Smart Tourniquet for Acute Trauma

Abstract

Major traumatic injuries to lower limbs require tourniquet intervention in nearly 90% of cases. Overtightening and improper application result in about 23% of patients experiencing long term nerve and tissue damage. These complications significantly lower the quality of life of the patient and can be a future roadblock to rehabilitation and prosthetic implementation. The Smart Tourniquet for Acute Trauma (STAT) system that addresses these complications by automatically applying compression in response to pulsatile blood flow. Currently, all automated tourniquet systems are pneumatic while the STAT system is not. Our device seeks to capitalize on this gap in the industry and provide a portable and field ready tourniquet solution for military and civilian application. The device architecture provides the most accurate and safe tourniquet for field application due to tightening only occurring when pulse is detected, limiting the overtightening risk significantly which is not currently possible with the standard Combat Acute Tourniquets (CAT). Our tourniquet comprises a velcro cuff, inner compression band, MEMS sensor, sensor air bubble, torque motor, battery pack, and a microcontroller. The MEMS sensor is able to detect small air ripples within the bladder which occur when a pulse of blood flows through the femoral artery. To test the accuracy of our system, tubing and foam were constructed to act as a model for skin and tissue. Our testing resulted in defined peaks in signal, representing pulses as well as activation of our torque motor in response showing our systems were integrated effectively. By demonstrating key functionality of our sensing system and tightening system together, we are the first to have a mechanical tourniquet system that integrates active pulsatile flow signals to indicate tightening response.

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