A 30-year-old, 70-kg woman with mitral stenosis is scheduled for elective laparoscopic sterilization. Preoperatively she is taking digoxin and an unknown medication for chronic mental depression. The EKG demonstrates atrial fibrillation. Heart rate is 68 bpm. Anesthesia is induced with thiopental followed by nitrous oxide 50%, halothane 0.75%, and a continuous succinylcholine infusion. The ventilator is set to deliver a minute volume of 5 liters through an endotracheal tube. As the carbon dioxide is being insufflated into the abdomen, the blood pressure is noted to be elevated (150/100 mmHg) and ventricular bigeminy is present. The most appropriate therapy is to
(A) increase the halothane concentration to 1.25%
(B) discontinue the succinylcholine infusion
(C) increase minute ventilation to 7.5 L/min
(D) administer potassium 5 mEq intravenously over one minute followed by propranolol 0.25 mg
(E) measure arterial blood gas and serum electrolyte values
A 35-year-old woman who takes a diuretic daily for chronic hypertension has a serum potassium concentration of 3.1 mEq/L on the morning of an elective hysterectomy. An EKG shows left ventricular hypertrophy. The most appropriate management is to
(A) consult with a cardiologist before proceeding
(B) initiate oral potassium replacement and proceed with the operation when potassium concentration is normal
(C) initiate intravenous potassium replacement and proceed with the operation
(D) initiate intravenous potassium replacement and proceed with the operation when potassium concentration is 4 mEq/L
(E) proceed with the operation without intervention
E
The carbon dioxide/ventilation response curve
(A) is primarily a measure of the integrity of the peripheral chemoreceptors
(B) shows parallel displacement to the left in the presence of opioids
(C) is linear between a PaCO2 of 20 and 120 mmHg
(D) shows progressive changes in slope with increased doses of halogenated anesthetics
(E) is unaffected by a decrease in PaO2 to 60 mmHg