A 38-year-old woman with B-positive blood requires immediate blood transfusion during abdominal hysterectomy. No B-positive blood is available; O-negative blood is used. Three minutes after starting transfusion of packed red blood cells, the patient develops tachycardia, bronchospasm, and hypotension. Which of the following is the most likely cause?
(A) Anaphylactic reaction to donor IgA
(B) Bacterial contamination of transfused blood
(C) Hemolysis resulting from ABO incompatibility
(D) Hypocalcemia
(E) IgG-mediated reaction to Rh antigens
A
Which of the following statements concerning cerebral blood flow (CBF) during anesthesia is true?
(A) CBF changes minimally when PaC02 increases from 30 to 40 mmHg
(B) CBF changes minimally when P02 decreases from 160 to 100 mmHg
(C) CBF is autoregulated when mean arterial pressure is 40 mmHg
(D) CBF is coupled to cerebral metabolism during isoflurane anesthesia
(E) CBF is unaffected by 1.2% isoflurane at a PaC02 of 40 mmHg
B
A 55-year-old man undergoes abdominal perineal resection in the lithotomy position during combined epidural (bupivacaine 0.5%) and isoflurane anesthesia. The epidural catheter is left in place with an infusion of fentanyl 50 jug/hr. Twelve hours after surgery, the patient has left footdrop. Which of the following is the most likely explanation?
(A) Epidural hematoma
(B) Epidural opioid
(C) Inadequate padding of the knee during surgery
(D) Nerve injury from the epidural catheter
(E) Residual effects of the local anesthetic
C
Which of the following is the correct sequence of anatomic structures encountered when using a paramedian approach for lumbar spinal anesthesia?
(A) Ligamentum flavum — dura mater — arachnoid mater
(B) Interspinous ligament — ligamentum flavum — dura mater — arachnoid mater
(C) Posterior longitudinal ligament — ligamentum flavum — dura mater — arachnoid mater
(D) Anterior longitudinal ligament — ligamentum flavum — dura mater — arachnoid mater
(E) Ligamentum flavum — dura mater — pia mater — arachnoid mater
A 2.2-kg, 6-hour-old neonate is to undergo gastrostomy followed by repair of a tracheoesophageal fistula. During induction with halothane, air, and oxygen, the abdomen becomes distended. Appropriate management is to
(A) intubate and assist spontaneous ventilation
(B) intubate and control ventilation
(C) insert an orogastric tube
(D) allow the patient to breathe spontaneously by mask until gastrostomy
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
Nonsteroidal analgesics such as aspirin decrease pain by
(A) decreasing axonal transmission of pain stimuli through a local anesthetic mechanism
(B) directly competing with substance P for receptor occupancy
(C) inhibiting enzymatic breakdown of met-enkephalin
(D) inhibiting production of prostaglandin E2
(E) potentiating the action of endorphin in the substantia gelantinosa of the spinal cord