Persing TMC Practice| 160 QUESTIONS| WITH COMPLETE SOLUTIONS

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 inspiratory flow demands? A. 6L/min B. 8L/min C. 10L/min D. 12L/min correct answer: *B*, The air/O2 ratio 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. correct answer: *C*, As with adults, if the infant is hypoxemic with a normal or low PaCO2, increase the PaO2 by increasing oxygen to no more than 60%. Studies show that oxygen levels exceeding 60% increase damage to the lungs. If 60% doesn't reverse the hypoxemia, place the infant on CPAP. Hypoxemia on this oxygen percent indicates refractory hypoxemia, which won't improve with oxygen alone. Positive pressure is necessary to recruit collapsed alveoli and increase the surface area for gas exchange. Notice in this question that there is not a choice for 60%. However, do not choose 70% because it exceeds 60%. Mechanical ventilation is not necessary because the patient's PaCO2 is normal, which indicates adequate ventilation. correct 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. correct answer: A, An active 3-year-old generally tolerates a cannula much better than any kind of mask and is too large for an O2 hood. correct answer: B, If the patient is able to perform simple tasks when asked, this best determines his or her ability to follow instructions. This is important before administering an incentive spirometry or IPPB treatment, which requires the patient to be able to follow instructions well or the treatment will not be effective. correct answer: B, The best diagnostic test to determine whether a pulmonary embolism is present is the V/Q lung scan. correct answer: C, Alveolar minute ventilati