Which of the following statements concerning carbon monoxide poisoning is true? A 38-year-old woman with a large goiter has undergone subtotal thyroidectomy. Airway obstruction is noted immediately after extubation despite normal vocal cord function on laryngoscopy. Which of the following is the most likely explanation?
A 60-kg, 70-year-old man requires open reduction and internal fixation of an intertrochanteric fracture sustained 24 hours ago. Serum creatinine concentration is 1 mg/dl and blood urea nitrogen concentration is 40 mg/dl. The most likely cause of these findings is
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
Which of the following best describes the relationship between cerebral perfusion pressure and cerebral blood flow in a patient with untreated chronic hypertension?
(A) It is constant at mean blood pressures between 50 and 150 mmHg
(B) It is linear for all blood pressures
(C) Flow versus pressure curve is hyperbolic
(D) Flow versus pressure curve is shifted to the right
(E) Flow versus pressure curve is shifted to the left
A patient is placed in the prone jackknife position for lumbar subarachnoid injection of tetracaine 10 mg in 10 ml of preservative-free sterile water. Which of the following results is most likely?