Impedance pneumography
US6015389A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Jun 5, 1998 |
| Grant date | Jan 18, 2000 |
| Priority date | — |
| Expiry date | Jun 5, 2018 |
Classification
- Technology area (CPC A)Human Necessities
- CPC primaryA61B5/086
- WIPO fieldMedical technology
- WIPO sectorInstruments
Abstract
The invention concerns a method and apparatus for monitoring respiratory condition by impedance pneumography. An electrical signal is applied at a plurality of frequencies to a human subject by way of a first pair of spaced electrodes applied to the trunk of the body, whilst the resulting electrical signal is monitored at the plurality of frequencies at different points on the body by way of a second pair of spaced electrodes. From the resulting electrical signal a measure of the impedance of a part of the body at the plurality of frequencies is obtained, and a difference signal representing the impedance change with frequency is calculated. The difference signal is normalized with respect to a signal representative of the impedance measure itself at one or more frequencies, thereby suppressing the effect of those impedance signal components--such as movement artifact--whose frequency dependent change is substantially proportional to the impedance signal value. The invention improves the reliability of impedance pneumography, especially when employed in situations in which it is difficult to restrict subject movement, such as during sleep. It has particular application in neonatal …
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.