Straight caths - to clamp or not to clamp?

[SaraO'Hara]

Today, I had a patient retaining urine - over 1500cc out with straight cath. An experienced coworker insists that one must either remove or clamp the straight cath after 1000cc output, lest the patient descend into a hypovolemic state. Based on her statements, I monitored the pt's BP and HR for the rest of the shift - no significant change.

I have been scouring my nursing textbooks and searching online - I can't find any evidence for the need to clamp off and wait after 1000cc out. I have a few basic problems with the idea:

1. Risk of bladder damage, hydroureter, pyelonephritis, etc.

2. The bladder is just plain not part of the circulatory system.

3. Why don't I get hypovolemic letting a liter off at the end of a busy shift?

Thanks, everybody!

[talaxandra]

This is something that a lot of nurses say but, as the OP points out, isn't based on anything that makes sense. It's been discussed on AN previously, with the same result - there's very little actual data. I've just done a google scholar search using various permutations of: clamp, urine, catheter, volume, danger, risk, spasm, shock, dilate, and hypotension. And the only relevant information that came up had to do with autonomic dysreflexia.

However, once I added "myth" to the search I found the following from Abdominal Emergencies by David Cline and Latha G Stead (McGraw-Hill, 2007):

Rapid decompression of the obstructed urinary bladder is safe and effective.Hemturia, hypotension, and post obstructive diuresis are rarely clinically significant. The exception is cases of high pressure chronic retention, seen most commonly in BPH. (p. 169)

and

It is widely taught that once the catheter is in place, the rate of bladder emptying needs to be carefully controlled. in fact, this is largely a myth. There are two complications that can be induced by rapid bladder decompression: gross hematuria and reflex hypotension. The risk of gross hematuria resulting from sudden release of pressure on compressed veins on the bladder wall is 2% to 16%. However, the bladder pressure is very sensitive to the release of small amounts of urine. The pressure is reduced by 50% after the removal of 100mlL. Clamping the catheter at 500mL or 1000mL is unlikely to prevent hematuria and if it does occur, it is most often self limiting. An extensive review by Nyman recommends rapid , complete emptying of the obstructed bladder in all cases. (p. 170)

Which lead me to this 1997 meta analysis of the literature. To summarise: there's no need to clamp, but elderly and compromised patients should be closely monitored.

[P_RN, ADN, RN]

1. Most of the quads I worded with in vocational rehabilitation cathed themselves and emptied their bladder.In the very old days of my career This was the fashion (74-78) but now days the urologists I know say let it all flow out if there is a problem call. You can always put some sterile water back in.
   

[catshowlady]

If that were the case, wouldn't we have bladder spasms every time we pee? I know I routinely pee more than 500 ml at a time.

When I first started working as a PCT and was getting used to infrequent bathroom breaks on my busy, busy floor, I used to get bladder spasms when I did finally get a chance to pee. They hurt!

I don't if my bladder just got used to holding more, or if I got smart enough to take bathroom breaks when I needed them.

:paw:

[AnaCatRN]

In nursing school, clamping was only mentioned in relation to possible autonomic dysreflexia in spinal cord injury patients, but I have heard other nurses swear it applies to everyone. Maybe some nurses think it's better to be safe than sorry? I've never heard of anything bad happening to anyone if the cath wasn't clamped.

[Virgo_RN, BSN, RN]

I was taught to clamp at 500-600ccs in nursing school, but this not the standard practice in the real world. The rationale was bladder spasms.

[RNperdiem, RN]

I wonder how much urine I voided at a time in my first nursing job? Only going once or twice a shift?

Nurses would be a good group of people to study in this subject.

[CrazierThanYou]

When I was doing clinicals for CNA, we were called into a patient's room to watch a nurse do a cath on this man. She grabbed his member and squeezed it as hard as she could (it appeared) and rammed the catheter in and then started cursing the doctor. She explained to us that they were having to cath him because ALL urine has to be removed while urinating or else an infection will set up. But, in the years since then, I have always suspected that every drop of urine ISN'T expelled during urination.

As an aside, I still don't see how she got the cath in, considering how hard she was squeezing his member...

[casi, ASN, RN]

We got postings all over work now that say this isn't necessary. I think it's an old school nursing thing that has hung on.

[GFockerRN]

Just straight cathed a severely distended 89 yo female, 1600ml removed with >100ml retained on bladder ultrasound. No change noted in BP before, during or after.

Initially I clamped after 1000ml for about 10 min because another RN told me it could make her hypotensive. I have heard this before but have never seen any literature to prove or dispell it... Deceided to remove clamp and continue to monitor closely... Patient definately more comfortable. VS stable.

[sunnycalifRN]

I don't know about bladder spasms, but what we were taught in nursing school is that too rapid emptying of the bladder can cause a vagal reaction . . . anyone ever experienced "pee shivers" after rapid urination (you *really* had to pee!)

However, I have long forgotten the volume limits on straight cath'ing a patient with urinary retention.

[MizAnnie]

This is an older article, but I think it supports the 'no clamp' concept:

http://www.mayoclinicproceedings.org/article/S0025-6196(11)63368-5/pdf

[nurseprnRN, BSN, RN]

https://allnurses.com/nursing-student-assistance/hypotension-its-causes-646548.html

Cites studies. This is nonsense.