Surgery – Diagnostic testing – Cardiovascular
Reexamination Certificate
1999-09-28
2001-04-10
O'Connor, Cary (Department: 3736)
Surgery
Diagnostic testing
Cardiovascular
C600S310000, C600S495000, C600S322000
Reexamination Certificate
active
06213952
ABSTRACT:
FIELD OF THE INVENTION
This invention is generally in the field of non-invasive optical measurement techniques for measuring blood parameters and relates to an optical device for measuring blood-related parameters utilizing a finger holder.
BACKGROUND OF THE INVENTION
Non-invasive techniques for measurement of various blood parameters, such as blood oxygen saturation and the concentration of substances contained in the blood, have become very popular, since they advantageously do not require the withdrawal of a blood sample from a patient's body. Optical monitoring techniques of the kind specified typically utilize the detection of light transmitted or reflected from the location on the patient's body under measurement. Most of the known techniques utilize a measurement optical device or probe, designed in a manner to be attached to the patient's finger, which includes an optical assembly for irradiating the finger with light and detecting its light response.
U.S. Pat. No. 5,810,723 discloses an apparatus for the non-invasive monitoring of a patient's carboxyhemoglobin level. The patient breathes oxygen to saturate his blood hemoglobin prior to detection. The apparatus utilizes a clamp with arms which hold the patient's finger: one arm supports a light emitting source and the other supports a detector. A microprocessor controls the measurements and processes the detected signals.
U.S. Pat. No. 5,638,816 and its continuation, U.S. Pat. No. 5,860,919, disclose an apparatus for the non-invasive monitoring of blood parameters by applying pressure to the patient's finger, thus inducing an active pulse therein. The induced change of blood volume enables a better signal-to-noise ratio to be obtained.
U.S. Pat. No. 5,782,757 discloses a measuring devices in the form of disposable, folded adhesive sensors with optics embedded therein. The probe is designed so as to fit comfortably onto a patient's fingertip.
All the conventional devices of the kind specified are aimed at measuring enhanced optical pulsatile signals caused by the changes in the volume of the blood containing medium (finger). It is known that a regular optical pulsatile signal is typically 2-3% of the total transmission. The above devices are capable of obtaining the enhanced pulsatile signal that reach 8-10% of the total light transmission intensity. This enhancement of the natural pulsatile signal is a boundary of all conventional techniques of the kind specified.
A different technique is disclosed in co-pending application PCT/IL 99/00331, assigned to the assignee of the present application, where the measured signals are not pulsatile. This is an occlusion based technique, according to which a state of blood cessation is created in a medium under measurement and measurements are taken during this state. This enables to obtain significantly enhanced light response of the medium, as compared to that of the previously described techniques dealing with the pulsatile signals. To create such a state of blood cessation, over-systolic pressure should be applied to the patient's finger at either location upstream of the area under measurement, with respect to the direction of normal blood flow. None of the conventional probes is suitable for this purposes.
SUMMARY OF THE INVENTION
There is accordingly a need in the art to further improve non-invasive measurements of blood parameters, by providing a novel optical measurement device utilizing a finger holder.
It is a major feature of the present invention to provide such a device which is capable of providing the desired substantially stationary position of the finger during measurement, whilst applying over-systolic pressure to the finger.
It is a further feature of the present invention to provide such a device whose dimensions are adjustable to the finger of a specific patient.
The present invention takes advantage of the fact that measurements taken during the state of blood cessation allow for a significant increase of the blood-related signals, as compared to those taken during the state of normal blood flow. The main idea of the present invention is based on the following. To create a state of blood cessation within a patient's organ, over-systolic pressure should be applied thereto. Measurements are taken at a location downstream of that where the over-systolic pressure was applied with respect to the direction of normal blood flow. The measurement device, according to the invention, utilizes a finger holder coupled to a control unit. The finger includes a measurement unit and pressurizing assembly, which are spaced-apart from each other and are coupled to each other through a substantially rigid connector engaging the finger along its middle phalanx and proximal intephalangeal joint.
The provision of the rigid connector is associated with the following. The occlusion-based measurements are non-volumetric, the changes in volume of blood in the finger portion under measurements being undesirable for such measurements. However, it is a natural tendency of the finger under pressure to fold at the proximal intephalangeal joint, thereby causing undesirable changes in blood volume. By providing a substantially rigid support for the finger at the region of the middle phalanx during measurement, such undesirable folding can be avoided.
Generally, the measurement device may be associated with any other suitable patient's organ, such as his hand or wrist. If the patient's hand is considered, the rigid connector engages the patient's arm to prevent its folding at the elbow joint. It is more practical, however, to apply the device to the patient's finger.
The measurement unit is mounted in a clip member that secures the fingertip between its legs (either one pair or two pairs of legs). The provision of two pairs of legs advantageously enables to provide four-sided support for the finger, thereby preventing its folding at the distal phalanx.
There is thus provided according to the invention, a finger holder to be used in an optical measurement device for the non-invasive measurement of blood parameters, the finger holder comprising:
a clip member for securing the fingertip between its legs and supporting a measuring unit having an illumination-detection assembly for illuminating a first location of the finger, detecting light response of the illuminated location and generating data representative thereof;
a pressurizing assembly capable of applying desired over-systolic pressure to a second location on the patient's finger upstream of said first location with respect to a normal blood flow direction; and
a substantially rigid connector between the clip member and the pressurizing assembly, the connector being adapted to engage the finger along its middle phalanx and proximal intephalangeal joint, thereby preventing it from folding during measurements.
REFERENCES:
patent: 5002061 (1991-03-01), Close et al.
patent: 5025793 (1991-06-01), Chin
patent: 5218966 (1993-06-01), Yamasawa
patent: 5313940 (1994-05-01), Fuse et al.
patent: 5511546 (1996-04-01), Hon
patent: 5638816 (1997-06-01), Kiani-Azarbayjany et al.
patent: 5782757 (1998-07-01), Diab et al.
patent: 5810723 (1998-09-01), Aldrich
patent: 5860919 (1999-01-01), Kiani-Azarbayjany et al.
patent: 5924982 (1999-07-01), Chin
Finarov Alexander
Fine Ilya
Kleinman Yossie
Carter Ryan
Fitch Even Tabin & Flannery
O'Connor Cary
Orsense Ltd.
LandOfFree
Optical device for non-invasive measurement of blood related... does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Optical device for non-invasive measurement of blood related..., we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Optical device for non-invasive measurement of blood related... will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2524224