In a man undergoing surgery, it was necessary to aspirate the contents of the upper gastrointestinal tract. After surgery, the following values were obtained from an arterial blood sample: pH 7.55, PCO2 52 mm Hg and HCO3- 40 mmol/l. What is the underlying disorder?

Correct Answer: C

Rationale: A pH of 7.55 (alkalosis), PCO₂ of 52 mmHg (elevated), and HCO₃⁻ of 40 mmol/L (high) indicate metabolic alkalosis, likely from loss of gastric acid (H⁺) via aspiration, raising HCO₃⁻. Elevated PCO₂ reflects respiratory compensation (hypoventilation). Respiratory alkalosis (B) has low PCO₂, acidosis (A, D) has low pH, making C correct.

Correct Answer: D

Rationale: A multifaceted approach to impaired urinary elimination (e.g., history, symptoms, exams) provides comprehensive insights (D), enabling tailored interventions (e.g., catheterization, medication) for effective management. It doesn't simplify diagnosis (A), isn't history-only (B), and goes beyond streamlining (C), making D the accurate understanding.

Correct Answer: D

Rationale: Prostaglandins, dopamine, and bradykinin dilate vessels (A), ADH, angiotensin II, and epinephrine constrict (B), and the balance with cardiac factors regulates BP (C). All are true—vasodilators lower resistance, vasoconstrictors raise it, and these with heart output set BP—making E (all are correct), reassigned as D, correct.

Correct Answer: B

Rationale: The kidneys filter ~180 liters of glomerular filtrate daily (B) in adults, based on a GFR of 125 mL/min (180 L/day), far exceeding urine output due to reabsorption. 1,000 L (A) is excessive, 110 L (C) underestimates, and 7.5 L (D) is too low, making B the correct physiological value.

Correct Answer: C

Rationale: High ADH increases collecting duct permeability to water (C) via aquaporin-2, concentrating urine. They remain impermeable to water without ADH (A), proteins (B) are not filtered, and sodium/chloride (D) are regulated elsewhere, making C the effect of ADH.