Surgery – Truss – Pad
Patent
1992-05-26
1994-04-05
Cohen, Lee S.
Surgery
Truss
Pad
128718, 12820514, 12820515, A61B 508
Patent
active
052995798
DESCRIPTION:
BRIEF SUMMARY
FIELD OF THE INVENTION
This invention relates to apparatus for non-invasively examining and measuring pulmonary function parameters of a patient. The apparatus has been developed primarily for measuring the pulmonary blood flow or perfusion, and simultaneous measurement of the carbon dioxide removal from the lungs and the pulmonary volume for carbon dioxide is possible. A further feature of the apparatus according to the invention makes it possible also to measure the oxygen consumption, the respiratory quotient and the oxygen saturation of the mixed venous blood.
BACKGROUND OF THE INVENTION
The pulmonary blood flow or pulmonary perfusion is the rate of flow of the blood passing through the lungs in gas-exchange relation with the respiratory gas contained in the alveoles of the lungs. It is to be noted that this rate of flow is not neccessarily equal to the rate of flow of the blood discharged from the heart, because defects in the blood circulation may result in less than the entire cardiac output reaching the lungs. Moreover, it is not neccessarily equal to the blood flow actually passing through the lungs, because defects of the lungs, such as clogged or collapsed alveols, may result in less than the total blood flow through the lungs coming into gas-exchange contact with the respiratory gas.
Accordingly, the pulmonary blood flow is a measure of the effectiveness of the pulmonary function and obviously is important to examine and measure in patients having an impaired pulmonary function and/or an impaired cardiac function. Of particular interest is the measurement of the pulmonary blood flow in patients having both an impaired pulmonary function and an impaired cardiac function, because many therapeutic methods for improving the pulmonary function impair the cardiac function.
Several different methods for determining the pulmonary blood flow have previously been proposed and have also been practised to some extent. These previously known methods are very complicated and time-consuming, however, and for that reason are not practically useful for clinical purposes. Besides, some of them are invasive. Certain of the previously known methods require that the patient be supplied with respiratory gas that includes non-physiological gases.
SUMMARY OF THE INVENTION
Accordingly, the object of the present invention is to provide simple and accurate apparatus for non-invasively measuring the pulmonary blood flow and other pulmonary function parameters of a patient without supplying non-physiological gases to the patient.
The characterising features of the invention are set forth in the accompanying claims.
BRIEF DESCRIPTION OF THE DRAWINGS
The invention will be described in greater detail hereinafter with references to the accompanying drawings, in which:
FIG. 1 is a diagrammatic illustration by way of example of an embodiment of an apparatus according to the invention;
FIG. 2 and FIG. 3 are diagrams referred to in connection with the description of the mode of operation of the apparatus according to the invention which follows.
DETAILED DESCRIPTION OF THE DRAWINGS
As shown diagrammatically and by way of example in FIG. 1, an embodiment of an apparatus according to the invention comprises a reservoir 1 of variable volume. In the illustrated exemplary embodiment the reservoir is a bellows, one end wall 1a of which is fixed, while the other end wall 1b is movable in accordance with the volume variations of the reservoir 1. The maximum volume of the reservoir may be 3-5 liters.
Connected to the reservoir 1 are an inhalation conduit 3 provided with a one-way valve 6 and an exhalation conduit 2 provided with a one-way valve 5, the inhalation conduit 3 and the exhalation conduit 2 being interconnected through a common conduit 4, which is connectable, in a suitable conventional manner not illustrated, to the respiratory tract of the patient whose pulmonary function is to be examined. The two one-way valves 5 and 6 are arranged such that they permit flow of gas to the connected patient only through the inhala
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Gedeon Andras
Mebius Claes
Casler Brian L.
Cohen Lee S.
MINCO AB
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