Bluetooth Device for measurement of Limb Occlusion Pressure (LOP)
Practical Application – How to Find LOP via Bluetooth
- Download the corresponding App
- Connect the Bluetooth Unit with your phone via standard bluetooth tech
- Attach the Cuff to the most proximal part of the limb you want to assess – Please remember to have a tight fit for the lower body!
- Connect the Bluetooth Unit with the hose of the Fit Manometer
- Connect the Bluetooth unit to the Cuff
- Completely rest the corresponding limb and follow the displayed guide provided by the App – Please remember that the Bluetooth Device will deflate the cuff automatically
- After appropriate measurement you will find SYS (SBP) on the top left corner on the App
- Detach the Bluetooth Unit from the Fit Manometer
This is the Limb Occlusion Pressure (LOP) for that limb in that particular position, just as the standard but prolonged method with a hand held Doppler.
When preparing for exercise just set the pressure relative to SYS (40-80%) but without the Bluetooth Device.
Troubleshooting – Relevant for Assessment of Lower Body LOP
If you have any sort of problem using this device please try the following:
- Completely deflate the cuff – please follow this link for a guidance on complete deflation.
- Make sure you have a very tight fit of the Cuff before inflation.
- Even the slightest movement interfere with the measurement and can make it impossible to measure LOP.
- Try pumping up to about 300 mmHg before you let the Bluetooth Device deflate the Cuff. 230 mmHg SYS(LOP) is the maximum measurable pressure, so if you have excessively large thighs it might not be possible to measure.
- SYS/LOP will drop slightly if you do consecutive measurements.
- There may be a variance of 5-15% of SYS/LOP relative to body positioning, e.g. seated vs. lying.
- If you receive the message displayed on the 1. picture, then you should manually control the deflation speed as shown on the 3. picture. The green graph should look like this on your phone, only the very peak is allowed outside the white window..
- Turn the wheel on the Fit Manometer to slightly speed up the deflation time as shown below. Please be patient as it can take some time to get it just right – practice makes perfect!
How the Device works
Research has shown that this method (oscillatory blood pressure measurement), is more precise compared to a hand-held Doppler ultrasound, relative to the golden standard i.e. invasive methods. Our preliminary testing is showing a very good inter-rater reliability, by comparing this bluetooth device vs. LOP assessment by hand held Doppler, as a variance of only 3-6%.
If you would like to know more about the Bluetooth Device and oscillatory blood pressure measurement, please see our Blog page (February 4, 2020)
“In conclusion, this study supports the use of limb occlusion pressure measurements as a potential alternative measure of systolic blood pressure (when both cuffs are of similar widths).” Zachary et al. (2020) (6)
Disclaimer: When assessing Blood Pressure you should always use a calibrated cuff in terms of the width of the cuff relative to the limb you are assessing. That is why you can not use Fit Cuffs to measure blood pressure and the new unit is only valid for assessment of LOP.
(1) Babbs (2012) Oscillometric measurement of systolic and diastolic blood pressures validated in a physiologic mathematical model.
(2) Berger et al. (2001) How Does It Work? – Oscillatory blood pressure monitoring devices.
(3) Beevers et al. (2001) ABC of hypertension Blood pressure measurement Part I -Sphygmomanometry: factors common to all techniques. Clinical review.
(4) Croft & Cruickshank (1990) Blood pressure measurement in adults: large cuffs for all?
(5) Jordanow et al. (2018) Comparison of oscillometric, Doppler and invasive blood pressure measurement in anesthetized goat.
(6) Zachary et al. (2020) Limb Occlusion Pressure: A Method to Assess Changes in Systolic Blood Pressure