Nokea
A patient with chronic lung disease is undergoing lung function testing. What test result denotes the volume of air inspired and expired with a normal breath?
- A. Total lung capacity
- B. Forced vital capacity
- C. Tidal volume
- D. Residual volume
Correct Answer: C
Rationale: The correct answer is C: Tidal volume. Tidal volume is the volume of air inspired and expired with a normal breath. It represents the normal breathing pattern without any additional effort. Total lung capacity (A) is the maximum amount of air the lungs can hold, Forced vital capacity (B) is the maximum amount of air exhaled forcefully after a maximal inspiration, and Residual volume (D) is the volume of air remaining in the lungs after a forced exhalation. Therefore, Tidal volume is the only choice that represents the volume of air inspired and expired during a normal breath.
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A nurse is caring for a client with emphysema who is receiving oxygen. The nurse assesses the oxygen flow rate to ensure that it does not exceed:
- A. 1 L/min
- B. 3 L/min
- C. 6 L/min
- D. 10 L/min
Correct Answer: B
Rationale: The correct answer is B: 3 L/min. Emphysema patients have compromised lung function, so high oxygen flow rates can lead to oxygen toxicity. 3 L/min is the recommended maximum flow rate to prevent oxygen toxicity while still providing adequate oxygenation. Choices A, C, and D exceed the safe limit and can lead to hyperoxia, absorption atelectasis, and other complications in emphysema patients. Therefore, B is the correct choice to ensure optimal oxygen therapy without causing harm.
In human beings, CO2 concentration in the inspired and expired air is respectively
- A. 0.03 % and 5.3 %
- B. 0.4 % and 5.0 %
- C. 0.04 % and 3.0 %
- D. 0.03 % and 4.0 %
Correct Answer: D
Rationale: The correct answer is D (0.03% and 4.0%). The inspired air contains approximately 0.03% CO2, as the atmosphere has a low CO2 concentration. During expiration, the CO2 concentration in the air increases due to the removal of oxygen and the addition of CO2 from cellular respiration, resulting in an average of around 4.0% CO2 in expired air. Choices A, B, and C are incorrect because they do not accurately reflect the typical CO2 concentrations in inspired and expired air in human beings.
Regarding airway resistance
- A. The Poiseulle equation denotes pressure volume characteristics for turbulent flow
- B. The very small bronchioles are the major site of resistance to airflow
- C. Decreased pCO2 in alveolar gas causes an increase in airway resistance
- D. As lung volume reduces, airway resistance reduces also
Correct Answer: C
Rationale: Rationale for Choice C: Decreased pCO2 in alveolar gas causes an increase in airway resistance:
1. pCO2 levels in alveolar gas directly affect bronchial smooth muscle tone.
2. Low pCO2 causes bronchodilation, leading to reduced airway resistance.
3. High pCO2 causes bronchoconstriction, increasing airway resistance.
4. This relationship is crucial in maintaining optimal ventilation-perfusion matching.
Summary for Other Choices:
A. Incorrect - Poiseuille's equation is for laminar flow, not turbulent flow, and describes the relationship between pressure, flow rate, and radius.
B. Incorrect - The major site of resistance is in medium-sized bronchi, not very small bronchioles.
D. Incorrect - As lung volume reduces, airway resistance actually increases due to decreased radial traction.
The nurse teaches the client that sublingual nitroglycerin should be taken
- A. Every two to three hours during the day
- B. At the first indication of chest pain
- C. Before every meal and at bedtime
- D. Only after 911 is called first
Correct Answer: B
Rationale: The correct answer is B - "At the first indication of chest pain." This is because sublingual nitroglycerin is a rapid-acting medication used to relieve chest pain related to angina by dilating blood vessels. Taking it at the first sign of chest pain ensures prompt relief. Choice A is incorrect as frequent dosing can lead to tolerance. Choice C is unnecessary and not evidence-based. Choice D delays treatment and can be dangerous in an emergency.
The theophylline blood level is 13 mcg/mL. Which intervention is the most appropriate in light of this finding?
- A. Give the next dose of theophylline as ordered.
- B. Skip the next dose, and then resume.
- C. Call the charge nurse or physician.
- D. Take the patient's blood pressure immediately.
Correct Answer: A
Rationale: The correct answer is A because the theophylline blood level of 13 mcg/mL is within the therapeutic range (10-20 mcg/mL). Therefore, the next dose should be administered as ordered to maintain therapeutic levels. Choice B is incorrect as skipping doses can lead to subtherapeutic levels. Choice C is unnecessary as the level is within range. Choice D is irrelevant to the theophylline level.