1. Review System
  2. Level Transducer
  3. Zero Transducer


Nurses may prime and connect the intraventricular drainage system in CCTC.  All CSF draining catheters (intraventricular; lumbar ICP) must be connected to the CodmanTM External Drainage System for safety.

This procedure refers to the measurement of intracranial pressure through an external ventricular drainage catheter (EVD) using a standard fluid filled pressure transducer.

For pressure monitoring using the Codman Microsensor(TM), refer to the link for the Setup of the Codman Microsensor System (TM):


Refer to the procedure for the Setup and Use of the Codman(TM) Intraventricular Drainage Unit in CCTC   for setup and positioning of the drainage collecting system.




Review Equipment

1.  Primed CodmanTM  External Drainage System that is zeroed according to Setup and Use of the Codman(TM) Intraventricular Drainage Unit in CCTC

2. Single pressure transducer circuit primed with normal saline
and connected to the patient stopcock stopcock closest to patient catheter (as per setup of drainage system)

3. Transducer pressure cable connected to bedside monitor and "ICP" selected as presure monitoring mode.  If ICP is greater than 20 mmHg, the scale will need to be increased.

4. "0" reference on Codman(TM) drainage unit panel has been leveled using a laser level (in CN cupboard)




Level Transducer

Tape the transdcuer to the back of the Codman(TM) drainage unit.

Position the transducer so that the stopcock that is located above the transducer is level with the "0" marking on the Codman(TM) drainage collection panel.

Note that drainage of CSF when the pressure in the cranial comparment exceeds the level (in cmH20) of the drainage collecting chamber. The catheter must also be patent and there must be CSF in the ventricle for drainage to occur.

The bedside monitor will display the ICP in mmHg.  Note on the Codman(TM) drainage panel equivalent pressures in cmH20 and mmHg.

For example, if the drain is set to a level of 10 cmH20, a drainage gradient occurs if the pressure in the head is greater than 10 cmH20 or 7.4 mmHg (equivalent bedside pressure).

level transducer


Turn laser level on while positioned in laser holder on Codman(TM) drainage collection system.  Adjust panel until the laser beam is directed into external auditory canal.



Taping the transducer into position will ensure that leveling of both the drainage collecting unit and pressure monitoring system can be accomplished each time the Codman(TM) drainage unit is re-leveled.


Leveling the drainage chamber ensures that CSF drainage will occur according to the prescribed pressure.

Leveling the transducer ensures accuracy of the displayed pressure on the bedside monitor.


Zero Transducer

  1. Perform hand hygiene

  2. Ensure stopcock located above transducer is level with "0" on Codman(TM) panel

  3. Remove the luer lock cap on the stopcock

  4. Turn the stopcock "off" toward the patient monitoring tubing (hard non-compliant tubing)

  5. Press "zero" on the bedside pressure monitoring module
  6. Confirm that the pressure waveform displayed is resting on the "zero" line of the pressure display
  7. Turn stopcock back to monitoring position
  8. Replace cap with non-vented luer lock cap
  9. Reconfirm level with each pressure measurement





Developed by:
Brenda Morgan
Created: November 1988

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

LHSCHealth Professionals

Last Updated July 24, 2013 | © 2007, LHSC, London Ontario Canada