A waste-gas scavenger has an active disposal system. Which of the following safety features is necessary to prevent removal of excess gas from the breathing circuit?
An atrioventricular sequential demand pacemaker is placed in a patient who has abnormal atrioventricular conduction. Each of the following statements about this situation is true EXCEPT:
(A) Electrocautery could lead to long pauses in the paced rhythm
(B) Placing a magnet over the generator will convert it to an asynchronous (fixed rate) unit
(C) If complete heart block develops, the paced ventricular rate will be the same as the sinus node rate
(D) An atropine-induced increase in the sinus rate will increase the ventricular rate
(E) During symptomatic tachyarrhythmia, cardioversion would be contraindicated because it would alter the pacemaker's function
Following cardiopulmonary bypass, right ventricular distention is noted after infusion of protamine 40 mg. Pulmonary artery pressure has increased from 25/18 to 50/30 mmHg and systemic arterial pressure has decreased from 110/65 to 0 mmHg. Which of the following is the most appropriate treatment?
(A) Administration of amrinone
(B) Administration of nitroglycerin
(C) Administration of phenylephrine
(D) Initiation of intra-aortic balloon pump assist
(E) Reheparinization and resumption of cardiopulmonary bypass
During craniotomy in the sitting position, end-tidal carbon dioxide tension suddenly decreases. Ventilatory excursion of the chest is normal. Further evaluation is most likely to show a decrease in