A probe apparatus for use with an optical oximeter is disclosed. A pair of light emitting diodes emit light of known narrow wavelengths through an appendage of a patient onto a photosensor. A resistor of coded known resistance is used to enable the oximeter to calculate the co-efficient of extinction of the wavelengths of the LEDs. The resistor, LEDs and photosensor are mounted on self-attaching hook and eye tape for mounting the probe onto the appendage of the patient. The probe is detachably wired to the oximeter, rendering the probe completely disposable. The oximeter is programmed at the factory to calculate the co-efficients of extinction of any LEDs which may be encountered in a series of disposable probes. From the co-efficients of extinction, the pulse rate and degree of arterial oxygen saturation is computed and displayed by the oximeter.

Calibrated optical oximeter probe

An instrument (100) and a method for determining a coagulation characteristic of blood, a blood fraction or a control comprise a radiation-reflective surface (194), a first source (244) for irradiating the surface (194), and a first detector (242) for detecting radiation reflected from the surface (194). A cuvette (101) holds a sample (514) of the blood, blood fraction or control the coagulation characteristic of which is to be determined. The cuvette (101) has two opposed walls (506, 508) substantially transparent to the source (244) radiation and reflected radiation. The first source (244) and first detector (242) are disposed adjacent a first one (508) of the two opposed walls (506, 508) and the radiation reflective surface (194) is disposed adjacent a second (506) or the two opposed walls (506, 508).

Fluid dose, flow and coagulation sensor for medical instrument

This invention is an improve non-invasive electro-optical sensor probe (10) that is initially L shaped to provide a mechanical means for accurate positioning of the sensor for subsequent use in connection with a patient appendage. The sensor further includes a leveling pad for at least partially surrounding a protruding sensor element (22, 24) to minimize protrusion of the element into the skin of a patient, and a functional liner (18) for use in pretest of the sensor prior to positioning on a patient.

Oximeter sensor with functional liner

The present invention provides a compact, highly automated photometric analyzer for measuring the concentration of substances found in a fluid, typically a blood sample or other body fluid sample taken from a patient. The operator places a small quantity of the sample into a special rotor and then loads the rotor into the analyzer. The analyzer accepts the rotor, centrifuges and dilutes the sample, and distributes the sample into a plurality of cuvettes near the outer edge of the rotor. Some of these cuvettes hold reagents which react with the sample. The analyzer then measures light absorption within the sample at a number of preselected frequencies. According to the present invention, a pair of specially designed apertures direct light from the sample through a plurality of beam splitters, interference filters, and associated photodetectors. The system also includes means for performing automatic calibration and error checking functions. These means include a through hole through the rotor, and an opaque body carried by the rotor. Additionally, measurements may be repeated through a given cuvette and the results averaged to minimize the effect of random variations between measurements.

Methods for photometric analysis

A method for calculating a coagulation characteristic of a sample of blood, a blood fraction, or a control comprises generating an output signal indicative of coagulation of the sample, sampling the output signal at a sampling rate for a predetermined time to provide a plurality of sampled signal values, storing the sampled signal values, rectifying the stored sampled signal values to provide a plurality of envelope values, and storing the envelope values. The stored envelope values are examined in reverse time order to determine a slope of the envelope at each of the stored envelope values. All relative maxima in the stored envelope values are identified. A range of stored envelope values corresponding to each relative maximum is determined. The identified relative maxima are compared to locate an absolute maximum in the stored envelope values. The coagulation characteristic is then calculated from the stored envelope values within the predetermined range of envelope values corresponding to the absolute maximum.

Method and apparatus for calculating a coagulation characteristic of a sample of blood a blood fraction or a control

A combined blood constituent and prothrombin time analyzer is provided in which a plurality of removable and replaceable circuit modules are utilized to program the analyzer for appropriate light wavelength, reagent blank offset, scale factors and calibration parameters and which is self referencing to predetermined standards such that the results derived are all normalized for readout on a common digital readout device. The entire analyzer is contained in a compact console which includes controlled incubated storage for blood test samples together with insertion cavities for both constituent concentration and prothrombin time analysis. The results of each analysis are so normalized by the blood analyzer that a common digital counter can be used to convert these results to a numerical readout presentable on a common readout device and said results are substantially instantaneously displayed subsequent to initiation of any given test in the analyzer.

Raymond W. Kiess

Papers

Digital direct reading colorimeter