EVD Set Glossary: Terms Used on External Drainage Sets

A glossary of EVD set terms: measuring scale, drip chamber, drainage bag, hydrophobic filter, three-way connector and more, as used on DESU EVD-010 and EVD-020.

An EVD set is the complete system for draining cerebrospinal fluid (CSF) outside the body: a catheter, a connection line, a measuring scale, a drip chamber and a collection bag. This glossary defines those terms as they are used on DESU EVD sets, the EVD-010 Series and the EVD-020 Series.

Key takeaways

An EVD set combines a catheter with a drainage system: line, scale, drip chamber, bag and filter.
“Set”, “kit” and “system” are used interchangeably; DESU uses “system” and “series”.
The scale is the ruler; the drainage level is the setting read on it, as ordered by the clinical team.
EVD-010 and EVD-020 have the same drainage components; EVD-020 can be used with a ventricular or a lumbar catheter.

Entries are grouped by where the part sits in the set. For a wider list of catheter terms, see the neurosurgical catheter glossary. Clinical practice follows the instructions for use (IFU) and unit protocol.

What do “EVD”, “set” and “system” mean?

External ventricular drainage (EVD): temporary drainage of CSF from a cerebral ventricle to a collection system outside the body.
Ventriculostomy: the procedure that places a catheter in a ventricle. The word is often used loosely for the drain itself.
External lumbar drainage: the same idea, with CSF drained from the lumbar space through a lumbar catheter.
EVD set, kit or system: three names for the same thing in everyday use. DESU speaks of an external drainage system offered as a series.
Drainage system: everything downstream of the catheter, from the connection line to the bag.
Series: a product family. EVD-010 combines a 31 cm ventricular catheter with a complete drainage system. EVD-020 is an advanced external drainage system, used with a ventricular or a lumbar catheter.
Standard and antibiotic-impregnated: the two catheter options. In the impregnated version the antibiotic is impregnated into the material and released in a controlled manner over 28 days. Impregnated catheters are orange, standard ones white.

Which terms describe the catheter end of the set?

Ventricular catheter: the catheter that carries CSF from the ventricular system to the drainage system. In EVD-010 it has a 1.5 mm inner diameter, a 3.0 mm outer diameter and a length of 31 cm.
Lumbar catheter: the catheter used for drainage from the lumbar space. The lumbar drainage catheter kit has an 80 cm catheter with a 0.8 mm inner and 1.6 mm outer diameter.
Stylet: an accessory that supports guided, controlled advancement of the catheter during placement.
Angled trocar: an application accessory that supports guidance and placement of the catheter.
Tuohy needle: the needle used to reach the lumbar space. It appears in lumbar drainage kits.
Guidewire: a thin wire that helps advance and guide a lumbar catheter in a controlled manner.
Fixation tab: a part that helps stabilise the catheter in position after placement.
Luer Lock connector: a threaded connection that forms the link between the catheter and the drainage system.
Distal cap: the cap supplied with the Luer Lock connector.

Which terms describe pressure and measurement?

Measuring scale: the graduated scale that supports CSF pressure tracking and adjustment of the drainage level. On DESU sets it is 30 cm long, with mmHg and cmH₂O markings.
cmH₂O and mmHg: the two units on the scale. One mmHg is about 1.36 cmH₂O; our EVD scale conversion guide explains how to read both.
Intracranial pressure (ICP): the pressure inside the skull. In a ventricular drain, CSF pressure gives a way of following it.
Zero point or reference level: the point on the patient that the scale is aligned with, set by unit protocol. The ear canal is a common external landmark.
Levelling: aligning the zero of the scale with that reference point, and repeating it when the patient’s position changes.
Drainage level: the height set on the scale, as ordered by the clinical team. CSF drains when pressure exceeds this level.
Overdrainage and underdrainage: too much or too little CSF leaving the ventricles or lumbar space compared with what the clinical team intends.

Which terms describe collecting CSF?

Drip chamber: the 150 ml chamber that supports visual monitoring of drainage flow and passes the fluid on to the bag.
Drainage bag: the 800 ml bag that collects CSF. It is clear, so the fluid level can be followed, and it can also be supplied separately in packs of 1, 5 or 10 (codes ENDS-B1, ENDS-B5 and ENDS-B10), sterile and single-use.
Air filter: the filter integrated into the drainage bag.
Hydrophobic filter: a filter that repels liquid. Filters of this type let air pass and keep fluid back, so they need to stay dry to work properly. On DESU sets it is a core component.
Drainage output: the volume of CSF collected over a stated period, as recorded by the unit.

Which terms describe the line and its connections?

Reinforced connection line: the 60 cm line that links the components of the drainage system.
Locking mechanism: the feature on that line that secures the connection.
Three-way connector: a connector with three ports, also known as a three-way stopcock, which is turned to direct or stop flow. Each DESU set has two.
Clamping: temporarily stopping drainage, for example before moving a patient, as ordered and according to unit protocol.
Closed system: a drainage path kept sealed from the outside. On EVD-020, the hydrophobic filter and the two three-way connectors are the closed-system features.
Small-bore connector: the general family of fittings, such as Luer connections, that the EN ISO 80369 standards address.

Which EVD terms are most often confused?

Terms	The difference
EVD and shunt	An EVD drains to the outside and is temporary; a shunt is implanted and drains to another body cavity.
Measuring scale and drainage level	The scale is the ruler; the level is the setting read on it.
Drip chamber and drainage bag	The chamber shows flow and passes fluid on; the bag holds the collected volume.
Stylet and trocar	The stylet sits inside the catheter and supports its advancement; the trocar is a separate rigid tool that supports guidance and placement.
Series and code	A series is the family; a code such as ENDS-AC-010 is one exact configuration.

Talk to a DESU product specialist

If you need a term explained for a training session or a component list for a tender, DESU’s product specialists can help. Write to sales@desu.tr, use the contact page, or request a quote.

Frequently asked questions

Is a ventriculostomy the same as an EVD?

They are closely linked. Ventriculostomy is the procedure that creates access to the ventricle, and the EVD is the drainage system connected to it. In everyday speech the two words are often swapped.

Is an EVD set the same as an ICP monitor?

Not exactly. The 30 cm scale on a DESU EVD set supports CSF pressure tracking in mmHg and cmH₂O. EVD-010 and EVD-020 do not include an electronic transducer, so tell us if your unit needs one connected.

How do the set codes show the catheter type?

ENDS-C-010 and ENDS-C-020 are the standard ventricular catheter versions, and ENDS-AC-010 and ENDS-AC-020 are the antibiotic-impregnated ones. LCK-ENDS-020 and LACK-ENDS-020 are the EVD-020 lumbar versions.

Related standards

ISO 13485: Medical devices — Quality management systems
EN ISO 80369 series: Small-bore connectors for liquids and gases in healthcare applications