Objective: Lateral fluid percussion injury model (LFPI) is widely used in experimental traumatic brain injury (TBI) research, particularly in rats.  In the classical model, a pendulum strikes a fluid-filled system connected to the dura, producing acceleration-deceleration TBI.  Accurate pendulum levelling is difficult, adversely affecting reproducibility, and the equipment bulky and expensive. To overcome these shortcomings, we have developed and validated a micro-FPI apparatus modelled on a novel system¹.

Methods: Our micro-FPI apparatus consists of a Picospritzer II TM (Parker Hannifin, Pneutronics Division, PineBrook, NJ) device that uses a high-speed valve to deliver a standardized pressure pulse of air to a standing column of fluid. Pressure pulses are triggered manually or electronically. Physiological response to injury was assessed by mortality; duration of suppression of somatomotor reflexes; and arterial blood pressure changes monitored invasively via a femoral artery cannula.

Conclusion: Our micro-FPI device produces a LFPI similar to that described by researchers using classical LFPI. Our pathophysiological data suggests that micro-FPI 40psi delivered over 20milliseconds produces moderate severity TBI.