JPH10216113A - Heart failure monitoring apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To output an early warning about the occurrence of heart failure. SOLUTION: A heart failure warning signal of a living being is outputted by a heart failure warning means 76 based on a changing range WSAO2 of the degree of oxygen saturation SaO2 in blood, as calculated by a means 70 for calculating a changing range of the degree of oxygen saturation, which exceeds a preset judgment reference value W1 . The changing range of the degree of oxygen saturation SaO2 increases before the degree of oxygen saturation SaO2 apparently lowers with the progress of the heart failure. This nature allows this means to output an early warning about the occurrence of a heart failure thereby enabling early start of medical action for a patient attacked by the heart failure.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a heart failure monitor for monitoring heart failure in a living body.

[0002]

2. Description of the Related Art Heart failure, in which the necessary quantity and quantity of blood cannot be circulated to organ tissues throughout the body due to a decrease in the contractile force of the heart due to various etiologies, etc., appears as an end-stage symptom of heart disease. However, the condition often worsens at night compared to daytime. In hospitals and homes, it is difficult to secure the number of nurses during such nights, and nursing care for patients becomes inadequate. Therefore, an apparatus capable of accurately monitoring the occurrence of heart failure as described above is desired.

On the other hand, by utilizing the fact that the above-mentioned heart failure appears in the decrease in oxygen saturation of arterial blood as in the case of decrease in respiratory function, a non-invasive arterial blood oxygen saturation measurement apparatus has conventionally been used. If the blood oxygen saturation SpO2 (%) of the patient measured by the arterial blood oxygen saturation measuring device falls below a preset value, for example, 90%, a sound, light or electric signal alarm is output. It was like.

[0004]

According to the monitoring using the conventional arterial blood oxygen saturation measuring device, an alarm is output when the oxygen saturation of the arterial blood actually decreases. There is a disadvantage that the medical treatment tends to be delayed because the time allowed for the medical treatment is not sufficiently obtained.

The present invention has been made in view of the above circumstances, and it is an object of the present invention to provide a heart failure monitoring device capable of outputting an early warning of the occurrence of heart failure.

The present inventors have made various studies on the background of the above circumstances, and as a result, as the degree of heart failure progresses, the oxygen saturation SpO2 measured by the arterial blood oxygen saturation measuring device becomes higher. Found that the fluctuation range became large before it clearly declined. The present invention has been made based on such findings.

[0007]

The gist of the present invention is to provide a heart failure monitoring device for monitoring heart failure in a living body, wherein (a) the blood oxygen saturation of the living body is
Blood oxygen saturation measuring means for non-invasively and continuously measuring blood oxygen saturation; and (b) an oxygen saturation fluctuation width for calculating a fluctuation width of blood oxygen saturation measured by the blood oxygen saturation measuring means. Calculating means, and (c) outputting the heart failure warning signal of the living body based on the fact that the fluctuation range of the blood oxygen saturation calculated by the oxygen saturation fluctuation width calculating means exceeds a predetermined judgment reference value. And heart failure alarm means.

[0008]

According to this configuration, the heart failure warning means determines that the fluctuation range of the blood oxygen saturation calculated by the oxygen saturation fluctuation range calculating means exceeds a predetermined reference value. A heart failure alarm signal for the living body is output. According to the present invention, the alarm indicating the occurrence of heart failure is early according to the present invention, since the fluctuation range of the oxygen saturation SpO2 has a property of increasing before the oxygen saturation SpO2 clearly decreases with progression of heart failure. Is output to Therefore, medical treatment for a patient with heart failure can be started early.

[0009]

In another embodiment of the present invention, preferably, (d) the pulse rate calculating means for sequentially calculating the pulse rate PR (1 / min) of the living body, and (e) the pulse rate calculating means for calculating the pulse rate. Pulse rate fluctuation range calculating means for calculating the fluctuation range of the pulse rate, wherein the heart failure warning means is configured such that the pulse rate fluctuation width calculated by the pulse rate fluctuation width calculating means exceeds a predetermined reference value. And outputting the heart failure alarm signal of the living body based on the fact that the fluctuation range of the blood oxygen saturation calculated by the oxygen saturation fluctuation width calculation means exceeds a predetermined judgment reference value. . Since the fluctuation range of the pulse rate PR increases with the progression of heart failure, the present invention can further enhance the reliability of an alarm indicating the occurrence of heart failure.

[0010]

Preferred embodiments of the present invention will be described below in detail with reference to the accompanying drawings.

FIG. 1 shows a reflection type pulse oximeter functioning as a heart failure monitoring device, that is, a blood oxygen saturation measuring device 28 for measuring oxygen saturation SpO2 in arterial blood.
Is shown. In FIG. 1, a reflection type probe 1
0 is, for example, a forehead with a relatively high density of peripheral blood vessels of a living body,
It is worn in close contact with the body surface 12 such as a finger. The reflective probe 10 has a cylindrical housing 14 having a relatively shallow bottom and a central portion of the bottom inner surface of the housing 14 for detecting backscattered light that is scattered in the body surface 12 and emitted to the light source side. A light receiving element 16 which is provided in the
4 having the same radius r centered on the light receiving element 16 on the bottom inner surface.
Are provided alternately at predetermined intervals on the circumference of
A plurality (eight in this embodiment) of the first light emitting element 18 and the second light emitting element 20 and the light receiving element 16 and the light emitting elements 18 and 2 are integrally provided in the housing 14.
, A light-receiving element 16 and light-emitting elements 18, 20 in the housing 14.
And an annular light-shielding wall 24 that shields reflected light from the inside of the body surface 12 of the light emitted from the light-emitting elements 18 and 20 toward the light-receiving element 16.

The first light emitting element 18 has a first wavelength λ.₁And
For example, it emits red light having a wavelength of about 730 nm, and emits second light.
The element 20 has the second wavelength λ_TwoFor example, a wavelength of about 880 nm
Which emits infrared light. In FIG. 2, one-dot chain
Line is the extinction coefficient of oxygenated hemoglobin (oxy-hemoglobin)
And the solid line shows deoxy-hemoglob.
In) shows the extinction coefficient. The first wavelength λ₁Is an acid
Extinction coefficient between oxyhemoglobin and anoxic hemoglobin
The region where the difference is larger than a predetermined value, that is,
The value within the short wavelength range and set as high as possible
The second wavelength λ_TwoIs oxygenated hemoglobin
Absorption coefficient difference from anoxic hemoglobin is smaller than the specified value
Area, that is, the area on the wavelength side longer than 800 nm
Value and set as low as possible. In addition, above
The first wavelength λ₁And the second wavelength λ _TwoAre not necessarily
Is not limited to the wavelength of oxygenated hemoglobin
Extinction coefficient of oxygen-depleted hemoglobin is large
Wavelengths that have different wavelengths and wavelengths that have approximately the same extinction coefficient
Any length is acceptable.

The first light emitting element 18 functioning as a light source
The second light emitting element 20 and the second light emitting element 20 are alternately driven by the drive circuit 54, so that the first light emitting element 18 and the second light emitting element 20 travel toward the living tissue (the vascular bed) immediately below the body surface 12 at the first wavelength λ. _When the light of the first wavelength and the light of the second wavelength λ ₂ are alternately emitted, the backscattered light scattered by blood cells and the like contained in the blood in the blood capillaries of the living tissue emerges from the body surface 12. the light receiving element 16 square scattered light i.e. the reflected light from the living tissue (vascular beds) serves as a common light sensor is respectively received, the first optical signal of a first wavelength lambda ₁ of the scattered light SV _R and the second The second optical signal SV _IR indicating the scattered light having the wavelength λ ₂ is output.

FIG. 3 is a view of the housing 14 of the reflective probe 10 as viewed from the surface facing the body surface 12. A light receiving element 16 is disposed at the center of the housing 14, the annular light shielding wall 24 is fixed at a concentric position, and a plurality of first light emitting elements 18 and second light emitting elements 20 Outside the light-shielding wall 24,
They are alternately arranged along a concentric circle having a radius r shown by a dashed line. The radius r is detected by the first optical signal SV AC-DC component ratio _R (AC / DC) AC-DC component ratio _R and the second optical signal SV _IR (AC / DC) _IR is sufficiently large and the optical element 16 The intensity of the backscattered light is set within a range of 5 to 7 mm, which is a range in which the measurement is not unstable.

First light emitting element 18 and second light emitting element 20
Are alternately emitted at a relatively high frequency of about several hundred Hz to several kHz for a certain period of time.
Is the first optical signal SV _R indicating the backscattered light of the first wavelength λ ₁
An optical signal SV including the second optical signal SV _IR indicating the backscattered light having the second wavelength λ ₂ is output to the low-pass filter 32 via the amplifier 30. The low-pass filter 32 removes noise having a frequency higher than the frequency of the pulse wave from the input optical signal SV, and outputs the optical signal SV from which the noise has been removed to the demultiplexer 34. The above first optical signal S
V _R and the second optical signal SV _IR change in synchronization with the pulse.

The demultiplexer 34 of the blood oxygen saturation measuring device 28 controls the first light emitting element 1 according to a switching signal SC described later.
By switched 8 and in synchronism with the emission of the second light emitting element 20, the first optical signal SV _R is the first wavelength lambda ₁ of the red light through a sample-and-hold circuit 36 and A / D converter 38 calculation I / O port 40 in control circuit 39
And a second optical signal SV _IR which is infrared light of the second wavelength λ ₂ ,
It is sequentially supplied to the I / O port 40 via the / D converter 44. When sequentially outputting the input optical signals SV _R , SV _IR to the A / D converters 38, 44, the sample-hold circuits 36, 42 perform A / D conversion on the previously output optical signals SV _R , SV _IR. The optical signals SV _R and SV _IR to be output next are held until the conversion operation in the devices 38 and 44 is completed.

The I / O port 40 is connected to a CPU 46, a ROM 48, a RAM 50, and a display 52 via data bus lines. The CPU 46 sets the RA
Using the storage function of M50, the measuring operation is executed in accordance with a program stored in the ROM 48 in advance, and a command signal SLD is output from the I / O port 40 to the drive circuit 54 to output the first light emitting element 18 and the second light emitting element 20. Alternately emit light at a relatively high frequency of about several hundred Hz to several kHz for a certain period of time, and output a switching signal SC in synchronization with the light emission of the first light emitting element 18 and the second light emitting element 20 to perform demultiplexing. 34, the first optical signal SVR is _sent to the sample-and-hold circuit 36 and the second optical signal SVR is
V _IR is distributed to the sample and hold circuit 42. Further, the CPU 46 sequentially determines the oxygen saturation SpO2 in the blood flowing through the peripheral blood vessels based on the photoplethysmographic waveforms represented by the first optical signal SV _R and the second optical signal SV _IR according to a program stored in advance, and The indicator 52 displays the determined oxygen saturation SpO2.

Here, in the present embodiment, a cap-shaped rubber member 56 is provided integrally with the housing 14 so as to cover the outer peripheral surface and the bottom outer surface of the housing 14. The rubber member 56 is formed in a sponge shape using, for example, chloroprene rubber or the like as a raw rubber, and has a suitable heat insulating property. Then, a portion of the rubber member 56 located on the outer peripheral side of the housing 14 is fixed to the body surface 12 via the double-sided adhesive sheet 58, so that the opening end surface of the housing 14 and the light shielding member 24
The probe 10 is mounted on the body surface 12 such that the distal end surface of the probe 10 is in close contact with the body surface 12. In FIG. 1, the double-sided pressure-sensitive adhesive sheet 58 is drawn much thicker than it is for convenience.

FIG. 4 is a functional block diagram for explaining a main part of the control function of the arithmetic control circuit 39. 4, the blood oxygen saturation measuring means 68, firstly, by a frequency analysis operation using the fast Fourier transform, AC components AC _R and DC components of the first optical signal SV _R every predetermined interval
_R and alternating current component AC _IR and DC component DC _IR of the second optical signal SV _IR are sequentially determined respectively, then, the first optical signal SV AC component of the _R AC _R and the direct current component DC _R and the second optical signal SV the AC component of the _IR AC _IR and DC component DC _IR
And a, AC-DC component ratio of the first optical signal SV _R (AC _R /
DC _R ) and the AC / DC component ratio of the second optical signal SV _IR (AC _IR /
DC _IR ) is calculated respectively, and for example, FIG.
From the relationship shown in equation (1) set in advance as shown by the solid line,
AC-DC component ratio of the first optical signal _{SV R (AC R / DC R} )
And the ratio R [= (AC _R / DC _R ) / (AC _IR / DC _IR )] of the second optical signal SV _{IR to} the AC-DC component ratio (AC _IR / DC _IR )
Is used to calculate the oxygen saturation SpO2 of the living body. In Equation (1), A is a negative constant indicating a slope, and B is a constant indicating an intercept.

[0020]

## EQU1 ## SpO2 = A × R + B (1)

The oxygen saturation fluctuation width calculating means 70 calculates the fluctuation width W _SP02 of the oxygen saturation SpO2 continuously obtained by the blood oxygen saturation measuring means 68 within a predetermined section T ₀ .
Is calculated. This fluctuation width W _SP02 is determined by the predetermined section T _0.
May be determined from the standard deviation σ in the distribution of the values of the oxygen saturation SpO2 at the inner it may be determined from the difference between the maximum value and the minimum value of the oxygen saturation SpO2 within the predetermined period T _0. The predetermined section T ₀ is set experimentally in order to detect a change in the oxygen saturation SpO2 indicating a precursor state of heart failure, and for example, a value in a range from several minutes to tens of minutes is used.

The pulse rate calculating means 72 includes, for example, a first optical signal
No. SV_RAnd the second optical signal SV_IRPulsates in sync with the pulse
Of the signal of one of them
Based on the pulsation cycle, the pulse rate PR (1 / min) of the living body is set to 1
Calculated sequentially for each beat. The pulse rate fluctuation range calculating means 74
The predetermined section T₀Within the pulse rate calculating means 72
The fluctuation width W of the pulse rate PR of the living body calculated sequentially_PRIs calculated
Put out. This fluctuation width W _PRIs also determined by the predetermined section T₀Within
From the standard deviation σ in the distribution of the pulse rate PR
Or the predetermined section T₀Pulse rate within
It may be obtained from the difference between the highest value and the lowest value of PR.

The heart failure alarm means 76 determines whether the pulse rate fluctuation width W _PR calculated by the pulse rate fluctuation width calculating means 74 exceeds a predetermined reference value W ₂ and the oxygen saturation fluctuation width calculating means 70. Oxygen saturation S calculated by
criterion value variation width W _SP02 preset the pO2 W ₁
And outputs a heart failure alarm signal for notifying the occurrence of heart failure in the living body based on the fact that the value exceeds. The criterion values W ₁ and W ₂ are values characteristically indicating a state before the occurrence of heart failure, are experimentally determined, and may be constant values. However, the blood oxygen saturation SpO2
Since the width of variation of a feature value in the nighttime becomes larger than during the day, by the predetermined margin value α to the stored fluctuation range during the day is added, the determination reference value W ₁ is determined You may.

FIG. 6 shows that the degree of cardiac dysfunction is classified into four stages of (I), (II), (III), and (IV) in order of lightness, and the blood in the living body belonging to each of these four stages is measured. The graph shows changes over time in the oxygen saturation SpO2 and the pulse rate PR. As is clear from FIG.
The greater the degree of cardiac dysfunction, the greater the blood oxygen saturation Sp
Fluctuation width W _PR of the variation width W _SP02 and pulse rate PR of O2 tends to be large. The heart failure warning means 76 uses such a tendency to output a heart failure warning signal for announcing the occurrence of cardiac dysfunction before the blood oxygen saturation SpO2 clearly decreases.

FIG. 7 shows the control operation of the arithmetic and control circuit 39.
FIG. 4 is a flowchart for explaining main parts of FIG. FIG.
In step SA1, the first wave
Long λ ₁Optical signal SV representing the backscattered light of_RAnd the second
Wavelength λ_TwoOptical signal SV representing the backscattered light of_IRIs read
I will. Next, in SA2, the first optical signal SV_ROr
Second optical signal SV_IROf the biological pulse rate PR from the pulsation cycle
Will be issued. Then, the blood oxygen saturation measuring means 68
In the corresponding SA3 to SA5, the oxygen saturation of the living body
SpO2 is calculated.

That is, in SA3, the first optical signal SV _R and the second optical signal SV _IR read in SA1 are subjected to frequency analysis processing, so that the first optical signal SV _R
R AC component AC _R (signal power value) and DC component DC
_R (signal power value) and the AC component AC of the second optical signal SV _IR
IR (signal power value) and DC component DC _IR (signal power value)
Are extracted respectively. Next, in SA4, the above S
First optical signal SV _R ac component A extracted in A3
From the C _R and the DC component DC _R , the first optical signal SV _R
With AC to DC component ratio AC _R / DC _R is calculated for, S
AC component A of the second optical signal SV _IR extracted in A3
From the C _IR and the DC component DC _IR , the second optical signal SV _IR
AC-DC component ratio AC _IR / DC _IR of is calculated. And S
In A5, for example, from a preset relationship indicated by the solid line in FIG. 5 (SpO2 = A × R + B), AC-DC component ratio of AC to DC component ratio AC _R / DC _R and the second optical signal SV _IR of the first optical signal SV _R The ratio R to AC _IR / DC _IR [= (AC _R / DC _R ) /
( _ACIR / _DCIR )] based on the oxygen saturation S of the living body.
pO2 is calculated.

At SA6, the calculation at SA5 is performed.
The displayed oxygen saturation SpO2 of the living body is displayed on the display 52.
And at SA7, the timer counter CT
After “1” is added to the value, at SA8, the timer
The judgment reference time T in which the contents of the counter CT are set in advance₀Less than
It is determined whether or not it is up. This judgment reference time T ₀
Is the variation of oxygen saturation SpO2, which indicates a precursor state of heart failure
Is set experimentally in order to detect.

Initially, the determination at SA8 is denied, so that the pulse rate PR and the oxygen saturation SpO2 are sequentially calculated by repeatedly executing SA1 and subsequent steps. However, while the pulse rate PR and the oxygen saturation SpO2 are sequentially calculated, when the content of the timer counter CT reaches the determination reference time T ₀ , the determination of SA8 is affirmative, so that the oxygen saturation variation width calculation means 70 and SA9 corresponding to the pulse rate fluctuation calculating means 74, the oxygen saturation fluctuation width W _SP02 and the fluctuation width W _PR of the pulse rate PR within the fixed section T ₀ are changed to the oxygen saturation fluctuation width within the above section T ₀ . It is calculated based on, for example, _obtaining the standard deviation σ of W _SP02 and the pulse rate PR.

Next, SA10 and A11 corresponding to the heart failure alarm means 76 are executed. In SA10,
The SA9 exceed the calculated criterion value W ₂ to pulse rate variation width W _PR is preset by, and criteria variation width W _SP02 blood oxygen saturation SpO2 calculated is set in advance by the SA9 whether exceeds the value W ₁ is determined. If the determination of SA10 is denied, SA12 is executed without execution of SA11. If the determination is affirmed, in SA11, a heart failure warning signal for notifying the occurrence of heart failure in the living body is optically or Output by voice. Then, after the content of the timer counter CT is cleared to "0" in SA12, the present routine is terminated, and SA1 and subsequent steps are executed again.

As described above, according to the present embodiment, the fluctuation range of the blood oxygen saturation SpO2 calculated by the heart failure warning means 76 (SA10, SA11) and the oxygen saturation fluctuation width calculation means 70 (SA9) is obtained. Based on the fact that W _SP02 exceeds a predetermined judgment reference value W ₁ , a heart failure alarm signal of the living body is output. According to the present embodiment, the alarm indicating the occurrence of heart failure is generated according to the present embodiment because the fluctuation range of the oxygen saturation SpO2 has a property of increasing before the oxygen saturation SpO2 clearly decreases with progression of heart failure. Output early. Therefore, medical treatment for a patient with heart failure can be started early.

In the present embodiment, the pulse rate PR of the living body is
Pulse rate calculating means 72 (SA) for sequentially calculating (1 / min)
2) and a pulse rate fluctuation width calculating means 7 for calculating a fluctuation width W _PR of the pulse rate _PR calculated by the pulse rate calculating means 72
4 (SA9) and the heart failure alarm means 76 (SA
10, SA11) is obtained when the pulse rate variation width W _PR calculated by the pulse rate variation width calculation means 74 exceeds a predetermined reference value W ₂ and the oxygen saturation variation width calculation means 70 calculates the pulse rate variation width W _PR. variation width W _SP02 blood oxygen saturation SpO2 was based on the fact that exceeds the determination reference value W ₁ which is set in advance, and outputs a failure alarm signal of the living body. Since the fluctuation width W PR of the pulse rate _PR has a property of increasing with progress of heart failure, according to the present invention, the reliability of an alarm indicating the occurrence of heart failure can be further enhanced.

Although the embodiment of the present invention has been described with reference to the drawings, the present invention can be applied to other embodiments.

For example, the heart failure warning means 76 of the above-described embodiment determines that the pulse rate fluctuation width W _PR exceeds a predetermined judgment reference value W ₂ and the blood oxygen saturation SpO 2 fluctuation width W _SP02.
Although but was to output heart failure warning signal of the living body based on exceeding the criterion value W ₁ which is set in advance, the variation width W _SP02 blood oxygen saturation SpO2 is preset determination reference value no problem even outputs a failure alarm signal of the living body based on exceeding the W _1.

In the above embodiment, the light-receiving element 16, the light-emitting elements 18, 20 are provided on the same side with respect to the body surface 12, so that the light-receiving element 16 detects the backscattered light. Although a light-receiving element and a light-emitting element are provided to face each other via, for example, an earlobe or the tip of a finger, the light-receiving element may use a so-called transmission probe that detects forward scattered light. Absent.

Further, the heart failure monitoring apparatus, that is, the blood oxygen saturation measuring apparatus 28 of the above-described embodiment has both the oxygen saturation measuring function and the heart failure alarm judgment output function, but is provided independently. It may output a heart failure alarm based on a measurement signal from the blood oxygen saturation measuring device.

The blood oxygen saturation measuring means 68 of the above-described embodiment calculates the actual blood oxygen saturation SpO2 from a preset relationship shown by the solid line in FIG. A non-linear relationship indicated by a broken line 5 may be used.

The blood oxygen saturation measuring means 68 of the above-mentioned embodiment is for outputting an alarm for heart failure optically or voicely, but outputs an electric signal indicating the alarm for heart failure. It can be anything.

Further, the reflection type probe 10 of the above-described embodiment is used.
In the above, various changes can be made to the number and arrangement position of the light emitting elements 18 and 20.

In addition, the present invention can be variously modified without departing from the spirit thereof.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a configuration of a heart failure monitoring device according to one embodiment of the present invention.

FIG. 2 shows a first wavelength λ _R used in the embodiment of FIG.
FIG. 5 is a diagram showing the relationship between the second wavelength λ _IR and the extinction coefficients of oxygenated hemoglobin and oxygen-free hemoglobin.

FIG. 3 is a diagram showing a surface facing a body surface of a reflection type probe used in the embodiment of FIG. 1;

FIG. 4 is a functional block diagram illustrating a main part of a control function of the arithmetic control circuit in FIG. 1;

FIG. 5 is a diagram showing a preset relationship used in the blood oxygen saturation measuring means of FIG. 4;

FIG. 6 shows the degree of cardiac dysfunction in the order of lightness (I),
When classified into four stages (II), (III) and (IV),
It is a figure which shows the time-dependent change of blood oxygen saturation SpO2 and the pulse rate PR about the living body which respectively belongs to those four steps.

FIG. 7 is a flowchart illustrating a main part of a control operation of the arithmetic control circuit in FIG. 1;

[Explanation of symbols]

 28: Blood Oxygen Saturation Measuring Device (Heart Failure Monitoring Device) 68: Blood Oxygen Saturation Measuring Means 70: Oxygen Saturation Fluctuation Width Calculation Means 72: Pulse Rate Calculation Means 74: Pulse Rate Fluctuation Width Calculation Means 76: Heart Failure Alarm means

Claims (2)

[Claims] 1. A heart failure monitoring device for monitoring heart failure of a living body, comprising: a blood oxygen saturation measuring means for non-invasively and continuously measuring the blood oxygen saturation of the living body; Oxygen saturation fluctuation width calculating means for calculating the fluctuation width of the blood oxygen saturation measured by the blood oxygen saturation measuring means, and fluctuation of the blood oxygen saturation calculated by the oxygen saturation fluctuation width calculating means A heart failure warning device that outputs a heart failure warning signal for the living body based on the fact that the width exceeds a predetermined judgment reference value. 2. A heart rate alarm, comprising: a pulse rate calculating means for sequentially calculating the pulse rate of the living body; and a pulse rate fluctuation range calculating means for calculating a fluctuation range of the pulse rate calculated by the pulse rate calculating means. The pulse rate fluctuation range calculated by the pulse rate fluctuation range calculation means exceeds a predetermined criterion value, and the blood oxygen saturation fluctuation range calculated by the oxygen saturation fluctuation range calculation means. 2. The heart failure monitoring device according to claim 1, wherein the heart failure monitoring device outputs the heart failure alarm signal of the living body based on the fact that a predetermined threshold value is exceeded.