A MODIFIED FLUID PERCUSSION DEVICE

This report examines a modified fluid percussion device with specific improvements made to address deficiencies found in previously reported devices. These improvements include the use of a cylindrical saline r eservoir made of stainless steel, placement of the reservoir in a 15-d egree head-up position for the easy release of air bubbles, placement of the fluid flushing outlet and the pressure transducer close to the piston on the same plane, with both perpendicular to the direction of the piston, an adjustable reservoir volume to vary the waveform of the pressure pulse, and a metallic central injury screw secured to the an imal's skull over the exposed dura. Using this device, midline fluid p ercussion (MFP) and lateral fluid percussion (LFP) injuries were perfo rmed in 70 rats. Histopathologic findings included diffuse axonal inju ry in the MFP model and cortical contusion in the LFP model. Survival rate was 41.4% in MFP animals and 100% in LFM animals when the device settings were 178 mm(3) of the cylindrical reservoir and 50 degrees-60 degrees in height of the pendulum. Our results suggest that this modi fied fluid percussion device may offer significant improvements over p reviously reported fluid percussion models for use in experimental hea d injury.