Surgery – Truss – Pad
Patent
1986-02-26
1987-10-06
Cohen, Lee S.
Surgery
Truss
Pad
356 41, A61B 500
Patent
active
046975934
DESCRIPTION:
BRIEF SUMMARY
This invention relates to oximetry. It has particular application in the use of oximetry during anasthesia, particularly general anaesthesia and the intensive care of patients.
Oximetry is a technique which has been in use for a period of years for measuring blood oxygenation. It is found that, if the oxygen level in blood falls, the colour of the blood moves from the red toward the blue end of the spectrum. By comparing light absorbtion at two or more different wavelengths, for example at a wavelength in the red, and in the infra-red, the level of oxygenation of the blood may be determined. It will be understood that the term "light" is used herein to include the infra-red and ultra-violet regions of the spectrum, and should not be interpreted as being restricted to visible radiation.
Early oximetry techniques were carried out by direct measurement on the blood, normally by entering a blood vessel, for example as disclosed in U.S. Pat. Nos. 4,114,604 and 3,847,483. More recent proposals have been for non-invasive per-cutaneous techniques, for example carried out on a finger or on the soft tissue of the nose. Such techniques are proposed, for example, in European Patent Specifications Nos. 104771 and 104772.
Furthermore European Patent Specification No. 135840 discloses a per-cutaneous oximetry device adapted to be affixed to a blood-perfused portion of foetal tissue during childbirth.
Although per-cutaneous oximetric measurement is far preferable to the earlier, invasive methods, the methods proposed to date tend to be somewhat unreliable, because of interference with the measurement caused by pigmentation, changes in blood flow due to vaso-constriction and interference from ambient light.
It has now been discovered that the mucosa lining the internal surfaces of the trachea, and, particularly the oesophagus provide a particularly advantageous site for the measurement of blood oxygenation.
In accordance with a first aspect of the invention, there is provided apparatus for the in-vivo measurement of blood oxygenation levels of a patient, in particular a human patient, which apparatus comprises an elongate probe adapted to pass into the trachea or, preferably, the oesophagus, means associated with the probe for illuminating the internal surface of the trachea or oesophagus, means for observing light reflected from the internal surface of the trachea or oesophagus and means for determining from the reflected light the degree of oxygenation of blood in the internal surface of the trachea or oesophagus.
In accordance with the second aspect of the invention, there is provided a probe for the measurement of oxygenation of the internal surface of the trachea or oesophagus, comprising an elongate body portion, means on the body portion for emitting light to illuminate the internal surface of the trachea or oesophagus, means for receiving light reflected from the internal surface of the trachea or oesophagus and means for connecting the light receiving means to means for detecting from the reflected light signal the degree of oxygenation of blood in the internal surface of the trachea or oesophagus.
As indicated above, the probe in accordance with the invention may be utilised in either the oesophagus or the trachea, but it is particularly preferred to utilise an oesophageal probe. The oesophagus is a particularly preferred site, not only because it is well-perfused with blood, is substantially non-pigmented, is free of ambient light, and not prone to changes in blood perfusion associated with peripheral vaso-constriction, it is also found that it is particularly convenient and easy to retain an oesophageal probe in place during operations in which general anaesthesia is employed. Furthermore, an oesophageal probe in accordance with the invention can preferably include various lumens, pressure-measuring devices and the like for example as described in European Patent Specification No. 0050983. Because the oesophageal probe is preferred, the invention will be illustrated hereinafter with respect to an oesophageal pr
REFERENCES:
patent: 3136310 (1984-06-01), Meltzer
patent: 3461856 (1969-08-01), Polanyi
patent: 3674013 (1972-07-01), Polanyi
patent: 3690769 (1972-09-01), Mori
Yee et al, "A Proposal Miniature . . . Tip", IEEE Trans. Biom. Eng., vol. 24, No. 2, Mar. 1977, pp. 195-197.
Evans John M.
Wise Colin C.
LandOfFree
Method and apparatus for measuring blood oxygen levels does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Method and apparatus for measuring blood oxygen levels, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Method and apparatus for measuring blood oxygen levels will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2111747