JP3325273B2 - Monitoring device for patients with chronic congestive heart failure - Google Patents

Description

BACKGROUND OF THE INVENTION Congestive heart failure (CHF) results when the heart cannot contract with sufficient energy to meet the body's oxygen needs. Under these circumstances, to increase cardiac output, a self-regulating mechanism increases the filling pressure in the ventricle, thus elongating myocardial fibers at the onset of systole and increasing contraction strength. When the left and / or right filling pressure exceeds about 15 mmHg, blood components are forced from the vasculature into the interstitium, resulting in pulmonary edema (left heart failure) and / or peripheral edema and ascites (right heart failure). ) Occurs.
The end result is severe inactivity and even death.

In a portion of the population with heart disease of many different etiologies (about 600,000 Americans), the ability of the heart to meet the needs of the body is near the bottom line, resulting in chronic heart failure. For these patients, most can be stabilized by medication and dietary restrictions, and many are quite old, so slight fluctuations in physical activity, emotional stress or diet or medication. Noncompliance results in instability and acute heart failure requiring emergency hospitalization. In fact, hospitalization for heart failure is the second most expensive hospitalization diagnosis in the Medicare program.

The most reliable existing method for monitoring CHF is by directly measuring pulmonary artery and central venous pressure through a catheter inserted into the blood. This method, while very accurate, is clearly impractical outside the etiological environment. Other methods include observation of arterial pressure patterns (invasive or non-invasive) during Valsalva maneuver, flow measurement using Doppler ultrasound cardiography through the mitral annulus and in the pulmonary vein, There is observation of jugular vein distension, measurement of ankle dimensions and careful examination of body weight. The first two methods, with reasonable accuracy, require significant equipment and trained personnel, while the last three methods are rather unreliable for various reasons.

From Subramanyan et al. And other literature, both the resistive and reactive components of body impedance to relatively high frequency (50 kHz) current flow are sensitive to the amount of fluid retained by a CHF patient. Is shown. As the CHF dissipates, both resistance and reactance increase, as well as the electrical phase angle (tan-1
Reactance / resistance). Subramanyan et al., "Total Water Content in Congestive Heart Failure", Jour.Asso.Phys.I.
nd., September 1980, Vol. 28, p257-262. Luk
Others, including aski & Bolonchuk, are 50kHz or
The relationship between the component of the body's electrical impedance at any of the 1000 Hz and either the total body water or the extracellular fluid has been deduced. See Lukaski et al., "Estimation of body fluid volume using quadrupole bioelectrical impedance measurements", Aerospace and Environmental Medicine: 1988; 59; 1163-1169.

Nevertheless, there is a need for a practical and reliable method for monitoring the status of CHF patients outside the hospital environment. Such surveillance methods are intended for subramanya with the ultimate goal of providing intervention before the onset of acute CHF.
n et al. and Lukaski & Bolonchuk. A simple method to detect increased water content in CHF patients before hospitalization is needed and to allow timely adjustment of medication and / or diet to prevent the manifestation of acute heart failure Providing seems to be most desirable. The present invention fulfills these needs and provides other related advantages.

SUMMARY OF THE INVENTION The present invention aims to provide interventional treatment prior to the onset of acute congestive heart failure, with the aim of providing chronic congestive heart failure (CH
F) An "early warning" monitoring system to identify changes in the condition of the patient suffering. According to the present invention, a device for monitoring a patient suffering from chronic congestive heart failure includes
Included are electrodes applied to the location, means for passing current at one or more high frequencies between the electrodes, and then means for measuring current (I) and voltage (V). Congestive heart failure (CH) based on the measured current (I) and voltage (V)
F) Symptom values are calculated, and the calculated CHF symptom values are then compared to a reference value set when the patient is under known stable conditions, and the difference therebetween is within a set tolerance. Determine if there is.

In one preferred form of the invention, the device comprises electrodes applied to the two limbs of the patient and then means for passing a high-frequency current between the electrodes. Current (I), voltage (V)
And the phase angle (φ) are measured, and then a congestive heart failure (CHF) symptom value including resistance (R) and reactance (Zc) is calculated. The calculated CHF symptom value is then compared to a reference value, and an intervention is initiated when the difference between the calculated CHF symptom value and the reference value is outside a set tolerance. The method is repeated at intervals determined by whether an intervention was required. The calculated CHF signature value may further include an impedance (Z).

A decrease in either the phase angle (φ) or the calculated CHF symptom value in resistance (R), reactance (Zc) or impedance (Z) is one indicator of the need to initiate an interventional procedure. The allowable range from the reference value for the calculated CHF symptom value is about 5 percent (5%) for resistance (R) and impedance (Z), and for reactance (Zc).
10 percent (10%) and 20 percent (20%) for the phase angle (φ).

Calculated CHF signature values may also include total body water (TBW) and extracellular water (ECW). An increase in calculated total body water (TBW) or extracellular water (ECW) is one indicator of the need to initiate interventional treatment. An acceptable range from baseline is about 5 percent (5%) for total body water (TBW) and extracellular water (ECW). Total body water (TBW) can be calculated using the following equation:

TBW = .377 Ht ^{2 /} R + .14 Wt-.08 age + 2.9 gender + 4.65 (where gender is equal to 1 for males and 0 for females).

The extracellular water content (ECW) can be calculated using the following equation.

ECW = .189Ht ² /R+.52Wt-.0002Ht ² /Zc+1.03 calculated CHF symptoms value may further include a figure of merit indicating a hydration status of the patient. By way of example, this index number is the extracellular water content (E
CW). Lean mass (FFM) can be calculated using the following equation:

^{FFM = -15.26-.775 (Ht 2} /R)+.146Wt+.185Zc intervention when the ratio is greater than about 0.30 nonfat mass (extracellular water content for FFM) (ECW) is indicated. In addition, an increase in the number of indications of about one percent (1%) is another indicator of the need to initiate interventional treatment.

Other features and advantages of the present invention will become apparent from the following more detailed description read in conjunction with the accompanying drawings, which illustrate, by way of example, the principles of the invention.

BRIEF DESCRIPTION OF THE DRAWINGS The accompanying drawings illustrate the invention. In the drawings, FIG. 1 is the first of a two part flow chart illustrating the operation of a device for monitoring a patient suffering from chronic congestive heart failure embodying the present invention. FIG. 2 is also the second of a two-part flowchart illustrating the operation of the apparatus of the present invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS As shown in the drawings for purposes of illustration, the present invention relates to a patient suffering from congestive heart failure whose operation is indicated generally by the reference numeral 10 in FIGS. Novel device for monitoring a device. According to the present invention, this operation
10 generally comprises the steps of applying the electrodes to two locations on the patient's body and measuring the electrodes (I) and voltages (V) while passing current at one or more high frequencies between the electrodes. Thereafter, a congestive heart failure (CHF) symptom value is calculated based on the measured current (I) and voltage (V), and these values are compared with a reference value, and the difference therebetween is within a set tolerance. Is determined. If these differences fall outside the set tolerances, the intervention is initiated according to good medical practice. Thus, the present invention provides an "early warning" monitoring system for determining changes in the condition of a patient suffering from chronic congestive heart failure, with the ultimate goal of providing intervention before the onset of acute CHF.

Operation 10 of the present invention involves tracking the total impedance (Z), resistance (R), reactance (Zc) and phase angle (φ) of the body in an abulatory patient suffering from chronic congestive heart failure (CHF). However, the reduction of any or all of these "symptom values" is used to prevent the development of acute CHF. The measurement can be performed using a commercially available device for measuring body composition, such as that manufactured by RJL Systems of Clinton Twp, Michigan, or a similar device designed for this purpose. Large changes in the values of these parameters over time in the patient's body (eg, 5
Percent or more) would be considered an indicator of physical condition degradation. The electrodes can be placed at any two places in the body, but preferably are described in Subramanyan et al., "Total Water Content in Congestive Heart Failure", Jour. Asso. Phys. Ind., 198.
As described in September 0, Volume 28, p257-262,
It is positioned on either the wrist and ankle on the same side or the contralateral wrist and ankle. Measurements are typically made at high frequencies (20 kHz
Above-High sensitivity to total body water, or 20
below kHz-mainly sensitive to the volume of extracellular fluid)
Alternatively, it is performed at multiple frequencies.

Operation 10 of the present invention also includes utilizing the above-described technique applied to separate parts of the patient's body to separately track peripheral edema and pulmonary edema. For example, measuring and tracking the ankle-to-ankle impedance (Z) and its components will emphasize changes in peripheral fluids that are primarily indicative of right heart failure. The wrist-to-wrist impedance (Z) component will better indicate changes in lung fluid and left heart failure. Any change in these component impedance values will be used as an indicator of instability, indicating a change in therapeutic regimen.

Lukaski HC, & Bolonchu
k, WW “Estimation of body fluid volume using quadrupole bioelectric impedance measurements”, Aerospace and Environmental Medicine: 1988; 59,1163
Combined with body size and weight in a formula such as that described by -1169, the total body water (TB
W) and estimates for intracellular and extracellular water content (ECW). An increase of about 0.5 to 1 liter of the estimated amount of total or extracellular water from its baseline value will be used as one indicator for advanced heart failure and therapeutic intervention. Furthermore, combining the total and extracellular water estimates and the intracellular cell mass estimates into a single "differential number" form representing the hydration status of the patient can also be advantageously achieved in accordance with operation 10 of the present invention. . The change in the "explicit number" will be used as an indicator of the worsening condition of CHF patients. Standard readings are extracellular fluid (ECW)
Ratio of fat-free mass (FFM) or extracellular water content (ECW)
And the ratio of the total amount of water in the body. An index increase of about 1 percent (1%) is used as an indicator of a worsening condition. In addition, certain index numbers may themselves be used as indicators of congestive heart failure rather than their changes. For example, extracellular water content (ECW) and fat-free mass (F
If the ratio of (FM) is greater than about 0.30, it can be assumed that the patient is in a state of congestive heart failure.

Referring specifically to FIG. 1, this operation 10 begins by applying clinical criteria to assess the risk of acute heart failure (block 12). Factors to be estimated are the patient's history of hospitalization due to congestive heart failure (CHF), left ventricular systolic ejection fraction (EF-fraction of left ventricle emptied in each systole) and jugular vein distension. , Typical signs of CHF, including shortness of breath and terminal swelling. The patient is then evaluated to determine if it is classified as a high risk patient (block 14). High-risk patients have been in the past 3
Patients who have been hospitalized with CHF within months, patients who have been hospitalized with CHF last year and are exhibiting new jugular vasodilation, patients whose breathing is shortened at rest or with minimal exercise, and / or Patients with a systolic ejection fraction (EF) of less than 40 percent. If the patient is not classified as a high-risk patient, the physician can re-evaluate the timely diagnosis, for example, about every three months (block 16). On the other hand, when the patient is evaluated as a high-risk patient, the bioelectrical impedance analysis of the present invention is performed, and the health care provider determines the reference value set when the patient is under known stable conditions. The patient's congestive heart failure (CHF) symptom value can be determined for the purpose of comparing (block 18).

In a preferred embodiment, two electrodes are attached to each of the two limbs (block 20). Two more distal electrodes (ie, hands and feet) are used to inject electrode (I), while two more proximal electrodes (ie, wrists and ankles) measure voltage (V). Used for However, the contact impedance is much lower than the body impedance (Z) (ie, << 500
If the electrodes have sufficient surface area (Ω), a single electrode on each of the two limbs can be used for both current injection and voltage measurement. Any pair of limbs (right arm vs. left leg, right arm vs. left arm, etc.) or multiple pairs can be used,
The result is calculated for each pair. In a preferred embodiment, the electrodes are mounted at the lower left and upper right ends.

Once the electrodes are properly attached to the patient,
A high frequency current is passed between the electrodes (block 22). A typical (preferred) current is 800 μamp at 50 kHz. Up to 5
It is possible to use a current of ma as well as any single frequency from 10 kHz to 100 kHz. Alternatively, one is 10kH
Less than z (eg 1kHz), one more (eg 100kHz)
Are available. As the high frequency current is passed between the electrodes, current (I) (block 24) and voltage (V) and measured current (I)
The phase angle (φ) between block and voltage (V) (block 26) is measured. At this point, the voltage (V) and current (I) are
It can be measured using any conventional technique, analog or digital.

As is known to those skilled in the art, the delay between voltage and current at the zero crossing (current lags voltage) has the same relationship to phase angle (φ) and 360 ° over wavelength period. In other words, td is the time during which the current (I) is delayed by the voltage (V), and (T) is the wavelength period (reciprocal of the frequency).
And the phase angle (φ) is equal to 360 (td / T). Five
For a 0 kHz current, T = 1 / 50,000 = 20 μs.

Thus, the current (I), voltage (V) and phase angle (φ)
, The congestive heart failure (CHF) symptom value can then be calculated (blocks 28, 30 and 32). As illustrated in block 28, the calculated first symptom value includes:
It includes impedance (Z), resistance (R), and reactance (Zc). The impedance (Z) is obtained by dividing the rms voltage by the rms current. The resistance (R) is the impedance (Z) multiplied by the cosine of the phase angle (φ), that is, R = Zcosφ. Reactance (Zc)
Is the capacitance of the impedance (Z), and is determined by multiplying the impedance (Z) by the sine of the phase angle (φ). That is, Zc = Zsinφ.

As exemplified in block 30, the patient's total body water (TBW), extracellular water (ECW) and lean mass (FF)
M) can be calculated to obtain CHF symptom values. Total water content (TBW) and extracellular water content (ECW) were determined by Lukaski HC
& Bolonchuk WW "Estimation of body fluid volume using quadrupole bioelectrical impedance measurements", Aerospace and Environmental Medicine: 1
988; 59; 1163-1169. These equations are as follows.

TBW = .377Ht ² /Rtasu.14Wt-.08_Nenrei +2.9 gender Tasu4.65 (where gender 1 for males is equal to 0 for women), and ECW = .189Ht ² /R+.52Wt −.0002Ht ² /Zc+1.03 where Ht is the height (cm) of the patient, and Wt is the weight (kg) of the patient. The fat-free mass (FFM) is calculated from the formula provided in Huges, VA and Evans WJ, "Assessment of Fat-Free Mass in Elderly Using Bioelectrical Impedance," Fed. Proc 1987: 46 (abstract). Can be calculated as follows.

^{FFM = -15.26-.775 (Ht 2} /R)+.146Wt+.185Zc other aspects of these formulas are also available as well as formulas for the two frequency analysis.

Block 32 shows the deduction of a "differential number" from the ratio of extracellular water content (ECW) to lean mass (FFM).

When starting the monitoring program, it is necessary to set a reference value for the calculated CHF symptom value (blocks 28-32). The reference value is preferably measured when the patient is under known stable conditions, such as when leaving the hospital and / or when incorporated into a monitoring program. If the reference values are being set (block 34), they are stored for further reference (block 36). The stored reference values are typically patient weight (Wt), calculated impedance (Z), resistance (R), reactance (Zc), phase angle (φ), total body water (TBW), Extracellular water content (ECW), non-fat mass (FF
M) and the ratio of extracellular water to non-fat mass (ECW
/ FFM). Once the reference value is set and stored (block 36), there is a delay (block 38) before repeating the bioelectrical impedance analysis (18). The preferred delay before repeating the measurement is 1-2
Week.

Subsequent analysis (18) follows the same process steps 20-32 as described above. However, since the reference values have already been set and stored (34, 36), the newly calculated symptom values (28, 30 and 32) are then compared with the previously set reference values (block 40). ), It is determined whether the difference therebetween is within a set tolerance (block 42). In a preferred embodiment of the present invention, a decrease in either the phase angle (φ) or the calculated CHF symptom value in resistance (R), reactance (Zo) or impedance (Z) requires the intervention device to be triggered. It is an indicator of gender. The tolerances from the reference values are about 5 percent (5%) for resistance (R) and impedance (Z), about 10 percent (10%) for reactance (Zc) and about 20 percent (20%) for phase angle (φ). %). Calculated increases in total body water (TBW) or extracellular water (ECW) are also indicators of the need to initiate interventional treatment. The acceptable range from baseline for such calculated CHF symptom values is:
It is about 5 percent (5%) for both total body water (TBW) and extracellular water (ECW) calculations. With respect to the descriptive number deduced from the ratio of extracellular water content (ECW) to lean mass (FFM), if such ratio is greater than about 0.30 and / or about 1 percent (1%) If an increase is present, an intervention is indicated.

If the calculated CHF symptom value is within the set tolerance, there is simply a delay (38) before repeating the measurement.
In particular, for patients whose measurements fall within the acceptable range, the preferred delay before repeating the measurement is 1-2 weeks. For patients with such a designated medical history, the frequency of monitoring can be increased or decreased.

For patients whose measurements fall outside the acceptable range, intervention is indicated (block 44). The intervention is based on medical judgment and does not form part of the present invention. This may include advice such as reducing the amount of salt in the diet or reducing activity. The use of diuretics and / or angiotensin converting enzyme inhibitors may be increased. In severe cases, intravenous diuretics can be initiated as well as intravenous agents (myoconstrictors such as dobutamine) to increase the pumping action of the heart, or the patient may be asked to be hospitalized. May be advised. Patients undergoing stabilization through therapeutic intervention are monitored more frequently and thus have a delay (38) of one day or two before repeating measurements.
Should be reduced to days.

While particular embodiments of the present invention have been described in detail, various modifications can be made without departing from the spirit and scope of the invention. Accordingly, the invention is not limited except as by the appended claims.

Continuation of the front page (56) References JP-A-9-220209 (JP, A) JP-A-52-149889 (JP, A) JP-A-59-500700 (JP, A) (58) Fields investigated (Int) .Cl. ⁷ , DB name) A61B 5/053

Claims (36)

(57) [Claims] An apparatus for monitoring a patient suffering from chronic congestive heart failure, comprising: an electrode applied to two limbs of the patient; a means for passing a high frequency current between the electrodes; Means for measuring the voltage (V) and the phase angle (φ) between the voltage (V) and the measured current (I);-stasis based on the measured current (I), voltage (V) and phase angle (φ). Means for calculating a congenital heart failure (CHF) sign value; and means for comparing the calculated CHF sign value with a reference value to determine whether the difference therebetween is within a set tolerance. . 2. The apparatus of claim 1 further comprising means for setting a reference value at a time when the patient is under known stable conditions. 3. The apparatus of claim 2, further comprising means for initiating an intervention during the comparison when the difference between the calculated CHF symptom value and the reference value is outside a set tolerance. 4. The apparatus of claim 3, including means for repeating monitoring of a patient with chronic congestive heart failure at intervals determined by whether an interventional procedure was required. 5. The apparatus of claim 3, wherein the calculated CHF symptom values include resistance (R) and reactance (Zc). 6. The apparatus of claim 5, wherein the calculated CHF symptom value includes an impedance (Z). 7. A decrease in either the phase angle (φ) or the calculated CHF symptom value of the resistance (R), reactance (Zc) or impedance (Z) is one of the necessities of initiating the intervention procedure. 7. The device of claim 6, wherein the device is an indicator. 8. An allowable range from a reference value for a calculated CHF index value is about 5% (5%) for resistance (R) and impedance (Z), and 10% (5%) for reactance (Zc). The apparatus according to claim 7, wherein the phase angle (φ) is 20 percent (20%). 9. The calculated CHF symptom value is calculated based on the total body water content (TB).
6. W5 and extracellular water content (ECW).
An apparatus according to claim 1. 10. A body total water content (TBW) is, TBW = 0.377Ht ² /Rtasu0.14Wt-0.08_Nenrei +2.9 gender Tasu4.65 (Note gender for men 1 Here, 0 for women equal), is calculated using the expression, extracellular water content (ECW) is calculated using the expression ECW = 0.189Ht ² /R+0.52Wt-0.0002Ht ² /Zc+1.03, patients Ht here 10. The apparatus of claim 9, wherein the height, Wt, is the patient's weight. 11. The device of claim 9, wherein an increase in calculated total body water (TBW) or extracellular water (ECW) is one indicator of the need to initiate an interventional procedure. 12. The method according to claim 11, wherein the acceptable range from the baseline for the calculated CHF sign value is about 5 percent (5%) for total body water (TBW) and extracellular water (ECW). The described device. 13. The apparatus of claim 5, wherein the calculated CHF symptom value comprises a metric indicative of the patient's hydration status. 14. The characteristic number is deduced from the ratio of extracellular water content (ECW) to lean mass (FFM).
An apparatus according to claim 1. 15. extracellular water content (ECW) is calculated using the expression ECW = 0.189Ht ² /R+0.52Wt-0.0002Ht ² /Zc+1.03, nonfat mass (FFM) is FFM = -15.28 Calculated using the formula −0.775 (Ht ² /R)+0.146Wt+0.185Zc, where Ht is the patient's height and Wt is the patient's weight.
15. The device according to 14. 16. The device of claim 14, wherein an intervention is indicated when the ratio of extracellular water content (ECW) to lean mass (FFM) is greater than about 0.30. 17. The method of claim 14, wherein an increase in the number of indications of about one percent (1%) is an indication of the need to initiate an intervention.
An apparatus according to claim 1. 18. Apparatus for monitoring a patient suffering from chronic congestive heart failure, comprising: electrodes applied to two places on the patient's body; means for passing current at one or more high frequencies between the electrodes; Means for measuring the current (I) and voltage (V) at each frequency; means for calculating a congestive heart failure (CHF) sign value based on the measured current (I) and voltage (V); and Means for comparing the above CHF symptom value to a reference value and determining whether a difference therebetween is within a set tolerance. 19. A means for setting a reference value determined at a point in time when the patient is under known stable conditions, wherein during comparison the difference between the calculated CHF symptom value and the reference value is outside the set tolerance. Claims comprising means for initiating an intervention at one time and means for repeating monitoring of a patient with chronic congestive heart failure at intervals determined by whether the intervention was required.
19. The apparatus according to 18. 20. The calculated CHF symptom value is determined by calculating the total body water content (T
BW) and extracellular water content (ECW), and an increase in the calculated total body water (TBW) or extracellular water (ECW) is one indicator of the need to initiate interventional treatment. 20. The device according to claim 19. 21. The method according to claim 20, wherein the acceptable range from the baseline for the calculated CHF symptom value is about 5 percent (5%) for total body water (TBW) and extracellular water (ECW). The described device. 22. Calculated CHF indication values include lean mass (F
FM) to the ratio of extracellular water content (ECW) and includes a reading that indicates the patient's hydration status;
The device according to claim 20. 23. When the ratio of extracellular water content (ECW) to non-fat mass (FFM) is greater than about 0.30, or when there is an increase in the index number of about 1 percent (1%), 23. The device of claim 22, wherein an intervention is indicated. 24. The measured current (I) at each frequency
Means for measuring the phase angle (φ) between the voltage and the voltage (V), and the calculated CHF symptom values are resistance (R), reactance (Z
20. The device according to claim 19, comprising c) and impedance (Z). 25. CHF for calculating phase angle (φ) or resistance (R), reactance (Zc) or impedance (Z)
25. The device of claim 24, wherein any decrease in the symptom value is one indicator of the need to initiate an intervention. 26. The tolerance from the reference for the calculated CHF index value is about 5 percent (5%) for resistance (R) and impedance (Z), and reactance (Zc).
25. The apparatus of claim 24, wherein 10% (10%) and 20% (20%) for phase angle (φ). 27. Apparatus for monitoring a patient suffering from chronic congestive heart failure, comprising: an electrode applied to two limbs of the patient; a means for passing a high frequency current between the electrodes; Means for measuring the voltage (V) and the phase angle (φ) between the voltage (V) and the measured current (I); based on the measured current (I), voltage (V) and phase angle (φ) , Resistance (R) and reactance (Zc)
Means for calculating a congestive heart failure (CHF) sign value comprising:
And-means for comparing the calculated CHF symptom value to a reference value and determining whether the difference therebetween is within design tolerances; during the comparison, the difference between the calculated CHF symptom value and the reference value. Means for initiating an intervention when is outside a set tolerance, means for repeating monitoring of a patient suffering from chronic congestive heart failure at intervals determined by whether or not an intervention is required. . 28. The apparatus of claim 27, further comprising means for setting a reference value at a time when the patient is under known stable conditions. 29. The calculated CHF signature value includes an impedance (Z), a phase angle (φ), or a calculated CHF of resistance (R), reactance (Zc) or impedance (Z).
29. The device of claim 28, wherein any decrease in the F-symptom value is one indicator of the need to initiate an intervention. 30. The tolerance from the reference for the calculated CHF index value is about 5 percent (5%) for resistance (R) and impedance (Z), and reactance (Zc).
30. The apparatus of claim 29, wherein the device is 10 percent (10%) and 20 percent (20%) for the phase angle (φ). 31. The calculated CHF symptom value is defined as total body water (T
BW) and extracellular water content (ECW), and the calculated increase in total body water (TBW) or extracellular water (ECW) is one indicator of the need to initiate interventional treatment , Claim 27
An apparatus according to claim 1. 32. The total water content (TBW) in the body is as follows: TBW = 0.377Ht ² /R+0.14Wt−0.08 years old + 2.9 gender + 4.65 (where gender is 0 for males and 0 for females) equal), is calculated using the expression, extracellular water content (ECW) is calculated using the expression ECW = 0.189Ht ² /R+0.52Wt-0.0002Ht ² /Zc+1.03, patients Ht here The height of the patient, Wt is the weight of the patient.
The device according to 31. 33. The method of claim 31, wherein the acceptable range from the baseline for the calculated CHF symptom value is about 5 percent (5%) for total body water (TBW) and extracellular water (ECW). The described device. 34. The apparatus of claim 27, wherein the calculated CHF symptom value includes a metric indicative of the patient's hydration status. 35. The index number is deduced from the ratio of extracellular water content (ECW) to lean mass (FFM), wherein the ratio of extracellular water content (ECW) to lean mass (FFM) is greater than about 0.30. 35. The apparatus of claim 34, wherein at that point the intervention is indicated and an increase in the index of about 1 percent (1%) is an indication of the need to initiate the intervention. 36. The extracellular water content (ECW) is calculated using the following equation: ECW = 0.189Ht ² /R+0.52Wt−0.0002Ht ² /Zc+1.03, and the fat-free mass (FFM) is FFM = −15.28. -0.775 (calculated using the expression Ht ² /R)tasu0.146Wttasu0.185Zc, where Ht is the patient's height, Wt is the weight of the patient, claim
The device according to 35.