A 38-year old 5'6" diabetic woman weighing 120 kg presents for excision and skin grafting of an ulcer on the right ankle. She takes NPH insulin 30U/day. Physical examination reveals distant breath and heart sounds, full dentition with normal mouth opening, and a short neck with redundant soft tissue. Electrocardiogram shows normal sinus rhythm with borderline right ventricular hypertrophy. Blood pressure is 130/90 mmHg, pulse is 88 bpm, hemoglobin is 12 gm/dl, glucose is 190 mg/mL, and paO2 is 78 mmHg on room air.
1. Is her diabetes adequately controlled for surgery?
2. What additional information would you want to arrive at this decision?
3. Why is this important?
II. Pulmonary status
1. What are your concerns about her pulmonary status?
2. Does the borderline ventricular hypertrophy concern you? Why or why not?
3. Are additional studies required to assess her cardiopulmonary status?
4. Which tests would you order? Explain your rationale.
I. Anesthetic choice
1. Do you recommend regional or general anesthesia? Explain your rationale.
2. Does her diabetes influence your decision? Explain.
3. Does her obesity influence your decision? Explain.
1. Would you monitor this patient differently than you would for a slender diabetic for the same procedure? Why?
2. Does the presence of right ventricular hypertrophy alter your monitoring? Why or why not?
3. How does it alter your monitoring?
4. A colleague recommends a pulmonary artery catheter with continuous oxygen saturation monitoring. Do you agree?
5. How will you monitor her diabetic status with regional anesthesia?
6. How will you monitor her diabetic status with general anesthesia?
III. Anesthetic induction and intubation
1. The patient refuses regional. Will you do a rapid sequence induction? Explain.
2. What are the hazards of rapid sequence induction in this patient?
3. Would premedication with ranitidine and metoclopramide influence your decision?
4. Would awake blind nasal or fiberoptic intubation be preferable? Explain.
5. When is it mandatory to premedicate to attenuate sympathetic nervous system responses?
Premedication is mandatory to blunt sympathetic nervous system responses in patients with known hypertension or coronary artery disease, scheduled for intubation.
6. What drugs may be used to attenuate sympathetic nervous system responses to laryngoscopy and intubation?
Drugs used to decrease the sympathetic nervous system response to intubation include short-acting beta-blockers, clonidine, and high-dose opioids.
5. What drugs will you use for maintenance of anesthesia? Explain your rationale.
1. Oxygen saturation gradually declines from 99% to 93% thirty minutes after induction. Faint wheezing is heard with a precordial stethoscope. What is your differential diagnosis?
2. How will you confirm your diagnosis?
3. How will you treat?
1. Would you recommend early or delayed extubation for this patient? Explain.
2. What would be your criteria for extubation?
3. Are these criteria altered by her cardiopulmonary status? Explain.
II. Pain management
1. The patient has extreme fear of postoperative pain. How will you manage her pain?
2. Would epidural narcotics be preferable to intravenous ones? Why or why not?
3. How do intravenous induction agents work?
They increase transmission of the inhibitory neurotransmitter gamma aminobutyric acid, interfering with transmembrane electrical activity.
4. What are some properties of an ideal induction agent?
It should be water soluble, compatible with intravenous fluid, have a rapid onset of anesthesia without untoward cardiovascular, pulmonary, or neurologic side effects, have anticonvulsant, antiemetic, analgesic, and amnestic properties, have a rapid recovery time, and there should be no renal or hepatic dysfunction or teratogenicity.
3. The patient refuses to have a needle placed in her back while she is awake, but says you can do an epidural while she is anesthesized. Will you do it?