ABSTRACT
Intravenous constant rate infusions begin with an intravenous loading dose of the same analgesic to be infused. The technique requires the placement of an indwelling intravenous catheter. The infusion rate can be calculated using several different methods but a method known as dimensional analysis is more intuitive and provides insight into the cause of mistakes in calculation. If analgesic drugs are to be administered with maintenance fluids, the length of infusion will be determined by the volume of maintenance fluid in the bag and rate of fluid administration. If the analgesic drug delivery rate is to be changed, people should be careful not to exceed safe rates of maintenance fluid administration. It helps to mix one bag of fluids with the maximum desired concentration of analgesic drug added, and then dilute it to a lower concentration by piggybacking it onto a second unspiked bag of maintenance fluid.
