Design and Analysis of a Clinical Pressure Cuff Algometer, Compatible with an fMRI Machine.

Abstract

Chronic pain affects both adolescent and adult Canadians. To study the effect of social rejection on pain management in adolescents with chronic pain, an algometer can be used in conjunction with functional Magnetic Resonance Imaging (fMRI) to measure brain activity in real time. The algometer uses an automated pneumatic control system that follows a customizable pain schedule, controlling the amount of airflow in and out of a pressure cuff wrapped around a human participant's thigh. Plastic components allow compatibility with an fMRI environment. Measurable pain stimuli allow repeatable pressure schedules to be administered with a standard deviation between trials of 300 Pa (2.25 mmHg). A Failure Mode Effects Analysis was used to reduce participant, researcher and facility harm, with multiple safety features incorporated into the design. Through the analysis of medical standards and studies, the algometer is shown to be biologically safe to use on research subjects within the suggested usage parameters of a maximum pressure of 42.6 kPa (320 mmHg) and a pressure application period of up to one hour. This makes it feasible for research studies using fMRI machines.