Improved Outcomes in Colon and Rectal Surgery part 2 ppt

PreoPerative risk assessment using scoring systems Scoring systems assess the patients’ risk for morbidity and mor-tality taking into account the kind of planned surgical procedure and

Foreword

In Improved Outcomes in Colon and Rectal Surgery, Drs

Whitlow, Beck, Margolin, Hicks, and Timmcke have assembled

a knowledgeable, expert, and distinguished group of

contribu-tors who additionally have flavored their contributions with their

practical experience and “how I do it” approaches This volume

is the third in a series dealing with improving outcomes,

avoid-ing complications, and in general improvavoid-ing the lot of patients

who require surgery for conditions of the large bowel, rectum,

and anus

The stated objective of guiding less experienced surgeons in

avoiding the pitfalls of both commonly encountered

complica-tions and those of rarer occurrence is well met in this volume It

should be in the library of all neophyte surgeons and deserves to

be read even by experienced practitioners

The field of colon and rectal surgery is a dynamic one with endo-scopic and open surgery procedures at a mature stage With con-stantly improving laparoscopic techniques, robotic surgery and other modalities only dreamed about in the past requiring every surgeon

to continue to learn and improve this book fills a visible need

I congratulate the editors and contributors for assembling an extremely useable and timely text

J Byron Gathright, Jr MD

Chairman Emeritus Department of Colon and Rectal Surgery

Ochsner Clinic New Orleans, Louisiana

USA

Eric L Marderstein, Siyamek Neragi-Miandoab, and Conor P Delaney

challenging case

A 65-year-old hypertensive male smoker requires a low anterior

resection for treatment of an upper rectal cancer A CT scan of

the chest, abdomen, and pelvis does not show any distant

meta-static spread and his carcinoembryonic antigen is normal What

additional preoperative laboratory studies and adjunctive testing

are indicated?

case management

A complete history and physical examination is perhaps the

single most important step for guiding preoperative

prepa-ration If a cardiac review of systems indicates no symptoms

of ischemia at a high workload, and an electrocardiogram is

normal then no further cardiac testing is necessary A complete

blood count is indicated because the underlying disease can

cause anemia and serum chemistries are indicated because of

the patient’s hypertension Although routine laboratory

test-ing is not indicated for most procedures, for patients older

than 60 due to undergo major surgery, they are reasonable in

many situations If there is no suggestion of bleeding

abnor-malities or liver disease on history and physical examination

then coagulation studies are not required Pulmonary function

testing, unless the patient has significant

pulmonary-attribut-able shortness of breath or extreme oxygen dependence, is not

necessary The patient should be counseled to stop smoking

because it may prevent postoperative pulmonary

complica-tions, although several weeks of smoking cessation is required

to obtain measurable benefit

introduction

Part of the attraction of colorectal surgery is the diversity of

dis-eases, patients, and procedures that the surgeon sees on a routine

basis On one day a surgeon can perform several small outpatient

anorectal procedures on relatively healthy patients, followed the

next day by several major complex intraabdominal operations on

frail elderly patient with significant comorbidities Such variety

underscores the importance of the preoperative evaluation in

identifying preexisting medical conditions and determining their

effect of the proposed procedure Knowledge of how preexisting

medical conditions can result in certain patterns of postoperative

complications helps to guide the preoperative evaluation This

chapter’s recommendations regarding laboratory investigation

and additional testing are, when possible, based on published

evidence of their clinical efficacy and cost-effectiveness As a

general rule, ordering a myriad of specialized tests or routine

laboratory batteries is expensive and provides low yield Instead,

testing is designed to quantify the magnitude of the preexisting

medical conditions so they can be optimized in the pre-, intra-

and postoperative period to maximize the chance of a successful

outcome

history and Physical examination

A thorough history includes past and current medical and surgical history, medications, allergies, family history, functional history, and review of systems History and physical examination are generally more important than laboratory data in the develop-ment of a treatdevelop-ment plan for anesthesia Young healthy patients with an unremarkable history and examination may not need any anesthesia evaluation for moderate size procedures The overall risk of surgery is extremely low in healthy individuals and no additional benefit is gained from more complex evaluations.(1)

If major surgery is planned, or if patients are elderly or have high levels of comorbidity, a preoperative anesthesia consult is war-ranted and appropriately required at many institutions While the surgeon needs to play an active role in preoperative risk assess-ment, it is often very helpful to have an anesthesia consultation

to evaluate the patient solely from the standpoint of surgical risk Coordination and cooperation between surgeons and anesthe-siologist is essential to avoid unnecessary delays and surprises before the surgery A patient self-administered questionnaire on the complexity of their past medical history can act as an effective primary screening tool to stratify patients for further assessment before surgery.(2) Evaluation is performed with a combination

of history, physical examination, and selected investigations In

a large prospective clinical-epidemiological study, Arvidsson and colleagues found that a standardized assessment before surgery,

by a combination of questionnaires, interview, physical exami-nation, and selected laboratory testing identified a high propor-tion of patients who were likely to suffer an adverse event in the postoperative period.(3)

PreoPerative tests

Thorough preoperative assessment of patients can minimize

or prevent postoperative complications.(4) Selective labora-tory studies can be useful, but routine laboralabora-tory tests are often unnecessary.(5, 6) Ordering a battery of routine preoperative laboratory studies leads to inefficient clinical practice and is not cost-effective.(7) In one large study, only 0.22% of routine pre-operative laboratory studies revealed abnormalities that might influence peroperative management.(8) Tests ordered in screen-ing panels are frequently not acted upon before surgery, thereby creating additional medicolegal risk.(8) When laboratory tests are felt to be necessary, it is probably safe to use test results that were performed and were normal within the past 4 months as preop-erative tests unless there has been an interim change in clinical status Anemia is present in approximately 1% of asymptomatic patients.(8) However, anemia is common following major sur-gery and the preoperative hemoglobin level predicts postopera-tive mortality.(9) A baseline hemoglobin level in patients who are undergoing major surgery that is expected to result in significant blood loss is useful in postoperative management to differentiate

improved outcomes in colon and rectal surgery

between acute or chronic blood loss The frequency of significant

unsuspected white blood cell or platelet abnormalities is also low

(10) Unexpected electrolyte abnormalities are uncommon and

routine electrolyte determinations are not recommended unless

the patient has a history that increases the likelihood of an

abnor-mality.(8) Premenopausal females at risk should undergo a urine

or blood test for beta-HCG to determine if they are pregnant so

that appropriate precautions are taken during surgery if still

indi-cated This practice is codified at many institutions to improve

safety and reduce medical liability Nonetheless, it is all too

com-mon for a lapse in obtaining a pregnancy test to result in a lengthy

delay in the start of surgery Routine urinalysis to detect disease

(proteinuria, glucosuria, bacteruria), however, is not indicated

PreoPerative risk assessment using

scoring systems

Scoring systems assess the patients’ risk for morbidity and

mor-tality taking into account the kind of planned surgical procedure

and the type of anesthesia.(11) These systems generally use data

acquired during prehospital and in-hospital care, while

inclu-sion of the severity of the planned procedure might improve the

predictive value of these systems.(12, 13) Others have tried to

predict the risk anecdotally, suggesting that a surgeon’s general

feeling and personal experience are a good indicator of

subse-quent outcome.(14) Scoring systems can be helpful in

coun-seling the patient and setting their expectations preoperatively

beyond clinical intuition In addition, well-constructed scoring

systems can be used to compare hospitals and surgeons while

controlling for the known influence of preoperative risk factors

for poor outcome.(15)

American Society of Anesthesiologists (ASA) Classification

The ASA classification system (Table 1.1) has been developed by

anesthesiologists to evaluate patients’ preexisting morbidities

and operative risk The system is easy to use and is based on

his-tory, physical examination, and the physician’s experience and

it requires no tests.(16, 17) ASA class has been shown to

corre-late with perioperative mortality and morbidity, as well as with

perioperative variables such as intraoperative blood loss,

dura-tion of postoperative ventiladura-tion, and duradura-tion of intensive care

unit stay.(18–20) The severity of operative procedure, higher

ASA class, symptoms of respiratory disease and malignancy

are predictive of postoperative morbidity.(13) Disadvantages

to use of the ASA score is that its accuracy depends on the

subjective clinical judgment and experience of the attending

anesthesiologist

POSSUM (Physiologic and Operative Severity Score for enUmeration of Mortality and morbidity)

POSSUM was developed through multivariate analysis prima-rily to permit surgical audit for assessment of quality of care.(21)

It calculates expected death and expected morbidity rates based

on 12 physiological variables and six operative variables each of which are scored 1, 2, 4, or 8 (Table 1.2).(22) POSSUM was devel-oped as a scoring system for audit, so other factors may need to be considered when using POSSUM for risk assessment of patients for surgery

One concern with POSSUM has been that it may over predict mortality and morbidity rates by up to six times with a mini-mum mortality of 1.1% POSSUM was modified by Portsmouth

to P-POSSUM using a different calculation to reduce the over-prediciting bias.(23) While some studies found that both scoring systems overpredicted mortality rates for vascular sur-gery patients (24, 25), others found that P-POSSUM was a bet-ter predictor of mortality and morbidity than POSSUM for vascular (26) gastrointestinal surgery (27), and laparoscopic colorectal surgery (28)

The CR-POSSUM (Table 1.3) was a modification of POSSUM designed to assess risk of colorectal procedures A retrospec-tive multivariate analysis was performed on more than 6,000 patients operated on in the United Kingdom between 1993 and 2001.(29) The overall mortality for the series was 5.7% and the CR-POSSUM was more accurate than POSSUM in their valida-tion patient set The advent of laparoscopic colorectal proce-dures may result in CR-POSSUM also overestimating mortality

A recent report noted that CR-POSSUM overestimated mor-tality in patients undergoing laparoscopic colectomy, but accurately predicted mortality in the subset of patients requir-ing conversion.(30) When these scorrequir-ing systems were applied

Table 1.1 American Society of Anesthesia (ASA) classification

scheme

I Normal healthy patient

II Mild systemic disease

III Severe, noncapacitating systemic disease

IV Incapacitating systemic disease, threatening life

V Moribund, not expected to survive 24 hours

Table 1.2 Parameters for calculation of the POSSUM score.

Age (years) Operative severity Cardiac signs/chest x-ray Multiple procedures Respiratory signs/chest x-ray Total blood loss (ml)

Systolic blood pressure (mm Hg) Presence of malignancy Glasgow Coma Score Mode of surgery Hemoglobin (g/dl)

White cell count (×1012/l) Urea concentration (mmol/l) Na+ and K+ levels (mmol/l) Electrocardiogram

Table 1.3 Parameters for calculation of the CR-POSSUM score.

Physiological Parameters operative Parameters

Age (years) Operative severity Cardiac signs/ chest x-ray Urgency of surgery Pulse rate Peritoneal soiling Systolic blood pressure (mm Hg)

Urea concentration (mmol/l)

Presence of malignancy Hemoglobin (g/dl)

preexisting conditions

to data from a series of U.S hospitals; the CR-POSSUM was

the most accurate variant, but overestimated mortality by more

than twofold.(31)

National Surgery Quality Improvement Project (NSQIP)

NSQIP was initially started as a way to measure quality of surgical

care at Veteran’s Administration hospitals but the methodology

has spread to the private sector and is embraced by the American

College of Surgeons (ACS-NSQIP) It is a nationally validated,

risk-adjusted, outcomes-based program to measure and improve

the quality of surgical care.(32) The program employs a

pro-spective, peer-controlled, validated database to quantify 30-day

risk-adjusted surgical outcomes, which allows valid comparison of

outcomes among all hospitals in the program Participating

hos-pitals and their surgical staff are provided with the tools, reports,

analysis, and support necessary to make informed decisions about

improving quality of care A key lesson from NSQIP was

deter-mining what key preoperative variables influence morbidity and

mortality By risk-adjusting the outcomes, morbidity and

mortal-ity can be compared between hospitals without the common

argu-ment “my patients are sicker.” The initial studies were performed

on huge numbers of patients with multivariate analysis ranking

certain preoperative conditions/variables as particularly

influen-tial on postoperative complications and mortality Albumin, ASA

class, disseminated cancer, emergency surgery, age, blood urea

nitrogen, functional status, weight loss, and “do not resuscitate”

order are consistently the most important variables in the analysis

(33) The program was initially validated using a range of

surgi-cal procedures, but subsequent publications have used the same

methodology to study particular types of operations For example,

complications and mortality after colectomy for colorectal cancer

depends on identical preoperative variables as the initial validation

set.(34) The program is well respected because a great emphasis

is placed on data integrity and follow-up to identify preoperative

and postoperative events

documentation

As an increased emphasis is placed on tracking and

report-ing of complications it is critically important to the surgeon

to document well For risk-adjusted complications to be valid,

preoperative comorbidities must be identified and noted in the

medical record Without this, the surgeon will not have

justi-fication for elevated complication rates based on preoperative

illness This will become more important as DRG classification,

and therefore institutional technical reimbursement, becomes

dependent on diagnosis documented at the time of admission

in the near future

cardiovascular disease

Perioperative cardiac complications are among the most feared

of surgical complications because they can result in death Their

severity spans a wide range from asymptomatic increase in

car-diac enzymes to fatal massive myocardial infarctions The goal of

preoperative cardiac evaluation is to quantify the likelihood of

a perioperative cardiac event taking into account patient factors

and the proposed operative procedure The concept of “cardiac

clearance” is flawed and should not be used In reality, a patient

with a very low cardiac risk is not immune to perioperative cardiac events and a patient with known severe coronary artery disease

is by no means guaranteed to have a fatal myocardial infarction Even in the highest risk patients undergoing complex vascular surgery, the risk of postoperative cardiac events is only 34%.(35) The risk of the proposed procedure must be weighed against the proposed benefit and urgency to be derived from the operation to permit the surgeon and patient decide about the appropriateness

of proceeding with surgery

Multiple models have been devised to estimate perioperative cardiac risk The Goldman risk model was an early and accepted model for pure determination of cardiac risk for surgery (36) The system is easy to use and utilizes relative weighting of risk factors; however, it was designed several decades ago and has not been updated for modern practice Two more modern predic-tive models include those proposed by Detsky et al (37) and Lee

et al (38) The Lee index identified six independent predictors of cardiac complications: high-risk surgery (procedures with a 5%

or higher risk of cardiac complications—including prolonged intraperitoneal operations), history of ischemic heart disease, his-tory of congestive heart failure, hishis-tory of cerebrovascular disease, diabetes, and preoperative serum creatinine >2.0 mg/dL Patients with 0, 1, 2, or 3 or more criteria were found to have a rate of major cardiac complications of 0.5%, 1.3%, 4%, and 9% respectively The receiver operating curve generated on a validation cohort of patients was higher for the Lee index versus the Goldman index and Detsky’s model, indicating higher predictive power.(38) The American College of Cardiology (ACC) and American Heart Association have issued evidence-based guidelines for the evaluation of patients for noncardiac surgery They are available at their website (www.acc.org), the National Guideline Clearinghouse (www.guidelines.gov), and in print.(39)

A cardiac history and physical exam is designed to identify unsta-ble coronary syndromes, prior angina, recent or past myocardial infarction, severe valvular disease, decompensated heart failure, and significant arrhythmias Presence of a pacemaker or implant-able cardioverter defibrillator should be noted Hypertension should be identified and controlled pre-, intra-, and postopera-tively Elevated blood pressure increases myocardial work, stress and oxygen demand Interestingly, a randomized trial was unable

to demonstrate a benefit to delay of surgery for the purpose of con-trol of severe hypertension.(40) Volatile anesthetics and intravenous medications can remedy the hypertension quickly Antihypertensive medications should be taken with a sip of water on the morn-ing of surgery and resumed postoperatively as soon as possible Symptomatic aortic or mitral stenosis should be identified and evaluated preoperatively In certain cases, a valve replacement or percutaneous valvuloplasty will greatly reduce the risk of surgery

A history of orthopnea, dyspnea on exertion, and paroxysmal noc-turnal dyspnea are suggestive of congestive heart failure Pitting ankle edema, rales on auscultation of the chest, jugular venous dis-tention, and an S3 gallop on physical examination all support the diagnosis of heart failure A chest radiograph showing cardiomegaly and prominent pulmonary vascularity is supportive Noninvasive evaluation of ventricular function and optimization of the con-gestive heart failure should be achieved before surgery in such patients

improved outcomes in colon and rectal surgery

In patients with existing cardiac disease, recent changes in

symptoms must be identified Assessment of functional status is

important to determination of preoperative risk If the patient

can-not or does can-not achieve an adequate level of activity in their daily

life it may hide the angina or symptoms they would experience

should they reach that level The surgical stress can cause cardiac

complications in these patients who would appear to be

asymp-tomatic based on preoperative questioning if their functional

status is poor The Duke Activity Status Index was developed as a

way to correlate a patient’s exercise tolerance with activities that

they can perform in daily life.(41) Peak oxygen uptake on exercise

testing correlates very well with the determination by this self- or

physician-administered questions The scale defines these daily

activities in terms of metabolic equivalents (METs) Patients who

cannot reach four METs (equivalent to light housework, climbing

a flight of stairs or walk on level ground at 4 mph) would require

additional investigation if it is necessary to determine whether

they are really asymptomatic or not Patients who can exercise

at a very high MET without symptoms are less likely to harbor

significant cardiac disease

The ACC has defined a stepwise algorithm to preoperative

evaluation of the patient requiring noncardiac surgery Surgery

should be cancelled or delayed unless emergent in patients with

unstable or severe angina, myocardial infarction <1 month prior,

decompensated heart failure, significant arrhythmias or severe

valvular disease.(39) Risk stratification for the type of surgical

procedure includes high (>5% reported cardiac risk),

intermedi-ate (1–5%), or low risk Intraperitoneal procedures are considered

intermediate risk while ambulatory procedures are considered low

risk Laparoscopic intraperitoneal surgery, although associated

with less pain and postoperative fluid shifts, should be considered

intermediate risk because of the potential need for use of an open

approach depending on intraoperative circumstances In patients

undergoing low-risk surgery, no further cardiac assessment is

necessary For patients undergoing intermediate risk surgery,

evi-dence of good functional capacity without symptoms indicates

no further testing is neededbefore surgery If the functional status

is poor or unknown, presence of one or more clinical risk factors

as defined by Lee (history of coronary artery disease, history of

heart failure, history of cerebrovascular disease, diabetes or renal

insufficiency) then options include noninvasive cardiac testing to

further stratify risk if it will change management Alternatively,

the operation can proceed with heart rate control pre-, intra-, and

postoperatively Patients without symptoms and with a normal

cardiac stress test within past 2 years or revascularization in the

past 5 years do not require further evaluation If no clinical risk

factors are present, the operation can proceed

The preoperative electrocardiogram (ECG) is not as

indispen-sable as it once was The prevalence of abnormal ECGs increases

with age.(42) However, multiple studies seem to indicate that the

electrocardiogram alone is a poor independent predictor of

post-operative cardiac complications.(43–45) While ECG abnormalities

indicate an elevated cardiac risk, it loses its independent predictive

power when analyzed with patient clinical characteristics One of

these studies did indicate particular risk for patients with left or

right bundle branch blocks on their ECG.(46) In certain cases, the

ECG may contribute to an incomplete history as previous silent

myocardial infarction is common.(47) A preoperative baseline ECG can be important as a baseline, since it can be of significant impor-tance in identifying postoperative ECG changes.(36) Preoperative dysrhythmias (>5 premature ventricular contractions/min) and P-wave abnormalities are predictive of postoperative dysrhythmias (48) The recommendations of the ACC are less clear on the value

of a preoperative ECG than other clinical issues A preoperative resting 12-lead ECG is recommended for patients with at least one clinical risk factor who are undergoing intermediate risk proce-dures or patients with no clinical risk factors who are undergoing high-risk surgery Additionally, a preoperative and postoperative ECG is not recommended for asymptomatic patients undergoing low risk surgery The quandary lies with the asymptomatic patient planned for intermediate risk surgery If there is any question about the functional status, an ECG is indicated By contrast, if the func-tional status is outstanding and no symptoms are present it could

be argued to omit the test Lee’s Revised Cardiac Risk Index was derived in patients 50 years and older so an arbitrary age cutoff here may be reasonable

Noninvasive evaluation of ventricular function with echocar-diography is indicated in patients with dyspnea of unknown ori-gin, current or prior heart failure with change in symptoms.(37) Routine evaluation of ventricular function is not recommended Preoperative revascularization is generally not indicated before surgery unless it would have been recommended for the patient based on their cardiac evaluation, regardless of whether they had sur-gery planned The Coronary Artery Revascularization Prophylaxis (CARP) trial randomized patients with known coronary artery disease by cardiac catheterization to revascularization versus medi-cal management before elective vascular surgery.(49) The Dutch Echocardiographic Cardiac Risk Evaluation Applying Stress Echo-cardio graphy (DECREASE-V) trial also randomized patients to revascularization or best medical therapy before vascular surgery (50) Both randomized trials failed to show a benefit to revasculari-zation before surgery when optimal medical treatment was applied

If percutanous coronary intervention is indicated and performed before surgery, either angioplasty or bare-metal stents should be used and drug-eluting stents avoided Drug eluting stents have a higher associated restenosis rate when anticoagulation is discontin-ued early If possible, waiting 4 to 6 weeks after stent placement is beneficial because the stent with be at least partially endothelialized and clopidogrel (Plavix) can be stopped If possible, aspirin is to be continued or resumed quickly after surgery

Perioperative treatment with beta-blockers titrated to a heart rate of <70 beats per minute to reduce cardiac risk has been studied

in multiple clinical trials Although some more recent trials have not demonstrated the pronounced benefit of earlier trials on the subject, the aggregate conclusion of the multiple studies suggests benefit with small risk Preoperative beta-blockade is indicated in patients having intermediate risk surgery with one or more clinical risk factors or any patient having vascular surgery It is not indi-cated in patients for low-risk surgery or intermediate risk surgery without clinical risk factors Some authors argue that effective beta-blockade obviates the need for additional cardiac testing in certain intermediate risk patients.(51) Institution of statin-class medica-tion for patients with one or more clinical risk factors undergoing intermediate risk surgery should be considered.(52)

preexisting conditions

Pulmonary disease

Postoperative pulmonary complications (PPCs) are equally

preva-lent and contribute similarly to morbidity, mortality, and length

of stay as cardiac complications.(53) They include atelectasis,

pneumonia, bronchospasm, and respiratory failure (mechanical

ventilation for >48 hours) The American College of Physicians

(ACP) issued guidelines for pulmonary risk stratification

avail-able on their website www.acponline.org and www.guidelines.gov

Several risk factors are known to increase the risk of pulmonary

complications Even when controlling for other comorbid

condi-tions, evidence suggests that increasing age is a risk for

pulmo-nary complications.(51) Congestive heart failure, although not

a pulmonary condition, increases risk for postoperative

pulmo-nary complications Functional dependence defined as need for

assistance from another person or devices to perform activities

of daily living was associated with pulmonary complications.(54)

Impaired sensorium is associated with an increased risk of

pulmo-nary complications While obesity does not seem to be associated

with an increased risk of pulmonary complications, sleep apnea

does appear to confer increased risk.(53) Cigarette smoking greatly

increases the incidence of pulmonary complications compared to

nonsmokers

Procedure-related risk factors increase the likelihood of

pulmo-nary complications Incision location (thoracic, upper abdomen,

lower abdomen) has been shown in several heterogeneous studies

to correlate with pulmonary risk, as well duration of surgery (>2.5

hours in some studies and >4 in others).(53) General anesthesia

and emergency surgery have also been found to be associated

with increased postoperative pulmonary complications

The ACP guidelines suggested that a preoperative chest radiograph

is indicated in patients with known cardiopulmonary disease or those

older than 50 years of age who are undergoing upper abdominal or

abdominal aortic aneurism surgery Routine chest radiography in

all patients has been shown to be associated in many studies with a

very small number of abnormalities that influenced management

and an even smaller number in patients under the age of 50.(55,

56) It is reasonable however to have a low threshold to order the

test in those patients in whom it is more likely to be abnormal than

an unselected population This includes patients with a positive

pulmonary review of systems for conditions such as cough,

dys-pnea on exertion, or recent pneumonia or the presence of chronic

lung conditions such as asthma or pulmonary fibrosis

Pulmonary function testing is an expensive and tricky test to

administer It has a well-established place in the preoperative

workup of lung resection patients, but there is no clear

indica-tion in the preoperative workup of abdominal surgery patients

Evidence from several studies suggests that segregating patients

by forced expiratory volume in 1 s (FEV1) creates groups with

differing pulmonary complication rates from 14.6% up to 31%

in the highest and lowest group respectively.(53) What is lacking

from these studies is the correlation of the spirometry with clinical

history, physical exam and other findings The implication is that

poor preoperative spirometry can be inferred from these

noninva-sive means The few studies that have compared spirometry data

with clinical data have not consistently shown spirometry to be

superior to history and physical examination.(53) The

spirom-etry data do not demonstrate a threshold below which surgery is

prohibitively dangerous In a study of patients with FEV1 < 50% predicted only <15% of patients died or experienced a major pulmonary complication.(57)

Control of acute and chronic pulmonary illness and cessa-tion of smoking can help reduce pulmonary complicacessa-tions.(58) Treatment and clearance of acute pulmonary infection before surgery is recommended Smokers have a four-fold higher risk of pulmonary complications compared to nonsmokers Several stud-ies demonstrate that a 4 to 8 week period of smoking cessation with greatly decrease this risk.(59–61) Anecdotal evidence suggested that stopping smoking too close to the time of surgery would have

a paradoxical increase in pulmonary complications While the sal-utary effect of stopping smoking is difficult to demonstrate until

4 weeks, these same studies do not report a higher complication rate in those who have recently quit.(59, 61) Optimization of chronic obstructive pulmonary disease (COPD) and treating any exacerba-tion with steroids if necessary is advantageous.(56) Laparoscopic surgery, if possible, is recommended as it was shown in meta-analysis

to have a trend toward lower pulmonary complications.(62) Asthma can worsen after surgery Patients with asthma should

be identified preoperatively and their medications reviewed The National Asthma Education and Prevention Program has issued guidelines for management of asthmatics undergoing surgery (available at www.guidelines.gov and in print).(63) Their pre-operative lung function should be optimized to their predicted values or personal best using a short course of steroids if necessary

to achieve this Patients who received >20 mg of prednisone per day for more than 3 weeks in the 6 months before surgery should

be assumed to have suppression of hypothalamic—pituitary— adrenal function and stress dose steroids are indicated The stress dose depends on physicians’ experience, the patient’s condition requiring chronic steroids, the length and dose of preoperative use of steroids The stress dose can be tapered to preoperative dose within 3 days postoperatively

Postoperative care techniques can reduce pulmonary complica-tions Adequate pain control is essential for an effective deep breath-ing program Multiple studies have been performed evaluatbreath-ing various techniques but the consensus guideline indicates that no lung expansion intervention has been shown superior to another but any type of prophylaxis is better than none.(58)

renal disease

The patient with preexisting renal disease presents a special chal-lenge to the surgeon In patients with preexisting renal dysfunction

is important to avoid additional intraoperative or postoperative injury caused by dehydration or toxic agents Adequate urine output is an indication of adequate renal perfusion Obtaining a preoperative urinalysis may identify unsuspected urinary tract infec-tion, diabetes, or renal insufficiency However, routine urinalysis is not recommended preoperatively for most surgical procedures (64) Careful questioning regarding symptoms of dysuria, hesi-tancy, nocturia, and feelings of incomplete evacuation may diag-nose prostatic disease and its complications including early stage renal dysfunction Normal renal function is necessary for the excretion of the nondepolarizing muscle relaxants used for anesthesia and surgery Renal function is also a consideration when choosing postoperative analgesic regimens including nonsteroidal

improved outcomes in colon and rectal surgery

medications such as ketoralac Age, hypertension, and diabetes

may be indications for preoperative selective renal function

test-ing Once renal function is compromised, all medications cleared

by kidney must be dose adjusted in a timely manner and

care-fully monitored if needed Nephrotoxic agents should be avoided

whenever possible Angiotensin-converting enzyme inhibitors

reduce the renal perfusion and should probably be avoided if

possible.(65) Mild to moderate renal impairment is usually

asymptomatic; the prevalence of an elevated creatinine among

asymptomatic patients with no history of renal disease is only

0.2%.(66) However, it increases with age.(67) Dialysis is

neces-sary in 1% of patients who develop acute renal failure; the 30-day

mortality is high in those patients with acute renal failure

com-pared to those with normal renal function.(68, 69) Risk factors

for acute renal failure include advanced age, baseline renal

dys-function, left ventricular dysdys-function, peripheral vascular disease,

and clinical signs of poor cardiac function such as pulmonary

rales.(38, 68)

Patients with end stage renal failure on dialysis require

spe-cial attention Patients in with end stage renal disease often have

concurrent hypoalbuminemia and anemia resulting in poor

wound healing and increased risk of complications Krysa et al

describe a high instance of anastamotic leak in these patients

(70) Decreased leukocyte and immunologic function result in

increased risks of infection and impaired cellular immunity.(71)

Pulmonary edema and uremic pneumonitis may compromise

res-piratory function.(72) Postoperative ileus may be prolonged and

patients with diverticulosis are at increased risk for acute infection

and perforation.(73) Fluid and electrolyte abnormalities occur

rapidly and require intensified scrutiny to maintain balance It is

important to know if the patients make any urine preoperatively,

otherwise alternative strategies from postoperative urine volume,

such as central venous pressure measurement, will be necessary

to ensure adequate tissue perfusion Dialysis can be scheduled on

the preoperative day and again on postoperative day number one

Acute postoperative dialysis can be provided at any time using

the same indications for acute dialysis in a nonpostoperative

patient Dialysis can improve abnormalities of hemostasis that

are caused by platelet dysfunction Abnormal bleeding in dialysis

patients can be improved by platelet transfusion or

administra-tion of desmopressin acetate (DDAVP) increasing the release of

von Willebrand factor from the endothelium

hePatic disease

Operating on patients with significant liver disease is among the

most daunting tasks for the colorectal surgeon Although the

Child-Pugh classification was originally described to assess the operative

risk in patients undergoing shunt surgery for portal

hyperten-sion, it has implications for other abdominal surgery This

classi-fication is a scoring scale designed to quantify liver dysfunction It

utilizes bilirubin, albumin, prothrombin time, presence of ascites,

and presence of encephalopathy to assign points and a subsequent

classification from A to a maximal dysfunction of C In a classic

review of cirrhotic patients undergoing a variety of elective and

emergent general surgical procedures, Child’s A cirrhosis carried a

10% mortality, Child’s B cirrhosis had a 31% mortality, and Child’s

C cirrhosis was associated with a 76% mortality.(74) In a study of

cirrhotic patients undergoing colectomy, the in- hospital mortality was 24% with highest mortality for patients with encephalopathy, ascites, hypoalbuminemia, and anemia.(75)

Suggestion of underlying cirrhosis can be detected at physical examination Scleral icterus, jaundice, spider telangiectasia, and palmar erythema may be present Early cirrhosis is associated with

an enlarged liver while advanced disease will lead to a small shrunken liver Asterixis, or flapping tremor, is a sign of advanced disease Ascites can be detected by physical examination Unexpected liver enzyme abnormalities are uncommon, occurring in only 0.3% of patients in one series.(76) In a pooled data analysis, only 0.1% of all routine preoperative liver function tests changed preoperative management.(77) Severe liver function test abnormalities among patients with cirrhosis or acute liver disease are associated with increased surgical morbidity and mortality, but it is not clear if mild abnormalities among patients with no known liver disease have a similar impact.(78) Clinically significant liver disease would most likely be suspected on the basis of the history and physical exami-nation; thus, routine liver enzyme testing is not recommended.(8)

In addition, the relationship between an abnormal result and the risk of perioperative hemorrhage is not well defined.(77, 79) Patients with liver disease often have disordered and abnormal coagulation Decreased production of clotting factors, especially vitamin K-dependent ones, by the liver will often result in elevated prothrombin times (PT) or partial thromboplastin times (PTT)

In some cases fresh frozen plasma or vitamin K administration can correct these abnormalities, at other times the liver disease

is so severe that the coagulopathy cannot be corrected In addi-tion, patients with cirrhosis may have portal hypertension and splenomegaly, resulting in sequestration and a very low platelet count It is mandatory to monitor platelet count as well as PT, PTT preoperatively so that abnormalities can be corrected Portal hypertension can result in portosystemic varicies resulting

in significant intraoperative bleeding at sites which are technically difficult to manage, such as the splenic flexure and the distal rec-tum Use of alternate energy sources (such as Liga-SureTM, Valleylab, Boulder, CO or Enseal®, SurgRX, Redwood City, CA) may assist in reducing intraoperative blood loss in these challenging patients Abnormal clotting factors may increase the risk of bleeding from hemorrhoidal disease in these patients, or actual rectal varices may

be present

Patients with liver disease are often nutritionally depleted and have a very low albumin They may also have ascites present at sur-gery Although the ascites can be drained at operation, it generally reaccumulates rapidly Our practice is to leave a drain in the abdo-men perioperatively to assist the fascia to seal, so that the ascites will not become tense and may be less likely to breach the incision Fluid and electrolyte disturbances are common in the patient with liver disease including sodium retention, potassium losses, and the development of edema Fluid and sodium restriction, potassium supplementation, and the judicious use of diuretics (spironolac-tone and furosemide) may be necessary

malnutrition

Malnutrition is a frequent preexisting condition in surgical patients Identification of malnourished patients is possible by clinical history, physical examination, and laboratory parameters

preexisting conditions

Malnourished patients, who have lost more than 10% of their

bodyweight in the past 6 months, and have an albumin below 3 g/

dL, have increased complication rates after surgery.(80) A serum

albumin of <3 g/dL, transferrin of <200 mg/dL, and total

lym-phocyte count of <1,200 are consistent with at least some level of

nutritional depletion The enteral route is the preferred route of

improving nutrition as long as there is a functioning

gastrointes-tinal tract There is moderate evidence that improved

preopera-tive nutritional status can improve the postoperapreopera-tive outcome

(81) Severely malnourished patients might benefit more from

nutritional support, although this needs to be provided for

approximately 2 weeks to achieve such benefit.(82) Low body

mass index (BMI) (<20 kg/m2) and hypoalbuminemia (<2.5 g/

dL) are independently associated with increased risk of morbidity

and mortality after surgery Patients with decreased albumin

lev-els are also at increased risk for bleeding, renal failure, prolonged

ventilatory support, and reoperation.(83, 84)

immunocomPromise

The sources of immunocompromise in potential surgical patients

are numerous and may be primary or acquired Primary

immu-nodeficiencies are relatively rare (1/10,000) and will not be

encountered by most practicing surgeons.(85) Acquired

immu-nodeficiencies are very common and range from mild defects to

complete loss of immune function Age, malnutrition, obesity,

malignancy, burns, sepsis, trauma, surgery, anesthesia, blood

trans-fusion, diabetes, renal failure, liver disease, splenectomy, radiation,

and foreign bodies all modify the body’s response to invasion

Drugs including chemotherapeutic agents are probably the most

frequently encountered cause of severe immunocompromise in

surgical patients and are associated with profound neutropenia

The use of filgrastim, a granulocyte colony-stimulating factor,

has been shown to decrease the duration of neutropenia and

the incidence of infection versus controls in patients

undergo-ing chemotherapy for small cell carcinoma of the lung and other

nonmyeloid malignancy (86, 87) Cook et al (88) reported that

neutrophil—lymphocyte ratio (NLR) is an indicator of

postoper-ative complications in colorectal surgical patients in critical care

units An elevated NLR on the first day after an elective colorectal

resection is associated with increased risk of subsequent

compli-cations NLR calculation does not burden the hospital with

addi-tional cost and can be used to identify patients at high risk of

complications.(88)

hiv/aids

When evaluating a human immunodeficiency virus (HIV)

positive patient for surgery it is important to understand the

current state of their disease This can be obtained by checking

for history of autoimmune deficiency syndrome (AIDS)

defin-ing illness and measurdefin-ing a CD4 count and HIV viral load An

absolute CD4 count of <200 or a decreasing ratio of CD4 to

CD8 (normal 1.8–2.2) is associated with severe

immunocom-promise and subsequent risk for viral, fungal, protozoal, and

bacterial infections as well as prolonged wound healing Newer

drug regimens that include combinations of protease inhibitors

and nucleoside analogs have greatly improved the prognosis for

HIV-infected patients.(89)

metabolic disease

Metabolic diseases represent disorders where altered chemical transformation processes have resulted in abnormal release, stor-age, synthesis, or degradation of various protein, carbohydrate, lipid, or other products of metabolic activity Gout is a generic term for a number of genetic and acquired conditions mani-fested by hyperuricemia and the deposition of uric acid crystals

in joints precipitating an acute inflammatory arthritis Acute gouty arthritis often follows a precipitating event Acute gout has been commonly described in the postoperative setting.(90, 91)

It manifests most commonly on the third to fifth postoperative day Treatment consists of joint rest and administration of colchi-cine or non-steroidal anti-inflammatory agents.(92) A thorough past medical history including previous attacks of gout will alert the clinician that the patient is at risk postoperatively At the first early signs of an attack it can be treated quickly Significant delay can result in impaired ambulation secondary to pain which has the potential to prolong ileus and delay recovery

obesity

Obesity has reached epidemic proportions in many areas of the world and obese patients are requiring surgery more and more commonly The BMI is a commonly used relationship to measure obesity and it represents the bodyweight in kilograms divided by the height in meters squared A BMI 18–25 is considered normal while >30 is obese Obesity has been demonstrated to be a risk factor for abdominal surgical wound infection.(93) It has not surprisingly been linked to increased incidence of wound dehis-cence (94), hernia (95), stoma complications (96) Some studies indicate a higher anastomotic leak rate for low colorectal or colo-anal anastamosis in obese patient.(97) Cardiovascular, pulmonary, and thromboembolic complications are more frequent in obese patients, often attributable to their comorbid diseases.(98) Obesity also causes technical difficulties for the surgeon; operative dura-tion and likelihood for conversion were increased in obese patients undergoing laparoscopic surgery.(99) It is reasonable as part of the informed consent process to counsel patients about their elevated operative risk due to obesity If possible, they should be encouraged

to lose additional weight before certain types of surgery where a delay is safe, and indeed may be beneficial (proctocolectomy with pouch-anal anastamosis, some diverticular resections)

The extensive experience with bariatric surgery has taught us that sleep apnea is very common in obese individuals The patient should be questioned for snoring, apneic episodes, arousals dur-ing sleep, or daytime somnolence Physical exam should focus

on evaluation of the airway, neck circumference, tonsil size and tongue volume The American Society of Anestheiologists Task force recommends that if any of these characteristics are present that suggest sleep apnea then the anesthesiologist and surgeon should jointly decide whether to: manage the patient periop-eratively based on clinical criteria alone or obtain sleep studies during the conduct of a more extensive evaluation in advance

of surgery.(100) Postoperatively supplemental oxygen should

be administered continuously to all patients with sleep apnea until they are able to maintain their baseline oxygen saturation while breathing room air Sleep apnea patients should have con-tinuous pulse oximetry monitoring until they are no longer at