Respiration rate monitor
US5143078A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Sep 29, 1989 |
| Grant date | Sep 1, 1992 |
| Priority date | — |
| Expiry date | Sep 29, 2009 |
Classification
- Technology area (CPC A)Human Necessities
- CPC primaryA61B7/003
- WIPO fieldMedical technology
- WIPO sectorInstruments
Abstract
A monitoring system for providing an accurate indication of a patient's respiration rate. The system is effective in eliminating or significantly reducing the effects of heart sounds and ambient noise. The system comprises means for obtaining a first signal waveform containing components corresponding to the patient's breath sounds, as well as components corresponding to heart sounds and ambient noise. The signal is passed through a digital bandpass filter having a passband selected to remove heart sounds and ambient noise to produce a second waveform. From the second waveform the total energy is computed of a portion of the signal within a moving window of predetermined length. The resulting energy envelope signal is smoothed and then high-pass filtered by removing the average DC value of the signal over a predetermined preceding time interval. Respiration is detected by identifying significant, positive-going zero crossings of the resulting signal through a band about zero. The zero-band threshold used to obtain this waveform can be controlled by the operator or pre-set for a particular sensitivity.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.