During isoflurane anesthesia, a 45-year-old patient with chronic asthma has wheezing, prolonged expiration, sinus tachycardia of 120 bpm, and premature ventricular contractions. Preoperative medication included cromolyn and theophylline (serum level 20 jag/ml). The most appropriate treatment is to administer
(A) albuterol aerosol
(B) aminophylline by intravenous infusion
(C) cromolyn aerosol
(D) halothane
(E) hydrocortisone by intravenous bolus
A
An otherwise healthy 16-year-old girl is undergoing posterior spinal fusion for thoracolumbar scoliosis. During the procedure, the most likely cause of a marked decrease in the amplitude of the somatosensory evoked potentials after stimulation of the posterior tibial nerve is
(A) administration of fentanyl 30 jag /kg for induction
(B) administration of isoflurane 1.3 MAC for maintenance
(C) administration of vecuronium 0.15 mg/kg
(D) a decrease in body temperature from 37 to 35°C
A 70-year-old man has a pacemaker set at VOO mode at 70 bpm with temporary atrial and ventricular wires placed prior to separation from cardiopulmonary bypass. Fifteen minutes after separation, he develops atrial fibrillation with a ventricular response of 80 to 100 bpm. Which of the following ECG findings is most likely?
(A) Irregular atrial and ventricular complexes with loss of pacer artifacts
(B) Irregular ventricular complexes with preserved ventricular pacer artifacts at 70 bpm
(C) Occasional pacer artifacts when intrinsic ventricular rate is slower than 70 bpm
(D) Regular ventricular complexes at 70 bpm
(E) Ventricular complexes with preserved atrial and ventricular pacer artifacts at 70 bpm
B
Six hours after coronary artery bypass grafting, a pulmonary artery catheter oximeter shows a mixed venous hemoglobin oxygen saturation of 50%. This value may result from each of the following EXCEPT
Which of the following combinations of hemoglobin, blood gases, and cardiac output provides the greatest delivery of oxygen to tissue? (Hb, PaO2, SaO2, CO)