A mechanically ventilated newborn infant is undergoing gastroschisis repair during halothane anesthesia. Based on the right radial artery catheter tracing shown, which of the following is the most appropriate conclusion?
(A) The abdomen has not yet been incised
(B) The anesthetic should be changed from halothane to isoflurane
The figure describes the uptake of nitrous oxide 75% by individual tissue groups (VRG = vessel-rich group, MG = muscle group, FG = fat group) and their sum (total uptake, TU). Which set of labels accurately describes the curves?
A 62-year-old woman with obesity and type II diabetes mellitus is scheduled to undergo vitrectomy of the right eye. Five minutes after retrobulbar injection with 0.75% bupivacaine 4 ml and intravenous administration of fentanyl 50 ju-g and midazolam 1 mg, she is apneic and unresponsive. Which of the following is the most likely cause?
(A) Fentanyl-midazolam interaction
(B) Hypoglycemia
(C) Intravenous bupivacaine
(D) Retrobulbar hematoma
(E) Subarachnoid bupivacaine
C
Which of the following statements concerning relationships among alveolar pressure, volume, and surface tension is true?
(A) Surface tension of surfactant decreases as alveolar volume decreases
(B) Surface tensions of water and of surfactant behave similarly as volume decreases
(C) Changes in alveolar surface tension with volume are the same during expansion as during contraction
(D) Pressure in the alveolus is inversely related to surface tension
(E) Pressure in the alveolus is directly related to alveolar radius
A patient with lumbar disk disease requires lumbar epidural injection of a corticosteroid for control of low back pain. Which of the following statements concerning this treatment is true?
(A) Maximum effect occurs one hour after injection
(B) Maximum effect occurs when drug concentration peaks in cerebrospinal fluid
(C) Maximum effect occurs during the acute phase of the disease
(D) The beneficial effect results primarily from sympathetic neurolysis
(E) It is contraindicated if the patient has had prior surgical procedures on the lumbar disks