A medical device for measuring blood flow through a blood vessel of a mammal includes a conductive elastomer having a variable resistance. A frame is at least partially surrounding at least a portion of the conductive elastomer, the conductive elastomer is suspended within the frame. A mechanical amplification element is slidably engaged to the conductive elastomer, the mechanical amplification element being configured to slide within the frame and to contact skin of the mammal over the blood vessel when the frame is positioned over the blood vessel, the mechanical amplification element being configured to be displaced when the artery pulsates and changes the resistance of the elastomer.