The stem
A 72-year-old man cannot pass urine on the first day after an inguinal hernia repair. His bladder is palpable. You are asked to prepare this.
The equipment
The examiner’s questions
Question 1What is this, and what is it used for?Show the model answer
A two-way Foley urinary catheter. One channel drains urine; the other fills the retaining balloon. It is used for urinary retention, to measure urine output hourly in sick or post-operative patients, during long operations, and to rest the bladder after some urological procedures.
Question 2What does the number 16 mean?Show the model answer
The size in French or Charrière units, which is the outer circumference in millimetres, so a 16 Ch catheter is about 5.3 mm across. Adults usually take 12 to 16 Ch. A three-way catheter of larger size, usually 20 to 24 Ch, is used for bladder irrigation in clot retention.
Question 3Describe the key steps of insertion.Show the model answer
Consent and a chaperone. Aseptic technique, clean the meatus and instil lidocaine gel, and wait for it to work. Insert the catheter fully until urine flows, and only then inflate the balloon with 10 mL of sterile water. Connect the bag, record the residual volume, and in a man replace the foreskin.
Question 4What are the complications?Show the model answer
Catheter-associated urinary tract infection, which is the commonest; urethral trauma and a false passage; inflating the balloon in the urethra; paraphimosis if the foreskin is not replaced; blockage; and later urethral stricture. Do not pass a urethral catheter if a urethral injury is suspected, such as blood at the meatus after trauma.
After you answerThe teaching pointShow
If no urine comes back, do not inflate the balloon. Check the catheter is fully inserted, or that the bladder is actually full.
The drawings were made for this site. The patients are written for teaching and are not real.