RU2770282C1 - Method for diagnosing the variant of cold hyperreactivity of the respiratory passages in patients with bronchial asthma - Google Patents

Abstract

FIELD: medicine.

SUBSTANCE: invention relates to medicine, namely to pulmonology, and can be used to diagnose a variant of cold hyperreactivity of the respiratory passages in patients with bronchial asthma. To do this, in patients with bronchial asthma with cold hyperreactivity of the respiratory passages, cortisol levels in venous blood are examined, a bronchoprovocation test with isocapnic hyperventilation with cold air is performed. Next, the change in the volume of forced exhalation in 1 second (ΔVFE1) and the instantaneous volume velocity of forced exhalation at the level of 50% of the forced vital capacity of the lungs (ΔIVV50) after a sample of isocapnic hyperventilation with cold air is calculated as % of the initial values. Then the value of the discriminant function D is calculated using the developed equation with the boundary value of the discriminant function equal to -61.12. When the value of D is equal to or greater than the boundary value of the discriminant function, a permanent variant of cold airway hyperreactivity is diagnosed in a patient with bronchial asthma; when the value of D is less than the boundary value of the discriminant function, a fluctuating variant of cold airway hyperreactivity is diagnosed in a patient with bronchial asthma.

EFFECT: invention makes it possible to diagnose a permanent or fluctuating variant of cold hyperreactivity of the respiratory tract in this category of patients with a single diagnostic test.

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Description

A known method for diagnosing a variant of nonspecific hyperreactivity of the respiratory tract, allowing to distinguish between its permanent and fluctuating variants [1]. The known method consists in measuring the response of the bronchi to inhalation of a 0.1% solution of acetylcholine chloride monthly for a year or more. With an increase in bronchial resistance, measured by body plethysmography, by more than 25% of the original after inhalation, or with a decrease in forced expiratory volume in 1 sec. by 15% or more in all measurements, a permanent variant of nonspecific airway hyperreactivity is diagnosed. In the absence during one or more measurements of data on changes in bronchial resistance or forced expiratory volume in 1 sec. diagnosing fluctuating airway hyperreactivity.

The known method has the following disadvantages:

1. Inability to assess cold airway hyperresponsiveness by means of an inhalation test with a solution of acetylcholine chloride.

2. The duration of the diagnostics, associated with the need for measurements for a year or more.

3. The need for multiple visits to the clinic for the purpose of monthly body plethysmography, forced expiratory spirometry and determination of the response of airway smooth muscles to a bronchoprovocation stimulus to diagnose a variant of nonspecific airway hyperreactivity.

4. The duration of each diagnostic testing procedure, which leads to patient fatigue and distortion of the results.

5. The presence of a number of restrictions for conducting a bronchoprovocation test during multiple visits, including the registration at the time of testing of a violation of the ventilation function of the lungs of an obstructive type with a decrease in forced expiratory volume in 1 second. below 70% of the due value, the addition of an acute respiratory viral infection, the appearance of allergies, etc. [2, 3].

6. The probability of false-negative results in patients with impaired lung ventilation function of the obstructive type at the time of the bronchoprovocation test, since the bronchial obstruction existing at that time can neutralize the reaction of the smooth muscles of the respiratory tract to the bronchoprovocation stimulus.

The aim of the invention is to provide the possibility of diagnosing a permanent or fluctuating variant of cold airway hyperreactivity in patients with bronchial asthma with a single diagnostic test.

The goal is achieved by the fact that the diagnosis of the variant of cold airway hyperreactivity in patients with bronchial asthma is carried out by assessing the reaction of the airways to the bronchoprovocation test of isocapnic cold air hyperventilation (IHC) and the study of the basic content of cortisol in the blood serum (nmol/l). Then, using a discriminant equation that includes a change in spirometric parameters (forced expiratory volume in the first second, instantaneous forced expiratory volumetric velocity at the level of 50% of the forced vital capacity of the lungs) in response to the HCI test and the content of cortisol in the blood serum, a constant or fluctuating type of cold is diagnosed. hyperreactivity of the respiratory tract in patients with bronchial asthma.

The essence of the method consists in determining the discriminant function (D) in patients with mild and moderate bronchial asthma with cold airway hyperreactivity, in relation to which, in relation to the boundary value of the discriminant function, permanent or fluctuating variants of cold airway hyperreactivity are diagnosed.

The method contains the following steps:

1. In a patient with bronchial asthma in the morning, blood is taken from a peripheral vein (cubital).

2. Determine the content of cortisol in the blood serum (nmol / l), for example, by enzyme-linked immunosorbent assay (ELISA, "sandwich" method) using sets of specific reagents.

3. Using the method of spirometry, the forced expiratory volume in the first second (in l) is determined.

4. Using the spirometry method, the instantaneous volumetric forced expiratory flow rate is determined at the level of 50% of the forced vital capacity of the lungs (in l / s).

5. A bronchoprovocation test is performed for 3 minutes with cold air cooled to -20°C containing 5% CO2 [4].

6. Calculate the change in forced expiratory volume in 1 second. as a percentage of the original (ΔFEV1).

7. Calculate the magnitude of the change in the instantaneous forced expiratory volumetric velocity at the level of 50% of the forced vital capacity as a percentage of the original (ΔMOS50).

8. Determine the value of the discriminant function D using the discriminant equation

D = -2.146 x ΔFEV1 + 0.860 x ΔMOS50 - 0.118 x Cortisol,

where D is a discriminant function with a boundary value equal to -61.12.

9. Compare the value of the discriminant function with its boundary value equal to -61.12. When D is equal to or greater than the boundary value of the discriminant function in a patient with bronchial asthma, a permanent variant of cold airway hyperreactivity is diagnosed; when D is less than the boundary value of the discriminant function, a fluctuating variant of cold airway hyperreactivity is diagnosed.

The effectiveness of the proposed method in clinical practice is illustrated by the following examples.

Example 1: Patient K., 45 years old. Clinical diagnosis: Bronchial asthma, mixed form, moderate severity, partially controlled course, DN0. Cold airway hyperreactivity.

Observed by a pulmonologist at the Far East Scientific Center for Physiology and Pathology of Respiration (DSC FPD).

From the anamnesis: suffering from bronchial asthma for 7 years; notes the appearance in the last 2 years of respiratory discomfort, an increase in shortness of breath and an increase in the frequency of use of short-acting β2-agonists during the onset of cold weather (negative air temperatures)

She complained of the development of suffocation upon contact with cold air.

The patient was referred by a pulmonologist to the Department of Functional Diagnostics of the DSC FPD for the purpose of conducting a bronchoprovocation IHCI test to determine further therapy tactics.

Before the IHCI test in the treatment room, the patient underwent blood sampling from the cubital vein to determine the cortisol content.

A standard bronchoprovocation test of isocapnic hyperventilation with cold air (3 minutes, -20°C) was performed. After the test, a decrease in FEV1 by 16.0%, MOS50 by 24.0% (positive test) was registered, which confirms the presence of cold airway hyperreactivity in the patient.

The content of cortisol in the blood serum - 601.0 nmol / l.

Next, the discriminant equation was solved:

D \u003d -2.146 × (-16.0) + 0.860 × (-26.0) - 0.118 × 601,

where D is a discriminant function, the boundary value of which is equal to -61.12.

Since the value of D obtained by solving the discriminant equation (-58.942) is greater than the boundary value, the patient was diagnosed with a permanent variant of cold airway hyperreactivity.

Subsequently, when visiting a pulmonologist every 6 months in order to monitor the disease in dynamics and correct the prescribed therapy for several years, a decrease in FEV1 by 13.0% was recorded in the patient during the IHCI test; 53.2%; 45.0%; 16.4%; 18.2, 18.0%; 22.0%, which indicates the presence of a permanent variant of cold airway hyperreactivity.

Example 2: Patient B., aged 48, Clinical diagnosis: Bronchial asthma, mixed form, moderate severity, partially controlled course of DN0. Cold airway hyperreactivity.

Observed by a pulmonologist at DSC FPD.

From the anamnesis: suffering from bronchial asthma for 9 years; in the last 3 years, he has noted an increase in shortness of breath and an increase in the frequency of using short-acting β2-agonists in the cold season (negative air temperatures).

She complained of the development of suffocation upon contact with cold air.

The patient was referred by a pulmonologist to the Department of Functional Diagnostics for a bronchoprovocation IHCI test and to determine further therapy tactics.

Before the IHCI test in the treatment room, the patient underwent blood sampling from the cubital vein to determine the cortisol content.

A standard bronchoprovocation test of isocapnic hyperventilation with cold air (3 minutes, -20°C) was performed. After the test, a decrease in FEV1 by 15.0%, MOC50 by 27% (positive test) was registered, which confirms the presence of cold airway hyperreactivity in the patient.

The content of cortisol in the blood serum - 607.0 nmol / l.

Next, the discriminant equation was solved:

D = -2.146 × (-15.0) + 0.860 × (-27.0) - 0.118 × 607.0,

where D is a discriminant function, the boundary value of which is equal to -61.12.

Since the value of D obtained by solving the discriminant equation (-62.656) is less than the boundary value, the patient was diagnosed with a fluctuating variant of cold airway hyperreactivity.

In the future, when visiting a pulmonologist to monitor the disease in dynamics (1 time per year) for several years, a fall in FEV1 by 11.0% 3.8% was recorded in the patient during the IHCV test; 12.7%; 18.0%; 4.2%, that is, there was a fluctuating variant of cold airway hyperreactivity.

The inventive method was tested in 68 clinical cases in patients with bronchial asthma with cold airway hyperreactivity.

Based on the observation of this category of patients, the sensitivity, specificity, and accuracy of diagnosis [5] of a constant or fluctuating variant of cold airway hyperreactivity in patients with bronchial asthma were calculated.

Sensitivity (in %) was defined as the ratio of true positive diagnostic results (30 observations) to the sum of true positive (30 observations) and false negative results (4 observations). The sensitivity index was 88.2%.

Specificity (in %) was calculated as the ratio of true negative diagnostic results (28 observations) to the sum of true negatives (28 observations) and false positives (6 observations). The specificity index was 82.4%.

Accuracy (in %) was calculated as the ratio of all correct diagnostic results, i.e. the sum of true positive (30 observations) and true negative (28 observations) diagnostic results to the total number of diagnoses (i.e., to the total number of patients). The diagnostic accuracy was 85.3%.

The technical result of the invention is as follows. The claimed method makes it possible to diagnose a certain variant (permanent or fluctuating) of cold airway hyperreactivity in patients with bronchial asthma.

Used information sources:

1. Perelman Yu.M., Prilipko N.S. Hyperreactivity of the respiratory tract in chronic bronchitis // Bulletin of Physiology and Pathology of Respiration. 1998. Issue 1. pp.28-34.

2. Sterk P.J. , Fabbri L.M., Quanjer Ph.H., Cockcroft D.W., O´Byrne P.M., Anderson S.D., Juniper E.F., Malo J-L. Airway responsiveness // Eur. Respir J. 1993. Vol. 6, #16. P. 53-83. doi:10.1183/09041950.053s1693

3. Borak J., Lefkowitz R.Y. Bronchial hyperresponsiveness // Occup. Med. (Lond). 2016. Vol. 66, no. 2. P. 95-105. doi:10.1093/occmed/kqv158

4. Perelman Yu.M., Prikhodko A.G. Diagnosis of cold airway hyperreactivity: Guidelines. Blagoveshchensk, 1998. 8 p.

5. Karmazanovsky G.G. Assessment of the diagnostic significance of the method (“sensitivity”, “specificity”, “general accuracy”) // Annals of Surgical Hepatology. 1997. No. 2. pp. 139-142.

Claims (3)

A method for diagnosing a variant of cold airway hyperreactivity in patients with bronchial asthma, characterized in that the level of cortisol in venous blood is determined in nmol/l, as well as changes in forced expiratory volume in 1 second (ΔFEV1) and instantaneous volumetric forced expiratory flow rate at the level of 50% forced lung capacity (ΔMOC50) after a test of isocapnic hyperventilation with cold air in % of the initial values, then diagnostics are carried out by comparing the value of the discriminant function D, calculated using the discriminant equation D = -2.146 x ΔFEV1 + 0.860 x ΔMOS50 - 0.118 x Cortisol, with the boundary value of the discriminant function equal to -61.12; when D is equal to or greater than the boundary value of the discriminant function, a permanent variant of cold airway hyperreactivity is diagnosed in a patient with bronchial asthma; when D is less than the boundary value of the discriminant function, a fluctuating variant of cold airway hyperreactivity is diagnosed in a patient with bronchial asthma.