Fluid Replacement on Weight Basis

susswood · Jun 5, 2006

Assuming an 8 hour fast, I would replace an (approximate) one liter deficit over the first three hours combined with 120 ml/hr maintenence and add 800 ml/hr (give or take) for insensible losses during a period of maximun exposed surgical area. Careful attention to hemodynamics (obviously) and, of course, I would follow my urine output very closely (volume and color) and adjust as needed keeping a minimum of about 40ml/hr. She may end up getting about 10-11 liters, maybe more-maybe less....

Was liposuction done as well? I know there can be additional issues if wetting solution is used... I am not very familiar with plastics.

Anyhow, that's my stab at it.

athomas91 · Jun 6, 2006

yoga - man...if you go on the numbers along - she would get a load of fluid - 130cc/hr is maint. based on weight (even though she is still about 30-40 lbs over weight)

an eight hour deficit -( which is more than likely a 10 or 12 hour deficit) - would give you a 1-1.5L loss.. 900cc to replace blood loss w/ crystalloid...

i would load her up in the first hour with 2L - i would then maint her at 150cc/hr and follow urine output.. i would likely use 500-1000cc of hespan to decrease the swelling that will ensue from the fluid we need to replace.

overall i can easily see giving her 5-6 L + 1000cc of hespan and give add'l fluid based on u/o and hemodynamics... for me it is one of those have to be there cases... i assume that otherwise she was healthy as she was done in an surgical center setting...

TheLemur · Jun 6, 2006

My thoughts:

This lady is no longer "obese", with a BMI

Maintenance fluid requirements are approximately 135cc's/hr (weight in kilo's +40), and you want to replace the deficit sooner rather than later (1/2 first hour, 1/2 second hr or whichever method you prefer).

Obligatory loss for your case was probably high; I'm thinking an additional 8-10ml/kg/hr, or almost a litre an hour. Replace blood and urine loss appropriately.

But I realize that the above is more guideline than reality. How much colloid vs crystalloid? For a case that long, I would want to keep what I'm giving her in the intravascular space, so hextend (up to 1.5L) or plasmanate would be prudent for at least some of the volume. I did an abdominoplasty several weeks back, and I remember being in t-berg for most of the case, so pulmonary edema is a concern. More reason to not use crsytalloid only.

How much of which, and at what point do you want to check labs for electrolyte imbalances / hemodilution? And how do you manage this along with the hemodynamic status of the patient? This is the "art" stuff that I'm still getting a sense for. And I'm sure I'm not including some important details.

Thanks for the learning opportunity.

Focker, CRNA · Jun 6, 2006

I didnt look at any of the other posts yet so that I could see how my answer compared. At 200 pounds, she is about 90 kg so her hourly maintenance would be 130 mL/hr LR. After 8hrs fasting (assumed) her deficit would be 1040 ml, replacing half the first hour, and a quarter the second and third hour. With this type of surgery I would thing the third spacing and evaporative loss would be large, so 10 mL/kg/hr of LR should be administered (900 ml/hr). For the third spacing, I'm not sure that I would want to continue with that rate for the entire ten hours of the surgery, that seems like a ton of fluid, hopefully others with more experience will have better input. I would want to give colloid like hextend or hespan (max one liter) on about the third liter of fluid to recruit fluid to the intravascular space. Definitely warm the fluids. So first hour, 1550 ml LR. Second hour, 1290 ml LR. Third hour, Liter of colloid like hextend (which should replace the 300 ml of blood loss and put her ahead a little bit fluid status wise). Basically, a liter of fluid every hour after that for the rest of the surgery, but I would probably want to actually give less than that depending on urine output, hemodynamics and her history.

Questions I would have are:

Should have used her ideal weight versus her actual weight (or calculated weight which falls in-between)?

Even given the large amount of third-spacing, would I really want to give a liter an hour for the last 6-7 hours of the surgery? (formula we learned in class says yes, intuitively it seems like overkill, but if her kidneys are perfused she should be able to get rid of the excess. I need input here)

Tranman · Jun 6, 2006

You guys are all Wrong!!! Just kidding. Great posts all. Yes i would do the math and use the numbers as a guideline but would titrate my fluids according to the urine output and BP. If she is making good clear urine throughout the case and the VSS are stable (BP w/i 20% margin), I wouldn't worry about giving all the fluid I've precalculated. I would definitely give Hespan as well, but would limit it to 1000cc. Seems most people are comfortable giving no more than 2 bags of hespan a case, but we are talking about a 10 hour case here. If I was in T-bird for any significant amount of time towards the end, I would definitely sit her up and allow the any third spaced fluid to drain for at least 10 min before extubating. And it goes without saying, she should be extubate awake.

Wow 300 cc bld loss for a 10hr case is indeed excellent. If the surgeon loss any more. Say 600-800, I wouldn't hesitate to give her blood either, especially if I know it'll be a long ways from being done. That's just me though.

yoga crna · Jun 6, 2006

, she should be extubate awake..

I don't extubate abdominoplasty patients awake, but actually quite deep. I deflate the cuff slowly, extubate and mask ventilate until awake. The reason--if they buck on the tube they can pop all of their deep muscle abdominal sutures. I had it happen once and you could actually hear the sutures popping. The patient had to be anesthetized again, opened and resutured. Once that happens, you never forget it.

I actually kept her dry fluid-wise. She had totally stable vital signs, urine output of about 35-40 ml/hr, no postural hypotension when put in the semi-sitting lawn chair position or when we turned her lateral to lateral for the thigh and buttocks lift. I gave her 5 liters of warmed crystalloid, which I thought was on the dry side, but had a hard time justifying pushing fluids if she didn't need them. Also, she had 2000 cc of tumescent fluid prior to the liposuction and only 600 cc aspirate.The surgeon asked that I not give hespan, because he has had a bad experience with increased bleeding after hespan use. The plastic surgeons really worry about bleeding. She did well, was awake in PACU with the same vitals as on admission. We will see how she does tonight. She is with our after-care RN, who also is an ICU nurse and who does a great job of taking care of these patients the first post-op night. I'll let you know how she does.

Thanks for the input.

yoga crna

Tranman · Jun 6, 2006

I normally extubate most of my patients deep anyway. I understand your point about popping stitches, but I would be hestitant to extubate deep on a 10 hour case with 600-800cc bld loss neccesitating lots of blood and fluids and having spend any significant time towards the end of the case in T-bird. Meaning if I had significant 3rd spacing and/or any trouble with the intubation. This is a hypothetical situation I'm talking about here.

Obviously this is not how your case went and the surgeon only loses 300cc bld loss normally. So in this case, yes deep extubation. You can also do awake extubations without coughing/bucking or minimal coughing/bucking. Lido ETT while deep prior to extubation, and make sure you have enough Narc on board. Also surgeon should have the abdominal binder on before you pull the tube anyway.

Remember also that you are dealing with a post Gastric bypass patient. One who has a very small stomach. These patients are at high risk for reflux all the time which is a contraindication to extubating deep. So do I deep extubate pt's with a history of reflux? Selectively yes. Usually if they are also not obese or if I didn't have any trouble with the intubation.

If having had your experience with popping abdominal sutures, I understand your hesitation to extubating awake. I too would probably extubate deep despite the risk for reflux. I see the risk for reflux as less likely than the risk for popping sutures, so I agree with you there. Just making sure all areas have been covered first.

yoga crna · Jun 7, 2006

Follow up--Patient did great, vital signs totally stable all night. Post-op hematocrit 32. The only problem is that the patient did not tell us that she is very claustrophobic and she freaked out in PACU when the oxygen mask was placed on her face. She didn't even tolerate nasal oxygen very well. A little morphine and po diazepam helped the situation and she slept most of the night. Off to aftercare today and the last report was good.

Thanks for all of your answers. I am impressed with the level of sophistication on this board by the anesthesia professionals. Cases like this make you realize how much we have to know in this field.

Keep the clinical scenarios coming.