Method and apparatus for detection of venous air emboli
US5533512A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Mar 18, 1994 |
| Grant date | Jul 9, 1996 |
| Priority date | — |
| Expiry date | Mar 18, 2014 |
Classification
- Technology area (CPC A)Human Necessities
- CPC primaryA61B5/083
- WIPO fieldMedical technology
- WIPO sectorInstruments
Abstract
Concomitant measurement of EtCO.sub.2, EtN.sub.2 and (FiO.sub.2 -FeO.sub.2) concentrations are used to detect a VAE. In a respiratory gas monitoring system, continuous measurements of end-tidal carbon dioxide, end-tidal nitrogen and the difference between inspired and expired oxygen concentrations are averaged using a predetermined time period and stored as historical data. Periodically, a present value of each of these concentrations is compared to its respective historical average for a predetermined time period. If the following conditions are met, the device signals the presence of a venous air embolism: 1) a decrease in the EtCO.sub.2 concentration of 1.5 mm Hg; 2) an increase in the FeN.sub.2 concentration of 0.03 vol %; and 3) a decrease in the difference between the inspired oxygen concentration and the expired oxygen concentration of 0.20 vol %.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.