THERAPIST MULTIPLE-CHOICE EXAMINATION: PRACTICE TEST

THERAPIST MULTIPLE-CHOICE EXAMINATION: PRACTICE TEST The physician orders a 35% aerosol mask to be set up for a patient who requires an inspiratory flow of 42 L/min. What is the minimum flow rate to which the flowmeter must be set to meet this patient's in- spiratory flow demands? A. 6 L/min B. 8 L/min C. 10 L/min D. 12 L/min - ANSWER B, The air/O2ratio for a 35% oxygen mixture is 5 : 1. To calculate total flow output from this device, add the ratio parts together and multiply by the liter flow: 6 ×6 = 36 L/min, 6 ×8 = 48 L/min, 6 × 10 = 60 L/min, 6 ×12 = 72 L/min. Total flow needed: 42 L/min. The minimum flow necessary is 8, giving a total flow of 48 L/min. (Analysis) A premature 3-week-old infant is receiving 1 L/min of O via a nasal cannula and has a PaO of 43 torr22 and a PaCO2 of 40 torr. The respiratory therapist should recommend which of the following? A. Increase the cannula flow to 2 L/min. B. Intubate and institute mechanical ventilation C. Initiate CPAP of 4 cm H2O and 50% O2 D. Increase the cannula flow to 5 L/min. - ANSWER A, A PaO2 of 43 torr represents hypoxemia. The normal PaO2 for an infant is 50-70 torr. Increasing the cannula flow by 1 L/min is the most appropriate choice to return the PaO2 to normal. With a normal PaCO2 of 40 torr, mechanical ventilation is not indicated. (Analysis) what is normal PaO2 for infant ? - ANSWER 50-70 torr. A patient arrives in the emergency department after being pulled from a burning house. The respiratory therapist should recommend obtaining which of the following measurements to best determine the sever- ity of the patient's smoke inhalation? A. SpO2 B. HbCO C. PaO2 D. Hb - ANSWER B, To best determine the severity of smoke inhalation, an HbCO level should be determined with a co-oximeter. The SpO2 value should never be evaluated on a patient suspected of CO poisoning because a pulse oximeter is not capable of determining what is bound to hemoglobin. Pulse oximeters work on the principle of spectrophotometry where lightweight probes direct filtered light of specific wavelengths through the skin or digit. The light absorbed differs for saturated and desaturated blood, whether it's saturated with oxygen or a combination of oxygen and carbon monoxide. Therefore the reading will be erroneously high when HbCO is present. (Analysis)