Which of the following statements concerning use of temperature-corrected blood gas measurement (pH-stat) during hypothermic cardiopulmonary bypass is true?
(A) Blood gas analysis is performed at the patient's temperature
(B) Carbon dioxide should not be added to the bypass circuit
(C) The carbon dioxide content of the patient's blood is greater than it would be without temperature correction
(D) The incidence of postoperative neurologic deficits is increased compared with the alpha-stat method
(E) The patient's temperature should be maintained above 25°C
A full-term newborn has marked respiratory distress in the delivery room. Breath sounds are asymmetric and the abdomen is scaphoid. Which of the following maneuvers is most appropriate?
(A) Hyperventilation with bag and mask
(B) Intubation and ventilation with positive end-expiratory pressure
(C) Intubation and ventilation with zero end-expiratory pressure
A woman with chronic obstructive pulmonary disease is extubated and minimally responsive after isoflurane anesthesia. She is receiving oxygen 6 L/min through a face mask. Respirations are 10/min, PaO2 is 68 mmHg, PaCO2 is 54 mmHg, and pH is 7.28. The most likely cause of the respiratory acidemia is
(A) blunted sensitivity to low pH in the medullary respiratory center
(B) chronic carbon dioxide retention
(C) decreased lung volume from supine positioning
(D) depression of carotid body chemoreceptors by halothane
(E) suppression of hypoxic ventilatory drive by supplemental oxygen
A 5-year-old child undergoes strabismus correction during spontaneous ventilation with halothane 1.5%, nitrous oxide and oxygen 50%. Intravenous atropine 0.2 mg is administered after inhalation induction. Ten minutes after incision, heart rate decreases from 110 bpm to 40 bpm. Which of the following is the most likely cause?
(A) Administration of phenylephrine eyedrops
(B) Inadvertent external pressure on the carotid sinus
(C) Paradoxical response to a small dose of atropine
During uncomplicated mask induction with halothane and 50% nitrous oxide in oxygen in a 6-month-old infant with a large ventricular septal defect and valvular pulmonic stenosis, SpO2 decreases from 85% (room air) to 60%; heart rate is 100 bpm and blood pressure is 62/40 mmHg. The most appropriate management is to
An atrioventricular sequential demand pacemaker is placed in a patient who has abnormal atrioventricular conduction. Each of the following statements about this situation is true EXCEPT:
(A) Electrocautery could lead to long pauses in the paced rhythm
(B) Placing a magnet over the generator will convert it to an asynchronous (fixed rate) unit
(C) If complete heart block develops, the paced ventricular rate will be the same as the sinus node rate
(D) An atropine-induced increase in the sinus rate will increase the ventricular rate
(E) During symptomatic tachyarrhythmia, cardioversion would be contraindicated because it would alter the pacemaker's function