During frontal craniotomy for removal of an astrocytoma, the surgeon notes that the brain is "tight." The patient is receiving nitrous oxide 50% in oxygen, isoflurane 0.5%, fentanyl, and pancuronium. Heart rate is 92 bpm, blood pressure is 110/60 mmHg, end-tidal carbon dioxide tension is 31 mmHg, and oxygen saturation is 98%. The most appropriate initial treatment is to
(A) administer a beta-adrenergic blocker
(B) administer thiopental
(C) decrease isoflurane concentration
(D) decrease mean arterial pressure to 60 mmHg
(E) increase alveolar ventilation
E
A 55-year-old man is undergoing craniotomy in the sitting position. Mean arterial pressure is 75 mmHg; arterial blood gas values are PaCO2 41 mmHg and pH 7.37. End-tidal CO2 is 7 mmHg. Which of the following is the most likely cause of the increased PaCO2 to PetCO2 gradient?
(A) Decreased cardiac output
(B) Endobronchial intubation
(C) Hyperinflation of the lungs
(D) Partial disconnect of the capnograph sample tubing
A 50-year-old man is scheduled to undergo emergency craniotomy for evacuation of an epidural hematoma. His Glasgow Coma Scale score is 6; heart rate is 54 bpm, and blood pressure is 190/110 mmHg. The most appropriate initial management is administration of which of the following agents?
A 14-month-old child has tetralogy of Fallot with dynamic obstruction to right ventricular outflow. Which of the following is most likely to decrease cyanosis in this child?
If minute ventilation remains constant, which of the following changes in PetCO2 and PaCO2 will result from a decrease in cardiac output? (PetCO2, PaCO2)