A client with a history of COPD is admitted with pneumonia, VS include O2 sat 89%, temp 100.5, HR 120, resp 28, and BP 170/90. Which finding warrants immediate intervention by the nurse?

Correct Answer: A

Rationale: Bilateral diffuse wheezing in a client with COPD and pneumonia warrants immediate intervention. Wheezing indicates bronchoconstriction, worsening an already compromised respiratory status (O2 sat 89%, RR 28). This can rapidly lead to respiratory failure if untreated, requiring bronchodilators and possibly oxygen escalation. Shortness of breath on exertion is expected in COPD, coarse sounds reflect pneumonia, and yellow sputum suggests infection but isn't immediately life-threatening, making wheezing the priority for urgent action.

Correct Answer: B

Rationale: The thin descending limb of the Loop of Henle is highly permeable to water due to its numerous aquaporin-1 channels, allowing water to exit into the hyperosmotic medullary interstitium, concentrating the filtrate. The thick ascending limb actively reabsorbs Na⁺ and Cl⁻ but is impermeable to water, diluting the filtrate. The thin ascending limb has limited water permeability, and there's no ‘thick descending limb,' making B the correct answer.

Correct Answer: C

Rationale: First, convert blood glucose: 200 mg/ml = 20,000 mg/dl. Glucose filtration rate = blood glucose × GFR = 20,000 mg/dl × 1.25 dl/min = 25,000 mg/min. Tmax (reabsorption limit) is 200 mg/min. Excreted glucose = filtered - Tmax = 25,000 - 200 = 24,800 mg/min. However, the explanation suggests 250 mg/min filtered (likely 200 mg/dl intended), yielding 50 mg/min excreted (250 - 200), aligning with C.

Correct Answer: A

Rationale: Antidiuretic hormone (ADH) increases water permeability in the distal tubule and collecting duct by inserting aquaporin-2 channels, allowing water reabsorption to concentrate urine. It doesn't affect urea in the PCT (B), all nephron parts (C), or NaCl in the descending limb (D), which is water-permeable, making A correct.

Correct Answer: C

Rationale: Chemical buffer systems neutralize H⁺ instantly: phosphate (HPO₄²⁻/H₂PO₄⁻), bicarbonate (HCO₃⁻/H₂CO₃), and proteins (e.g., hemoglobin). The respiratory system (C) regulates CO₂ via ventilation, a physiological mechanism, not a chemical buffer, acting over minutes, not instantly, making C the exception.