|Non-invasive measurement of blood flow in humans is commonly made using techniques applicable to fore-arm blood flow. For a short discussion of techniques, please see our application note. Components shown here are for fore-arm flow measurement using strain-gauge plethysmography (SPG).|
Strain Gauge Amplifier
We can supply a variety of occluding cuffs from Hokanson, but the cuffs that we particularly recommend for fore-arm blood flow are the SC10D size. These are 11 x 85 cm overall, and are fitted with a very large bore tubing connector to allow for rapid inflation (and deflation) - especially important for finding the initial rate of limb swelling due to arterial inflow.
Narrow cuffs for a wrist tourniquet, and other cuffe sizes for the lower limb, are also available.
For rapid and easy inflation of the occluding cuff, we recommend the E20 Rapid Cuff Inflator from Hokanson, together with the AG101 Air Source. The E20 inflates any cuff in 0.3 sec, holds the pressure indefinitely or for whatever time your protocol needs and then deflates the cuff in 0.3 sec. Works every time no matter the size of the cuff or leg. Simply dial in the pressure needed, and push the button for inflation and then push the button to deflate. A built-in cycle timer is available as an option.
The AG101 is a whisper-quiet matching air compressor, which is dependable and of adequate capacity to repetitively inflate an occlusion cuff.
|To acquire the results of repeated limb occlusions and to actually measure the corresponding flow, we recommend a BIOPAC data aquisition system. This makes the analysis particularly easy - a cursor is dragged over the relevant period of the waveform and the resulting least-squares slope transferred to a journal (log) with a single keystroke. The BIOPAC system is available for either Windows or Macintosh, and can be expanded for a whole range of other physiological measurements.|