Last year, my facility changed from making only custom 3:1 TPN solutions mixed by the pharmacy to having pre-mixed bags of TPN to use primarily and custom when needed. As a dietitian, I loved being able to provide my patients with the exact nutrition I felt they needed. On the other hand, this is a (supposedly) a large cost saver, so I knew the winds of change were coming. The pre-mixed bags are somewhat cheaper in material costs, but it is the man hours where the most money is saved.
I have come to not hate the pre-mixed bags. There are many patients who can meet their nutritional needs with these. They are quite easy to find the appropriate solution and rate and that saves a lot of time. The pharmacists seem to appreciate their time savings as well, so harmony for all!
When do we choose the pre-mixed?
Our facility has decided to primarily use pre-mixed options over custom for the majority of patients. All patients that have PN initiated start with what we call the “starter bag” which is a pre-mixed peripheral solution. This first bag can be infused through a central access or a peripheral access. It is the solution of 4.25/5 without electrolytes, and it is infused at 42 ml/hour per our standing order. This is infused the first 24 hours of infusion. The patient will then change to a mix that is a higher calorie/protein ratio (if they have central access) the next day or will have an increase in rate of this solution.
Starting PN at a low rate with lower macronutritents is in line with the guidelines for feeding slowly to avoid refeeding syndrome. It also gives us the opportunity to check labs and supplement as needed. We are also able to start sliding scale insulin and control blood sugars ahead of time. I was wary of using solutions without electrolytes because I had no experience with it. It turns out, it is fine for most patients to be on a solution without electrolytes for several days.
We try to keep patients on the pre-mixed bags of tpn. There are times that we need to order specialty tpn though.
When do we choose speciality TPN?
We choose a specially mixed TPN when it is what is best for the patient. At our facility, it is generally left up to the dietitians to make that call, but we are generally in close discussion with our clinical pharamacists. Here are some reasons
- Extreme electrolyte abnormalities that require more than iv supplementation.
- Patients that need a higher volume than 2 liters per day. (Our facility has an issue with ordering over 2 liters per day in our computer system)
- More calories and protein are needed than what can be provided with a pre-mixed solution.
- A more concentrated solution is required.
How to order pre-mixed TPN
We use Baxter products out our facility. They come with prescribing information and this graph that is easily used to assess what your goal rate and volume should be. Below is an example of 5/15 solution with electrolytes. To assess the rate needed for a goal, take how many grams of protein I want the patient to have and see what the rate for that amount is. Then see how many calories of dextrose and protein it provides and make up the rest with lipids given daily or several times per week to meet need. We calculate the average, on a weekly basis.
For example, a patient requires 75 grams protein and 1500 calories per day. Find where 75 grams of protein is under the amino acid column. Then I would see what rate that is. I do not like to order rates that do not end in a 0 or 5. (This is helpful for anyone trying to assess total fluid intake). According to this chart, I would either order the TPN at 60 or 65 ml/hr. to make the determination, I would then evaluate which one is going to hit closest to my calorie goal, adding either daily lipids (250 ml of 20% = 500 calories per day, or 250 ml 20 lipids 5 times per week would provide an average of 357 calories per day from lipids)
For this patient, I would choose the 65 ml/hour with daily lipids. It is a little above what my goal is but I also know that TPN is often turned off during the day for procedures, baths, etc.
What is better, pre-mixed or specialty?
My experience has always been making up our own tpn and providing the patient with the exact amount of macronutrients, micronutrients and electrolytes that they needed. It was difficult for me to give that up because I felt it was always what was best for the patient. It seemed that going to pre-mixed was more about cost savings than patient care. I am not wrong, and at the same time, many patients seem to fit within the premixed boundaries and are provided adequate nutrition. I guess you could say I have (pre) mixed feelings about it.
There seems to be an urban legend surrounding TPN in that it costs thousands of dollars per bag. It does not. When the costs for materials were broken down between premixed and specialty, the pre mixed was less expensive but not by much. The savings is in labor. That savings is also less than you would think because even the premixed bags have to be taken to the “hood” and injected with MVI, trace elements, etc by staff. So, someone in pharmacy still has to suit up and go into the specialty area to mix them. It is just less time, and that is the cost savings.
One could argue that the cost savings is then even less when nursing staff have to spend more time hanging 12 hour bags and running lipids separately every day (vs a 24 hour 3:1 bag). Also, one has to take into account the cost of tubing, which doubles when bags are changed every 12 hours.
Love it or hate it
I hate that we cannot be as controlled with the amount of nutrition we are giving patients. I hate that the nurses have to do more work. I hate that by using pre-mixed bags we are giving the impression that specific nutrition needs are not important.
I love that is is less work for pharmacy. I love that it is less work for the dietitians. I love that at our facility, tpn can be changed to meet the patients specific needs if we deem it necessary. That is a privilege that will most likely be short lived.
Love it or hate it, pre-mixed is her to stay. We make do the best we can!
I anyone has any questions, please drop a comment and I would be glad to try to answer it!