Internal and External Urinary Catheters: A Primer for Clinical Practice
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Woodbury et al42 noted the mean frequency of self-reported UTIs in persons with SCI was 2.6 occurrences in the 12-month reporting period and that individuals who catheterized only once per day had the highest number of infections (38% of patients had five or more UTIs per year), most likely related to higher volumes of urine in the bladder at time of catheterization. Women had a higher incidence of UTIs than men and patients who self-catheterized had fewer UTIs. Interestingly, most UTIs (78%) were managed by family physicians — only 13% were managed by urologists. This is usually not the case in the US where SCI patients are usually managed by urologists. 2 Woodbury’s42 study also showed that the use of prophylactic agents such as cranberry juice, vitamin C supplements, and increased fluid intake decreased UTI rate in this community-based SCI population.
Complications. Bacteriuria occurs in 50% of IC users but rarely leads to symptomatic UTIs and should not be treated with antibiotics.15 Symptomatic UTIs occur in 10% to 15% of patients using IC and, as mentioned, are more prevalent in those who have higher residual urine volumes at the time of catheterization. 2 The catheterization schedule should be based on urine volume. As a general rule, bladder volume should not exceed 400 mL. Chronic pyelonephritis rarely develops in patients performing IC so prophylactic antibiotics should not be routinely prescribed. 44 Urethral damage can occur in male patients performing IC and urethral complications are similar to what is seen in patients with a long-term IUC but do not occur as frequently.
Another urethral complication is the formation of a stricture, indicated when the catheter does not pass easily. Creation of a false passage can occur, primarily in men with persisting urethral strictures, and may occur at the site of the external sphincter just distal to the prostate. Bladder stones may occur in patients who perform IC over the long term. Stones have been shown to grow around introduced pubic hairs. 2
Types of catheters used for IC. The size and tips of catheters used intermittently are similar to those described for IUCs. Catheters range from 6 Fr to 12 Fr for children and from 14 Fr to 22 Fr for adults. The funnel end of the catheter is usually color-coded to identify French size easily. Intermittent catheters have different lengths. Men use catheters with lengths of about 12 inches (about 40 cm) and women and children ideally should use shorter lengths of 6 to 12 inches (20 cm to 40 cm) because of their shorter urethral length. 10 This allows more efficient drainage by reducing the risk of looping, kinking, and upward gradient drainage of the tube.
The difference between catheters inserted intermittently and those that are indwelling involves surface properties. The type of surface may influence associated problems of IC, such as urethral complications and UTIs, as well as user satisfaction and preference. 2 Catheters used for IC can be made of rubber that contains latex (called a “red rubber catheter”). They are more flexible and often are recommended for patients who are performing IC on a short-term basis (eg, following stricture dilation). Polyvinyl catheters (PVC), the most commonly used catheter for IC, are firmer and feature a larger internal diameter. Both of these catheters require lubrication for insertion in both men and women. An increasingly popular type of catheters is hydrophilic-coated45,46 (see Figure 3 and Figure 10). These catheters have a layer of polymer coating that is bound to the catheter surface.