Abstract 18257: A Novel Portable Polyvinylidene Fluoride Based Sensor for Detection of Hemorrhage

Abstract

Introduction: Hemorrhage (Hem) is one of the leading causes of mortality from trauma, and continuous monitoring for Hem using techniques such as traditional BP, especially in field conditions, poses significant challenges. We have built a portable low-powered noninvasive sensor for continuous vascular tone monitoring to detect significant Hem as an alternative to BP monitoring. The sensor, made of polyvinylidene fluoride (PVDF) material, can sense and record changes in the mechanical properties of arteries due to peripheral vasoconstriction caused by Hem. Methods: Nine pigs underwent Hem by femoral artery bleeding. Systolic arterial pressure (SAP) was used to select 16 instances of significant hemorrhage (SAP>85mmHg pre-Hem and >10mmHg drop in SAP post-Hem). The PVDF signal was measured from the animal’s distal forelimb. A piecewise linear estimation of the PVDF signal was computed using a newly developed Taut String algorithm such that the error was <4% of the signal amplitude. The number of pieces in each period was used as a complexity score (CS) to detect Hem. Results: Arterial BP and the CS derived from the PVDF signal for one subject (Fig), as well as snapshots from the PVDF signal demonstrating morphology changes are shown. Maximum separation between pre- and post-Hem CS was achieved by a threshold of 5.5; 14 instances (87.5%) transitioned from CS≥6 to 5 within 5 minutes of the onset of HS (t0) while the remaining 2 instances transitioned from CS=5 to 3. The average detection delay was 1.95±1.2 min. These changes corresponded to >10mmHg decrease in SAP from baseline. CS improved during subsequent resuscitations. Conclusions: The proposed low-powered portable sensor captures continuous vascular tone and can be used to detect significant Hem in a continuous manner that may offer diagnostic and therapeutic guidance as an alternative to traditional intermittent BP measures. The results indicate that the derived CS can effectively separate the signals pre- and post-Hem.