The Royal Marsden Hospital Manual of Clinical Nursing Procedures - Lisa Dougherty [177]
Balloon (Foley) three-way irrigation catheter: three channels, one for urine, one for irrigation fluid; one for balloon inflation Latex, PTFE-coated latex, silicone, plastic To provide continuous irrigation (e.g. after prostatectomy). Potential for infection is reduced by minimizing need to break the closed drainage system (Mulhall et al. 1993)
Non-balloon (Nelaton) or Scotts, or intermittent catheter (one channel only) PVC and other plastics To empty bladder or continent urinary reservoir intermittently; to instil solutions into bladder
PTFE, polytetrafluoroethylene; PVC, polyvinylchloride.
Figure 6.4 Catheter types.
Balloon size
In the 1920s, Fredrick Foley designed a catheter with an inflatable balloon to keep it positioned inside the bladder. Balloon sizes vary from 2.5 mL for children to 30 mL. The latter is used to aid haemostasis after prostatic surgery. Large balloon catheters (30 mL) weigh approximately 48 g, causing pressure on the bladder neck and pelvic floor and potential damage to these structures (Kristiansen et al. 1983, Pomfret 2003, Robinson 2001). These catheters are associated with leakage of urine, pain and bladder spasm as they can cause irritation to the bladder mucosa and trigone (Robinson 2001, Stewart 1998). Large balloons are inclined to sit higher in the bladder, allowing a residual pool of urine to collect below the balloon and thus providing a reservoir for infection (Getliffe 1996a, Pomfret 2003).
Consequently, a 5–10 mL balloon is recommended for adults and a 3–5 mL balloon for children.
Care should be taken to use the correct amount of water to fill the balloon because too much or too little may cause distortion of the catheter tip. This may result in irritation and trauma to the bladder wall, consequently causing pain, spasm, bypassing and haematuria. If underinflated, one or more of the drainage eyes may become occluded or the catheter may become dislodged. Overinflation risks rupturing the balloon and leaving fragments of it inside the bladder (Pomfret 2003, Robinson 2001). Catheter balloons should only be inflated once; deflation/reinflation or topping up are not recommended by the manufacturers as distortion of the balloon may occur (Nazarko 2009, Robinson 2004).
Catheter balloons ought to be filled only with sterile water (Hart 2008). Tap water and 0.9% sodium chloride should not be used as salt crystals and debris may block the inflation channel, causing difficulties with deflation (Head 2006). Any micro-organisms which may be present in tap water can pass through the balloon into the bladder (Falkiner 1993, Stewart 1998).
Catheter size
Urethral catheters are measured in charrières (ch). The charrière is the outer circumference of the catheter in millimetres and is equivalent to three times the diameter. Thus a 12 ch catheter has a diameter of 4 mm.
Potential side-effects of large-gauge catheters include:
pain and discomfort
pressure ulcers, which may lead to stricture formation
blockage of paraurethral ducts
abscess formation (Blandy and Moors 1989, Crow et al. 1986, Edwards et al. 1983, Roe and Brocklehurst 1987, Winn 1998)
bypassing – urethral leakage.
The most important guiding principle is to choose the smallest size of catheter necessary to maintain adequate drainage (McGill 1982, Robinson 2006). If the urine to be drained is likely to be clear, a 12 ch catheter should be considered. Larger gauge catheters may be necessary if debris or clots are present in the urine (Pomfret 1996, Winn 1998).
Length of catheter
There are three lengths of catheter currently available:
female length: 23–26 cm
paediatric: 30 cm
standard length: 40–44 cm.
The shorter female length catheter is often more discreet and less likely to cause trauma or infections because movement in and out of the urethra is reduced. Infection may also be caused by the longer catheter looping or kinking (Pomfret 2003, Robinson 2001). In obese women or those in wheelchairs, however, the inflation valve of the shorter catheter