Clinical Anesthesia Procedures of the Massachusetts General Hospital

226 Pages·2005·2.9 MB·English

Clinical Anesthesia Procedures of the Massachusetts General Hospital 6th edition (June 15, 2002): by William E. Hurford (Editor), Michael T. Bailin (Editor), J.
Kenneth Davison (Editor), Kenneth L. Haspel (Editor), Carl Rosow (Editor), Susan A. Vassallo (Editor), Massachusetts General Hospital Dept. of Anesthesia and
Critical Care, Nicholas E. Awde By Lippincott Williams & Wilkins Publishers
By OkDoKeY
Clinical Anesthesia Procedures of the Massachusetts General Hospital
Contents
Editors
Preface
I. Evaluating the Patient Before Anesthesia
1. Evaluating the Patient Before Anesthesia
Mary Kraft and Richard A. Wiklund
2. Specific Considerations with Cardiac Disease
James G. Cain
3. Specific Considerations with Pulmonary Disease
Kevin C. Dennehy and Kenneth E. Shepherd
4. Specific Considerations with Renal Disease
Adam Sapirstein
5. Specific Considerations with Liver Disease
Robert Peloquin and Michael T. Bailin
6. Specific Considerations with Endocrine Disease
Robert A. Peterfreund and Stephanie L. Lee
7. Infectious Diseases and Infection Control in Anesthesia
Judith Hellman
II. Administration of Anesthesia
8. Safety in Anesthesia
Jeffrey B. Cooper
9. The Anesthesia Machine
Jane C. Ballantyne
10. Monitoring
John L. Walsh and Barry M. Stowe
11. Intravenous and Inhalation Anesthetics
Mark Dershwitz
12. Neuromuscular Blockade
Jason A. Campagna and Peter F. Dunn
13. Airway Evaluation and Management
Harish Lecamwasam and Peter F. Dunn
14. Administration of General Anesthesia
Stuart A. Forman
15. Local Anesthetics
Tania Haddad and Jeannie Min
16. Spinal, Epidural, and Caudal Anesthesia
Shobana Chandrasekhar and May C. M. Pian-Smith
17. Regional Anesthesia
James B. Mayfield and Margaret Gargarian
18. Intraanesthetic Problems
Keith H. Baker and Douglas E. Raines
19. Perioperative Hemodynamic Control
Vilma E. Ortiz and Robert R. Morgan, Jr.
20. Anesthesia for Abdominal Surgery
Jean Kwo and John J. A. Marota
21. Anesthesia for Thoracic Surgery
Paul H. Alfille
22. Anesthesia for Vascular Surgery
Edward Bittner and Peter F. Dunn
23. Anesthesia for Cardiac Surgery
Scott C. Streckenbach and Derrick B. Willsey
24. Anesthesia for Neurosurgery
Wolfgang Steudel and Michele Szabo
25. Anesthesia for Head and Neck Surgery
Avine Lydon and Martin Andrew Acquadro
26. Anesthesia for the Elderly and for Urologic Surgery
Harvey C. Shew and William Kimball
27. Anesthesia for Surgical Emergencies in the Neonate
Jesse D. Roberts, Jr., Jonathan H. Cronin, and Maria M. Zestos
28. Anesthesia for Pediatric Surgery
Susan A. Vassallo
29. Anesthesia for Obstetrics and Gynecology
Jeannie Min and Tania Haddad
30. Ambulatory Anesthesia
James B. Mayfield
31. Anesthesia Outside the Operating Room
William E. Hurford and Susan A. Vassallo
32. Anesthesia for Trauma and Burns
Christopher Carter and Keith H. Baker
33. Transfusion Therapy
Rae M. Allain
III. Perioperative Issues
34. The Postanesthesia Care Unit
Edward E. George and Luca M. Bigatello
35. Perioperative Respiratory Failure
Edward E. George and Luca M. Bigatello
36. Adult, Pediatric, and Newborn Resuscitation
Richard M. Pino
37. Pain
Joshua Bloomstone and David Borsook
38. Complementary and Alternative Medicine
Margaret Gargarian and P. Grace Harrell
39. Ethical and End-of-Life Issues
William E. Hurford and Rae M. Allain
Appendix
I. Supplementary Drug Information
II. Normal Laboratory Values for Blood
Department of Anesthesia and Critical Care
Massachusetts General Hospital
Harvard Medical School
Senior Editor
William E. Hurford, M.D.
Associate Editors
Michael T. Bailin, M.D.
J. Kenneth Davison, M.D.
Kenneth L. Haspel, M.D.
Carl Rosow, M.D.
Susan A. Vassallo, M.D.
Preface
The sixth edition of Clinical Anesthesia Procedures of the Massachusetts General Hospital was written by residents, fellows, staff, and alumni of the Department of
Anesthesia and Critical Care at the Massachusetts General Hospital. This manual continues to emphasize the clinical fundamentals involved in the safe
administration of anesthesia, perioperative care, and pain management. The suggestions reflect current clinical practices at our hospital; other methods may be
equally effective.
This handbook complements readings in textbooks and journals and assumes some prior knowledge of anesthesia and critical care. It is designed to be an accessible
and accurate source of information for practicing anesthesiologists, anesthesia residents, nurse anesthetists, medical students, medical and surgical residents,
nurses, respiratory therapists, and other health care professionals involved in perioperative care. The manual is not intended to replace experienced clinical teaching
or substitute for detailed study. Each chapter contains a reading list for those who desire additional information on a topic.
Clinical Anesthesia Procedures of the Massachusetts General Hospital has been repetitively edited, revised, and relied upon as a clinical reference for over twenty
years. Over one hundred and fifty individuals have contributed to the manual during this time. While constantly adding new information, each new edition is built upon
the foundation of previous versions. Source material from prior editions has been included verbatim when appropriate. We acknowledge the guidance and support
given to early editions by Richard J. Kitz, M.D. and the continuing support of Warren M. Zapol, M.D. We thank Ms. Rita M. Prevoznik for administrative and editorial
assistance. The integral contributions of the editors and authors of earlier editions of this handbook are gratefully acknowledged below:
Editors of Previous Editions: First Edition (1978): Philip W. Lebowitz, John L. Clark, Daniel F. Dedrick, James R. Zaidan, Robert K. Crone; Second Edition (1982):
Philip W. Lebowitz, Leslie A. Newberg, Michael T. Gilette; Third Edition (1988): Leonard L. Firestone, Philip W. Lebowitz, Charles E. Cook; Fourth Edition (1993): J.
Kenneth Davison, William F. Eckhardt, III, Deniz A. Perese; Fifth Edition (1997): William E. Hurford, Michael T. Bailin, J. Kenneth Davison, Kenneth L. Haspel, Carl
Rosow.
Contributors to Previous Editions: Martin Andrew Acquadro, Shahriar Alikhani, Paul H. Alfille, James K. Alifimoff, Rae M. Allain, Robert P. Antonio, Michael Bailin,
Keith H. Baker, Jane C. Ballantyne, Paul Barach, James M. Barton, Salvatore J. Basta, Wayne H. Bellows, Clifferd Bierman, Luca M. Bigatello, Janice Bitetti, Kenneth
Blazier, Joshua Bloomstone, David Borsook, Ronald J. Botelho, Jeffrey B. Brand, James G. Cain, William H. Campbell, Bryn T. Carpenter, Daniel B. Carr, Christopher
Carter, Bobby Su-Pen Chang, John L. Clark, David Clement, Lydia Conlay, Charles E. Cook, Jeffrey B. Cooper, Benjamin G. Covino, Garland A. Cowan, Robert K.
Crone, Marianna Crowley, Deborah J. Culley, Alberto deArmendi, Daniel F. Dedrick, Mark Dershwitz, John V. Donlon, Richard P. Dutton, William Dylewsky, Clifton W.
Emerson, Paul L. Epstein, Leonard L. Firestone, Susan Firestone, Stuart A. Forman, Robert Gaiser, Margaret Gargarian, Clifford M. Gevirtz, Noel Gibney, Michael T.
Gilette, Kenneth Giuffre, Randall S. Glidden, Takahisa Goto, Heath Gulden, Douglas M. Hansell, Jane Hardiman, Timothy J. Herbst, J. Fredrik Hesselvik, Randall S.
Hickle, Thomas L. Higgins, Thomas Hill, Allen J. Hinkle, Vincent L. Hoellerich, Robert Hunsaker, William E. Hurford, Mansoor Husain, Gloria Hwang, D. Jay Iaconetti,
Charles C. Jeffrey, Andrew A. Jeon, Lisa A. Keglovitz, William Kimball, David Kliewer, David Koehler, W. Andrew Kofke, James L. Konigsberg, Peter G. Kovatsis,
Mary Kraft, William B. Latta, Charles E. Laurito, Philip W. Lebowitz, Betty Lee, Stephanie Lee, Paul Lennon, Rebecca Leong, David Lerdahl, Jerrold H. Levy, Michael
C. Long, Thomas J. Long, James C. Loomis, John J. Marota, Piotr Michalowski, Thomas A. Mickler, Richard A. Miller, Alex Mills, Rowan Molnar, Holly Ann H. Morgan,
Brian P. Murray, Michael Natale, Leslie A. Newberg, Ronald S. Newbower, Phillippa Newfield, Ervant Nishanian, Daniel L. Nozik, Conor O'Neill, Vilma E. Ortiz,
Charles W. Otto, Onofrio Patafio, Blake M. Paterson, John Pawlowski, Robert A. Peterfreund, May C.M. Pian-Smith, Michael Pilla, Richard M. Pino, Marie Csete
Prager, Douglas E. Raines, Frederic M. Ramsey, James T. Roberts, Jesse D. Roberts, Jr., Peter Rosenbaum, Carl Rosow, Fred A. Rotenberg, Peter Rothstein, Steve
Rotter, Barbara A. Ryan, Adam Sapirstein, William P. Schecter, Larry B. Scott, Kenneth E. Shepherd, George Shorten, Stephen Small, Aileen Starnbach, David J.
Stone, Scott C. Streckenbach, Susan L. Streitz, Veronica C. Swanson, Bobbie-Jean Sweitzer, Michele Szabo, Alfonso A. Tagliavia, Robert E. Tainsh, Frank A.
Takacs, Gary D. Thal, Steven Thorup, I. David Todres, Susan A. Vassallo, John S. Wadlington, Samuel Wald, John L. Walsh, James P. Welch, Norman E. Wilson,
Julianne S. Wimberly, Lisa Wollman, James R. Zaidan, and Maria M. Zestos.
W. E. Hurford, M.D.
1 Evaluating the Patient Before Anesthesia
Clinical Anesthesia Procedures of the Massachusetts General Hospital
1
Evaluating the Patient Before Anesthesia
Mary Kraft and Richard A. Wiklund
Overview
History
The anesthetist
Coexisting medical illnesses
Medications
Allergies and drug reactions
Anesthetic history
Family history
Social history
Review of systems
Physical examination
The physical examination
Laboratory studiesRoutine laboratory screening tests are rarely useful
Recent hematocrit/hemoglobin level
Serum chemistry studies
An electrocardiogram (ECG)
Chest radiography
Anesthesiologist–patient relationship
The perioperative period is emotionally stressful
Informed consent
Anesthesia consultant's note
A concise legible statement
Relevant positive and negative findings
A problem list
An overall impression
The anesthesia plan
Guidelines for NPO status
Premedication
Goals
Sedatives
Opioids
Anticholinergics
Guidelines for prophylaxis for pulmonary aspiration
Suggested Reading
I. Overview
The preanesthetic evaluation has specific objectives, which include establishing a doctor–patient relationship, becoming familiar with the surgical illness and
coexisting medical conditions, developing a management strategy for perioperative anesthetic care, and obtaining informed consent for the anesthetic plan. The
consultation is detailed in the patient's record and concludes with the anesthetic options and their attendant risks and benefits. The overall goals of the
preoperative assessment are to reduce perioperative morbidity and mortality and allay patient anxiety.
II. History
Relevant information is obtained by a chart review followed by the patient interview. Knowledge of the patient's history when beginning the interview is
reassuring to the anxious patient. When the medical record is not available, the history obtained from the patient may be supplemented by direct discussion with
the medical and surgical staff. Although patient age and American Society of Anesthesiologists (ASA) Physical Status Classification are more accurate
predictors of adverse outcomes, knowledge of patients' activities of daily living, including maximum activity level, may help predict their overall outcome in the
perioperative period.
A. The anesthetist should learn the symptoms of the present surgical illness, the diagnostic studies performed, presumptive diagnosis, initial treatment, and
responses. Vital signs should be reviewed and fluid balance estimated.
B. Coexisting medical illnesses may complicate the surgical and anesthetic course. These should be evaluated in a systematic “organ systems” approach
with an emphasis on recent changes in symptoms, signs, and treatment (see Chapter 2, Chapter 3, Chapter 4, Chapter 5, Chapter 6, and Chapter 7). In
certain circumstances, preoperative specialty consultation may be advisable. Such consults are most valuable when answering specific questions regarding
the interpretation of unusual laboratory tests, unfamiliar drug therapies, or changes from the patient's baseline status. Consultants should not be asked for a
general “clearance” for anesthesia because this is the specific responsibility of the anesthesiologist.
C. Medications used to treat present or coexisting illnesses, their dosages, and schedules must be ascertained. Of special importance are antihypertensive,
antianginal, antiarrhythmic, anticoagulant, anticonvulsant, and specific endocrine (e.g., insulin) medications. The decision to continue medications during the
preanesthetic period depends on the severity of the underlying illness, the potential consequences of discontinuing treatment, the medication's half-life, and
the likelihood of deleterious interactions with proposed anesthetic agents. As a general rule, medications can be continued up to the time of surgery.
D. Allergies and drug reactions. Unusual, unexpected, or unpleasant reactions to perioperative medications and nonallergic adverse reactions, side effects,
and drug interactions are relatively common. True allergic reactions are relatively uncommon. The task of determining the exact nature of specific “reactions”
may be difficult. Therefore, it is important to obtain a careful description of the “allergic reaction” experience from the patient.
1. True allergic reactions. Any drug that (by direct observation, chart documentation, or description by the patient) leads to skin manifestations (pruritus
with hives or flushing), facial or oral swelling, shortness of breath, choking, wheezing, or vascular collapse should be considered to have elicited a true
allergic reaction.
a. Antibiotics, especially sulfonamides, penicillins, and cephalosporin derivatives, are the most common allergens.
b. Known allergy to shellfish or seafood is important to document, because allergic cross-reactions with intravenous (IV) contrast dye and the
heparin-reversing agent protamine may occur. Known allergy to soybean oil and egg yolk components may preclude the safe use of some
preparations of propofol.
c. A history of “allergy” to halothane or succinylcholine (in either the patient or any close relative) warrants special attention, because this may
represent the occurrence of malignant hyperthermia, halothane hepatitis, or prolonged paralysis caused by an abnormal allele responsible for
production of plasma cholinesterase, an enzyme that metabolizes succinylcholine.
d. True allergy to the amide-type local anesthetics (e.g., lidocaine) is exceedingly rare, although a syncopal episode, tachycardia, or palpitations in
the dentist's chair or before starting an IV with injection of local anesthetic may be falsely labeled as allergic. Ester-type local anesthetics (e.g.,
procaine) can produce anaphylaxis (see Chapter 15).
2. Adverse reactions and side effects. Many perioperative medications can produce memorable unpleasant side effects (e.g., nausea, vomiting, and
pruritus after narcotic administration) in a conscious patient.
3. Certain rare but important drug interactions must be anticipated because of their life-threatening nature. For example, thiopental may precipitate a
fatal episode of acute intermittent porphyria, and meperidine may produce a hypertensive crisis when administered to patients treated with monoamine
oxidase inhibitors. Newer antiparkinsonian drugs (anticholinesterases) may prolong paralysis after succinylcholine administration.
E. Anesthetic history
1. Old anesthesia records should be reviewed for the following information:
a. Response to sedative/analgesic premedications and anesthetic agents.
b. Ease of mask ventilation, direct laryngoscopy, and the size and type of laryngoscope blade and endotracheal tube used.
c. Vascular access and invasive monitoring used and difficulties encountered.
d. Perianesthetic complications such as adverse drug reactions, cephalgia, intraoperative awareness, dental injury, protracted postoperative nausea and
vomiting, cardiorespiratory instability, postoperative myocardial infarction or congestive heart failure, unexpected admission to an intensive care unit
(ICU), and prolonged emergence or intubation.
2. Patients should be asked about prior anesthetics, including common complaints such as postoperative nausea and hoarseness and specific warnings
from previous anesthetists describing prior anesthetic problems.
F. Family history. A history of adverse anesthetic outcomes in family members should be evaluated. This history is perhaps best obtained with open-ended
questions, such as “Has anyone in your family experienced unusual or serious reactions to anesthesia?” Patients should be specifically asked about a family
history of malignant hyperthermia.
G. Social history
1. Smoking. A history of exercise intolerance or the presence of a productive cough or hemoptysis may indicate a need for further pulmonary evaluation or
treatment. Eliminating cigarette use for 2 to 4 weeks before elective surgery may reduce airway hyperreactivity and perioperative pulmonary
complications.
2. Drugs and alcohol. Although self-reporting of drug and alcohol intake typically underestimates actual use, it is a helpful starting point to define the drugs
used, routes of administration, frequency, and timing of most recent use. Stimulant abuse may lead to palpitations, angina, weight loss, and lowered
thresholds for serious arrhythmias and seizures. Acute alcohol intoxication will decrease anesthetic requirements and predispose to hypothermia and
hypoglycemia, whereas withdrawal from ethanol may precipitate severe hypertension, tremors, delirium, seizures, and may markedly increase
anesthetic requirements. The routine use of opioids and benzodiazepines may significantly increase the doses needed to induce and maintain
anesthesia or to provide adequate postoperative analgesia.
H. Review of systems. Acute or chronic lung disease, ischemic heart disease, hypertension, and gastroesophageal reflux are examples of commonly
encountered coexisting conditions that increase the risk of perioperative morbidity and mortality. A minimum review of systems should seek to elicit history of
the following:
1. A recent history of an upper respiratory infection, especially in children, which predisposes patients to pulmonary complications including
bronchospasm and laryngospasm during the induction of and emergence from general anesthesia.
2. Asthma, which may be accompanied by airway mucous plugging and acute bronchospasm after the induction of anesthesia or endotracheal intubation.
3. Preexisting coronary artery disease (CAD), which may predispose the patient to myocardial ischemia, ventricular dysfunction, or myocardial infarction
with the stress of surgery and anesthesia.
4. Diabetes, which may predispose the patient to silent ischemia, especially in those with autonomic nervous system dysfunction. Alterations of the
autonomic nervous system may also lead to gastroparesis and active reflux. In addition, endotracheal intubation may be difficult in some diabetic patients
because of arthritis of the temporomandibular joints and cervical spine, resulting from glycosylation of synovium.
5. Untreated hypertension, which is frequently associated with blood pressure lability during anesthesia. If associated with left ventricular hypertrophy,
hypertension leads to a higher incidence of postoperative complications (e.g., stroke, myocardial infarction). Diuretic therapy can produce hypovolemia
and electrolyte imbalances, especially in the elderly.
6. Hiatal hernia with esophageal reflux symptoms, which increases the risk of pulmonary aspiration and may alter the anesthetic plan (e.g., an awake
intubation or a “rapid sequence” induction may be chosen).
7. Likelihood of pregnancy and timing of last menses in women of childbearing age, because premedications and anesthetic agents may adversely
influence uteroplacental blood flow, act as teratogens, or lead to spontaneous abortion.
III. Physical examination
A. The physical examination should be thorough but focused. Special attention is directed toward evaluation of the airway, heart, lungs, and neurologic
examination. When regional anesthetic techniques are to be applied, detailed assessment of the extremities and back is necessary.
B. As a minimum, the physical examination should include the following:
1. Vital signs
a. Height and weight are useful in estimating drug dosages and determining volume requirements and the adequacy of perioperative urine output.
b. Blood pressure should be recorded in both arms and any disparity between upper extremities noted (significant differences may imply disease of the
thoracic aorta or its major branches). Postural signs should be checked in patients suspected of hypovolemia.
c. Resting pulse is noted for rhythm, perfusion (fullness), and rate. The pulse may be slow in patients receiving b-adrenergic blockade or rapid and
bounding in the patient with fever, aortic regurgitation, or sepsis. Anxious or dehydrated patients may have rapid weak pulses.
d. Respirations are observed for rate, depth, and pattern while at rest.
2. Head and neck. The details of a thorough head and neck examination are outlined in Chapter 13. During a basic preoperative examination, one should
a. Note the size of the oral opening as measured by finger breadths and the ability to visualize the posterior pharyngeal structures (Mallampati
classification).
b. Measure thyromental distance.
c. Document loose or chipped teeth, artificial crowns, dentures, and other dental appliances.
d. Note the range of cervical spine motion in flexion, extension, and rotation.
e. Document tracheal deviation, cervical masses, and carotid bruits.
3. Precordium. Auscultation of the heart may reveal murmurs, gallop rhythms, or a pericardial rub.
4. Lungs. Auscultation may reveal wheezing, rhonchi, or rales, which should be correlated with observation of the ease of breathing and use of accessory
muscles of respiration.
5. Abdomen. Any evidence of distention, masses, or ascites should be noted, because these might predispose to regurgitation or compromise ventilation.
6. Extremities. Muscle wasting and weakness should be documented, as well as general distal perfusion, clubbing, cyanosis, and cutaneous infection
(especially over sites of planned vascular cannulation or regional nerve block). Ecchymosis or unexplained injuries, especially in children, women, or
elderly patients, can be an indication of an abusive relationship.
7. Back. Note any deformity, bruising, or infection.
8. Neurologic examination. Document mental status, cranial nerve function, cognition, and peripheral sensorimotor function.
IV. Laboratory studiesRoutine laboratory screening tests are rarely useful. Laboratory tests should be selected based on the patient's medical condition and
the proposed surgical procedure. A brief review of current guidelines follows.
A. Recent hematocrit/hemoglobin level. There is no universally accepted minimum hematocrit level before anesthesia. Hematocrits in the 25% to 30% range
are well tolerated by otherwise healthy people but could result in ischemia in patients with CAD. Each case must be evaluated individually for the etiology
and duration of anemia. If there is no obvious explanation for anemia, a delay of surgery may be indicated. Healthy patients who are undergoing minimally
invasive procedures do not need routine hematocrit screen. A hematocrit screen is recommended for neonates up to 6 months of age, women over 50 years
of age, and men over 65 years of age.
B. Serum chemistry studies are ordered only when specifically indicated by the history and physical examination. For example, blood urea nitrogen and
creatinine levels are indicated for patients over 65 years of age or for those with chronic renal disease, diabetes, cardiovascular disease, intracranial
disease, hepatic disease, morbid obesity, or in patients using diuretics, digoxin, steroids, or aminoglycosides.
1. Hypokalemia is common in patients receiving diuretics and is usually readily corrected by preoperative oral potassium supplementation. Most often, mild
hypokalemia (2.8 to 3.5 mEq/L) should not preclude elective surgery. Efforts to rapidly correct hypokalemia with IV replacement therapy may lead to
arrhythmias and cardiac arrest. In the face of marked hypokalemia with arrhythmias, especially in the setting of digoxin use, a delay in surgery to allow
cautious correction is reasonable.
2. Platelet function may be assessed by a history of easy bruising, excessive bleeding from gums or minor cuts, and family history.
3. Coagulation studies are ordered only when clinically indicated (e.g., history of a bleeding diathesis, anticoagulant use, or serious systemic illness) or if
postoperative anticoagulation is planned.
C. An electrocardiogram (ECG) is advisable for men over 40 years of age and women over 50 years of age. Although the resting ECG is not a sensitive test
for occult myocardial ischemia, an abnormal ECG mandates correlation with history, physical examination, and prior ECGs and may require further workup
and consultation with a cardiologist before surgery.
D. Chest radiography should be performed only when clinically indicated (e.g., heavy smokers, the elderly, and patients with major organ system disease
including malignancy and symptomatic heart disease).
V. Anesthesiologist–patient relationship
A. The perioperative period is emotionally stressful for many patients who may have fears about surgery (e.g., cancer, physical disfigurement, postoperative
pain, and even death) and anesthesia (e.g., loss of control, fear of not waking up, waking up during surgery, postoperative nausea, confusion, pain,
paralysis, and headache). The anesthetist can alleviate many of these fears and foster trust by
1. Conducting an unhurried organized interview in which you convey to the patient that you are interested and understand his or her fears and concerns.
2. Reassuring the patient that you will see the patient in the operating room. If the physician performing the assessment will not be the anesthetizing
physician, the patient should be advised and reassured that their concerns and needs will be competently relayed and addressed.
3. Informing the patient of the events of the perioperative period, including:
a. The time after which the patient must have nothing to eat or drink (nothing by mouth [NPO]).
b. The estimated time of surgery.
c. The need for sedative premedications (see section VIII.B.) and whether the patient's daily medications should be continued as usual.
d. The need for autologous blood donation. This usually is indicated for only a limited number of surgical procedures such as total joint arthroplasty,
radical prostatectomy, and extensive spine surgery.
e. Management of aspirin and nonsteroidal anti-inflammatory drug (NSAID) therapy. Newer NSAIDs that inhibit the cyclooxygenase-2 enzyme do not
interfere with platelet function and do not need to be discontinued before surgery.
f. Tasks to occur on the day of surgery (e.g., placement of IV or arterial catheters, routine monitoring devices, epidural catheters) with reassurance that
supplemental IV sedation and analgesia will be provided as necessary during this period.
g. Postoperative recovery either in the postanesthesia care unit or ICU for closer observation.
h. Plans for postoperative pain control.
Note: The above discussion should be restricted to those endeavors specific to anesthesia; opinions regarding the surgical diagnosis, prognosis, and
issues of surgical technique should be conveyed by the surgeon.
B. Informed consent involves discussing the anesthetic plan, alternatives, and potential complications in terms understandable to the lay person. It is strongly
preferable that this discussion is conducted and any forms written in the patient's native language.
1. Certain aspects of anesthetic management are outside the realm of common experience and must be explicitly defined and discussed beforehand.
Examples include endotracheal intubation, mechanical ventilation, invasive hemodynamic monitoring, regional anesthesia techniques, blood product
transfusion, and postoperative ICU care.
2. Alternatives to the suggested management plan should be presented, because they may become necessary if the planned procedure fails or if there is a
change in clinical circumstances.
3. Risks associated with anesthesia-related procedures should be disclosed in a way that a reasonable person would find helpful in making a decision.
In general, disclosure applies to complications that occur with a relatively high frequency, not to all remotely possible risks. The anesthetist should
familiarize the patient with the most frequent and severe complications of common procedures, including:
a. Regional anesthesia: headache, infection, local bleeding, nerve injury, and drug reactions. In patients for whom a regional technique is planned, a
discussion of general anesthesia and its attendant risks is suggested, because general anesthesia “backup” may be necessary.
b. General anesthesia: sore throat, hoarseness, nausea and vomiting, dental injury, allergic drug reactions, and cardiac dysfunction (in patients with
known cardiac disease).
c. Blood transfusion: fever, infectious hepatitis, HIV infection, and hemolytic reactions.
d. Vascular cannulations: peripheral nerve, tendon, or blood vessel injury; hemothorax; pneumothorax; and infection.
Note: In cases where risk has not been objectively defined, the patient should be so informed.
4. Extenuating circumstances. Anesthesia procedures may proceed without informed consent (e.g., in dire emergency) or with limited consent (e.g., the
Jehovah's Witness patient who agrees to anesthesia with the understanding that blood transfusions will be withheld).
VI. Anesthesia consultant's note
The preoperative anesthesia note is a medicolegal document in the permanent hospital record. As such, it should contain the following:
A. A concise legible statement of the date and time of the interview, the planned procedure, and a description of any extraordinary circumstances regarding
the anesthesia (e.g., locations outside the operating room).
B. Relevant positive and negative findings from the history, physical examination, and laboratory studies.
C. A problem list that delineates all disease processes, their treatments, and current functional limitations; medications and allergies are included.
D. An overall impression of the complexity of the patient's medical condition, with assignment to one of ASA Physical Status Classes:
Class 1. A healthy patient (no physiologic, physical, or psychologic abnormalities).
Class 2. A patient with mild systemic disease without limitation of daily activities.
Class 3. A patient with severe systemic disease that limits activity but is not incapacitating.
Class 4. A patient with an incapacitating systemic disease that is a constant threat to life.
Class 5. A moribund patient not expected to survive 24 hours with or without operation.
Class 6. A declared brain-dead patient whose organs are being removed for donor purposes.
Note: If the procedure is performed as an emergency, an E is added to the previously defined ASA Physical Status.
E. The anesthesia plan in the hospital record is used to convey a general management strategy (e.g., suggestions for further preoperative evaluation,
premedications, intraoperative monitoring, and postoperative care). If the author of the plan is not scheduled to actually administer care on the day of
surgery, this person should avoid defining precise details of the anesthetic agents or techniques to be used, because these will be determined by the
anesthesia team providing care. In the healthy uncomplicated patient, completion of a preanesthesia form is adequate, but when the history needs to be
detailed (i.e., the patient with cardiovascular disease) it should be in a formal legible progress note. If important comorbid problems are present, it is
imperative to convey this information directly to the anesthesia team responsible in advance of the surgery.
VII. Guidelines for NPO status
Generally, adults should not eat solids after midnight of the day before surgery but may have clear fluids up to 2 hours before their procedure. Infants or children
may have milk, formula, breast milk, or solid food up to 6 hours before surgery and clear liquids up to 2 hours before surgery (see Chapter 28). More restrictive
instructions may be necessary for some patients, such as those with active reflux or those undergoing gastrointestinal tract operations.
VIII. Premedication
A. The goals of administering sedatives and analgesics before surgery are to allay the patient's anxiety; prevent pain during vascular cannulation, regional
anesthesia procedures, or positioning; and facilitate a smooth induction of anesthesia. It has been shown that the requirement for these drugs is reduced
after a thorough preoperative visit by an anesthesiologist.
1. In elderly, debilitated, or acutely intoxicated patients and in those with upper airway obstruction or trauma, central apnea, neurologic deterioration, or
severe pulmonary or valvular heart disease, doses of sedatives and analgesics should be reduced or withheld.
2. Patients addicted to opioids and barbiturates should be premedicated sufficiently to prevent withdrawal during or shortly after surgery.
B. Sedatives may be given to calm the anxious patient and help provide a restful night of sleep before surgery.
1. Benzodiazepines
a. Diazepam (Valium) rarely produces significant cardiovascular or respiratory depression at recommended doses. A dose of 5 to 10 mg orally (PO) 1 to
2 hours before surgery usually suffices. Diazepam should not be given intramuscularly (IM) because injection is painful and absorption unpredictable.
b. Lorazepam (Ativan) may be used (1 to 2 mg PO) but usually causes more intense amnesia and prolonged postoperative sedation.
c. Midazolam (Versed), 1 to 3 mg IV or IM, is most frequently used in the induction area as a supplemental premedicant and provides excellent amnesia
and sedation.
2. Barbiturates such as pentobarbital (Nembutal) are rarely used for preoperative sedation, although they are occasionally used by nonanesthetists for
sedation during diagnostic procedures (e.g., endoscopy, magnetic resonance imaging, and computed tomography).
3. Droperidol (Inapsine) is a butyrophenone that produces long-acting sedation at doses of 0.03 to 0.14 mg/kg IM or IV. At low doses (0.625 to 2.5 mg IV), it
is a useful antiemetic. The use of droperidol has been related to cases of QT prolongation and/or torsades de pointes even at doses at or below the
recommended range; some cases have been fatal. Droperidol is contraindicated in patients with known or suspected QT prolongation. Use of droperidol
should be reserved for patients failing other therapies, and only after it is determined that QT prolongation does not exist. Electrocardiographic monitoring
is recommended prior to treatment and for 2 to 3 hours after treatment to monitor for arrhythmias.
C. Opioids are most frequently given in the preoperative setting to relieve pain (e.g., patient with a painful hip fracture) and occasionally when the placement of
extensive invasive monitoring devices is planned. Morphine is the primary opioid used, because it has both analgesic and sedative properties. Usual adult
doses are 5 to 10 mg IM, 60 to 90 minutes before coming to the operating room.
D. Anticholinergics are seldom used preoperatively. Occasionally useful agents include the following
1. Glycopyrrolate (0.2 to 0.4 mg IV for adults and 10 to 20 µg/kg for pediatric patients) or atropine (0.4 to 0.6 mg IV for adults and 0.02 mg/kg for pediatric
patients) is given IV during ketamine induction and during oral/dental surgery as an antisialagogue.
2. Scopolamine may be given in combination with morphine IM before cardiac surgery to provide additional amnesia and sedation. The adult dose is 0.3 to
0.4 mg IM.
E. Guidelines for prophylaxis for pulmonary aspiration have been recommended by the ASA and may be beneficial for patients at high risk for aspiration
pneumonitis, including the parturient and those with a hiatal hernia and reflux symptoms, a difficult airway, ileus, obesity, or central nervous system
depression.
1. Histamine (H ) antagonists produce a dose-related decrease in gastric acid production. Cimetidine (Tagamet), 200 to 400 mg PO, IM, or IV, and
2
ranitidine (Zantac), 150 to 300 mg PO or 50 to 100 mg IV or IM, significantly reduce both the volume and acidity of gastric secretions. Multidose
regimens (i.e., the night before and morning of surgery) are the most effective, although parenteral administration may be used to achieve a rapid (<1
hour) onset. Cimetidine has been shown to prolong the elimination of many drugs, including theophylline, diazepam, propranolol, and lidocaine,
potentially increasing the toxicity of these agents. Ranitidine has not been associated with such side effects.
2. Nonparticulate antacids. Colloidal antacid suspensions effectively neutralize stomach acid but can produce serious pneumonitis if aspirated.
Nonsuspension antacids, such as citric acid solutions (Bicitra, 30 to 60 mL, 30 minutes before induction), may be less effective in increasing gastric pH,
but their aspiration is less harmful.
3. Metoclopramide (Reglan) is a dopamine antagonist that enhances gastric emptying by increasing lower esophageal sphincter tone while simultaneously
relaxing the pylorus. An oral dose of 10 mg is given 1 to 2 hours before anesthesia or intravenously in the induction area as soon as the IV is inserted.
When administered intravenously, it should be given slowly to avoid abdominal cramping. Metoclopramide also has an antiemetic effect. Metoclopramide
can precipitate a dystonic reaction, which can be treated with diphenhydramine, 25 to 50 mg IV. Metoclopramide is contraindicated in the presence of
bowel obstruction, where it may increase retrograde peristalsis.
SUGGESTED READING
ACC/AHA task force report. Special report: guidelines for perioperative cardiovascular evaluation for noncardiac surgery. Report of the American College of Cardiology/American Heart Association
Task Force on practice guidelines (Committee on Perioperative Cardiovascular Evaluation for Noncardiac Surgery). J Cardiothorac Vasc Anesth 1996;10:540–552.
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. A Report by the Task Force on Preoperative Fasting and the Use of Pharmacologic Agents to Reduce the Risk of Pulmonary Aspiration.
http://www.asahq.org/practice/npo/npoguide.html accessed May 1, 2001.
American Society of Regional Anesthesia. Recommendations for Neuraxial Anesthesia and Anticoagulation. http://www.asra.com/items_of_interest/consensus_statements/ accessed May 1, 2001.
Eagle KA. Surgical patients with heart disease: summary of the ACC/AHA guidelines. American College of Cardiology/American Heart Association. Am Fam Physician 1997;56:811–818.
Egbert LD, Battit GE, Turndorf H, et al. The value of the preoperative visit by an anesthetist. A study of doctor-patient rapport. JAMA 1963;185:553–555.
Fleisher LA. Risk of anesthesia. In: Miller RD, ed. Anesthesia, 5th ed. New York: Churchill Livingstone, 2000:795–824.
Fleisher LA, Barash PG. Preoperative cardiac evaluation for noncardiac surgery: a functional approach. Anesth Analg 1992;74:586–598.
Olsson GL, Hallen B, Hambraeus-Jonzon K. Aspiration during anaesthesia: a computer-aided study of 185,358 anaesthetics. Acta Anaesthesiol Scand 1986;30:84–92.
Roizen MF, Foss JF, Fischer SP. Preoperative evaluation. In: Miller RD, ed. Anesthesia, 5th ed. New York: Churchill Livingstone, 2000:824–884.
Velanovich V. The value of routine preoperative laboratory testing in predicting postoperative complications: a multivariate analysis. Surgery 1991;109:236–243.
White PF. Pharmacologic and clinical aspects of preoperative medication. Anesth Analg 1986;65:963–974.
Wiklund RA, McGoldrick KE. Preoperative evaluation of preparation of patients for vitreoretinal surgery. In: Scheppens CL, Hartnett ME, Hirose T, eds. Scheppens' retinal detachment and allied
diseases, 2nd ed. Boston: Butterworth Heinemann, 2000:221–234.
2 Specific Considerations with Cardiac Disease
Clinical Anesthesia Procedures of the Massachusetts General Hospital
2
Specific Considerations with Cardiac Disease
James G. Cain
Ischemic heart disease
Physiology
Preoperative predictors of cardiac morbidity
Preoperative evaluation
Preanesthetic considerations
Noncoronary cardiac disease
Bacterial endocarditis prophylaxis
Aortic stenosis
Idiopathic hypertrophic subaortic stenosis
Aortic regurgitation
Mitral stenosis
Mitral regurgitation
Mitral valve prolapse
Congenital heart disease (CHD)
General considerations
Unrepaired congenital defects
True corrections
Corrected lesions
Palliative procedures
Cardiac transplant patient
Physiology of cardiac transplantation
Anesthetic considerations
Pacemakers
Definitions
Indications
Physiology
Preoperative evaluation of patients with permanent pacemakers
Intraoperative management
Perioperative pacing options
The automatic ICD
The atrial defibrillator
Suggested Reading
I. Ischemic heart disease. Coronary artery disease (CAD) afflicts approximately 10 million Americans. CAD increases in prevalence with age: 4 in 1,000 for ages
15 to 44, 48 in 1,000 for ages 45 to 65, and 80 in 1,000 for those over age 65. Nearly 10 million noncardiac surgical patients are at risk annually for
perioperative morbidity and mortality from ischemic cardiac events. These include 1 million with diagnosed CAD (angina or Q waves on electrocardiogram
[ECG]), 2 to 3 million with two or more coronary risk factors, and 4 million older than age 65. Perioperative cardiac events, including myocardial infarction (MI),
unstable angina, congestive heart failure (CHF), and serious arrhythmias, are the leading cause of perioperative deaths.
A. Physiology
1. Oxygen supply–demand balance. Myocardial ischemia occurs when oxygen demand exceeds delivery.
a. Supply. The myocardium is perfused via coronary arteries. The left coronary artery branches into the left anterior descending and the circumflex
to supply most of the left ventricle (LV), interventricular septum (including atrioventricular [AV] bundles), and left atrium. The right coronary artery
supplies the interventricular septum, including the sinoatrial and AV nodes. Coronary arteries are end arteries with minimal collateralization.
Myocardial oxygen supply depends on coronary artery diameter, LV diastolic pressure, aortic diastolic pressure, and arterial oxygen content.
1. Coronary blood flow is dependent on the aortic root to downstream coronary pressure gradient. Most coronary blood flow occurs during diastole.
Coronary artery blood flow in normal individuals is primarily controlled through local mediators. Patients with significant coronary diseases may be
maximally dilated at rest.
2. Heart rate is inversely proportional to the length of diastole. Faster heart rates decrease the duration of maximal coronary perfusion.
3. Blood oxygen content is determined by hemoglobin concentration, oxygen saturation, and dissolved oxygen. Increasing inspired oxygen fraction
and/or hemoglobin concentration increases blood oxygen content.
b. Demand. Myocardial oxygen consumption (M o ) increases most by increasing ventricular wall tension and heart rate (velocity of shortening) and, to
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a lesser degree, contractility.
1. Ventricular wall tension is modeled by Laplace's law: wall tension equals transmural ventricular pressure multiplied by the cardiac radius divided
by twice wall thickness. Changes in these parameters affect oxygen demand.
2. Heart rate. Tachycardia is well tolerated in normal hearts. Atherosclerotic coronary arteries may not adequately dilate to meet increased demands
of faster heart rates.
3. Contractility increases with the increased chronotropy, myocardial stretch, calcium, and catecholamines. Increasing contractility increases oxygen
consumption.
c. Supply and demand balance. Atherosclerosis is the most common etiology for supply–demand imbalances. Conditions such as aortic stenosis,
systemic hypertension, and hypertrophic cardiomyopathy, which are characterized by marked ventricular hypertrophy and high intraventricular
pressures, may also increase M o and create imbalances, even in the setting of normal coronary arteries. The goal of treatment is to improve the
2
supply–demand balance.
1. Increase supply
a. Increase coronary perfusion pressure with administration of volume or a-adrenergic agonists to increase aortic diastolic pressure.
b. Increase coronary blood flow with nitrates and calcium channel antagonists to dilate coronary arteries.
c. Increase oxygen content by raising hemoglobin concentration or oxygen partial pressure.
2. Decrease demand
a. Decrease heart rate either directly with b-adrenergic antagonists or indirectly by decreasing sympathetic tone with opioids and anxiolytics.
b. Decrease ventricular size (decrease wall tension) by decreasing preload with nitrates, calcium channel antagonists, or diuretics. Occasionally,
increasing inotropy may decrease demand by decreasing ventricular size and wall tension.
c. Decreasing contractility may decrease M o if ventricular size and wall tension do not increase excessively. Calcium channel blockers and
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volatile anesthetics may decrease contractility.
d. Intraaortic balloon counter pulsation increases coronary perfusion pressure by augmenting diastolic pressure. It also reduces resistance to
LV ejection, thereby reducing LV size and wall tension.
B. Preoperative predictors of cardiac morbidity
Primary risk factors associated with CAD directly influence onset, duration, severity of heart disease, and risk of cardiac morbidity. Secondary risk factors are
associated with and influenced by primary risk factors.
1. Primary risk factors
a. CHF may be an important predictor of perioperative morbidity. A large number of patients with CHF die suddenly, often from arrhythmias. Without a
treatable precipitating etiology, life expectancy may be from 6 months to 4 years.
b. Angina is classified as stable or unstable. Stable angina is induced by exercise or stress, resolves with rest, and can be controlled with medication.
Unstable angina occurs at rest or is characterized by increasing severity or number of anginal episodes. Unstable angina may be difficult to control
medically. Myocardial ischemia may also be evidenced by fatigue, dyspnea, arrhythmia, and/or CHF. Most ischemia, however, is asymptomatic or