Method and device for monitoring relative blood volume of hemodialysis pipeline based on double optical paths

Abstract

The invention relates to the technical field of medical instruments, and provides a relative blood volume monitoring method and device for a hemodialysis pipeline based on double optical paths, the hemodialysis pipeline comprises a narrow-diameter section and a wide-diameter section which are connected, and the relative blood volume monitoring method comprises the following steps that S1, in dialysis treatment, red light and infrared light are adopted to irradiate the narrow-diameter section of the hemodialysis pipeline, and the narrow-diameter section of the hemodialysis pipeline is irradiated to obtain a blood volume monitoring result; the absorbance delta 1 red of the red light of the narrow-diameter section and the absorbance delta 1 infrared of the infrared light of the narrow-diameter section are calculated; s2, red light and infrared light are adopted to irradiate the wide-diameter section of the hemodialysis pipeline, and the absorbance delta 2 red of the red light of the wide-diameter section and the absorbance delta 2 infrared of the infrared light of the narrow-diameter section are calculated; s3, constructing an anti-oxyhemoglobin saturation change interference factor delta D red of the red light based on the delta 1 red and the delta 2 red; constructing an anti-oxyhemoglobin saturation change interference factor delta D infrared of the infrared light based on the delta 1 infrared and the delta 2 infrared; and S4, calculating the relative blood volume RBV based on the delta D red and the delta D infrared. The method has the advantage that accurate non-invasive monitoring of the relative blood volume is achieved.

Description

Technical Field

[0001] This invention relates to the field of hemodialysis monitoring technology, and more specifically, to a method and device for monitoring relative blood volume in a hemodialysis tubing based on a dual optical path. Background Technology

[0002] When a patient's kidneys fail and cannot effectively remove metabolic waste and excess water from the body, dialysis is necessary to sustain life. Hemodialysis uses a dialysis machine to draw blood out of the body, where it is exchanged through the dialyzer to remove metabolic waste and toxins. It also helps patients regulate electrolyte balance, stabilize their internal environment, and prevent risks such as serious arrhythmias.

[0003] In hemodialysis, relative blood volume (RBV) monitoring is crucial because it allows for real-time assessment of changes in blood concentration during dehydration. During treatment, the removal of water leads to blood concentration and a decrease in blood volume. If the rate of dehydration is too rapid or the total amount exceeds the patient's tolerance limit, it can easily trigger acute complications such as hypotension and muscle cramps. By dynamically monitoring RBV, healthcare professionals can visually observe the decline in blood volume, allowing for individualized adjustments to the amount and rate of dehydration to maintain it within a safe range.

[0004] Current relative blood volume measurements typically require drawing blood from the patient, an invasive procedure involving repeated punctures that cause pain, increase the risk of infection, and raise the probability of bloodborne disease transmission. Secondly, this method suffers from a time delay; blood samples need to be sent to a laboratory for analysis, failing to reflect the dynamic changes during dialysis in real time, resulting in delayed results. Furthermore, directly measuring relative blood volume in the blood within the extracorporeal dialysis tubing is susceptible to the influence of fluctuations in blood oxygen saturation, thus compromising the accuracy of the results. Summary of the Invention

[0005] The present invention aims to overcome at least one of the defects (deficiencies) of the prior art and provide a method and device for monitoring relative blood volume based on a dual-optical-path hemodialysis tubing, so as to achieve non-invasive and accurate detection of relative blood volume.

[0006] One objective of this invention is to provide a method for monitoring relative blood volume using a dual-optical-path hemodialysis tubing. The hemodialysis tubing includes a connected narrow-diameter section and a wide-diameter section, wherein the diameter of the wide-diameter section is larger than the diameter of the narrow-diameter section. The relative blood volume monitoring method includes the following steps: S1. During dialysis treatment, the narrow section of the hemodialysis tubing is irradiated with red light and infrared light respectively. Calculate the absorbance Δ1 of the red light in the narrow section. 红 Absorbance Δ1 of narrow-aperture infrared light 红外 ; S2. Irradiate the wide section of the hemodialysis tubing with red light and infrared light respectively, and calculate the absorbance Δ2 of the red light in the wide section. 红 Absorbance Δ2 of narrow-aperture infrared light 红外 ; S3, based on Δ1 红 and Δ2 红 Constructing a red light-based anti-interference factor ΔD for changes in blood oxygen saturation 红 Based on Δ1 红外 and Δ2 红外 Constructing an infrared light-based anti-interference factor ΔD for changes in blood oxygen saturation 红外 ; S4, based on ΔD 红 and ΔD 红外 Calculate relative blood volume (RBV).

[0007] Furthermore, step S1 specifically includes: The narrow section of the hemodialysis tubing was illuminated with red light and infrared light respectively, and the incident light intensity I of the red light and infrared light passing through the hemodialysis tubing was collected. 01红 and I 01红外 During dialysis treatment, the intensity I of the transmitted light from red and infrared light passing through the hemodialysis tubing at time t is collected. t1红 and I t1红外 Based on I 01红 and I t1红外 Calculate the absorbance Δ1 of red light in the narrow aperture segment. 红 Based on I 01红外 and I t1红外 Calculate the absorbance Δ1 of the narrow-aperture infrared light. 红外 .

[0008] Furthermore, step S2 specifically includes: The wide section of the hemodialysis tubing was illuminated with red light and infrared light respectively, and the incident light intensity I of the red light and infrared light passing through the hemodialysis tubing was collected. 02红 and I 02红外 During dialysis treatment, the intensity I of the transmitted light from red and infrared light passing through the hemodialysis tubing at time t is collected. t2红 and I t2红外 Based on I 02红 and I t2红外 Calculate the absorbance Δ2 of red light in the wide aperture band. 红 Based on I 02红外 and I t2红外 Calculate the absorbance Δ2 of the wide-aperture infrared light. 红外 .

[0009] Further, in step S3, the statement based on Δ1 红 and Δ2 红 Constructing a red light-based anti-interference factor ΔD for changes in blood oxygen saturation 红光Specifically, it is calculated based on the following formula: ; Where L1 is the pipe diameter of the narrow diameter section; L2 is the pipe diameter of the wide diameter section.

[0010] Further, in step S3, based on Δ1 红外 and Δ2 红外 Constructing an infrared light-based anti-interference factor ΔD for changes in blood oxygen saturation 红外 Specifically, it is calculated based on the following formula: ; Where L1 is the pipe diameter of the narrow diameter section; L2 is the pipe diameter of the wide diameter section.

[0011] Further, in step S4, the statement based on ΔD 红 and ΔD 红外 The relative blood volume (RBV) is calculated using the following formula: , Traditional methods of avoiding interference involve first detecting the interference and then compensating for it. However, the formula in this scheme directly eliminates interference information through the physical design of wide and narrow tube diameters combined with principles such as absorbance. The results calculated based on this are more reliable and accurate. Furthermore, by effectively eliminating the error factor of blood oxygen saturation, the sensitivity to detecting minute changes in blood volume throughout the measurement process is increased, which is beneficial for improving the stability of long-term monitoring.

[0012] The coefficients k and b are determined by in vitro blood calibration.

[0013] Furthermore, prior to step S1, the following steps are also included: S0. Before dialysis begins, pass a blood sample or saline solution through the hemodialysis tubing. Illuminate the hemodialysis tubing with red and / or green light and record the incident light intensity I. 入 The intensity of transmitted light (I) of red and / or green light passing through the hemodialysis tubing is collected. 透 Calculate the optical loss I using the following formula. 损 : I 损 =I 入 -I 透 .

[0014] Further, in step S4, the step based on ΔD 红光 and ΔD 红外 The relative blood volume (RBV) is calculated using the following formula: , Where e is a coefficient.

[0015] The coefficient e can be obtained by performing multiple irradiation experiments on the same section of the tube, comparing red light and green light irradiation with infrared light irradiation, and then calculating and fitting the coefficient e.

[0016] Another object of the present invention is to provide a relative blood volume monitoring device based on a dual-optical-path hemodialysis tubing, applicable to any of the relative blood volume monitoring methods described above. The relative blood volume testing device includes a hemodialysis tubing, which includes a connected wide-diameter section and a narrow-diameter section. A light source device is provided on one side of both the wide-diameter section and the narrow-diameter section, and the light source device is used to emit light to illuminate the hemodialysis tubing. A light detection device is provided on the other side of the wide-diameter section for detecting the transmitted light passing through the hemodialysis tubing.

[0017] Furthermore, the light source device is configured to switch between emitting green light, red light, and infrared light.

[0018] Compared with the prior art, the beneficial effects of the present invention are as follows: (1) This invention simulates this change by setting the wide and narrow diameter sections of the hemodialysis tubing, so that the light path of the light source passing through different sections of the hemodialysis tubing is different, thereby avoiding the interference of blood oxygen saturation on relative blood volume monitoring, realizing real-time and accurate monitoring of relative blood volume in vitro, improving the accuracy of monitoring results, and facilitating medical staff to obtain data on the relative blood volume of patients during dialysis in a timely manner.

[0019] (2) The present invention avoids the influence of light loss on the final monitoring results of relative blood volume, and further improves the accuracy of the monitoring results. Attached Figure Description

[0020] Figure 1 This is a structural diagram of the relative blood volume monitoring device of the present invention.

[0021] Reference numerals: hemodialysis tubing 100, wide diameter section 110, narrow diameter section 120, light source device 200, light detection device 300. Detailed Implementation

[0022] The accompanying drawings are for illustrative purposes only and should not be construed as limiting the invention. To better illustrate the following embodiments, some parts in the drawings may be omitted, enlarged, or reduced, and do not represent the actual product dimensions; it is understandable to those skilled in the art that some well-known structures and their descriptions may be omitted in the drawings.

[0023] Example 1 This embodiment provides a method for monitoring relative blood volume based on a dual-optical-path hemodialysis tubing, characterized in that... The hemodialysis tubing includes a connected narrow-diameter section and a wide-diameter section, wherein the diameter of the wide-diameter section is larger than the diameter of the narrow-diameter section. The relative blood volume monitoring method includes the following steps: S1. During dialysis treatment, the narrow section of the hemodialysis tubing is irradiated with red light and infrared light respectively. Calculate the absorbance Δ1 of the red light in the narrow section. 红 Absorbance Δ1 of narrow-aperture infrared light 红外 ; S2. Irradiate the wide section of the hemodialysis tubing with red light and infrared light respectively, and calculate the absorbance Δ2 of the red light in the wide section. 红 Absorbance Δ2 of narrow-aperture infrared light 红外 ; S3, based on Δ1 红 and Δ2 红 Constructing a red light-based anti-interference factor ΔD for changes in blood oxygen saturation 红 Based on Δ1 红外 and Δ2 红外 Constructing an infrared light-based anti-interference factor ΔD for changes in blood oxygen saturation 红外 ; S4, based on ΔD 红 and ΔD 红外 Calculate relative blood volume (RBV).

[0024] In this scheme, "wide" and "narrow" are relative terms; the diameter of the narrow section is smaller than that of the wide section. The hemodialysis tubing is connected to the dialysis tubing (or a dedicated tubing is used), through which blood flows. This scheme enables non-invasive monitoring of relative blood volume. Since blood oxygen saturation detection is based on changes in tubing diameter caused by the pulsation of blood vessels within the body, this scheme simulates this change by setting wide and narrow sections in the hemodialysis tubing. This results in different optical path lengths through which light passes through different sections of the hemodialysis tubing, thus avoiding interference from blood oxygen saturation on relative blood volume monitoring. This achieves real-time, accurate monitoring of relative blood volume outside the body, improving the accuracy of monitoring results and allowing medical staff to obtain timely data on the relative blood volume of patients during dialysis.

[0025] Furthermore, step S1 specifically includes: The narrow section of the hemodialysis tubing was illuminated with red light and infrared light respectively, and the incident light intensity I of the red light and infrared light passing through the hemodialysis tubing was collected. 01红 and I 01红外 During dialysis treatment, the intensity I of the transmitted light from red and infrared light passing through the hemodialysis tubing at time t is collected. t1红 and I t1红外 Based on I 01红 and I t1红外 Calculate the absorbance Δ1 of red light in the narrow aperture segment. 红 Based on I 01红外 and I t1红外 Calculate the absorbance Δ1 of the narrow-aperture infrared light. 红外 .

[0026] More specifically, Absorbance Δ1 of narrow-path red light 红 The calculation formula is: ; Absorbance Δ1 of narrow-aperture infrared light 红外 The calculation formula is: .

[0027] Furthermore, step S2 specifically includes: The wide section of the hemodialysis tubing was illuminated with red light and infrared light respectively, and the incident light intensity I of the red light and infrared light passing through the hemodialysis tubing was collected. 02红 and I 02红外 During dialysis treatment, the intensity I of the transmitted light from red and infrared light passing through the hemodialysis tubing at time t is collected. t2红 and I t2红外 Based on I 02红 and I t2红外 Calculate the absorbance Δ2 of red light in the wide aperture band. 红 Based on I 02红外 and I t2红外 Calculate the absorbance Δ2 of the wide-aperture infrared light. 红外 .

[0028] More specifically, the absorbance Δ2 of red light in the broad aperture band 红 The calculation formula is: ; Absorbance Δ2 of red light in the wide aperture band 红外 The calculation formula is: .

[0029] Further, in step S3, the statement based on Δ1 红 and Δ2 红 Constructing a red light-based anti-interference factor ΔD for changes in blood oxygen saturation 红 Specifically, it is calculated based on the following formula: ; Where L1 is the pipe diameter of the narrow diameter section; L2 is the pipe diameter of the wide diameter section.

[0030] Further, in step S3, based on Δ1 红外 and Δ2 红外 Constructing an infrared light-based anti-interference factor ΔD for changes in blood oxygen saturation 红外 Specifically, it is calculated based on the following formula: ; Where L1 is the pipe diameter of the narrow diameter section; L2 is the pipe diameter of the wide diameter section.

[0031] Further, in step S4, the statement based on ΔD 红光 and ΔD 红外 The relative blood volume (RBV) is calculated using the following formula: , The coefficients k and b are determined by in vitro blood calibration.

[0032] Furthermore, prior to step S1, the following steps are also included: S0. Before dialysis begins, pass a blood sample or saline solution through the hemodialysis tubing. Illuminate the hemodialysis tubing with red and / or green light and record the incident light intensity I. 入 The intensity of transmitted light (I) of red or green light passing through the hemodialysis tubing is collected. 透 Calculate the optical loss I using the following formula. 损 : I 损 =I 入 -I 透 .

[0033] Further, in step S4, the step based on ΔD 红光 and ΔD 红外 The relative blood volume (RBV) is calculated using the following formula: , Where e is a coefficient.

[0034] In this embodiment, infrared light passes through the hemodialysis tubing. A portion of the light is absorbed by the blood within the tubing, while another portion passes through the tubing to form transmitted light that is detected. Simultaneously, a small portion of the light is absorbed by the tubing itself and is also lost through reflection and scattering, which can affect the detection results to some extent. The green and red light used in this scheme are light sources that are essentially not absorbed (negligible) by the blood or saline solution within the tubing. The light loss is calculated by the difference between the incident and transmitted light of these two types of light and applied to the infrared light detection to avoid the impact of light loss on the final relative blood volume monitoring results, thereby further improving the accuracy of the monitoring results.

[0035] Example 2 like Figure 1As shown, this embodiment provides a relative blood volume monitoring device based on a dual-optical-path hemodialysis tubing 100, applicable to the relative blood volume monitoring method provided in Embodiment 1. The relative blood volume testing device includes a hemodialysis tubing 100, which includes a connected wide-diameter section 110 and a narrow-diameter section 120. A light source device 200 is provided on one side of both the wide-diameter section 110 and the narrow-diameter section 120, and the light source device 200 is used to emit light to illuminate the hemodialysis tubing 100. A light detection device 300 is provided on the other side of the wide-diameter section 110, and is used to detect the transmitted light passing through the hemodialysis tubing 100.

[0036] However, the above embodiments of the present invention are merely examples for clearly illustrating the technical solutions of the present invention, and are not intended to limit the specific implementation of the present invention. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the claims of the present invention should be included within the protection scope of the claims of the present invention.

Claims

1. A method for monitoring relative blood volume of a double light path-based hemodialysis line, characterized in that the hemodialysis line comprises a narrow-diameter section and a wide-diameter section connected in series, the wide-diameter section having a larger diameter than the narrow-diameter section, and the method comprises the following steps: Step S1: obtaining a first light signal of the narrow-diameter section; Step S2: obtaining a second light signal of the wide-diameter section; and Step S3: calculating a relative blood volume of the hemodialysis line according to the first light signal and the second light signal. The narrow-diameter section and the wide-diameter section are connected in series. The narrow-diameter section and the wide-diameter section are connected in series. S1, in the dialysis treatment, respectively adopting red light and infrared light to irradiate the narrow section of the hemodialysis pipeline, calculating the absorbance Δ1 of the narrow section red light 红 and the absorbance Δ1 of the narrow section infrared light 红外 ; S2, respectively, red light and infrared light irradiation blood purification pipe wide diameter section, the wide diameter section of red light absorbance Δ2 红 And narrow diameter section of infrared light absorbance Δ2 红外 ; S3, based on Δ1 红 and Δ2 红 Construct red light anti-blood oxygen saturation change interference factor ΔD 红 ; based on Δ1 红外 and Δ2 红外 Construct infrared light anti-blood oxygen saturation change interference factor ΔD 红外 ; S4, based on ΔD 红 and ΔD 红外 Calculate relative blood volume RBV.

2. The dual optical path based relative blood volume monitoring method for hemodialysis lines according to claim 1, characterized in that, The narrow-diameter section and the wide-diameter section are connected in series. The narrow diameter section of the hemodialysis pipeline is irradiated by red light and infrared light respectively, and the incident light intensity I of the red light and infrared light passing through the hemodialysis pipeline is collected 01红 and I 01红外 During the dialysis treatment, the transmission light intensity I of the red light and infrared light passing through the hemodialysis pipeline at t time is collected t1红 and I t1红外 Based on I 01红 and I t1红外 The absorbance Δ1 of the red light of the narrow diameter section is calculated 红 Based on I 01红外 and I t1红外 The absorbance Δ1 of the infrared light of the narrow diameter section is calculated 红外 .

3. The dual optical path based relative blood volume monitoring method for hemodialysis lines according to claim 1, wherein, Wherein, L1 is the diameter of the narrow-diameter section; and L2 is the diameter of the wide-diameter section. The wide diameter section of the hemodialysis pipeline is irradiated by red light and infrared light respectively, and the incident light intensity I of the red light and infrared light passing through the hemodialysis pipeline is collected 02红 and I 02红外 During the dialysis treatment, the transmission light intensity I of the red light and infrared light passing through the hemodialysis pipeline at t time is collected t2红 and I t2红外 Based on I 02红 and I t2红外 The absorbance Δ2 of the red light of the wide diameter section is calculated 红 Based on I 02红外 and I t2红外 The absorbance Δ2 of the infrared light of the wide diameter section is calculated 红外 .

4. The dual optical path based relative blood volume monitoring method for hemodialysis lines according to claim 1, wherein, In step S3, said based on Δ1 红 and Δ2 红 The anti-blood oxygen saturation change interference factor ΔD of red light is constructed 红光 , which is specifically calculated based on the following formula: ； Wherein, L1 is the diameter of the narrow-diameter section; and L2 is the diameter of the wide-diameter section.

5. The dual optical path based relative blood volume monitoring method for hemodialysis lines according to claim 1, wherein, In step S3, the anti-blood oxygen saturation change interference factor AD of the infrared light is constructed based on Δ1 红外 and Δ2 红外 红外 , and is specifically calculated based on the following formula:​ ； Wherein, the coefficients k and b are determined by in-vitro blood calibration.

6. The dual optical path based relative blood volume monitoring method for hemodialysis lines according to claim 1, wherein, In step S4, the relative blood volume RBV is calculated based on ΔD 红 and ΔD 红外 The relative blood volume RBV is calculated based on the following calculation formula: ， Before Step S1, the method further comprises the following step:

7. The dual optical path based relative blood volume monitoring method for hemodialysis lines according to any one of claims 1 to 6, characterized in that, Wherein, e is a coefficient. S0, before dialysis starts, pass a blood sample or normal saline through the hemodialysis line, irradiate the hemodialysis line with red light and / or green light, record the incident light intensity I of the red light and / or green light 入 , collect the transmitted light intensity I of the red light and / or green light passing through the hemodialysis line 透 ; calculate the light loss I 损 by the following formula: I 损 =I 入 -I 透 。 8. The dual optical path based relative blood volume monitoring method for hemodialysis lines according to claim 7, characterized in that, In step S4, the relative blood volume RBV is calculated based on the following calculation formula: 红光 and ΔD 红外 The relative blood volume RBV is calculated based on the following calculation formula: ， The relative blood volume testing device is suitable for the method of any one of claims 1-8, and comprises a hemodialysis line, the hemodialysis line comprising a wide-diameter section and a narrow-diameter section connected in series, a light source device being arranged on one side of the wide-diameter section and the narrow-diameter section, the light source device being configured to emit light to irradiate the hemodialysis line, and a light detection device being arranged on the other side of the wide-diameter section, the light detection device being configured to detect transmitted light passing through the hemodialysis line.

9. A dual optical path based relative blood volume monitoring device for hemodialysis tubing, comprising: The light source device is configured to emit green light, red light and infrared light in a switchable manner.

10. The relative blood volume monitoring apparatus according to claim 9, wherein ​

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