CS219151B1 - Rule for calculation of the right-and left hand faults - Google Patents

Description

(54) Ruler for the calculation of right-to-left shorts

The invention relates to a ruler for the calculation of right-to-right shunts of blood circulation by determining both intracardiac and extracardiac right-to-right shunts.

The current method of determining right-to-left shunts is to analyze blood gases in arterial and mixed venous blood by breathing air and high oxygen concentrations and hemoglobin concentration. From these data, the total and anatomic right-left shunt are calculated using short-circuit equations and a functional right-left shunt is obtained from the difference of these values.

The drawbacks and barriers to using these valuable indicators in routine medical practice are that calculating the anatomical right-hand short circuit requires knowing the exact value of the oxygen tension in the blood when breathing high oxygen concentrations (hyperoxic blood). Determining this value is subject to up to 20% of methodological error, which significantly reduces the diagnostic power of this indicator. The most important source of this methodological error is the decrease in oxygen tension resulting from blood collection and storage until the time of analysis. Further, right-sided cardiac catheterization is required to obtain baseline blood gas values from mixed venous blood, as required by a specialized clinic. In order to simplify this part of the examination, standard arterio-venous oxygen differences are often used. Many of the recommended values are only estimates, they are obtained from a heterogeneous group of investigators and the calculated shortcuts are therefore inaccurate. From the measured values of blood gases, short-circuits are calculated using desktop or pocket calculators. This procedure is cumbersome and vulnerable. Faster programmable computers are not standard equipment in clinical workplaces. To simplify the calculation, various nomograms are also used, which, although they allow the result to be read quickly ', do not include several important input data and are therefore inaccurate.

These obstacles cause the right-to-left short-circuits to be the domain of highly specialized clinical and research workplaces and have little use in normal medical practice.

The above drawbacks are overcome by the right-to-right short circuit calculation according to the invention, which is based on a double-skinned sliding ruler with one small and one true sliding tongue and one slider. One side of the double skin is provided with three cut-outs and a scale for barometric pressure against which there is a scale for blood carbon dioxide pressure on the large sliding tongue and a scale for alveolar oxygen tension which combines with the exponential scale of alveolar oxygen tension created on the scale. the tongue, which is scaled by the scale of different hemoglobin concentrations in the blood on the runner, above which the scale of oxygen concentration in the blood and below the small cut-out is on the small sliding tongue, the scale for total right-to-right shunt created on the runner. On the other side of the shell there are three slits and four scales, where at the top slice there is a scale for barometric pressure corresponding to the scale of carbon dioxide tension in hyperoxic blood formed on the large sliding tongue and scale for alveolar oxygen tension during oxygen breathing and reciprocally for corrective oxygen tension in hyperoxic blood, in the middle of the mantle there is a scale of measured carbon dioxide tension in hyperoxic blood communicating with scales of correction factors for errors caused by blood storage on the runner, with a large cut-out showing a scale for anatomical right-hand scale for different concentrations of arterio-venous oxygen difference on the runner, while at the bottom notch there is a common scale for total and functional right-to-right short-circuiting communicating with the scale for anatomical right-to-right short-circuit small sliding tongue.

By using the ruler to calculate the right-hand short circuits according to the invention compared to the method used hitherto, the calculated values of the anatomical right-hand shorts are substantially refined due to the two correction systems used in the ruler. The correction for the error caused by the collection of hyperoxic blood is solved by correlation of scaling for measured and corrected oxygen tension values in hyperoxic blood. Error correction due to blood sample storage at 0 ° C and 24 ° C is performed using two scales per runner. The above corrections almost completely eliminate up to 20% of the methodological error of the original investigation procedure.

Use of a constant arterio-venous oxygen difference of 1.71 mmol. I- ¹ , empirically determined on an 84-member group of patients, eliminates the need for cardiac catheterization in subjects without severe haemodynamic disorders when tested in the body. At the same time, the gilthead allows the calculation of short-circuits from values obtained by cardiac catheterization for those cases where the nature of the patient's clinical condition so requires.

By using a ruler to calculate right-handed scraps according to the invention, the time required is substantially reduced. ‘To calculate all short-circuits and limit the possibility of errors while maintaining the required accuracy for Minic practice. Compared to the use of nomograms, the results are more accurate as they take into account all the relevant measured data needed to calculate the short-circuits.

The accompanying drawings show an overall view of a ruler for calculating right-hand short-circuits from both sides, where FIG. 1 shows scales for barometric pressure, blood carbon dioxide tension, oxygen tension in alveolar air, blood hemoglobin concentration, blood oxygen concentration, as well as the resulting values of total right-to-right shunt at different arterio-vertical oxygen difference values and the runner so an arrow that intersects all the scales. In FIG. Table 2 shows scales for barometric pressure, carbon dioxide pressure in hyperoxic blood, oxygen pressure in alveolar air during oxygen breathing, measured and corrected oxygen pressure in hyperoxic blood, correction factors for error correction caused by hyperoxic blood storage and resulting anatomical right values. left arrow at different arterio-venous oxygen difference values, as well as an arrow on the runner that crosses the scale of the anatomical short and measured oxygen tension values in hyperoxic blood, with scales for overall, functional and anatomical short at the bottom of this figure.

The ruler for calculating the right-hand short-circuits according to the invention consists of a double shell X with one large sliding tongue Z, one small sliding tongue Y and one slider U. On one side of the shell (Fig. 1) is a linear scale I expressing barometric pressure. corresponds to a linear scale II expressing the blood pressure of carbon dioxide and which is located on the small sliding tongue of the ruler Y. The ratio of the linear scale I to the scale II is 1: 5.2. The scale II corresponds to the linear scale III for the alveolar oxygen tension on the shell of the ruler X. The ratio of the scale division Π to scale III is 1: 0.8776. The scale ΙΠ corresponds to the non-linear scale IV for the alveolar oxygen tension, located on the large sliding tongue Z of the ruler. From the IV scale there are lines of the same alveolar oxygen tension value, called isoplets, pointing to the VI scale on the large sliding tongue Z, which expresses the oxygen correction in the blood. The ratio of IV scale division to VI scale division is obtained empirically and follows the hemoglobin dissociation curve. The scale V formed on the runner U indicates hemoglobin values and crosses the isoplates running between scales IV and VI. The scale VII on the small sliding tongue Y of the ruler expresses the total right-to-right short-circuit and is represented by fan-shaped lines of the same short-circuit values. Scale VIII on runner U indicates arterio-venous oxygen difference values and crosses scale VII. The ratio of the scale division VI to the scale division VH is governed by the equation:

C (c'-a) O ₂ - <= ( _a -v) O ₂ . Qs / Qt (t) ^V '100 - Qs / Qt (t) wherein C (c'-a) O ₂ . . . . is the difference in oxygen concentrations between end capillary and arterial blood,

C (a-V) O ₂ .... is the difference resulting in oxygen friction between arterial and mixed venous blood,

Qs / Qt (t) .... is the total right-to-left short circuit.

On the U runner there is an arrow that crosses all scales perpendicularly and serves to transmit data from one scale to the other.

On the other side of the ruler shown in FIG. 2, there is a barometric pressure scale 1 on the housing X, which corresponds to a scale 2 for the carbon dioxide pressure during oxygen breathing, applied to the large slide tongue Z of the ruler. The arrow on the scale 2 corresponds to the scale 3 on the ruler shell X, which simultaneously represents the alveolar oxygen tension as well as the corrected oxygen tension value in the blood during oxygen breathing. Scales 1, 2 and 3 are linear and have the same division. The linear scale 4 on the ruler shell X indicates the measured oxygen tension values of the blood when breathing oxygen. The ratio of scale division 3 to linear scale 4 is governed by:

PaO ₂ (cor.) (O ₂ ) = PaO ₂ (mer) (O ₂ ). 1.033376 + + 0.67519 where: PaO ₂ (cor.) (O ₂ ) ... is the corrected value of the oxygen tension in the blood when breathing oxygen, and

PaO ₂ (Mer) (O ₂ ). . . is the measured oxygen tension in the blood during oxygen breathing.

The linear scale 4 corresponds to the scales 5 and 6, which are applied to the runner U and which express correction factors for a methodological error caused by blood storage at 0 ° C and at 24 ° C. On the runner U there is an arrow going perpendicular to the scale 4, with the scale 5 and 6 crossing at their 0 value. The scale 7 on the large sliding tongue Z indicates an anatomical right-to-left short-circuit and is represented by fan-shaped lines of equal short-circuit values - isoplates. Scale 8 on runner U expresses arterio-venous oxygen difference and crosses scale 7. The relationship between scales 3 and 7 is expressed by the equation:

P (A - a) O ₂ (O ₂ ) =

C (i-v) The _second Qs / Qt (a) 1.04 - 0.014. Qs / Qt (a) where: P (A — a) O ₂ (O2) · · · is the alveolo-arterial oxygen difference when breathing oxygen,

C (a-v) O ₂ ..... is the difference in oxygen concentrations between arterial and mixed venous blood, and

Qs / Qt (a) ..... is an anatomical right-to-left short circuit.

The scale A on shell X expresses the value of the total right-to-right short circuit and at the same time the functional right-to-right short circuit. The scale B on the small sliding tongue Y of the ruler expresses the values of the anatomical right-to-left short circuit. The scales A, B are linear and have the same division.

Examples of using a ruler according to the invention are given below without limiting the use of the ruler:

Example 1

When a scale of 5 or 6 correction factors for 0 ° C or 24 ° C per runner U is set according to the current temperature and storage time of the blood sample to the measured oxygen tension value in hyperoxic blood according to linear scale 4, the arrow on runner U corresponds to the measured the oxygen tension value of the hyperoxic blood sample at the time of sampling according to the linear scale division 4, the oxygen tension value of the hyperoxic blood corrected for the error resulting from the blood sampling according to the scale division 3 and the resulting value of the anatomical right shunt on result scale 7.

Example 2

In subjects without significant hemodynamic disturbances and physical room arrow The slide ruler gives the value of the total, or anatomical right-IAVE short circuit scale Jul 7 falls on the scale at a constant value of 1.71 mM scale ¹ VIII, respectively. 8 for arterio-venous differential without the need to use values obtained by right-sided cardiac catheterization.

The invention allows for a quick and simple calculation of total, anatomical and functional right-to-right shunt, at the same time allows for correction of collection and storage of hyperoxic blood, and allows for short-term cardiac catheterization in persons without severe haemodynamic disturbances. In addition, the ruler makes it possible to calculate the blood oxygen concentration and the alveolar tension of oxygen when breathing air and medical oxygen.

The invention finds application in internal medicine, in pneumology, in cardiology, in anesthesia, in thoraco- and cardiosurgery and in laboratories for functional cardiopulmonary diagnostics.

Claims (1)

OBJECT OF THE INVENTION Ruler for the calculation of right-hand short-circuits, characterized in that one side of the double skin (X) is provided with three cut-outs and on the other hand with a barometric pressure scale (I) against which a large sliding tongue (Z) has a blood carbon dioxide pressure scale ( II), on the other hand, a scale for alveolar oxygen tension (III) that communicates exponentially _{with a} scale of alveolar oxygen tension (IV) formed on a large sliding tongue (Z) which is intersected by a scale of different concentrations! of hemoglobin in blood (V) on a runner (U) above which is a scale of oxygen concentration in blood (VI) and above the small cut-out is on a small sliding tongue (Y) scale for total right-to-left shunt (VII) For the different values of arterio-venous oxygen difference (VIII) formed on the runner (U) and on the other side of the shell (X), three cut-outs and four scales are formed, where the upper cut-out is a scale for barometric pressure (1). a scale of carbon dioxide tension in hyperoxic blood (2) formed by a large sliding tongue (Z) and a scale for alveolar oxygen tension during oxygen breathing and reciprocally for corrected tension _{t of} oxygen in hyperoxic blood (3), in the middle of mantle f ( X) is a scale of measured oxygen tension in hyperoxic blood (4) communicating with a scale of correction factors for custody errors (5, 6) generated on the runner (U), with a large cut-out The scale on the large sliding tongue (Z) is the scale for anatomical right-to-left shunt (7) and above it on the runner (U) is the scale for the different values of arterio-venous oxygen difference (8). and a functional right-to-left short circuit (A) communicating with a scale for anatomical right-to-right short circuit (B) formed on a small sliding tongue; s