The plasma concentration of an intravenously administered drug follows the two-compartment kinetic model shown in the graph. Which of the following events is illustrated by the decline in plasma concentration shown at Time #2?
(A) Decreasing activity of the drug at its receptor site
(B) Distribution from plasma to tissue
(C) Elimination of the drug from plasma
(D) Increasing volume of distribution
(E) Redistribution from vessel-rich groups to vessel-poor groups
C
A sensory level of T2 is achieved after administration of spinal anesthesia. Which of the following lung volumes is LEAST likely to be affected?
A 70-kg, 77-year-old man Is undergoing left nephrectomy with nitrous oxide, oxygen, fentanyl, and midazolam anesthesia. He has a 90 pack-year history of cigarette smoking and has chronic obstructive pulmonary disease. One hour after incision, expiratory wheezing occurs and peak Inspiratory pressure increases from 35 to 65 cmH20; end-tidal PCO2 is unchanged, but SpO2 decreases from 97% to 88%. The most likely cause is