A 72- year old 68 kg male with rectal carcinoma is scheduled for abdomino-perineal resection. He has a known history of alcoholic cirrhosis. Moderate ascites is noted on physical exam. The electrocardiogram shows an old anteroseptal myocardial infarction. Blood pressure is 100/70 mmHg, pulse is 68 bpm, temperature is 36 degrees centigrade, respirations are 16, bilirubin is 1.6 mg/dl, prothrombin time is 16 seconds, and hemoglobin is 10.5 gm/dl.
I. Liver function
1. Why does this patient have ascites?
2. What is the significance of cirrhosis to anesthetic care?
3. Interpret the bilirubin and prothrombin values.
4. What is the importance of these to your management?
5. Are liver function studies required? Explain.
II. Prior myocardial infarction
1. What is the significance of the old anteroseptal myocardial infarction to the anesthetic care?
2. The patient denies a clinical history of myocardial infarction. What additional information may be sought concerning the cardiac system?
3. What is the prognosis for reinfarction in the perioperative period?
III. Anemia and transfusion
1. Interpret the hemoglobin value.
A hemoglobin of 10 gm/dl indicates anemia, and is considered in light of chronic disease, his fluid status, the major surgery scheduled, the probability of extensive blood loss, and his myocardial and hepatic disease with associated increased likelihood of cardiac ischemia and coagulation abnormalities.
2. Should the patient be transfused preoperatively? Explain.
No. The patient has carcinomatous disease of a chronic nature, is asymptomatic, and has stable vital signs. However, the likelihood of his requiring intraoperative blood transfusion is great, and at least one large-bore intravenous line is necessary, with blood available intraoperatively.
3. Does evidence of prior myocardial infarction influence your choice? Explain.
1. Is central pressure monitoring indicated? Explain.
2. Would you use a central vein or a pulmonary artery catheter for central pressure monitoring? Explain your rationale.
3. What specific information is sought with lead V5 on the electrocardiogram?
4. Differentiate between ST segment depression and elevation.
5. What are additional means to detect myocardial ischemia intraoperatively?
II. Choice of anesthetic
1. A colleague suggests continuous epidural anesthesia. Do you agree? Explain.
2. The patient insists on general anesthetic. What is your choice of agents? Explain your rationale.
3. What are the effects of inhalation anesthetics on hepatic blood flow?
4. What are the effects of inhalation anesthetics on hepatic function?
5. What is the difference between halothane and isoflurane?
6. What is the mechanism responsible for this difference?
III. Muscle relaxants
1. Does liver disease influence your choice of muscle relaxant? Explain.
2. What is your choice of relaxant for general anesthetic? Give reasons.
IV. Fluid management
1. Should intravenous dextrose be given initially?
2. Discuss advantages and disadvantages.
3. Is this patient at risk for hypoglycemia? Explain.
4. Define third space loss.
5. What is the specific fluid therapy for third space loss in AP resection?
6. Is albumin indicated in this patient? Explain.
7. What are potential hazards of hypoalbuminemia preoperatively?
1. On a FIO2 of 50%, saturation by pulse oximeter is 95%. What is the significance of this?
2. What are causes of desaturation in this patient?
3. How will you respond?
I. Oliguria in the recovery room
1. The urine output is 10 ml/hr in the first two hours postoperatively. What is your differential diagnosis?
2. How will you assess this?
3. Are urine electrolytes helpful? Explain.
4. After the fluid challenges, no response occurs. What additional steps will you take?
1. What technique and drugs would you recommend for postoperative analgesia? Explain.
2. Contrast with other modalities.
3. What are the differences between epidural morphine and fentanyl?
III. Cardiac arrest in the recovery room
1. The patient has multifocal premature ventricular contractions one hour postextubation in the recovery room. What are potential causes?
2. What are treatment choices?
3. The patient develops ventricular fibrillation. What is your management?