ORAL EXAMINATION: Wednesday, May 9, 2007

Examiners please note: This is a type B examination. Preoperative topics ARE discussed. Please leave 5 minutes at the conclusion for feedback.

A 40-year-old, 50 Kg, 5'2" tall woman is scheduled for an abdominal hysterectomy for menorrhagia. She has a history of myasthenia gravis and a hiatal hernia with esophageal reflux. Her medications include pyridostigmine (Mestinon) 360 mg/day, prednisone 15 mg/day and antacids. Vital signs are P 50, BP 120/50, R 15, T 37°C. Her Hgb is 9.3 gms/dl.

A. PRE-OPERATIVE EVALUATION -10 Minutes

1. Myasthenia Gravis: What are the anesthetic concerns with myasthenia gravis? How would you assess the adequacy of therapy? How would you manage medications pre-operatively? Should she have PFTs pre-op? If so, which? Why? What do you expect if therapy adequate.

2. Hiatal Hernia: Of what importance is the history of hiatal hernia with reflux? Does the severity of reflux affect the risk of aspiration? How would you determine the severity of reflux? What can/should you do pre-operatively to decrease the risk of reflux and aspiration? Does the history of hiatal hernia with reflux mandate a rapid sequence anesthetic induction and tracheal intubation? Why? Does the hx of myasthenia gravis change your choice of drugs for a rapid sequence induction? How and why?

3. Steroid Therapy: Does chronic steroid therapy affect anesthetic management? How? Is usual daily dose of IS mg prednisone sufficient for intra-operative purposes? Why/why not? How do you recognize adrenal insufficiency during general anesthesia? Are there risks in administering high dose hydrocortisone (l00 mg) preop? Discuss.

B. INTRA-OPERATIVE MANAGEMENT - 10 Minutes

1. Selection of Monitors: Is train-of-four monitoring reliable in myasthenia? Would it indicate the need/non-need for a muscle relaxant for this operation? Does her anemia influence your ability to perform Sp02 monitoring by oximeter? Discuss. Would you monitor ETC02? Why? Is there benefit to assessing waveform or is ETC02 value alone sufficient? Explain.

2. Anesthetic Technique: Would regional anesthesia be an acceptable technique for this patient? Why/why not? Discuss advantages/disadvantages. If patient consented to regional technique, would you suggest spinal or epidural approach? Explain choice.

3. Anesthetic maintenance: The patient prefers to be asleep. You respond? Explain. How would you induce general anesthesia? Rationale for choice. Would you avoid succinylcholine for intubation? Why/why not? If surgeon can perform hysterectomy in 50 minutes, would a succinylcholine infusion be preferable to other relaxants? Why/why not? Could you provide satisfactory anesthesia without a relaxant? Explain. Would you favor a potent inhalation anesthetic or opioid technique? Defend choice.

4. Bleeding: During pelvic dissection, the patient begins to bleed excessively. How will you determine when to transfuse? After administration of 2 units packed cells, the patient continues to bleed. Blood pressure is 90/40 and pulse is 105. There is no blood available. What will you do? Is FFP indicated? Why/why not? You note her urine is becoming red. Why might this be happening? How will you evaluate? Manage? Why?

5. Extubation: How will you evaluate suitability for extubation in this patient? If you used a non-depolarizing relaxant, would you reverse? If so, how? Why?

C. ADDITIONAL TOPICS - 5 Minutes

1. Management of a burned patient: You are called to the ER for consultation about a patient with burns to the arms, chest and face. What are your specific concerns? How do you decide whether or not tracheal intubation is required? Discuss airway management. How do you plan fluid therapy? Endpoints?

2. Regional anesthesia and COPD: A 50-year-old man with COPD and a productive cough is scheduled for emergency exploration for probable testicular torsion. PFT's 3 months ago showed FVC 3.0 L, FEV1 1.0 L, no improvement with bronchodilators, and room air Pa02 65, PaC02 4S, pH 7.40. How interpret? Repeat? Why/why not? Patient asks if regional anesthesia would be safest for him. You respond? Assume he prefers regional, how would you proceed? Ten minutes after spinal injection patient complains of difficulty breathing. Ddx? Rx? Assume sensory level is T4. Does this contribute? Why/why not? Management? Explain.