A 73-year-old man who slipped on a small carpet in his home and fell on his hip is alert and oriented; PERRLA (pupils equally round and reactive to light and accommodation) is intact, and he has come by ambulance to the emergency department (ED). Heart rate elevated, he is anxious and thirsty. A Foley catheter is in place and 40mL of urine is present. The nurse's most likely explanation for the urine output is:
Correct Answer: D
Rationale: Renin is released by the juxtaglomerular cells of the kidneys in response to decreased renal perfusion. Angiotensin-converting enzyme converts angiotensin I to angiotensin II. Angiotensin II, with its vasoconstrictor properties, increases arterial perfusion pressure and stimulates thirst. As the sympathetic nervous system is stimulated, aldosterone is released in response to an increased release of renin, which decreases urine production. Based on the nursing assessment and mechanism of injury, this is the most likely cause of the lower urine output.