DE4447825C2 - Non-invasive oxygen saturation level in haemoglobin measurement - Google Patents

Abstract

The apparatus for oxygen saturation measurement in human organs and blood vessels uses a sensor with two or more light sources operating at different wavelengths, preferably 660 and 940 nm, and a receiver measuring transmitted and reflected light from oxygen-binding haemoglobin and delivering a signal to a pulse-oximeter and subsequently to a display. The measurement sensor (MS) is associated with a further sensor in order to locate organs and blood vessels. The two sensors are combined in a common probe.

Description

The invention relates to an arrangement for determination oxygen saturation in human vessels and Or ganen in accordance with the preamble of claim 1 type.

From the article by YEE, Sinclair; SCHIBLI, Eugen; KRISHNAN, Vedavalli: A Proposed Miniature Red / Infrared Oximeter Suitable for Mounting on a Catheter Tip. In: IEEE Transactions on Biomedical Engineering, 1977, Vol. BME-24, No. 2, pp. 195-197 is known to be oxygen is in the blood of human vessels using pulse oximes to determine trie. There are usually two Light sources, preferably light of the wavelength of 660 nm (red area) and 940 nm (infrared loading rich), e.g. B. diodes, and a receiver who uses the emitted and from the tissue reflect recorded or transmitted light waves. The from the recipient, e.g. B. a photo detector Light is sent as an electrical signal to a pusoximeter forwarded. The pulse oximeter evaluates these signals and shows a the present oxygen content proportional measured value on a with the pulse oximeter connected display device.  

To get to the measuring point, Kathe artificial and natural body openings brought the measurement site. There are light guides in the catheter the light sources and the receiver provided, each because end at the distal end of the catheter.

When measuring the right heart catheter, e.g. B. after a Heart attack, heart function needs to be monitored. This is because of the large diameter of the catheter one of the large veins (Vena Subclavia / Vena Jugularis) dotted according to Seldinger technology. about a balloon catheter is used for this artificial access washed into the bloodstream (Swan-Ganz catheter). At the Work against the bloodstream is known for this Techniques to use.

During the puncture and the advance in the vessels there is damage or perforation of the vessel wall, especially with branches and curvatures, as well as latent along the vessel wall. Furthermore threatens mechanically causing movement of the catheter gentle detachment of deposits on the vessel walls can lead to thrombosis and embolism.

In addition, cardiac irritation occurs, the heart rhythm disorders and when the catheter comes into contact with the heart Muscles can cause ventricular fibrillation great care sometimes not therapeutically mastered is cash. To avert a threatening heart verse The vitally threatened patient becomes set of a defibrillator given electric shocks, which besides the vegetatively adverse effects no physical stress.  

For the measurement itself it is necessary that the Catheter position during the measurement not due to movements is disturbed in order to falsify the measurement result exclude and to ensure a reproducible measurement guarantee. But just near the striking With this method, there are many unwanted effects Falsifications of the measurement result, because the strong pressure resulting from cardiac activity fluctuations of the catheter during the measurement do not ru can hold. A reproducibility for ver equal measurements is therefore also difficult to achieve.

The location of the catheter at the measurement site follows under X-ray exposure or in such a way that blood pressure via lumens in the catheter extracorporeal pressure transducer is measured. Based on pressure curves obtained in this way and their correct interpretation the position of the catheter can be determined. This process is complex and requires a lot of work experience.

Although the catheter with the measuring sensor for the Measurement also through the esophagus near the pul monal artery, but here is one Localization of the pulmonary artery with the necessary Accuracy practically impossible because of the treating Doctor There are no indications of which number there abundant, oxygen-rich blood-bearing ar teries the oxygen content is actually measured. Such a measurement result allows the patient to be treated Not a doctor, undoubtedly diagnostics and accordingly to practice sound therapy. Compare with others Measurement results using medical experience therefore, values cannot be carried out either.  

An external measurement of the oxygen content of tie fer located vessels and organs is known with Measuring sensors currently not feasible.

For an arrangement that allows, without high-risk arterial or venous accesses to the Sauer substance content of vessels, especially pulmonary artery, as well as deep-lying vessels or organs measure, there is considerable need.

DE 40 31 320 A1 and DE 42 43 142 A1 each because an arrangement for the analysis of body fluids known in human vessels and organs that however, do not interact with a pulse oximeter.

The invention has for its object an arrangement for the determination of oxygen saturation in humans vessels and organs according to the in the preamble of Claim 1 specified type to create the Mes enables the oxygen content in vessels without an invasive procedure (puncture) on the patient to have to take. Preferably, the range of Measuring location of the vessel to be selected for the measurement with the entire arrangement low-risk, reproducible and securely localizable and the measuring point on one Display device can be displayed.

This task is characterized by the characteristics of claim 1 in conjunction with the preamble features solved.

The subclaims form advantageous further developments the invention.

According to the invention, the measuring sensor has two um each an angle symmetrically pivotable to a vertical axis Beam paths of two light-generating and transmitting  Systems based on an intersection on the Cut the vertical axis and at least the common one Is assigned to the recipient. As a result, are deeper Vessels selectable and their oxygen content measurable.

Here it is advantageous if each light-generating and light-guiding system adjustable and fixed to each other adjustable a lens, lenses and light sources in has a tube, the tube in the area of Objective has an ankle, as well as the receiver in a pedestal arranged symmetrically to the vertical axis steer receiver housing parallel to the high axis are arranged. One red and one infra red light generating and guiding system is in each case ligament ankle of the receiver housing to the vertical axis pivoted and by adjusting means in each adjustable at an angle to the vertical axis and by means of a clamp medium noticeable. After all is the light generator one and the leading systems as well as the recipients flexible cover assigned to external light shielding net.

When measuring oxygen saturation according to the Erfin dung from all parts of the body invasive procedures can be performed shunned so that the physical and psychological secondary burden on the patient is significantly reduced. Ande re risk factors such as heart irritation or perforations, by the invention Arrangement avoided.

According to an embodiment of the invention Measuring sensor for the localization of a selectable vessel or organ another measurement sensor assigned. The Measuring sensor and the further measuring sensor form a common one  manageable unit. The measuring sensor is there formed by a sonography transmitter / receiver.

Ultrasound emitting ultrasound Sender / receiver becomes an unadulterated reproducer availability of the measurement results, since by means of the Ultrasound waves clearly locate the measuring point bar and therefore all measurements are exclusively from the actual oxygen content in the blood of the beamed vessel or organ depend on the patient and the measurement result is not the wrong choice Measuring points is influenced. The invention order also ensures monitoring of Measuring point during the measurement.

Adverse disturbances for the measurement of the oxygen hold in the desired vessel or organ due to Heartbeats or blood flows are largely gone closed.

According to, another embodiment of the invention the light sources and the receiver can be detached with the Sono graphic transmitter / receiver connected, or is the Sono graphic transmitter / receiver with the light sources and the Receiver firmly connected.

Further features of the invention result from the Un dependent claims.

The invention is based on one in the Drawing more or less shown schematically Described embodiment. The individual shows

Figure is a representation of the arrangement according to the invention with a measuring sensor for external use dung.  

An embodiment of a measuring sensor MS for the external, non-invasive measurement of the oxygen content of lower-lying measuring locations is evident from the figure. A receiver housing 32 has symmetrical to the vertical axis y at an eccentric distance ankles 33 and 33 ', in each of which a tube 31 or 31 ' is pivotally mounted to the vertical axis y.

On each tube 31 , 31 ', tabs 34 and 34 ' are provided at the ends opposite the ankles 33 and 33 ', in which threaded nuts 35 and 36 are articulated. The threaded nuts 35 and 36 each have left-hand and right-hand threads, in which the threaded spindles 37 and 38 of an adjusting screw 39 engage in order to change the angular position of the tubes 31 , 31 'to one another.

The tube 31 shown in section in the figure has in the area of the ankle 33 a lens 50 , consisting of a plano-concave lens 51 arranged at the outlet ends of the tube 31 and a plano-convex lens 52 lying deeper in the tube 31 and having a larger diameter. The plane sides of the plano-concave lens 51 and the plano-convex lens 52 face each other and are arranged in the tube 31 in an adjustable version. On the convex side of the plano-convex lens 52 are at least two lenses 60 and 61 in a likewise adjustable mount in eccentric arrangement to the optical axis of the lens 50 .

The optical axis of the lens 60 is a red light source 70 and the optical axis of the lens 61, a second red light source 71 allocated such that there is 60 and 61 and the telecentric lens 50 from forming beam path between the lenses. The objective combines the beam paths of objectives 60 and 61 and images them collinearly to infinity. The tube 31 'contains the same optical arrangement as the tube 31 described above, but infrared light sources are provided as light sources. Each tube 31 and 31 'forms a light-generating and transmitting system for red light or infrared light.

To shield external light, a flexible cover 30 made of opaque material is assigned to the outlet or inlet openings of the light-generating and conducting systems or the receiver housing 32 .

In the receiver housing 32 , a receiver 80 of corresponding spectral sensitivity is provided eccentrically to the vertical axis y, the sensitive maxima of which are oriented approximately parallel to the vertical axis y.

The bundles of rays emitted by the light sources 70 and 71 and projected with the objectives 60 and 61 and the objective 50 each at the same angle alpha to the vertical axis 31 and 31 'intersect the downwardly extended vertical axis y at the intersection SP. By adjusting the adjusting screw 39 , the angle alpha of the beam paths of both light-generating and transmitting systems can be adjusted such that the intersection SP of the two beam paths can be adjusted along the vertical axis y.

For measuring the oxygen content of a deeper tissue the vessel or organ lying there will be the arrangement flat with the long side of the cover on the skin applied so that the intersection point SP lies in the tissue.

The receivers 80 detect the reflected portion of the light from both light-generating and transmitting.

Systems and give this as an electrical signal to the Pulse oximeter further.

By turning the adjusting screw 39 , the intersection point SP along the vertical axis y can be localized to a vessel or organ located in this area and the oxygen saturation can be measured. The drive of the thread despindel can also automate the localization process of a measuring location with a motorized, actuated or controllable actuator from a console, z. B. with a program-controlled step motor. In a miniaturized version, a piezoelectric actuator can also perform the pivoting movement of the light-generating and guiding systems.

Tubes 31 and 31 'of the light-generating and guiding systems can be fixed in the set position with a fastening device 40 . The fastening device 40 consists of two brackets 41 and 41 'which are articulated at one end to the tube 31 or 31' and have scaling, in which slots 42 and 42 'are made, in which a clamping screw 43 with a corresponding lock nut is arranged.

The measuring sensor MS can be seen in the figure of the overview for the sake of clarity, Transmitter / receiver with beam aligned to the vertical axis direction to be assigned in order to locate the measurement location taping.  

LIST OF REFERENCE NUMBERS

MS measuring sensor
y vertical axis
alpha angle
SP intersection
DS sonography transmitter / receiver

30

cover

31

.

31

'' Tube

32

receiver housing

33

.

33

'' Ankles

34

.

34

'' Tabs

35

nuts

36

nuts

37

screw

38

screw

39

adjusting screw

40

fastening device

41

.

41

' Hanger

42

.

42

'Slots

43

clamping screw

50

lens

51

plano-concave

52

plano-convex lens

60

lens

61

lens

70

red light source

71

red light source

80

receiver

Claims (7)

1. Arrangement for determining the oxygen saturation in human vessels and organs with a measuring sensor (MS) with at least two light sources of different wavelengths and with at least one receiver ( 80 ) which transmitted the oxygen particles bound to the hemoglobin in the irradiated vessel or organ and receives light reflected from the surrounding tissue and forwards it as an electrical signal to a pulse oximeter for evaluating the measurement result and output on a display device, characterized in that the measuring sensor (MS) has two angles (alpha) symmetrical to a vertical axis ( y) has pivotable beam paths of two light-generating and transmitting systems which intersect at an intersection (SP) on the vertical axis (y) and to which at least the common receiver ( 80 ) is assigned. 2. Arrangement according to claim 1, characterized in that a light source is light with a wavelength of 660 nm and the other light source using light with a wavelength of 240 nm. 3. Arrangement according to claim 1 or 2, characterized in that each light-generating and light-conducting system by adjusting means ( 39 ) is adjustable and in the angle (alpha) by means of clamping means ( 43 ) that the one system red and the other System generates and guides infrared light, a system each has a lens ( 50 ), further lenses ( 60 , 61 ) and light sources ( 70 , 71 ) in a tube ( 31 , 31 '), each tube ( 31 , 31 ') in Area of the objective ( 50 ) is provided with an ankle joint ( 33 , 33 ') that the receivers ( 80 ) are arranged in a receiver housing ( 32 ) pointing symmetrically to the vertical axis (y), the ankle joints ( 33 and 33 ') pointing towards the receiver to the vertical axis (y) are arranged so that the system is connected to the ankle of the tube ( 31 or 31 ') and is pivotally mounted in the ankle ( 33 and 33 ') of the receiver housing to the vertical axis (y), and that the light generating and guiding systems as well as de n receivers ( 80 ) is assigned a cover ( 30 ) for external light shielding. 4. Arrangement according to one of the preceding claims, characterized in that the measuring sensor (MS) to locate a selectable vessel or Organs another measurement sensor (DS) is assigned and handle both measurement sensors as one bare unit are formed. 5. Arrangement according to claim 4, characterized in that the measuring sensor (MS) has an Ul ultrasound transmitter emitting ultrasonic waves / - Receiver (DS) is assigned. 6. Arrangement according to claim 5, characterized in that the measuring sensor (MS) and the sonography Transmitter / receiver (DS) detachably connected to each other they are.   7. Arrangement according to one of the preceding claims, characterized in that the signals of the measuring sensors (MS, DS) and the measured Sauer Result proportional to substance content on a moni are representable.