Urinary catheter balloons should only be filled with water: testing the myth

OBJECTIVE

To test the hypothesis that urinary catheter balloons filled with sterile water, saline or glycine have equivalent rates of failure to deflate.

MATERIALS AND METHODS

This was an in vitro equivalence study designed to test whether saline or glycine are neither substantially worse nor substantially better than water in terms of balloon‐deflation failure rates. Glycine was chosen as the third arm, as it is readily available during endoscopic procedures and would be useful to use in such situations. We hypothesised that balloon‐deflation failure rates using saline or glycine were no worse than water by 10%. We calculated the sample size for equivalence testing; 600 catheters were randomized by computer‐generated random numbers to receive 10 mL of water, saline or glycine, and then immersed in a heated artificial urine solution for 6 weeks. The catheter balloons were then deflated, noting any failures to deflate and recording the deflation volumes.

RESULTS

There was no failure to deflate in all 600 catheters. The median deflation volume for water, saline and glycine was 9.0, 9.2 and 9.1 mL, respectively (P < 0.001 Kruskal–Wallis test). Post‐hoc pair‐wise comparisons showed that the deflation volume difference between water and saline was significant (P < 0.001), as was that between water and glycine (P < 0.001). The practical implication of this difference is not apparent from this study.

CONCLUSIONS

The use of saline or glycine in catheter balloons has an equivalent deflation failure rate to using water, which in this study was zero.     

Urinary retention due to catheter occlusion by worms

Herein we report a very rare case involving acute occlusion of a Foley catheter by worms. The treatment consisted of removal of the occluded catheter followed by bladder washing with a Betadine solution mixed with normal saline and introduction of a new catheter.     

Central venous catheter stiffness and its relation to vascular perforation

Delayed central venous perforation is an uncommon but serious complication of central venous catheter insertion. An increase in catheter stiffness may have been responsible for our association of venous perforation with use of a guidewire insertion technique. A bench model was used to investigate the stiffness characteristics of thirty-four different types of catheters. The initial stiffness is poorly described by material or catheter gauge. A large range of values is seen between apparently similar catheters--the 16 gauge polyethylene catheter associated with two perforations at our institution had an initial stiffness value 7.5 Nm2 X 10(-5) at 37 degrees C in comparison with our previous standard--the 16 gauge Deseret Intracath with an initial stiffness of 2 Nm2 X 10(-5). Multilumen catheters had a similar range of stiffness to single lumen catheters, while paediatric catheters in general were less stiff. Dialysis catheters were up to five times as stiff as the stiffest central venous catheter. Stiffness decayed at a rate and to an extent which differed from catheter to catheter. Absorption of water by the catheter appears to be one factor involved in stress relaxation.     

Urinary retention in early urinary catheter removal after colorectal surgery

Background

High urinary infection (UTI) rate (12%) for our rectal surgery prompted practice change to early catheter removal (postoperative day 2) and prophylactic tamsulosin. Here we report urinary retention (UR) and UTI after this change.

Urinary angiotensinogen levels in relation to renal involvement of Henoch-Schonlein purpura in children

Aim: To investigate whether urinary angiotensinogen (UAGT) levels are correlated with renal involvement of Henoch‐Schonlein purpura (HSP) in children, and to explore whether UAGT has any relation to the severity of HSP. Methods: The study sample consisted of 107 patients (50 boys and 57 girls, 6.68 ± 2.41 years) with clinical diagnosis of HSP. A 24 h urine sample was collected before treatment. UAGT levels were measured in patients with HSP in the acute and convalescent phases by enzyme linked immunosorbent assay. Results: Urinary angiotensinogen/urinary concentration of creatinine levels were significantly higher in proteinuric HSP in the acute phase and the convalescent phase (32.02 ± 3.95 and 25.31 ± 4.11 µg/g) compared with those with HSP without renal involvement (17.26 ± 2.60 and 15.14 ± 3.81 µg/g) and those with hematuric HSP (19.70 ± 2.21 and 17.28 ± 3.62 µg/g) (P < 0.0001 and P < 0.01, respectively). Using matched urine samples from the same patients, UAGT/urinary concentration of creatinine (UCr) levels of proteinuric HSP patients were significantly lower in the convalescent phase (25.31 ± 4.11 µg/g, P < 0.01) than in the acute phase (32.02 ± 3.95 µg/g). UAGT/UCr levels showed positive correlation with 24 h urine protein or serum creatinine in both hematuric HSP and proteinuric HSP groups during the acute phase (P < 0.05). Conclusions: Urinary angiotensinogen levels were remarkably high in the acute phase in the patients with proteinuric HSP, suggesting increased UAGT may indicate a series of functional changes in the kidney and it may be used as a potential biomarker of severity of HSP to monitor the progression of HSP with renal involvement.     

Urinary tissue factor activity in colorectal disease

Procoagulant activity (PCA) in normal urine has been recognized for over 50 years. Although tissue factor (TF) is produced by certain tumours, and is increased in both tumour-associated macrophages and blood monocytes, the possibility that it might also be increased in urine has not been studied in patients with cancer. We have measured urinary PCA in hospital controls without inflammatory or neoplastic disease (n = 79), in patients with rheumatoid arthritis (n = 8), inflammatory bowel disease (n = 19), colorectal cancer (n = 70) and in patients undergoing colonoscopy (n = 50). Urinary PCA was higher (P less than 0.001) in patients with colorectal cancer and inflammatory bowel disease than controls or patients with rheumatoid arthritis. Fourteen (88 per cent) out of 16 colonoscopy patients subsequently found to have carcinoma or inflammatory bowel disease had levels above the control upper quartile, compared with 8 (24 per cent) out of 34 with normal colonoscopy (P less than 0.001). TF inhibitors confirmed the nature of the PCA and Western blotting studies indicated a urinary TF molecular weight of approximately 38,000. These studies provide further evidence of abnormal haemostasis in malignancy and suggest that determination of urinary TF may provide a useful screening test in patients undergoing colonoscopy.     

Rat peritoneal implantation test. A new method for tissue toxicity testing of urinary catheters

Severe urethral inflammatory reactions followed by strictures have been reported after short-term catheterisation with latex catheters since 1982. In this study a new method for assessing tissue toxicity is presented. It is based on the degree of inhibition of rat peritoneal foreign body reaction. Because the results are easier to interpret and more quantitative than those of the rabbit muscle implantation test, the rat peritoneal implantation test is recommended as a standard in vivo toxicity test.     

Urinary and renal tissue kallikrein in the streptozocin-diabetic rat

The renal kallikrein-kinin system is thought to participate in blood pressure regulation and displays abnormalities in human hypertension, as well as in many animal models of hypertension. Urinary excretion and tissue levels of renal kallikrein were measured in streptozocin (STZ)-diabetic rats in relation to blood pressure, glycemia, and insulin treatment. In study 1, STZ-diabetic rats with marked hyperglycemia showed reduced kallikrein-like esterase excretion, compared with control rats, when first measured after 7 days of diabetes (9.9 +/- 2.5 versus 17.5 +/- 2.4 EU/24 h, P less than 0.05). This difference increased with time and, after 210 days, urinary esterase excretion in diabetic and control rats was 6.7 +/- 2.1 and 39.0 +/- 6.0 EU/24 h, respectively (P less than 0.001). Urine kallikrein, measured by radioimmunoassay, was similarly reduced in diabetic rats (40.4 +/- 8.0 versus 88.0 +/- 6.5 micrograms/24 h, at 30 days, P less than 0.001). At 120 days, systolic blood pressures were elevated in diabetic rats (P less than 0.05), and at 180 days over 60% of the diabetic rats had pressures above the highest pressures of control rats. In study 2, STZ-diabetic rats were treated with insulin for 2 wk (2 U NPH at 0800 h, or 2 U NPH at 0800 and 1600 h). In the single-dose group, with hyperglycemia similar to that of diabetic rats in study 1, kallikrein excretion was reduced as early as day 2, compared with nondiabetic rats (56.0 +/- 6.1 versus 109 +/- 9.4 micrograms/24 h, respectively, P less than 0.001).(ABSTRACT TRUNCATED AT 250 WORDS)     

Sex steroids in relation to cardiac structure and function in men

The prevalence of testosterone substitution as well as of androgen deprivation therapy in men is increasing. This review aims to summarise available knowledge of the effects of sex steroids on cardiac structure and function in men. MEDLINE was searched through PubMed. Original studies, systematic reviews and meta‐analyses, and relevant citations were screened. A short‐term hormonal intervention study in healthy young men with respect to echocardiographic parameters of structure and function was performed. Preclinical research provides sufficient evidence for the heart as a substrate for sex hormones. In animals, administration of oestradiol appears to have beneficial effects on cardiac structure and function, whereas administration of testosterone to noncastrated animals adversely affects cardiac function. However, the effects of sex steroids on cardiac function and structure appear more heterogeneous in human observational studies while comparative, prospective studies in humans are lacking. It is concluded that although effects of testosterone substitution as well as of androgen deprivation on cardiac structure and function can be expected based on pre‐clinical research, there exists an important knowledge gap of the effects of hormonal intervention in men. As such, there is a need to address this question in future prospective intervention trials.     

Urinary catheter 'deflation cuff' formation: clinical audit and quantitative in vitro analysis

OBJECTIVE: To investigate reports from district nursing staff of difficulty in removing long-term urinary catheters (LTCs) because of the formation of a 'cuff' on deflating the self-retaining balloon. PATIENTS AND METHODS: Problems experienced by district nurses when removing urethral and suprapubic LTCs were audited, noting the type of problem, the catheter and any action taken. Quantitative in vitro studies were conducted on the deflated self-retaining balloons after incubating a similar range of catheters in saline at 37 degrees C for 6 weeks, using suprapubic profilometry to assess the resistance to withdrawal (retention force). RESULTS: Questionnaires were returned on 154 patients with LTCs; 56% had urethral and 44% suprapubic catheters. The catheters were hydrogel-coated (83%), all-silicone (13%) and PTFE-coated (3%). Twenty-two (14%) of the sample reported problems with catheter removal in the previous year, including 15 (68%) with all-silicone catheters and 15 (68%) with suprapubic catheters; cuff formation was noted in 60%. In the laboratory, 10 of the balloons formed a 'cuff' on deflation, but there was great variability in the effect this had on the retention force, with values of 0.5-3 N for different catheters. CONCLUSIONS: Most problems with catheter removal involved all-silicone and suprapubic catheters. Suprapubic profilometry confirmed increased resistance to withdrawal by formation of a 'cuff' on deflation of the balloon of all-silicone catheters. These results suggest that the first choice of catheter material for long-term urethral and suprapubic use should be hydrogel-coated latex.     

Dupuytren's contracture. Fine structure in relation to aetiology

The fine structure of palmar fascia from patients with Dupuytren's contracture (DC) was compared with that from patients with carpal tunnel syndrome (CTS). In contrast to previous assumptions, the ultrastructure of fibroblasts both in vivo and in vitro from DC and CTS appeared identical, indicating that myofibroblasts are not specific to DC. The major differences between DC and CTS were: 1) a sixfold and fortyfold increase in fibroblast density in cord and nodular areas of DC compared with CTS; 2) a more disorganised pattern of collagen fibrils in DC; and 3) markedly narrowed microvessels surrounded by thickened, laminated basal laminae and proliferating fibroblasts in DC compared with CTS. To account for these morphological changes a hypothesis is presented which proposes that oxygen-free radicals cause pericytic necrosis and fibroblastic proliferation. This hypothesis provides a potential avenue for therapy of DC and other fibrotic conditions.