Which catheter, and is it even indicated?
The exam frequently starts before the procedure by asking whether a catheter is appropriate at all. Acceptable indications include acute urinary retention or bladder outlet obstruction, accurate strict output measurement in critically ill clients, selected perioperative needs, healing of open sacral or perineal wounds in an incontinent client, prolonged immobilisation such as an unstable spine, and comfort at end of life. Incontinence by itself, staff or family convenience, and routine specimen collection are not indications, and an option offering a catheter for those reasons is wrong.
Device choice follows purpose. A straight or intermittent catheter drains the bladder once and is preferred for residual volume measurement, intermittent management of neurogenic bladder and one-off retention, because it carries less infection risk than an indwelling line. An indwelling Foley has a retention balloon inflated with sterile water and remains in place for continuous drainage. A three-way catheter has an extra lumen for continuous bladder irrigation after transurethral prostate surgery. A suprapubic catheter enters through the abdominal wall and is used for long-term drainage or urethral trauma. External devices — a condom catheter for men or an external female wicking device — manage incontinence without entering the urethra and are the safest answer whenever the client simply needs containment.
Size matters less than students expect but does appear: a 14 to 16 French catheter suits most adults, larger three-way catheters are used for irrigation with clots, and paediatric sizes are much smaller. The balloon is inflated only with sterile water, never saline, which can crystallise and block deflation, and never air, which floats and fails to seat the balloon.
| Device | Best use | Key nursing point |
|---|---|---|
| Intermittent (straight) | Residual volume, neurogenic bladder, one-off retention | Lowest infection risk; teach clean self-catheterisation at home |
| Indwelling Foley | Retention, strict output, sacral wound healing | Review need daily; remove as soon as possible |
| Three-way | Continuous bladder irrigation post-TURP | Subtract irrigant from total output |
| Suprapubic | Long-term drainage, urethral injury | Sterile site care; keep insertion site dry |
| External (condom or wicking) | Incontinence without retention | No urethral entry; check skin integrity every shift |
Sterile insertion, step by step
Insertion is a sterile procedure, and the exam tests sequence. Verify the order and identify the client with two identifiers, explain the procedure and provide privacy, perform hand hygiene, and position the client — supine with knees flexed and hips externally rotated for a female client, supine with legs slightly apart for a male client. Adequate lighting and an assistant for positioning are legitimate answers when the client cannot cooperate.
Open the kit maintaining a sterile field, don sterile gloves, and place the drape. Cleanse with the non-dominant hand, which is now contaminated and must not leave the labia or retracted foreskin until the catheter is inserted. Clean the female client front to back, one swab per stroke, labia first and meatus last; clean the male client in circular strokes from the meatus outward. Lubricate generously and insert with the dominant sterile hand: two to three inches in a female client, or advance the male catheter six to nine inches with the penis held at a ninety-degree angle to straighten the urethra.
Advance until urine returns, then advance a further one to two inches before inflating the balloon so the balloon sits in the bladder, not the urethra. Inflate with the prefilled sterile water syringe, tug gently to seat the balloon at the bladder neck, secure the catheter to the thigh or abdomen to prevent traction, and hang the bag below bladder level on the bed frame. If no urine returns, leave the catheter in place, confirm placement, and try again with a new sterile catheter rather than reusing the contaminated one.
- •Sterile gloves, sterile field, prefilled sterile water for the balloon
- •Non-dominant hand stays in place once cleansing begins
- •Advance 1–2 inches past urine return before inflating
- •Never inflate a balloon against resistance or before urine flow
- •Secure the tubing to prevent traction on the urethra
- •If the catheter enters the vagina, leave it as a landmark and insert a new sterile catheter
Maintenance and CAUTI prevention
Once in place, nursing care is about protecting a closed system. Keep the bag below the bladder at all times, including during transfers and ambulation, and never rest it on the floor. Coil tubing on the bed without dependent loops so urine drains by gravity, empty the bag when two-thirds full using a separate clean container per client, and avoid touching the drainage spout to the container.
Daily hygiene is soap and water to the meatus and perineum, not antiseptics, which irritate tissue without reducing infection. Encourage fluids of two to three litres a day unless contraindicated to maintain flow. Do not irrigate routinely, do not change the catheter on a fixed schedule, and do not disconnect the tubing to obtain a specimen — a sterile sample is aspirated from the needleless sampling port after clamping briefly and disinfecting the port.
The most tested intervention of all is removal. Every shift the nurse asks whether the catheter is still indicated, and nurse-driven removal protocols exist precisely because duration drives infection. After removal, monitor for the first void within six to eight hours, expect transient dysuria and urgency, and bladder scan if the client has not voided or reports fullness. Retention after removal is managed with scanning and intermittent catheterisation before an indwelling line is replaced.
Complications, irrigation and clinical judgement
No urine output through a catheter is an assessment, not a call: check for kinks, dependent loops, a closed clamp and a full bag, then palpate or scan the bladder. A distended bladder with a dry catheter means obstruction, often from clots or sediment, and the provider is notified for an irrigation order. An empty bladder with no output points instead to poor perfusion or acute kidney injury, and vital signs and creatinine matter more than the catheter.
After transurethral prostate resection, continuous bladder irrigation runs to keep urine light pink and free of clots. The irrigant volume is subtracted from total drainage to calculate true urine output, the rate is titrated to the colour of the drainage, and bright red drainage with clots or a sudden fall in output with bladder spasm and distension means the provider must be informed. Bladder spasms are expected and treated with antispasmodics, not by pulling on the catheter.
Other tested complications include urethral trauma from traction, which is prevented by securing the tubing; balloon failure to deflate, which is escalated rather than forced; and CAUTI itself, presenting with fever, suprapubic or flank pain, cloudy malodorous urine, and in older adults new confusion. New-onset confusion in an older client with a catheter should always raise infection as a possibility rather than being attributed to age.
How the exam frames catheter questions
Priority items ask what to do first when output stops, and the correct answer is almost always an assessment step — check the tubing, scan the bladder — before notifying anyone. Safety items test sterile technique breaks, and the answer is to stop and restart with new sterile supplies rather than continue. Delegation items ask what unlicensed assistive personnel may do: they may provide perineal care, empty the bag and record output, but they do not insert catheters in most jurisdictions, do not perform the sterile specimen collection, and do not assess.
Teaching items focus on home care and intermittent self-catheterisation, where clean rather than sterile technique is acceptable, hand hygiene is essential, catheters are cleaned and reused per protocol, and the client reports fever, cloudy urine or inability to pass the catheter. Reinforce fluid intake and a regular catheterisation schedule to prevent overdistension.
Practise these scenarios in mixed sets so that catheter content appears without warning, exactly as it will on the exam, and review every rationale to see which principle — sterility, gravity drainage, closed system or early removal — drove the correct answer.