Key Points
- To examine the mechanical impedance to pulsatile blood flow in the canine hind limb vascular bed and characterize the dynamic physical factors governing circulation.
- Diverted canine femoral arterial flow through an external loop fitted with an electromagnetic flowmeter and a Statham pressure transducer.
- Recorded simultaneous pulsatile pressure and flow waveforms onto 35-mm film and performed Fourier harmonic analysis using a frequency converter and wave analyzer.
- Computed mechanical impedance as the ratio of pressure-to-flow harmonic amplitudes and formulated a two-branch parallel electrical analog circuit to model the system.
- Mechanical impedance curves revealed two distinct resonant frequency bands: one between 3.6 and 4.6 cps and another between 5.6 and 7.0 cps.
- Impedance reached a minimum value of approximately 1.2 peripheral resistance units at each resonant frequency peak.
- The theoretical electrical analog circuit qualitatively matched the experimental impedance-frequency curve, validating dynamic relationships among vascular elastance, inertia, and friction.
Structured PICO
PPopulationDogs (femoral peripheral vascular bed of the hind limb)
IInterventionMeasurement of pulsatile blood pressure and blood flow via external polyethylene tubing with an electromagnetic flowmeter and pressure transducer
OOutcomeMechanical impedance to blood flow (amplitude of pressure harmonic divided by amplitude of flow harmonic)surrogate
This preclinical study characterizes the mechanical impedance to blood flow in the canine femoral artery, identifying specific resonant frequencies and proposing an electrical analog model.