Urinary Catheters

Snapshot: This document provides an overview of urinary catheters, along with catheter types, sizing, indications, insertion and removal instructions, and complications and troubleshooting. Also included is a brief library of video links that demonstrate how to perform this skill.

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Instructional Videos for Urinary Catheters What Is a Catheter? Catheter Types Catheter Sizing Indications for a Catheter Inserting a Catheter Catheter Complications Troubleshooting Catheter Care Removing a Catheter

Instructional Videos for Urinary Catheters

What Is a Catheter?

  • Urinary catheters are latex, polyurethane or silicone tubes inserted into the bladder via the urethra for the purpose of draining or collecting urine.
  • Catheters can be placed either temporarily or permanently.
  • In healthcare settings, they are usually inserted, cared for, and removed by nurses. In more complex cases, urologists will sometimes manage catheters.

Catheter Types

  • Foley Catheters. These are ‘standard’ indwelling catheters, retained in the bladder with an inflatable saline balloon.
  • Intermittent Catheters. These are catheters for short-term drainage of urine. Unlike Foley Catheters, they do not have inflatable balloons, and therefore must be held in place, usually for one-time use.
  • Coude Catheters. These catheters are made of stiffer material than other catheters, and have a curved tip at their end that allows them to slip past urethral obstructions.
  • External “condom” catheters (sometimes called “Texas” catheters). These catheters slip over the outside of the penis, and are therefore not inserted into the urethra. They carry a lower risk of infection, although they are at higher risk of falling off than indwelling catheters.

Catheter Sizing

  • Catheter sizes are measured according to the French catheter scale (F). Most catheters are between 10 F (3.3 mm) and 28 F (9.3 mm). 16 Fr and 18 Fr are especially common catheter sizes.
  • The French catheter scale corresponds to the diameter of the catheter in millimeters, divided by three. For example, a size 18 French (F) catheter will have a diameter of 6 mm, a size 30 French (F) catheter will have a diameter of 10 mm, and so on.
  • The overall goal of catheter sizing is to choose a catheter size that is large enough to allow urine to drain, but not so large as to damage the urethra.
  • Narrower catheters are more likely to get clogged (especially for patients with a lot of sediment in their urine), but they also exert less pressure on the urethra.

Indications for a Catheter

  • Catheters are invasive and sometimes uncomfortable, and indwelling catheters, in particular, always carry a risk of infection. Catheters should only be inserted if there is a valid clinical reason for doing so, and not simply for the convenience of the nurse or other medical staff.
  • Before you insert a catheter, ask yourself whether the patient could use a bedside commode, a urinal, or a bedpan instead.
  • If the answer is “no,” the following is a list of common, valid clinical reasons for inserting a urinary catheter:
    • To accurately measure urine output
      • While catheters are not the only way to measure urine output, they are a precise way to do so, especially for patients who cannot reliably collect and save their own urine. Urinary output is an important indicator of volume status and renal perfusion, and therefore of physical health.
    • Urinary incontinence
      • For patients who cannot control their urge to urinate, or who are not able to get to a bathroom in time to urinate, catheters solve an important problem. (For patients who are able to ambulate, most indwelling catheters come with a smaller ‘leg’ bag, which can be attached via a strip directly to a patient’s leg, thereby allowing an incontinent person to walk freely while still wearing their catheter).
    • Urinary retention 
      • Catheters provide a way of relieving urinary retention, which can be very dangerous if the bladder becomes over-stretched. Urinary retention can be caused by a variety of medical conditions, and by certain medications (e.g. anesthesia, opioids, and paralytics).
    • Bladder obstruction
      • Closely related to urinary retention, for patients with bladder obstructions due to various causes – such as prostate enlargement secondary to benign prostatic hypertrophy (BPH), blood clots, or urethral compression – catheters provide a ‘tract’ through which urine can flow normally.

Inserting a Catheter

  • First, find a Foley Catheter kit (which should contain most of your needed supplies), and a towel or chux, and explain the procedure to the patient. Allow time for the patient to ask questions, especially if they have never had a catheter before.
  • If you’re new at this procedure, it’s often helpful to enlist the help of another nurse. You should also bring in an extra Foley Catheter kit, in case you need it.
  • Wash your hands, then assist patient to a supine position. If the patient is female, help her into a “frog leg” position with knees bent and legs spread apart. If the patient is male, his legs may be loosely open.
  • Open the catheterization kit, remove the sterile drape, and place it over the procedure area. Put on the sterile gloves inside the kit. Note: some nurses prefer to bring their own sterile gloves, as they find those inside the catheter kits do not fit as well.

  • Check the saline balloon for patency by attaching it to the “Y” pigtail port on the catheter, inflating it, then deflating it. Most catheter balloons require 5-10 cc’s of saline to be fully inflated. This step is important because if the balloon does not function properly, the catheter will not stay in place.
  • Coat the distal portion of the catheter with lubricant (included in the kit). Some nurses prefer to leave the tip of the catheter inserted in the packet of lubricant, as this minimizes mess and spillage.
  • If the patient is female, separate the labia using your non-dominant hand. If the patient is male, hold the penis with your non-dominant hand.
  • Using your dominant (sterile) hand, cleanse the peri-urethral mucosa with cleansing solution, usually betadine. Note: in some kits, swabs are pre-coated with betadine, and others require you to squeeze some betadine over cotton balls, which can be done inside the sterile catheter tray. Using your betadine swabs or cotton balls, cleanse anterior to posterior, and inner to outer, using one swab per swipe. Discard the used swabs or cotton balls away from the sterile field.

  • Using your dominant (sterile) hand, pick up the lubricated catheter. If the patient is female, you should be able to locate the urethra by looking for a small opening just above the vagina, and below the mons pubis. When coated with betadine, the urethra may appear to ‘wink’ or glisten underneath.
  • If the patient is male, hold the penis upright, i.e. perpendicular to the patient’s body; if the man is uncircumcised and has foreskin, gently retract it. The female can remain in the supine, “frog leg” position.
  • Insert the catheter into the urethra, and gently advance the catheter until you see a “flash” of urine in the catheter tubing. Then, advance it 1 – 2 inches further, and inflate the saline balloon.
  • If you are unsuccessful and do not see a flash of urine, try again, but do not ever force the catheter.

  • Once you have inserted the catheter, to verify placement gently tug on the end of the catheter to ensure the saline balloon is inflated up against the neck of the bladder.
  • Connect the catheter to the drainage device. Place the drainage bag below the level of the bladder, but not on the floor. Attach it to the bed frame, not the bedrails; if attached to the bedrails, the bag could elevate and the catheter could become dislodged if the bed is raised or lowered too much.
  • Evaluate the color and type of urine output. Document the size of the catheter you inserted, how the patient tolerated the procedure, and the quality and quantity of urine output.
  • Before leaving the room, gather your supplies, dispose of them, and wash your hands.

Catheter Complications

While routine in many healthcare settings, inserting a Foley catheter nonetheless always carries certain risks of which RN’s should be aware.

  • Infection. Bacterial infection is the most common, and arguably the most serious, complication from indwelling catheters. Catheter-associated urinary tract infections (CAUTI) are among the most common nosocomial (hospital acquired) infections, are very common in patients with catheters in the home setting too. Untreated UTI’s may lead to renal inflammation, and even sepsis.
    • Symptoms of a CAUTI may include pain or burning during urination , itching, cloudy or foul-smelling urine, and especially in older patients, who may not display these ‘classic’ symptoms, changes in mental status.
    • Because the female urethra is shorter than the male urethra, UTI’s are more easily acquired and more common in females.
    • Even if perfect sterile technique is employed, research demonstrates that virtually all indwelling catheters become colonized with bacteria. (This does not mean that all catheterized will develop an infection). Some research shows that use of silver alloy and silicone catheters may reduce the risk of CAUTI.
    • The best way to avoid unnecessary introduction of bacteria, and to increase the risk of infection, is by practicing sterile catheter insertion technique, and through proper care and maintenance of indwelling catheters (see the “Catheter Care” section below).
  • Tissue trauma. This usually occurs as a result of the catheter tubing scraping against the urethra during catheter insertion. After the catheter is inserted, you may observe pink-tinged or trace amounts of blood in the patient’s urine.
    • Tissue trauma can be avoided by using a correctly sized catheter that has been generously lubricated, and by not ‘forcing’ catheter insertion. Tissue trauma usually resolves spontaneously.
  • Allergic sensitization. Most patients are not allergic to polyurethane or latex (the most common materials from which catheters are made). However, even some non-allergic patients who have indwelling catheters for longer periods of time, i.e. 14 days or more, may become sensitized or allergic to this material.
    • For such patients, silicone or hydrogel catheters may be a good alternative.
  • Urethral perforation, or other major trauma. Rarely, catheterization can result in more serious trauma. This is almost always due to improper catheterization technique, or attempting to force a catheter past a urethral obstruction. Surgery may be necessary to correct this more serious potential complication.


Patients with catheters may encounter any number of challenges. Most are routine, as long as you know how to handle them. Here are a few of the most common problems:

  • Little or no urine output. The human body should produce some urine (an average output of at least 30 millileters per hour) every 6 – 8 hours. If a catheterized patient begins producing little or no urine, the cause must be either some change in renal function, or may be due to a problem with the catheter.
    • First, check the catheter tubing for kinks. If the tubing is bent, it may be blocking urine output. Also check to see if the patient may be inadvertently lying or sitting on the catheter tubing. Often simply re-positioning the catheter tubing can help urine to flow again.
    • Consider flushing the catheter, especially if it has been a long time since the catheter was changed, or if you notice dark, concentrated urine with sediment in the catheter bag. (For instructions on how to flush a catheter, see the “Catheter Care” section below).
    • If neither of these interventions is appropriate or leads to urine output, consider using a bladder scanner to check for urinary retention. This is important because a distended bladder can lead to hydronephrosis, i.e. urine backing up into the kidney. A patient experiencing severe hydronephrosis may exhibit flank pain (pain between the hips and ribs); left untreated, hydronephrosis may lead to renal failure.
    • If the catheter is not clogged and no urinary retention is present, consider changes in the patient’s clinical status that may have caused anuria (no urine production) or oliguria (small urine production), and collaborate with your physician and medical team as appropriate to formulate a plan of care.
  • Leaking. Catheters usually leak in one of two ways: chronic, slow leaks, and sudden, large leaks. The strategies for handling each type of leak are different.
    • If the catheter has a chronic, slow leak, a patient may simply need a larger size catheter, or the catheter may need to be changed. If the catheter tubing and the inflatable saline balloon are not secure against the neck of the bladder, urine will leak out around the edges of the catheter.
    • If the catheter has a sudden, large leak, the catheter tubing may have become kinked, or the patient may be having bladder spasms. Check for kinks as described above (i.e. by checking for bends in the tubing, or if the patient may be inadvertently sitting on the catheter). If the tubing is not kinked, consider treating the bladder spasms with a medication such as oxybutynin. Do not increase the catheter size for sudden, large leaks, as an increased catheter size could exacerbate bladder spasms, and will not fix the underlying problem.
  • Pain or discomfort. A properly placed and functioning catheter should not be painful.
    • First, check to see if the discomfort is positional. After making sure the catheter is in place, you can ask the patient to try to stand (if they are able), or to gently change position while seated or in bed. If this is painful, the catheter may be irritating the bladder. Consider changing the catheter, and use a smaller size catheter if you are able.
    • If the discomfort is not positional, ask the patient to describe the discomfort. If they report burning or painful urination, if their urine is cloudy or foul-smelling, or if you notice confusion or mental status changes (especially in elderly patients), consider a urinary tract infection as the cause. Speak to your physician or medical team about removing the catheter and starting the patient on an antibiotic.

Catheter Care

While proper catheter care is important for all patients with indwelling catheters, it is especially crucial for those individuals who have catheters long-term, as the risk of infections and other complications increases over time. Below are some important general guidelines to keep in mind:

  • Wash your hands. Always do this before and after performing catheter care. This is the simplest but most powerful means available of reducing the risk of infection.
  • Clean the catheter daily. At least once a day, a catheter should be cleaned with a solution of mild soap and water. The patient or patient’s caregiver should gently wash all around the area where the catheter goes in with the soapy washcloth. Females should wipe from front to back. Males should wipe from the tip of the penis downward. The patient or patient’s caregiver should never clean from the bottom of the catheter toward the body, as this can increase the risk of infection. Catheter tubing should be gently dried with a clean towel. Avoid the use of creams, powders or sprays near the catheter.
  • Drink fluids. Although there is some disagreement about the clinical validity of this measure, many nurses find that patients who are able to drink a sufficient quantity of fluids experience fewer problems with their catheters. Fluids can decrease the amount of sediment in the urine and “keep things moving” so that the catheter remans patent. Of course, patients on fluid-restricted diets (e.g. CHF patients) should not “force fluids” for the sake of their urinary catheter.
  • Correctly secure the catheter bag. Catheter bags should not be tugged, pulled or looped unnecessarily. When in bed, the bag should hang from the bed frame, not a moveable bed rail. Always keep the urine bag below the level of the bladder (this prevents backflow of urine, which can cause an infection), but off the floor.
  • Regularly empty drainage. This should be done at least once every 24 hours, or when the drainage back is half full, and at bedtime. Not emptying the bag can cause urine to back up through the tubing and into the bladder, which is dangerous and a potential source of infection.
  • Don’t change or irrigate the catheter unless necessary. Urinary catheters are a ‘closed’ system that are vulnerable to bacteria and infection when unnecessarily opened. Research demonstrates that it is better not to change a catheter unless necessary, and it is therefore advisable to not change on an arbitrary schedule (i.e. weekly or monthly). When properly cared for, indwelling catheters can be left in place without being changed. Valid clinical reasons for changing a catheter include obstruction, leakage unresolved by repositioning the catheter, or signs and symptoms of infection.
  • Know when and how to wear a catheter. Patients who are ambulatory should use leg straps to secure catheter tubing, not home made devices. Contrary to what some nurses may realize, patients may wear the catheter in the shower. Catheters should never be worn during sexual intercourse.

Removing a Catheter

  • Gather supplies and explain the procedure. You’ll need an empty 10 cc syringe with a Luer lock or taper, a towel, and a waste disposal container.
  • Get a towel and put it on the bed. The towel should be placed beneath the patient’s perineal area. This is to catch stray urine when the catheter tubing is removed.
  • Using the empty syringe, deflate the saline balloon. This is critical, because the inflated saline balloon is what keeps the catheter in place against the neck of the bladder. Once the saline has been removed, discard it and draw back a second time to ensure that all of the saline is out.
  • In one smooth, continuous motion, pull out the catheter. Don’t go too quickly, as this could cause urine to spray or splatter. Once you’ve got the catheter out, let it rest on the towel and wipe off the tip. Then, dispose of the catheter tubing and bag in a waste container.
  • Ensure the patient voids after the catheter has been removed. The patient should void 6 – 8 hours after the catheter has been removed; not voiding may be a sign of urinary retention. It may be helpful to encourage the patient to drink some water after catheter removal to produce urine and help them void. Some nursing ‘tricks’ for helping patients to void include blowing a straw in water, or putting a hand or finger in a cup of warm water.