On auscultation, which finding suggests a right pneumothorax?

Correct Answer: B

Rationale: The correct answer is B because in a right pneumothorax, there is a loss of breath sounds on auscultation due to air in the pleural space preventing lung expansion and sound transmission. This absence of breath sounds is a classic finding in pneumothorax. A: Bilateral inspiratory and expiratory crackles are indicative of conditions like pneumonia or pulmonary fibrosis, not pneumothorax. C: Inspiratory wheezes suggest conditions like asthma or bronchitis, not pneumothorax. D: Bilateral pleural friction rub is typically heard in conditions like pleurisy or pleural effusion, not pneumothorax.

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.

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.

Correct Answer: A

Rationale: The correct answer is A: 21 percent. Air is composed of about 21% oxygen, 78% nitrogen, and small amounts of other gases. This composition is crucial for sustaining life on Earth. Choice B is incorrect as it represents the percentage of nitrogen in the air. Choices C and D are also incorrect as they are the approximate percentages of carbon dioxide and argon in the air, respectively. Therefore, the correct answer is A as it accurately reflects the oxygen content in the air.

Correct Answer: D

Rationale: The correct answer is D because the rate and depth of breathing are controlled by a respiratory center in the brainstem, which includes the medulla and pons. The medulla regulates the basic rhythm of breathing, while the pons helps adjust the rate and depth based on input from chemoreceptors and other factors. Choice A is incorrect because chemoreceptors in arterial walls primarily detect changes in blood pH and CO2 levels, not directly control breathing. Choice B is incorrect as baroreceptors in the diaphragm are more related to detecting stretch and pressure changes, not regulating breathing. Choice C is incorrect as the partial pressure of O2 in the atmosphere does not directly control breathing but rather influences oxygen exchange in the lungs.