A 70-kg 24-year-old man with bilateral pneumonia whose lungs are being mechanically ventilated has the following measured parameters: tidal volume 750 ml; FiO2 0.7; rate 12/min; positive end-expiratory pressure 10 cmH2O; PaO2 75 mmHg; PaCO2 55 mmHg; pH 7.30. Which of the following alterations should be made in the ventilatory settings?
A woman at 39 weeks' gestation has been in labor for 12 hours. She has had nausea and vomiting for the past eight hours. Maternal arterial blood gas values are PaO1 85 mmHg, PaCO2 31 mmHg, and pH 7.50. Which of the following is the most likely cause of fetal distress occurring at this time?
(A) Hypocarbia-induced placental ischemia
(B) Impaired fetal oxyhemoglobin dissociation
(C) Shift to the left of the maternal oxyhemoglobin dissociation curve
Neuromuscular blockade of the diaphragm is best ensured by monitoring which of the following peripheral muscles?
(A) Adductor pollicis muscle
(B) First dorsal interosseous muscle
(C) Flexor hallucis muscle
(D) Muscles of the hypothenar eminence
(E) Orbicularis oculi muscle
E
After inserting a left-sided double-lumen endotracheal tube, both cuffs are inflated. When the right (tracheal) lumen is clamped, breath sounds are heard only in the lower right lung field. When the left (bronchial) lumen is clamped, breath sounds are heard over the entire left lung field. Where is the tube positioned?
(A) Tracheal orifice above the carina and bronchial limb in the right bronchus
(B) Tracheal orifice above the carina and bronchial limb in the left bronchus
(C) Tracheal orifice and bronchial limb both above the carina
(D) Tracheal cuff and bronchial limb both in the right bronchus
(E) Tracheal orifice and bronchial limb both in the left bronchus
A
Which of the following statements concerning the volume of distribution of a drug is true?
(A) It is equal to the sum of the volumes of the tissue spaces into which it diffuses
(B) It is equal to the volume to which it is distributed outside the plasma volume
(C) It is unaltered by the amount bound to red blood cells and plasma proteins
(D) It depends on elimination from plasma
(E) It relates the total amount of the drug in the body to the plasma concentration
A 20-year-old patient undergoes a thoracic vertebral stabilization procedure six hours after sustaining an acute transection of the spinal cord at T4. The risks of general anesthesia are greater in this patient than in a patient with an intact spinal cord because of
(A) autonomic hyperreflexia
(B) increased sensitivity to vasoconstrictor agents
(C) increased venous capacitance
(D) interruption of cardiac sympathetic reflexes
(E) hyperkalemia induced by succinylcholine
C
Which of the following is the most likely effect of intramuscular ketamine used for induction of anesthesia in a 2-year-old child undergoing elective surgery?