Microwave: practical cost-effective method for sterilizing urinary catheters in the home

We used a standard microwave oven to sterilize red rubber catheters used for intermittent self-catheterization. Catheters were incubated for sixty minutes in a suspension of microorganisms isolated from the urine of patients with urinary tract infections. For each trial, 6 catheters were removed from their respective suspensions, placed in separate plastic freezer bags, distributed evenly in a microwave oven (avoiding cold spots), and microwaved simultaneously for twelve minutes. A control catheter was not microwaved. Two strains of each microorganism were tested. The urinary isolates were Escherichia coli, Klebsiella sp., Proteus sp., Enterobacter sp., Pseudomonas sp., Streptococcus sp., Staphylococcus sp., and Candida sp. In each experiment, all 6 catheters were sterilized. Repeat sterilization in the microwave oven did not affect the integrity of the catheters or the plastic bags. A water heat sink of constant volume was employed. A home microwave oven may be used as a method to sterilize red rubber catheters for reuse with a recommended time of twelve minutes at full power. This technique makes aseptic intermittent self-catheterization a practical possibility.     

Complications of chronic indwelling urinary catheters among male nursing home patients: a prospective study

We studied prospectively the incidence of symptomatic infections of presumed urinary tract origin requiring antimicrobial therapy among 54 male nursing home patients with chronic indwelling bladder catheters. During 514 patient-months at risk there were 106 episodes of symptomatic infection, for an incidence of 0.21 per patient-month at risk. Of the patients 80 per cent had at least 1 episode and 48 per cent had 2 or more. None of the clinical factors we examined, including age, nutritional status, stool incontinence, diabetes mellitus, episodes of catheter blockage and the use of chronic suppressant antimicrobial therapy, was associated with the development of symptomatic infection. Further research on host and pathogen-related factors that increase the risk for symptomatic infection, and improvements in infection control and catheter care protocols are necessary to decrease catheter-associated morbidity among male nursing home patients who must be managed by chronic indwelling catheterization.     

Suprapubic catheters: a comparison of suprapubic versus urethral catheters in the treatment of acute urinary retention

Sixty patients presenting with acute urinary retention were randomly allocated to treatment with either suprapubic or urethral catheters. An initial specimen of urine was obtained for bacteriological culture and organism count. Subsequently, repeat specimens of urine were obtained at intervals of 2 days until the catheter was removed. The results of these cultures showed that suprapubic catheters caused less urinary tract infection (P less than 0.05). In addition, suprapubic catheters were more comfortable for the patients, easier to manage and more cost-effective. In patients with suprapubic catheters, their ability to void could be assessed prior to removal of the catheter, thus avoiding the need for recatheterization. It was concluded that patients presenting with acute urinary retention should be routinely treated by drainage using suprapubic catheters.     

Cytotoxicity of latex urinary catheters

After an epidemic of severe urethral strictures in cardiac surgery patients, all brand latex catheters marketed in Finland were investigated for cellular toxicity with eluates made from the catheters. Four of the seven brands, including the one involved in the stricture cases, showed marked cytotoxicity and inhibited almost all cell growth in various human cell cultures when a 30% catheter eluate was used. DNA histograms of cells cultured with toxic catheter eluate showed inhibition of DNA synthesis. Silicone catheters did not influence cell growth, which correlates with the finding that no new stricture cases were seen after the latex catheters were replaced with silicone ones. Attention is paid to the facts that international standards regarding urethral catheter toxicity are lacking and that catheter quality control is insufficient.     

导尿管毒性的实验研究

导尿管的毒性物质是引起尿道感染和狭窄的重要因素之一。为进一步明确各种材料制成的导尿管的毒性大小，应用细胞培养的方法检测了７种导尿管毒性提取物对体外培养的鼠成纤维细胞（Ｌ９２９）摄入Ｈ＾３－标记胸腺嘧啶核苷（Ｈ＾３－ＴＤＲ）的抑制情况，并比较其毒性大小，结果表明：硅胶导尿管毒性很小，硅处理乳胶、塑料导尿管毒性中等，橡胶尤其是白橡胶导尿管具有较大的毒性。提示临床选用导尿管应考虑到导尿管的毒性，尽量选用     

Toxicity testing of urinary catheters

The tissue toxicity of 23 urinary catheter batches (6 latex and 2 non-latex brands) was tested in vitro and in vivo. In vitro, a human T-cell leukemia line (JM) was cultured in the presence of different concentrations of eluates made from the catheters. The cytotoxicity of the eluates was assessed from their ability to inhibit DNA synthesis measured by incorporation of 3H-thymidine. In vivo, two methods were used. Strips of catheters were implanted into the rabbit dorsal muscle and pieces of catheters were implanted into the rat peritoneal cavity. After four days, the foreign body reaction, type of inflammation and necrosis were quantified macroscopically and by light microscopy. The results of the in vitro cytotoxicity test were correlated with those of in vivo methods. The rat peritoneal implantation test correlated better with the cell culture test (P less than 0.01) than with the rabbit muscle implantation test (P less than 0.05). Based on the clinical experience of urethral stricture complications caused by urinary catheters, catheters yielding eluate which at 30% dilution inhibited 50% DNA synthesis were regarded as toxic. According to this, the rabbit muscle implantation test was not reliable in testing the tissue toxicity of urinary catheters, while the cell culture test was quantitative and seemed to correlate with both the rat peritoneal implantation test and with the clinical complications observed.     

Removal of retained urinary catheters

In a 1-year register, retained urinary catheters were encountered on 23 occasions. In vitro tests showed that 2 ml of ether or chloroform injected through the inflation channel of catheter balloons caused disruption within a few seconds but liquid paraffin took over 20 min, leaving an unacceptable amount of debris. A new method of removal using diagnostic ultrasound to identify the balloon of the retained catheter is described, together with suggestions for removal of retained catheters occurring under different circumstances.     

Transthoracic cuffed hemodialysis catheters: a method for difficult hemodialysis access

BACKGROUND: Recurrent vascular access failure is a major cause of morbidity in patients receiving long-term hemodialysis. Central venous catheters are often necessary for dialysis, and easily accessed vessels (ie, the internal jugular vein and subclavian vein) frequently occlude because of repeated cannulation. When standard access sites occlude, unconventional access methods become necessary. We report a technique of placing hemodialysis catheters directly into the superior vena cava (SVC). METHODS: Between January 2002 and December 2004, 22 patients with documented bilateral jugular and subclavian vein occlusion underwent transthoracic SVC permanent catheter placement. Femoral vein access was obtained, and a sheath was placed. Under fluoroscopic guidance, a diagnostic catheter was then inserted into the SVC, and a venogram was obtained. By using the fluoroscopic image as a reference guide, supraclavicular access directly into the SVC was performed with lateral and anteroposterior views to better localize the SVC. Once venous blood was obtained, a hydrophilic wire was passed into the inferior vena cava. A 5F sheath was then placed, and, with the use of an exchange catheter, the wire was switched for a stiffer wire. The hemodialysis catheter was then placed in the standard fashion over this wire. RESULTS: In a 24-month period, 22 patients underwent transthoracic permanent catheter placement. All patients had the permanent catheters successfully inserted. Two major complications occurred. One patient experienced a pneumothorax, and another patient experienced a hemothorax. Both patients were successfully treated with chest tube decompression. All permanent catheters functioned immediately with a range of 1 to 7 months. CONCLUSIONS: Transthoracic permanent catheter placement is an appropriate alternative for patients in whom traditional venous access sites are no longer available.     

Development of a novel method of female sterilization: I. The development of a novel method of hysteroscopic sterilization

BACKGROUND AND OBJECTIVES: For more than 100 years, gynecologists have attempted to effect sterilization via a transuterine approach. Our aim was to develop a safe, simple, rapid method of sterilization that could be performed in the outpatient clinic. The authors felt that a tubal screw based on a "self-tapping" screw would be less likely to become dislodged from the uterine cornu with time because multiple backward-pointing threads prevent it from being displaced. METHODS: During the development of the technique, many changes had to be made to deliver the tubal screw effectively to the uterine cornu. These involved overcoming problems of poor cornual distension before screw application, effecting the requisite deflection toward the uterine cornu, performing the screwing action with a deflected applicator, and finally disimpacting the screw. Changes were made to the tubal screw, hysteroscope, method of uterine distension, method of deflection, screw applicator, and method of disimpaction. RESULTS AND CONCLUSIONS: The system that appears to be the most efficient consists of a 25F cystoscope with a variable bridge, a 4-mm 30-degree endoscope, and an unsealed spring applicator with bayonet mounting on the screw applied with the use of a pressure bag for uterine distension with saline solution.     

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.     

Preliminary results with toluene for retained urinary catheters

Several methods for the deflation of a retained balloon catheter have been recommended. An experimental study was done to determine whether a better chemical could be made available for this problem. This preliminary report indicates toluene to be the better choice for such retained catheters.     

Adherence of bacteria to urinary catheters

Summary The adherence of ³H-labelled gram-negative bacilli to different urinary catheter materials was studied using an in vitro method. Adherence was found to be significantly less to siliconised rubber than to pure latex or teflon coated rubber. Adherence was altered by variations in incubation pH, time, and bacterial concentration; however, incubation temperature did not affect results. Adherence of bacteria to urinary tract catheters may be part of the pathogenesis of certain catheter-related infections. However, in the absence of controlled clinical studies the significance of these findings remains to be determined.     

Short-term electrical stimulation: home treatment for urinary incontinence

Summary Treatment results with short-term electrical stimulation therapy in 310 incontinent patients are reported. Cure or improvement was obtained in 56% of cases. This therapeutic method was well-accepted, especially as a home treatment program.     

Long-term indwelling silicone catheters: a simple, safe method for venous access

The increasing long-term use of intravenous chemotherapy has resulted in problems of venous access for a number of reasons, one being the sclerosing action of the drugs used. Silastic catheters were introduced to ameliorate this problem, initially with some caution because of potential complications and the lack of necessary equipment. The purpose of this paper was to show that the procedure is simple, effective and associated with few complications. Ninety-six patients (32 men, 64 women) with lymphoma (25), leukemia (28), metastatic breast cancer (28) or other malignant lesions (15) were referred for insertion of a Silastic permanent indwelling catheter into the superior vena cava. The catheter was inserted through a subclavian vein using a Cordis Vein Dilator Kit, itself introduced over a guide wire inserted initially under fluoroscopic control. Local sepsis at the insertion site occurred in 6 of the first 43 patients treated but in none of the remainder. Six catheters became thrombosed and required revision. There were no instances of bleeding, air embolism or pulmonary complications. Patient acceptance of this method of venous access was high compared with that for peripheral, repeated venepuncture.     

Spontaneous knotting of urinary catheters: clinical and experimental observations

Urinary catheters are known to spontaneously knot inside the bladder. Approximately 40 cases of this complication have been recorded in the world literature. Clinical observation in 4 children and simulation experiments done using a balloon model are described herein. Risk factors identified in this study includes catheter size less than 10 Fr, overdistended bladder and insertion of more than 10 cm length of catheter inside the bladder. Water-current generated by the flow of urine appears to play an important role in the pathogenesis of catheter knotting.     

Intraluminal pneumatic lithotripsy for the removal of encrusted urinary catheters

PURPOSE: Urologists frequently treat patients requiring long-term urinary drainage with a percutaneous nephrostomy tube or ureteral stent. When such tubes are neglected and become encrusted, removal challenges even experienced urologists. We describe a new, minimally invasive technique for safely and rapidly removing encrusted, occluded tubes using the Swiss Lithoclast pneumatic lithotriptor. MATERIALS AND METHODS: Patients presenting with an encrusted urinary catheter were evaluated by excretory urography for renal function and obstruction. Gentle manual extraction of the tube was attempted, followed by traditional extracorporeal shock wave lithotripsy and/or ureteroscopy. When the tube was not extracted, patients were then treated with intraluminal insertion of a pneumatic lithotripsy probe. RESULTS: One patient presented with an encrusted, occluded nephrostomy tube and 2 had an encrusted, occluded, indwelling ureteral stent. None was removed by manual traction. Intraluminal encrustations prevented the pigtail portions of these tubes from uncoiling and removal. In each case a pneumatic lithotripsy probe was inserted into the lumen of the catheter and advanced in a jackhammer-like fashion. This technique resulted in disruption of the intraluminal encrustations and straightening of the tubes so that they were removed in an atraumatic manner. CONCLUSIONS: Intraluminal pneumatic lithotripsy is a safe, easy and rapid technique for removing encrusted urinary catheters. It is unique in that the pneumatic lithotripsy probe functions in an aqueous and nonaqueous environment, and dislodges intraluminal calcifications. We recommend its use as first line treatment for removing encrusted urinary catheters.