Page 1536 - Hall et al (2015) Principles of Critical Care-McGraw-Hill

CHAPTER 111: Preoperative Assessment of the High-Risk Surgical Patient 1055

includes sedation and analgesia goals, patients risk being sedated with- complications. Clearly, patients who require emergent surgery should
out analgesia. These patients are at high risk for postoperative delirium. proceed immediately to the operating theatre without delay for cardiac
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Postoperative delirium requires a multimodal treatment strategy. While testing. Patients deemed to be in the high-risk group (those who suffer
haloperidol is sometimes considered, the evidence for improved from unstable coronary artery disease [CAD], decompensated conges-
9
outcomes in those treated with this medication is lacking. Pretreating tive heart failure [CHF], severe valvular disease, and unstable arrhyth-
patients at risk for delirium has had limited success. 10 mias) should have their noncardiac surgery delayed for full cardiac
Identifying at risk patients allows the surgeon caring for postoperative evaluation and treatment.
patients to reduce the risk for delirium. This is done by ensuring that It is the group of patients in the intermediate risk category who will
environmental, medical, and pharmacological factors favor recovery. benefit most from the investigations described below, in an effort to
Examples of such measures include ensuring the patient has appropri- further elucidate the extent of their underlying cardiac disease and to
ate vision and hearing aids in place, controlling noise and lighting that attempt to quantify and possibly reduce the perioperative risks before
affect sleep-wake cycles, ensuring adequate pain control, treating of the commencement of the surgical procedure.
dehydration, appropriate nutrition, and avoiding polypharmacy. Testing becomes more important as patients face intermediate-
or high-risk surgery without good preoperative functional capacity.
ASSESSMENT OF CARDIAC MORBIDITY Patients who suffer from functional limitation due to surgical disease
FOR NONCARDIAC SURGERY may mask important cardiorespiratory disease. In addition, North
America and many other Western countries are in the midst of an
Our aging population, rising rates of obesity, and type II diabetes suggest obesity epidemic. The US Department of Health and Human Services
that more patients presenting for noncardiac surgery will have diag- suggests that most American citizens lead sedentary lives. Forty percent
nosed or clinically suspected ischemic heart disease and thus increased of survey respondents do no leisure physical activity whatsoever. The
risk for perioperative complications. Using multivariate analysis of 1001 lack of symptoms in this large segment of the population results from
consecutive patients presenting for noncardiac surgery, Goldman and “auto–β-blockade.” The patient never achieves in their activities of daily
associates developed an index for perioperative risk (cardiac risk index) living enough physiologic challenge to reveal their disease.
based on clinical, electrocardiographic (ECG), and routine biochemi- Without symptoms of CHF, the possibility of complete left ventricle
cal parameters. The strongest predictors of cardiac morbidity were (LV) systolic decompensation is low. Routine LV function studies by
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the severity of coronary artery disease, a recent myocardial infarction echocardiography are contraindicated. The question remains: “Does this
(MI), and perioperative heart failure. Detsky and coworkers reworked patient have ischemic risk?” In the setting of patients who cannot exercise
the scoring system to allow for broader applicability and less depen- or do not have the physical fitness needed for exercise stress testing, the
dence on clinical examination findings. At present, the standard for ACC/AHA suggest nuclear medicine perfusion studies or stress echocar-
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perioperative cardiac risk assessment combines surgery specific risk, the diography. Both studies also offer the clinician insight into LV function.
Eagle criteria (Table 111-4), and medical risk (Revised Lee cardiac risk The increasing availability of echocardiography has allowed the
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index). The Lee index also includes surgical risks as one of the vari- diagnosis of valvular disease at a rate much higher than in the era of
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ables, however only considers suprainguinal vascular surgery to be high Goldman and Detsky where clinical examination findings defined risk.
risk as opposed to Eagle who considers all vascular surgery risky. Low An increasingly mobile global population results in the presentation of
risk is defined as less than 1% possibility of perioperative cardiac com- diseases such has rheumatic mitral stenosis, considered uncommon to
plications. High-risk patients have a predicted risk of greater than 10%. Western-born patients. Recent publications on perioperative antibiotic
In 2007, the American College of Cardiology and the American Heart coverage have addressed the evolving science of endocarditis prevention.
Association published their guidelines for preoperative assessment. In 2006, the enigma of “mitral valve prolapse without mitral valve regur-
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The guidelines were quickly updated only 2 years later to reflect new gitation” was a Class III recommendation for antibiotics. The update
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perioperative β-blockade information. 16 that followed 2 years later concluded even more strongly that there were
Their conclusion was that patients in the low-risk category may no Class I indications for endocarditis prophylaxis. The committee did
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proceed directly to surgery with an expectation of a low rate of cardiac recognize that in certain very high-risk populations (previous endocar-
ditis, prosthetic heart valves, valvulopathy following cardiac transplanta-
tion, and certain congenital heart disease patients) antibiotic prophylaxis
TABLE 111-4 Eagle Criteria: Surgery Specific Risk for Cardiac Complications “would be reasonable” but with a weaker IIa recommendation. The
High risk (>5%) highest risk of bacteremia is attributed to dental surgery or surgery with
gingival manipulation. Endoscopy was considered low risk.
Emergency surgery
Vascular surgery RISK MODIFICATION
Prolonged operation ■
Large fluid shifts or blood loss PREOPERATIVE CORONARY REVASCULARIZATION
One would expect that if a patient who faces high-risk noncardiac
Intermediate risk (1%-5%)
surgery is known to have coronary artery disease, revascularization
Carotid endarterectomy should improve outcome. Early recommendations for preoperative
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Head and neck surgery coronary artery bypass grafting (CABG) were based on retrospec-
tive data, and either utilized historical controls or did not include the
Intraperitoneal or intrathoracic surgery
mortality associated with CABG itself. Recently, several trials have
Orthopedic surgery examined revascularization through percutaneous procedures as well
Prostate surgery as sternotomy. The CARP trial randomized over 500 patients to have
coronary revascularization or not prior to elective surgery. There were
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Low risk (<1%)
no differences between groups in terms of short-term or long-term
Endoscopic procedures outcome. This was followed by other trials which attempted to address
Superficial procedures some relative weaknesses of CARP and drew the same conclusions. It
Cataract surgery is difficult to dispute that if the patient has an independent reason for
urgent coronary revascularization such as left main coronary artery
Breast surgery disease or continued ischemia following myocardial infarction, coronary

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