Acoustic assessment of pulmonary ventilation in children with bronchial asthma on the background of a single exposure to microwave radiation

Full Text

INTRODUCTION

Heterogeneity of broncho-obstructive syndrome (BOS) is a subject of considerable practical interest for pediatricians, allergists, and pulmonologists. Over the past 10 years, the understanding of the details of the pathogenesis of respiratory tract obstruction syndrome has been significantly expanded [2, 8]. However, there is no doubt that to objectively assess clinical states in diseases accompanied by BOS, additional criteria must be taken into account, such as the reaction of the bronchial tree in response to therapeutic effects. Regarding the selection of complex treatment methods, a combination of basic and alternative therapy for bronchial obstruction is currently being considered [7]. Previous studies have shown positive results of using non-thermal microwave radiation for prolonged coughing and respiratory diseases with bronchial obstruction syndrome [3]. The efficiency of the unit “Aster” on bronchial asthma (BA) was examined for a long time by a course from 8 to 14 treatments. It revealed no clear bronchodilator effect in one case, but in another case, it tended to increase the indicators of bronchial obstruction, decrease the frequency of β2-agonists administration with a quick regression of day and night symptoms of the disease [10].

The results obtained are contradictory and no clear data explains the mechanism of exposure to the respiratory tract and the possibility and rationale of using ultra-weak electromagnetic waves in patients of different age groups with different severity of BA [12, 13].

This study aims to conduct an acoustic assessment of the functional state of the bronchopulmonary system of children with BA of various severities after single microwave exposure.

MATERIALS AND METHODS

Acoustic parameters were evaluated for a single exposure to the Aster unit in the “pre-experiment” mode (without randomization, the initial data were used as a control) [14]. Taking into account the conflicting data on the influence of electromagnetic radiation in bronchopulmonary diseases, a single application of non-thermal electromagnetic radiation was done to clarify the nature of changes in pulmonary ventilation.

The main group was initially made of 122 patients with BA, aged from 3 to 17 years who gave informed voluntary consent to participate in the study. The exclusion criterion was the presence of chronic diseases in the acute stage and acute infectious diseases. The initial parameters of patients were used as control data.

The diagnosis of BA was made per the diagnostic criteria of the consent documents [6]. Nine patients (7%) had virus-induced exacerbations of BA (BOS more than three times in the last year after acute respiratory viral infection and a burdened allergic history). Patients with virus-induced exacerbations received leukotriene receptor antagonists (montelukast) as basic therapy and were subsequently excluded from the study. In the main group of subjects, the allergic phenotype of asthma prevailed: 113 (93%) patients had increased immunoglobulin E (IgE) levels and peripheral blood eosinophilia. These patients were divided according to the severity of BA as follows: mild BA – 33 (29.2%), moderate asthma – 36 (31.9%), and severe BA – 44 (38.9%). At the time of hospitalization in the department of pulmonology of the Regional Children Clinical Hospital of Chita, patients were in a period of acute asthma. The assessment of acoustic parameters was carried out between the 5^th and 7^th day of relief from an acute attack, which did not exclude the presence of hidden bronchospasm.

All patients of the main group (113 people) were given a session of non-thermal electromagnetic radiation using the Aster unit¹ [5]. The duration of the session was 7 minutes following instructions: The examination was done in a separate room without extraneous noise. The time for a re-evaluation of bronchial patency was chosen empirically, taking into account the subjective feeling of a breathing relief of patients. The respiratory cycles were recorded at the following time points: T₀ – the initial measurement, T₁ – after 5 minutes, and T₂ – 15 minutes after the Aster session. Patients received therapy with the Aster device. Broncholytic drugs were excluded for 7–8 hours before the study and, thus, could not affect bronchial patency.

Improvement of bronchial patency indicators was chosen as the endpoint of the study when using the Aster device. The result at the endpoint of the study was classified as “there is an outcome/no outcome.” The result of exposure to electromagnetic radiation on bronchial patency was evaluated using the computer bronchophonography unit “Pattern 01.” To assess the intensity of the acoustic phenomenon of breathing, the K₂ coefficient was used (a relative value reflecting the ratio of data on the acoustic work of breathing in the high-frequency range to the acoustic work in the low-frequency range of the bronchophonogram). The K₂ coefficient characterizes the acoustic work of respiration performed by the respiratory system to promote air at the level of the bronchi of a medium and small caliber [2–4, 11]. An increase in K₂ indicates the presence of obstructive disorders.

Next, to assess the dynamics of clinical symptoms, a group of A – 20 (17.7%) patients (average age is 6.5 years (4.0–9.0)) was randomly selected. They received a traditional basic therapy in combination with microwave therapy sessions for 7 days, twice a day. A comparison group–group B was randomly selected and matched for gender and age with group A. It included 12 patients (10.6%) with BA who received only traditional basic therapy.

Statistical processing of the results was performed using the program Statistica Stat Soft 10.0. Quantitative values were presented as median (Me 25–75 percentile) and relative (%) values. Statistical significance between unrelated groups was determined using the Mann–Whitney test, and between related groups using the Wilcoxon test. The confidence level p < 0.05 was taken as statistically significant changes.

RESULTS AND DISCUSSION

All patients underwent a standard examination, including the collection of complaints, anamnesis, examination, laboratory methods (hemogram with the determination of the relative and absolute number of eosinophils, the concentration of total serum IgE), imaging methods (chest X-ray), and spirography in children older than 5 years.

A brief clinical description of patients depending on the severity of BA is presented in Table 1. In the main group, patients with mild, moderate, and severe BA did not differ in age and gender (p > 0.05). Fifty-nine (52.3%) patients with severe disease had a burdened family history of BA. Allergic rhinitis was dominant for 36 (31.8%) patients with severe asthma, the frequency of atopic dermatitis in the groups did not significantly differ, making up 30.3% (10), 36.1% (11), and 22.7% (10) for mild BA, moderate, and severe asthma, respectively (p > 0.05). Therapy in the Pulmonology Department included inhalation of budesonide suspension and ipratropium bromide/phenoterol via a nebulizer. The duration of hospitalization, depending on the severity, did not significantly differ (p > 0.05). According to the results of laboratory examination, eosinophilia and an increase in the level of IgE were detected for patients of the main group, and are more pronounced in moderate and severe BA. The X-ray picture of mild asthma for 26 (78.8%) children was characterized by a diffuse enrichment of the lung pattern. In severe cases, 21 (47.7%) patients showed signs of lung tissue hyperinflation.

 

Table 1 / Таблица 1 Clinical characteristics of patients in the main cohort Клиническая характеристика пациентов основной группы
Criteria / Критерии	Light BA, n = 33 / Легкая БА, n = 33	Moderate BA, n = 36 /Среднетяжелая БА, n = 36	Severe BA, n = 44 /Тяжелая БА, n = 44
Boy/girl / Мальчики/девочки	20/13	25/11	24/20
Age, years (Ме, Q25–Q75) / Возраст, лет (Ме, Q25–Q75)	5.5 (2.0–8.0)	7.0 (3.0–9.0)	8.5 (4.0–11.0)
Duration of the disease, years (Ме, Q25–Q75) / Длительность заболевания, лет (Ме, Q25–Q75)	3.0 (1.5–4.0)	4.0 (3.0–7.0)	6.0 (4.0–9.0)
BA in parents, abs. (%) / БА у родителей, абс. (%)	4 (12.1)	13 (36.1)	23 (52.3)*
Atopic dermatitis, abs. (%) / Атопический дерматит, абс. (%)	10 (30.3)	11 (36.1)	10 (22.7)
Allergic rhinitis, abs. (%) / Аллергический ринит, абс. (%)	6 (14.3)	10 (27.7)	14 (31.8)
Serum immunoglobulin E, IU/ml (Ме, Q25–Q75) / Сывороточный иммуноглобулин Е, МЕ/мл (Ме, Q25–Q75)	88.5 (56.75–128.5)	216.5 (94.0–360.5)	183.5 (154.3–215.6)
Eosinophils (Ме, Q25–Q75) / Эозинофилы (Ме, Q25–Q75)	182.5 (130.5–351.0)	295.0 (212.0–782.0)	369.5 (208.0–565.8)
Enrichment of the lung pattern, abs. (%) / Обогащение легочного рисунка, абс. (%)	33 (78.6)	30 (83.3)	23 (52.3)
Hyperinflation of the lungs, abs. (%) / Гиперинфляция легких, абс. (%)	2.4 (1)	16.6 (6)	47.7 (21)*
FEV1 – Forced Expiratory Volume in one second, l/min (Ме, Q25–Q75) / ОФВ1 — Объем форсированного выдоха за первую секунду, л/мин (Ме, Q25–Q75)	76.5 (68.0–89.0)	74.0 (58.0–83.0)	51.0* (46.0–71.0)
Duration of hospitalization, days (Ме, Q25–Q75) / Длительность госпитализации, дней (Ме, Q25–Q75)	12.0 (9.0–14.0)	14.0 (12.0–14.0)	13.5 (9.5–15.0)
Note. * Significant differences in the Mann – Whitney criterion in comparison with a group of patients with mild asthma: р < 0.05. BA – bronchial asthma. Примечание. * Достоверные различия по критерию Манна – Уитни в сравнении с группой пациентов с легкой бронхиальной астмой — р < 0,05. БА — бронхиальная астма.

 

All children received basic therapy for at least 3 months before the start of the study: 3 (2.6 %) received montelukast, 38 (33.6 %) received low doses of inhaled corticosteroids (fluticasone propionate, beclomethasone dipropionate, up to 250 mcg per day), and 16 (14.2%) and 44 (38.9%) patients with moderate and severe asthma received medium doses and high doses (fluticasone propionate, beclomethasone dipropionate, fluticasone/salmeterol, 500–1000 mcg per day), respectively.

The acoustic work of breathing was analyzed for patients with mild, moderate, and severe BA. A significant advantage of the method for evaluating ventilation disorders using the computer diagnostic complex “Pattern 1” is its ability to detect disorders that are not registered during auscultation, as well as the ability to apply this method for children from the newborn period, which is impossible when using spirometry. In the initial assessment of pulmonary ventilation, a correlation analysis was performed between the acoustic coefficient of the high-frequency range (K₂) and the forced expiratory volume in the first second (FEV1), a significant feedback r_s = −0.61 (p < 0.05) was found, indicating a decrease in bronchial patency with an increase in acoustic indicators. The results are shown in Figs. 1-3.

 

Fig. 1. Dynamics of the acoustic work of respiration coefficient at the level of small bronchi (K2) under the electromagnetic influence of “Aster” in patients with mild bronchial asthma

Рис. 1. Динамика коэффициента акустической работы дыхания на уровне мелких бронхов (К₂) при электромагнитном воздействии аппарата «Астер» у пациентов с легкой бронхиальной астмой

 

Fig. 2. Dynamics of the coefficient of acoustic work of respiration at the level of small bronchi (K2) under the electromagnetic influence of “Aster” in patients with moderate bronchial asthma

Рис. 2. Динамика коэффициента акустической работы дыхания на уровне мелких бронхов (К₂) при электромагнитном воздействии аппарата «Астер» у пациентов со среднетяжелой бронхиальной астмой

 

Fig. 3. Dynamics of the coefficient of acoustic work of respiration at the level of small bronchi (K2) under the electromagnetic influence of “Aster” in patients with severe bronchial asthma

Рис. 3. Динамика коэффициента акустической работы дыхания на уровне мелких бронхов (К₂) при электромагнитном воздействии аппарата «Астер» у пациентов с тяжелой бронхиальной астмой

 

In the course of our study, exposure to ultra-weak electromagnetic waves led to a decrease in the acoustic work of respiration, and therefore to a decrease in obstructive disorders in all age subgroups of patients with mild BA. Note that with a mild course of the disease, the same direction of changes in bronchial patency was registered at both the 5^th and 15^th minutes of the study. The greatest decrease in K₂ was recorded for patients with mild asthma of age 7–11 years (5.7 times, p < 0.05), and the smallest in an older age group (12–17 year ) – 1.4 times (p > 0.05) (Fig. 1).

With moderate BA, 5 minutes after exposure to the Aster unit, children aged 3–6 and 7–11 years old showed a slight increase in the acoustic work of breathing at the level of medium and small-caliber bronchi. By the 15^th minute, a significant regression of ventilation disorders was observed for patients aged 7–11 years (by 3.5 times, p < 0.05) and a tendency of K₂ to decrease among patients aged 12–17 years, in comparison with preschool-aged individuals who showed a slight decrease in bronchial patency compared to the baseline level (Fig. 2).

The patency of the bronchi of patients with severe asthma after a single exposure to electromagnetic waves had the form of a “plateau” in the subgroups of patients aged 3–6 and 7–11 years, remaining in the range of initial values by the end of the 15^th minute of observation. Among patients aged 12–17 years with a severe BA, a slight increase in acoustic respiration was registered (p > 0.05) (Fig. 3).

We assume that a single exposure to electromagnetic radiation may be short-lived, but improved microcirculation in the bronchial wall leads to a decrease in edema, improved sputum removal from the bronchi, which was noted by researchers during a long-term therapy (14–20 days) of patients with obstructive bronchitis, BA, and cystic fibrosis [1, 2, 9, 12]. This study showed signs of improved airflow in the respiratory tract.

To assess the clinical effectiveness of the Aster device, group A patients (20 children with an allergic variant of BA) received basic therapy in combination with electromagnetic radiation from the Aster device for 7 days. Patients in group B (comparison group) received only basic therapy. The dynamics of symptoms of the disease was evaluated on a scale of cough severity (0 – no symptoms, 1 – slightly, for a short period, 2 – short episodes during the day, 3 – most of the day, awakens during night sleep, 4 – most of the day with impaired daytime activity and sleep). A cough severity was assessed on days 1, 3, 5, and 7. The modes of basic therapy are presented in Table 2.

 

Table 2 / Таблица 2 Basic therapy regimens for patients with bronchial asthma Режимы базисной терапии пациентов с бронхиальной астмой
Groups / Группы	The severity of bronchial asthma / Степень тяжести бронхиальной астмы	Montelukast /Монтелукаст	Inhaled corticosteroids (up to 250 mcg/s) / Ингаляционные кортикостероиды (до 250 мкг/с)	Inhaled corticosteroids (500–1000 mcg / s) / Ингаляционные кортикостероиды (500–1000 мкг/с)
Group A (basic therapy + Aster) / Группа А (базисная терапия + «Астер»)	Light, n = 5 / Легкая, n = 5	3 (15 %)	2 (10 %)	–
	Moderate, n = 9 / Среднетяжелая, n = 9	–	4 (20 %)	5 (25 %)
	Severe asthma, n = 6 / Тяжелая, n = 6	–	–	6 (30 %)
Group B (basic therapy) / Группа В (базисная терапия)	Light, n = 3 / Легкая, n = 3	3 (25 %)	–	–
	Moderate, n = 4 / Среднетяжелая, n = 4	–	4 (33.3 %)	–
	Severe asthma, n = 5 / Тяжелая, n = 5	–	–	5 (41.7 %)

 

The dynamics of children’s condition in groups A and B after different therapy modes are shown in Table 3.

 

Table 3 / Таблица 3 Dynamics of the state of patients in groups A and B depending on the treatment regimen, Me (Q25–Q75) Динамика состояния пациентов групп А и В в зависимости от режима терапии, Me (Q25–Q75)
Groups / Группы	The severity of bronchial asthma/ Степень тяжести бронхиальной астмы	Cough, points / Кашель, баллы
		1 day / 1-й день	3 day / 3-й день	5 day / 5-й день	7 day / 7-й день
Group A (basic therapy + Aster) / Группа А (базисная терапия + «Астер»)	Light, n = 5 / Легкая, n = 5	2 (1–2)	1 (1–1)	1 (0–1)	0 (0–1)
	Moderate, n = 9 / Среднетяжелая, n = 9	3 (1–3)	2 (1–2)	1 (0–1)	1 (1–1)
	Severe asthma, n = 6 / Тяжелая, n = 6	3 (2–3)	2 (2–2)	1(1–2)	1(0–2)
Group B (basic therapy) / Группа В (базисная терапия)	Light, n = 3 / Легкая, n = 3	2 (2–3)	2 (2–2)	1 (1–2)	0 (0–1)
	Moderate, n = 4 / Среднетяжелая, n = 4	2.5 (2–3)	2 (0–2)	2 (1–2)	1 (0–1)
	Severe asthma, n = 5 / Тяжелая, n = 5	3 (3–3)	3 (2–3)	2 (2–2)	1.5 (1–2)
Note. No significant differences were found in the compared groups: р > 0.05. Примечание. Достоверные различия в сравниваемых группах не выявлены: р > 0.05.

 

In the first days, the dynamics of cough severity after traditional therapy and treatment in combination with the Aster unit is almost the same, but children who received physiotherapy with electromagnetic radiation stopped night cough by the 5^th day of treatment and were slightly disturbed for a short period by the 7^th day, while 6 (50 %) patients of group B had 2–3-fold episodes of paroxysmal cough by this point of the study. At the same time, the acoustic coefficient of K₂ decreased from the initial 0.63 to 0.1 (p < 0.05), indicating a decrease in obstructive pulmonary ventilation disorders.

Thus, a single application of electromagnetic radiation changes the acoustic parameters of pulmonary ventilation. The least labile with a single microwave exposure is the acoustic work of breathing for older children and severe BA.

The combination of basic therapy with electromagnetic radiation for 7 days caused a more expressed effect on the clinical condition.

The limit of this study is the small number of patients who received traditional therapy in combination with the electromagnetic influence of a non-thermal intensity of the Aster unit, which does not allow a reliable acoustic assessment of the functional state of the bronchopulmonary system and hence the need for further research.

CONCLUSION

Summarizing the results, we draw the following conclusions:

1. With a single exposure to ultra-weak electromagnetic waves of non-thermal intensity, the greatest change in acoustic parameters is registered for patients with mild BA in the age groups 3–6, 7–11, and 12–17 years, as well as in the group of 7–11 years with moderate BA. The minimum change was observed in those with severe BA.
2. A possible response to a single exposure to ultra-weak waves of a non-thermal intensity (as an addition to ф basic therapy) in patients with BA was improved bronchial patency.

¹ Registration certificate № FS 022a2005/2581-05 dated 2005/12/19.

About the authors

Natalya L. Potapova

Chita State Medical Academy, Ministry of Healthcare of the Russian Federation

Author for correspondence.
Email: nataliapotap@yandex.ru

MD, PhD, Associate Professor, Head Department of Outpatient Pediatrics with a Course of Medical Rehabilitation

Russian Federation, Chita

Inessa N. Gaymolenko

Chita State Medical Academy, Ministry of Healthcare of the Russian Federation

Email: ingaim@mail.ru

MD, PhD, Dr. Med. Sci., Professor, Head Department of Pediatrics

Russian Federation, Chita

References

Supplementary files