Urodynamic study (UDS) is a very common measurement way to measure the urethral and bladder’s function which based on fluid mechanics and electrophysiology. [1] It is widely used in the clinical diagnosis of various of diseases in the urological clinical works, especially in the use of urinary continence and gynecology . Urodynamic study is an invasive examination way, for the bladder pressure measurement purpose, we must put the measurement catheter via urethral into bladder, and this process may injure the urethra and bladder’s mucosa and lead to bleeding, especially in patients with prostate hyperplasia and urethral stricture . In the past urodynamic study , for patients with indwelling catheter, the indwelling catheter should be pulled out in the process of urodynamic examination first, and then the special urodynamic measurement catheter should be put into the bladder via urethral according to the routine examination, after the examination, the catheter urodynamic measurement catheter should be pulled out again and the urinary catheter should be inserted again. Therefore, the invasive catheterization process needs to be performed twice during the whole examination , which brings a great pain and injury to the patients. However, for this part of patients with indwelling catheter, urethral conditions are often poor for our to put the urodynamic measurement into bladder, and they are more prone to bleeding during this process and get infection after study. Numerous of patients  due to various reasons of urinary dysfunction in clinical practice should be in indwelling catheter. So how urodynamic study for this portion of patients can be satisfy the clinical urodynamic study data collection and avoid repeatedly catheter for patients with injury and pain, in clinical urodynamic study work we found that the current indwelling catheter tube diameter of 12 fr, and is commonly used in clinical indwelling catheter diameter range from 8 fr - 16 fr.12 fr catheters, which are frequently used, and in clinical research showed that a lot of urine flow dynamics diameter under 12 fr pressure catheter tube will not significantly increased urethral resistance leads to the artifacts of the test results. [2] Therefore, we consider whether can use in patients with retention of urine tube directly as pressure in patients with pathway, using specially equipment to connect devices to urine tube and pressure transmission tube connected to inspect, the main purpose of this study was to evaluate the special connection device in patients with retained ureter urine flow dynamic test of the efficacy and safety.

45patients who were with indwelling catheter were contained in our research group, there were 22 male patients and 23 female patients ,and the mean age were 43.5±10.86 .Excluded criteria:1. Actue urinary tract infection 2.congnition disorder3.age<18 4.urethral stricture.5.patientsl were not with catheter before test.ALL urodynamic study were done by an urodynamicist with at 5 years experience and results were readed by an urologist with at least 10 years experience. All 45 patients had recieven 2 times urodynamic study ,the first time using normal process to test（control group） and the second time using the special connection equipment to connect the indwelling catheter and the urodynamic measurement tube(study group). Urodynamic measurements during the two times test in each patients were observed ,the bleeding ratio during and after test, VAS score were all observed.

Through urine flow mechanics in the experimental group and control group respectively, we found that the experimental group and control group patients with corresponding urine flow dynamic positive detection rate are consistent, the experimental group checked out of 15 patients with detrusor contractions fatigue; Bladder outflow tract in 21 patients; Low compliance bladder in 7 cases; There were 2 cases of detrusor hyperactivity, and all positive results were consistent in the same patient in both groups. Bleeding occurred in 1 case (2.2%). In the control group, 8 patients (17.7%) had bleeding during the examination. During the examination, the average VAS score of the experimental group was (1.12 0.58). The average VAS score of the control group was 3.88 1.01. 2.1 the experimental group and control group patients with urinary flow mechanics test results is the same in the two groups of different experimental detection rate and detection in the process of disease (positive), the detection rate and disease there is no statistical difference of detection rate. The experimental group and control group in the process of checking bleeding group in the process of testing result in bleeding patients for 1 case (2.2%), control group adopts the traditional way of examination hemorrhage patients in the process of 8 cases (17.7%). Comparison of the two groups showed that the bleeding rate in the experimental group was significantly lower than that in the control group (P<0.05), and the difference was statistically significant, as shown in table 2. In the experimental group and control group check, check after the pain score of two groups of VAS score after check in and check the experimental group were lower than the control group (P < 0.05), statistically significant difference, specific see table 3.

The special connection equipment using in the urodynamic study for the patient with indwelling catheter can decrease the bleeding ration and pain during and after test under the condition of not increase the risk of artifacts happening ration.

The special connection equipment using in the urodynamic study for the patient with indwelling catheter can decrease the bleeding ration and pain during and after test under the condition of not increase the risk of artifacts happening ration.

Schafer W, Abrams P, Liao L, et al. Good urodynamic practices, uroflowmetry, filling cystometry, and pressure - flow studies [J]. Neurourol Urodynamics, 2002, 21 (3) : 261-274.
Nitti vw editor. Urine dynamics [M]. Beijing: People's military medical press, 2014, - 56.