The DRAGONFLY R&D INC. Model HPD-1700 is used to create reproducible closed CNS/brain trauma injury in the laboratory rat. This device consists of a closed hydraulic system actuated by a falling pendulum. The pressure with which the pendulum strikes the closed hydraulic system is adjusted by changing the angle through which the pendulum falls or by adding optional weights to the pendulum. The system pressure is measured directly by a precisely calibrated pressure transducer through a charge amplifier/coupler to a digital or analog oscilloscope (digital dual-trace with RS232 output is ideal), or most PC based data acquisition systems (high impedance input required). The timebase of the oscilloscope in combination with the correct time.
The oscilloscope must be set to trigger on a positive or rising trigger pulse. The storage function of oscilloscope should be turned on. The time duration of the impact or pressurization event occurs in approximately 10ms with the flat faced striker plate, however, it can be lengthened to 20ms or more by gluing shock absorbing closed cell foam on the striker plate of the piston. The time duration is read directly on the oscilloscope using screen grid as reference.
The closed hydraulic system is attached to the animal model using a flexible high pressure hose attached to a chronically implanted Luer lock fitting on the rat’s skull.
|Instruments Dimensions||W510 × D305 × H530(mm)|
- Main Unit – 1
- Pressure Transducer – 1
- Amplifier – 1
- Magnetic Switch for Oscilloscope Trigger – 1