Statistical analysis of 20 patients shows a mean cardiac output (CO) of 5 L/min with a standard deviation of 1 L/min. The distribution pattern in the sample population is normal. Which of the following is the most appropriate conclusion?
(A) Approximately 33% of the sample population would be expected to have a CO between 4 and 6 L/min
(B) Approximately 95% of the sample population would be expected to have a CO between 3 and 7 L/min
(C) Ten of the sample patients have a cardiac output greater than 5 L/min
(D) The mean and the median are both at the 50th percentile
(E) The median and the mode are the same in the sample population
A 5-year-old boy is to undergo microlaryngeal carbon dioxide laser vaporization of laryngotracheal papillomas under halothane administered through a small polyvinylchloride (PVC) endotracheal tube. The diluent gas mixture LEAST likely to support laser combustion of the PVC tube is
A 62-year-old man, who had a myocardial infarction three years ago, complicated by congestive heart failure and renal failure, is undergoing a colectomy. A pulmonary artery catheter demonstrates a cardiac output higher than measurements recorded during a cardiac catheterization two months after the infarction. Which of the following most likely contributes to the increased cardiac output?
(A) Creation of an arteriovenous fistula
(B) Increased hemoglobin concentration from 10 to 12 g/dl
(C) Stimulation of carotid body receptors
(D) Transcutaneous nitroglycerin
(E) Use of a beta-adrenergic blocker to prevent myocardial reinfarction
Which of the following differentiates midazolam from diazepam administered intravenously in equipotent doses?
(A) Greater hemodynamic stability
(B) Lack of active metabolites
(C) Less respiratory depression
(D) Longer duration of action
(E) More rapid onset
B
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
Volume-cycled flow generators are preferred over pressure-cycled ventilators in critical care units because they
(A) have a lower compression volume
(B) limit peak airway pressure
(C) maintain constant ventilatory volume with changes in lung compliance
(D) more readily compensate for gas leaks
(E) permit more accurate measurement of the patient's minute volume
C
Following axillary block for insertion of an arteriovenous fistula in the forearm, a patient has pain on surgical incision. Which of the following nerves should be blocked to relieve this pain?
A healthy, 18-year-old, 65-kg woman undergoing diagnostic laparoscopy is being monitored with a properly functioning and calibrated capnograph. The end-tidal carbon dioxide concentration is 6%, and the inspired carbon dioxide concentration is 1%. This may be caused by each of the following EXCEPT
(A) malfunction of the expiratory valve in a circle system
(B) low gas inflow with a Bain circuit
(C) exhausted soda lime within a circle system
(D) absorption of carbon dioxide from carbon dioxide laparoscopy