TEAM C SURVIVAL GUIDE: Answer to Question #1
- A. Your patient weighs 2kg. You found out on rounds this morning that his total fluid (TF) should be 130cc/kg/day. He will start TPN today with Protein of 1g/kg/day, Fat (IL) of 1g/kg/day and Dextrose of 10%. Calculate your patient's protein in g/L, fat in cc/day, total calories (TC), and rate of TPN. Hurry, your order needs to be in by 1pm.
First: For a TF of 130 cc/kg/d,
Calculate cc/hr: wt x TF divided by 24 (hrs/day):
2 kg x 130cc/kg/day =10.8cc/h
24h/day
Make sure that if you have other infusions (like any drips) you subtract them from the total fluids as your not going to be able to give as much fluid as TPN.
FAT
= Intralipid or IL. IL runs separately from the rest of TPN in the
NBICU. There's one standard fat concentration that we use, 20% intralipid
solution which has 0.2g/cc. So what we need to do is calculate the
amount of this solution to give each day, then convert that into an hourly
rate.
wt (kg) x F (g/kg/day)
= cc/day
0.2g/cc (20% concentration)
2 kg x 1 g/kg/day = 10cc/day
0.2g/cc
Now divide 10cc/day by 24h/day to get cc/hr:
10cc /24h = 0.4cc/h
Next determine how much TF is left for the dextrose and protein (which
run together at the same rate). To do this, subtract the rate of the intralipid
infusion from total rate:
Total cc/h = 10.8cc/h
Fat rate = 0.4cc/h
Dextrose and protein calculation 10.8 - 0.4 = 10.4cc/h
Now we have 10.4cc/h to run our protein and dextrose.
(10.4cc/h x 24h/day = 250cc/d)
Next let's calculate protein.
For protein we have to calculate the concentration of protein we want
in the TPN (ordered as g/L).
Protein (g/kg/day) = (L/d) x (g/L)
Wt (kg)
L/d = How much fluid you give through non-lipid TPN in a day
Change units to fit above formula:
10.4cc/h x 24h/day= 250cc/day
250ccx 1L/1000cc= 0.250L
Cross multiply and divide to solve for g/L in the above formula:
1g/kg/day = 0.250L/d x g/L
solve for g/L
2g/day = 8g/L protein
2kg
0.250L
Now when we order the TPN we order D10% P 8 g/L @10.4 cc/h and F at 0.4cc/h
B.
Your patient has been advancing TPN every few days.
On rounds this morning, you decided to increase to a P of 2.5,
F2, D15 keeping TF the same (130cc/kg/day).
Calculate as per question #1.
Like before, let's first calculate
how many cc's/hr would give a TF of 130 cc/kg/d for a 2 kg baby:
wt x TF = cc/hr
24h/day
2kg x130cc/kg/day = 10.8cc/h
24h/day
First calculate fat in cc/day:
wt (kg) x F (g/kg/d) =
g/day
0.2g/cc (20% concentration)
2kg x 2g/kg/day = 20g/d
0.2
Divide 20 g/d by 24hrs to get cc/h:
20g/d ÷ 24h/d = 0.83cc/hr
Next calculate the remaining total fluid for dextrose and protein. To
do this, subtract fat rate from total rate:
Total cc/h = 10.8cc/h
Fat rate = 0.83cc/h
TPN volume containing dextrose and protein: 10.8 - 0.83 = 9.97cc/h
Now calculate the protein concentration of the TPN:
Protein (g/kg/day) = (L/d) x (g/L)
Wt (kg)
rearranging the above formula to figure out the concentration of TPN in g/L:
Wt (kg) x Protein (g/kg/day)
= (g/L)
(L/d)
Now let's convert some of our units
to fit this formula:
9.97cc/h x 24h/d = 239cc/d
239cc/d x 1L/1000cc = 0.239L/d
Now, substitute into the formula and solve for g/L
2 kg x 2.5 g/kg/d = 20.9g/L
0.239L/d
Order TPN: D15% P21 g/L @10cc/h; Fat 0.83cc/h or 19.9cc/d
C. Your patient took a turn for the worse and is started on a dopamine drip in NS @ 1cc/h. You need to keep total fluid at 130cc/kg/day. As above, D15%, P2.5, F2. Please recalculate your TPN so it meets the above criteria.
As in part 1B above, first calculate
cc/hr to give TF of 130 cc/kg/d for a 2 kg baby:
wt x TF = cc/hr
24h/day
2kg x130cc/kg/day = 10.8cc/h
24h/day
Now let's calculate Fat in cc/day. Like before:
wt (kg) x F (g/kg/d) =
g/day
0.2g/cc (20% concentration)
2 kg x 2 g/kg/day = 20g/d
0.2
Divide 20 g/d by 24hrs to get cc/h:
20g/d ÷ 24h/d = 0.83cc/hr
Now Calculate the remaining total fluid for dextrose and protein by subtracting
the fat hourly rate and the dopamine drip hourly rate from the total hourly
rate:
Total cc/h = 10.8cc/h
Fat rate = 0.83cc/h
Dopamine drip=1cc/h
Rate of TPN is therefor: 10.8 - 0.83 - 1 = 8.97cc/h
Now calculate the protein concentration of the TPN to give a protein of
2.5 g/kg/d:
Now calculate the protein concentration of the TPN:
Protein (g/kg/day) = (L/d) x (g/L)
Wt (kg)
Like we said above, rearranging the above formula to figure out the concentration of TPN in g/L:
Wt (kg) x Protein (g/kg/day)
= (g/L)
(L/d)
changing some units again:
8.97cc/h x 24h/d = 215cc/d
215cc/d x 1L/1000cc = 0.215L/d
Now, using the above formula to figure out the g/L of protein in
the TPN:
2 kg x 2.5 g/kg/d = 23.25 g/L/d
0.215L/d
Order TPN: D15% P23 g/L @ 9cc/h; Fat 0.83cc/h or 19.9cc/d and Dopamine
running @ 1 cc/hr
D.
Your patient has been successfully weaned off of his dopamine drip
and is starting enteric feeds. He
will start 3cc Q3h of Enfamil w/Fe (PO/PG).
Assuming he is tolerating his feeds, how many kcal/kg/day does
he get from his PG feeds? How
many kcal/kg/day is he getting altogether (including TPN) adjusting TPN
rate when enteral feeds start?
The standard formula of Enfamil
w/Fe has 20kcal/oz. Our patient is getting 3cc Q3h which is:
3 cc x 8feeds/day =24cc/day from PG feeds.
24cc/d x 20kcal/30cc = 16kcal/d
divide by weight
16kcal/d ÷ 2kg = 8kcal/kg/day from the formula
To calculate the calories from the TPN:
First, a few things that you need
to know. There are 4 kcal/g of protein, 3.4 kcal/g of dextrose,
and 2.2 kcal/cc of 20% IL solution (the standard fat solution in the NBICU)
Protein = 2.5g/kg/day x 4kcal/g = 10 kcal/kg/day of protein
Fat = 0.83cc/h
0.83cc/h x 24h/day = 19.9 cc/day
Use formula of 2.2Kcal/cc in 20%IL:
19.9cc/day x 2.2kcal/cc = 43.8kcal/day
Divide by the weight:
43.8kcal/day ÷ 2kg = 21.9kcal/kg/day of fat
Dextrose: D15% @ 9cc/h
We said that the TF was 130 cc/kg/d, so a total of 260 cc's of fluid.
This was made up of 24 cc's of forula, 19.9 cc's (rounding to 20) of intralipids,
and 216 cc's of TPN.
D15% = 15g/100cc
15g/100cc x 216cc/day = 32.4g/day
32.4g/day x 3.4 kcal/g = 110.2kcal/day
Divide by the weight:
110.4kcal/day ÷ 2kg = 55.2 kcal/kg/day
of dextrose
Now add them up for your total kcal/kg/day:
Dextrose + Protein + Fat = Total calories
55.2 + 10 + 21.9 = ~87kcal/kg/day
Total calories is approximately 87kcal/kg/day
To calculate the total calories
including TPN just add PG kcal/kg/d with TPN kcal/kg/d
8kcal/kg/d + 87 kcal/kg/d = 95kcal/kg/d