The plumbing problem is this: a man has a urinary catheter in situ, it won't come out. What are you going to do about it?
A 70 year old man presented with acute urinary retention. Insertion is difficult and ultrasound is used to ensure the catheter reaches the bladder before it is inflated.
An 83 year old woman with sepsis and acute kidney injury is being managed in your resuscitation area. A urinary catheter has been placed to monitor urine output. After an hour there is no urinary output at all.
A 68 year old male presents with frank haematuria and urinary retention. A 3 way indwelling urinary catheter (IDC) is inserted to enable a bladder washout. After initially draining some Shiraz coloured urine flow has slowed. You ultrasound the bladder to see what is going on.