During laser microsurgery of the larynx, a rubber endotracheal tube wrapped with aluminum-foil tape starts to smolder and give off smoke. The first step is to
(A) suction the endotracheal tube
(B) add helium to the inspired gas mixture
(C) remove the endotracheal tube
(D) turn off the fresh gas flow
(E) pack a saline-soaked gauze sponge into the hypopharynx
C
When treating reflex sympathetic dystrophy of an arm, which of the following is the best indicator of a successful sympathetic blockade?
(A) A pinprick sensory deficit in the distribution of C6
(B) A 5°C increase in the temperature of the skin of the hand
(C) An accentuated psychogalvanometric response in the forearm
(D) An ipsilateral positive Horner's syndrome
(E) Decreased temperature sensation in the hand
B
A healthy, spontaneously breathing, supine, anesthetized patient has a PaCO2 to PetCO2 difference of 3 mmHg. Following institution of mechanical ventilation the value increases to 12 mmHg. The most likely cause of this change is
(A) cephalad displacement of the diaphragm
(B) decreased production of carbon dioxide
(C) increased cardiac output
(D) increased shunting of blood through dependent lung zones
(E) increased ventilation of nondependent lung zones
One day after a vaginal hysterectomy under epidural anesthesia, a patient has numbness and inability to dorsiflex the right foot. Her legs were placed in leg holders during the operation. The most likely cause is
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
In a patient with peripheral vascular disease, the most likely result of lumbar sympathetic block is
(A) increased blood flow to skin and decreased blood flow to muscle
(B) increased blood flow to skin and unchanged blood flow to muscle
(C) increased blood flow to skin and muscle
(D) decreased blood flow to skin and muscle
(E) decreased blood flow to skin and unchanged blood flow to muscle