Page 1537 - Hall et al (2015) Principles of Critical Care-McGraw-Hill

1056 PART 10: The Surgical Patient

revascularization should precede elective noncardiac surgery. Present before other signs of ischemia become obvious. TEE has been advocated
evidence would suggest that if important but noncritical coronary artery to detect intraoperative ischemia, and has been shown to have superior
disease is identified, preoperative revascularization will delay access to sensitivity and specificity (sensitivity 75%, specificity 100%) in compari-
noncardiac surgery without definite benefit. In the setting of oncologic son to two-lead ECG (sensitivity 56%, specificity 98%) and pulmonary
surgery and major vascular surgery, delays may result in important pro- capillary wedge pressure (sensitivity 25%, specificity 93%). A larger
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gression of disease or death. study (224 patients) confirms that TEE is frequently influential in guid-
■ PERIOPERATIVE β-BLOCKADE ing clinical decision making. In comparison to two-lead ECG and PAC,
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intraoperative TEE was the most important intraoperative guiding factor
Mangano’s important and heavily cited trial randomized patients for in decision making for anti-ischemic therapy, fluid administration, and
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major surgery including vascular surgery to be β-blocked with atenolol. vasopressor or inotrope administration. The technique itself requires
He demonstrated a decrease in cardiac mortality as well as all-cause expensive equipment and specialized training. Even at centers where TEE
mortality. Studies that followed supported his conclusions and led to is standard of care for cardiac anesthesia, the resource is not routinely
enthusiastic embrace of perioperative β-blockade. available for noncardiac surgery patients. New miniature, disposable
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The POISE study, a multicenter placebo-controlled trial of fixed technology may allow greater utilization. No guidelines have suggested
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metoprolol dosing for patients facing intermediate- and high-risk surgery Class I indications for TEE in the noncardiac surgery population.
Mangano’s findings vis à vis cardiac morbidity. However, the all-cause ■ RESOURCE ALLOCATION
with at least one clinical risk factor for coronary artery disease echoed
mortality for patients who received metoprolol was higher due to the If aggressive hemodynamic monitoring in the ICU is responsible for
increased rate of stroke. Concluded differently, the β-blockade of inter- the improved survival of patients with ischemic heart disease following
mediate-risk patients may cause harm. noncardiac surgery, the financial implications are staggering. In Rao’s
Without question, cessation of β-blocker therapy preoperatively leads study, more than 1300 ICU days of care were required to bring about a
to poorer outcome. Equally harmful is the indiscriminate β-blockade 2.4% reduction in the reinfarction rate. However, if admission criteria
of surgical patients without strong evidence of coronary artery disease. were restricted to congestive heart failure, angina plus congestive heart
Patients undergoing vascular surgery, particularly open surgery above failure, or angina plus hypertension, this would account for almost
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the inguinal ligament, should be considered for titrated β-blockade if 80% of the perioperative infarctions, and reduce ICU days to <300.
they have known coronary artery disease and have two or more clinical Studies have suggested that most perioperative myocardial infarctions
risk factors. occur within the first 2 postoperative days suggesting a shorter period
■ INTENSIVE PERIOPERATIVE MANAGEMENT of monitoring may be sufficient.
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■
The rationale for using aggressive perioperative medical intervention to TYPE OF SURGERY: TYPE OF ANESTHETIC
reduce cardiac risk is compelling. Many of the major cardiac risk factors As discussed previously, Eagle recognized that noncardiac operations
such as congestive heart failure, myocardial ischemia, and dysrhythmias may be divided into those that are likely to provoke perioperative
are detectable and amenable to therapy. Factors contributing to oxygen ischemia and those that do not increase the risk of ischemia above
supply and demand balance beyond β-blockade would include appro- normal. Major vascular procedures involving aortic cross-clamping
priate treatment of hypertension, diagnosis and treatment of anemia, and infrainguinal arterial bypass carry a high risk of postoperative
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and appropriate treatment of pulmonary disease. Inpatient optimization ischemia, as do major abdominal and thoracic procedures. Orthopedic
and resuscitation have not led to changes in outcome. A multicenter procedures such as total hip arthroplasty have a lower incidence of
randomized trial of the use of the pulmonary catheter–derived hemo- cardiac morbidity, and are deemed intermediate risk. Peripheral non-
dynamic goals in almost 2000 high-risk patients undergoing elective vascular procedures such as transurethral resection of the prostate, an
abdominal, thoracic, vascular, and major orthopedic surgery showed no operation frequently performed in patients with coexisting coronary
benefit over standard care. 23 artery disease, are associated with a low incidence of perioperative MI. 36
■ PULMONARY ARTERY CATHETER coagulant response, which may be implicated in the development of
Major surgery is associated with an intense sympathetic and pro-
There is no indication for routine use of the pulmonary artery catheter myocardial ischemia. These neurohumoral responses to surgery may
be diminished with the use of epidural anesthesia and analgesia (EAA)
(PAC) to aid decision making for the high-risk surgical patient. Dr extending into the postoperative period. Stress-mediated release of
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Swan, in an elegantly written review in 2005 stated quite strongly: “The hormones such as cortisol, antidiuretic hormone, and catecholamines
PAC is a diagnostic device only and has no therapeutic role.” (authors’ is blunted by epidural anesthesia. In addition, postoperative pain may
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emphasis) The PAC-man trial, a large prospective cohort study of contribute to tachycardia and resultant subendocardial ischemia. Early
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mixed medical and surgical patients in the ICU showed no improve- studies showed a dramatic reduction in cardiac complications in patients
ment in outcome in those patients with pulmonary artery catheteriza- treated with EAA in comparison to general anesthesia (GA) alone. This
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tion. Meta-analyses published in JAMA and the Cochrane Database of opinion was further upheld by a large systematic review of relevant trials
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Systematic Reviews echo these findings. Even more damning, clinicians of epidural or spinal anesthesia versus GA over the past 30 years, which
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may be misinterpreting catheter-derived data at a high rate. Worse showed a statistically and clinically significant reduction in mortality
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yet, clinicians may be subjecting their patients to the risk of catheter and morbidity after surgery. This retrospective work was prospectively
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insertion and not using all the information available. The authors do tested by a large (915 patients) randomized controlled trial of high-risk
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not question the value of identifying right heart failure or pulmonary surgical patients who either received EAA (intraoperatively and up to
hypertension in surgical patients. Important changes to anesthesia and 72 hours postoperatively) with GA or GA alone with intraoperative and
surgical care can be made to favor hemodynamics in that setting. Still, postoperative opioids as the mainstay of the analgesic regimen. The
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given the paucity of data supporting its use and given a known rate of group observed no reduction in mortality or cardiac morbidity between
serious complications, Swan’s catheter should be reserved for very, very groups. The only clinical benefit documented was a reduction in post-
few patients. operative respiratory failure. However, the authors commented that 15
■ TRANSESOPHAGEAL ECHOCARDIOGRAPHY epidurals were required to prevent one episode of respiratory failure.
They also commented that in no cases were there any serious com-
Transesophageal echocardiography (TEE) is a sensitive marker of myo- plications with catheter placement or postoperative problems directly
cardial ischemia, often revealing segmental wall motion abnormalities attributable to the placement of the epidural.

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