System and method of determining breathing rates from oscillometric data

Inventors

Badee, Vesal • Ross-Howe, Sara • Haid, Josh • Amzil, Lamiaa • Morun, Cezar • Shin, Bonghun

Assignees

Cloud Dx Inc

Abstract

A system and method for determining the breathing rate of a patient using only an oscillometric device as the physiological sensor. Here, the oscillometric device is mounted on a patient's limb, and oscillometric pulse waveforms are obtained as the device's cuff deflates, thus obtaining pulse wave signals and artifact signals over multiple patient breaths. A computer processor analyzes these signals, and removes artifacts according to various algorithms. The resulting signal can be viewed as containing both an amplitude modulated envelope of pulse waves (AM signals) and a frequency modulated sequence of pulses at various time intervals (FM signals). The main harmonics of the AM and FM signals both contain breathing rate data, and system accuracy can be improved by comparing the AM harmonics with the FM harmonics. The final breathing rate data, often a function of the AM and FM harmonics, is output or stored in memory.

Core Innovation

The invention automatically determines a breathing rate of a patient using an oscillometric device mounted on a limb of the patient to obtain oscillometric type pulse waveforms. The pulse waveforms are analyzed to determine artifact-free regions and to produce edited pulse waveforms. The edited pulse waveforms are further analyzed to determine AM envelope signals and FM between-pulse-time signals.

Main harmonics are determined from the AM envelope signals and from the FM between-pulse-time signals. An AM envelope main harmonic of the AM envelope signals and an FM between-pulse-time main harmonic of the FM between-pulse-time signals are determined and compared. In response to the AM envelope main harmonic and the FM between-pulse-time main harmonic being within a predetermined limit of each other, a value is calculated from a function comprising the AM envelope main harmonic and the FM between-pulse-time main harmonic.

The calculated value is then recorded or output as the breathing rate of the patient. The breathing-rate value is computed using a function that includes main harmonics from both AM envelope and FM between-pulse-time representations.

Claims Coverage

The partial content provides two independent claims: a method claim and a system claim. Both claims share four main inventive features: artifact-free editing of oscillometric pulse waveforms, derivation of AM envelope and FM between-pulse-time signals, extraction of AM and FM main harmonics, and calculation of a breathing-rate value when the AM and FM main harmonics are within a predetermined limit of each other.

Across both independent claims, the inventive coverage centers on editing oscillometric pulse waveforms into artifact-free regions, extracting AM envelope and FM between-pulse-time signals, determining respective main harmonics, and computing, recording, or outputting the breathing-rate value when the AM and FM main harmonics agree within a predetermined limit.

Stated Advantages

Documented Applications