Surgery – Diagnostic testing – Measuring fluid pressure in body
Patent
1999-01-19
2000-11-14
Lacyk, John P.
Surgery
Diagnostic testing
Measuring fluid pressure in body
600547, A61B 500
Patent
active
061463361
DESCRIPTION:
BRIEF SUMMARY
SPECIFICATION
The invention relates to a method and to a device for measuring an intra-cranial pressure in the skull of a test subject.
The intra-cranial pressure, i.e. the pressure within the skull of a human, is measured in many ways, all the measuring methods used at the moment being based on the fact that the skull, regarded as an enclosed container, must be opened by means of trepanning, in order to be able to insert an appropriate measurement receiver. The outlay on this is considerable, and probably needs no further explanation. In addition, the measurement results are only of restricted reliability, as the point of application of the drill hole, the type of measurement receiver itself and its condition which changes through time, and other peripheral conditions, can considerably influence the measurement results. Non-invasive measurements to date have been exclusively carried out on children, whose fontaelle is not yet closed, so that the scalp movement in this area, which is in fact a measurement of the fluctuations in pressure, can be measured. An atromatic measurement of the intra-cranial pressure by taking a so-called "capacitive pulse wave" is known from Wiener klinische Wochenshrift, Volume 18, 28 September 1990, pages 543-547. It has however become apparent that the known method of measurement provides considerable difficulties as regards its reproducibility.
As further possibilities of non-invasive measurement of the intra-cranial pressure, there are described measurement of sound transmission through the skull (Annals of Biomedical Engineering, Volume 23, pages 720,727,1995), measurement of the thickness of the meninges (Neuroscience Letters 198, pages 68-70, 1995) or also a type of volumetric measurement via ultrasound (NASA Tech. Briefs, June 1994). All these known methods are however complex and their results offer little satisfaction.
The object underlying the invention is to indicate a method and a device for measuring the intra-cranial pressure, which in a simple way permits an adequately accurate determination of the intra-cranial pressure.
This object is achieved by a method for measuring the intra-cranial pressure in a skull of a test subject, which comprises the following steps: such a way that they have electrical contact with the skull. A chronological progress of an electrical resistance, particularly of a complex resistance, i.e. an ohmic resistance, and of a capacitance between the at least two electrodes, is obtained as an electrical signal. An extreme value following the maximum blood pressure corresponding to a systole, with a substantially uniform delay of the electrical signal is determined as a first amplitude value. A second amplitude value is obtained from the electrical signal, where this has either a maximum or a turning point for the first time after the first amplitude value. A third amplitude value is obtained from the electrical signal at a point in time later than the second amplitude value. A standardized pressure measurement value is obtained from the amplitude values for further use. An essential point of this method resides on the one hand in the fact that in a particularly simple way and by means of previously known methods, a measurement is undertaken which may be carried out at any time by non-specialist personnel. Whereas nowadays in practical medicine measurement of brain pressure is usually carried out epidurally by means of miniaturized pressure probes, i.e. can be carried out only by doctors, the method according to the invention can be carried out by any medical orderly, even in an ambulance. The measurement values obtainable by means of the method according to the invention can be further used in many ways. In particular, it is possible to trace alterations in the brain pressure over lengthy periods of time, without the test subject or patient being stressed thereby.
A quotient can be formed from the second amplitude value and the third amplitude value, in order to obtain the standardized pressure measurement value. In this way it is ensured tha
REFERENCES:
patent: 4425920 (1984-01-01), Bourland et al.
patent: 4564022 (1986-01-01), Rosenfeld et al.
patent: 4660568 (1987-04-01), Cosman
patent: 4688577 (1987-08-01), Bro
patent: 4893630 (1990-01-01), Bray, Jr.
patent: 4971061 (1990-11-01), Kageyama et al.
patent: 4984567 (1991-01-01), Kageyama et al.
patent: 5074310 (1991-12-01), Mick
patent: 5117835 (1992-06-01), Mick
patent: 5617873 (1997-04-01), Yost et al.
Lacyk John P.
Marmor II Charles
Nicolet Biomedical Inc.
LandOfFree
Method and device for measuring the intra-cranial pressure in th 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 device for measuring the intra-cranial pressure in th, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Method and device for measuring the intra-cranial pressure in th will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2060868