DE2812447A1 - Treatment chamber for bronchial complaints - has air conditioned hood of min. volume with ergometer, monitoring and control system - Google Patents

Abstract

The treatment chamber for bronchial complaints is formed by a transparent housing (1) completely enclosing the patient with appts. for stabilising the climatic conditions inside. A set of electrodes (22) connected to the patient monitors his condition and supplies signals to a control system which operates the supply or delivered by a breathing tube (28) as well as the air circulating system and the heating and humidity control systems. At the end near the patient's head is an air delivery unit (11) at the other end is an extraction system (15) with a control valve (17) and an extraction fan (16). The valve is a Laval jet. The patient's feet operate an ergometer (7). The construction gives a min. vol. having a half elliptical shape which decreases in side towards the head end.

Description

Name: full body plethysmograph

The invention relates to a whole body plathysmooraphen, consisting from a chamber that encloses the test subject airtight, one inside the chamber on the Subjects connected breathing tube with a pnaumatachograph and a chamber wall pnaumotachograph for measuring the chamber pressure or volume changes as well as connected to a computer Measuring devices for individual observers of the pulmonary foundation test.

As part of the pulmonary function test, it is necessary to diagnostic to measure decisive values of the breathing mechanics.

This includes, among other things, the determination of the bronchial flow resistance, the intrathoracic gas volume and the gas dynamic work of breathing.

If the intra-pulmonary pressure conditions accelerate the The respiratory flow in or out of the lungs and the respiratory flow can be measured determine whether the bronchial flow conditions are obstructed or whether to high (pathological) pressures in the lungs to overcome flow resistance, z.9. if you have bronchitis.

The volume of gas in the lungs can be determined by the fact that an in A test person located in a closed chamber is tried against a closed one Inhale and exhale tube.

The resulting pressure changes in the lungs are simultaneous with the pressure or volume changes occurring in the chamber on one XY recorder recorded.

Since the chamber volume, the pressure or volume changes in the chamber and the changes in intra-pulmonary pressure, measured as exhalation pressure (mouth pressure) when the breathing tube is closed, are known, can be derived from the Steioung of the recorded Measurement curve determine the intrathoracic gas volume based on the Boyle-Mar law.

A distinction is made between volume constant with the well-known whole-body plethymographs and constant pressure systems for determining these lung function values.

A plethysmograph of constant volume consists of one of the test floors receiving, airtight chamber, in which breath synchronously through dis Chest movements of the test person the respective intra-alveolar pressure in the lungs is determined by the fact that the pressure change in the interior of the chamber during inhalation and exhalation is measured and registered.

A constant pressure plethysmograph consists of an airtight, a test subject receiving chamber, in the wall of which a pneumotachograph is installed which registers the amount of air over time that is caused by the thoracic movements the subject is displaced or sucked in.

Using suitable conversion factors that take into account the chamber volume, can use a computer to make the respective inversely proportional to the change in volume intra-alveolar pressure changes within the lungs can be determined (cf.

H. Matthys, "Lung Function Diagnostics Using Whole-Body Plsthysmography" F.K. Schattauer-Verlag, Stuttgart - New York 1972).

The known devices are not particularly suitable for Lung function test in one kilometer of subjects who are under physical strain, because that due to changes in the composition of the cabin air, in particular the rise in temperature, the rise in relative humidity and the content of coblenic acid as well as the decrease in the oxygen concentration, longer-lasting examinations not possible with different high load levels.

In known chambers with volumes of approx. 700-1000 l, the result is in the case of test persons in the resting position, a temperature increase within 5 minutes of 1.4 K. If you consider that a temperature rise of 1 K already creates a volume - an enlargement of 2500 -3400 ml argues, this represents a measured value of 2U ml already represents a considerable deficit.

The humidity inside the chamber increases within 17 minutes from 50 to 100 @, which also leads to an undesirable one which falsifies the measurement results Changes in pressure or volume leads and, in addition, places considerable strain on the test subject.

When the test person is at rest, the oxygen decreases within 20 minutes by 1 d, o, d.-h. From 21 vol% to 20 vol%. Finally the carbon dioxide rises in 25 min. from 0.03 vol / to 1.0 vol a and affects the respiratory center of the test person an indispensable increase in the minute ventilation.

If these climate changes already occur in test subjects, so there are even stronger and more rapid changes with physical exertion. Mathematically, this results in an increase with a physical load of 320 W. the energy consumption by approx. 1600 W and an increase in perspiration of 0.13 on 2014 1 / n. While the relative humidity in a chamber is 1000 1 content with a sweat formation of 0.05 l / h only in 17.0 min from 50 to 100 2 increases, the same change in humidity results in exposed test persons with a Sweat formation of 2.5 1/5 already within the short period of 0.3 min.

A constant load of 150 W resulted in a temperature increase in the chamber of more than 4 K within 6 minutes each time relative Humidity from 50 to 100 within less than 1 minute % The oxygen content decreased by 1% after every 4.5 minutes, while the carbonic acid concentration every 5 min increased by 1 o.

The present invention is therefore based on the object To create whole-body plethysmographs with which to a large extent flawless lung function measurements Can be done in patients when they are at rest or at rest any physical, measurable stress condition. The above should be Eliminated the disturbance variables mentioned and those with the well-known whole-body plethysmogphs associated disadvantages avoided.

The solution to the problem posed is according to the invention, that the chamber is used to stabilize the climatic conditions inside the chamber has a ventilation device and means for heat and humidity control.

With this solution, the invention is deliberately based on the known volume constant System off and achieves suppression through constant adequate ventilation of the climate disturbance variables mentioned above.

Further features of the invention emerge from the subclaims.

The invention is based on the drawing of an exemplary embodiment explained in more detail and specifically show: FIG. 1 a schematic representation in perspective of a whole-body pair plethyamograph according to the invention, FIG. 2 is a schematic Representation of the flow course in a whole-body plethysmograph according to FIG Invention, FIG. 3 shows a cross-sectional view through the chamber of the whole-body plethysmograph 1 and 4 are a circuit diagram.

The whole-body plethysmograph according to the invention essentially consists from an airtight lockable chamber 1.

This in turn consists of an elongated base 2 made of good thermal conductivity Material e.g. light metal, qgf. also with heat dissipation fins or fins and is in the manner of an X-ray table preferably up to 90 ° around a transverse to it Horizontal axis 3 arranged in the longitudinal direction is designed to be pivotable. On the pad is detachable one preferably made of transparent, pressure-resistant material, e.g. polyacrylic glass or

Like. Existing hood 4 attached. This is centered on one long side arranged joints rotatable or pivotable with the hotel location 2 and is connected by means of holding magnets, not shown, on the other long side pressed against the base 2. Between the hood 4 and the base 2 are common Seals arranged.

To enable the hood 4 to be opened and closed easily, it is not shown in detail at least on one end wall 10 or 13 of the chamber 1 Arranged toggle quick-action gear 5, the opening of the hood 4 by about 70 ° allows.-In the chamber 1 are on the base 2 for the test person 20 a support surface 6, which is expediently designed as a slatted frame, e.g. made of wood is and a vibration-free attached bicycle ergometer unit 7 of known design.

The hood 4 is designed so that it has the smallest possible volume but is large enough to accommodate subject 20 and the required To accommodate measuring devices.

In order to ensure that the hood 4 is as pressure-resistant as possible, this has an essentially one in the area of the legs and the upper body of the test subject 20 semi-elliptical (8) and one in the head, neck and shoulder area of the test subject essential semicircular cross-section 9.

On the head-side end wall 10 of the chamber 1 there is one Air inlet opening 11 to which a pneumotachograph 12 is connected. On the foot side End wall 13 of the chamber 1 is provided with an exhaust air opening 14 to which an exhaust air line 15, which is connected to a suction fan 16. In front of the suction fan 16 is a control valve 17, which consists essentially of a nozzle, preferably an adjustable or interchangeable Laval nozzle.

The control valve 17 is designed so that in the narrowest nozzle cross-section in a known way the speed of sound prevails.

As is well known, an overhead speed then forms behind the nozzle of the flowing medium, which is not used here any further. The nozzle arrangement forms an aerodynamic blockage of the exhaust air line, so that pressure surges occur the conditions in front of the nozzle, i.e. in particular in chamber 1 as well as the constant Flow have no influence.

Because of the low critical pressure ratio, the use a small exhaust fan possible. It is advantageous to exchange different ones Nozzle sizes provided so that constant flow rates of any given Size can be provided.

As long as the critical pressure ratio is maintained, there is sound velocity in the narrowest cross-section of the nozzle, so that the pump-side or pressure waves cannot penetrate this cross-section. As the sound speed only from the root of the absolute temperature and the ratio of the specific Heat (adiabatic exponent) of the gas is dependent, remain at constant temperature inside the chamber the speed of sound and also the gas flow rate or chamber flow rate the same for the respective constant bottom cross-section. You can also use the gas constant and the specific heat when using ambient air is considered to be constant will.

With the aforementioned arrangement, the gas flow can be as large as possible Constancy without special control devices in the simplest and most effective way Dosing wisely.

Since the air is injected at the head end of the chamber 1 through the end wall 10 and is sucked off at the foot end through the end wall 13 at a constant speed, this results primarily in a longitudinal flow 19 (FIG. 2) through chamber 1. @@ this longitudinal flow is not able to fully compensate for climatic disturbances is a facility intended to generate a general air mixture. To this end are on the one inner longitudinal side of the base 2 several circulating air fans 18, if necessary also add -he guiding devices are provided, which have a transverse or swirl flow, which is indicated by arrows 21 in FIG. 2.

The improvement of the flow at interfaces, especially in the area The base 2 made of thermally highly conductive material causes a favorable Dissipation of the heat generated on the body surface, as well as a considerable amount Reduction of perspiration. The formation of the support 6 prevents rust as a slat also the accumulation of sweat fluid on the back and ensures an even Sweat evaporation from the body.

Trials showed that with constant physical exertion of 150 W for more than 6 minutes, the temperature rise until thermal equilibrium is reached was a maximum of 1.2 K, the thermal time constant being approx. 15 s.

The Pro band 20 located in the chamber 1 is connected to a conventional electrocardiogram (EKG) 35 connected via body lead electrodes 22. Furthermore, it is a common one Blood pressure measuring device 36 is provided with an arm cuff. The ergometer unit 7 is on a known edge. Device 23 connected for load adjustment.

Furthermore, a movable holder 24 is provided on which a Pneumotachoaraph 25 is fastened, in turn directly with an in des Mued des Prahanden 29 introduced Atemroht 26 is connected, over ossienete eitusen is the Bneumotachoeraph 25 with Meleinrichtyaren 31, 32, 33 for the determination of the oxygen and colenic acid fractions (31) as well as the flow medce of the breathing air (32) and the atmospheric pressure (33). In the Atemluftieituss a shutter 27 is also closely arranged, which is useful with an electronic program control unit 49 is connected. The shutter 27 is used to to close the breathing tube at certain times, the chamber wall pneumotacfh @@ raph is with a measuring device 30 for determining the general Kemmer flow rate tied together.

Finally, one is insertable into the subject 20's oseophaous Provide balloon probe 28, which is attached to a pressure measuring device 34. The measuring instruments 30 -36 are in turn connected to other electronic computer units, which emerges from the circuit board of the Fie. 4 eroeben.

--Fig 4 shows in the upper part schematically the chamber 1 with the in the accommodated essential measuring points, namely the breathing tube 26 with the Pneutotachoaraphes 27 and the outgoing measuring lines, the balloon probe 28 and the chamber wall pnesmatachograph 12th

Bigen is a major disruptive factor in whole-body plethyamography the air breathing in the chamber due to the heat emission of the test subject 20.

The energy expenditure of the human body, which is approximately at rest 85 W and with a load of e.g. 150 W is about 700 W. causes an increase in temperature of approx. 1.5 K at rest and approx. 4 K under load. With a chamber volume of 1000 1 at 293-K, this increase in temperature causes a volume increase of 3.4 1, d. H. a multiple of the measured value, which is of the order of 20 ml.

The known compensating means are in the form of high pass filters insufficient. It is therefore necessary to tune the mean chamber temperature, whereby it is not sufficient to measure the chamber temperature at only one point. In order to there would be temperature deviations occurring elsewhere as a result of radiation, flow influences etc. not sufficiently covered.

The different order of magnitude of measure and interference signal, namely 0.02 1 on the one hand and 3.4 1 on the other hand do an analog calculation in terms of circuitry impossible, since the usual computer amplifiers are not intended for such translations are.

To record the temperature gradient required for compensation between the interior of the chamber 1 and the environment are therefore 2 measuring loops 37, 3B made of thin copper wire. A measuring loop 37 is within the chamber 1 expediently below the support 6 of the test subject 20 in the blowing area of the circulating air fan 18 arranged. These circulate the chamber volume once every 5D s. Local temperature increases can only have local increases in resistance of the measuring loop, so that from the Change in resistance of the measuring loop results in the mean temperature rise.

The measuring loop 38, on the other hand, is arranged below the base 2 and records the ambient temperature that is important for the temperature gradient.

Because of the different magnitudes of the measured values, will not the entire interfering signal but only the change in the interfering signal over time determined. This value is in the same order of magnitude as the measurement signal and can therefore easily with the change in chamber volume over time i.e. offset against the flow rate of the chamber.

According to FIG. 4, the measuring loops 37, 38 are part of a suitable measuring bridge @@ a temperature compensation device 39. The bridge voltage is the temperature difference proportional between chamber 1 and the environment. A differential amplifier (not shown) follows and a low-pass filter to suppress high-frequency interference. A differentiator forms the time derivative of the temperature gradient and feeds the obtained Correction signal in the measuring line for the flow values of the chamber behind the device 30 a.

The measuring devices 30, 32, 33 and 34 consist essentially of each from a pressure transducer 42 and a carrier frequency measuring amplifier 43.

To compensate for changes in pressure in the ambient atmosphere is still a further measuring device 47 is provided, the output of which is also connected to the measuring line the device 30 is connected to this measuring line, which the general flow values reproduces the chamber 1 can optionally be connected to an integrator 44 which at the output 50 supplies the flow volume, while at the output 51 the temporal Flow value appears. Both values are proportional to the alveolar pressure.

The device 32 for measuring the respiratory flow is via an integrator 45 connected to the output 55, which indicates the tidal volume. The integrator immediate output 56 directly indicates the respiratory flow.

An inversion point generator 46 is connected in parallel with the integrator 45, which acts on a shutter control 47, which at the same time with a remote control 48 provided program automatic 49 is connected, in which the measured values of the outputs 50, 55, 56 and a time value 59 can be fed in with a clock 62.

A computer 63 is also connected to the respiratory flow measuring line, the correction values with regard to the subject's body temperature etc. to the measuring point 50 forwards.

Suitable electronic devices of a known type can also be used from the respiratory flow measurement line at the outputs 52 to 54, the tidal volume, minute volume and measure the respiratory rate.

The XY recorder is at the outputs 57, 58 of the automatic program connected.

With the described whole-body plethysmograph you can simultaneously a cardiopulmonary function analysis at both calm as also physically loaded test persons in every body position from 0 -90 °, i.e. in Perform the gender, seated, or upright posture.

With regard to the breathing technique, the pronchial flow resistance, the oasHynamic atewarbait, the intrathoracic Sasvolumn and 99fl at the same time The work of breathing is determined by measurements that are performed at any strength or length of physical activity Load with known V @ rrichtunnen were not possible up to now.

In addition to these respiratory mechanical values, in the area of spiroergometry the tidal volume, the minute volume and the respiratory flow rate, the oxygen uptake and measure carbon dioxide output and from this the respiratory quotient (C02 output: 02 uptake), the respiratory equivlent, i.e. the inhalation volume required for the uptake of 1 ml of 02 in the blood is necessary And the ratio of oxygen uptake: pulse rate determined. Finally, in a known manner, the cardiac measured values of the connected Electocardiogram, blood pressure, pressure values in the arteria plumonalis and the pulmonary capillary pressure and, if necessary, the Herx time volume is determined and the other diagnostic results derived from this Values are determined.

These measured values are saved as much as possible for the test person received without significant interference and thus open up a further diagnostic Area.

L e r s e i t e

Claims (14)

P A T E N T A N S P R Ü C H E (1.l r.an7knrpernlethysmogranh, consisting from a chamber enclosing the test person in an airtight manner, one inside the chamber on the @robanden connected breathing tube with Pneumotschogrph and a Kammerwandpneumotachoqraphen for measuring the chamber pressure or volume eoderunpen as well as connected to a calculator Measuring devices for individual values of the pulmonary fundation test, d a d ti r c h n e k e n It is noted that the chamber (1) serves to stabilize the prevailing inside the chamber Climatic conditions a ventilation device (16,17) and means (18,37,38) for heat and humidity control. 2. Whole body plethysmograph according to claim 1 d a d u r c h g e k e n n z e i c h n e t that the ventilation device (16, 17) from an air inlet opening (11) and an exhaust air line (15) with a control valve (17) and an exhaust fan (16) exists. 3, whole-body plethysmograph according to claim 2, d a d u r c h n e k e n n z e 1 c h n e t that the control valve (17) essentially consists of a nozzle. 4. Whole-body plethysmograph according to claim 3, d a d u r c h g e k e Note that the nozzle is in the form of a Lafval nozzle. 5. Whole-body plethysmograph according to one of claims 1-4, d a d u r c h g e k e n n n n e i c h n e t that within the chamber (1) a known per se Ergometer device (7) is arranged. 6. Whole body plethysmograph according to any one of claims 1-5, d a d u r c h g e k e n n n n z e i c h n e t that the chamber (1) consists of a base (2) and an airtight hood (4) which can be fastened thereon and which is designed so that the chamber (1) has a minimum volume. 7. Whole body plethysmograph according to claim 6, d a d u r c h g e k e It is noted that the hood (4) is in the area of the legs and upper body of the recumbent subject (20) essentially semi-elliptical (8) and in the head and neck and shoulder area substantially semicircular (9) cross-sections with continuous Has transition. 8. Whole body plethysmograph according to claim 6 or 7, d a d u r c h It is noted that the hood (4) is made of transparent plastic. 9. Whole-body plethysmograph according to one of claims 6-8, d a d u r c h e k e n n n z e i c h n e t that the base (2) is at 90 ° transversely to its Is arranged to be pivotable in the longitudinal direction about a horizontal axis (3). 10. Whole body plethysmograph according to one of claims 6 to 9, d a it is indicated that the cover layer (2) is made of thermally highly conductive Material. 11. Whole body plethysmograph according to claim 10, d a d u r c h g e k It is noted that between the base (2) and the support surface (6) Heat dissipation fins made of thermally highly conductive material are arranged. 12. Whole body plethysmograph according to one of claims 1 to 11, d a d u r c h g e k e n n n z e i c h n e t that in the chamber (1) a device (18) is arranged to achieve a transverse or swirl flow. 13. Whole body plethysmograph make claim 12, d a d u r c h g 8 k It is noted that the device (18) for generating a transverse or swirl flow of several attached to the long side of the chamber (1) and transversely to the longitudinal axis of the chamber directed circulating air fans (18). 14. Whole body plethysmograph according to one of claims 6 to 13, d a d u r c h g e k e n n n z e i c h n e t that the hood (4) above a toggle locking mechanism (5) is pivotably connected to the base (2). 75, whole body plethysmigr according to one of claims 1 - 14, d a d u Noted that inside and outside the chamber (1) Iemparaturmeßschleifen (37, 38) to determine the thermal drift and the corresponding correction factors are arranged.