Appendices

1. Paediatric Intravenous Fluids

2. Increasing the glucose concentration of IV fluid bags

3. Parenteral nutrition

 

1. Paediatric Intravenous Fluids

Consult local protocols and the Standards for Paediatric Intravenous Fluids: NSW Health for detailed information.

 

Table 1. Intravenous Fluid Bag Composition

 

	IV Fluid composition
IV Fluid	Calcium     mmol/L	Chloride      mmol/L	Glucose       g/L	Lactate    mmol/L	Potassium       mmol/L	Sodium      mmol/L	Osmolarity                        mOsm/L	pH
Glucose 5% (G5W)			50				278 (Isotonic)	3.5–6.5
Glucose 10% (G10W)			100				556 (Hypertonic)	3.5–6.5
Glucose 50% (G50W)			500				2778 (Highly hypertonic)*	3.2–6.5
Hartmann’s (Compound Sodium Lactate) (LR)	1.8–2	112		28–29	5–5.4	131	280 (Isotonic)	5–7
Plasma-Lyte 148 (P148) Also contains: 1.5 mmol/L magnesium 27 mmol/L acetate                     23 mmol/L gluconate		98			5	140	298 (Isotonic)	6.5–8
Plasma-Lyte 148 and glucose 5% (P148G) Also contains: 1.5 mmol/L magnesium 27 mmol/L acetate                     23 mmol/L gluconate		98	50		5	140	584 (mOsm/kg) (Hypertonic)	4–6
Ringer’s (R)	2.2	112			4	147	276 (Isotonic)	5–7.5
Sodium chloride 0.45% (½NS)		77				77	154 (Hypotonic)	4–7
Sodium chloride 0.9% (NS)		154				154	308 (Isotonic)	4–7
Sodium chloride 0.9% and glucose 5% (G5/NS)		154	50			154	585 (Hypertonic)	3.5–5.5
Sodium chloride 0.18% and glucose 4% (G4/NS0.18)		30	40			30	290 (Isotonic)	3.5–6.5

*Caution: Highly hypertonic solutions may cause vein damage on administration.

References

1. Product information. Available from www.tga.gov.au. Accessed 10/03/2021.
2. OneCall Medical Information Service. Plasmalyte (multiple electrolytes injection, USP). Summary of available drug compatibility information. Available at: http://chw.schn.health.nsw.gov.au/ou/pharmacy/resources/medicine_information/injectable_medicines/plasmalyte_compatibility_summary.pdf. Accessed 10 March 2021.

In accordance with NSW Health Policy directive, Children and Adolescents - Guidelines for Care in Acute Care Settings PD2010_034, Section 3.3.10: "Paediatric infusions sets with an inline burette must be used for all children requiring intravenous therapy. An infusion pump should be used in all children".

All IV fluid bags must be changed every 24 hours.

The British Pharmacopoeia (BP) requires that any container for injection be filled with an excess volume sufficient to permit withdrawal and administration of the labelled volume. Table 2 provides guidelines on the overfill volume and the maximum volume of medicine that can be safely added to the IV fluid bag without adding additional pressure to the bag.

• Medicines should NEVER be added to hanging IV fluid containers.
• IV bags containing added medicines should be shaken well before inserting the administration set.
• Administration sets should be inserted BEFORE hanging the bag on the drip stand.

 

Table 2. Intravenous Fluid Bag volumes

 

Volume	Average volume including BP overage	Overfill volume range	Maximum volume which may be added
50 mL	57 mL	55–60 mL	140 mL (same dimensions as 100 mL bag)
100 mL	108 mL	105–110 mL	90 mL
250 mL	265 mL	260–270 mL	60 mL
500 mL	533 mL	525–540 mL	100 mL
1000 mL	1035 mL	1030–1040 mL	100 mL

The average overage volume may differ between the viaflex and viaflo IV fluid bags, particularly the 500 mL size (viaflex 545 mL and viaflo 530 mL). These calculations are based on the BP specifications.

 

2. Increasing the glucose concentration of IV fluid bags

Some resources refer to glucose as dextrose as they are the same sugar. In the PIMH reference is to glucose.

There are variable practices with regards to the method to change the glucose concentration of an existing IV fluid bag containing glucose, sodium chloride or a combination of glucose and sodium chloride. Some methods consider the overage and withdrawing of the fluid before addition of 50% glucose solution, while other methods limits accessing of the bags and calculates an approximate glucose concentration. Both methods have been described:

2.1 Formulas considering the IV Fluid bag overage volume

2.2 Formulas not considering the IV Fluid bag overage volume and withdrawal of fluid

It is important to ensure consistency in the preparation process for an individual patient to avoid variations in concentration and the amount of  glucose and sodium delivered. 

These formulas also apply for IV fluid bags containing sodium chloride.

 

2.1 Formulas considering the IV Fluid bag overage volume

Note: These formulas apply to any size IV fluid bag.

The maximum volume that can be added to a 500 mL and 1000 mL bag  is 100 mL.

To avoid unnecessary access of the IV fluid bag a combination of formula 1 (volume ≤100 mL to be added)  and  formula 2  (volume >100 mL to be added) is used

 in Table 1 (500 mL bag)  and Table 2 (1000 mL  bag) below.

 

C_L = the concentration of the initial IV fluid (lowest concentration)

V_L = the volume of the lowest concentration initial IV fluid 

C_H = the concentration of the 50% glucose (highest concentration)

V_H = the volume of the 50% glucose stock solution to add 

C_F = the concentration of the final desired glucose concentration

V_F = the desired final total volume = V_L  +   V_H 

The concentrations C_L, C_H, and C_F all must be in the same units.

 

 

2.1.1 Formula 1 for calculation of additional glucose 50% to a IV fluid Bag where the volume to add is ≤100 mL and no withdrawal of fluid is required

 

CL  VL    +   CH  VH    =     CF  VF

 

Worked example

To calculate the amount of glucose 50% solution that needs to be added to a  500 mL Glucose 2.5% bag (533 mL incuding overage) to make a Glucose 7.5 % bag.

C_L = the concentration of the initial IV fluid (lowest concentration) = 2.5%

V_L = the volume of the lowest concentration initial IV fluid  = 533 mL

V_F = the desired final total volume =  533 mL +  V_H

C_H = the concentration of the 50 % glucose (highest concentration) = 50%

V_H = the volume of the 50 % glucose stock solution to add 

C_F = the concentration of the final desired glucose concentration = 7.5 %

 

(2.5% x  533 mL)    +   50%  V_H      =     7.5% (533 mL  +   V_H)

                    50%V_H  -  7.5%V_H     =     39997.5 mL - 1332.5  mL

                                  42.5 V_H        =     2665

                                          V_H        =     2665/42.5

                                                      =     63 mL

 

  2.1.2  *Formula 2 for calculation of additional glucose 50% to a IV fluid Bag where the volume to add is >100 mL and withdrawal of fluid is required

 

VH      =          [CF - CL  ]   x   vF                          ----------------                          [CH - CL  ]

 

Worked example

To calculate the amount of glucose 50% solution that needs to be added to a 1000 mL Glucose 5% bag (1035 mL including overage) to make a Glucose 10 % bag.

C_L = the concentration of the initial IV fluid (lowest concentration) = 5%

V_F = the desired final total volume = 1035 mL

C_H = the concentration of the 50 % glucose (highest concentration) = 50%

V_H = the volume of the 50 % glucose stock solution to add which is also equal to the volume of the initial (low concentration) glucose that must be withdrawn from the bag

C_F = the concentration of the final desired glucose concentration = 10 %

 

V_H        =         [10% - 5%  ]   x   1035 mL

                         _{----------------}

                         [50% - 5%  ]

         

         =          115 mL

 

Table 1. Preparation of different Glucose concentrations adding glucose 50% (G50W) solution to a 500 mL IV bag

• The 500 mL IV fluid bag has a total average volume of 533 mL including overage which has been considered in the calculations below.
• Due to the range of the bag overage, volumes of 50% Glucose to be added to the bag are rounded off for convenience.

		Required Glucose Concentration for a 500 mL bag
		5%	7.5%	10%	12.5%
Current Glucose Concentration in a 500 mL bag	2.5%	30 mL	63 mL	100 mL	*112 mL (first withdraw 112 mL from bag)
	3.75%	15 mL	47 mL	83 mL	*101 mL (first withdraw 101 mL from bag)
	5%	-	31 mL	67 mL	*89 mL (first withdraw 89 mL from bag)
	10%	-	-	-	36 mL

* Calculated using the formula 2 where fluid needs to be first withdrawn

 

Table 2. Preparation of different Glucose concentrations adding glucose 50% solution to a 1000 mL IV bag

• The 1000 mL bag has a total average volume of 1035 mL including overage which has been considered in the calculations below.
• Due to the range of the  bag overage, volumes of 50% Glucose to be added to the bag are rounded off for convenience.

		Required Glucose Concentration for a 1000 mL bag
		5%	7.5%	10%	12.5%
Current Glucose Concentration for a 1000 mL bag	2.5%	58 mL	*109 mL (first withdraw 109 mL from bag)	*163 mL (first withdraw 163 mL from bag)	*218 mL (first withdraw 218 mL from bag)
	3.75%	29 mL	91 mL	*140 mL (first withdraw 140 mL from bag)	*196 mL (first withdraw 196 mL from bag)
	5%		61 mL	*115 mL (first withdraw 115 mL from bag)	*173 mL (first withdraw 173 mL from bag)
	10%				69  mL

* Calculated using the formula 2 where fluid needs to be first withdrawn

 

2.2 Formulas not considering the IV Fluid bag overage volume and withdrawal of fluid

2.2.1 Formula to calculate the volume of 50% glucose to add to 500 mL fluid bag to change the glucose concentration

This formula does not consider the  bag overage and  first withdrawing  of solution from the low concentration bag. This is to limit the number of times that the IV fluid bag is accessed.

When adding glucose to solutions, dilution of base solution will occur, therefore all final concentrations of sodium chloride and glucose are approximate.

 

Volume of 50% glucose (mL) to add to  500 mL  IV bag]  = [% glucose required   -  % glucose in stock IV fluid] x 10

 

• Formula is only suitable where volume of glucose 50 % to be added is less than or equal to 100 mL  (maximum volume which may be added to a 500 mL bag).
• Volumes >100 mL glucose 50 % requires IV fluid to be withdrawn from bag to ensure that the maximum bag volume is not exceeded. This will result in an approximate glucose concentration.

To calculate the amount of glucose 50% solution that needs to be added to a  500 mL Glucose 5% bag to make a Glucose 10 % bag.

Volume of 50% glucose (mL) to add to 500 mL  IV bag]  = [10% glucose required  -  5 % glucose in stock IV fluid] x 10

                                                                                                 = 50 mL

Current Glucose Concentration	Required Glucose Concentration for a 500 mL bag
	10%
5%	Add 50 mL

 

 

2.2.2 Formula to calculate the volume of 50% glucose to add to 1000 mL (1 L) fluid bag to change the glucose concentration

This formula does not consider the bag overage and  first withdrawing  of solution from the low concentration bag. This is to limit the number of times that the IV fluid bag is accessed.

When adding glucose to solutions, dilution of base solution will occur, therefore all final concentrations of sodium chloride and glucose are approximate.

 

Volume of 50% glucose (mL) to add to 1000 mL  IV bag]  = [% glucose required   -  % glucose in stock IV fluid] x 20

 

• Formula is only suitable where volume of glucose 50 % to be added is less than or equal to 100 mL  (maximum volume which may be added to a 1000 mL bag).
• Volumes >100 mL glucose 50 % requires IV fluid to be withdrawn from bag to ensure that the maximum bag volume is not exceeded. This will result in an approximate glucose concentration.

 To calculate the amount of glucose 50% solution that needs to be added to a 1000 mL Glucose 5% bag to make a Glucose 10% bag.

Volume of 50% glucose (mL) to add to 1000 mL  IV bag]  = [10% glucose required   -  5 % glucose in stock IV fluid] x 20

                                                                                                 = 100 mL

Current Glucose Concentration	Required Glucose Concentration for a 1000 mL bag
	10%
5%	Add 100 mL

 

References

1.Savva, Michalakis. Pharmaceutical Calculations: A Conceptual Approach. 1st ed., Springer International Publishing AG, 2019.

2. Lesson 3: Calculations used when compounding medications  Available at http://courses.washington.edu/pharm309/calculations/Lesson3.pdf, accessed 18 March 2021.

 

3. Parenteral nutrition

Consult SCHN Parenteral Nutrition Practice Guideline

Table 1. Composition of the standard parenteral nutrition solution

	Infants <3 months of age			Children >3 months of age
Parenteral Nutrition solution	Preterm	NPVL	NCVL	S2-10	S4-20	S4-25
Amino acid (%)	3	2	2.3	2	4	4
Glucose (%)	10	10	12	10	20	25
Sodium (mmol/100 mL)	3.3	2.5	2.5	4	4	4.5
Potassium (mmol/100 mL)	2.2	2	2	2.4	2.4	4
Calcium (mmol/100 mL)	1.2	0.7	1.2	1	1	0.5
Magnesium (mmol/100 mL)	0.15	0.1	0.15	0.4	0.5	0.5
Phosphate (mmol/100 mL)	1	0.7	1	0.9	0.9	1
Chloride (mmol/100 mL)	1.35	2.8	2.6	3.9	4.4	6
Zinc (mg/100 mL)	0.326	0.19	0.19	-	-	-
Heparin (units/100 mL)	50	50	50	-	-	-
Total kcal (kcal/mL)	0.5	0.46	0.55	0.46	0.92	1.11
Non-nitrogen kcal (kcal/mL)	0.38	0.38	0.45	0.38	0.76	0.95