Patient and ECMO monitoring

Visual inspection

Visual inspection can provide a very quick overview of the ECMO support

• Patient status on the monitor, oxygen saturation and degree of pulsatility
• Presence of colour differential in the ECMO tubing
• Display panel on the console
• Visual inspection of the cannula site and circuit

A detailed checklist, however, can not be replaced and is required to be performed meticulously to ensure all components of care and safety backup are delivered to the patient.

Checklists

Checklists are now on powerchart in 2 tabs

• ICU Safety Checks – ECMO (if single console for ECMO or temporary VAD)
• ICU Safety Checks – ECMO 2 (if second console)
• Cannula – measurements & dressings
• ECMO setup – relates to console and equipment
• ECMO setup2 – (only if second console)
• Patient observation – neurological and neurovascular can be entered under different fields

Daily ECMO care commences with handover by the bedside. Both the outgoing and the oncoming staff should physically complete the observations and assessments together. These include

• Neurological observations (hourly)
• Vascular observations (hourly)
• ECMO cannula checks
• Circuit checks
• Handover should be with a systematic handover tool such as ISBAR and signed off with both staff

Safety checks

Hand Crank

• Check the hand crank is present and in an appropriate position to facilitate use in an emergency situation. Ensure the emergency hand crank is nearer enough to the pump head and that the handle is easily accessible and can be turned 380 degrees.

Spare Console Location

• Check the spare console (HLS/PLS) for the console being used and plugged into A/C power (outside bed 1)

Flow Sensor Grease

• Check that there is flow sensor grease available on the console present (PLS only)

Check Water heater

• Check the level of water in the water heater by looking at the clear column on the left side of the water heater unit. If the level is less than half, liaise with the ECLS CNC or ICU consultant. (the water heater needs to be filled up or swapped out in the respiratory area (not in the clinical cubicle). The ECLS CNC or consultant can do this. The bedside nurse delegates this task.

Ensure yellow cap is on the de-airing port

• Ensure a yellow (or red) cap is present on the de-air port. (This is the port on the upper aspect of the oxygenator (on the pre oxygenator side). The port is passive. (cannot aspirate air from this port).

Cannula Position on x-ray

• Compare the position on x-ray to previous. If the position is different or there any concerns escalate to the ANM, ECLS CNC and medical staff immediately to deem if intervention is necessary.

Check spare oxygen tubing is long enough

• Check the tubing reaches from the ECMO console to the oxygen flowmeter at the head end pendant. Check the tubing has rubber ends to enable easy connection to the console/flowmeter.
• Confirm oxygen is attached to the blender.
• Check the oxygenator is connected to the blender FGF oxygen supply (and not the green emergency tubing unless transport is iminent).

ECMO Therapy Checks

Check Connection to AC power

• Check the console plug is in a blue UPS port.

Check Green AC LED is ON

• Check the green AC illuminator light is lit

Time for Battery Life

• Switch the AC power switch off. The console (HLS) will commence an audible intermittent alarm (yellow alarm). The console will be on battery. Unlock the console screen. Touch the Battery icon (this should be flashing), the screen will change and display the % of battery life). Document the number displayed.

Check Battery charge >24V

• Switch the AC power switch off. The console (PLS) will commence an audible intermittent alarm. The console will be on battery. The LED display on the left-hand side of the console will be flashing a numeric indicating the Voltage of the battery e.g. 24.6V. Document the number displayed. If the voltage displayed is less than 24V escalate to the ANM, ECLS CNC. If transport is required the console may need to be swapped electively.

Mode

• On the PLS console check the mode is ‘FRE mode’ (displayed on the left-hand side of the console).

Check therapy Mode is set to RPM

• On the HLS console check the RPM is highlighted blue.

Oxygenator in use

• Document whether the oxygenator is in use (ECMO) or if no oxygenator is in the circuit (temporary LVAD circuit).

ECMO Therapy Checks

FLIM (Lower flow alarm)

• On the PLS console set the FLIM alarm 0.5 L/min less than the ECMO therapy

LLIM (Lower speed alarm)

• On the PLS console set the LLIM alarm 500 rpm less than the ECMO therapy

HLIM (Upper Speed limit)

• On the PLS console set the HLIM alarm 500 rpm more than the ECMO therapy

Check ALL interventions are OFF (HLS Only)

• Unlock the console. Go into the ‘interventions/chain’ menu and ensure there are no ‘red chain’ intervention symbols on. Turn off the intervention for each parameter if required. NO CHAIN SYMBOLS/INTERVENTIONS should be visible.

Check intervention for bubble detection is OFF

• Check there is no chain intervention in the ‘bubble parameter’. There should be NO CHAIN SYMBOLS/INTERVENTIONS this woul STOP THE PUMP in the presence of a bubble.

Check Alarm Status is OFF

• Check the global override is not activated (there should be no red lights on the right-hand side of the screen in the alarms section).

Low Flow Limit

• On the HLS console set the low flow parameter alarm 0.5 L/min less than the ECMO therapy

High Flow Limit

• On the HLS console set the high flow parameter alarm 0.5 L/min above the ECMO therapy

Pressure alarm, Venous (Pven)

• On the HLS console, set the Pven pressure parameter alarm -20mmHg more negative than the ECMO therapy e.g. if the Pven pressure is -80mmHg set the alarm at -100mmHg.

Pressure alarm, Internal (Pint)

• On the HLS console set the pressure parameter alarm 50mmHg more than the ECMO therapy e.g. if the Pint pressure is 190mmHg set the at alarm 240mmHg.

Pressure alarm, DeltaP

• This is a derived measurement from the pre oxygenator pressure (Pint) minus the post oxygenator pressure (Part) The alarm should be set 5mmHg above the current Delta P parameter.

Pressure alarm, (Part)

• On the HLS console set the post Oxygenator pressure (Part) parameter alarm 50 mmHg more than the ECMO therapy e.g. if the arterial pressure is 170mmHg set the alarm at 220mmHg.

ECMO Cannula Checks

• The cannula needs to be documented as inserted into Powerchart by using the lines and device menu and added by clicking on the dynamic group icon (top left icon on documentation screen that looks like a graph) by the medical staff.
• NO documentation can be completed until the line has been added to the patient’s profile.

The ECMO Cannula documentation is completed when the cannula is inserted by the medical staff.

The cannula checks are made by the bedside staff. These are documented on the ECMO checklist. The cannula needs to be measured from the skin (site of insertion) to the metal reinforced part of the cannula. Cannulae should have transparent dressings over the cannula site to enable easy and consistent observation, measurement and assessment. Any change in the measurement needs to be identified and escalated to the ECLS CNC, ANM, and senior medical staff.

The Circuit

Circuit Observations

These need to be documented hourly. If the patient is on transport to another clinical area (e.g. Cath lab) there is a BMW available to complete the documentation in a timely manner.

Pump Flow

• Document the pump flow hourly (if the flow has dropped more than 0.2 L/min escalate to the ANM, ECLS CNC, and medical staff)

Pump Speed

• Document the pump speed hourly. This should be set as the ECMO should be in RPM mode. If the setting is different, escalate to the ANM, ECLS CNC and senior medical staff

Fresh Gas Flow

• Document the Fresh gas flow (FGF) hourly. Only change the FGF by 1 L/min in each intervention. Changes need to be done in collaboration with the ANM, ECLS CNC and senior medical staff

FiO₂ (oxygenator)

• Document the FiO₂ on the oxygenator hourly. Changes need to be done in collaboration with the ANM, ECLS CNC and senior medical staff

Pre-Oxygenator pressure (Pint)

• Document the pre oxygenator gradient hourly (if the pressure is more 20mmHg more than previous or changed drastically since the last hour/ measurement, escalate to the ANM, ECLS CNC, and medical staff). An increase or decrease in blood flow will also increase or decrease the oxygenator pressures.

Post-Oxygenator pressure (PArt)

• Document the pre oxygenator gradient hourly (if the pressure is more 20mmHg higher or changed drastically since the last hour/ measurement, escalate to the ANM, ECLS CNC, and senior medical staff

Oxygenator Gradient (delta P)

• Document the gradient across the oxygenator (Delta P) hourly (if the pressure is trending up or changed drastically since the last hour/measurement, escalate to the ANM, ECLS CNC, and senior medical staff).

Access line activity

• Assess the access line for movements. ‘Still’, ‘Moving’ or ‘Kicking’. Document the parameter hourly. Escalate to the ANM, ECLS CNC and Medical staff if ‘Kicking’ occurs immediately.

Check for clots in the oxygenator

• Visibly examine the oxygenator and lines for clot or fibrin. Escalate any changes or concerns to the ANM, ECLS CNC and medical staff.

Backflow Cannula Flow (use torch)

• Visibly examine the backflow cannula for flow and patency. Escalate any changes or concerns to the ANM, ECLS CNC and medical staff.

Venous Pressure (HLS only)

• Document the parameter hourly. Escalate any changes or concerns to the ANM, ECLS CNC and medical staff.

SvO2 (HLS only)

• Escalate any changes or concerns to the ANM, ECLS CNC and medical staff.

Escalate any changes or concerns to the ANM, ECLS CNC and medical staff.

Arterial blood gas monitoring and Fresh Gas Flow

Patient Arterial Blood Gas (ABG)

Routine ABG sampling is performed by bedside nursing staff commonly every 2-3 hours unless directed otherwise. Changing FGF in response to patient ABG by bedside nursing staff is also permitted, but adjustments should be discussed with ECLS coordinator and/or medical staff. Changes to lung ventilation should be discussed with the medical staff regardless.

Fresh Gas Flow Settings for VV ECMO

The objectives of lung ventilation strategies are described under ventilation.

Fresh Gas flow adjustment is made on the basis of the patient’s arterial PaCO₂ and the respiratory effort.

• In response to high arterial PaCO₂, FGF should be increased. If the oxygenator ventilation/perfusion ratio is > 2 (i.e. FGF is more than twice the ECMO blood flow), or FGF is already at 11L/min, medical staff should be notified and the possibility of oxygenator malfunction considered.
• In response to low arterial PaCO₂, FGF should be decreased, however maintained as a minimum at half the blood flow rate. Once the FGF is zero, the patient is no longer supported by ECMO

PaCO₂ can not independently be assessed from the respiratory effort of the patient. Some patients will require a low PaCO₂ to control unwanted or excessive respiratory effort.

Fresh Gas Flow Settings for VA ECMO

Lung perfusion is reduced in VA ECMO due to reduced pulmonary artery blood flow. In general, end-tidal CO₂ (ETCO₂) levels are therefore a marker of lung perfusion and right ventricular output. Ventilation is generally set to relatively low minute ventilation and arterial CO₂ is adjusted by the fresh gas flow.

• In response to a high arterial PCO₂, FGF should be increased
• In response to a low arterial PCO₂, FGF may be reduced provided V/Q is greater than 0.5 (i.e. the FGF is more than half of the ECMO blood flow) AND at least 1.5L/min. V/Q ratios below 0.5 may result in hypoxic post oxygenator blood. Most commonly, low PaCO₂/elevated pH are due to excessive patient-driven lung ventilation rather than the FGF setting.
• Never turn off the FGF in VA ECMO for a low PCO₂ as this will result in hypoxic blood being delivered to the regions of the body supplied by the ECMO circuit (frequently the lower limbs and abdominal viscera where oxygen saturations are not monitored)

Additional flow meter

Whenever there is an additional limb in the circuit, it is essential to know the differential flow in each limb since the ECMO console will only indicate total flow. Continuous monitoring and documentation of flow in each limb are preferred over intermittent monitoring.

The additional limb flow needs to be documented once per shift and immediately escalated if any concerns.

Common scenarios

• Second venous access cannulae e.g. bi-caval drainage or high flow configuration
• LV vent – measure access from vent
• V-AV with arterial and venous return

In ⅜ inch tubing, the minimal flow rate in each limb should be at least 1.5L/min and ideally relatively evenly distributed between the two limbs. Flow rates in ¼ inch tubing are less critical given the lower diameter and the higher blood velocity.