Preoperative administration of alpha-adrenergic inhibitors will usually reverse ECG changes due to
(A) catecholamine myocarditis
(B) Preoperative administration of alpha-adrenergic inhibitors decreases operative mortality
(C) Beta-adrenergic inhibitors should be administered preoperatively only in conjunction with alpha-adrenergic
inhibitors
(D) Vasopressor therapy may be necessary postoperatively for treatment of hypotension
E
Syringe A contains 100 ml of normal blood with a PO2 of 2 mmHg, and syringe B contains 100 ml of normal blood with a PO2 of 98 mmHg. The contents of the two syringes are mixed anaerobicaily to equilibrium. The PO2 of the resultant mixture Is
A 25-year-old man with Wolff-Parkinson-White syndrome has paroxysmal supraventricular tachycardia with a heart rate of 200 bpm during insertion of an intramedullary rod for a femoral fracture. Duration of the QRS complex is 0.12 sec. Each of the following antidysrhythmic agents would be appropriate for use in this patient EXCEPT
(A) lidocaine
(B) metoprolol
(C) procainamide
(D) propranolol
(E) verapamil
E
Which of the following is an effect of magnesium sulfate at the neuromuscular junction?
(A) Augmentation of acetylcholine reuptake
(B) Decrease in acetylcholine binding
(C) Decrease in acetylcholine metabolism
(D) Decrease in the prejunctional release of acetylcholine
(E) Potentiation of the effects of ionized calcium
A patient has seizure activity 30 seconds after injection of 0.25% bupivacaine 2 ml with epinephrine 1:200,000 for stellate ganglion block. The most likely cause is
(A) reaction to epinephrine in the anesthetic solution
The primary mechanism for respiratory arrest following a spinal anesthetic to T2 is
(A) block of carotid chemoreceptors
(B) direct effect of local anesthetic on the medulla
(C) ischemia of respiratory centers in the medulla
(D) paralysis of the diaphragm by neural block
(E) paralysis of intercostal muscles
C
A patient undergoes axillary block for placement of an arteriovenous shunt in the forearm. Blockade of the musculocutaneous nerve is not achieved. Injection of a local anesthetic at which of the following sites will provide the required sensory block?
(A) Between the tendon of the palmaris longus and flexor carpi radialis
(B) Body of coracpbrachialis muscle
(C) Medial to the brachial artery at the elbow
(D) Proximal to the medial epicondyle against the medial surface of the humerus
(E) Superficial to the pulse of the axillary artery
Fetal distress is noted after administration of an epidural local anesthetic during labor. Fetal scalp pH is 7.0. Compared with a fetus with a scalp pH of 7.3, in this fetus the local anesthetic is present in
(A) a higher concentration, with a larger fraction in the ionized form
(B) a higher concentration, with a larger fraction in the unionized form
(C) the same concentration, with a larger fraction in the ionized form
(D) the same concentration, with a larger fraction in the unionized form
(E) a lower concentration, with a larger fraction in the ionized form