On Airway Anesthetic Gas Analyzer

Period of Performance: 09/30/1997 - 09/29/1999


Phase 2 SBIR

Recipient Firm

Displaytech, Inc.
2200 Central Avenue
Boulder, CO 80301
Principal Investigator


Our aim is to develop an on-airway anesthetic gas analyzer capable of identifying and quantifying the five most common anesthetic agents used in surgical procedures. Since it is mounted on the patient airway and has a rapid response time, the proposed instrument is also capable of breath by breath measurement of inspired and expired anesthetic agents. The five most common anesthetic agents, desflurane, enflurane, halothane, isoflurane and sevoflurane, each have unique absorption bands in the 8-13 micromole Mid-IR region. Current anesthetic gas analyzers require a mechanical chopper because Mid-IR detectors are sensitive to the change in optical power rather than absolute power. Mechanical choppers give too much vibration, and make them too large and heavy to mount on the patient airway. We propose to develop a compact, light, inexpensive, electro- optic, 8-13 micromole chopper (non-mechanical, no moving parts, no vibration) using ferroelectric liquid crystal (FLC) technology and an innovative manufacturing method for producing low cost IR polarizers. The device will differentiate between anesthetics for increased patient safety. In addition to medical applications this shutter will also be incorporated in spectrometers for environmental monitoring, industrial monitoring, astronomy and automobile emissions testing. PROPOSED COMMERCIAL APPLICATIONS: Anesthetic monitors, emissions testing