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 30-year-old, 70-kg woman with mitral stenosis is scheduled for elective laparoscopic sterilization. Preoperatively she is taking digoxin and an unknown medication for chronic mental depression. The EKG demonstrates atrial fibrillation. Heart rate is 68 bpm. Anesthesia is induced with thiopental followed by nitrous oxide 50%, halothane 0.75%, and a continuous succinylcholine infusion. The ventilator is set to deliver a minute volume of 5 liters through an endotracheal tube. As the carbon dioxide is being insufflated into the abdomen, the blood pressure is noted to be elevated (150/100 mmHg) and ventricular bigeminy is present. The most appropriate therapy is to
(A) increase the halothane concentration to 1.25%
(B) discontinue the succinylcholine infusion
(C) increase minute ventilation to 7.5 L/min
(D) administer potassium 5 mEq intravenously over one minute followed by propranolol 0.25 mg
(E) measure arterial blood gas and serum electrolyte values
An air/oxygen blender with E-size cylinders is supplying gas to a Mapleson D circuit being used to ventilate a neonate during transport. The air tank is full (psi= 1900/625 L) and flow is 4 L/min. The oxygen tank flow is 5 L/min and the pressure gauge indicates 500 psi. If the flow rates remain unchanged, which of the following statements is correct?
(A) The air tank will be empty in 90 minutes
(B) The oxygen tank will be empty in 30 minutes
(C) The concentration of oxygen in the circuit is 60%
(D) The oxygen tank will fill with air when the pressure gauge falls below 50 psi
(E) The volume of oxygen remaining can be determined only by weighing the tank
Which of the following statements best describes "screening" when blood is ordered for type and screen?
(A) Red blood cells are mixed with serum containing known antigens
(B) Red blood cells are mixed with serum from the pool of potential donors
(C) Red blood cells are mixed with red blood cells from the pool of potential donors
(D) Serum is mixed with red blood cells that contain known antigens
(E) Serum is mixed with red blood cells from the pool of potential donors
D
A 120-kg 56-year-old man undergoing gastrectomy during anesthesia with fentanyl and isoflurane has a PetCO2 of 35 mmHg and a PaCO2 of 50 mmHg. His FEV,/FVC ratio is 80% of predicted. Heart rate is 120 bpm and arterial blood pressure is 80/40 mmHg. Which of the following is the most likely cause of the difference in PaCO2 and PetCO2?