Urethral Obstruction

Question 1

What is the most life threatening aspect of urethral obstruction?

Answer 1

Hyperkalemia resulting fin lower rate of myocardial depolarization leading to bradycardia (and asystole at high levels).

Question 2

What are the post renal electrolyte imbalances?

Answer 2

Hyperkalemia, hyperphosphatemia, azotemia, increased creatinine and metabolic acidosis due to reduction of glomerular filtration rate resulting from back pressure transmitted up the ureters from the bladder

Question 3

What IV fluids would you use to counteract metabolic acidosis?

Answer 3

A balanced electrolyte solution with alkalizing effect such as Normosol-R

Question 4

What analgesic drugs should you avoid in urethral obstruction patients?

Answer 4

Alpha -2 agonist such as xylazine and dexmedetomidine - concerns with bradyarrhythmias

Question 5

What induction agents are favorable in urethral obstruction patients?

Answer 5

Etomidate - minimal cardiovascular depression
Propofol - in hemodynamically stable patients
Ketamine - in patients without cardiac disease

Above combined with a benzodiazepine

*Avoid repeat doses of ketamine as active metabolite (norketamine) is excreted in kidneys, renal dysfunction caused by obstruction will prolong effects until it is relieved