In medicine, infusion therapy deals with all aspects of fluid and medication infusion, via intravenous or subcutaneous application. A special infusion pump can be used for this purpose.A fenestrated catheter is most frequently inserted into the localized area to be treated. In medicine, infusion therapy deals with all aspects of fluid and medication infusion, via intravenous or subcutaneous application. A special infusion pump can be used for this purpose.A fenestrated catheter is most frequently inserted into the localized area to be treated.