An 86-kg, 67-year-old man is undergoing a second coronary artery bypass operation. Five minutes after administration of protamine, blood pressure is 69/40 mmHg, pulmonary artery pressure is 65/42 mmHg, and the cardiac output measured by thermodilution is 2.3 L/min. Which of the following is the most likely cause of these findings?
(A) Allergy to fish
(B) Increased plasma thromboxane concentration
(C) Increased plasma histamine concentration
(D) Insulin-dependent diabetes mellitus
(E) IgE antibodies to protamine
B
A patient receives remifentanil 25 mcg just before retrobulbar block with 0.25% bupivacaine 4 mL. Over the next 10 minutes, he develops apnea and loses consciousness. Which of the following is the most likely explanation?
(A) Effects of remifentanil
(B) Injection of local anesthetic into cerebrospinal fluid
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
C
In normal tissue, which property of drugs has the greatest effect on the speed of onset of a local anesthetic?
A 30-year-old man is brought to the emergency department after being rescued from a house fire. With the trachea intubated and FiO2 at 1.0, arterial blood gas values are PaO2 495 mmHg, PaCO2 28 mmHg, and pH 7.28. Hemoglobin saturation measured by co-oximeter is 50%. The most appropriate next step is to