The importance of osmolality in hydrophilic urethral catheters: a crossover study

Abstract

The longterm use of clean intermittent self catheterisation as an option for bladder management in the care of spinal cord injury patients has shown the possible risk of urethral trauma and chronic infections being developed over time. The basic properties of the catheters being used need to be evaluated. In this crossover study of 14 male spinal cord injury patients, two commercial hydrophilic catheters were compared, as to the maximum friction force during the removal of the catheters after bladder emptying. The friction force, measured by a dynamometer twice daily, showed signi®cant lower values for LoFric (0.87/0.84 N) than for EsiCath/Conveen (1.38/1.27 N). Sticking to the urethral epithelium was reported three times (two patients) with the LoFric catheter, and 42 times (nine patients) with the EasiCath catheter. Osmolality of the outer layer of the catheters was measured using a freezing-point reduction technique. The greater than 10 times higher osmolality (*900 mOsm/kg) of the Lofric catheter may explain the results.Keywords: spinal cord injuries; urethral catheterisation; osmolality of catheters IntroductionIntermittent catheterisation (IC) and clean intermittent catheterisation (CIC) are the results of innovative ideas which have been most prevalent in the medical health and psycho-social life of spinal injury patients during the past 40 years. 1 ± 5 People's doubts surrounding new paradigms should be seen more as a result of tradition than a lack of technology for running conclusive, comparative studies. Nowadays, the technology exists but a decisive routine for starting randomised clinical trials is lacking in more or less the entire spinal injury area. Within the ®eld of neurology, detailed long-term follow-ups of the Lapides method have stated that urethral complications and chronic infections are dependent on the length of the regimen, 6 ± 9 while the hydrophilic CIC catheters could reduce these complications. 10,11 The time seems right for a comparative prospective clinical trial. 9 The hydrophilic catheter which has so far been tested (LoFric) seems to cause less short-term strains 12 and long-term trauma 10,11 and should logically reduce the risk of chronic prostatitis and epididymitis. 9,10 Positive results of self-catheterisaton have also been seen in stricture treatment following urethrotomy 13 including the low-friction variation. 14 Conclusive support for this requires prospective and su ciently large-scale studies over many years, where the optimal properties for the atraumatic performance of the catheters involved are tested and compared.This preparatory clinical study in a crossover design compares the friction during catheter removal between two commercial hydrophilic catheters as part of the spinal injury patient's usual bladder regimen during the post-injury phase.

Complications of intermittent catheterization: their prevention and treatment

“…The degree of urethral in¯ammation by urethral cytology proved to be less in patients using hydrophilic catheters compared to PVC catheters. 75 No extra strictures occured in patients on IC with hydrophilic catheters after a mean follow-up of 7 years in a study of Waller et al 76 Such data are suggestive that there is an advantage in using hydrophilic catheters to prevent stricture formation in the long-term but comparative studies have not been published. Urethral trauma with false passages can, in neurogenic patients on CIC, successfully be treated with 5 days antibiotics and 6 weeks indwelling catheter.…”

Evaluation of the use of Urocath-Gel® catheters for intermittent self-catheterization by male patients using conventional catheters for a long time

“…15 It can also be caused by spasticity of the urethral sphincter and the pelvic¯oor around the catheter.…”

Intermittent catheterization with hydrophilic catheters as a treatment of chronic neurogenic urinary retention

“…19 These data on relative discomfort in healthy volunteers are particularly important as patients with neurogenic bladder often have reduced (or no) urethral sensation as a result of their neurological dysfunction, making such observations difficult in this population. An earlier study also reported on withdrawal friction force with hydrophilic catheters, 27 but was potentially confounded by a lack of blinding and the use of hand-held measurement methodology.…”