First exposure to general surgery first exposure series

Aldrink, MD General Surgery Resident Department of Surgery Duke University Medical Center Durham, North Carolina Chapter 15 Steffen Baumeister, MD Research Fellow Division of Plastic, R

Trang 2

FIRST EXPOSURE TO GENERAL SURGERY

Danny O Jacobs, MD, MPH

Professor and Chairman Department of Surgery Duke University School of Medicine Durham, North Carolina

McGRAW-HILL

M EDICAL P UBLISHING D IVISION

New York / Chicago / San Francisco / Lisbon / London / Madrid / Mexico City Milan / New Delhi / San Juan / Seoul / Singapore / Sydney / Toronto

Trang 3

publication may be reproduced or distributed in any form or by any means, or stored in a database or retrieval system, without the prior written permission of the publisher

0-07-149129-5

The material in this eBook also appears in the print version of this title: 0-07-144140-9.

All trademarks are trademarks of their respective owners Rather than put a trademark symbol after every occurrence of a trademarked name, we use names in an editorial fashion only, and to the benefit of the trademark owner, with no intention of infringement of the trademark Where such designations appear in this book, they have been printed with initial caps

McGraw-Hill eBooks are available at special quantity discounts to use as premiums and sales promotions,

or for use in corporate training programs For more information, please contact George Hoare, Special Sales, at george_hoare@mcgraw-hill.com or (212) 904-4069

TERMS OF USE

This is a copyrighted work and The McGraw-Hill Companies, Inc (“McGraw-Hill”) and its licensors reserve all rights in and to the work Use of this work is subject to these terms Except as permitted under the Copyright Act of 1976 and the right to store and retrieve one copy of the work, you may not decom- pile, disassemble, reverse engineer, reproduce, modify, create derivative works based upon, transmit, dis- tribute, disseminate, sell, publish or sublicense the work or any part of it without McGraw-Hill’s prior consent You may use the work for your own noncommercial and personal use; any other use of the work is strictly prohibited Your right to use the work may be terminated if you fail to comply with these terms THE WORK IS PROVIDED “AS IS.” McGRAW-HILL AND ITS LICENSORS MAKE NO GUARAN- TEES OR WARRANTIES AS TO THE ACCURACY, ADEQUACY OR COMPLETENESS OF OR RESULTS TO BE OBTAINED FROM USING THE WORK, INCLUDING ANY INFORMATION THAT CAN BE ACCESSED THROUGH THE WORK VIA HYPERLINK OR OTHERWISE, AND EXPRESS-

LY DISCLAIM ANY WARRANTY, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO IMPLIED WARRANTIES OF MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE McGraw-Hill and its licensors do not warrant or guarantee that the functions contained in the work will meet your requirements or that its operation will be uninterrupted or error free Neither McGraw-Hill nor its licensors shall be liable to you or anyone else for any inaccuracy, error or omission, regardless of cause,

in the work or for any damages resulting therefrom McGraw-Hill has no responsibility for the content of any information accessed through the work Under no circumstances shall McGraw-Hill and/or its licensors be liable for any indirect, incidental, special, punitive, consequential or similar damages that result from the use of or inability to use the work, even if any of them has been advised of the possibility

of such damages This limitation of liability shall apply to any claim or cause whatsoever whether such claim or cause arises in contract, tort or otherwise

DOI: 10.1036/0071441409

Trang 4

We hope you enjoy this McGraw-Hill eBook! If you’d like more information about this book, its author, or related books and websites,

please click here.

Professional

Want to learn more?

Trang 7

C O N T E N T S

Chapter 1 Preoperative Assessment and Preparation 3

Sandhya Lagoo-Deenadayalan, MD, PhD

Kumash R Patel, MD Steven N Vaslef, MD, PhD

Wendy R Cornett, MD

C Denise Ching, MD Aurora D Pryor, MD

L Scott Levin, MD, FACS

Chapter 6 The Postoperative Care of the Surgical Patient 91

Philip Y Wai, MD Paul C Kuo, MD, MBA Rebecca A Schroeder, MD

Chapter 7 Wound Healing and Wound Management 121

Detlev Erdmann, MD, PhD Tracey H Stokes, MD

v

Trang 8

Chapter 11 Hepatobiliary Surgery 214

David Sindram, MD, PhD Janet E Tuttle-Newhall, MD

Bradley H Collins, MD, FACS

Dev M Desai, MD, PhD

Michael R Zenn, MD, FACS

Jennifer H Aldrink, MD John A Olson, Jr., MD, PhD

Keshava Rajagopal, MD, PhD

Chapter 17 Head and Neck Surgery Reconstruction 341

Steffen Baumeister, MD

L Scott Levin, MD, FACS

Jose L Trani Jr., MD Matthew G Hartwig, MD Brian Lima, MD

Mayur B Patel, MD Jacob N Schroder, MD Tamarah J Westmoreland, MD Rebecca P Petersen, MD, MSc Anthony Lemaire, MD Jin S Yoo, MD

Trang 9

Jennifer H Aldrink, MD

General Surgery Resident

Department of Surgery

Duke University Medical Center

Durham, North Carolina

Chapter 15

Steffen Baumeister, MD

Research Fellow

Division of Plastic, Reconstructive,

Maxillofacial and Oral Surgery

Chapter 17

C Denise Ching, MD

Chapter 4

Bradley H Collins, MD, FACS

Assistant Professor of Surgery

Division of General Surgery,

Transplantation

Chapter 12

Wendy R Cornett, MD

Medical University of South Carolina

Charleston, South Carolina

Chapter 3

Dev M Desai, MD, PhD

Assistant Professor of SurgeryDivision of General SurgeryDepartment of SurgeryDuke University Medical CenterDurham, North Carolina

Chapter 13

Detlev Erdmann, MD, PhD

Assistant Professor of SurgeryDivision of Plastic, Reconstructive,Maxillofacial and Oral SurgeryDepartment of Surgery

Duke University Medical CenterDurham, North Carolina

Chapter 7

Matthew G Hartwig, MD

General Surgery ResidentDepartment of SurgeryDuke University Medical CenterDurham, North Carolina

Chapter 18

Danny O Jacobs, MD, MPH

Professor and ChairmanDepartment of SurgeryDuke University School

of MedicineDurham, North Carolina

Paul C Kuo, MD, MBA

Professor and ChiefDivision of General SurgeryDepartment of SurgeryDuke University Medical CenterDurham, North Carolina

Chapter 6

Trang 10

Sandhya Lagoo-Deenadayalan,

MD, PhD

Chapter 1

Anthony Lemaire, MD

Chapter 18

L Scott Levin MD, FACS

Professor and Chief

Division of Plastic/Reconstructive/

Oral Surgery

Professor of Orthopaedic Surgery

Chapter 5, 17

Brian Lima, MD

Chapter 18

Shu S Lin, MD, PhD

Division of Thoracic and

Cardiovascular Surgery

Chapter 8

Carlos E Marroquin, MD

Assistant Professor of SurgeryDepartment of SurgeryDuke University Medical CenterDurham, North Carolina

Chapter 9

John A Olson, Jr., MD, PhD

Associate Professor of SurgeryDivision of General SurgeryDepartment of SurgeryDuke University Medical CenterDurham, North Carolina

Chapter 15

Kumash R Patel, MD

Assistant Professor of SurgeryDepartment of Surgery Tulane University HospitalNew Orleans, LA

Chapter 2

Mayur B Patel, MD

Chapter 18

Rebecca P Petersen, MD, MSc

Chapter 18

Aurora D Pryor, MD

Assistant Professor of SurgeryDivision of General SurgeryDepartment of SurgeryDuke University Health SystemDurham, North CarolinaChapter 4

Trang 11

Keshava Rajagopal, MD, PhD

Chapter 16

Jacob N Schroder, MD

Chapter 11

Tracey H Stokes, MD

Chief Resident in Plastic Surgery

Division of Plastic, Reconstructive,

Maxillofacial and Oral Surgery

Chapter 7

Jose L Trani, Jr., MD

Chapter 18

Janet E Tuttle-Newhall, MD

Assistant Professor of SurgeryDivision of General Surgery/Transplant Surgery/Critical CareDepartment of Surgery

Duke University Medical CenterDurham, North Carolina

Chapter 11

Steven N Vaslef, MD, PhD

Associate Professor of SurgeryDirector, Trauma Services andChief, Section of Trauma andCritical Care

Division of General SurgeryDepartment of SurgeryDuke University Medical CenterDurham, North Carolina

Chapter 2

Philip Y Wai, MD

General Surgery Resident Yale School of Medicine New Haven, ConnecticutChapter 6

Tamarah J Westmoreland, MD

Chapter 18

Rebekah R White, MD

Surgical Oncology FellowMemorial Sloan-KetteringCancer Center

New York, New YorkChapter 10

Trang 12

Jin S Yoo, MD

Chapter 18

Michael R Zenn, MD, FACS

Associate ProfessorDivision of Plastic/ReconstructiveOral Surgery

Department of SurgeryDuke University Medical CenterDurham, North Carolina

Chapter 14

Trang 13

We have endeavored to prepare a concise “mini-textbook” that would bemost useful for medical students as they begin their ﬁrst clinical rotations ongeneral surgery services Our goal was to present the material as succinctly

as possible while emphasizing the fundamental principles relevant to eachtopic area We asked ourselves, what do we wish had been written in thetexts we read as medical students and used the answers to these questions

to guide our efforts

Danny O Jacobs, MD, MPH

Trang 14

We’d like to thank Michelle Fisher for her many contributions that helped tomake “First Exposure to Surgery” possible.

xii

Trang 15

FUNDAMENTAL PRINCIPLES

Trang 17

PREOPERATIVE ASSESSMENT AND

PREPARATION

Sandhya Lagoo-Deenadayalan, MD, PhD

INTRODUCTION

The aim of a preoperative evaluation of a patient is to assess the ﬁtness of the

individual for anesthesia and surgery Given a choice of any one test for operative assessment of a patient, a thorough history and physical examina-tion will be the test of choice This time—honored and inexpensive test canaccount for more than two-thirds of all diagnoses made and should direct allpreoperative testing

pre-A well-conducted history and physical examination answer severalimportant questions:

• Is this a healthy patient?

• What is the indication for surgery?

• Is the surgical procedure low risk, intermediate risk, or high risk?

• What is the functional status of the patient?

• What is the effect of the present condition on the patient?

• What improvement is expected after surgery?

Answers to these questions should then direct preoperative testing andmanagement.1Preoperative tests rarely detect unsuspected medical condi-tions The tests selected should therefore evaluate existing illness, screen forconditions that could affect outcomes in the perioperative period, and help

to determine perioperative risks Existing illnesses that need evaluation andpossible treatment prior to surgery include hypertension, diabetes mellitus,cardiac, vascular, pulmonary, renal, and hepatic diseases The pregnant

Trang 18

patient, the geriatric patient, the patient with oncologic disease, tion, or coagulation disorders also needs directed evaluations.

malnutri-THE HEALTHY PATIENT

The initial preoperative evaluation of a patient should be supplemented by acomplete assessment of the patient’s general health This involves a thoroughhistory and physical examination Complete blood counts should be obtained

in all adult women, men over 60 years of age, and patients with hematologicdisorders Blood urea and electrolytes should be tested in all patients over

60 years of age, and in patients with known cardiovascular and renal disease,diabetes, and in patients on steroids, diuretics, and angiotensin-convertingenzyme (ACE) inhibitors An electrocardiogram (ECG) is indicated in menover 40 years, women over 50 years, and in patients with cardiovasculardiseases and diabetes Posteroanterior and lateral chest x-rays are indicated

in patients with cardiovascular and respiratory diseases, in patients withmalignancy, and those undergoing major thoracic or abdominal surgery.2

A history of the current diagnosis and the planned procedure should beobtained The history should include information regarding any knownmedical problems and ongoing treatment, previous surgical procedures, andproblems if any during previous anesthesia These can include difﬁcult intu-bation, bleeding tendencies, and anesthetic jaundice Family history of prob-lems during anesthesia or surgery should be obtained These can make theanesthesiologist aware of potential problems such as malignant hyperther-mia, bleeding tendencies, or thrombophilia In addition to routine informa-tion about family history, a strong family history of allergies should alert thesurgeon to the possibility of hypersensitivity to drugs

An exhaustive history of drug allergies, sensitivities, and current orrecently taken medications should be obtained Medications such as digi-talis, insulin, and corticosteroids should be maintained and their doses care-fully regulated in the perioperative period If the patient is on corticosteroids

or if it has been discontinued within a month of surgery, he or she may have

a hypofunctioning adrenal cortex resulting in impaired physiologic response

to surgical stress This may necessitate administration of steroids in the operative period Long-term use of barbiturates, opiates, and alcohol may beassociated with increased tolerance to anesthetic drugs History of smokingand alcohol use should be obtained A review of constitutional symptoms—fever, weight loss, heartburn, and regurgitation—is critical

peri-PHYSICAL EXAMINATION

A thorough physical examination should be conducted Assessment of eral appearance, vital signs, body mass index, jugular venous pressure andpulsation, evaluation of the head and neck to gauge airway problems and

Trang 19

gen-lack of supple neck movements, auscultation of the lung, precordial tion and auscultation, abdominal inspection for scars from previous surgeryand abdominal palpation, examination of peripheral arterial pulses (carotid,radial, femoral, popliteal, posterior tibial, and dorsalis pedis) and of theextremities for edema are critical Cyanosis, pallor, jaundice, dyspnea, nutri-tional status, skeletal deformity, and anxiety should be recognized Anassessment of mental status and a brief neurologic examination should beconducted A rectal and pelvic examination should be performed unless con-traindicated Surgery-speciﬁc risk can be determined based on several crite-ria (Table 1-1).

palpa-Brieﬂy, high-risk cases in which the incidence of morbidity and mortalitymay be greater than 5 percent include aortic and major vascular procedures,intra-abdominal resections, surgery with major ﬂuid shifts, and gyneco-logic and oncology procedures Intermediate-risk cases have a morbidity

of 1–5 percent and include head and neck resections, carotid tomy, major orthopedic procedures, laparoscopic intra-abdominal proce-dures, and hysterectomy or radical prostatectomy Low-risk cases includemost endoscopic procedures, breast surgery, ophthalmologic procedures,and hernia repair

endarterec-Table 1-1 Surgery-speciﬁc Risk

High Risk >5%

Emergencies

Aortic and major vascular procedures

Major intra-abdominal resections

Surgery with major ﬂuid shifts

Gynecologic and oncology procedures

Intermediate Risk 1–5%

Head and neck resections

Carotid endarterectomy

Major orthopedic procedures

Laparoscopic intra-abdominal procedure

Hysterectomy or radical prostatectomy

Trang 20

Identiﬁcation of functional status is a critical part of a preoperative uation and is accomplished during a physical examination The AmericanSociety of Anesthesiology (ASA) Physical Status Classiﬁcation is a com-monly used grading system that accurately correlates functional status with

eval-morbidity and mortality following surgery (Table 1-2) ASA Class 1 indicates

a healthy patient with no gross organic disease ASA Class 2 indicates a

patient with mild or moderate systemic disease without functional

impair-ment, while ASA Class 3 indicates a patient with organic disease with nite functional impairment A Class 4 patient is one with a severe disease that

defi-is life threatening and a Class 5 patient defi-is one who defi-is moribund and has a

low likelihood of survival Mortality is expected to be 0.05 percent in ASAClass 1 patients, 0.4 percent in ASA Class 2 patients, 4.5 percent in ASAClass 3 patients, 25 percent in Class 4 patients, and 50 percent in ASA Class 5patients

HYPERTENSION

Hypertension is a minor clinical predictor of increased preoperative

cardio-vascular risk Hypertension is classiﬁed as primary (essential or idiopathic)

in 95 percent of cases Secondary hypertension is found in 5 percent of

patients The ﬁve most common causes of secondary hypertension includerenal artery stenosis, primary hyperaldosteronism, Cushing syndrome,pheochromocytoma, and aortic stenosis Several studies have suggested thatintraoperative blood pressure changes may be greater in untreated hyper-tensive patients Patients are therefore advised to take their antihypertensivemedications on the day of surgery, with the exception of diuretics These arewithheld to avoid hypovolemia or hypokalemia

Application of ASA grading to hypertensive disease classiﬁes thosepatients with well-controlled hypertension on a single agent as ASA Class 2

Table 1-2 ASA Classiﬁcation

1 No gross organic disease, healthy patient

2 Mild or moderate systemic disease without functional

impairment

3 Organic disease with deﬁnite functional impairment

4 Severe disease that is life threatening

5 Moribund patient, not expected to survive

Trang 21

patients and those patients with poorly controlled hypertension and on tiple drugs as ASA Class 3 patients Elegant studies by Goldman3revealedthat elective surgery in patients with inadequately controlled hypertensionwas not associated with increased risk of perioperative cardiac morbidityprovided the diastolic blood pressure was less than 110 mmHg and periop-erative blood pressure was closely monitored Discontinuation of antihyper-tensive therapy can be dangerous Examples include rebound hypertensionafter discontinuation of a centrally acting α2-adrenergic agonist such asclonidine or congestive heart failure (CHF) in the perioperative period afterwithholding ACE inhibitors β-Adrenergic blockade should be continuedthroughout the preoperative period Myocardial ischemia is associated withtachycardia but not with acute changes in blood pressure Beta-blockers such

mul-as atenolol are found to be cardio protective A study by Mangano andGoldman4has shown that beta-blockers given pre- and postoperatively canreduce the risk of death in patients with known coronary artery disease(CAD) or at risk for CAD Contraindications to the use of beta-blockersinclude a heart rate of less than 55, systolic blood pressure of less than 100,bronchospasm, CHF, and patients with second- or third-degree heartblock A recent myocardial infarction (MI) is the single most important fac-tor that can predict perioperative infarction The risk is greatest within theﬁrst 3 months after an infarction In a patient with a recent MI, electivesurgery should be postponed to after 6 months, when the risk of reinfarctiondrops to 4.5 percent as opposed to 30 percent within 3 months Urgentsurgery should be preceded by coronary artery bypass or stenting

In cases of emergency surgery, uncontrolled hypertension should not be

a deterrent to proceeding with surgery Short-acting beta-blockers can beused to control hypertension in the perioperative period Ketamine should

be avoided, as tachycardia, hypertension, and increased intracranial sure are all associated with its use Most importantly, perioperative treat-ment of hypertension with the parenterally administered drugs mentionedearlier should be undertaken only after optimization of ventilation, oxy-genation, and circulation in the patient

pres-CARDIAC DISEASE

A careful history and physical examination can shed light on risk factors forcoronary disease such as smoking, hypertension, diabetes, hypercholes-terolemia, and a family history of CAD, valvular disease, CHF, arrhythmias,cerebrovascular disease, and peripheral vascular disease Clinical predictors,cardiac risk for the procedure (Table 1-3), and functional status of the patientshould determine the need for preoperative cardiac workup.5

Perioperative cardiac and long-term risks are increased in patients

unable to meet a 4-MET demand MET is a metabolic equivalent Greater than

Trang 22

10 METs indicate an individual with excellent functional status, a patientinvolved in competitive sports, aerobics, jogging, and so on Between 4 and

10 METs indicates a patient who can climb one ﬂight of steps, walk up a hill,

or walk a mile in 15 min Less than 4 METs indicates a patient unable to meetthe above criteria Stable angina with occasional use of nitroglycerin classi-ﬁes a patient as an ASA Class 2 patient, whereas unstable angina or regularuse of nitroglycerin classiﬁes a patient as ASA Class 3 Major clinical risk fac-tors should be stabilized before surgery This may require intervention such

as coronary angiography, angioplasty or stenting, or cardiac surgery.Patients with intermediate clinical risk and poor functional capacity shouldundergo noninvasive testing Those with good functional capacity needinvasive testing only for high-risk procedures Patients with minor or noclinical risk and poor functional capacity need invasive testing only in case

of high-risk procedures Those with good functional capacity can undergosurgery without further testing

New invasive studies are designed to determine the presence and ity of reversible ischemia induced by stress The stress can be induced byexercise or with drugs such as dobutamine or dipyridamole in patients whocannot exercise Test tools include ECG, echocardiography, and radionuclidestudies using thallium and/or sestamibi Patients with low- or intermediate-risknoninvasive testing can proceed with surgery, while those with high-risk

sever-Table 1-3 Clinical Predictors of Increased Perioperative Cardiovascular Risk Major Risk

Unstable coronary syndromes—recent MI, unstable angina

Trang 23

noninvasive testing should undergo coronary angiography and a larization procedure prior to noncardiac surgery In high-risk cardiacpatients, perioperative hemodynamic monitoring is essential This mayinvolve arterial lines and central venous lines or pulmonary artery cathetersthat can help assess hemodynamic status Such monitoring can help opti-mize perioperative volume resuscitation or restriction, diuretics, afterloadreduction, and the use of inotropic drugs.

Early and late postoperative pulmonary complications were leadingcauses of morbidity and mortality in surgery A detailed history should beobtained to evaluate the history of asthma, bronchospasm, duration of priorasthma therapy, previous hospitalization, steroid use, and prior need formechanical ventilation Elective surgery should be postponed in cases ofacute upper respiratory tract infections Additional information regardingsmoking history (pack-years), nutritional status, concomitant heart disease,and current therapy including home oxygen use should be sought Physicalﬁndings that suggest right ventricular failure include peripheral edema, aprominent right ventricular impulse, or neck vein distention

A preoperative chest radiograph helps to evaluate lung disease andserves as a basis for comparison in the perioperative period Signiﬁcant air-ﬂow obstructions can be associated with a normal x-ray Findings such asdepression of the right hemidiaphragm at or below the seventh rib in ananteroposterior view, a cardiac silhouette with a transverse diameter of lessthan 11.5 cm, and a retrosternal air space of greater than 4.4 cm on a lateralview should raise concern for chronic lung disease Laboratory studies such

as elevated serum bicarbonate suggest respiratory acidosis and cythemia may suggest chronic anemia

Trang 24

poly-Patients at high risk for pulmonary complications include those withdocumented pulmonary disease (chronic obstructive pulmonary disease[COPD] or chronic bronchitis), those with history of heavy smoking andcough, poor perioperative nutrition, and those undergoing thoracicsurgery or upper abdominal surgery Arterial blood gases on room air andpulmonary function testing should be performed in these patients Anarterial oxygen tension (PaO2) of less than 60 mmHg correlates with pul-monary hypertension and a partial arterial pressure (PaCO2) of greaterthan 45 mmHg is associated with increased perioperative morbidity.Pulmonary function criteria that indicate increased risk include a forcedvital capacity (FVC) less than 50 percent of predicted, forced expiratoryvolume (FEV1) less than 50 percent of predicted or less than 2.0 L, or anFEV1/FVC ratio of less than 0.65 If spirometric parameters improve withbronchodilator therapy, the therapy should be continued during the peri-operative period This improves airﬂow obstruction, lung mechanism, andgas exchange Patients undergoing pulmonary resection should have splitfunction studies with either bronchospirometry or radionuclide imaging.

An FEV1of 800 mL in the contralateral lung is required to proceed with apneumonectomy

Cessation of cigarette smoking is helpful in patients smoking morethan 10 cigarettes per day Smoking doubles the risk of pulmonary compli-cations and the risk persists for 3–4 months after the cessation of smoking.However, patients should be informed that even 48 h of cessation coulddecrease carboxyhemoglobin levels to that of a nonsmoker, abolish theeffect of nicotine on the cardiovascular system, and improve mucosalciliary function Patients should be educated about the merits of deepbreathing, coughing, incentive spirometry, and early ambulation in thepostoperative periods Various preoperative risk reduction strategies sug-gested by Smetana6include advice regarding cessation of cigarette smok-ing, treatment of airﬂow obstruction in patients with COPD or asthma,administering antibiotics and delaying surgery when respiratory infection

is present, and educating patients regarding lung-expansion maneuvers(Table 1-4)

Table 1-4 Preoperative Pulmonary Risk Reduction Strategies

• Encourage cessation of cigarette smoking for at least 8 weeks

• Treat airﬂow obstruction in patients with COPD or asthma

• Administer antibiotics and delay surgery if respiratory infection is present

• Begin patient education regarding lung-expansion maneuvers

Trang 25

RENAL DISEASE

Preexisting renal insufﬁciency (RI) is an independent risk factor for vascular death after elective surgery due to the presence of multiple risk fac-tors such as hypertension, hyperlipidemia, and abnormal carbohydratemetabolism Renal function is classiﬁed into three categories based on serumcreatinine: normal function with creatinine less than 1.5 mg/dL, mild RIwith serum creatinine of 1.5–3 mg/dL, and severe chronic RI with serumcreatinine greater than 3.0 mg/dL

cardio-Patients with mild RI have a high incidence of coexisting cardiovasculardisease In patients with mildly elevated creatinine that has not been previ-ously evaluated, urinalysis, 24-h urine for creatinine clearance, and consul-tation with an internist are indicated before an elective operation Serum cre-atinine is a good estimate of renal function; however, it may be inaccurate inpatients with ascites, pregnancy, obesity, and edema Glomerular ﬁltration,which can be calculated from the 24-h creatinine clearance, is the gold stan-dard for renal function In patients with severe chronic RI, elective surgeryshould be coordinated with their nephrologist for optimal timing of dialysis;preferably within 24 h of surgery Perioperative ﬂuid management is critical

in these patients and even more so in patients who are not dialysis dent Laboratory values to be monitored include hematocrit, prothrombintime (PT), activated partial thromboplastin time (aPTT), and platelets andelectrolytes before and after surgery (serum potassium, calcium phosphate,and magnesium) Stable normochromic-normocytic anemia (hematocrit of25–30) is well tolerated in these patients Nephrotoxic agents such as contrastdyes and aminoglycosides should be avoided Enﬂurane should be avoideddue to the potential for ﬂuorane nephrotoxicity

depen-The acutely ischemic kidney is more vulnerable to subsequent ischemicinsults than the normal kidney Any acute deterioration in renal functionpreoperatively should therefore be investigated before proceeding withanesthesia and surgery

HEPATIC DISEASE

Mortality from anesthesia and surgery can be high in patients with liver ease even with simple procedures This is especially true in the case ofunrecognized liver disease or in the case of acute deterioration of liver func-tion Common causes of jaundice include nonhepatic, obstructive, and acuteparenchymal jaundice and jaundice associated with chronic liver disease.Evaluation of a patient with hepatic disease should include a history ofjaundice, hepatotoxic drugs, history of alcoholism, and symptoms of liverdisease Signs of chronic liver disease and scleral icterus should be recog-nized Liver function tests, albumin, and PT should be measured The most

Trang 26

useful classiﬁcation regarding the risk of surgery in patients with liver

dis-ease is Child’s Classiﬁcation Factors taken into account include bilirubin,

albumin, nutrition, encephalopathy, and ascites (Table 1-5)

Modiﬁable risk factors that should be addressed in these patients prior tosurgery include correction of ascites, preservation of renal function, control

of glucose and electrolyte abnormalities, improved nutrition, and treatment

of encephalopathy Cirrhotic patients present a signiﬁcant challenge in theperioperative period Factors that demand speciﬁc attention includeintravascular volume, optimization of medical management of ascites,avoidance of hyponatremia, prevention of gastrointestinal bleeding, andproviding nutrition supplemented with thiamine Stress ulcer prophylaxisshould be implemented with parenteral H2-blocker or antacids Risk ofencephalopathy in patients with advanced disease can be decreased by gutdecontamination and/or lactulose administration

VASCULAR DISEASE

Many of the risk factors contributing to peripheral vascular disease (e.g., betes mellitus, tobacco use, and hyperlipidemia) are also risk factors forCAD Peripheral vascular disease is invariably an indicator of cardiac dis-ease Morbidity and mortality in the perioperative period are generallyrelated to cardiac causes The usual symptomatic presentation for CAD inthese patients may be obscured by exercise limitations imposed by advancedage or intermittent claudication, or both Major arterial operations often aretime consuming and may be associated with substantial fluctuations inintravascular fluid volumes, cardiac filling pressure, systemic blood pres-sure, heart rate, and thrombogenicity Marked improvement in management

dia-of hemodynamics and myocardial oxygen supply and demand in the ating room have resulted in improved outcomes due to the reduced inci-dence of major hypoxic episodes Preoperative cardiac evaluation in patientswith vascular disease is crucial in order to optimize perioperative care It is

oper-Table 1-5 Child’s Classiﬁcation

controlled

Trang 27

generally felt that preoperative coronary artery revascularization should bereserved only for patients with unstable cardiac symptoms A study con-ducted by McFalls et al.7illustrates this point Patients scheduled to undergovascular surgery and found to be at increased risk for perioperative cardiaccomplications and clinically signiﬁcant CAD were randomized to two treat-ment arms These were revascularization or no vascularization before elec-tive vascular surgery They concluded that coronary revascularization beforeelective surgery does not signiﬁcantly affect long-term outcome Therefore,patients with stable cardiac symptoms cannot be recommended to undergocoronary revascularization If a carotid bruit is found during a routine pre-operative physical evaluation in a patient undergoing nonvascular surgery,further studies may be needed to determine the need and timing for carotidsurgery In patients undergoing cardiopulmonary bypass, carotid atheroscle-rosis is a risk factor for hemispheric stroke.8

ANEMIA AND COAGULATION DISORDERS

Patients with hemoglobin of less than 9 g/dL can have signiﬁcant surgicalmorbidity A peripheral blood smear may indicate the etiology of the anemia.Macrocytosis or microcytosis suggests signiﬁcant anemia, target cells areseen in splenic hypofunction, and spherocytes and schistocytes are seen inhemolytic anemias The usual initial screening coagulation tests include a

PT, aPTT, and a platelet count

Platelet Disorders

Qualitative and quantitative defects are seen in platelets in the presence ofuremia and liver disease Platelet aggregation studies and a bleeding timetest can identify qualitative defects in platelets In idiopathic thrombocy-topenic purpura, intravenous immune globulin 2 g/kg over 2–4 days can begiven to increase platelet counts If the thrombocytopenia is drug induced,the drug should be stopped and the patient allowed to recover prior to oper-ation If the surgery cannot be delayed, platelet transfusion should beundertaken

Sickle Cell Anemia

In patients with sickle cell anemia or trait, deoxygenated hemoglobin goes polymerization and forms characteristic sickle cells These can blocksmall vessels resulting in vasoocclusion Diagnosis is conﬁrmed by the sicklesolubility test and high-performance liquid chromatography Patients willneed to be transfused with hemoglobin of 9–10 g/dL prior to surgery.Dehydration, hypoxia, and pain should be avoided with intravenoushydration, oxygen, and adequate pain control to decrease the risk of a sicklecell crisis

Trang 28

under-Von Willebrand Disease

Desmopressin 0.3 µg/kg IV is administered every 12–24 h for 5–7 days TheFactor VIII: vWF ratio should be 60 percent for minor surgery and 80 percentfor major surgery If no effect is seen, cryoprecipitate can be administered(cryoprecipitate contains 80–100 units of vWF/10 U)

The main concern for the anesthetist in the perioperative management ofdiabetic patients is the avoidance of harmful hypoglycemia; mild hyper-glycemia is more acceptable This has been attributed to the difﬁculties of mea-suring blood glucose when the reduced level of consciousness preoperativelymasks signs and symptoms of hypoglycemia The immediate perioperative

Trang 29

problems facing the diabetic patient are (1) surgical induction of the stressresponse with catabolic hormone secretion; (2) interruption of food intake,which may be prolonged following gastrointestinal procedure; (3) alteredconsciousness, which masks the symptoms of hypoglycemia and necessi-tates frequent blood glucose estimations; and (4) circulatory disturbancesassociated with anesthesia and surgery, which may alter the absorption ofsubcutaneous insulin.

In patients who are dehydrated, vomiting, have severe abdominal pain,and are on the verge of obtundation, there should be a high index of suspi-cion for diabetic ketoacidosis (DKA) Diagnostic criteria for DKA includeblood glucose greater than 700 mg/dL, serum osmolarity greater than

340 mOsmol/L, and acidosis Treatment includes obtaining an ECG to ruleout a silent infarct, ﬂuid replacement with hypotonic saline, administering

5 percent dextrose after the blood glucose falls below 250 mg/dL, and toring and supplementing potassium

moni-Carcinoid Tumors

Adequate hydration is extremely important in patients who present with cinoid syndrome resulting from vasoactive substances released by the tumor.Increased levels of serotonin cause diarrhea, abdominal cramping, respiratorydistress due to bronchospasm, and hypertension In patients with long-standing carcinoid, an echocardiogram should be obtained to test for rightheart failure Antihistaminics can be used to counteract the effect of histaminesand octreotide can be used to block the release of hormonal substances

car-Pheochromocytoma

A patient with pheochromocytoma needs preoperative pharmacologicmanipulation with alpha-blockade ﬁrst, followed by possible beta-blockade.This is best accomplished by coordinated treatment of the patient by the sur-geon, the anesthesiologist, and the referring physician Alpha-blockade issuggested for 7–10 days preoperatively using phenoxybenzamine 10–40 mgorally twice daily (titrated to onset of nasal congestion and orthostatichypotension) Beta-blockade is used only after adequate alpha-blockade.Beta-blockade is attained over the last three preoperative days with propra-nolol 10 mg orally twice daily Beta-blockade is indicated in patients withtachycardia or tachyarrhythmia, and is not necessary in all patients.11

THE GERIATRIC PATIENT

The risks of a major procedure in patients over 60 years of age are increased onlyslightly in the absence of cardiovascular, renal, and other systemic diseases.Changes associated with generalized arteriosclerosis are to be expected, asare limitations of cardiac and renal reserve The incidence of silent MI

Trang 30

increases with age A thorough comprehensive preoperative evaluation istherefore very critical Occult cancer is also frequently seen in this age group,and therefore minor gastrointestinal and other complaints should be inves-tigated Older patients show less heart rate response to hypotension, andtherefore are at increased risk for orthostatic hypotension In addition, theventilatory responses to hypoxia and hypercapnia are both reduced.

In an elderly patient, it is particularly important to establish the tion for surgery, the likelihood of progression of the disease, the quality of lifewith and without surgery, and the risk of a negative outcome Negative out-comes are inﬂuenced by the nature of the disease process and the type ofintervention planned In addition to morbidity and mortality, attentionshould be paid to the quality of life and the return to preoperative functionalstatus The presence of a comorbid disease increases with age Major periop-erative complications increase with the number of comorbid conditions in allage groups but the effects are most pronounced in the youngest12and in theoldest groups (over 75 years of age) In a study of patients with colon cancer,

indica-by age 75, 50 percent of male and female patients had at least ﬁve other orders in addition to the cancer.13While only a minimal increase in mortalityand morbidity is seen in older patients who lack coexisting disease, there is athreefold increase associated with as few as two additional comorbidities

dis-A thorough history and evaluation should direct further workup and ratory testing In addition to the routine workup, special attention should bepaid to nutritional assessment and mental status evaluation Deﬁcits in nutri-tional and mental status have been found to be largely unrecognized prior toadmission in the hospital.14Baseline cognitive function in the elderly can beevaluated using the Holstein Mini Mental Status test This tests the ability fororientation, registration, attention, and the use of language

labo-The prevalence and predictive value of abnormal preoperative tory tests in elderly patients (abnormal preoperative electrolyte values andthrombocytopenia) is small and has low predictive values Although moreprevalent, abnormal hemoglobin, creatinine, and glucose values were alsonot predictive of postoperative adverse outcomes Routine preoperative test-ing for hemoglobin, creatinine, glucose, and electrolytes on the basis of ageonly may not be indicated in geriatric patients Rather, selective laboratorytesting is indicated as suggested by history and physical examination, whichwill determine patient’s comorbidities and surgical risk.15

labora-THE PREGNANT PATIENT

Surgery in a pregnant patient involves the care of two patients: the motherand the fetus One to two percent of pregnant women require surgery forindications not related to the pregnancy A thorough understanding ofchanges in the cardiovascular and respiratory physiology during pregnancy

Trang 31

is critical Anesthesia does not increase the risk of fetal anomalies; however,

it could lead to preterm labor Therefore, elective surgery should be avoidedduring the ﬁrst trimester Attention should be paid in the preoperativeperiod to the maintenance of uterine blood ﬂow and fetal oxygenation,avoidance of teratogenic drugs, and the prevention of preterm labor Whenpossible, fetal monitoring should be performed preoperatively and contin-ued in the perioperative period α-Adrenergic agonists cause uterine vaso-constriction and should be avoided Hypotension in pregnant patients can

be treated with ephedrine, a mixed α and β agonist that protects uterineblood ﬂow

The pregnant patient is at increased risk for aspiration of gastric contents.She should not have any oral intake for 6 h before surgery Magnesium sul-fate should be readily available for the treatment of preterm labor.Hydralazine is the drug of choice for hypertensive crisis in preeclampticpatients Labetalol is an alternative drug that can be used When possible,regional anesthesia should be administered instead of general anesthesia(spinal or epidural)

PATIENTS WITH A HISTORY OF VENOUS

THROMBOEMBOLISM

Elective surgery should be avoided in the ﬁrst month after an acute episode

of venous thromboembolism If this is not possible, intravenous heparinshould be given before and after the procedure while the international nor-malized ratio (INR) is below 2.0 If the aPTT is in the therapeutic range, stop-ping continuous intravenous heparin therapy 6 h before operation is usuallysufﬁcient for heparin to be cleared

Heparin therapy should not be restarted until 12 h after major surgical cedure and should be delayed even longer if there is any evidence of bleedingfrom the surgical site Heparin should be restarted without a bolus, at no morethan the expected maintenance infusion rate The aPTT should be checked

pro-12 h after restarting therapy to allow time for a stable anticoagulant response

If the patient has been receiving anticoagulant therapy for less than 2 weeksafter a pulmonary embolism or a proximal deep vein thrombosis or if therisk of bleeding during intravenous heparin therapy is considered unaccept-able, a vena caval ﬁlter should be inserted

THE ONCOLOGY PATIENT

Airway management in patients with head and neck tumors can be lenging because of the potential for airway distortions Since maintenance of

chal-an airway is a major concern in the perioperative period, the chal-anatomic effects

Trang 32

of a larger tumor must be assessed preoperatively to minimize adverseeffects Large tumors with extrinsic compression of the trachea often requireawake intubation using fiber-optic guidance Preoperative review of the CTscan of the neck is important because some large tumors may be relativelyasymptomatic prior to attempts at intubation, but may make intubationextremely difficult Another important management tool is the use of tra-cheotomy in patients with large tumors Patients in whom a difficult fiber-optic intubation is anticipated should undergo tracheotomy prior to theplanned procedure.11

A careful history is important to identify episodes of dyspnea, stridor,wheezing, or orthopnea A history of these problems and/or ﬁndings, from

a physical examination consistent with possible mediastinal compressionshould warn the surgeon to avoid general anesthesia, and obtain necessarybiopsy specimens using local anesthesia Preoperative workup of the asymp-tomatic patient with an anterior or middle mediastinal mass should include

CT scan of the chest, inspiratory and expiratory ﬂow volume loops with monary function tests, and echocardiography to rule out tracheobronchial,pulmonary artery, or cardiac compression

pul-NUTRITIONAL STATUS

Patients should undergo a preoperative nutritional assessment in advance ofsurgery Signs and symptoms of malnutrition should be actively sought.Malnutrition leads to a signiﬁcant increase in the operative death rate.Weight loss of more than 20 percent caused by illnesses such as cancer orgastrointestinal disease results in a higher death rate and a threefold increase

in postoperative infection rate The dietary history should be obtained aswell as information that can indicate basic nutritional deﬁciencies associatedwith disease states, especially vitamin deﬁciencies

In addition to a thorough history and physical examination, nutritionalassessment may include measuring serum transferrin, albumin and prealbu-min, and total urinary nitrogen (TUN) Values that suggest severe impairment

in the visceral protein mass include serum albumin of less than 2.5 g/dL,serum transferrin of less than 150 mg/dL, serum prealbumin of less than

10 mg/dL, and TUN of greater than 12 g/24 h

Well-nourished patients undergoing surgical procedures may beneﬁtfrom early postoperative feeding within 48 h If the patient is able to meetgreater than two-thirds of nutritional needs by mouth, nutritional supportcan be provided by the oral route Every effort should be made to replete theseverely malnourished patient preoperatively Supportive measures should

be instituted in cases of weight loss greater than 10 percent of body weight,and of an anticipated prolonged postoperative recovery period during

Trang 33

which the patient cannot be fed (>5–10 days for patients with preexistingsevere malnutrition) These include perioperative hyperalimentation eitherthrough the enteral or parenteral routes Enteral feeding can be providedeither through nasogastric or nasoduodenal tubes or gastrostomy tubes Thepurported advantages of enteral feeding are better substrate utilization,maintenance of gut mucosal integrity, and immunocompetence Patients inwhom the gastrointestinal tract is nonfunctional, parenteral nutrition is providedvia a central rein Central parenteral formulas are highly concentrated andtailored to meet the need for proteins, carbohydrates, fat, electrolytes, multi-vitamins, and minerals.

PREOPERATIVE MANAGEMENT OF SPECIFIC PROBLEMS

Prophylaxis for Deep Venous Thrombosis

and Pulmonary Embolism

The morbidity and mortality of deep vein thrombosis and pulmonary embolismmake it mandatory to provide prophylaxis against these catastrophes.Patients at high risk include older individuals, those with previous abdomi-nal surgery, varicose veins, increased antithrombin III levels, history ofcigarette smoking, and high platelet counts The risk is increased in patientsolder than 40 years who undergo general anesthesia for more than 30 min.The routine use of sequential compression devices on both lower extremitiesbegan in the operating room even prior to induction of anesthesia is advised.This can be continued until the patient is ambulating These devices stimulateendothelial cell ﬁbrinolytic activity and as such can be used on one leg alone or

on the upper extremity if lower extremity application is contraindicated.Low-dose heparin, 5000 units administered 2 h prior to induction andcontinued twice a day on a daily basis is effective prophylaxis However, it

is not advisable for patients with major fractures, recent head injury, orgastrointestinal bleeding In such patients, prophylactic percutaneous place-ment of an inferior vena cava ﬁlter is appropriate

Therapeutic Anticoagulation

There are several recommendations for the perioperative management ofanticoagulation in patients who cannot tolerate oral anticoagulants If apatient’s INR is between 2.0 and 3.0, four scheduled doses of warfarinshould be withheld to allow the INR to fall spontaneously to 1.5 or lessbefore surgery Warfarin should be withheld for a longer period if the INR isnormally maintained above 3.0 or if it is necessary to keep it at a lower value(i.e., less than 1.3) The INR should be measured a day before surgery toensure adequate progress in the reversal of anticoagulation; the physician thenhas the option of administering a small dose (1 mg subcutaneously) of vitamin

K, if required (i.e., if the INR is 1.8 or higher) Alternative preoperative or

Trang 34

postoperative prophylaxis, or both, against thromboembolism should beconsidered16for the period during which the INR is less than 2.0.

Antimicrobial Prophylaxis

Prophylactic antibodies are indicated for clean contaminated or nated cases Even for clean cases, prophylactic antibodies may decrease therate of infection This includes cases where prosthetic mesh is to be used Aprophylactic antibiotic covering typical skin organisms is adequate in thesecases In cases where an infection is already established, the choice of theantibiotic should be based on culture and sensitivity results and continuedfor the appropriate length of time Antibiotics should be administered in atimely fashion so that therapeutic blood levels of the antibiotic are present atthe start of the procedure

contami-In patients with open wounds or ongoing infections, culture and antibioticsensitivities should be obtained Surface cultures do not yield adequate infor-mation Instead quantitative cultures of punch biopsies from the wounds aremore precise indicators Greater than 105organisms per gram of tissue corre-spond to greater than 50 percent graft failure, whereas below 105organismsper gram of tissue correspond to greater than 80 percent graft take

Duration of the procedure correlates with higher rate of wound infection,and therefore in procedures lasting more than 4 h a second dose of the antibi-otic should be administered intraoperatively Recent work suggests that betterglycemic control with insulin infusions may reduce the incidence of deepsternal wound infections in diabetic patients who have undergone cardiacsurgery This observation is supported by a study demonstrating better preser-vations of neutrophil function with aggressive glycemic control using aninsulin infusion compared with intermittent therapy, in diabetic cardiacpatients

Preoperative Orders Regarding Diet

Patients should avoid solid foods for 12 h and liquids for 8 h prior to surgery.They are generally advised to remain nil by mouth after midnight on thenight before operation Patients undergoing esophageal surgery for achala-sia are requested to begin clear liquids 2 days prior to surgery and continuethis until midnight, the night before surgery Similarly, patients undergoingsurgery on the small intestine, colon, and rectum are advised to start clearliquids 2–3 days prior to surgery

Bowel Preparation

In addition to limiting intake of clear liquids, starting 3 days prior to surgery,patients undergoing small intestine, colon, and rectal surgery are advised toundergo a bowel preparation Various preparations can be used Thepolyethylene glycol electrolyte preparation consists of 4 L of solution thatshould be consumed over a 2–3 h period the day before surgery, before

Trang 35

administration of the oral antibiotics Alternatively, two doses of a 11/2ﬂ ozbottle of Fleet’s Phospho-Soda (hypertonic sodium phosphate solution)diluted with half a glass of water can be consumed the day before surgery;one in the early afternoon and the other in the early evening A bottle of mag-nesium citrate taken 3 days prior to surgery and then again the morningbefore surgery can also provide an adequate bowel preparation As part ofthe bowel preparation, patients are advised to take neomycin and ery-thromycin base, 1 g each orally at 1, 2, and 11 p.m the day before surgery.Metronidazole can be substituted for erythromycin.

Preoperative Orders Regarding Medications

Long-acting sulfonylureas should be stopped 48 h prior to surgery; acting agents should be omitted on the morning of surgery These medica-tions should be restarted when the patient resumes adequate oral intake.Patients are advised to take their antihypertensive medications on the day ofsurgery, with the exception of diuretics These are withheld to avoid hypov-olemia or hypokalemia The route of administration of certain drugs mayneed to be changed to parenteral in the preoperative period This may benecessary for drugs such as digitalis, other cardiac drugs, and immunosup-pressive drugs in transplant patients

short-Information Regarding Postoperative Hospital Stay, Diet, Exercise, and Return to Work

Patients should be advised about what to expect in the perioperative period.Information regarding duration of the procedure, ambulatory or in-patientstatus following surgery, and duration of hospital stay should be given.Advice regarding diet, exercise, and possible return to work allays some ofthe traditional fears about surgery Intraoperative risks of bleeding, infection,injury to adjacent structures, and need for conversion to open procedures forlaparoscopic cases should be discussed, as also the perioperative risks ofdeveloping an MI, pulmonary embolism, or loss of life The technical details

of the procedure should be explained and informed consent obtained

REFERENCES

1 Rosenthal RA, Zenilman ME, Katlic MR Principles and Practice of Geriatric Surgery.

New York: Springer, 2001.

2 Rogers MC, Tinker JH, Covino BG, et al Principles and Practice of Anesthesiology.

New York: Mosby, 1993.

3 Goldman L Cardiac risk in noncardiac surgery: an update Anesth Analg

80:810–820, 1995.

4 Mangano D, Goldman L Preoperative assessment of patients with known or

sus-pected coronary disease N Engl J Med 333:1749–1756, 1995.

Trang 36

5 Norton LW, Stiegmann GV, Eiseman B Surgical Decision Making Philadelphia,

PA: W.B Saunders, 2000.

6 Smetana G Preoperative pulmonary evaluation N Engl J Med 340(12):937–944,

1999.

7 McFalls EO, Ward HB, Moritz TE Coronary-artery revascularization before

elec-tive major vascular surgery N Engl J Med 351:2795–804, 2004.

8 Schwartz LB, Bridgman AH, Keiffer RW Asymptomatic carotid artery stenosis

and stroke in patients undergoing cardiopulmonary bypass J Vasc Surg

21:146–153, 1995.

9 Nyhus LM, Baker RJ, Fischer JE Mastery of Surgery New York: Little, Brown and

Company, 1997.

10 McAnulty GR, Robertshaw HJ, Hall GM Anesthetic management of patients

with diabetes mellitus Br J Anaesth 85:80–90, 2000.

11 Lefor AT Perioperative management of the patient with cancer Chest

115:165S–171S, 1999.

12 Tiret L, Desmonts JM, Hatton F, et al Complications associated with anesthesia:

a prospective survey in France Can Anaesth Soc J 33:336–344, 1986.

13 Yancick R,Wesley MN, Ries LA, et al Comorbidity and age as predictors of risk for early mortality of male and female colon carcinoma patients based study.

Cancer 82:2123–2134, 1998.

14 Pinholt EM, Kroenke K, Hanley JF, et al Functional assessment of the elderly: a

comparison of standard instruments with clinical judgment Arch Intern Med

147:484, 1987.

15 Dzankic S, Pastor D, Gonzalez C, et al The prevalence and predictive value of

abnormal preoperative laboratory test in elderly patients Anesth Analg

93:301–308, 2001.

16 Kearon C, Hirsh J Management of anticoagulation before and after elective

surgery N Engl J Med 336:1506–1511, 1997.

Trang 37

TRAUMATIC INJURY

Kumash R Patel, MD Steven N Vaslef, MD, PhD

HISTORIC PERSPECTIVE

Trauma has been a part of humanity since before the dawn of civilization and

is not isolated to only the human race Traumatic events occur in all species onearth and the known universe Despite this obvious logic, the ﬁrst recording of

a traumatic event being treated is traced back to the ancient Egyptians At thegreat pyramid at Giza, mummies were found with splints on partially healedfractures of the radius and ulna and healed ends of amputations These mum-mies were dated back to 2465 B.C Formal treatment of injuries was evidenced

in the Edwin Smith Papyrus,1 dating to 1600 B.C (Fig 2-1) These papersdescribe 48 surgical cases of treated wounds to the head, neck, shoulders, chest,and breasts Avicenna’s Canon of Medicine written in 1012 is the next majortext on treatment of injuries, in which he describes, “There are three principles

to follow when treating loss of continuity in fleshy tissues (1) Stabilize the partwhich is insufficiently firm, arrest the bleeding, and if there be a dischargestrive to reduce its amount (2) Make the immobilized part consolidated byadministering appropriate medicines and suitable articles of food (3) Preventsepsis as much as possible If all three cannot be achieved, concentrate on thetwo that can You know how the arrest of bleeding is achieved Consolidation

of the part is secured by opposing the edges of the wound and by applying iccant remedies and by taking agglutinative food.”1These tenets establishedthe basic guidelines for treating not only traumatic wounds, but also mostpathologic diseases This knowledge continued to accumulate over the yearsuntil the ﬁrst successful trauma resuscitation occurred in London on July 16,

des-1774 A 3-year-old child had fallen on the ﬂagstones and had been pronounceddead until an apothecary arrived on the scene 20 min later and proceeded todeliver electric shocks via a portable electrostatic generator The child regained

a pulse and respiration and eventually recovered fully.1

Despite these advances that have been recorded through history, moderntrauma care originated with Dominique Jean Larrey He was the physician to

Trang 38

the French army who in 1797 designed the ambulance volante These

fly-ing ambulances were horse drawn wagons that carried the wounded fromthe battlefield to a base hospital, the first mobile army surgical hospital(MASH), a self-contained United States Army military unit This improvedtreatment and survival, being able to treat the wounded immediately ratherthan waiting for the end of the battle He also developed the concept oftriage during this time “The best plan that can be adopted in such emer-gencies, to prevent the evil consequences of leaving soldiers who are severelywounded without assistance, is to place the ambulance as near as possible tothe line of the battle, and to establish headquarters to which the wounded,who require delicate operations, shall be collected to be operated on by thesurgeon general Those who are dangerously wounded should receive thefirst attention, without regard to rank or distinction Those who are injured

to a less degree may wait until their brethren-in-arms, who are badly lated, have been operated and dressed, otherwise the latter would not sur-vive many hours, rarely until the succeeding day.”1

muti-With these foundations, trauma care evolved over the next two centuriesinto an intricate system of care that is universally adopted As medicalknowledge improved and research revealed the hidden truths of human

Figure 2-1 The Edwin Smith Papyrus, ca 1600 B.C., is the oldest known text describing treatments of injuries.

Trang 39

physiology, so did trauma care Collectively, the knowledge became advancedtrauma life support.

MECHANISMS OF INJURY

With the discussion of trauma and its associated injuries, consideration andunderstanding to the mechanism must be achieved to properly care for thepatient and the injuries that are present These injuries result from energytransfer based on the laws of motion and energy Since energy cannot be cre-ated or destroyed and objects have both stationary and mobile energy, it can

be deduced that the force generated in a traumatic event is transferred to thepatient resulting in various soft tissue and osseous injuries This transfer of

energies leaves two types of cavities On initial impact, the force pushing the tissue and the cellular particles create a temporary cavity Once the forces

have dissipated, the tissues will recoil back to their previous positiondepending on the amount of elasticity and compliance they possess This

process occurs in a fraction of a second A permanent cavity is noticed when

the tissue has the inability to recoil due to destruction or crushing Both these

cavities occur due to two main types of mechanisms: blunt and penetrating.2

Blunt Trauma

Blunt trauma leads to compression, shear, and overpressure injuries

Compression injuries occur due to the force crushing the cells that it comes

into contact with Shear injuries appear from an organ accelerating or

decel-erating at a different velocity than the surrounding tissues or cavity Thestretching and rupturing of surrounding tissues when excessive pressure is

placed on the tissue cause overpressure injuries.2

Causes of blunt trauma are categorized into motor vehicle crashes,

pedestrian injuries, falls, and assaults Motor vehicle crashes are associated

with frontal, lateral, rear, off-center, rotational, and ejectional collisions.2

Pedestrians struck by a motorized vehicle sustain injuries that are associated

with multiple mechanisms and multiple points of force The initial impact

is followed by a fall on another impact point These types of mechanisms

potentially lead to many occult injuries; therefore, a high index of suspicionshould be maintained Falls occur from various heights, leading to variousamounts of force on impact and variable injury patterns Once again, a high

index of suspicion needs to be maintained for occult injuries Assaults come

in a myriad of types and sizes, but are generally more localized than theother mechanisms mentioned Injuries are isolated to the area of impact, forthe most part It must be kept in mind that any of these mechanisms canoverlap into penetrating trauma (Fig 2-2), depending on if an object vio-lated the exterior barrier to enter the soft tissue in the process of the blunttrauma

Trang 40

Penetrating Trauma

Penetrating trauma encompasses those of bullet/missile injuries and stabinjuries from various objects (Fig 2-3) These injuries lead to direct tissuedestruction, various sizes of temporary cavities, and a more permanent cavity.The amount of tissue destruction is dependent on the type of object, its size,and the velocity at which the object was traveling The density of the tissuethe object interacts with will also affect cavity formation As the object movesthrough the tissue, energy is transferred to the tissue The tissue in contactwith the object is crushed and destroyed while the surrounding tissue isstretched all along the path of the object until the force is dissipated and thetissue recoils.2

Stab injuries will have very small temporary cavities created as the object

is entering the tissue, but will have a permanent cavity dependent on thesize of the object and the velocity it was traveling when entering the tissueplanes Bullets and projectile missiles, on the other hand, will create larger

Figure 2-2 Combined blunt and penetrating mechanisms

of injury in a patient who was impaled by a metal fence

post The post is seen entering the upper abdomen and

exiting the left ﬂank.

Định dạng
Số trang	434
Dung lượng	4,67 MB