A sputum study has been ordered for a patient who has developed coarse chest crackles and a fever. At what time should the nurse best collect the sample?

Correct Answer: B

Rationale: The correct answer is B: First thing in the morning. Sputum should be collected in the morning because it is usually more concentrated, making it easier to obtain a good sample. This is important for accurate analysis and identifying potential pathogens causing the patient's symptoms. Collecting sputum immediately after a meal may result in contamination with food particles. At bedtime, sputum may have accumulated overnight, but morning samples are still preferred due to concentration. Collecting sputum after a period of exercise may introduce respiratory secretions not reflective of the underlying condition.

Correct Answer: A

Rationale: Step 1: Blood flow supplies oxygen and removes carbon dioxide in the lungs, essential for efficient gas exchange. Step 2: Decreased blood flow means less oxygen delivery and carbon dioxide removal, leading to decreased respiratory efficiency. Step 3: Choice A is correct as it directly impacts the gas exchange process. Summary: - Choice B (increased surface area) would enhance gas exchange efficiency. - Choice C (increased partial pressure gradients) would improve gas exchange efficiency. - Choice D (increased gas solubility) would not directly affect respiratory efficiency.

Correct Answer: C

Rationale: The correct answer is C because the Dorsal Respiratory Group (DRG) and Ventral Respiratory Group (VRG) are the centers in the brainstem responsible for controlling the rate and depth of breathing. The DRG primarily regulates inspiration, while the VRG is involved in both inspiration and expiration. The apneustic and pneumotaxic centers (choices A and B) are subregions within the pons that modulate the activity of the DRG and VRG but do not establish the baseline rate and depth of breathing. The expiratory center (choice D) is responsible for controlling only the expiratory phase of breathing and is not involved in setting the normal rate and depth of breathing.

Correct Answer: D

Rationale: The correct answer is D. Inhibition of medulla oblongata chemoreceptors and respiratory muscles would decrease respiratory rate, leading to decreased elimination of CO2 at alveoli. This would cause an increase in arterial PCO2 due to less CO2 being removed from the body. Therefore, choice D is correct. Choices A, B, and C are incorrect because they do not align with the physiological effects of inhibiting the medulla oblongata chemoreceptors and respiratory muscles. Option A suggests an increase in respiratory rate and elimination of CO2, which goes against the expected decrease in these parameters. Option B proposes an increase in respiratory rate but a decrease in CO2 elimination and arterial PCO2, which is inconsistent with the expected outcomes. Option C suggests an increase in respiratory rate and CO2 elimination but a decrease in arterial PCO2, which does not follow the logic of the question.

Correct Answer: C

Rationale: The correct answer is C: atelectasis. Atelectasis refers to the collapse of a lung or a part of a lung, leading to incomplete expansion of air sacs. This can be caused by various factors such as blockage of the airways or compression of the lung tissue. Pleurisy (A) is inflammation of the pleura, the lining around the lungs. Pleural effusion (B) is the accumulation of fluid in the pleural space. Pneumothorax (D) is the presence of air in the pleural space, leading to lung collapse. Atelectasis specifically describes the collapse of the lung itself, making it the correct choice.