Which of the following is a characteristic of VVI pacemakers?
(A) They are inhibited by the R wave
(B) They are triggered by the P wave
(C) They are more likely to precipitate ventricular fibrillation than fixed-rate pacemakers
(D) They are unaffected by unipolar electrocautery
(E) They sense both atrial and ventricular depolarization
A
A previously healthy, 60-kg, 17-year-old boy is undergoing emergency surgery for a gunshot wound involving the iliac vein. Ventilation is controlled with a tidal volume of 700 ml/breath, rate of 10/min, and peak inspiratory pressure of 30 cmH2O. Body temperature is normal. The most likely cause of an end-tidal carbon dioxide partial pressure of 16 mmHg is
Which of the following antihypertensive drugs is most likely to cause bradycardia?
(A) Captopril
(B) Clonidine
(C) Hydralazine
(D) Nifedipine
(E) Phenoxybenzamine
B
In the PACU after resection of an occipital astrocytoma, a patient has a urine output greater than 300 ml/hr, serum osmolality of 310 mOsm/L, and a hematocrit of 40% (equal to the preoperative value). Intraoperative blood loss was estimated to be 750 ml; furosemide and mannitol were administered during the procedure. The most appropriate next step is
(A) restriction of free water
(B) administration of 0.9% saline solution
(C) administration of desmopressin
(D) administration of dexamethasone
(E) CT scan of the brain
B
Each of the following would slow induction with a volatile anesthetic agent EXCEPT
(A) hypoalbuminemia
(B) hyperlipemia
(C) clean rubber tubing in the circle system
(D) fresh soda lime
(E) obesity
A
Following blunt trauma to the chest, a patient has tachycardia, hypotension, and markedly distended neck veins. Each of the following is expected EXCEPT
(A) cardiac output of 2.1 L/min
(B) mixed venous oxygen saturation of 75%
(C) pulmonary artery occlusion pressure of 25 mmHg
(D) pulmonary artery diastolic pressure of 25 mmHg
Diffuse microvascular bleeding is noted in a patient who has received 25 units of whole blood for a liver resection. Platelet count is 40,000/mm3, prothrombin time is 18 sec, activated partial thromboplastin time is 54 sec, and serum fibrinogen concentration is 60 mg/dl. The most likely cause of the bleeding is
A 55-year-old man has quadriplegia after undergoing suboccipital craniotomy in the sitting position for treatment of acoustic neuroma. Which of the following is the most likely cause?
(A) Air embolism with the presence of a probe-patent foramen ovale
(B) Compression of the cervical cord related to neck flexion
(C) Jugular venous obstruction
(D) Postoperative tension pneumocephalus
(E) Sustained elevation of cerebral perfusion pressure