METHOD OF MEASURING THE RESPONSE OF A PATIENT TO HYPOXIC TRAINING

Abstract

A method of measuring a hypoxic session index as a measure of the response of a patient to hypoxic training with measurement of an index that characterizes the oxygen content in the patient’s blood is disclosed. The index is the oxygen saturation and/or the partial pressure of oxygen. The patient is first supplied with a normoxic gas mixture and then supplied with a hypoxic gas mixture. Subsequently, the patient receives a normoxic or hyperoxic gas mixture in a reoxygenation phase. The reoxygenation phase extends from the juncture from which the patient is supplied with the normoxic or hyperoxic gas mixture, over a defined hyperoxic period, wherein the index attains a hyperoxic reference value of the index, and over a subsequent predetermined concluding period. Differences between a data curve having the measurements of the index plotted against the respective measurement time and a predetermined reference curve ascertain the hypoxic session index.

Claims

1. A method of measuring a hypoxic session index (HSI) as a measure of the response of a patient to hypoxic training, with measurement of an index (KG) that characterizes the oxygen saturation in the patient’s blood, having the steps: I) supplying the patient with a normoxic gas mixture in an initial phase (AP) over a defined first period; II) determining the mean value of the index (KG) in the initial phase; III) supplying the patient with a hypoxic gas mixture in a hypoxic phase (HP) over a defined hypoxic period; IV) supplying the patient with the normoxic or hyperoxic gas mixture in a reoxygenation phase (RP) over a defined hyperoxic period and in a subsequent predetermined concluding period; V) plotting the index (KG) against time in the initial phase (AP), the hypoxic phase (HP) and the reoxygenation phase (RP) in the form of a data curve; VI) determining the hypoxic session index from a difference between the data curve and a predetermined reference curve (48); wherein the reference curve is a data curve which is determined for a reference person after steps I to V, or a data curve which is calculated by averaging data curves of a plurality of reference persons, wherein the data curves are determined after steps I to V for the reference persons.

2. The method according to claim 1, including setting a hypoxic cycle score (HCS) in the hypoxic phase (HP) for determining the hypoxic session index (HSI) by the following steps: VII) setting an HCS reference value of the index (KG) that is smaller than the mean value of the index (KG) in the initial phase (AP) and is greater than a hypoxic safety value; VIII) plotting the HCS reference value against time in the hypoxic phase (HP) as an HCS reference line of the hypoxic phase (HP); IX) determining an HCS determination area as an area between the data curve and the HCS reference line in the hypoxic phase (HP); X) determining an HCS reference area as an area between the reference curve and the HCS reference line in the hypoxic phase (HP); XI) determining an HCS area difference between the HCS reference area and the HCS determination area and/or an HCS area ratio as the ratio of the HCS determination area and the HCS reference area; XII) determining the value of the hypoxic cycle score (HCS) as a measure of the HCS area ratio and/or the HCS area difference.

3. The method according to claim 1, including setting a reoxygenation max score (RMS) in the reoxygenation phase (RP) for determining the hypoxic session index (HSI) by the following steps: XIII) setting an RMS safety time (RSP) after the start of the reoxygenation phase (RP); XIV) determining the RMS safety value (RSW) of the index (KG) associated with the RMS safety time (RSP) on the data curve in the reoxygenation phase (RP); XV) plotting the RMS safety value (RSW) against time (MT) in the reoxygenation phase (RP) as an RMS safety line (RSL) of the reoxygenation phase (RP); XVI. determining an RMS determination area (RBF.sub.1, RBF.sub.2) as an area between the data curve and the RMS safety line (RSL) in the reoxygenation phase (RP); XVII) determining an RMS reference area (RRF) as an area between the reference curve and the RMS safety line (RSL) in the reoxygenation phase (RP); XVIII) determining an RMS area difference between the RMS reference area (RRF) and the RMS determination area (RBF.sub.1, RBF.sub.2) and/or an RMS area ratio as the ratio of the RMS determination area (RBF.sub.1, RBF.sub.2) and the RMS reference area (RRF); XIX) determining the reoxygenation max score (RMS) as a measure of the RMS area ratio and/or the RMS area difference.

4. The method according to claim 1, characterized by determining a user reoxygenation potential (URP) as a measure of the difference between a predetermined reference reoxygenation max score (RMS) and the reoxygenation max score (RMS) determined in step XIX.

5. The method according to claim 3, including setting a dynamic score (DS) in the hypoxic phase (HP) for determining the hypoxic session index (HSI), having the steps: XX) determining a DS reference time (DRZ) at which the index (KG) in the hypoxic phase (HP) has dropped to a defined DS reference value (DBW), wherein the DS reference value (DBW) is smaller than the mean value of the index (KG) in the initial phase (AP) and greater than the hypoxic safety value; XXI) determining the dynamic score (DS) as a measure of the time difference between the DS reference time (DRZ) and a defined DS reference time interval.

6. The method according to claim 1, including setting a reoxygenation impulse score (RIS) in the reoxygenation phase (RP) for determining the hypoxic session index (HSI), having the steps: XXII) determining an RI reference time (RZP) to which the index (KG) in the reoxygenation phase (RP) has increased to a defined hyperoxic reference value (HB); XXIII) determining the reoxygenation impulse score (RIS) as a measure of the time difference between the RI reference time (RZP) and a defined RI reference time interval.

7. The method according to claim 1, including setting an oxygen recovery score (ORS) in the reoxygenation phase (RP) for determining the hypoxic session index (HSI) by the reoxygenation impulse score (RIS) and the reoxygenation max score (RMS), by averaging.

8. The method according to claim 1, including determining a baseline potential (BP) as a measure of the difference between a predetermined ideal value of the index (KG) of the oxygen saturation and the mean value of the index (KG) of the oxygen saturation from the initial phase (AP).

9. The method according to claim 1, including setting a lower boundary line and an upper boundary line, wherein the lower boundary line in the hypoxic phase (HP) shows smaller values of the index KG than the reference curve (48), and the upper boundary line shows greater values of the index (KG) than the reference curve at the respective same measurement times, wherein the boundary lines are determined from measurements of the index (KG) in one or more subjects, wherein only values of the index (KG) are considered for determining the hypoxic session index (HSI), which values are smaller than the value of the index (KG) in the upper boundary line and greater than the value of the index (KG) in the lower boundary line at the time of measurement of the respective value of the index (KG).

10. The method according to claim 1, including determining the hypoxic session index (HSI) by changing a pulse curve of the patient during steps III to V.

11. The method according to claim 10, including determining a heart rate relaxation score (HRS) by plotting a pulse curve against time during hypoxic training, having the following steps: XXIV) determining the mean value of the pulse (RR) in the initial phase (AP); XXV) plotting the mean of the pulse (RR) against the duration of the hypoxic training after the initial phase (AP) as a heart rate baseline parallel to the time axis, wherein the heart rate baseline forms a first leg of a relaxation measurement angle (RMW); XXVI) plotting a second leg of the relaxation measurement angle (RMW), wherein the second leg runs through the pulse (RR) at the start time (AZP) of the hypoxic phase (HP) and through the point of the pulse curve having the lowest value of the pulse (RR) after the initial phase (AP); XXVII. Determining the heart rate relaxation score (HRS) as a measure of the relaxation measurement angle (RMW).

12. The method according to claim 1, including one or more repetitions of steps III to V before determining the hypoxic session index (HSI) according to step VI.

Description

BRIEF DESCRIPTION OF THE INVENTION AND DRAWINGS

[0076] FIG. 1 schematically shows a device for measuring the response of a patient to hypoxic training;

[0077] FIG. 2 schematically shows an overview of entries measured by the device, through which an indication value comprising a hypoxic session index and/or a heart rate relaxation score as a measure of the response of a patient to hypoxic training is determined;

[0078] FIG. 3 schematically shows a method of measuring the hypoxic session index HSI;

[0079] FIG. 4 schematically shows a data curve of an index which is recorded in the method;

[0080] FIG. 5 schematically shows the data curve up to a DS reference time at which the index has dropped to a defined DS reference value;

[0081] FIG. 6 schematically shows a lower boundary line and an upper boundary line of the index in a hypoxic phase;

[0082] FIG. 7 schematically shows the data curve from the beginning of a reoxygenation phase up to an RI reference time at which the index has increased to a hyperoxic reference value;

[0083] FIG. 8 schematically shows the reference curve as well as a first data curve and a second data curve in the reoxygenation phase above an RMS safety value;

[0084] FIG. 9 schematically shows a pulse of the patient plotted against the measurement time in the form of a pulse curve;

[0085] FIG. 10 schematically shows the device with a display.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0086] FIG. 1 schematically shows a device 10 for measuring the response of a patient to hypoxic training. The device comprises a mask 12 for supplying a hypoxic gas mixture 14, a normoxic and/or hyperoxic gas mixture 16 to a patient (not shown).

[0087] In addition, the device has a controller 18 for controlling the device 10 and a finger clip 20 and a sensor 22, in particular, arranged in the finger clip 20, for measuring a pulse RR (see FIG. 9) of the patient and/or an index KG which characterizes the oxygen saturation of the patient’s blood, for example of the partial pressure of oxygen. The device 10 comprises a mobile application 24 for representing an indication value 26 by which the response of the patient’s body to hypoxic training is quantitatively detected.

[0088] FIG. 2 schematically shows an overview of the entries by which the indication value 26 is determined. These entries comprise a hypoxic session index HSI, a hypoxic cycle score HCS, a reoxygenation max score RMS, a user reoxygenation potential URP, a dynamic score DS, a reoxygenation impulse score RIS, an oxygen recovery score ORS, a baseline potential BP, a hypoxic baseline 50a, a heart rate baseline 66, a heart rate relaxation score HRS and/or a heart rate dynamic score HDS. These entries or indices can be shown in summarized form, for example in the form of averaging, or separately, for example in list form. The hypoxic session index HSI results, in particular, from one or more of the other aforementioned indices, for example by averaging these indices.

[0089] FIG. 3 schematically shows a method 100 of measuring the response of a patient to hypoxic training. In a first step I, the patient is supplied with the normoxic gas mixture 16 in an initial phase AP (see FIG. 4), in particular, in a rest position, over a defined first period, in particular over a first period of 20 seconds to 40 seconds, preferably 30 seconds. In a second step II, the mean value of the index KG in the initial phase AP is calculated. In a third step III, after the initial phase AP, the patient is supplied with a hypoxic gas mixture 14 over a defined hypoxic period in a hypoxic phase HP (see FIG. 4) until the index KG drops to a hypoxic value 82 which is greater than a defined hypoxic safety value 52 (see FIG. 4). In a fourth step IV, the patient (not shown) is supplied with a normoxic or hyperoxic gas mixture 16 over a defined hypoxic period in a reoxygenation phase RP (see FIG. 4), wherein the index KG attains a hyperoxic reference value HRW (see FIG. 4), and over a subsequent predetermined concluding period. In a fifth step V, the index KG is plotted against time in the initial phase AP, the hypoxic phase HP and the reoxygenation phase RP in the form of a data curve 46 (see FIG. 4). In a sixth step VI, the hypoxic session index HSI is determined from a difference between the data curve 46 and a predetermined reference curve 48 (see FIG. 4).

[0090] FIG. 4 schematically shows a data curve 46 of the index KG, which is recorded in the method 100 of measuring the hypoxic session index 26 against a measurement time MT in the initial phase AP, the hypoxic phase HP and the reoxygenation phase RP. Shown is also a predetermined reference curve 48 with which the data curve 46 is compared. Hypoxic baselines 50a of the reference curve 48, and hypoxic baselines 50b of the data curve 46 are obtained by plotting the mean value of measured values of the index KG against the measurement time MT in the initial phase AP of the method 100. In the reoxygenation phase RP, the reference curve 48 and the data curve 46 rise to the hyperoxic reference value HRW, which is shown here schematically as the same value for the reference curve 48 and the data curve 46. The hypoxic phase HP begins at the start time AZP. In the hypoxic phase, the patient is supplied with a hypoxic gas mixture 14 over a defined hypoxic period until the index KG drops to the hypoxic value 82 that is greater than the defined hypoxic safety value 52, which is plotted as a hypoxic safety value line 52 against the measurement time MT.

[0091] A predetermined HCS reference value of the index is smaller than the mean value of the index in the initial phase and is greater than the hypoxic safety value 52. The HCS reference value is shown as the HCS reference line 54 of the hypoxic phase against the measurement time MT. An HCS determination area 56 is defined as an area between the data curve 46 and the HCS reference line 54 in the hypoxic phase HP. An HCS reference area 58 is determined as an area between the reference curve 48 and the HCS reference line 54 in the hypoxic phase, the end of which is represented by a vertical line. The value of the hypoxic cycle score HCS is defined as a measure of the ratio and/or the difference between the HCS determination area 56 and the HCS reference area 58.

[0092] FIG. 5 schematically shows the data curve 46 in the initial phase AP and in the hypoxic phase HP (see FIG. 4) up to a DS reference time DRZ of the measurement time MT, at which DS reference time the index KG has dropped to a defined DS reference value DBW. The data curve 46 is shown schematically as a straight line in the initial phase AP and up to the time at which it starts to drop.

[0093] The DS reference value DBW is smaller than the mean value of the index KG in the initial phase AP and is greater than the hypoxic safety value 52 (see FIG. 4). The DS reference value DBW is, in particular, 96% to 98% of the mean value of the index KG from the initial phase AP. The time difference between the DS reference time DRZ and a defined DS reference time interval, in particular a DS reference time interval of 40 seconds to 50 seconds, is recorded as the value of the dynamic score DS, optionally divided by a numerical factor, for example 100. In case of negative time difference values and/or time difference values that are greater than a predetermined value, in particular, more than 184 seconds, the dynamic score DS is preferably set to zero.

[0094] Alternatively or additionally, the measurement time in the initial phase AP and the hypoxic phase HP may be divided into time intervals ZI, wherein each time interval ZI is assigned a hypoxic improvement potential, represented by different hatching in the time intervals ZI, such that a position of the DS reference time DRZ in a certain time interval corresponds to a certain hypoxic improvement potential.

[0095] FIG. 6 schematically shows a lower boundary line 60a and an upper boundary line 60b of the index KG in a hypoxic phase HP. The lower boundary line 60a in the hypoxic phase HP has, at the respective measurement time MT, smaller values of the index KG than the reference curve 48, and the upper boundary line 60b has greater values of the index KG than the reference curve 48. Only values of the index KG, which lie in the area BGF defined by the boundary line, are, in particular, connected to one another and used to determine the areas and indices mentioned in the application. The dashed line designated UG represents a lower limit of the index KG in the hypoxic phase HP that can be selected as a hypoxic safety value 52 (see FIG. 4).

[0096] FIG. 7 schematically shows the data curve 46 from the beginning of the reoxygenation phase RP up to an RI reference time RZP of the measurement time MT, at which RI reference time the index KG has increased to a defined hyperoxic reference value HB. The data curve 46 is schematically shown as a straight line from the beginning of the reoxygenation phase RP up until the time when the index KG starts to rise. The hyperoxic reference value HB is, in particular, 2% to 4% of the mean value of the index KG from the initial phase AP.

[0097] The time difference between the RI reference time RZP and a defined RI reference time interval, in particular an RI reference time interval of 40 seconds to 50 seconds, is recorded as the value of the reoxygenation impulse score RIS. In case of negative time difference values and/or time difference values that are greater than a predetermined value, in particular, more than 184 seconds, the reoxygenation impulse score RIS is preferably set to zero. Alternatively or additionally, the measurement time MT in the reoxygenation phase RP may be divided into time intervals ZI, wherein each time interval ZI is assigned a reoxygenation improvement potential, represented by different hatching, such that a position of the RI reference time RZP in a certain time interval ZI corresponds to a certain reoxygenation improvement potential.

[0098] FIG. 8 schematically shows a reference curve 48 as well as a first data curve 46a and a second data curve 46b in the reoxygenation phase RP above an RMS safety value RSW, shown as a dashed, horizontal RMS safety line RSL against the measurement time MT. The RMS safety value is a value of the index KG on the reference curve 48 at an RMS safety time RSP after the beginning of the reoxygenation phase RP.

[0099] In this case, the first data curve 46a reaches the RMS safety value RSW at an earlier time than the reference curve 48, and the second data curve 46b reaches the RMS safety value RSW at a later time than the reference curve 48. The horizontal line 62 schematically identifies a maximum value of the index KG, which the reference curve 48, the first data curve 46a and the second data curve 46b adopt in this exemplary embodiment in the reoxygenation phase RP. The cross-hatched area and the roughly hatched area below the reference curve together form the RMS reference area RRF. The reoxygenation max score RMS of the first data curve 46a is defined as the ratio of the total area of finely hatched area, cross-hatched area and roughly hatched area below the first data curve as the RMS determination area RBF.sub.1 and the RMS reference area RRF. The reoxygenation max score RMS of the second data curve is defined as the ratio of the roughly hatched area below the second data curve as the RMS determination area RBF.sub.2 and the RMS reference area RRF.

[0100] The respective user reoxygenation potential URP (see FIG. 2) of the first and second data curve is defined as a measure of the difference between a predetermined reference reoxygenation max score, in particular a value between 0.97 and 1, preferably 0.99, and the respective reoxygenation max score RMS of the first and second data curve determined in this way. The respective URP represents a measure of the difference between the first or second data curve 46a, 46b and the reference curve 48 in the reoxygenation phase RP.

[0101] FIG. 9 schematically shows the pulse RR of a patient (not shown) over the measurement time MT in the form of a pulse curve 64. The mean value of the pulse RR in the initial phase AP is plotted as a heart rate baseline 66 against the duration of hypoxic training after the initial phase parallel to the time axis of measurement time MT. Here, the heart rate baseline 66 forms a first leg 68a of a relaxation measurement angle RMW. A second leg 68b of the relaxation measurement angle RMW runs through the value of the pulse RR at the start time AZP of a first hypoxic phase HP and through the point 70 of the pulse curve 64 with the lowest value of the pulse RR after the initial phase AP. The heart rate relaxation score HRS is defined as a measure of the relaxation measurement angle RMW. In particular, steps II to V of the method have been repeated several times before the determination of the heart rate relaxation score, wherein the hypoxic phases HP, represented by non-hatched areas, and the reoxygenation phases RP, represented by hatched areas, alternate. Per cycle comprising a hypoxic phase and a subsequent reoxygenation phase, a heart rate dynamic score HDS is determined as the difference between the maximum value of the pulse RR in the cycle, indicated by a horizontal line 72a, and the minimum value of the pulse RR in the cycle, indicated by a horizontal line 72b.

[0102] FIG. 10 schematically shows the device 10 with a display 74. The display 74 has a first display panel 76a, where the oxygen O.sub.2 which is supplied to a patient over the measurement time MT is shown as an oxygen curve 78. Shown is, in particular, the varying amount of oxygen in the hypoxic phase HP and in the reoxygenation phase RP. Each hypoxic phase HP is followed by a reoxygenation phase RP. The pertinent values of the index which characterizes the oxygen saturation of the blood of a patient are shown in the form of a partial pressure of oxygen curve 80. The left scale of the first display panel 76a refers to the partial pressure of oxygen SpO2, stated in percent. The right scale refers to the amount of oxygen O.sub.2 in the gas mixture supplied, stated in vol%. The amount of oxygen O.sub.2 in the gas mixture supplied varies, in particular, between 7.5 vol% and 17 vol% in the hypoxic phase HP, and between 20 vol% and 35 vol%, in particular between 20.9 vol% and 32 vol%, preferably between 25 vol% and 30 vol%, in the reoxygenation phase RP. The horizontal axis indicates the measurement time MT during hypoxic training.

[0103] The display 74 has a second display panel 76b, where the values of the partial pressure of oxygen SpO2 are plotted as the partial pressure of oxygen curve 80, and the values of the pulse RR of the patient are plotted as a pulse curve 64 against the measurement time MT. The left scale of the second display panel 76b refers to the partial pressure of oxygen SpO2, stated in percent. The right scale refers to the pulse RR, stated in bpm (beats per minute). The horizontal axis indicates the measurement time MT during hypoxic training.

[0104] When viewing all figures of the drawing in combination, the invention relates to a method 100 of measuring a hypoxic session index HSI as a measure of the response of a patient to hypoxic training, with measurement of an index KG that characterizes the oxygen content in the patient’s blood. The index KG is, in particular, the oxygen saturation and/or the partial pressure of oxygen SpO2. The patient is first supplied with a normoxic gas mixture 16 in an initial phase AP. Subsequently, in a hypoxic phase HP, the patient is supplied with a hypoxic gas mixture 14 over a defined hypoxic period. Subsequently, the patient is supplied with a normoxic or hyperoxic gas mixture 16 in a reoxygenation phase RP, in particular over a period of 1 minute to 10 minutes. The reoxygenation phase RP extends from the time from which the patient is supplied with the normoxic or hyperoxic gas mixture 16, over a defined hyperoxic period, wherein the index KG attains a hyperoxic reference value HRW of the index KG, and over a subsequent predetermined concluding period. The hypoxic session index HSI is determined from the differences between a data curve 46, 46a, 46b having the measurements of the index plotted against the respective measurement time MT of the index KG and a predetermined reference curve 48.

TABLE-US-00001 List of reference signs: 10 Apparatus 12 Mask 14 Hypoxic gas mixture 16 Normoxic and/or hyperoxic gas mixture 18 Controller 20 Finger clip 22 Sensor 24 Mobile application 26 Indication value 45 Hear rate dynamic score 46, 46a, b Data curve 48 Reference curve 50a, b Hypoxic baselines 52 Hypoxic safety value line 54 HCS reference line 56 HCS determination area 58 HCS reference area 60a, b Lower, upper boundary line 62 Maximum value of the reference curve and of the first, second data curve in the reoxygenation phase 64 Pulse curve 66 Hear rate baseline 68a, b Leg 70 Point of pulse curve 64 with the lowest value of the pulse 72a, b Maximum, minimum value of the pulse 74 Display 76a, b Display panels 78 Oxygen curve 80 Partial pressure of oxygen curve 82 Hypoxic value 100 Method AP Initial phase AZP Start time of the first hypoxic phase BGF Area defined by the boundary line BP Baseline potential DBW DS reference value DRZ DS reference time DS Dynamic score HB Hyperoxic reference value HCS Hypoxic cycle score HDS Hear rate dynamic score HP Hypoxic phase HRS Heart rate relaxation score HRW Hyperoxic reference value HSI Hypoxic session index KG Index MT Measurement time ORS Oxygen recovery score RBF RMS determination area RIS Reoxygenation impulse score RMS Reoxygenation max score RMW Relaxation measurement angle RP Reoxygenation phase RR Pulse RRF RMS reference area RSL RMS safety line RSP RMS safety time RSW RMS safety value RZP RI reference time SBL Hypoxic baseline (SPO2 baseline) UG Lower limit of the index in the hypoxic phase URP User reoxygenation potential ZI Time intervals