Urethral catheter insertion forces: a comparison of experience and training

Purpose: This study was undertaken to evaluate the insertion forces utilized during simulated placement of a urethral catheter by healthcare individuals with a variety of catheter experience. Materials and Methods: A 21F urethral catheter was mounted to a metal spring. Participants were asked to press the tubing spring against a force gauge and stop when they met a level of resistance that would typically make them terminate a catheter placement. Simulated catheter insertion was repeated fives times, and peak compression forces were recorded. Healthcare professionals were divided into six groups according to their title: urology staff, non-urology staff, urology resident/ fellow, non-urology resident/ fellow, medical student, and registered nurse. Results: A total of fifty-seven healthcare professionals participated in the study. Urology staff (n = 6) had the lowest average insertion force for any group at 6.8 ± 2.0 Newtons (N). Medical students (n = 10) had the least amount of experience (1 ± 0 years) and the highest average insertion force range of 10.1 ± 3.7 N. Health care workers with greater than 25 years experience used significantly less force during catheter insertions (4.9 ± 1.8 N) compared to all groups (p < 0.01). Conclusions: We propose the maximum force that should be utilized during urethral catheter insertion is 5 Newtons. This force deserves validation in a larger population and should be considered when designing urethral catheters or creating catheter simulators. Understanding urethral catheter insertion forces may also aid in establishing competency parameters for health care professionals in training.

Randomized prospective evaluation of nephrostomy tube configuration: impact on postoperative pain

OBJECTIVE: Conduct a prospective randomized single-blind comparison of two nephrostomy catheter designs, evaluating specifically intraoperative placement and postoperative comfort. MATERIALS AND METHODS: The single-blind, prospective randomized trial was conducted with institutional review board approval. All patients undergoing percutaneous nephrolithotomy who gave informed consent were randomized to placement of either a Boston Scientific Flexima 8.3F pigtail nephrostomy tube #27-180 (PIG) or a Boston Scientific 8.2F nephroureteral stent #410-126 (NUS). Randomization was concealed from the surgeon until time of placement. Subjective intraoperative placement characteristics were rated by the surgeon on a scale of 1 = excellent, 2 = fair, 3 = good and 4 = poor. The patient's postoperative pain intensity was evaluated with a Visual Analog Pain Score (0 = no pain to 10 = worst pain). RESULTS: Nine patients were randomized to each group. The PIG group was rated significantly better than the NUS group with regards to ease of placement (p = 0.007) and radiopacity of the tube (p = 0.007) by surgeon. Visual analog pain scores on postoperative day one, was significantly lower in the PIG group (mean = 2+/-2) than the NUS group (mean = 5+/-1) (p = 0.004). The mean amount of intra-venous morphine equivalent given in the PIG group (mean = 1+/4 Eq morphine) was less on average compared to the NUS group (mean = 6+/13 Eq morphine), but the differences did not reach statistical significance (p = 0.06). CONCLUSIONS: Following percutaneous nephrolithotomy, use of a small pig-tail nephrostomy tube results in greater ease of placement and less postoperative pain than a nephroureteral catheter.