A 23-year old 86 kg 65 inch woman is to have an anterior communicating aneurysm clipped. She had severe headache and lapse of consciousness eight days ago, but now is awake and oriented normally. She was told of difficulty with tracheal intubation for previous laparoscopy. Blood pressure is 150/85 mm Hg, pulse is 92, respirations are 15 and hemoglobin is 12.5.
I. Mental status
1. Explain the occurrence of headache and unconsciousness followed by recovery.
2. Is intracranial pressure likely to be elevated?
3. How would you determine if intracranial pressure was elevated?
4. Is a CAT scan helpful in determining this?
5. Is intracranial pressure related to volume of hemorrhage?
6. Which induction agents increase intracranial pressure?
Ketamine, which also increases cerebral blood flow and metabolism.
7. Which induction agents decrease intracranial pressure?
Etomidate, thiopental, propofol, and fentanyl decrease intracranial pressure secondary to a decrease in cerebral blood flow and metabolic rate.
6. Would you avoid sedative premedication?
7. How would you calm her anxiety?
II. Airway assessment
1. Routine exam reveals small mouth, full dentition, and a 3cm hyoid-mental distance. Do you need additional information?
2. What specific radiographs or measurements would you like?
3. What do you tell her about your airway management plans?
4. Is an "awake look" useful here?
5. Is the blind nasal approach acceptable?
6. What are the risks?
7. Would you order a fibreoptic bronchoscope?
8. Would you have an Ear, Nose and Throat surgeon available for tracheostomy?
1. Would you place an arterial line in this patient? Explain.
2. Would you insert it before or after induction?
3. Is pulse oximetry sufficient during intubation attempts?
4. Is hypercarbia dangerous in this patient?
5. How would you detect it?
6. Is a central venous catheter necessary? Explain.
1. Assume that fibreoptic bronchoscopy is used for endotracheal tube insertion. Should the patient be awake or asleep for its placement?
2. How would you prevent coughing?
3. How would you prevent hypertension?
4. Is thiopental indicated for brain protection?
5. What dose would you use?
6. Is electroencephalogram monitoring indicated?
7. Would you use a volatile anesthetic for maintenance?
8. Which volatile agent would you use for maintenance?
III. Deliberate hypotension
1. It is requested by the surgeon. What available methods are there?
2. Which one would you choose? Explain.
3. What is the lowest safe blood pressure?
4. Is it the same in all patients?
5. What factors aid in deciding what the lowest acceptable pressure is?
6. How would you monitor this patient?
7. What are the effects of nitroprusside on intracranial pressure? Describe mechanisms.
IV. Supraventricular tachycardia
1. A heart rate of 130-145 bpm is suddenly noted during emergence. What are the risks?
2. What is your differential diagnosis?
3. What is your treatment?
4. Would your management change if there were expiratory wheezes audible bilaterally?
I. Persistent somnolence
1. One hour after the patient arrives in the recovery room, she is still not responding to commands. The surgeon requests an analeptic. Do you agree?
2. What are the risks and benefits of analeptic therapy?
3. What are the risks and benefits of delaying neurologic exams?
1. What are the causes?
2. What are the untoward consequences?
3. What are the effects on oxygen consumption and CO2 production?
4. Would you paralyze the patient?