Calculating osmolarities of peripheral infusions to avoid thrombophlebitis

When prescribing medications for patients it is not unusual to need to consider, and balance, multiple competing requirements and limitations. Within the context of critically unwell children, there may be the need to provide fluids and energy intravenously, but certain medical conditions may impose limits that need to be adhered to.

Particularly with children being treated for congenital cardiac abnormalities there may be the need to restrict the amount of fluid that can be administered to preserve cardiac function by controlling factors such as load on the heart. For children unable to receive nutrition orally it is often the case that the limited fluid allowance is the only medium in which sources of energy can be provided, though excessive energy provision can lead to hypercapnia, hyperventilation, or lipaemia (Mesotten et al, 2018).

In the case we will consider here we are looking after an unwell child that is nil-by-mouth and fluid restricted. The consultant has decided to limit fluid provision to 60 ml/kg/day. Because they are unwell energy will be provided solely from peripheral glucose infusions, with a target of 6-8 mg/kg/minute of glucose to provide sufficient, but not excessive, carbohydrate-based energy (Mesotten, 2018).