Enteral tube feedings are often given in a concentration less than full strength or 100%.  It is often advisable to administer the feeding with some amount of dilution to assess the client's ability to tolerate the feeding.  The dilution will be determined by the physician and will be ordered in a fraction - 1/4 strength - or in a percentage 50% strength.  Enteral feeding formulas usually come full strength in a can and dilution must be calculated and prepared by the nurse.

Formulas for Dilutions

CV= Concentration Volume is the amount of full strength formula used in the feeding.

TV= Total Volume is the amount of formula plus the water used for dilution.

DS= Desired Strength of the enteral tube feeding (may be a fraction or a percent).

1.  CV  = DS              2.  TV - CV = Water added  
     TV                        3.  DS x TV = CV

Example:

Order: 1/2 strength Pulmocare via G-tube at 60 cc/hr
Available: Pulmocare 240 mL can (full strength)
How much water should be added to each can to prepare the desired concentration?

Using the formula above:  240 cc (CV)= 1/2  strength (DS)
                                             TV    
                            or

240 ÷ 1/2 = TV = 240 X 2/1 = 480 (TV)
480 - 240 (CV) = 240 mL (amount of water to add)

Enteral feeding calculations may also take into account caloric intake, which is always printed as calories per ounce on the can.

Example:

A client is to receive 2000 calories per day of Jevity feeding.  A can of Jevity contains 250 calories per 8 oz.
How many mL of Jevity does the client need to consume daily?

Using Dimensional Analysis:

Test your knowledge with Quiz 9

Home Page