Development of a fluid-filled catheter system for dynamic pressure measurement in soft-tissue trauma

摘要

In victims of motor vehicle crashes, rapid increases in internal fluid pressure may play a role in causing injury to solid abdominal organs such as the liver. The objective of this study was to develop a practical and cost-effective technique to measure impact-induced pressure changes within physiologically pressurised porcine liver specimens. This technique employs instrumentation that is remote from the impacted organ and could be applied to fluid-filled abdominal components of crash-test dummies. A fluid-filled catheter (FFC) pressure-measurement device was modelled as an under-damped second-order linear system. A transfer function was defined to correct the characteristic distortion of pressure waveforms in the FFC pressure-measurement system. Linear regression analysis was employed to evaluate the accuracy of transfer function-corrected pressure measurements in impact tests of a simplified model system and of physiologically pressurised ex vivo porcine livers. Results demonstrated a very high correlation between transfer function-corrected FFC pressure measurements and reference pressures in model system impacts (R = 0.95-0.97) and in ex vivo porcine liver impacts (R = 0.91-0.96). A near one-to-one relationship between the magnitudes of the corrected FFC pressures and the reference pressures was demonstrated by calculating the slopes of the regression equations (0.821 ± 0.016 to 1.085 ± 0.005, p < 0.05). The FFC technique has the potential to be a valuable tool in future studies requiring dynamic measurements of extremely high intravascular pressures associated with impact loading of soft tissues such as the liver. Information about the relationship between pressure and injury in solid abdominal organs could be applied to improve the design of crash-test dummies.