Microwave sterilization: a method for home sterilization of urinary catheters

A standard microwave oven has been used to sterilize catheters used for intermittent self-catheterization. Catheters were incubated for 60 minutes in a suspension of microorganisms isolated from the urine of patients with urinary tract infections. Each catheter was removed from the suspension, placed in a paper bag and microwaved for 0 to 30 minutes. A control catheter was not microwaved. We tested 42 strains of microorganisms to determine the minimum microwaving time needed to sterilize the catheters. Representative urinary isolates of Escherichia coli, and Klebsiella, Proteus, Enterobacter, Pseudomonas, Staphylococcus, Streptococcus and Candida species were tested. Mean sterilization time for all strains was 13.0 minutes (standard deviation +/- 5.7 minutes), with a range of 4.0 to 28.6 minutes. Repeat sterilization in the microwave oven did not affect the integrity of the catheter. A water heat sink of constant volume was required. A home microwave oven may be used as a method to sterilize red rubber catheters for reuse. This technique makes aseptic intermittent self-catheterization a practical possibility.     

MICROWAVE STERILIZATION OF POLYETHYLENE CATHETERS FOR INTERMITTENT SELF-CATHETERIZATION

A standard household 650 W microwave oven was used to sterilize polyethylene catheters of the type used for intermittent self-catheterization. The Catheters were infected with Proteus sp. bacteria and microwaved at 650 W for periods of 2, 4, 6 and 8 minutes. The effect of microwaving was assessed by determining the resultant colony counts following catheter culture. It was determined that 6 minutes of microwaving were required to achieve sterility. It is suggested that use of a microwave oven is a reliable and cost-effective method of sterilizing polyethylene catheters for intermittent self-catheterization.     

Urinary catheter sterilization with microwave oven

Studies were conducted utilizing a home microwave oven to sterilize catheters commonly used for intermittent self-catherization. Red rubber urinary catheters were inoculated with common clinical uropathogens and were placed in sealed brown paper bags or Ziploc plastic freezer bags and microwaved at full power for various timed intervals. Differences were noted in killing time for some strains or species of bacteria. Twelve minutes at full power appeared to be sufficient time for complete sterilization of most catheters placed in plastic bags. Cold spots were noted in the oven; suggestions are made for placing the bags in certain areas to achieve complete sterilization of contaminated catheters. Repeat sterilization did not affect the integrity of catheters or the plastic bags. A water heat sink of constant volume was employed during the sterilization process. Six catheters could be sterilized at one time. This convenience allows patients reuse of catheters and provides less chances of self-inoculation due to reuse of contaminated catheters for intermittent self-catherization.     

Variability in catheter microwave sterilization techniques in a single clinic population

PURPOSE: We designed a survey to assess the microwave sterilization technique practiced by patients at our clinic who perform clean intermittent catheterization. MATERIALS AND METHODS: A 23-question survey addressing urinary catheter use and home sterilization techniques was mailed to 129 patients. A followup survey was mailed to 47 respondents who reported using a microwave oven to sterilize the catheters to assess the microwave technique further. RESULTS: Of the 129 initial surveys 84 (64%) were returned, while 40 (85%) of the 47 followup questionnaires on microwave sterilization were returned. All patients surveyed have used clean intermittent catheterization for at least 1 year and 75% have used it more than 5 years. Of the respondents 80% perform clean intermittent catheterization 4 to 5 times daily, although sterilization frequency varies from daily to less than once weekly. Of the respondents 71% reported no difficulty with microwave sterilization, although 31 (63%) reported a history of catheter melting during microwaving. Of the respondents 35% reported using a rotation table, all used a heat sink containing 1/2 to 4 cups of water, 39% used 500 to 1,000 W., 37% used greater than 1,000 W., 73% set the microwave for 6 minutes, others set it for 3 to 30 minutes and 98% used a power setting described as high, full, 10 or 100%. CONCLUSIONS: Significant variation exists in the cleaning and sterilizing techniques used by our patients, although they were given uniform written and verbal instructions. It is unclear from the data in the literature how this variation affects sterilization.     

A prospective randomized trial of the LoFric hydrophilic coated catheter versus conventional plastic catheter for clean intermittent catheterization

PURPOSE: We compared the incidence of hematuria, pyuria and clinical urinary tract infection in patients who performed intermittent self-catheterization using a hydrophilic coated LoFric (Astra Tech AB, M?lndal, Sweden) or standard plastic catheter. MATERIALS AND METHODS: A total of 62 male patients who performed intermittent self-catheterization to manage neurogenic bladder were randomized into 2 treatment groups at 3 American study sites. Outcome measures included urinary tract infection, microhematuria, pyuria and satisfaction rates. RESULTS: Of the 62 enrolled patients 49 completed the 12-month study. The withdrawal rate was not different in the 2 groups. At the end of the study there was statistically significantly less hematuria in the hydrophilic coated catheter group compared with controls. In addition, there was a significant decrease in the urinary tract infection rate from baseline in the hydrophilic coated catheter group but not in controls. CONCLUSIONS: Use of the hydrophilic coated catheter by patients on intermittent self-catheterization is associated with less hematuria and a significant decrease in the incidence of urinary tract infections. Therefore, it may be preferable for some patients, especially those with a history of difficult catheterization, urethral trauma or a high rate of urinary tract infection.     

The physical and antimicrobial effects of microwave heating and alcohol immersion on catheters that are reused for clean intermittent catheterisation

INTRODUCTION: Due to worldwide different health insurance policies, patients are often forced to reuse the catheters when performing Clean Intermittent Catheterisation (CIC). We have compared the physical qualities and the antimicrobial effects of two methods of reusing catheters: microwave heating and storage of the catheters in a 70% alcohol solution. The studies were performed during different lengths of time. MATERIALS AND METHODS: Three types of catheters (a standard polyvinylchloride catheter, a special polyvinylchloride catheter with flexible Ergothan tip and a prelubrified catheter), normally intended for single use, were submitted to the effect of a microwave oven (Multitech 215 High Grade and Whirlpool M220 750 W and 1000 W with rotating plate) or preservation in a 70% alcohol solution. To study the effects of microwave heating, a recipient of water was placed in the oven to spread the microwaves and to absorb the heat. The catheters were placed in a resealable plastic bag (Ziploc. To study the effects of preservation in a 70% alcohol solution, the catheters were immerged in the solution for different lengths of time. Thereafter were the physical qualities of the catheters evaluated by using the technique of Differential Scanning Calorimetry (DSC). The antimicrobial effect of the method was evaluated after grafting the catheters with pathogenic E. coli, P. aeruginosa or S. aureus strains. RESULTS: Microwave heating up to 12 minutes at 750 W caused only minimal changes in the physical qualities of all the catheters. However, there was only an antimicrobial effect of the microwave heating on E. coli and not on P. aeruginosa or S. aureus. If the catheter remained longer than 45 minutes in a 70% alcohol solution, the physical qualities of the catheter changed either minimal in the special polyvinylchloride catheter with flexible Ergothan top but changed significantly in the prelubrified catheter). However, already after 5 minutes of immersion in the 70% alcohol solution there was a complete antimicrobial effect on E. coli, P. aeruginosa and S. aureus in all catheters. CONCLUSIONS: It should be recommended to patients on CIC to use a sterile packed and not previously used catheter. In this study we have shown that immersing the catheters in a 70% alcohol solution during 5 minutes can effectively disinfect the catheter without jeopardising the physical qualities. Thereafter, the catheters could be placed in a resealable (e.g. Ziploc bag without being rinsed under water, in order that the few drops of alcohol cause alcohol vapours within the closed plastic bag and maintain the antimicrobial effect.     

Recurrent urethral stricture disease managed by clean intermittent self-catheterization

We studied 41 patients with urethral stricture who had failed at least 1 operation, and were being maintained with filiform and follower dilation every 6 to 12 weeks. The patients were instructed in clean intermittent self-catheterization with a 16F red rubber catheter, which was performed every 1 to 30 days. Followup from 9 to 36 months revealed excellent compliance and average peak uroflow rates increased from 5.5 cc per second before dilation to 17.1 cc per second at the last followup visit. Clean intermittent self-catheterization is a simple method to maintain a patent urethra and obviates the need for further operations or painful dilations.     

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

STUDY DESIGN: Prospective study of intermittent self-catheterization (CIC) with change from conventional catheter to low-friction Urocath-Gel catheter. OBJECTIVES: To evaluate if such catheters are well accepted and to evaluate their practical use. METHODS: Thirty-nine male patients, between 19 and 74 years old, performing clean intermittent self-catheterization with conventional catheters for a neuropathic bladder for many years were included in this study after written informed consent. Exclusion criteria were clinical urinary tract infection, acute infection of urethra, prostate or epididymis, untreated urethral strictures and false passages or severe urethral bleeding occurring within the last month. During 1 month they changed to the use of the Urocath-Gel catheter. Complications were noted. Satisfaction was evaluated by a visual analogue scale and by questioning. RESULTS: Four patients did not complete the study, two for side effects, two for difficulties with the catheterization technique. Time needed for CIC was not different with both techniques. Difficult introduction or difficult retreat of the catheter were not different in frequency. Impossibility to introduce the catheter was less frequent. Urethritis and urethral bleeding were less frequent than during the use of conventional catheters. Satisfaction was better with the low friction catheters. Negative satisfaction was mainly related to the availability and the use of water to lubricate the catheter, difficulty of manipulation and fear for cost. CONCLUSION: The hydrophilic catheter Urocath-Gel proved as easy to use as conventional catheters but was better tolerated. Satisfaction was better especially in patients who experienced problems with conventional catheters. Some patients were unsatisfied for reasons of practical use or for economical reasons.     

Differenzialindikationen für verschiedene Harnableitungsformen

When urinary diversion is indicated, patient information concerning the advantages and disadvantages of different types of urinary diversion and their choices is of utmost importance for the functional outcome and patient satisfaction. There is a variety of choices for incontinent urinary diversion (ureterocutaneostomy, ileal conduit, colonic conduit) and continent urinary diversion (continent anal urinary diversion, continent cutaneous urinary diversion and urethral bladder substitution). In the individual case, the choices may be limited by patient criteria and/or medical criteria. Important patient criteria are preference, age and comorbidity, BMI, motivation, underlying disease and indication for cystectomy. Medical criteria which possibly limit choices of type of urinary diversion are kidney function/upper urinary tract status and limitations concerning the gastrointestinal tract, concerning urethra/sphincter as well as the ability and motivation to perform intermittent self-catheterization. Preoperative information may use simulation of certain postoperative scenarios (urethral self-catheterization, fixation of water-filled conduit bags, holding test for anal liquids) to allow the individual patient to choose the optimal type of urinary diversion for his/her given situation from the mosaic of choices and possible individual limitations.     

Long-term clean intermittent self-catheterization in renal transplant recipients

Eight renal transplant recipients with neurogenic bladders or lower urinary tract dysfunction were managed with clean intermittent self-catheterization after transplantation instead of urinary diversion. A total of 85 treatment months was reviewed. Of the patients 5 continue to do well after 10 to 17 months of intermittent catheterization and 3 suffered immunological graft failures. In selected renal transplant recipients with lower urinary tract dysfunction clean intermittent catheterization is a reasonable alternative to urinary diversion.     

A comparison of prelubricated hydrophilic and non-hydrophilic polyvinyl chloride catheters for urethral catheterization.

OBJECTIVE: To evaluate whether patients performing clean intermittent self-catheterization (CISC) for a short period preferred a prelubricated, hydrophilic, disposable polyvinyl chloride (PVC) catheter or a non-hydrophilic PVC catheter which could be used several times and that had to be lubricated by the patient. PATIENTS AND METHODS: In a prospective cross-over study, 32 patients used each type of catheter for 3 weeks. After each 3-week period, the patients completed a questionnaire to assess comfort and preference, and urine specimens were obtained for culture. RESULTS: There was no significant difference between the groups in the frequency of CISC, discomfort when used, opinion on handling the catheters, preference toward one of the catheters, or of infection. CONCLUSION: Non-hydrophilic PVC catheters may be used safely and with no discomfort to the patient. In addition it may be possible for the healthcare system to save money, as the non-hydrophilic PVC catheters are much cheaper.     

微波联合氯己定用于金属器械快速灭菌的实验研究

目的寻求金属器械快速灭菌的方法 ,满足手术过程中急需器械的灭菌需求。方法将 336件金属手术器械人工染菌后放入微波炉专用塑料盒中 (7件 /盒 ) ,分别加入 0 .5 %氯己定溶液、蒸馏水各 30 0ml加盖 ,置入家用微波炉(2盒 /次 ,14件 ) ,使用高火档 (输出功率 6 5 0W ) ,3、5min分别消毒 2 4次 ,消毒后分别按常规采样做无菌检测 ,观察灭菌效果。结果家用微波炉加蒸馏水作用 3min灭菌合格率为 88.0 9% ,5min灭菌合格率为 95 .2 4 % ;加 0 .5 %氯己定溶液消毒 3min灭菌合格率为 93.4 5 % ,5min灭菌合格率达 10 0 .0 0 %。结论金属器械经家用微波炉 (输出功率为 6 5 0W )与 0 .5 %氯己定溶液协同作用 5min ,即可完全灭菌 ,解决手术过程中急用金属器械的消毒灭菌问题。     

Suprapubic endoscopic vesical neck suspension (Stamey procedure) for control of urinary incontinence in a woman following cauda equina injury

Suprapubic endoscopic suspension of the vesical neck is a popular and effective procedure for the treatment of stress urinary incontinence in women. A woman who suffered a traumatic cauda equina injury had areflexic detrusor dysfunction with normal intravesical filling pressure. The patient had moderate proximal urethral dysfunction resulting in incontinence despite an adequate intermittent self-catheterization regimen and treatment with an alpha-sympathomimetic drug. Following suprapubic endoscopic vesical neck suspension she has remained totally continent on intermittent self-catheterization.     

Urinary undiversion by conversion of the incontinent ileovesicostomy to augmentation ileocystoplasty in spinal cord injured patients

Context: Spinal cord injury (SCI) patients with neurogenic bladder and the inability to self-catheterize may require incontinent diversion to provide low-pressure drainage while avoiding the use of indwelling catheters. We demonstrate that in patients with significant functional improvement, the ileovesicostomy can be a reversible form of diversion, with simultaneous bladder augmentation using the same segment of ileum utilized for the ileovesicostomy. Multidisciplinary management should be utilized to assure mastery of intermittent catheterization before urinary undiversion. This technique allows for transition to a regimen of intermittent self-catheterization with excellent functional and urodynamic outcomes.Design: Case Series.Setting: Tertiary care hospital, Philadelphia, Pennsylvania.Participants: Three individuals with an SCI.Interventions: Conversion of bladder management from an incontinent ileovesicostomy to an augmentation ileocystoplasty, with intermittent catheterization.Outcome Measures: Ability to regain urinary continence with preservation of renal function as determined by serum creatinine and renal ultrasound.Results: Three SCI patients who had an incontinent ileovesicostomy developed sufficient functional improvement to intermittently self-catheterize reliably and underwent conversion of ileovesicostomy to ileocystoplasty. For each, the ileovesicostomy channel was taken down and detubularized, then used to create an ileal patch for augmentation ileocystoplasty. Intermittent catheterization was then used for periodic bladder drainage. All achieved large capacity, low-pressure bladders with complete continence and stable creatinine.Conclusion: In motivated SCI patients, it is possible to regain continence by converting the ileovesicostomy into augmentation ileocystoplasty, avoiding the disadvantages of a urostomy. A multidisciplinary collaborative approach facilitates the optimal rehabilitation of SCI individuals.     

A study on non-sterile intermittent self-catheterization for voiding dysfunction following radical uterine or rectal carcinoma surgery

To determine the effectiveness of non-sterile intermittent self-catheterization, a study was made of 35 patients who had radical surgery of the carcinoma of the uterus or rectum between January, 1978 and October, 1982. These cases were divided into 2 groups; (1) early instituted group of 27 patients who used self-catheterization within 3 months following surgical intervention; (2) late instituted group of 8 patients who received drug treatment for more than 3 months after surgical treatments and then used self-catheterization. After the introduction of self-catheterization, urinary tract infection was evaluated on the basis of the incidence of pyuria defined as more than 5 white blood cells per high magnification field. In 16 of the 35 patients, the incidence of pyuria ranged from 0 to 20 per cent. Regarding prognostic results in the first group the application of self-catheterization, 6 patients had a residual urine ratio ranging from 0 to 20 per cent and were able to void at will. Uroflometry was performed in 9 patients in the first group. In 8 of these patients, UP max values increased 3 months after self-catheterization as compared with those before self-catheterization although their values were still lower than normal. Non-sterile intermittent self-catheterization can shorten the stay in hospital and enable the patient to live a catheter-free life.     

Clean intermittent self-catheterization in the elderly

There has been some doubt as to whether or not the elderly patient can successfully master and comply with clean intermittent self-catheterization in the treatment of their bladder dysfunctions. We recently reviewed our experience with intermittent self-catheterization in patients sixty years of age and older to determine whether or not this was an acceptable alternative to other methods of urinary drainage. Our retrospective analysis of 65 patients between the ages of sixty and eighty years revealed that the elderly patient had little difficulty mastering the technique of intermittent self-catheterization. Complications were minimal and in general correctable. The catheterization program was successful in 94 per cent of the patients in our series.     

Treatment of immobilization hypercalciuria using weekly alendronate in two quadriplegic patients

Metabolic and urinary problems encountered in spinal cord injury patients are multifaced. We report two patients with high-level spinal cord injuries who have developed hypercalciuria after admission to the rehabilitation unit. To establish a clean intermittent self-catheterization programme, the hypercalciuria was treated successfully with alendronate. Twenty-four-hour urinary calcium excretion decreased significantly after medical treatment for hypercalciuria. Since high-level quadriplegic patients may not be mobilized in the acute phase of the rehabilitation, use of alendronate for preventing hypercalciuria and maintaining a successful clean intermittent self-catheterization programme can be considered as a supportive/complementary measure.     

Bladder management and risk of bladder stone formation in spinal cord injured patients

PURPOSE: We determined by statistical analysis whether method of management is associated with risk of bladder stone formation in spinal cord injured patients. MATERIALS AND METHODS: A retrospective cohort study was performed of 457 patients admitted to Stoke Mandeville Hospital Spinal Injuries Center between 1985 and 1990 with more than 6 months of followup. Analysis included Cox regression and Poisson regression. RESULTS: Relative to those patients treated with intermittent self-catheterization, the hazard ratio was 10.5 (p <0.0005, 95% confidence interval 4.0-27.5) for patients with suprapubic catheters and it was 12.8 (p <0.0005, 95% confidence interval 5.1-31.9) for those with indwelling urethral catheters. The absolute annual risk of stone formation in patients with a catheter was 4% compared with 0.2% for those on intermittent self-catheterization. However, having formed a stone, the risk of forming a subsequent stone quadrupled to 16% per year. Bladder stones were no more likely to form in patients with suprapubic catheters compared to those with indwelling urethral catheters (hazard ratio 1.2, p = 0.6). CONCLUSIONS: In spinal cord injured patients long-term catheterization is associated with a substantial increased risk of bladder stone formation. This increased risk occurs independently of age, sex and injury level. Degree of injury (complete or incomplete) was considered in the model. Catheter type (suprapubic or urethral) did not change this risk significantly if at all.     

Augmentation enterocystoplasty for the management of voiding dysfunction in spinal cord injury patients

A total of 12 spinal cord injury adults underwent augmentation enterocystoplasty for treatment of a high pressure neurogenic bladder. These patients suffered from urinary incontinence, recurrent urinary tract infection, upper tract deterioration and severe autonomic dysreflexia. A sigmoid colon segment fashioned into a cup-patch was used in 11 patients and detubularized cecum was used in 1. The artificial urinary sphincter was implanted in 3 patients at augmentation enterocystoplasty and in 1 after enterocystoplasty. After a mean followup of 15 months all patients were continent on clean intermittent self-catheterization, the upper tract had remained stable or had improved and the symptoms of autonomic dysreflexia had disappeared. A third of the patients are on maintenance antibiotic therapy to control bacteriuria.     

A novel intraurethral prostatic bridge catheter for prevention of temporary prostatic obstruction following high energy transurethral microwave thermotherapy in patients with benign prostatic hyperplasia

PURPOSE: We evaluate the efficacy and safety of a novel intraurethral prostatic bridge catheter in preventing temporary prostatic obstruction following targeted high energy transurethral microwave thermotherapy in patients with benign prostatic hyperplasia. MATERIALS AND METHODS: A total of 54 patients with benign prostatic hyperplasia underwent high energy transurethral microwave therapy under topical urethral anesthesia followed by placement of a prostatic bridge catheter, which remained indwelling as long as 1 month (prostatic bridge catheter group). Patient evaluation included determination of peak urinary flow rate, International Prostate Symptom Score (I-PSS) and quality of life score at baseline, immediately following transurethral microwave therapy and prostatic bridge catheter placement, and periodically thereafter for 1 month. Results were retrospectively compared with those of 51 patients who underwent transurethral microwave therapy followed by standard temporary urinary catheterization, typically for 24 hours (standard catheterization group). RESULTS. Immediately following transurethral microwave therapy and prostatic bridge catheter placement significant improvements (p <0.0005) were observed in mean peak flow rate, I-PSS and quality of life score of 59.3, 33.5 and 23.6%, respectively, compared with baseline values. Further improvements were noted up to 1 month, at which time mean peak flow rate, I-PSS and quality of life score had improved 79.0, 54.9 and 56.5%, respectively, versus baseline (p <0.0005). In a retrospective comparison at baseline and 14 days between the prostatic bridge catheter group and standard catheterization group mean baseline peak flow rate, I-PSS and quality of life score were similar. However, at the 14-day followup evaluation in the prostatic bridge catheter group mean peak flow rate was 101.8% higher, and I-PSS and quality of life score were 47.9 and 51.1% lower, respectively, than the corresponding values in the standard catheterization group (p <0.0005). The prostatic bridge catheter was well tolerated and remained indwelling throughout the entire 1-month followup in 48 of 54 patients (88.9%). Early prostatic bridge catheter removal was required in 3 patients (5.6%) due to urinary retention and in 3 (5.6%) due to catheter migration. CONCLUSIONS. Prostatic bridge catheter placement provides an effective and well tolerated option for preventing prostatic obstruction in the acute period after transurethral microwave therapy. This approach avoids the inconvenience and infection risk of standard indwelling catheters or intermittent self-catheterization. Prostatic bridge catheter insertion and removal are rapid, facile, nontraumatic procedures. Prostatic bridge catheter may potentially be used in an array of minimally invasive procedures involving thermal treatment of the prostate gland.