The Codman Microsensor(TM) measures intracranial pressure via a strain guage microchip located at the tip of the catheter. Pressure is reflected as an electrical voltage that is transmitted to the proximal end of the catheter through nylon encapsulated copper wires. The proximal end of the catheter is connected to the Codman Express(TM) monitor, which displays the intracranial pressure measurement (ICP).


A cable connected between the Codman Express(TM) and the bedside monitor is required to produces an intracranial pressure waveform on the Datex monitor.


Note, the pressure is actually measured by the Codman Express(TM); the pressure on the bedside monitor is a copy of the Codman Express(TM) reading.

There are two different types of Codman Microsensor(TM) catheters in use in the CCTC:

  • Intraparenchymal Catheter:

    The intraparenchymal catheter is a thin catheter inserted into brain tissue (parenchyma), just below the level of the dura. It can only be used for pressure monitoring. It does not contain any drainage or fluid filled lumen. Pressure at the tip (in the brain tissue) is measured using the Codman Microsensor(TM).


  • Codman Microsensor(TM) External Ventricular Drainage Catheter:

    This catheter is similar to a conventional fluid filled ventricular drainage catheter. It is inserted into the ventricle, has a drainage lumen to allow removal of CSF, and could be connected to a fluid filled pressure monitoring system to measure intraventricular pressure.

    This catheter differs from the standard fluid filled drainage catheter by having a Codman Microsensor(TM) located at the catheter tip. This allows pressure to be measured at the tip of the ventricular catheter by the same strain gauge technology as the intraparenchymal model. Pressure measurement with the Microsensor(TM) is not influenced by patency of the fluid pathway. While technically, you could connect this catheter to conventional fluid filled pressure monitoring if you did not have an available Codman Express(TM), the preferred pressure monitoring is always using the Codman Express(TM).

    Because this catheter is both a pressure monitoring device and an intraventricular drainage catheter, the catheter will also need to be connected to an external ventricular drainage unit (EDS III ) as well as the Codman Express monitor.

    This procedure provides instruction for set-up, zeroing and calibration of the intraparenchymal or the external ventricular Codman Microsensor catheters. If you are setting up an intravententricular device, you will also need to setup an external ventricular drainage unit. Click here to access the procedure for setting up an external ventricular drainage unit (EDS III )


  • Personal protective equipment (PPE)
  • Sterile towels
  • Sterile ventricular drain tray including disposable drill
  • Hair clippers
  • Microsensor ICP transducer (ICP catheter)
  • Codman ICP Express monitor
  • Cable to connect and interface Datex monitor to ICP Express
  • Sterile occlusive dressing (Tegaderm)
  • Topical anesthetic
  • Suture
  • IV pole

  1. Prepare family
  2. Prepare Equipment
  3. Connect Microsensor
  4. Plug in Monitor Cable
  5. Activate Machine
  6. Zero Datex
  7. Calibrate
  8. Connect Cables
  9. Prepare Catheter

  1. Zero Express
  2. Access Menu
  3. Assist with Catheter Insertion
  4. Apply Dressing
  5. Document
  6. Discard Medical Waste
  7. Transport to CT
  8. Reconnection of Codman Express and zeroing of Datex monitor




Prepare Family

Explain procedure to family and prepare them for additional equipment and patient appearance.



Prepare Equipment

  • Gather listed equipment.
  • Ensure electrical cord connected and plugged in to red electrical outlet at patient’s bedside.
  • Secure Codman ICP Express monitor to separate IV pole and position at head of bed.
  • Hand Hygiene and obtain personal protective equipement.


ICP Express monitor has no battery power. Red outlets are connected to auxiliary electrical power in case of power failure.

Positioning of set at head of bed prevents accidental dislodgment of catheter.


Connect Microsensor  

Connect the Codman Microsensor  Transducer cable to the front of the monitor. Ensure the white lines are aligned and the cable is snapped into place.


Plug in Cable


Plug In Monitor Cable

Plug the monitor cable into the 9 pin connector at the back of the ICP Express monitor. Secure the 2 locking screws on the cable. Connect the cable to the appropriate pressure module on the Datex monitor (P3).


Allows for information (value and waveform) from ICP Express monitor to be displayed on bedside monitor.

Plug In Cable


Activate Machine

Turn on ICP Express by pressing “On/Off” key located at front of monitor. An audible tone will be heard. The monitor will conduct self-diagnostic tests.

Turn On


To ensure equipment is functioning properly. If any errors are detected during self-test period, the monitor will display an error message. Unplug monitor and send to Biomed for service.



To zero the Datex monitor, follow these steps:

  • Press the Menu/Enter button
  • If the Codman Express does not immediately prompt you with a message "Proceed to zero monitor", press the white "0" (zero monitor) button on the Codman Express
  • When the Codman express displays the message "Proceed to zero monitor", press the "zero" button on the appropriate Datex monitor pressure module
  • Observe that the Datex monitor displays a pressure of "0"
  • Press the "Menu/Enter” key on the ICP Express monitor to complete the zeroing process.



The system must be zeroed to ensure the Codman pressure is correctly displayed on the Datex monitor.

Proceed to Zero



Instructions will appear on the Codman express display to calibrate the Datex monitor. The screen will prompt the user to choose either 20 or 100 mm Hg. Press the 20 key. Ensure the bedside monitor displays a waveform located on the 20 scale.

 Once the calibration is complete, press the “Menu/Enter” key to continue.


20 mm Hg is chosen when pressure readings are < 100 mm Hg. Disconnect the Datex monitor if it cannot be properly calibrated to prevent accidental treatment of inaccuarate numbers.

Calibrate  20


Connect Cables

Connect the ICP Express cable to the Codman microsensor ICP transducer.


Connection of the patient catheter to the cable is necessary to zero the catheter prior to insertion. The monitor must be zeroed to atmospheric pressure before insertion.

Transducer Detected


Prepare Catheter

Using the Codman Microsensor Basic Kit, the physician will lay 3” of the tip of the microsensor catheter flat into sterile water or saline. Do not submerge the catheter vertically.


Prepare Catheter


The catheter must remain wet during the zeroing process. Higher pressure from vertically submerging can result in erroneous zero reference values.


Zero Express

Press the “Zero” key on the ICP Express monitor while catheter is submerged. Message “Transducer zeroing in process (please wait)” will appear.


Once zeroing is complete, a 3 digit number offset number will display in the ICP express display window.



This offset value is required for reconnection if the monitor is disconnected from the patient, or if the patient is connected to a different Codman Express monitor. This value is required to zero the new system and is specific to the catheter being used.


Access Menu

 Press the “Menu/Enter” key to continue. The monitor and catheter are now ready for placement.


Preparation is needed before the intraparenchymal catheter is inserted.


Assist with Catheter Insertion

Perform hand hygiene and don non-sterile gloves.

Once catheter is inserted, assess waveform on monitor.


Presence of a good waveform ensures the catheter has been placed accurately.


Apply Dressing

Apply dressing over site (gauze or occlusive depending upon the presence of drainage).

Change dressing prn. May leave dressing off when drainage has stopped.


Prevent site contamination and to support catheter in place. This dressing can be changed prn.



Document hourly ICP from ICP Express on neurological section of the nursing flowsheet. Record hourly neurovital signs, and calculate and document the Cerebral Perfusion Pressure (CPP).


Accurate hourly recording will indicate any change in pressure reading requiring intervention.


Discard Medical Waste

Discard used equipment and supplies. Remove PPE and perform hand hygiene.



In accordance with the MoHLTC 4 moments of hand hygiene and LHSC infection control policies in an effort to reduce risk of transmission of microorganisms and secretions.


Prepare for CT

To transport the patient from CCTC or remove the Codman Express, simply disconnect the white microsensor from the Codman Express cable. If the patient has a ventricular drainage system, transport the drainage collecting chamber with the patient.

During movement or repositioning of the patient, turn the drainage system off. As soon as the patient is repositioned, adjust the level of the drainage unit and open as per the previous orders.


CT is required post insertion to check catheter placement.

Turning the stopcock off will prevent accidental over-drainage if the drainage unit was inadvertently lowered. It is important to recognize that stimulation and repositioning associated with patient transport could cause the ICP to elevate. The best way to manage this is to quickly restore the drainage collecting chamber to the ordered level and drainage position as soon as possible.


Reconnecting the Codman Express

To reconnect a patient to the Codman Express:

  • Reconnect the microsensor to the Codman Express cable
  • Press the "menu/enter" button
  • Select the "manual zero" option
  • Check the displayed reference number. If it matches the 3 digit number that was recorded at the time of insertion, select the "menu/enter" button.
  • If the reference number is different, use the arrow buttons to change the reference number to match the insertion code and select "menu/enter"
  • Press the white "zero" button (zero monitor).
  • When "Proceed to zero monitor" appears on the Codman display, press the "zero" button on the appropriate Datex pressure module
  • Wait until the pressure on the Datex monitor reads "0", then select the "menu/enter" button to confirm


The 3 digit reference must be confirmed to ensure accurate pressure readings. This code is catheter specific. If a different Codman monitor is used, the code will need to be changed to match the catheter code.


Developed: June 12, 2008
Last Update: March 24, 2010
Judy Hackett RN BScN CNCC-C, CCTC

Gina Souliere RN BScN

Updated July 25, 2013, July 26, 2014


User Manual for Codman ICP Monitoring Systems, 2001.

LHSCHealth Professionals

Last Updated July 25, 2014 | © 2007, LHSC, London Ontario Canada