Patent application number | Description | Published |
20080242955 | RELIABILITY IN DETERMINATION OF CLINICAL STATE OF A SUBJECT - The invention relates to the determination of a diagnostic index indicative of the clinical state, especially nociceptive state, of a subject. In order to improve the quality of the determination process, desired input signals derived from the subject are monitored and the quality of the process is improved based on the monitoring. This is implemented by increasing user awareness of the reliability of the index or by controlling the measurement set-up. Quality information indicative of the reliability of the current index values may be produced based on the input signals. The quality information may then be employed to give an indication of the current reliability of the index and a warning if the reliability of the diagnostic index becomes compromised. | 10-02-2008 |
20090024011 | NON-INVASIVE DETERMINATION OF THE CONCENTRATION OF A BLOOD SUBSTANCE - In order to provide a non-invasive and continuous concentration measurement with the technology of standard pulse oximeters, an a priori relationship is created, through an in-vivo tissue model including a nominal estimate of a tissue parameter indicative of the concentration of a blood substance. The a priori relationship is indicative of the effect of tissue on in-vivo measurement signals at a plurality of wavelengths, the in-vivo measurement signals being indicative of absorption caused by pulsed arterial blood. In-vivo measurement signals are acquired from in-vivo tissue at the plurality of wavelengths and a specific value of the tissue parameter is determined based on the a priori relationship, the specific value being such that it yields the effect of the in-vivo tissue on the in-vivo measurement signals consistent for the plurality of wavelengths. The specific value then represents the concentration of the substance in the blood. | 01-22-2009 |
20090076354 | COMPENSATION OF HUMAN VARIABILITY IN PULSE OXIMETRY - The invention relates to a method of calibrating a pulse oximeter, in which the effects caused by tissue of a subject can be taken into account. A detector output signal is measured when living tissue of the subject is present between emitters and the detector in a sensor. Nominal calibration and nominal calibration characteristics are read from a memory, whereupon values for the same nominal characteristics for the sensor on living tissue of the subject are established using the detector output signal. Then, changes in the nominal calibration characteristics induced by the living tissue are calculated and a subject-specific calibration is formed by correcting the nominal calibration with the changes. Finally, the hemoglobin fractions are solved using the corrected nominal calibration. The invention also relates to a pulse oximeter having pre-stored data in a memory comprising data of initial characterization measurements, data of nominal characteristics describing calibration conditions under which a predetermined calibration of the apparatus has been applied, and data of nominal calibration and nominal calibration characteristics. An extinction coefficient compensation block is operatively connected to the first signal processing means and to the memory for reading data, said block comprising first calculation means adapted to correct the nominal characteristics of the sensor on living tissue of the subject. A transformation compensation block is operatively connected to the first signal processing means for receiving the DC signals and to the memory for reading data, said block comprising second calculation means adapted to correct the transformation values based on the changes in the DC signals induced by tissue of the subject. Alternatively, said data may be stored in the sensor part of the pulse oximeter. | 03-19-2009 |
20090326342 | METHOD, ARRANGEMENT AND SENSOR FOR NON-INVASIVELY MONITORING BLOOD VOLUME OF A SUBJECT - A method, arrangement and sensor for monitoring blood status of a subject are disclosed. In-vivo measurement signals indicative of absorption caused by blood are acquired at a plurality of measurement wavelengths. Based on the in-vivo measurement signals, successive values are determined for a hemoglobin parameter indicative of the concentration of hemoglobin in the blood of the subject and the blood volume status of the subject is monitored based on the successive values. The monitoring may involve determining the absolute value of the blood volume or relative changes in the blood volume. In one embodiment, the absolute value of the blood volume is indicated continuously together with hemoglobin concentration and composition. | 12-31-2009 |
20100081942 | METHOD, ARRANGEMENT AND APPARATUS FOR MONITORING FLUID BALANCE STATUS OF A SUBJECT - A method and apparatus for monitoring fluid balance status of a subject are disclosed. A hemoglobin measure indicative of hemoglobin concentration in the blood of a subject and at least one physiological parameter responsive to blood volume changes in the subject are determined and concurrent behavior of the hemoglobin measure and the at least one physiological parameter is indicated to a user, thereby to give an indication of fluid balance status of the subject. The cause and/or reliability of the fluid balance status may also be indicated. | 04-01-2010 |
20100280342 | MULTIPLE WAVELENGTH PHYSIOLOGICAL MEASURING APPARATUS, SENSOR AND INTERFACE UNIT FOR DETERMINATION OF BLOOD PARAMETERS - A measuring apparatus, a physiological sensor, and an interface unit for determining blood parameters of a subject are disclosed. The sensor comprises an emitter unit comprising a first plurality of emitter elements configured to emit radiation at a second plurality of wavelengths and a detector unit configured to receive radiation generated by the emitter elements and transmitted through the tissue of the subject, wherein the detector unit is further configured to produce electric measurement signals indicative of absorption caused by the blood of the subject. In order to make the sensor compatible with a variety of different monitoring units, the sensor or the interface unit is provided with a memory that stores emitter activation information for at least a third plurality of wavelengths, thereby to enable a monitoring unit operably connectable to the physiological sensor to employ a combination of wavelengths selected from the third plurality of wavelengths, wherein the third plurality is equal to or smaller than the second plurality. | 11-04-2010 |
20100280343 | MULTIPLE WAVELENGTH PHYSIOLOGICAL MEASURING APPARATUS, SENSOR AND INTERFACE UNIT FOR DETERMINATION OF BLOOD PARAMETERS - A measuring apparatus, a physiological sensor, and an interface unit for determining blood parameters of a subject are disclosed. The sensor comprises an emitter unit comprising a first plurality of emitter elements configured to emit radiation at a second plurality of wavelengths and a detector unit configured to receive radiation generated by the emitter unit and transmitted through tissue of the subject. The sensor further comprises a sensor memory storing sensor-specific information about the sensor unit, wherein the sensor-specific information includes at least calibration data for a given measurement mode, and a memory access interface for enabling an entity external to the sensor to update at least part of the sensor-specific information in a sensor ability update process, thereby to update ability of the sensor unit to operate in the given measurement mode. | 11-04-2010 |
20110077474 | METHOD, ARRANGEMENT AND APPARATUS FOR ASSESSING FLUID BALANCE STATUS OF A SUBJECT - A method, arrangement and apparatus for assessing fluid balance status of a subject are disclosed. At least one physiological parameter responsive to blood volume changes in the subject is determined and a predetermined change in the ventilation of the subject is produced. The response that the predetermined change of ventilation causes in at least one of the at least one physiological parameter is then determined, thereby to obtain at least one measure of change. The fluid balance status of the subject may be assessed based on the at least one measure of change. The subject is typically connected to a ventilator and the predetermined change is produced by controlling the ventilator. | 03-31-2011 |
20120209095 | SENSOR, APPARATUS AND METHOD FOR NON-INVASIVELY MONITORING BLOOD CHARACTERISTICS OF A SUBJECT - A sensor, apparatus and method for non-invasively monitoring blood characteristics of a subject are disclosed. The sensor comprises an emitter unit configured to emit radiation through the tissue of the subject at a plurality of measurement wavelengths and a detector unit that comprises photo detectors. To achieve a simple sensor assembly, the photo detectors are together adapted to receive the radiation at the plurality of wavelengths and to produce in-vivo measurement signals corresponding to the plurality of measurement wavelengths, the in-vivo measurement signals being indicative of absorption caused by blood of the subject. Furthermore, the photo detectors are mounted so that optical paths from the emitter unit to the photo detectors are different, and the plurality of wavelengths are divided between the photo detectors so that two spectrally adjacent photo detectors have at least one common wavelength. The apparatus comprises a path normalization unit configured to normalize the in-vivo measurement signals to an optical path specific to one of the photo detectors. | 08-16-2012 |
20120253147 | CALIBRATION METHOD AND ARRANGEMENT AND SENSOR FOR NON-INVASIVELY MEASURING BLOOD CHARACTERISTICS OF A SUBJECT - A calibration method for an apparatus for non-invasively monitoring blood characteristics of a subject is disclosed. The apparatus is provided with a computational model representing a relationship between in-vivo measurement signals obtained from the subject and the blood characteristics. The providing includes employing at least one tissue property variable in the computational model, in which the at least one tissue property variable is indicative of absorption and scattering characteristics of the subject's tissue. An arrangement for determining blood characteristics of a subject and a sensor for the arrangement are also disclosed. | 10-04-2012 |
20130165757 | METHOD, ARRANGEMENT, SENSOR, AND COMPUTER PROGRAM PRODUCT FOR NON-INVASIVELY MEASURING HEMOGLOBIN CONCENTRATIONS IN BLOOD - A mechanism for non-invasively monitoring blood characteristics of a subject is disclosed. To enable measurement of hemoglobin concentrations in a cost-effective way, a computational model is established that represents a relationship between a first variable indicative of total hemoglobin concentration and a set of variables that includes second variables indicative of light transmission through tissue and third variables indicative of concentration percentages of different hemoglobin species. In-vivo measurement signals are acquired from a subject and in-vivo values are determined for the second and third variables based on the in-vivo measurement signals. The first variable is then solved based on the in-vivo values of the second and third variables and the computational model. | 06-27-2013 |
20140005491 | METHOD FOR MONITORING SENSOR DEGRADATION, PATIENT MONITOR, PATIENT MONITOR SYSTEM, PHYSIOLOGICAL SENSOR, AND COMPUTER PROGRAM PRODUCT FOR A PATIENT MONITOR | 01-02-2014 |