A drip chamber is a device used to allow gas (such as air) to rise out from a fluid so that it is not passed downstream. They are commonly employed in delivery systems of intravenous therapy

Intravenous therapy

Intravenous therapy or IV therapy is the infusion of liquid substances directly into a vein. The word intravenous simply means "within a vein". Therapies administered intravenously are often called specialty pharmaceuticals...

 and act to prevent air embolism

Air embolism

An air embolism, or more generally gas embolism, is a pathological condition caused by gas bubbles in a vascular system. The most common context is a human body, in which case it refers to gas bubbles in the bloodstream...

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The use of a drip chamber also allows an estimate of the rate at which fluid is administered. For a fluid of a given viscosity

Viscosity

Viscosity is a measure of the resistance of a fluid which is being deformed by either shear or tensile stress. In everyday terms , viscosity is "thickness" or "internal friction". Thus, water is "thin", having a lower viscosity, while honey is "thick", having a higher viscosity...

, drips from a hole of known size will be of identical volume and the number of drips in a minute can be counted. In this instance the rate of flow is usually controlled by a clamp on the infusion tubing; this affects the resistance to flow. However, other sources of resistance (such as whether the vein is kinked or compressed by the patients position) cannot be so directly controlled and a change in position may change the rate of flow leading to inadvertently rapid or slow infusion. Where this might be problematic an infusion pump

Infusion pump

An infusion pump infuses fluids, medication or nutrients into a patient's circulatory system. It is generally used intravenously, although subcutaneous, arterial and epidural infusions are occasionally used....

can be used which gives a more accurate measurement of flow rate.