NMS. Casos Clínicos

19

Chapter 1 ♦ Preoperative Care

Case Variation 1.6.14. The patient has a loud right carotid bruit. ◆ ◆ A carotid duplex study should be performed to evaluate for carotid artery disease. Studies have found that one third of patients with carotid bruits have severe internal carotid steno- sis. For patients with a high-grade stenosis (80%–99%), carotid endarterectomy might be considered prior to lower extremity revascularization. The risk of neurologic events associated with noncardiac vascular surgery is low (i.e., about 0.4%–0.9%). ◆ ◆ The primary cause of morbidity and mortality remains myocardial ischemia and infarction. Case Variation 1.6.15. The patient had a stroke 2 years ago. ◆ ◆ A carotid duplex study should be performed in patients who have had a previous stroke with good neurologic recovery to assess the carotid arteries. In stroke patients with signifi- cant residual neurologic deficit, no further evaluation is necessary. ◆ ◆ Carotid endarterectomy is likely to be beneficial for stroke patients with good recovery of function and 70%–99% stenosis of the carotid artery cor- responding to the side of the stroke. Case Variation 1.6.16. The ankle-brachial index (ABI) is 0.2, and he has a grossly infected large toe. ◆ ◆ An infected extremity puts patients at higher risk for gangrene and subsequent amputation because the peripheral circulation does not allow the limb to heal. This particular patient should still have a workup for coronary artery disease, but his need for peripheral revas- cularization is more urgent than in an individual with rest pain and an ABI of 0.4. Thus, it may be necessary to proceed with revascularization despite an incomplete workup of his cardiac disease. If so, the man should be treated as if he were at risk for myocardial ischemia and his anesthesia managed accordingly. Case 1.7 Surgery in a Patient with Liver Failure A 47-year-old woman with a large umbilical hernia, which has been progressively increasing in size, would like to have it repaired. Her history is significant for chronic liver failure secondary to alcohol abuse; she states that currently she is not using alcohol. She is taking a diuretic for control of the ascites. On physical examination, moderate ascites and a 5-cm umbilical hernia are evident. In your assessment, you believe She has alcoholic cirrhosis. A: The major factors that influence the operative risk relate to the state of compensation and the severity of cirrhosis (Table 1-7). Well-compensated patients can tolerate most surgi- cal procedures, but poorly compensated patients cannot tolerate even mild sedatives. The severity of cirrhosis can be estimated by physical examination and laboratory studies using the Child-Turcotte-Pugh score (Table 1-8) or Model for End-Stage Liver Disease (MELD) score calculated using serum creatinine, bilirubin (mg/dL), and international normalized ratio (INR) (Table 1-9). SAMPLE Q: What factors affect the patient’s operative risk, and how are they evaluated?