Respiratory inductive plethysmography band transducer

Abstract

A device for reliably and non-invasively measuring respiration rates and effort by encircling the patient's chest with a device having a large section of inelastic belt attached to a small section of elastic material. The elastic material having two magnetic tapes with wire windings thereon proximate each other with an insulation material therebetween. The wire windings are electrically connected to each other. The magnetic tapes have opposite ends attached to the elastic material such that when the elastic material expands and contracts the wire windings move relative to each. A toroidal transformer is connected to the wire windings. When a carrier signal is introduced to the transformer and the magnetic tapes move relative to each other on the elastic material when the patient breathes a mutual inductance in the wire windings modulates the carrier signal and thus measures the expansion and contraction of the patient's chest which is directly related to the patient's respiration rate. The electronics connected to the device for monitoring respiration also measures belt shifting for diameter changes during monitoring by measuring the central amplitude during a breath cycle and comparing the initial belt diameter conditions to later conditions. The electronics can then compensate for amplitude variations in the signal caused by belt shifting which may be confused with shallower breathing in uncompensated devices.

Dependencies are inferred from the claim text.