MGI MEDICAL
"OVERCOMING THE LIMITATIONS OF
CONVENTIONAL HEMODYNAMIIC MONITORING"
CONVENTIONAL HEMODYNAMIIC MONITORING"
Basic Principles of the Pulse Flowmeter
Peripheral Pulse Volume (PPV) is the small change in
the volume of a portion of a limb that occurs when blood passing through a limb
expands and contracts the arteries and arterioles Peripheral pulse flow (PPF)
is PPV multiplied by heart rate. The limb is an
electrical conductor whose electrical impedance changes with limb geometry and
volume. This change in volume is very small, on the order of 1 part per 10,000
and is therefore normally obscured by electrical and mechanical noise see fig 2 below). “Plethysmographs”
are devices that measure volume changes of a part of the body.
Each time the heart beats, the volume of the limb segment changes, producing an impedance “plethysmographic waveform.” By applying signal processing techniques to this waveform, a highly reproducible pulse volume signal is generated.
