PROCEDURE SET-UP OF HEMODYNAMIC
MONITORING CIRCUIT IN CCTC

  1. Assemble transducer pole clamp
  2. Open transducer kit
  3. Tighten Connections
  4. Prepare flush solution
  5. Prime the drip chamber
  6. Prime the air-fluid interface stopcock
  7. Prime the tubing
  8. Position stopcock for line insertion
  1. Replace vented caps
  2. Pressurize fluid
  3. Connect tubing to patient
  4. Level system
  5. Zero transducer
  6. Replace cap
  7. Examine waveform

PROCEDURE

RATIONALE FOR PROCEDURE

 1.

Assemble and tighten transducer clamp to IV pole.

 1.

  • The transducer holder frees the user's hands to facilitate ease in priming.
  • The pole clamp permits easy repositioning of the transducer to ensure correct leveling during patient position changes.

 2.

Open transducer kit and place the transducer firmly in any one of the three brackets. 

  • Insert until you hear a click. 
  • Position the transducer so that the stopcock is above the transducer and the flush device is below.
  • The tubing which leads to the patient catheter can be identified by its hard non-compressible appearance. The tubing which delivers the flush infusion is soft and compliant (like regular IV tubing).

 2.

  • Air rises to the top; placement of the stopcock above the transducer promotes easy clearance of air from the circuit. 
  • The tubing which carries the pressure wave from the patient to the transducer is hard and non-compliant to ensure that external pressure (e.g. kinkage of the tubing) cannot influence internal tube pressure and lead to false pressure recordings. The tubing which delivers the flush is positioned pre transducer and therefore has no influence on pressure measurement. 

 3.

Tighten all luer connections. 

 3.

Connections are loose during packaging to facilitate gas sterilization process. If left loose, pressure loss may lead to inaccurate readings or backup of blood. 

 4.

Perform hand hygiene, don non-sterile gloves.

Open 500 ml bag of 0.9% normal saline solution. 

  • Invert bag, placing medication administration port straight up towards ceiling. Using 18 gauge blunt needle, puncture medication administration port and eliminate all air from bag.
  • Document flushsolution on MAR 

Heparin is rarely used. If considered for a specific patient, be sure that the patient is not suspected of having HIT.

 4.

  • 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.
  • Air will rise to the top.  Keep both the port and needle at exactly 90o to the floor to prevent air bubbles from being trapped in the edges of the bag.
  • Elimination of air will prevent air bubbles from being pressurized into the circuit.
  • Air entry to the circuit will interfere with pressure measurements and can be difficult to clear from the line if it reaches the transducer.
  • Large air bubbles entering the blood stream can cause air embolus.

 5.

Spike the infusion bag with the IV tubing. Hang the infusion bag on the hook inside the Tycos infusor. Do not pressurize the system yet.

  • Open the roller clamp and squeeze the drip chamber slightly. Close the clamp and release the drip chamber. 
    • The goal when setting up the system is to have approximately 1/4 - 1/3 of the drip chamber filled with fluid. 
    • This is enough to prevent air from entering the circuit, while retaining visibility of the flow rate during flushing. 

 5

  • Pressurization prior to priming will promote small air bubbles to accumulate.
  • As soon as the system is pressurized, the level in the drip chamber will rise higher; air in the top of the trip chamber allows visualization of the rate of flushing. 

 6.

Open the roller clamp. 

  • Turn the stopcock above the transducer "OFF" to the patient line (the system will now be "OPEN TO AIR"). 
  • Gently pull the flush devise. 
  • Prime the system until all air has been evacuated.
  • Check the transducer carefully to ensure that all air bubbles have been evacuated. 
  • The white cap over the stopcock is vented; you may flush through it without removal.

 6.

  • Gravity versus pressurized priming minimizes the formation of bubbles. 
  • A solid column of fluid that is free from air bubbles must cover the transducer membrane.  Bubbles will interfere with pressure waveform transmission.

7.

Turn the stopcock above the transducer "OFF" to the vent port (air elimination port). 

  • Check that the patient stopcock at the end of the patient line is closed to the blood drawing port. 
  • The end cap is vented and can be flushed through without removal.
  • Pull the flush device to continue priming to the end of the patient tubing.

 7.

 

  • Any air bubbles in the patient tubing will dampen the transmission of pressure waveforms. 

8.

Turn the stopcock closest to the patient catheter off at a 45o angle to the blood drawing port (half-way between two ports).

 8.

  • Turning any 3 way stopcock at a 45o angle closes the stopcock in all three directions. This will prevent the circuit from dripping on the floor.
  • When pressurized, the flush device will allow 3 - 5 mL per hour into the patient tubing unless the system is turned off.

9.

Replace vented caps on blood drawing and air elimination port with leur lock dead-end cap.

 9.

All indwelling lines must have dead-end, leur lock caps to protect against bleeding out or air entry into the system.

10.

Pressurize the Tycos by turning the clamp on the back in the direction shown for "CLOSE" (clockwise).  Continue to tighten until the arm swings freely.

 10.

  • The bag must be pressurized to oppose the blood vessel pressure. 
  • Inadequate pressure will cause blood backup, inaccurate pressure readings and loss of line patency.

11.

Connect the end of the patient tubing to the patient catheter. 

  • Turn the patient stopcock off to the blood drawing port.

 11.

  • This opens the circuit to patient monitoring. 

12.

Level system

  • Position the vent port (air elimination port) on the stopcock that is located above the transducer in a position that is level with the 4th intercostal space, midaxillary line (for any arterial line, central line or pulmonary artery catheter).

 12.

  • The 4th intercostal space, midaxillary line is the reference point for monitoring cardiac pressures. 
  • When both ends of the patient tubing are level (the transducer stopcock and the heart are horizontal, the pressure that is exerted on the transducer as a result of the weight of the fluid in the tubing will be neutral.
  • If the transducer is lower than the patient's heart, the pressure exerted by the fluid column will "run down towards the transducer", falsely elevating the pressure reading.
  • If the transducer is higher than the patient's heart, the pressure exerted by the fluid column will "run away from the transducer", falsely lowering the pressure.

13.

Zeroing the Transducer 

  • Remove the cap on the vent port (stopcock above the transducer).
  • Ensure that the vent port is level with the 4th intercostal space, midaxillary line).
  • Open the stopcock above the transducer to air (turn it "OFF" to the patient line).
  • Note: the cap should be removed before turning the stopcock. 
  • Select the pressure sensor on the monitor and select "zero". 
  • When completed, the monitor will display a message that indicates "zero completed, offset is x mmHg".  The offset should be between +32 and - 32 mmHg.  If it is outside that range, a new transducer should be obtained.

 13.

  • During zeroing, the system is closed only to the patient's pressure.  All other sources of pressure (which cannot be removed) remain exerted against the transducer (e.g. atmospheric, flush device).  The monitor is then told to call this pressure "zero". 
  • When the transducer is reopened to the patient pressure, the pressure reading will reflect only that of the patient. (This is the same principle used when zeroing a bathroom scale; one ensures that the scale is at "zero" before adding your own weight).
  • If the dead-end cap is left on, or the stopcock incorrectly turned, the monitor will be unable to find an uninterrupted path to locate "zero" and will display an error message.  Recheck the stopcock and rezero if this happens.

14.

When the monitor indicates zeroing is complete, turn the stopcock closed to the vent port (air elimination port) first.

  • Once the port is closed to the air, reapply the dead-end cap.
  • When zeroing completed remove non-sterile gloves and perform hand hygiene.

 14.

  • If the cap is reapplied when still opened to the vent port (air elimination port), pressure is transmitted back to the transducer as it hits a "solid wall" from the cap. 
  • The dead-end cap protects against air entry or "bleeding out".

 

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

 

15.

You should now identify a pressure waveform and pressure recordings. 

 15.

 

Last Update: Developed 1988, October 16, 2007, August 1, 1993, march 23, 2010, April 14, 2016
Brenda Morgan, Clinical Nurse specialist, CCTC


LHSCHealth Professionals

Last Updated April 14, 2016 | © 2007, LHSC, London Ontario Canada