System Overview

  1. Obtain Equipment
  2. Open Unit
  3. Prepare Panel
  4. Prime the Unit
  5. Position the Transducer
  6. Set Drainage Level
  7. Connect to Patient


Nurses may prime and connect the intraventricular drainage system in CCTC.  All CSF draining catheters (intraventricular; lumbar ICP) must be connected to the CodmanTMExternal Drainage System for safety. This setup is used for CSF drainage using either the CodmanTM Microsensor Ventricular Drainage Catheter or the standard fluid filled ventricular drainage system.

The CodmanTM  External Drainage System is a closed system for drainage and pressure monitoring of intraventricular catheters. An antimicrobial filter located at the top of the graduated collecting chamber and bottom of the drainage collecting bag prevents backward flow of fluid or bacteria. The unit must hang upright at all times. If it is placed flat in a horizontal position, the filter at the top of the drip chamber can become wet, preventing the system from draining properly.

The panel has a "0" reference point that must be positioned at the level of the catheter (in CCTC, the external auditory meatus is used as the reference point). The drip chamber buretrol is then adjusted up or down until it is at a level equal to the maximum desired intracranial pressure.  If the system is open to drainage, CSF will drain as soon as the pressure in the head exceeds the level set by the height of the drip chamber.

The CodmanTM drainage unit uses 3-way stopcocks. The stopcock can be opened in 3 directions simultaneously. The direction the prong points represents the "off" position.This system may be utilized for continuous pressure monitoring alone, continuous drainage alone or continuous drainage and pressure monitoring. To obtain an accurate pressure measurement, the stopcock should be turned "off" to drainage and "open" to the patient catheter and pressure monitoring system.  If pressure is measured when the drainage unit is open in all 3 directions, the pressure measured will be a reflection of the both the patient and drainage bag.


The Unit

The panel (left) must be positioned in an upright position, with the "0" reference point on the panel level with the patient's catheter. In CCTC, we use the external auditory meatus as the reference. The unit is designed to accommodate a customized lazer level (kept in CN drawer). This level is positioned to ensure that the laser beam is level with the "0" reference.

The drip chamber is then adjusted to a level equal to the maximum desired ICP (in cmH20 or mmHg).

The mounting panel stopcock is at the "0" level.

Codman Drain Labels


Codman Drain Top




4-Way Stopcock (left)

The Codman(TM) drainage system uses a 4-way stopcock. The catheter is off in the direction of the "prong" and open in all other directions.

When obtaining an ICP reading, the stopcock should be turned off to drainage to ensure that only the pressure in the head is being measured.




Obtain Equipment

1.  CodmanTM External Drainage System
2.  500 ml bag of 0.9% NaCl
3.  1 single transducer kit for arterial line*
4.  IV pole
5.  Laser level (in CN cupboard)or laser level pen designated for EDS lll located at the CN desk

6. PPE - non-sterile gloves

*Note: If you are setting up the drainage system for use with the Codman Microsensor EVD catheter, continue to prime the system with a single hemodynamic pressure set.

If using the Microsensor, do not connect the hemodynamic transducer to pressure monitoring; the Codman Express is the preferred method for monitoring.

If you are using a conventional fluid filled ventricular catheter (not the Microsensor), the transducer on the hemodynamic set will also provide pressure monitoring.

For pressure monitoring see the following procedures:


Fluid Filled Circuit



The use of an infusion set for priming provides a closed system flush in the event that you need to flush blood or tissue out of the tubing DISTAL to the stopcock (never flush in the direction of the patient catheter). The roller clamp to the flush device is always left OFF.

Pressure tubing provides an additional safeguard against accidental flushing. Even if the roller clamp was inadvertently left on, the flush device of the pressure tubing will only allow flow if the infusion solution is pressurized or the flush device pigtail is activated.



Open Unit

Open package with CodmanTM External Drainage Unit, being careful not to drop extension pieces out; extension pieces are loosely connected in package.


The connections are loosely attached to facilitate gas sterilization.


Prepare Panel

  1. Perform hand hygiene.

  2. Replace the vented white cap located on the mounting panel stopcock (at the "0" reference mark) with a dead-end luer lock cap (provided in kit).

  3. Turn the mounting panel stopcock with the flat side (off) toward the cap.

    Always leave the mounting panel stopcock in this position; if you wish to turn the stopcock open or closed to drainage, use the stopcock closest to the patients head.


This opens the system between the drainage tubing and drip chamber in preparation for flushing. 

By only adjusting one stopcock during use, the risk of accidental closure/opening of the system is reduced.


Prime the Unit

  1. Hang a bag of normal saline. 

  2. Using the normal saline, prime the pressure tubing as per setting up a hemodynamic system.

  3. Remove the extension piece at the distal end of the pressure tubing. 

  4. Remove the cap from the stopcock located closest to the patient end of the drainage tubing (this will be referred to as the "patient stopcock").

  5. Connect the distal end of the pressure tubing to the stopcock where the cap has been removed.  Be careful not to contaminate the connections.

  6. Turn the patient stopcock with flat side (off) towards the patient connection end of the circuit.

  7. Pull the flush device until the all air bubbles have been eliminated and fluid drips readily into the drip chamber.

  8. Turn the patient stopcock with the flat side (off) towards the drip chamber.

  9. Remove the unvented cap at the tip of the drainage tubing, being careful not to contaminate the end.

  10. Flush the circuit until all air has been expelled between the patient stopcock and end of drainage tubing. 

  11. Replace the unvented cap at the end of tubing and tighten. 

  12. Turn the patient stopcock to a 45 degree angle from the tip.




Heparin is not used due to risk of intracranial bleeding.  The system is not pressurized to avoid introducing fluid into the brain.

Once primed, the pressure tubing will be used to measure intracranial pressure.

The extension tubing is an unnecessary access point with ICP monitoring systems.

The pressure tubing is connected to the stopcock closest to the patient to minimize the length of tubing that the pressure wave must travel. CSF drainage often contains blood and debris; adding the flush system at the patient stopcock allows the circuit to be flushed between the patient stopcock and the drip chamber as required to maintain patency and pressure transmission.


The entire circuit must be primed to facilitate drainage. Be careful to maintain aseptic technique; CSF contains glucose which promotes bacterial growth that can cause meningitis.

Tightening maintains sterility and prevents loss of priming fluid. A 45 degree angle on any stopcock ensures that it is "off" in all directions.


For pressure monitoring using fluid filled system, see Procedure for Pressure Monitoring with Fluid Filled System




Set the Drainage Level

  1. Obtain an order for the level of the drainage chamber. 

  2. Loosen the buretrol adjustment screw and move the drip chamber until the small arrow is aligned with the desired height.  

  3. Tighten the screw to secure the buretrol position.

NOTE: A typical order is "10 cmH20" above the head. The right hand column of numbers (with red writing) is in cmH20.  The column to the left is in mmHg (orders for drip chamber placement are usually in cmH20 - check with the physician to confirm the correct level). 

In the example of "10 cmH20", the system is correctly placed if the "0" reference point is level with the patient's external auditory meatus and the small arrow is aligned at the 10 cmH20 marking.  


If the "0" reference is level with the patient's catheter, a drainage level of 10 cmH20 above the head provides automatic "venting" of fluid from the head the moment the intracranial pressure rises above 10 cmH20.  If the "0" reference and the drip chamber are both positioned level with the catheter, drainage would occur the moment the pressure in the head > 0.  Normal ICP is < 10 mmHg. If the drainage is set at a level below normal ICP, drainage will occur even if the ICP is not elevated.

Weaning of the drainage system can be done by raising the level of the drainage unit. Drainage will only occur if the pressure exceeds this higher pressure. Intermittent drainage may also be initiated, where pressure is monitored and drainage only opened if the pressure exceeds a specific level.

Both the patient and panel stopcocks must be open between the patient's catheter and the drainage chamber for drainage to occur. When the system is left continuously open to drain and the drainage chamber is positioned to initiate drainage at a set level, ICP can be maintained at a more consistent level. 

Note that the bedside monitor measures pressure in mmHg; 10 cmH20 is the same as 7.4 mmHg.  Thus, a properly positioned unit with the drip chamber at 10 cmH20 will drain if:

  • the stopcocks are open between the patient's catheter and the drip chamber

  • the pressure in the head exceeds 10 cmH20 (or exceeds 7.4 mmHg on the bedside monitor).

  • the catheter/circuit is patent (e.g. free of clot or debris)

  • there is fluid in the ventricle available to drain (if the pressure is high due to brain swelling but the ventricles are collapsed, there won't be any CSF available to drain)

If the circuit fails to drain despite a pressure on the monitor that is > than the level of the drainage chamber, patency can be assessed by lowering the entire drainage unit to below the head.

Notify Neurosurgery if the unit fails to drain in the presence of an elevated pressure despite troubleshooting efforts.


Connect to Patient

  1. Following insertion of the intraventricular catheter, the physician must insert the small white connector into the silicone intraventricular catheter.

  2. The connector has a "nipple" end that is inserted inside the catheter tip. This nipple has a luer lock connection for attachment to the CodmanTM unit.

  3. Connectors are provided in both the intraventricular catheter kit and the CodmanTM.


Developed by:
Brenda Morgan

Initial Procedure: November 1988

Last Update:March 29, 2010, July 24, 2013.