SCINurse - Significance of bladder compliance and high pressure

[TD]

I had a urodynamics study done a while back and have obtained a copy of the urologists report and chart. I sure wish these doctors would translate some of this jargon for me. Words like "severe detrusor hyperreflexia" remind me of Autonomic Dysreflexia and I know how dangerous that is for me.

I apparently have good bladder compliance up to 450 cc and I know my bladder tends to trigger and I pee at about 500 - 600 cc. (I have always had a large bladder, even when I was AB. ) What does this mean? The report talks about having high pressure bladder spasms as well. The chart stays around 31cmH2O until it hits 464 ml. Then my bladder triggers and it starts to climb. I think my sphyncter opens somewhere between 50 and 70 cmH2O. During the test, the tech would not let my bladder dump like it normally does. She allowed the pressure to climb to 103 before allowing me to pee. I am wondering if this isn't skewing the urologists' findings. I started out having to cath only once a day but when the UTIs became a problem I went to three times a day. I haven't had a UTI since!! (knock on wood )

I heard how high pressure can damage your kidneys. How does it do that and how high is too high? I pee every three hours and sometimes after I pee I cath. I pee as little as 100 cc and as much as 400 cc. The residual I have ranges anywhere from 200 ml to 450 depending on how hard I concentrate on my bladder muscles.

A lot of people in these chat rooms tell me to cath before my bladder gets to 400 cc but according to my urodynamics study I can go even longer. How do you know when your bladder is getting full when you can't feel it? This is making me nuts!!!

"And so it begins."

[SCI-Nurse]

I will try to address all your questions as best I can.

Generally high pressures are defined as any pressure inside the bladder over 40 Cm. of H20, either at rest or while voiding. Most ABs never exceed 20 Cm of H20 even when voiding. The reason that 40 is significant is that is the maximum pressure that urine draining down your ureters can exert. If your bladder pressure is higher, then the urine cannot drain from your kidneys into the bladder, and damage to the kidneys can occur over time from the back pressure.

How did the tech prevent you from peeing? In my experience doing urodynamics, if your bladder is trying hard to empty you would generally leak around the catheter (usually only a 6 or 7 Fr. catheter should be used).

Most people who do intermittent cath do not have sensation, so they need to learn to monitor their fluid intake to judge when they will next need to cath. Since your pressures go up at about 450 cc. that is the maximum amount you should ever have in your bladder, regardless of your previous bladder capacity when you were AB. A residual of 200-400 cc. is way too high...it should consistently be below 100 cc. if you are voiding. Higher residuals significantly increase your risk for UTI. Do you wear an external or have enough sensation/control to use a urinal or the bathroom?

Meds such as Ditropan, Detrol and/or imipramine can usually be taken to reduce your pressures to safe levels, but this may mean cathing on a regular basis only and not peeing at all.

If you do not want to cath, the next option would be to have a procedure such as a sphinterotomy or urethral stent. Opening and keep the external sphincter open often will reduce your pressures to safe levels, but at the cost of having to use an external continuously.

Other than than the options include surgery (bladder augmentation) which would reduce your pressures but generally result in needing to cath or use of an indwelling catheter (urethral or suprapubic). (KLD)

[SCI-Nurse]

I will also add a bit of information to what KLD has already supplied.
While the bladder is filling, it should do so at very low pressures (not much above zero) until capacity is reached. So if the chart is staying at 31 until it is full, that is considered much too high.
The capacity of 450cc doesn't mean your bladder is compliant. In urodynamics terms, compliance is a ratio of volume over pressure. A compliance ratio of 20 or more is desired. Therefore, if, say, your volume was 100cc with a pressure of 30 as you said, your bladder compliance would be 3 and therefore puts your kidneys at risk. Most of the time, we check bladder compliance at 1/3, 2/3, and full. Urologists don't want to see bladders filling at high pressure as this puts the kidneys at constant risk, which over time, may lead to problems with the kidney and ureters. Continuous pressure at the valves eventually leads to them becoming weak and allowing backflow.
The bladder should not be spasming. The detrusor pressure line shouldn't be going up and down on the urodynamics graph. This is a hyperreflexic bladder.
It sounds like you need to be taking medication such as KLD described. This may block down your bladder completely and you may have to cath at all times. Though this probably isn't what you want to be doing, it will save your kidneys. (EMK)

[quadfather]

I'm 15 years post. I don't cath, just wear an external. I haven't had a cystogram in 13 years and the last IVP I had was 5+ years ago.

My doc does annual blood test for kidney function and I haven't had a UTI since I stopped cathing 14.5 years ago. Do I need to go through the enjoyment (and risk) of a urodynamics test?

[SCI-Nurse]

Urodyanmics are still important. As the saying goes, the "kidneys suffer in silence". You must loose over 60% of your kidney function before your blood levels of BUN or creatinine become elevated. At that point it may be too late to remedy any changes in the bladder and spare further kidney damage.

In addition to these blood tests, it is recommended that you have renal and ureter ultrasound annually (IVP only if abnormalities noted) and urodyanmics every 2-3 years unless using an indwelling catheter. (KLD)

[TD]

KLD - Okay, I understand that 40cmH2O of pressure is maximum. So when my bladder spasms to void it may be causing back pressure which could damage my kidneys. It is strange that my PMR recommended only once a day cathing to empty my bladder but I will address that with her. I have recently begun cathing three times a day to avoid UTIs, an increase I did on my own after six years of cathing once a day.

I am not certain how the tech prevented me from peeing. I was lying down watching the cystometry monitor and not paying much attention to her. I only know she prevented me from voiding because of the excruciating pain I suffered until she did something that allowed me to pee. Under normal circumstances (for me), I would have voided anywhere from 200 cc to 300 cc long before the graph hit its high of 103. She has 70 cmH2O marked and I think that is where my bladder sphincter normally opened. Your response tells me this is still too high. I believe she used a 6 French catheter to fill my bladder. I had to have leaked around it because I sometimes leak around the 14 French I normally use.

There are areas on the report called "Results (storage phase)" where the "Vinfus", "Pdet", and "Compliance" are simply marked "N.A.". At the bottom are the words "Normal Capacity" written in. This leads me to believe that the 450 cc. mentioned in the letter to my PMR is my normal capacity.

I suppose I am not your "normal" SCI because I have sensation, especially when I am about to pee. I get the urge about 2 or 3 seconds before my sphincter opens up and I pee. This is why I wear a condom all the time. 2- 3 seconds is not enough time to wheel into the bathroom or even grab the urinal. I know this from experience.


I am currently drinking between 2000 cc and 3000 cc of water on top of what I take in with my meals. My bladder makes up its own mind when it wants to void. I also suffer from mild to moderate brain damage affecting my short to long term memory and motivation. This can cause problems when it comes to remembering to cath regularly. Taking any of the bladder spasm drugs could cause serious problems for me since I could inadvertantly allow my bladder to reach 1000 cc. This occurred twice while I was in rehab because my nurses forgot to cath me. I was in a halo brace and leg casts at the time so it wasn't my fault!! This I KNOW to be dangerous!!

I will make it a point to have a urodynamics study done regularly, possibly annually. It urks me that my PMR waited 6 years to have one done. At least she has been ordering annual ultrasounds and they have been coming back as normal.

EMK - Perhaps I was not clear in saying the pressure was at 31 cmH20. The pressure stayed low (possibly near zero) until the volume reached around 400 then it slowly rose until reached 460. That was when the graph jumps.

The letter from the urologist to my PMR states "Significantly, the patient did have good bladder compliance up to this volume (450cc)." From looking at the chart I believe my pressure while filling is well below the 31cmH20 I refered to earlier. It is only when it reaches the 450 mark that it begins to rise and when it reaches 464 it jumps. The detrusor pressure (Pdet) is relatively flat until this point as well.

I still need to address the problem of when I should cath. There seems to be no uniformity to when my bladder decides to pee. I have cathed and then my bladder has voided within a half hour. At other times, I have gone as much as five or six hours before peeing. I cathed immediately and had residuals of between 300 and 400 cc. I was drinking pretty much the same amount of water on these occasions. I will have to give serious consideration to having a sphincterotomy done.

"And so it begins."