Method and device for measuring blood oxygen saturation

Abstract

The invention discloses an oxygen saturation measuring method and a device. The method comprises procedures that: the transmission intensities of a first wavelength light and a second wavelength light transmitting the organization of living organisms are collected respectively and converted into a first corresponding wavelength light signal and a second corresponding wavelength light signal; at least one interval is defined on the waveform of the first and the second wavelength light signals; the area integral of the waveform of the first and the second wavelength light signals in one interval at least is processed to obtain the total area integrals of the first and the second wavelength light signals; the ratio of the total area integrals of the first and the second wavelength light signals is referred as oxygen content R; and the oxygen saturation is calculated according to a following formula: SpO<2>=(AxR+B) / (CxR+D). The method and the device can measure a current oxygen value correctly by analyzing and calculating the waveform of a pulse under the condition of weak perfusion.

Description

【Technical field】 [0001] The invention relates to a method and device for measuring blood oxygen saturation, in particular to a method and device for measuring blood oxygen saturation under weak perfusion conditions by using spectrophotometry. 【Background technique】 [0002] At present, pulse oximeters are generally used for blood oxygen saturation measurement at home and abroad. The basic structure of the measuring device includes a blood oxygen probe and a signal processing device. The blood oxygen probe is a sensor composed of a light-emitting diode and a photosensitive element. Light emitting diodes provide light of two or more wavelengths. The function of the photosensitive element is to convert the optical signal with blood oxygen saturation information passing through the end of the tissue into an electrical signal, and digitize the signal after passing through the signal processing circuit. For this digital quantity, the blood oxygen saturation calculated by a certa...

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Problems solved by technology

However, this method has great defects. When the patient is under the condition of weak perfusion, the signal-to-noise ratio is very low because the signal is very weak. At this time, the peak and trough are seriously distorted due to superimposed noise. image 3 It is a traced waveform under the condition of weak perfusion, because the pulse rate of the human body is generally less than 300 times per minute (corresponding frequency is 5Hz), so the signal is passed through a finite impulse response filter with a cutoff frequency of 6Hz, which can filter out the signal bandwidth Most of the noise, the filtered signal such as Figure 4 As shown, due to the existence of interference, it is difficult to accurately judge the peak and valley values ​​of the two paths of light, so there will be errors in the search for pulse wave peaks and valleys. The peaks and valleys of the two signals in the figure are respectively M I , M R , V I and V R , due to the distortion of the peak and trough, the obtained AC-DC ratio may also be wrong, and it is difficult to guarantee the correctness of the blood oxygen saturation measurement result at this time

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