DE3842899A1 - Rhinomanometer with performance plots - Google Patents

Abstract

In nasal function tests and allergology, the transnasal pressure DELTA p and the volume flow V during breathing are measured. It is demonstrated that information is lost on presentation of the measured results in the form of a rhinomanogram. It is proposed that the measurements be used to calculate the performance on nasal breathing and the mean volume flow of one breath. With a variable depth of inspiration, the breathing performance can thus be represented as a function of the air requirement. For this task it is only necessary to change the software of existing rhinomanometers.

Description

The present invention relates to a rhinomanometer according to claims 1 and 2.

1 Introduction

In rhinomanometry there is pressureΔ p and volume flow  of the nasal air flow. The Measured values are put together to form a rhinomanogram, in which as a parameter  at 75, 150 and 300 Pa can be read (1, 2). This procedure complies with international standards, but has the Disadvantage that a lot of information is lost like temporal behavior of breathing. Furthermore, sizes basically become measured and presented for breathing from are of secondary importance. More important than Momentary values like ₁₅₀, sizes appear like that mean volume flow when breathing, the Characterized human air consumption, and the power()that is necessary for breathing. It it is shown that even with these sizes and   rhinomanometry can be done. It also works the temporal behavior of the breathing curves. For the Only the software of the existing software has to be used Rhinomanometer to be changed.

2. Work and performance power

When breathing, a power (in watts) must be applied to let the air flow through the nose. This can be calculated from the work, whose change d W is given by

d W = Δ p d V , (1)

where Δ p is the transnasal pressure and d V is the volume element that flows through the nose. The definition of performance is

where the volume flow  by  = dV/ dt Are defined is. Equation (3) makes it clear how the current one Performance can be determined. It is afterpicture 1 the area of the rectangle (Δ p ·)which by the Point (Δ p,) is defined on the measurement curve. It is understandable that performance during a Breathing curve fluctuates greatly.

As an example, the current performance of the nasal breathingΔ p = 150 Pa of a normal one People with ₁₅₀ = 0.7 l / s are given:

P = 150 Pa 0.0007 m³ / s = 0.1 W. (4)

From the rhinomanogram the momentary value of the Performance, but not the average performance, be determined. The information is in this Presentation has been lost. It should be noted that the specified power relates only to the air flow in the nose. The actual Breathing performance is higher because the lungs are breathing is involved, and the respiratory muscles one Efficiency less than 100%.

job

The work or energy expended on breathing can be done by integrating equation (1) can be determined:

Nor can the work come from the rhinomanogram be determined. However, it can be from the breathing curves (t) andΔ p (t) depending on the time after picture 2 can be calculated numerically. You shape it Equation (5) with dV =  dt around

You have to gopicture 1 in regular intervals IntervalsΔ p and  read, multiply and sum up. The calculation is for a computer program fromW easy.  

Medium performance

The average performance is important when breathing. One can take the mean over a breath of period T.

Of course, the average breathing power depends on the air consumption, ie the average volume flow V. Before going into this, the equations should be simplified. It should be assumed that p and V are quadratic

Δ p =w   ². (8th)

The coefficient w can be expressed by V ₁₅₀: w = 150 Pa / V ₁₅₀². Equation 8 gives the instantaneous power

P =w   ³ (3a)

Applies to work

and for medium performance

It can be seen that the time behavior of the measured variables V (t) (and p (t)) , which has been lost in rhinomanograms, is important for determining W and P. With the simplified assumption of a "rectangular" and "triangular" volume flow V (t) according to Figure 3, one obtains by simply integrating equations (8), (6a) and (7a):
"rectangular" breath curve

"triangular" breath curve

Both model cases have identical rhinomanograms featured. The mean respiratory rate is different, however, because of the temporal behavior breathing is different. It's understandable, that the average power from the air consumption d. H. of the mean volume flow when breathing must depend. This is defined as the mean e.g. B. over one breath

This value gives the real air consumption of the People breathing, at ₁₅₀ not the case is. An arithmetic program canpicture 2a relative just determine.

3. Nasal performance curve

It is suggested in addition to the rhinomanogram also the performance curve of the nasal respiratory flow measure up. To do this, use a rhinomanometer (with Microprocessor or computer) breathing variable depthpicture 4 measured. For each breath is the mean by the computer power  and the mean volume flow determined. To include hysteresis should only for a quarter of a period to get integrated. In the equations for  and so canT byT/ 4 to be replaced.

For medium performance  and the middle one Volume flow is shown after picture 5. One expects one according to equation (9) context

Existing rhinomanometers are proposed to program, and the predictions too check. You get additional information at different breathing depths.

If you measure with the posterior method, you can the power curve for both sides of the nose measure together or individually.  

Unfortunately, this procedure is common to many subjects because of the reflex movements of the palate not applicable.

With anterior rhinomanometry, only anyone can Nose side to be measured individually. This is in the Representation of the rhinomanograms is not a problem since the total curve by adding the individual curves can be manufactured. With the performance curves is this is more complicated, however, can be caused by a Calculator the performance curve of the two Nose sides are constructed. You can do that Δ p-Measurement curve on the other side of the nose lay. With the help of the total rhinomanogram the Curve determined for both sides of the nose. With These intermediate results are described Evaluation to determine the performance curve carried out.

4. Discussion

The proposed procedure evaluates the rhinomanometric measurements different than before out. This makes new information clear visualized graphically. An illustration of the power  in nasal breathing depending on the medium volume flow  in form of a Performance curve afterpicture 5 seems reasonable. Also here can be a characteristic value  with normal air requirement (e.g. = 1 l / s) can be specified.  

Literature:

(1) Bachmann, W .: The functional diagnosis of disabled nasal breathing, Springer-Verlag, Heidelberg, 1982
(2) Eichler, J .: Introduction to the technique of rhinomanometry, Quintessenz-Verlag, Berlin, 1986

picture 1: The current performanceP =Δ p   is the Area of the hatched rectangle (e.g. P₁₅₀ = 150 Pa ₁₅₀.
picture 2: To calculate the work in nasal Breathing will occur at regular intervals  andΔ p multiplied and summed up.
picture 3:
a.) Model of a "rectangular breath curve".
b.) Model of a "triangular breath curve".
picture 4: Breaths to measure the performance curve topicture 5.
picture 5: performance curve of nasal breathing, average power depending of the mean volume flow.

Claims (2)

1. Rhinomanometer with an arrangement for measuring the air flow (volume flow V) through the nose and the transnasal pressure p , characterized in that the instantaneous nasal breathing performance is calculated from the above measured variables by an electronic circuit (e.g. microcomputer), that mean values the breathing performance are calculated, that mean values of the volume flow are calculated, that the above-mentioned variables are output graphically. 2. Rhinomanometer according to claim 1, characterized, that in a coordinate system the mean values of respiratory performance depending on the corresponding mean values of the volume flow are shown.