Transonic Measurements

What is delivered flow and why is it useful?

The delivered flow measurement calculates the difference between the dialysis machine pump setting and the actual delivered flow. The result is displayed as green for ‘pump speed is delivering flow within 10% of the setting’ or red for ‘pump speed is not delivering flow as prescribed’. This can be used to help diagnose any whole circuit issues that are not detectable by the dialysis blood pump calibration discrepancy. Delivered flow can be measured on a haemodialysis catheter, AV fistula or AV graft using Transonic.

What should I check if the delivered flow is more than +/- 10% in difference to the prescribed flow/ pump speed?

– Needle size & placement

– Condition of access

– Roller pump tubing segment occlusion or kinked dialysis tubing

– Have the bloodlines been changed recently and is the correct blood line selected?

– Have the dialysis machine and the Transonic sensors been calibrated?

With a haemodialysis catheter the blood flow rate can be adjusted down to achieve the desired delivered blood flow rate.

What is access flow and why is it useful?

The access flow option measures the blood flow through the AV fistula or AV graft by reversing the dialysis bloodlines and measuring the transit time of a Saline bolus given through the venous bubble trap. This method was invented by Transonic’s Senior Scientist Dr Nikolai Krivitski in 1995.

All current haemodialysis patient flow surveillance guidelines are based on over 200 publications by Clinicians from around the world using Transonic HD monitors. The Transonic HD03 allows access flow measurements to be taken in under 5 minutes at the patient’s bedside during routine haemodialysis rather than the patient having to book an additional outpatient appointment for a Doppler scan.

When should the access flow measurement be taken during the patient’s dialysis session?

Due to the drop in blood pressure, change in pulse or cardiac function during the dialysis session, it may be better to take dialysis measurements in the first third of the treatment session. For example, if the total dialysis session is 4 hours it would be preferential to take the measurement within 1 hour 30 minutes.

What happens if I get a noisy baseline during access flow measurements?

There are 2 possible causes:

– There has been a change in pump speed less than 60 seconds prior to the Saline bolus.

– The bolus was given too quickly.

Ensure that lines are reversed and that the pump speed setting is reduced when prompted before progressing to the next screen. If the noisy baseline message persists the bolus may be travelling too quickly. Try using a 20ml Saline bolus and lowering the BFR to 200 ml/min.

What is the recirculation measurement and why is it useful?

Recirculation is where filtered or ‘cleaned’ blood from the dialysis machine is being drawn up by the arterial needle rather than being returned to the body. The amount of recirculated blood is shown as a percentage of delivered flow and the desired reading should be 0%. This is useful as, again, it can be used to ensure that the patient is receiving the prescribed blood flow and rule out inadvertent reversal of bloodlines.

Recirculation also occurs with haemodialysis catheters where blood returning into the patient from the dialyser is pulled back into the arterial bloodline. The recirculation measurement can determine if line reversal done to “improve” flow is actually impacting adequacy of the dialysis.

What should I check if recirculation is more than 20%?

Any recirculation is abnormal. If recirculation is above 20% then check correct needle placement before proceeding.

What should I check if recirculation is above 5%?

Take a second measurement and if the recirculation measurement is 0% then a third deciding measurement should be taken. If the measurement is borderline i.e. below 5% then the pump speed should be increased to confirm recirculation.

How do I check if recirculation is caused by inadvertent reversal of dialysis bloodlines?

Intentionally reverse the bloodlines and measure recirculation again. If the second measurement is 0% or less than the first recirculation measurement then it is likely that the original position of the bloodlines was incorrect and the bloodlines are now the correct way around. This should be documented to prevent recurrence of inadvertent blood line reversal.

What is the cardiac output measurement and why is it useful?

Cardiovascular Heart Disease is responsible for half the deaths and one-third of hospitalisations of dialysis patients. The only other method available to measure cardiac output is by using a Pulmonary Arterial (PA) catheter which is an invasive procedure. The Transonic HD03 can measure cardiac output, which is the volume of blood being pumped by the heart in 1 minute, at the patient’s bedside without the need for a PA catheter. This measurement combined with the patient’s Body Surface Area (BSA) parameters and the access flow measurement can be used to measure the effects of haemodialysis on the patient’s heart.

What does cardiac output and access flow measurements identify?

– Prolonged high access flow to cardiac output ratio that stresses the heart and can result in cardiomegaly and heart failure.

– Dangerously low cardiac index that places patients at high risk of cardiovascular complications and failure.

– Dramatic decreases of cardiac index during haemodialysis due to inaccurate dry weight estimation and/or inadequate medication.

– Dangerous decrease in central blood volume during haemodialysis that may portend hypotensive episodes.

What additional equipment is required to carry out cardiac output measurements?

– Cardiac output enabled Data Transfer Module (Product Code: DTM-CO)

– Saline Warmer (Product Code: HFW1000)

– Flow QC-Clear Advantage Dialysis Tubing (Product code: ADT1010)

Please contact your local Kimal Representative for more information.

Can access flow and cardiac output be measured in central venous catheters?

Only delivered flow and recirculation can be measured in CVCs. There are inadequate mixing conditions for the Saline with catheters and the measurements cannot be used.

How often should cardiac function parameters be measured?

Patient profiling is performed to establish and confirm the adequacy of medication dosages and the haemodialysis prescription. A patient’s cardiovascular baseline consisting of monthly measurements over 2 consecutive months can then be established by measuring cardiac output. This baseline should be established when a patient first enters into the Transonic monitoring program and repeated when the patient returns from a hospitalisation. After the baseline period the Nephrologist determines a measurement regimen for each patient including a prescribed testing interval i.e. quarterly, monthly, whether an analysis of fluctuations in cardiovascular parameters induced by haemodialysis should continue, and the threshold at which changes in critical cardiac parameters should be brought to the attention of the Nephrologist.

Common error messages

The display has changed to show Please insert Data Transfer Module (DTM)

Shut off your system and reboot in order to regain normal functionality. If the Transonic is plugged in when this happens there has been a power surge in the AC adapter and the DTM has reset to protect the data. If this happens frequently then contact the Hospital Maintenance department to check the building’s electrical supply. This should not happen if the Transonic is not plugged in and running off the battery. If this occurs frequently contact Kimal’s Customer Care team.

The dialysis machine alarms and the dialysis pump stops when I deliver the Saline bolus during measurements.

Open the venous pressure alarms to avoid pump stoppage. Ask your Renal Technician to advise how to do this with your particular dialysis machine.

Ultrasound signal quality indicator is not full or there is a negative delivered flow on the HD03 monitor.

– Check that the sensors are on the blood line tubing, not on the needle tubing.

– Check that the arterial sensor is on the arterial blood line and the venous sensor is on the venous blood line.

– Check that the arrows on the sensors are pointing in the direction of flow.

– Remove the sensors and re-apply using alcohol to wet the tubing segment or sensors.

The Transonic HD03 monitor screen has gone black/blank

This is a screensaver which comes on after a period of no user operation. Just tap the screen to wake the HD03 up; you may need to press more firmly when using gloves. It’s recommended that you switch the Transonic off to save battery if not being used for an extended period of time i.e. in between dialysis shifts.

Equipment Cleaning and Care

The exterior surfaces of the HD03 can be cleaned with a damp cloth. The touch screen and monitor surface can be cleaned with a cloth dampened with a 1% bleach solution. Do not drop liquids onto the monitor. Keep the HD03 monitor in a dry environment and do not operate in wet conditions.

The flow/dilution sensor, cable and outer shell of the connector should be cleaned with a cloth dampened with a 1% bleach solution, an alcohol wipe, or a mild disinfectant soap solution. Do not immerse Sensor or connector. Regular cleaning is important to prevent the possibility of patient cross-contamination.

Calibrations & repair

Why does the Transonic need calibrating?

The Transonic HD03 needs to be calibrated every 12 months by Transonic engineers to ensure the flow sensors are both functional and providing accurate measurements. A full inspection of the HD03 monitor is also carried out to ensure all parts are functioning correctly, with further recommendations being made in regards to replacement of any ancillary parts due to wear and tear.

All Transonic calibrations:

– Guarantee quality, reliable measurements.

– Come with certificates to meet ISO standards.

– Include all necessary software and hardware updates (ECN).

Why do I need to keep the packaging?

The Transonic packaging includes soft, padded inserts and is purpose built to ensure the safe shipping of the HD03 monitor and the flow sensors. Transonic WILL NOT accept equipment in anything other than the original packaging for insurance and shipping purposes. If required, a replacement box will need to be ordered prior to your Transonic being collected for a fee of £60.

How do I arrange for my Transonic to be calibrated or repaired?

Please complete the work request form to arrange a service and you will be contacted by Kimal’s Customer Care team.

The form will ask for the serial number, address of the Dialysis Unit it is to be collected from and contact details. If you believe that your HD03 monitor is damaged please provide details of why you believe this is and any troubleshooting steps tried.

How do I check the serial number and service ‘due date’ of my Transonic HD03?

Both can be found by going to the System Info option.

Do I need to return my Data Transfer Module (DTM) along with the Transonic HD03 machine?

No, the DTM is not required for calibration of your HD03. This is because Kimal or Transonic cannot be in posession of patient data in accordance with new General Data Protection Regulations. As a result any DTM received by Kimal is restored to factory settings, deleting all information. It is therefore advised that customers do not include their DTM when sending their HD03 system.

What model of Transonic do I have?

If the Transonic requires a laptop to function then it is the previous HD02 model.

Since November 2017 calibrations and repairs are no longer provided by Transonic on the HD02 model. Notification of this has been sent to all HD02 customers since 2015.

The latest model is the HD03 which has a touchscreen interface and is battery operated. To arrange calibration or repair of your Transonic HD03 monitor please complete the work request form to arrange a service and you will be contacted by Kimal’s Customer Care team.