Abstract
Full text: The methods that have been used for monitoring volatile anaesthetic agents depend on some physical property such as Density, Refractometry, Mass, Solubility, Raman scattering, or Infra-red absorption. Today, refractometry and infra-red techniques are the most common. Refractometry is used for the calibration of vaporizers. All anaesthetic agents increase the refractive index of the carrier gas. Provided the mixture is known then the refractive change measures the concentration of the volatile anaesthetic agent. Raman Scattering is when energy hits a molecule a very small fraction of the energy is absorbed and re-emitted at one or more lower frequencies. The shift in frequency is a function of the chemical bonds and is a fingerprint of the substance irradiated. Electromagnetic (Infra-red) has been the commonest method of detection of volatile agents. Most systems use a subtractive system, i.e. the agent in the sampling cell absorbed some of the infrared energy and the photo-detector therefore received less energy. A different approach is where the absorbed energy is converted into a pressure change and detected as sound (Acoustic monitor). This gives a more stable zero reference. More recently, the detector systems have used multiple narrow-band wavelengths in the infrared bands and by shape
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Russell, W J
[1]
- Royal Adelaide Hospital, SA (Australia). Department of Anaesthesia and Intensive Care
Citation Formats
Russell, W J.
Monitoring volatile anaesthetic agents.
Australia: N. p.,
2000.
Web.
Russell, W J.
Monitoring volatile anaesthetic agents.
Australia.
Russell, W J.
2000.
"Monitoring volatile anaesthetic agents."
Australia.
@misc{etde_20227154,
title = {Monitoring volatile anaesthetic agents}
author = {Russell, W J}
abstractNote = {Full text: The methods that have been used for monitoring volatile anaesthetic agents depend on some physical property such as Density, Refractometry, Mass, Solubility, Raman scattering, or Infra-red absorption. Today, refractometry and infra-red techniques are the most common. Refractometry is used for the calibration of vaporizers. All anaesthetic agents increase the refractive index of the carrier gas. Provided the mixture is known then the refractive change measures the concentration of the volatile anaesthetic agent. Raman Scattering is when energy hits a molecule a very small fraction of the energy is absorbed and re-emitted at one or more lower frequencies. The shift in frequency is a function of the chemical bonds and is a fingerprint of the substance irradiated. Electromagnetic (Infra-red) has been the commonest method of detection of volatile agents. Most systems use a subtractive system, i.e. the agent in the sampling cell absorbed some of the infrared energy and the photo-detector therefore received less energy. A different approach is where the absorbed energy is converted into a pressure change and detected as sound (Acoustic monitor). This gives a more stable zero reference. More recently, the detector systems have used multiple narrow-band wavelengths in the infrared bands and by shape matching or matrix computing specific agent identification is achieved and the concentration calculated. In the early Datex AS3 monitors, a spectral sweep across the 3 micron infrared band was used to create spectral fingerprints. The recently released AS3 monitors use a different system with five very narrow band filters in the 8-10 micron region. The transmission through each of these filters is a value in a matrix which is solved by a micro computer to identify the agent and its concentration. These monitors can assist in improving the safety and efficiency of our anaesthetics but do not ensure that the patient is completely anaesthetized. Copyright (2000) Australasian College of Physical Scientists and Engineers in Medicine.}
journal = []
issue = {4}
volume = {23}
journal type = {AC}
place = {Australia}
year = {2000}
month = {Dec}
}
title = {Monitoring volatile anaesthetic agents}
author = {Russell, W J}
abstractNote = {Full text: The methods that have been used for monitoring volatile anaesthetic agents depend on some physical property such as Density, Refractometry, Mass, Solubility, Raman scattering, or Infra-red absorption. Today, refractometry and infra-red techniques are the most common. Refractometry is used for the calibration of vaporizers. All anaesthetic agents increase the refractive index of the carrier gas. Provided the mixture is known then the refractive change measures the concentration of the volatile anaesthetic agent. Raman Scattering is when energy hits a molecule a very small fraction of the energy is absorbed and re-emitted at one or more lower frequencies. The shift in frequency is a function of the chemical bonds and is a fingerprint of the substance irradiated. Electromagnetic (Infra-red) has been the commonest method of detection of volatile agents. Most systems use a subtractive system, i.e. the agent in the sampling cell absorbed some of the infrared energy and the photo-detector therefore received less energy. A different approach is where the absorbed energy is converted into a pressure change and detected as sound (Acoustic monitor). This gives a more stable zero reference. More recently, the detector systems have used multiple narrow-band wavelengths in the infrared bands and by shape matching or matrix computing specific agent identification is achieved and the concentration calculated. In the early Datex AS3 monitors, a spectral sweep across the 3 micron infrared band was used to create spectral fingerprints. The recently released AS3 monitors use a different system with five very narrow band filters in the 8-10 micron region. The transmission through each of these filters is a value in a matrix which is solved by a micro computer to identify the agent and its concentration. These monitors can assist in improving the safety and efficiency of our anaesthetics but do not ensure that the patient is completely anaesthetized. Copyright (2000) Australasian College of Physical Scientists and Engineers in Medicine.}
journal = []
issue = {4}
volume = {23}
journal type = {AC}
place = {Australia}
year = {2000}
month = {Dec}
}