PRE-OPportunity Knocks: A Different Way to Think About the Preoperative Evaluation
Am Fam Physician. 2000 Jul 15;62(2):308-309.
As family physicians, we commonly use the annual general assessment of the patient to address preventive health issues. Ideally, we would also reconsider the patient's medical conditions, medications and other functional issues at this time. Often, the visit is too short to address everything. For this reason, the preoperative assessment represents a unique opportunity not only to address risk factors directly related to the upcoming operation, but also to do some “spring cleaning.”
When determining patient risk, we will find nonmodifiable and modifiable risk factors. If the preoperative risk secondary to nonmodifiable factors (such as extremely poor ventricular function) is found to be prohibitive, the difficult decision needs to be made with the patient: does this patient really need this surgery? When modifiable risk factors are present, early evaluation, as suggested by King in this issue's article “Preoperative Evaluation,”1 allows the family physician to act definitively, possibly even to arrange cardiac interventions, without having to cancel and reschedule the surgery.
A common modifiable issue is the need for coronary revascularization. None of the clinical guidelines recently published recommend a coronary bypass procedure to “get the patient through” an operation.2 Although post-bypass elective surgery is less risky, the additive risks of the bypass and the surgery outweigh the risk of going straight to surgery. When a coronary bypass is performed on a patient who did not otherwise need it, the patient's total risk becomes even greater. Instead, it is suggested that the patient have a coronary evaluation geared to his or her need for a coronary procedure as if there were no upcoming operation. Obviously, an operation is still upcoming, and if the patient needs a bypass at all, maybe he or she should have it before the other operation.
When angioplasty is concerned, the answer is not as clear. Because we have no definitive literature to guide us, the recommendation stays the same: do it if the patient needs it and time it according to the relative urgency of each condition. When should the practitioner go down the revascularization route? The practitioner should address revascularization when there is evidence of unstable coronary disease on the history, physical examination and electrocardiogram. Patients with vascular disease and claudication may have silent but significant coronary disease, and these patients may also need noninvasive imaging, perhaps using persantine thallium.
Severe aortic stenosis is another major modifiable cardiac risk factor. Although it is uncommon, it is critical to detect because it carries a high risk. A physician who hears a systolic murmur should feel and listen to the right carotid artery: if the pulse is strong and there is no radiation of the murmur, the patient is very unlikely to have severe aortic stenosis.3 If these criteria are not met, an echocardiogram will help assess the problem.
Upcoming elective surgery therefore represents an opportunity to carefully evaluate whether the patient needs a procedural intervention, and it is also an opportunity to address medical therapy. There is reasonably good evidence to show that among patients with no contraindications, beta blockers such as atenolol show a cardioprotective effect in the perioperative period.4 Many patients with indications for therapy with beta blockers (hypertension, postmyocardial infarction, angina) may not be receiving these agents. This situation can be considered in the pre-operative evaluation.
Other medications also should be evaluated preoperatively: aspirin therapy should be discontinued at least one week before surgery. Anticoagulants should be discontinued before surgery or switched to heparin at the time of surgery. Diabetic medication should be modified, bronchodilator therapy should be optimized and steroids might be given at stress dosages. In the elderly, sedatives should be critically evaluated: if they are to be discontinued, they should be tapered to prevent withdrawal reactions. Smoking cessation, an effective preoperative intervention, also presents the patient with an opportunity to quit smoking for good.
The same factors used to determine risk would have other, nonoperative implications. Functional status, which we ask about to establish exertional symptoms (such as angina), also has an impact on how the primary caregiver will address home care postoperatively and in the long term. King1 recommends performing a preoperative blood glucose test—it is a good time to screen for diabetes.
The family physician plays a critical role in preoperative evaluation by addressing multi-system risk factors, as well as by placing the operation in the larger context of the patient's overall health. The preoperative evaluation represents an opportunity not only to modify operative risk but also to address long-term health issues arising from the preoperative inquiry.
Dr. Palda is assistant professor in general internal medicine at the University of Toronto Faculty of Medicine, Toronto, Ontario.
Address correspondence to Valerie Palda, M.D., M.SC., 30 Bond St., Room 4-154 Victoria Wing, University of Toronto, Toronto, Ontario M5B 1W8.
1. King MS. Preoperative evaluation. Am Fam Physician. 2000;62:387–96.
2. Guidelines for assessing and managing the perioperative risk from coronary artery disease associated with major noncardiac surgery. American College of Physicians. Ann Intern Med. 1997;127:309–12.
3. Etchells E, Bell C, Robb K. Does this patient have an abnormal systolic murmur? JAMA. 1997;277:564–71.
4. Cohen AT. Prevention of perioperative myocardial ischaemia anad its complications. Lancet. 1998;351:385–6.
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