A 33-year old woman with a 10-year history of multiple sclerosis is scheduled for bilateral tubal ligation. Medications include phenelzine, a MAO inhibitor, for depression, and intermittent steroids for exacerbations of the multiple sclerosis. Examination reveals dysarthria, right-sided intention tremor, and cerebellar ataxia. Blood pressure is 130/80 mmHg, pulse is 84, respirations are 14, and temperature is 36.8 degrees centigrade.
I. Multiple sclerosis
1. Does multiple sclerosis add to the risk of anesthesia? If so, how?
1. Would phenelzine use cause you to alter your anesthetic approach for this patient? Why or why not?
2. Should it be discontinued preoperatively? Explain.
3. Would you have the same concerns if she were taking a tricyclic antidepressant? Explain.
1. Should she receive corticosteroid preoperatively? Why or why not?
2. You give 50-mcg intravenous fentanyl, and she becomes apneic. You rapidly place a mask, and are unable to ventilate the patient. What is your diagnosis, treatment, and what can you do to prevent it?
Opioid-induced muscle rigidity is the diagnosis, and the treatment is positive pressure ventilation. If unable to ventilate, paralysis and rapid intubation are warranted. Premedication with 2-5 mg of midazolam one minute before induction may decrease this effect, and pre-treatment with small dose of non-depolarizing muscle relaxant may decrease rigidity and allow for assisted mask ventilation.
1. Would you monitor this patient differently than a healthy female for a tubal ligation? Explain.
2. What monitors would you use for this patient that would be different?
II. Choice of anesthesia
1. Would an epidural be appropriate? Why or why not?
2. Would general anesthesia be a better choice?
3. If regional anesthesia were selected, would you insert a catheter?
4. Would you use epinephrine in the test dose? Why or why not?
5. What local anesthetic would you choose, and why?
6. Would you use epidural anesthetic for postoperative pain relief?
7. If general anesthesia is used, is a rapid sequence induction indicated? Why or why not?
8. What would be your induction drugs of choice?
9. Which muscle relaxant would you choose, and why?
10. Is it safe to use succinylcholine in this patient? Explain.
11. Would a vapor anesthetic be preferable to nitrous/narcotic for maintenance? Why or why not?
III. Air embolism:
1. During preparation for laparoscopy, the surgeon asks if you prefer CO2 or nitrous oxide for insufflation. Your answer?
3. During laparoscopy, the patient suddenly becomes hypotensive with ventricular bigeminy, decreased oxygen saturation, and neck vein distension. What is your differential diagnosis?
4. What is your treatment?
IV. Acute hemorrhage
1. During tubal ligation, the surgeon encounters significant hemorrhage and plans exploratory laparotomy. Discuss your sequential approach.
2. No blood has been prepared, and estimated blood loss over the first ten minutes is about 1250 ml. How will you proceed?
I. Respiratory distress
1. In the recovery room, the patient is tachypneic to 40 breaths/min, and is gasping. What is your differential diagnosis?
2. What is your treatment?
1. The recovery room nurse reports a temperature of 39 degrees centigrade two hours postoperatively. Would you treat this? Why or why not?
2. How would you treat this?
III. Pain management
1. The patient complains of severe shoulder pain. Why?
2. How will you manage the pain?
3. The recovery room nurse suggests patient-controlled analgesia. Do you agree? Explain.