A 72 YEAR OLD MAN IN ICU HAD AN ABDOMINAL AORTIC ANEURYSM REPAIR EIGHT HOURS AGO. IN THE LAST HOUR, HE HAS PASSED 10ML OF URINE VIA A CATHETER. HIS PULSE RATE IS 125 BPM AND BP 70/50MMHG. WHICH IS THE SINGLE MOST LIKELY DIAGNOSIS

• A. Acute renal failure
• B. Blocked catheter
• C. Cardiogenic shock
• D. Hypovolaemia ✓
• E. Sepsis

Given the clinical scenario described, the most likely diagnosis for the 72-year-old man in the ICU who had an abdominal aortic aneurysm repair eight hours ago is hypovolemia. Here’s a breakdown of why hypovolemia is the single most likely diagnosis based on the presented information:

1. Urine Output: The fact that the patient has only passed 10ml of urine in the last hour suggests decreased renal perfusion, which can be a sign of hypovolemia. Inadequate blood volume can lead to reduced kidney function and decreased urine output.
2. Pulse Rate: A pulse rate of 125 bpm is elevated and can be a compensatory mechanism in response to decreased blood volume (hypovolemia). The body tries to maintain perfusion by increasing heart rate to improve cardiac output.
3. Blood Pressure: A blood pressure of 70/50 mmHg is low and indicative of poor perfusion to vital organs, which aligns with hypovolemic shock where there is insufficient circulating blood volume to adequately perfuse tissues.
4. Abdominal Aortic Aneurysm Repair: The surgical repair of an abdominal aortic aneurysm can lead to significant fluid shifts and potential blood loss during the procedure, predisposing the patient to hypovolemia postoperatively.
5. Clinical Picture: When considering all the presented symptoms together – low urine output, tachycardia, and hypotension – they collectively point towards hypovolemia as the primary issue affecting this patient’s condition.

In summary, given the context of recent surgery, low urine output, tachycardia, and hypotension, hypovolemia emerges as the most probable diagnosis in this case.

In other words, Hypovolaemia refers to a decrease in blood volume circulating through the body. In this case, the low urine output, elevated heart rate (tachycardia), and low blood pressure (hypotension) are indicative of hypovolaemia. The surgical repair of an abdominal aortic aneurysm can lead to significant fluid loss and decreased blood volume, resulting in hypovolaemia.