The prediction of drop size from intravenous infusion controllers

In intravenous therapy, gravity-fed drip controllers regulate the flow of fluid in terms of drops per minute, though the total amount of fluid to be infused is specified in ml/h. To convert from one to the other it is regularly, erroneously, assumed that drop size is constant. The work described here investigates the relationship of drop size with respect to drip rate and fluid properties. The results are presented in an easy-to-use graphical form.