A normal adult is receiving general anesthesia via a standard circle system and controlled ventilation. Mass spectrometer data are shown. Which event is most compatible with these data?
One hour after induction of anesthesia for a posterior fossa craniotomy using opioid, relaxant, and nitrous oxide, the brain begins to protrude through the dura. The most effective measure to decrease intracranial pressure is to
A 68-year-old patient is undergoing total hip replacement during general anesthesia using positive pressure ventilation and neuromuscular blockade. Intraoperative monitoring shows a gradual decrease in end-tidal CO2, an increase in exhaled tidal volume, and an increase in measured FiO2. Which of the following is the most likely cause of these changes?
(A) Air entrainment around a deflated endotracheal tube cuff
(B) Channeling of the exhaled air through the carbon dioxide canister
(C) Fat embolism
(D) Inadequate muscle relaxation with spontaneous patient ventilation