ECMO Console/ Heater/ Blender

ECMO console is situated at the foot of the bed with the pump head and oxygenator facing toward the patient. The gas and blood flow control face away from the patient. Power cords and gas tubing must be not tangled with the ECMO circuit and must not protrude onto the floor space around the patient bed. Torsion on the ECMO circuit is to be avoided.

The pump head needs to face up, not to be angled more than 90. Also, position the pump head horizontally above the oxygenator. In the case of air embolism, this will trap air first in the pump, potentially stall it before overwhelming the oxygenator and returning air to the patient.

Note: dual lumen jugular catheter (Avalon®) configuration for VV ECMO and femoro-jugular configuration for VV ECMO the standard circuit tubing length will be insufficient to reach an ECMO trolley situated at the foot of the bed. In this case, the trolley is positioned at the patient’s left or right side. It will be re-positioned to the top of the bed for intrahospital transport.

Oxygen connections

After initiation of the patient on ECMO or upon return to the cubicle the oxygen supply has to be transferred from the portable oxygen to “wall” oxygen and the blender alarm is tested during connection (audible alarm). The fresh gas flow meter should be set to the desired gas flow. The reading should be made from the centre of the “ball” on the flow meter.

The outlet tubing from the fresh gas flow meter (before the oxygenator connection) is briefly occluded as the “ball” in the flow meter is observed. Shifting of the “ball” in the flow meter in response to the occlusion indicates a functioning fresh gas flow meter.

Fresh gas tubing is connected to the oxygenator inlet. Ensure only selected high (up to 10L/min) or low flow (up to 1L/min) side of fresh gas flow meter is on and not both (unless you deliver 11L/min).

Transmembrane Pressure Monitoring (Rotaflow only)

Once ECMO support is established, pre- and post-oxygenator pressure monitoring can be established.

Connect a pre-primed and pressurised transducer and bag to the extensions on the pre- and post-oxygenator port. Aspirate via the 3-way tap and then open the tap to the circuit.
Ensure the bag is pressurised to 300mmHg and hung below the drive console and away from the external drive unit
Connect transducers to pressure modules, select appropriate monitor labels and zero.
Record the transmembrane pressure gradient hourly (the difference between the pre- and post-oxygenator pressures)
A normal gradient should be between 20 to 40mmHg. Higher readings may be related to clot formation within the oxygenator or excessive flow rates. For more details see haemolysis.

The pressurised fluid bag for transducing the pre and post oxygenator pressure in the PLS circuit must be located below the level of the ECMO drive console and not above the external drive unit. This will ensure that no fluid spills into the console or the external drive unit in the event of fluid bag rupture.

Cardiohelp/HLS utilises internal pressure monitoring characteristics and does not require external pressure monitoring (see HLS priming and HLS zeroing).

ECMO Console settings

The following abbreviations are used on the display to specify the settings

Alarm Settings

Flow limit (ECMO blood flow) Alarm is set 0.5 L/min below target flow
Speed setting Alarm: High and Low-Speed Setting Limits are set 500 RPM above and below the current RPM. This is to alert beside staff to manual pump speed settings changes.

Speed setting

The pump speed RPM is selected to deliver the desired circuit blood flow. The pump speed setting required to achieve a given circuit blood flow is dependent on the resistance to flow in the circuit and the load across the circuit. Speed settings are chosen by ECMO accredited ICU bedside staff only.

Mode setting

Rotaflow System defaults to the “FRE” mode when started. This indicates that the device is not connected to any external peripheral device such as a roller pump used during bypass, bubble detectors, or reservoirs. The MODE option should never be selected or changed in the menu options as this will shut down the pump.
Cardiohelp System defaults to “therapy” mode on startup. Two modes for use at the bedside are ‘VV’ or ‘VA’ modes. This needs to be changed in the menu option and then the relevant mode selected. Other options are available: e.g. PALP or VAD but not used at present. Changing the mode will not affect the running of the pump, but will alter the display and monitored variables. Only the ‘VV’ or ‘VA’ modes are to be used at the Alfred ICU.

Caution LPM Function

LPM stands for ‘liters per minute’. Both the Rotaflow (“LPM Mode”) and Cardiohelp consoles offer the LPM function which, when set, will run the pump speed automatically to achieve a selected blood flow target. This function is unsafe during episodes of Access Insufficiency. This function should never be used at The Alfred.

Interventions setting

Only the Cardiohelp HLS system has the added functionality of setting “Interventions” around certain clinical parameters such as circuit pressures and blood flow. When “Interventions” are enabled, the device automatically controls interventions in response to bubble, circuit blood flow, or pressure alarms. WE DO NOT SUPPORT THE USE OF INTERVENTIONAL SETTINGS WITH THE CARDIOHELP ECMO DEVICE IN THE ALFRED ICU due to the risk of unintentional alterations to (including discontinuation of) ECMO support.

Heater unit management

Heater unit set up

It is essential to warm the heater before connection to an oxygenator on a running circuit that is connected to a patient (otherwise the patient is cooled).

Ensure that the heater water level is approximately 75-80% full. This is indicated via the water level on the front of the heater. If low escalate to the ECLS CNC or respiratory support. The heater protocol enables change of water and/or top-up of water. This should be carried out in the respiratory room and away from the clinical cubicle.

Ensure to connect the bridging device between the heater hose ends to aid recirculation (see picture below). Also, make sure to reattach it when disconnecting a patient to make sure it is not lost.

The brass coloured connection to the ECMO console here shown with the bridging device, comes in a straight and angled version which is better suited for the use with the HLS circuit.

Turn on unit and recirculate water until desired temperature attained (usually 37°C), this will only take a few minutes
Turn off the heater unit prior to attaching hoses to an oxygenator (pull the gold rings in a downward motion and reattach to the connectors on either side of the oxygenator (same connections for HLS or PLS oxygenator).
Turn on the heater unit once hoses are attached to the oxygenator, monitor patient temperature and set the heater accordingly.

Further related links

General heater information, user manual

Heater alarms

Temperature management

Blender settings

The fresh gas flow (FGF) on the blender is set routinely to 100% O₂ and should not need to be changed during weaning. This is to prevent unintentional inadequate O₂ delivery when oxygenator V/Q is less than 1. This practice may be reconsidered as evidence emerges about the role of hyperoxia in the setting of ischaemia/ reperfusion and is currently investigated in the BLENDER trial. Patients enrolled in the trial may have altered blender settings. VV ECMO patients are always set to 100% O₂.

The fresh gas flow is set here to 3.75 L/min (the flow is read in the middle of the ‘ball’). with a FiO₂ of 1.0.

Console checklist

ECMO console positioning and set up

Oxygen connections

Transmembrane Pressure Monitoring (Rotaflow only)

ECMO Console settings

Heater unit management

Blender settings

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