertensive patients should
be treated medically to be as close to normotension as possible before
any planned surgical procedure. Diastolic pressures of 110 mm/Hg
or higher result in a higher incidence of intraoperative hypotension
and myocardial ischemia. However, the literature does not support
delaying surgery if the delay would be detrimental to the patient.
The introduction of perioperative selective beta-blocking drugs
provides a marked benefit in reducing the incidence of significant
myocardial ischemia during the perioperative period. Although somewhat
controversial, starting patients on beta-blockers immediately preoperatively
may have some risk, but any patient already taking beta-blockers
should continue taking the drug preoperatively.
Devereaux PJ et al: Rationale, design, and organization
of the Perioperative Ischemic Evaluation (POISE) trial: a randomized
controlled trial of metoprolol
versus placebo in patients undergoing
noncardiac surgery. Am Heart J
Spahn DR, Priebe HJ. Preoperative hypertension: remain wary? “Yes”—Cancel
surgery? “No.” Br J Anaesth 2004;92:461.
Ischemic heart disease is a leading cause of death in the United
States and is the leading cause of morbidity and mortality in the
perioperative period. About 25% of patients who present
for surgery each year have coronary artery disease, and thus much
of the preoperative evaluation focuses on detecting the presence
and degree of ischemic heart disease and determining whether it
is likely to impact anesthesia and surgery. A major goal of preoperative
assessment of cardiac status is to determine what, if any, interventions—coronary
artery bypass graft (CABG), percutaneous coronary intervention (PCI)—would
benefit patients undergoing noncardiac surgery. In general, preoperative
cardiac tests are recommended only if the information obtained will
lead to changes in patient management. However, certain active clinical
conditions (Table 11–4) demand evaluation
and treatment before noncardiac surgery. Determining which patient
characteristics indicate high perioperative risk is very difficult,
but preoperative congestive heart failure, recent myocardial infarction,
and unstable angina pose clear, significant clinical risk factors
(CRFs). Other CRFs include diabetes mellitus, renal insufficiency, cerebrovascular
disease, valvular heart disease, age, and dysrhythmias. Because
of the high incidence of silent ischemia, patients over the age
of 50 should have an electrocardiogram. A simple exercise tolerance
description of the functional capacity of the patient (eg, ability
to climb two flights of stairs without stopping) is also a practical
screening. This initial history by the surgeon or anesthesiologist
may be the first cardiac assessment the patient has ever had. The
assessment of functional capacity may be the first indication of
the need for further evaluation of potential cardiac pathology.
Table 11–4. Active
Cardiac Conditions for Which the Patient Should Undergo Evaluation
and Treatment Before Noncardiac Surgery. |Favorite Table|Download (.pdf)
Table 11–4. Active
Cardiac Conditions for Which the Patient Should Undergo Evaluation
and Treatment Before Noncardiac Surgery.
|Unstable coronary syndromes|
- Unstable or severe angina
- Recent myocardial infarction (>
7 but < 30 days ago)
- Decompensated heart failure (New York Heart Association class
IV): worsening or new onset
- Significant arrhythmias
- High-grade atrioventricular block
- Mobitz II atrioventricular
- Third-degree atrioventricular block
- Symptomatic ventricular
- Supraventricular arrhythmias (including atrial fibrillation
with uncontrolled ventricular rate [> 100] at
- Symptomatic bradycardia
- Newly recognized ventricular tachycardia
|Severe valvular disease|
- Severe aortic stenosis (mean pressure gradient > 40 mm Hg
or aortic valve area < 1.0 cm2 or symptomatic)
mitral stenosis (progressive dyspnea on exertion, exertional syncope,
or heart failure)
The American Heart Association (AHA) developed a useful algorithm
for all providers (Figure 11–2).
This algorithm, updated in 2007, no longer focuses on stress testing
but recommends testing only if the results could have an impact
on surgery or anesthesia and lead to changes in patient management.
The AHA guidelines state that most patients who have asymptomatic heart
disease can safely undergo elective noncardiac surgery without performing
invasive or even noninvasive cardiac testing. Having three or more
CRFs and planning for major vascular surgery may necessitate additional
cardiac testing. Those patients with one or two CRFs and who are
scheduled for intermediate risk surgery should either undergo additional cardiac
testing or proceed with planned surgery, in which case one of the
main goals of the anesthesiologist is to control heart rate.
Cardiac evaluation and care algorithm for noncardiac surgery based on active clinical conditions, known cardiovascular disease or cardiac risk factors for patients 50 years of age or greater. HR = heart rate, LOE = level of evidence, MET = metabolic equivalent. (Reprinted from Journal of the American College of Cardiology Vol
50, No 17, Fleisher LA, et al, ACC/AHA Guidelines on Perioperative
Cardiovascular Evaluation and Care for Noncardiac Surgery, Copyright
2007, with permission from Elsevier.)
Fleisher LA et al: ACC/AHA 2007 guidelines
on perioperative evaluation and care for noncardiac surgery. J Am
Coll Cardiol 2007;50:159.
with Prior PCI (Angioplasty and Stents)
There is much controversy about the best treatment for patients
who have had a PCI procedure, angioplasty without stents, or angioplasty
with either a bare metal or drug eluting stent. Because of the risk
for thrombosis at the site of intervention, patients are usually
placed on a dual antiplatelet therapy of aspirin and clopidogrel
for 2–4 weeks following angioplasty, 4–6 weeks
for the bare metal stents, and up to 1 year for the drug-eluting
stents. Stopping these antiplatelet drugs for a surgical intervention
that falls in the therapy period presents a risk for perioperative cardiac
events if the stent thromboses. The AHA guidelines recommend that
if the procedure is elective, then the operation should be postponed
until the case can be done with aspirin as the only antiplatelet
drug. If the operation is urgent, then consideration must be given
to the timing of the surgery and the risk of surgical bleeding.
If the risk of bleeding is low, then a PCI with a stent should be considered
and the patient placed on dual antiplatelet
therapy. If the bleeding risk is high, the AHA recommends the following based
on the timing of surgery: angioplasty for surgery within 14–29
days, bare metal stent for planned surgery within 30–365
days, and drug-eluting stent for surgery that can be delayed 1 year.
Truly urgent and/or emergent surgery necessitates angioplasty
for a procedure with a high risk of surgical bleeding and stenting
for a case with a low risk for bleeding.
The AHA guidelines recommend several other measures: (1) Perioperative
beta-blockade is indicated for patients previously on beta-blockers,
patients undergoing major vascular surgery, and patients undergoing
intermediate-risk surgery with one or more CRFs. Beta-blockade should
be started several days to weeks before planned surgery in order
to produce a consistent targeted heart rate between 65 and 70 beats
per minute. The addition of statin class agents, alpha-2 agonists,
and calcium channel blockers may also be effective. (2) Left ventricular
function should be assessed preoperatively for patients with unexplained
dyspnea or who have active or a history of compensated heart failure
with changing symptoms. (3) Coronary revascularization is suggested
for patients with left main disease, symptomatic three-vessel disease
and poor ejection fraction (EF), two-vessel disease with left anterior
descending coronary artery stenosis, poor EF and a positive stress
test, or an acute ST segment elevation myocardial infarction. AHA
does not recommend prophylactic CABG surgery in patients with stable
coronary artery disease. (4) Blood glucose should be tightly controlled.
(5) Patients with pacemakers or implanted defibrillator devices
should have them checked 3 to 6 months before major surgery. (6)
Patients with drug-eluting cardiac stents should continue aspirin
therapy and discontinue other antiplatelet agents for as short a
time as possible. (7) Beta-blockers and statin drugs should be continued
in the perioperative period. (8) Cardiology consultants should be asked
for specific recommendations that would reduce immediate perioperative
Riddell JW et al: Coronary stents and noncardiac
surgery. Circulation 2007;116:378.
The presence of significant pulmonary disease is suspected or
confirmed by the history and physical examination. Poor functional
capacity may be the first indication that further workup may be
necessary. The presence of either obstructive or restrictive lung
disease always puts the patient at risk for perioperative complications,
eg, pneumonia and prolonged difficulty weaning from the ventilator.
In some instances, arterial blood gas analysis or pulmonary function tests
are necessary to determine responsiveness to bronchodilators. Asthmatic
patients should be asked about the severity of their disease, hospitalizations,
responsiveness to inhalers, and steroid usage. There is no value
for routine preoperative chest x-rays. Surgical history and physical examination
may be the first indication of significant pulmonary disease, and
workup may be initiated before sending the patient to the PAC. Optimally,
patients who smoke should stop smoking at least 8 weeks before scheduled surgery.
Warner demonstrated that the highest rate of pulmonary complications
in 200 patients undergoing CABG was in those who had stopped smoking
1 to 8 weeks preoperatively. Recent cessation of cigarette smoking
may pose a greater risk of pulmonary complication because of the
commonly observed increase in cough and sputum production.
Warner DO: Helping surgical patients quit smoking:
why, when, and how. Anesth Analg 2005;101:481.
The national epidemic of obesity poses particular problems for
surgery and anesthesia. The body mass index (BMI), the ratio of
weight (kg)/height (meters)2, gives an idea of
the degree of obesity. Normal BMI is about 21.6 kg/m2,
overweight is 25–30 kg/m2, obese is 30–35
kg/m2, and extreme obesity is more than 35 kg/m2.
Extreme obesity patients have a variety of perioperative issues
and should be evaluated in a PAC. Particular attention should include
the upper airway and evaluation of cardiovascular, respiratory, metabolic,
and gastrointestinal systems. Abnormal BMI patients have cardiovascular
issues with venous access, hypertension, cardiomegaly, decreased
left ventricular function, and cor pulmonale, and they have twice
the incidence of ischemic heart disease than patients at normal
weight. Extreme obesity is associated with significant pulmonary
problems, including restrictive lung volumes, obstructive sleep
apnea, hypoxemia, increased Paco2, increased
hematocrit, and right heart failure. The extremely obese patient’s airway
is often difficult to maintain with mask ventilation secondary to
decreased neck mobility and adiposity and requires careful preoperative
evaluation. Almost all the major endocrine problems with extreme
obesity involve the effects of diabetes mellitus and require preoperative
assessment of glycemic control. Obesity also leads to abnormal fatty deposits
in the liver that cause increased metabolism of inhalation anesthetics. Morbidly
obese patients may have a higher risk of gastric aspiration and development
of aspiration pneumonia. Finally, postoperative pain management must
The most common metabolic abnormality is diabetes mellitus, and
its presence should cause a high index of suspicion for cardiac
problems. Patients on insulin therapy are at higher risk for cardiac morbidity
and mortality, including myocardial infarction and heart failure.
Glucose control may be very difficult to maintain in the perioperative
period, and preoperative assessment of control should always be
ascertained through history or laboratory testing. Recent studies
show that moderately tight glucose control in the perioperative
period is beneficial. Anesthesia providers are responsible for glucose
control during the procedure, and the surgical service is typically
responsible for this care in the postoperative period.
van den Berghe G et al: Intensive insulin therapy
in the critically ill patients. NEJM 2001;345;1359.
on Low Molecular Weight Heparin (LMWH)
Patients taking LMWH for deep venous thrombosis prophylaxis present
an unusual problem for both surgeon and anesthesiologist. The current
guidelines dictate that unless absolutely indicated, neuraxial anesthesia
(spinal, epidural) should not be performed unless LMWH has been
stopped for at least 12 hours and preferably 24 hours. That means that
a substitute anticoagulant should be initiated if neuraxial anesthesia
is to be done, or this approach is avoided.
Acute renal failure (ARF) occurs in approximately 1–5% of
all hospitalized patients and is responsible for increased length
of stay and mortality. The preoperative visit can help to identify
patient risk factors for ARF in those with previously normal renal
function undergoing noncardiac surgery. The perioperative onset of
ARF in patients with previously normal renal function is associated
with increased postoperative mortality, especially significant within
1 year postsurgery. BMI higher than 32 kg/m2,
age, emergency surgery, liver disease, high-risk surgery (intrathoracic,
intraperitoneal, suprainguinal vascular, large blood loss), peripheral
vascular occlusive disease, and chronic obstructive pulmonary disease
necessitating chronic bronchodilator therapy place patients at increased
risk for perioperative renal impairment.
Kheterpal S et al: Predictors of postoperative
acute renal failure after noncardiac surgery in patients with previously
normal renal function. Anesthesiology 2007;107:892.
The use of preoperative medications is hampered by the fact that
most patients are not in the medical facility until the day of surgery.
Most premedications now consist of an anxiolytic agent (eg, midazolam)
and an opiate (eg, fentanyl) given in the immediate preanesthesia
period. These premedications are often given because patients have
a preconceived notion that they need something to relax. Alternatively,
a thorough explanation of what the patient can expect in terms of surgery
and anesthesia has a significant calming effect comparable to that
of medications given to relieve anxiety. Administration of premedication
to prevent pulmonary aspiration syndrome is often considered with
the use of agents that increase gastric pH (H2 blockers,
proton pump inhibitors, antacids) or agents that lower gastric volume. Occasionally,
the use of drugs that stimulate gastric emptying (metoclopramide)
is considered. However, metoclopramide has significant neuropsychiatric
side effects, and its use should be limited.
Many institutions and practices obtain a signed informed consent
from patients for anesthesia, while other institutions include the
anesthesia consent in the surgical consent. Regardless of the particular
facility requirements, the anesthesiologist should write a note
in the patient chart indicating that the patient has been informed
of the issues surrounding anesthesia and understands the risks and
complications as described. The informed consent for anesthesia
should include a discussion of what to expect from the administration
of anesthesia and possible adverse effects and risks. A number of
issues should be discussed routinely, including timing of surgery,
premedication, risks of dental injury, cardiac risks, sequence of
events prior to anesthesia induction, awakening from anesthesia,
presence of catheters, duration of time in the PACU, anticipated
return to a hospital bed or discharge, postoperative pain management,
and the likelihood of nausea and vomiting. Patients may have questions concerning
perioperative awareness. Rather than cause undue worry, clinical
judgment should dictate how detailed a description of each of these
issues should be for each patient.
Considerations in choosing an anesthetic technique include the
planned surgical procedure, positioning requirements, patient preferences,
surgeon preferences, the urgency of the operation, postoperative
pain management, and potential for admission to a critical care unit.
Some procedures (eg, thoracotomy) cannot be performed under a regional anesthetic
or neuraxial blockade and necessitate a general anesthetic. Other procedures
(eg, extremity surgery) can be performed under regional, neuraxial, or
general anesthesia. Sometimes a combination of an epidural and a
general anesthetic may be chosen with continuation of the epidural
for postoperative pain management. Emergency surgery for patients
with a full stomach may necessitate a rapid-sequence general anesthetic to
protect from pulmonary aspiration. Regional anesthesia may provide
anesthesia for hip surgery but may not provide much in the way of
patient comfort because of the position requirements of a fracture
table. Patient age and preference must also be included in the decision
of choice of anesthetic technique. However, some regional anesthesia
may be contraindicated for patients with the peripheral neuropathy
of diabetes. Notation of the proposed type of anesthesia must be
entered into record of the preanesthesia evaluation.
and Operating Room
The nurse, surgeon, and anesthesiologist have many tasks to perform,
starting in the holding area before the surgery can begin. The nurse
checks the patient in and records vital signs, checks for a signed
consent, and starts an intravenous line if needed. The surgeon should confirm
and mark the site of surgery. The anesthesiologist should confirm
the preoperative evaluation and type of anesthetic selected.
In July 2004, the Joint Commission on the Accreditation of Healthcare
Organizations (JCAHO) instituted a patient safety mandate known
as the Universal Protocol for Preventing Wrong Site, Wrong Procedure,
Wrong Person Surgery. All members of the care team must be familiar
with and always participate in and perform the following three steps
of this Universal Protocol.
- Step 1:Initial verification of the intended patient, procedure, and
site of the procedure. This step begins at the time the procedure
is scheduled and again at the time of admission into the medical
facility, anytime care responsibility is transferred to another
caregiver, and before the patient leaves the preoperative area for
the operating room.
- Step 2:Marking the operative site. An unambiguous mark must
be made using a marker that is sufficiently permanent to be visible
after surgical prep and draping on or near the intended surgical
incision site. This mark should not be an X, as in “X marks the
spot,” but rather a word or line representing the proposed
incision. This mark must be made by the surgeon performing the procedure.
If possible, the patient should participate when the site is marked.
- Step 3:The time out immediately before starting the procedure.
A time out must be conducted in the location where the surgical
procedure will be done, and all members of the care team—surgeon,
nurses, anesthesiologists—must actively participate
in verification of correct patient identity, correct side and site
of surgery, agreement on the scheduled procedure, and assurance
that all of the necessary implants and special equipment are immediately
available. This time out must take place before incision. JCAHO
requires that the time out be documented in the medical record.
The anesthesiologist must check the equipment in the operating
room before helping to transport the patient. Once in the operating
room, the patient is transferred to the operating table with the
assistance of the nurses and anesthesiologist. It is standard anesthesia
practice to apply monitors to measure arterial blood pressure (a-line,
blood pressure cuff), heart rate, oxygenation (pulse oximeter),
and ventilation (capnography) before induction of anesthesia (Table 11–5).
Table 11–5. Standards for Basic Anesthesia Monitoring. |Favorite Table|Download (.pdf)
Table 11–5. Standards for Basic Anesthesia Monitoring.
|Oxygenation: ensure patient concentration
in inspired gas and blood during all anesthetics|
- Oxygen analyzer: part of anesthesia machine
oximeter: continuously audible variable pitch pulse tone
|Ventilation: Ensure adequate patient ventilation||Capnography: continuous monitoring for the
presence of end-tidal CO2|
|Circulation: Ensure adequacy of patient
- EKG: Continuously displayed from the beginning
until leaving the room
- Arterial blood pressure monitor: measured
at least every 5 minutes
- Measurement of patient heart rate: usually
from EKG or pulse oximeter
|Temperature: Aid in maintenance of appropriate
patient temperature||Oral, skin, nasal, or bladder temperature probe|
The anesthesiologist must be certain that a surgeon is present
in the room before beginning induction. The final time out should
then be performed, confirming site, patient, procedure, and surgical
Patients must be preoxygenated before induction of a general
anesthetic. General anesthesia is commonly induced by administration
of intravenous drugs (eg, propofol or thiopental) and, in cases
when cardiovascular status is compromised, etomidate or ketamine.
Patients receiving propofol may complain of discomfort at the IV
sites, and patients receiving etomidate may have some athetoid movements
that appear seizurelike. Almost all anesthetics are preceded by
the administration of an opiate (eg, fentanyl) in a dose that is
not intended to induce an anesthetic but that helps reduce the amount
of induction agent. Most general anesthetics then include a muscle
relaxant to facilitate endotracheal intubation. Tracheal intubation
is almost always performed during general anesthesia and is especially important
for patients presenting for emergent surgery with presumed full
stomach or when positive pressure ventilation is required. The laryngeal
mask airway (LMA) can also be used to maintain a patent airway.
To minimize the time that the trachea is unprotected, a rapid-sequence
induction of anesthesia using rapid administration of induction
agent and rapid-acting muscle relaxant (eg, succinylcholine) can
be utilized. The “crash induction” is a modification
of this rapid-sequence technique with the application of cricoid pressure
by a caregiver other than the inducing anesthesia personnel.
General anesthesia may also be induced by mask using an inhalation
anesthetic (eg, isoflurane or sevoflurane). This method is commonly
used for children. Once adequate depth of anesthesia is assured,
a muscle relaxant may be administered to help facilitate endotracheal
intubation. Inhalation induction takes longer than rapid-sequence
induction, and the airway may be unprotected for a longer time.
A combination of inhalation agent and intravenous agent can also
be used to induce general anesthesia.
Once an adequate depth of anesthesia and adequate muscle relaxation
is attained, the trachea is intubated. Ease of endotracheal intubation
can usually be predicted from the careful preoperative airway evaluation. However, the anesthesiologist occasionally
encounters an unexpected difficult intubation and additional maneuvers
may be necessary: these can include cricoid manipulation, adjustment
of the patient’s head position, or use of a long, stiff
catheter (eg, a bougie) or a fiberoptic bronchoscope. The American
Society of Anesthesiologists provides an algorithm for the management
of the difficult airway. If another provider is placing cricoid pressure,
the anesthesiologist must directly state what maneuver would be the
most helpful. If the airway cannot be secured after multiple attempts,
patients can be awakened and a decision made to proceed with an
awake fiberoptic intubation or to cancel the anesthetic until further
workup can be performed. The most serious complication of endotracheal
intubation, and the most common cause of serious anesthesia morbidity and
mortality, is the failure to secure the airway. Other common complications
are dental injuries, soft tissue injury to the lips, hypertension
and tachycardia, and laryngospasm on extubation.
Following anesthetic induction, the patient must be properly
positioned for the procedure. It is the responsibility of both surgeon
and anesthesiologist to assure that the patient is positioned to
avoid physical or physiologic complications. The American Society
of Anesthesiologists’ closed claims study notes that nerve
damage from malpositioning during surgery is the second most common anesthetic
complication. Careful attention must be paid to adequately protect
all potential pressure and vulnerable areas such as elbows, knees,
heels, and eyes. The ulnar nerve is particularly susceptible to
injury, as is the brachial plexus when patient’s arms are
abducted too far. Hemodynamics may also be compromised by position
changes that may result in decreased venous return and resultant hypotension.
American Society of Anesthesiologists: Practice
guidelines for management of the difficult airway: an updated report
by the American Society of Anesthesiologists Task Force on Management
of the Difficult Airway. Anesthesiology 2003;98:1269.
Cheney FW et al: Nerve injury associated with anesthesia: a
closed claims study. Anesthesiology 1999;90:1062.
of General Anesthesia
Once the airway is safely secured, anesthesiologists commonly
maintain the anesthetic with a combination of an inhalation agent,
nitrous oxide, opiate, and muscle relaxant. This “balanced
anesthetic” allows for titration of agents to maintain
the requirements of anesthesia: analgesia, amnesia (unconsciousness), skeletal
muscle relaxation, and control of the hemodynamic responses to surgical stimulation.
Drugs with specific pharmacologic profiles are chosen to help satisfy the
anesthetic requirements. Analgesia is provided by opiates and inhalational agents;
amnesia is provided by benzodiazepines, nitrous oxide, and inhalation agents;
and muscle relaxation is provided by neuromuscular-blocking drugs, inhaled
agents, or local anesthetics. The provision of the right amount
of muscle relaxation to facilitate the procedure but not too much
to obscure a clinical sign of anesthetic depth or to result in prolonged relaxation
postoperatively presents a challenge to the anesthesiologist. A peripheral
nerve stimulator can monitor muscle relaxation such that the relaxant is
reversible at the end of the case to allow for safe extubation.
Many operations require no general anesthetic. These include
almost any procedure done below the waist, on lower abdomen, and
on the upper extremities. Spinal or epidural anesthesia provide
excellent muscle relaxation, profound analgesia, and avoidance of
airway manipulation, and allows the patient to be conscious. Spinal
or epidural anesthesia have additional advantages: decreased blood loss
during orthopedic procedures, fewer thrombotic complications, less
pulmonary compromise, maintenance of vasodilatation for postoperative
vascular surgeries, earlier hospital discharge, and avoidance of
immune response compromise.
Most spinal anesthetics are performed in either the lateral position
or with the patient sitting on the operating table. Following sterile
prep and local skin anesthetic, a small 25-27 gauge spinal needle is
introduced in the lower lumbar spine, and the subdural space is
identified by the presence of cerebrospinal fluid (CSF). Depending
on the planned length of surgery, either lidocaine or bupivacaine
(with or without epinephrine or an opiate) is injected. Lidocaine
spinal anesthesia provides at most 2 hours of anesthesia, while
bupivacaine provides up to 5 hours of anesthesia. However, due to
patient discomfort from tourniquet break-through pain, the use of
orthopedic tourniquets limits the usefulness of spinals no matter
which local anesthetic is used to no more than 2 hours. Once the
local agent is injected, patients are placed in the supine position
for 5–10 minutes to allow for proper spread of the local
anesthetic. During this time, blood pressure and heart rate are
monitored; both hypotension and bradycardia can be induced by a
sympathectomy due to the cephalad spread of the local. During this
5–10 minute period, patient movement should be limited.
Once the block has stabilized, the surgical preparation and positioning
can proceed. The anesthesiologist monitors the patient in the same
manner as for general anesthesia and administers sedation as needed.
Other than expected hemodynamic changes, the most common complication of
spinal anesthesia is postspinal headaches. The incidence is very
low when smaller gauge spinal needles are used and are more common
in young women. The spinal headache is almost always positional
and abates when the patient is recumbent. Severe headaches can result in
diplopia because of stretching of the 6th cranial nerve as the brain
sinks from loss of CSF. Patients usually complain of the headache
a day or two following the operation. Conservative treatment is
the maintenance of adequate hydration, remaining recumbent, and
an analgesic such as acetaminophen. Severe headache may require
a “blood patch” to plug the leak of CSF and is
performed by an anesthesiologist.
Epidural anesthesia has several distinct differences from spinal
anesthesia. The epidural space is between the ligamentum flavum
and the dural structures; in placing an epidural, the subdural space is
not entered, and so no CSF leak is created with the potential for
a spinal headache. The epidural anesthetic may be continued by insertion
of a small catheter into the epidural space. Additional local anesthetic
can be added to move the block to higher spinal levels or to maintain
the selected level of anesthesia. This continuous epidural technique
can be used for postoperative pain control. The catheter can be
placed at spinal levels in the midthoracic region for thoracotomy
or lower thoracic or lumbar region for abdominal operations or lower extremity
procedures. Epidural anesthesia requires the administration of high volumes
of local anesthetics. There is the potential for intravascular injection with
resultant cardiovascular compromise or high block. There is also
the potential for misplacement of the catheter or epidural needle
in the subarachnoid space. Instillation of the larger volumes of
local in the subarachnoid space can result in a total spinal or
high block with resultant cardiovascular collapse. Therefore, small
test doses of local anesthetic are administered to evaluate for
signs of intravenous injection or high block. Another potential
disadvantage of epidural anesthesia is that the onset is much slower
than spinal anesthesia. The same hemodynamic changes observed with
epidural can occur with spinals.
A common complication of both spinal and epidural anesthesia
is prolonged blockade of parasympathetic fibers that innervate the
bladder with resultant urinary retention and the need for a urinary
True regional anesthesia is useful for procedures on the extremities.
Useful anesthesia of the upper extremity can be obtained by blockade
of the brachial plexus using an interscalene approach, a supraclavicular
approach, or an axillary approach. Lower extremity surgery may be
performed utilizing blockade of the lumbar plexus and its major
branches: femoral nerve, sciatic nerve, lateral femoral cutaneous
nerve, obturator nerve, and popliteal nerve. In some instances,
a catheter can be placed near the nerve or plexus to allow for continuous
blockade and postoperative pain control. The usefulness of these
blocks for extremity surgery is limited in time by the use of tourniquets
if the patient is to remain awake during the procedure. These blocks
are very useful if avoidance of a general anesthetic is desired.
Additional advantages of peripheral nerve blocks include earlier
discharge from recovery areas and return to home, lack of administration
of large doses of opiates, less nausea and vomiting, no instrumentation of
patient airway, and earlier ambulation. Intraoperative sedation
may be provided, and the anesthesiologist monitors the patient in
the standard manner.
MAC was previously termed local anesthesia with standby. The “standby” is
an anesthesia caregiver who monitors the patient’s status
while the surgeon performs a procedure under local anesthesia. The
anesthesiologist can also provide sedation and analgesia as needed
for the patient. This type of anesthesia is usually requested by
the surgeon for patients who may be especially frail in health; it
provides the option to convert to a general anesthetic if necessary.
At the end of the procedure, most often patients who have been
intubated for the surgery have their muscle relaxation reversed
and the anesthetic depth decreased to allow them to return to consciousness.
Once the return of muscle function has been assured and the patient
is able to respond to commands, the endotracheal tube can be removed
and the patient closely observed to ensure adequate ventilation.
Patients are then transferred to a stretcher and transported to
the PACU, accompanied by a member of the anesthesia care team who
monitors the patient’s condition during transport. Many
institutions require that a member of the surgical team also accompany
the patient to the PACU along with the anesthesiologist. Some critically
ill patients are transported directly to the intensive care unit
(ICU), still intubated, sedated, and ventilated.
The PACU, most commonly known as the recovery room, is where
most patients are transferred after surgery. The PACU is the designated
area in which patients receive postanesthesia monitoring of vital
signs as well as the beginning of the nursing care for their surgical
recovery. It is the standard of the American Society of Anesthesiologists that
all patients, regardless of the type of anesthesia, receive appropriate
postanesthesia care, either in a PACU or an equivalent area such
as a critical care unit. An exception to this standard can only
be made by the anesthesiologist responsible for the patient’s
care. Once in the PACU, a verbal report is provided to the responsible
PACU nurse by a member of the anesthesia care team who is familiar
with and who accompanied the patient during transport. The surgeon
can also give a report as to the surgical issues that may impact
on the patient’s recovery.
The PACU is equipped with essentially the same monitors as the
operating room and with the drugs and equipment needed for emergency
resuscitation. The PACU is a specialized, short-stay ICU. PACUs
are staffed with specially trained nurses to monitor patients who
are recovering from the anesthetic. Patients are continually monitored
in the PACU for approximately 1 hour or until they fulfill specific
objective criteria. Discharge from the PACU requires the clinical
judgment of the PACU team. Particular attention is focused on the
monitoring of oxygenation, ventilation, circulation, level of consciousness, and
Current literature supports the use of discharge scoring systems
(eg, the Aldrete score) describing objective criteria that must
be fulfilled before the patient can be discharged from the PACU.
These criteria include quantitative analysis of patient’s
ability to move extremities in response to verbal commands, adequacy
of ventilation (pulse oximetry) and circulation (stable vital signs)
and level of consciousness, and pain control. After outpatient surgery,
patients must have an adult to escort them home. Most institutions
have policies requiring that anesthesiologists, in conjunction with the
PACU nursing team, discharge patients from PACU.
Aldrete JA, Kroulik D. A postanesthetic recovery
score. Anesth Analg 1970;49:924.
Awad JT, Chung F. Factors affecting recovery and discharge following
ambulatory surgery. Can J Anaesth 2006;53:858.