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
When evaluating a screening test, which of the following is the most appropriate term for the proportion of patients with a disease who have a positive test result?
During axillary block of the brachial plexus, which nerve is most likely to be encountered if the needle is inserted through the posterior wall of the artery?
A 39-year-old patient with insulin-dependent diabetes mellitus receives thiopental 250 mg and succinylcholine 80 mg and is ventilated with 0.75% isoflurane in oxygen. Arterial pressure decreases abruptly from 140/100 to 80/50 mmHg while heart rate remains unchanged at 70 bpm. Failure of heart rate to increase most likely results from
(A) acute hypoglycemia
(B) autonomic neuropathy
(C) depression of sinus node function by thiopental
(D) depression of the baroreflex response by isoflurane
Anesthesia is induced with halothane in a 3-year-old girl. Sixty seconds after administration of succinylcholine 1 mg/kg intravenously, heart rate decreases rapidly from 120 to 60 bpm. The most likely cause is
(A) acute hyperkalemia
(B) failure to pretreat with a nondepolarizing relaxant
In a patient undergoing liver transplantation, sodium bicarbonate and calcium chloride are administered immediately before reperfusion of the transplanted liver to counteract
A pulmonary artery catheter is placed in an awake patient breathing room air. Typical right ventricular and pulmonary artery pressure tracings are obtained. With the catheter balloon inflated, blood drawn from the distal port has a PaO2 of 100 mmHg, while a simultaneous radial artery sample has a PaO2 of 90 mmHg. These data indicate that the