A 58-year old 70 kg man is conscious but complains of headache forty-eight hours after documented subarachnoid hemorrhage while playing tennis. He is scheduled for clipping of an aneurysm in the supine position. He has a history of long-standing hypertension and had an uncomplicated myocardial infarction five months ago, with no post-infarction symptoms. He is on metoprolol. Electrocardiogram shows left bundle branch block. Blood pressure is 140/85 mmHg, pulse is 70 bpm, respirations are 19, temperature is 37.5 degrees centigrade, and hemoglobin is 11 gm/dl.
I. Assessment of neurologic condition
1. Does he have increased intracranial pressure?
2. Is this important to know preoperatively?
3. How would you assess him for increased intracranial pressure?
4. What is his neurological grade?
5. Is it important to know this?
II. Preoperative cardiac condition
1. Does the fact that this patient had a myocardial infarction five months ago increase his anesthetic risk? Explain.
2. What can you do to decrease his risk of reinfarction?
3. Compare metoprolol to propranolol.
1. Is morphine 10 mg plus phenergan 25 mg intramuscularly an appropriate premedication?
2. What is your rationale for premedication in patients with cerebral aneurysms?
3. Should mannitol be given preoperatively?
I. Choice of anesthesia
1. What are your concerns when planning induction of anesthesia for this patient?
2. What drugs would you use for induction?
3. Discuss the effects these drugs have on cerebral blood flow, cerebral metabolic rate of oxygen consumption, and transmural pressure?
4. Is nitrous oxide/fentanyl an appropriate combination for maintenance? Explain.
5. What is your choice for maintenance?
1. Is an arterial line required?
2. Suppose bilateral Allen's tests are abnormal.
3. Does end-tidal CO2 give the same information as paCO2? Explain.
4. Is a pulmonary artery catheter indicated?
5. Is a central line indicated?
III. Muscle relaxant
1. Are there special requirements for relaxation in this patient?
2. Is pancuronium the best drug of choice?
3. What is your choice?
4. Is a twitch monitor necessary? Why or why not?
IV. Management of induced hypotension
1. During dissection, the aneurysm tears and the surgeon requests immediate hypotension. How will you manage the patient?
V. Massive blood loss
1. Only six units of packed red cells are available, and all are used rapidly. What will you use while more blood is being cross-matched?
I. Early emergence
1. The surgeon requests that the patient be awakened in the operating room. What is your response?
2. After thiopental induction, isoflurane/fentanyl/nitrous oxide anesthesia, the patient does not awaken promptly. What is your response?
II. New postoperative neurologic deficit
1. Six hours postoperatively, the patient, who is now awake, develops paralysis of the contralateral arm and leg. There is no change in vital signs or level of consciousness. What is your differential diagnosis?
2. What is your management?