FORMULA FOR CALCULATION

OF CONSTANT RATE

INFUSIONS



This may be useful when using dobutamine, sodium nitroprusside and lignocaine. Also see Chapter 21, Table 21.2 (CR1 for lignocaine), and Table 21.3 (CR1 for dobutamine), and Macintire (1995).


  1. To make up an infusion that will last for 6 hours: choose the volume of fluid required for 6 hours,
    and set the drip rate.

Body weight (kg) x dose (u/kg/min) x 0.36
= total dose in mg to be added to fluid for infusion to be given over 6 hours.


  1. The following formula is more versatile and allows the clinician to work out any combination. Quantity of drug (mg) to be added to the fluids for infusion =

Dose rate of drug (ug/kg/min) x body weight (kg) x volume of fluid (ml)

delivery rate (ml/mm) x 1000



or


Delivery rate (ml/mm) of the infusion =

Dose rate of drug (ug/kg/min) x body weight (kg) x volume of fluid (ml)

quantity of drug (mg) added to fluids x 1000