Hi, Stebrunner and Family of CIC Practitioners, October 4th, 2017
Several months ago Stebrunner announced his newly discovered method of Catheter Insertion by blocking the funnel throughout the insertion stage. I set up some experiments in my lab which seemed to indicate that it was air trapped in the catheter lumen expanding as it warmed up to body temperature. The experiments were based on ColoPlast SpeediCath straight Hydrophilic catheters ranging from F-12 up to F-18. This explanation seemed too unlikely to be believable, yet it has proven to be the case many times since.
I adopted this technique myself and it worked beautifully at first but became progressively less effective as we moved into spring and summer. As the average room temperature rose from the winter 69F to the summer 76F the strategy began to fail. If my reasoning was sound, the closer the rising room temperature got to the body temperature, the less the thermal variation that would cause the air in the lumen to expand. So I took one of my 30 ml syringes, drew back the plunger to aspirate 5 ml of air and plugged the syringe into the catheter funnel. Then, as I gently pressed the catheter onto the inner (bladder) sphincter I depressed the syringe plunger. As soon as the air injected got to about 3 ml, in went the catheter, smoothly and painlessly just as it had always done in times past! Now, with the onset of winter I am back to the thumb-on-funnel routine.
I know, some will chastise me for injecting air into my bladder but, as long as the intent is to drain urine, most of the air in there will be expelled at the beginning of the stream moments later, providing patient remains standing or sitting. I am talking here of a relatively small amount of air (10 ml max.) spending a few seconds inside the urinary system. Greater quantities of air and longer time periods would call for an entirely different set of safety rules which are not relevant so are not mentioned here.
The first step before inserting anything into your bladder is to determine the current status of bladder, prostate, and urethra. Air based cystoscopies are becoming commonplace; mine was done over 70 years ago. However, complete expulsion of the air can take time, as in a day or two. This can be a noisy process. My plea to all practicing urologists, radiologists, and other related specialists, is to please warn your patients of this so that they do not choose a public restroom or, if at home, not be in earshot of the family for the first few voids, or they may wind up with a delighted audience gleefully applauding the performance!
Another important point is that my background is in mechanical engineering rather than in medical field, so “buyer beware!”. Finally, I haven’t a clue why or how the lumen air pressure should have such a dramatic effect upon sphincter performance. Your opinions would be very welcome.
Warm regards to you all. Alan86734.