Clinical evaluation of a safety-device to prevent urinary catheter inflation related injuries

OBJECTIVE: To evaluate the feasibility of a novel “safety-valve” device for preventing catheter related urethral trauma during urethral catheterization (UC). To assess the opinions of clinicians on the performance of the safety-valve device. MATERIALS AND METHODS A validated prototype “safety-valve” device for preventing catheter balloon inflation related urethral injuries was prospectively piloted in male patients requiring UC in a tertiary referral teaching hospital (n = 100). The device allows fluid in the catheter system to decant through an activated safety threshold pressure valve if the catheter anchoring balloon is misplaced. Users evaluated the “safety-valve” with an anonymous questionnaire. The primary outcome measurement was prevention of anchoring balloon inflation in the urethra. Secondary outcome measurement was successful inflation of urinary catheter anchoring balloon in the bladder. RESULTS: Patient age was 76 ± 12 years and American Society of Anaesthesiologists grade was 3 ± 1.4. The “safety-valve” was utilized by 34 clinicians and activated in 7% (n = 7/100) patients during attempted UC, indicating that the catheter anchoring balloon was incorrectly positioned in the patient’s urethra. In these 7 cases, the catheter was successfully manipulated into the urinary bladder and inflated. 31 of 34 (91%) clinicians completed the questionnaire. Ten percent (n = 3/31) of respondents had previously inflated a urinary catheter anchoring balloon in the urethra and 100% (n = 31) felt that a safety mechanism for preventing balloon inflation in the urethra should be compulsory for all UCs. CONCLUSION: The safety-valve device piloted in this clinical study offers an effective solution for preventing catheter balloon inflation related urethral injuries

In vivo ureteroscopic intrarenal pressures and clinical outcomes: a multi-institutional analysis of 120 consecutive patients

  Objectives To evaluate the pressure range generated in the human renal collecting system during ureteroscopy (URS), in a large patient sample, and to investigate a relationship between intrarenal pressure (IRP) and outcome. Patients and Methods A prospective multi-institutional study was conducted, with ethics board approval; February 2022–March 2023. Recruitment was of 120 consecutive consenting adult patients undergoing semi-rigid URS and/or flexible ureterorenoscopy (FURS) for urolithiasis or diagnostic purposes. Retrograde, fluoroscopy-guided insertion of a 0.036-cm (0.014″) pressure guidewire (COMET™ II, Boston Scientific, Marlborough, MA, USA) to the renal pelvis was performed. Baseline and continuous ureteroscopic IRP was recorded, alongside relevant operative variables. A 30-day follow-up was completed. Descriptive statistics were applied to IRP traces, with mean (sd) and maximum values and variance reported. Relationships between IRP and technical variables, and IRP and clinical outcome were interrogated using the chi-square test and independent samples t-test.   Results A total of 430 pressure traces were analysed from 120 patient episodes. The mean (sd) baseline IRP was 16.45 (5.99) mmHg and the intraoperative IRP varied by technique. The mean (sd) IRP during semi-rigid URS with gravity irrigation was 34.93 (11.66) mmHg. FURS resulted in variable IRP values: from a mean (sd) of 26.78 (5.84) mmHg (gravity irrigation; 12/14-F ureteric access sheath [UAS]) to 87.27 (66.85) mmHg (200 mmHg pressurised-bag irrigation; 11/13-F UAS). The highest single pressure peak was 334.2 mmHg, during retrograde pyelography. Six patients (5%) developed postoperative urosepsis; these patients had significantly higher IRPs during FURS (mean [sd] 81.7 [49.52] mmHg) than controls (38.53 [22.6] mmHg; P  Conclusions A dynamic IRP profile is observed during human in vivo URS, with IRP frequently exceeding expected thresholds. A relationship appears to exist between elevated IRP and postoperative urosepsis.</p