RU2271737C2 - Method for differential evaluation of fetal state - Google Patents

Abstract

FIELD: medicine, obstetrics, neonatology, pediatrics.

SUBSTANCE: one should apply three electrodes at pregnant woman's thorax, abdominal electrodes should be applied in epigastric and hypogastric areas, in area of the upper and lower hypochondrium, in left- and right-hand inguinal area. Then one should determine average value of R-R intervals, heart rate, calculate the mode, variation scope of cardiointervals' duration and mode's amplitude. Tension index (TI) should be, also, calculated to detect fetal state. The innovation enables to increase information value of differential evaluation.

EFFECT: higher accuracy of diagnostics.

4 ex, 1 tbl

Description

The invention relates to medicine, obstetrics, neonatology, pediatrics, and specifically to methods for differential assessment of the condition of the fetus.

The closest in technical essence to the proposed one is a method for assessing the condition of the fetus using antenatal cardiotocography, performed by applying two abdominal sensors: in the field of stable registration of fetal heart contractions and in the uterine fundus and subsequent ECG recording [1], based on registration of heart rate the fetus and their changes depending on uterine contractions and the action of external stimuli, with a heart rate of 120-160 beats / min, a satisfactory condition of the fetus is judged, with a decrease in heart rate more more than 120 beats / min and with an increase of more than 160 beats / min judge the violation of the welfare of the fetus. Moreover, this method is not accurate enough, informative, sensitive to motor activity of the fetus, long in time.

A new technical task is to increase the accuracy, sensitivity, information content and simplify the method.

The problem is solved in a new way of differential assessment of the fetus, which consists in placing the abdominal electrodes and subsequent registration of the fetal heart rhythm structure and determining the state of its adaptive reactions, with three electrodes placed on the chest of a pregnant woman in the heart region (V1, V3, V5), and abdominal electrodes are placed in the region of the vertices of the hexagon, the center of which is the umbilical ring of the abdomen, and then determine the average value of the intervals RR, heart rate H C, Mo mode, variation range duration cardiointervals dX, mode and amplitude AMo index calculated voltage by the formula:

IN = AMo / (2 × Mo × dX)

and with IN from 250 to 350 conventional units, the adaptive type of fetal state is determined, with IN from 351 to 450, the adaptive-compensatory type of fetal state is determined, with IN from 451 to 550, the compensatory type of fetal state is determined, and with IN from 551 and higher, the maladaptive type is determined the condition of the fetus.

The method is as follows: to assess the condition of the fetus, use the original device developed by employees of the Department of Biological and Medical Cybernetics, Siberian State Medical University, which includes one differential channel for recording the bioelectric activity of the mother’s heart and three differential channels for recording the abdominal signal of the fetus [2]. The basis of this program is the method of cardiointervalography (CIG), based on a mathematical analysis of heart rhythm. Its essence lies in the ability to assess the rhythm and adequacy of the sinus node, revealing the mechanisms of various changes in the body in the process of adaptive-compensatory response [3].

The device consists of a computer, an ECG-trigger cardiointervalometric module, an interface module, three chest and six abdominal electrodes, and a software package. Recording a cardiointervalogram for pregnant women is carried out in the third trimester, in the period 37-40 weeks. Studies are performed in the morning, under comfortable conditions: normal lighting and room temperature, calm environment, no distracting and irritating factors (conversation, noise, presence of strangers) for 15 minutes. Electrodes lubricated with an electrically conductive gel are applied to the chest of a pregnant woman in the region of the heart (V1, V3, V5), and 6 abdominal electrodes are distributed throughout the woman’s abdomen and placed in the region of the vertices of the hexagon, the center of which is the umbilical ring of the abdomen, and the structure of the cardiac fetal activity. We have proposed this scheme of abdominal leads to improve noise immunity, and also so that the signal size does not depend on the position of the fetus. The processed signal is equal to the sum of the signals of all the electrodes. Subsequently, using adaptive filtering, the fetal heart rhythm structure is extracted from the combined signal of the mother and the fetus. At the same time, the rhythmic characteristics of the CIG of the fetus, i.e. the time intervals of fetal heart contraction (RR) and the nature of the distribution of these intervals over time.

For statistical analysis of cardiointervalography data, indicators recommended by cardiac rhythmological standards are calculated [4], according to which:

R-R sr (sec) - the average value of R-R intervals, reflects the average level of heart rate. With a decrease in heart rate, R-R cf increases, with increased frequency it decreases. R-R cf is ultimately the result of all regulatory influences both on the cardiovascular system as a whole and on the heart in particular. Therefore, this indicator serves as a vivid characteristic of the level of functioning of the circulatory system. Deviations of the value of R-R cf from the individual norm signals a change (increase) in the load on the cardiovascular system or the occurrence of pathological changes [5];

Heart rate (bpm) - heart rate. Reflects the integrated level of functioning of the sinus node;

Mo (sec) - fashion, the most common value of cardiointerval, characterizes the humoral channel of heart rate regulation and the level of system functioning; characterizes the activity of the humoral channel of heart rate regulation. With an increase in sympathetic tone, the mode, as a rule, decreases; an increase in parasympathetic tone leads to an increase in fashion [5];

dX (sec) is the variational range of the duration of the cardio-intervals (the difference between the maximum and minimum values of the R-R intervals) characterizes the level of activity of the parasympathetic link of the autonomic nervous system;

AMo (%) - the amplitude of the mode, the number of intervals corresponding to Mo, expressed as a percentage. Determines the state of activity of the sympathetic part of the autonomic nervous system;

IN (arbitrary units) - voltage index, is an integral indicator of the level of functioning of the central circuit of regulation of heart rhythm, calculated by the formula IN = AMo / (2 × Mo × dX). It characterizes the degree of tension of adaptation systems to various conditions, with ID from 250 to 350 conventional units determine the adaptive type of fetal state, with ID from 351 to 450 determine the adaptive-compensatory type of fetal state, with IN from 451 to 550 determine the compensatory type of fetal state and ID 551 and higher determine the maladaptive type of the fetus.

Example 1. Woman X. age 23, student. I pregnancy - 40 weeks, physiological course. Heredity is not burdened.

By antenatal cardiography: normal fetus.

A study was carried out according to the proposed method: RR - 497.2 sec; Heart rate - 120.68 beats / min; dX - 0.10 sec; Mo - 0.59 sec; AMo - 36.34%; IN - 346 c.u. Defined as an adaptive type of fetal state.

The baby was born with a gestational age of 40-41 weeks. from urgent deliveries in the head presentation with an assessment on the Apgar scale of 8-9 points. The birth weight is 3250 g, length 52 cm, head circumference 34 cm, chest circumference 32 cm. The condition of the baby after birth is satisfactory. The scream is loud, emotional. He held the middle position. Spontaneous motor activity is sufficient. Muscle tone is satisfactory, slightly increased in the extensor flexors. Reflexes of the newborn performed in full. The skin is pink, clean. Visible mucous membranes are clean, shiny. The subcutaneous fat layer is sufficiently developed, evenly distributed. Respiratory rate - 48 breaths per minute. Pueril breath. Heart sounds are clear, rhythmic. Heart rate 138 beats per minute. The abdomen is round in shape, soft on palpation. The liver protruded 1.5 cm from the edge of the costal arch, the spleen was not palpable. Urination is free. The baby's condition remained stable throughout the early neonatal period. On the 5th day, the child was discharged home in satisfactory condition, with a diagnosis of "Full-term gestational age."

Example 2. Woman L., age 25, housewife. I pregnancy, gestational age 35 weeks. I trimester without features, II trimester - mild gestosis combined with hypertensive type of VSD. A history of chronic tonsillitis in remission.

By antenatal cardiography: initial signs of impaired fetal status.

A study was carried out according to the proposed method: RR - 311.1 sec; Heart rate - 178 beats / min; dX - 0.10 sec; Mo - 0.41 sec; AMo - 35.14%; IN - 415 c.u. Defined as an adaptive-compensatory type of fetal state.

The baby was born with a gestational age of 38-39 weeks. from urgent delivery in the head presentation. In childbirth, secondary weakness of labor, rhodostimulation. The Apgar score is 7-8 points. Weight at birth is 3010 g, length is 50 cm, head circumference is 33 cm, chest circumference is 32 cm. The child's condition after birth is satisfactory. The scream is loud, emotional. Spontaneous motor activity is sufficient. When screaming, fine tremor of hands and lower jaw was noted. Muscle tone is increased in the extensor flexors. Reflexes of newborns performed in full. The skin is pink, clean, acrocyanosis was noted. Visible mucous membranes are clean, shiny. The subcutaneous fat layer is sufficiently developed, evenly distributed. Respiratory rate - 46 breaths per minute. Pueril breath. Heart sounds are clear, rhythmic. The heart rate is 136 beats per minute. The abdomen is round in shape, soft on palpation. The liver protruded 1.5 cm from the edge of the costal arch, the spleen was not palpable. Urination is free. On day 3, icteric staining of the skin on the face was noted; on the buttocks - single erythematous, slightly dense spots. Visible mucous membranes are clean, shiny.

Dynamics of clinical signs: primary weight loss was 8%, its recovery began from 6 days of life. Jaundice of the skin intensified by 5 days, disappeared by 7 days. Elements of toxic erythema disappeared on the 6th day. On the 8th day the child was discharged home in satisfactory condition, with a diagnosis of "Full-term gestational age."

Example 3. S., age 22, student. Pregnancy III; I - mini-abortion; II - honey. abortion at 16 weeks, without complications. Real pregnancy 30 weeks; I and II trimester without features. III trimester, threat of interruption at 27 weeks, combined gestosis of moderate severity against the background of hypertensive-type VSD, inpatient treatment.

By antenatal cardiography: initial signs of impaired fetal status.

A study according to the proposed method: RR - 341.6 sec; Heart rate - 192 bpm; dX - 0.08 sec; Mo - 0.41 sec; AMo - 34.41%; IN - 467 c.u. Defined as a compensatory type of fetal condition.

The child was born with a gestational age of 38-39 weeks from the 3rd pregnancy, 1 prolonged labor in the head presentation with an assessment on the Apgar scale of 6-8 points. The birth weight is 3032 g, length 52 cm, head circumference 34 cm, chest circumference 33 cm. Baby's condition after birth of moderate severity. The scream is loud, short. He didn’t hold on to the middle position; he tumbled to one side. Spontaneous motor activity is increased. A prolonged finely spread tremor of the limbs at rest was noted. Muscle tone is increased. Hyperreflexia, revitalization of tendon reflexes was noted. On examination - Moro's spontaneous reflex. The skin is pale pink, clean. Visible mucous membranes are clean, shiny. The subcutaneous fat layer is underdeveloped. Respiratory rate - 52 breaths per minute. Pueril breath. Heart sounds are clear, rhythmic. Heart rate 142 beats per minute. The abdomen is round in shape, soft on palpation. The liver protruded 1.5 cm from the edge of the costal arch, the spleen was not palpable. Urination is free. Accordingly, the severity of the condition and clinical symptoms, the child received the full range of necessary therapeutic measures.

Dynamics of clinical signs: primary weight loss was 8.6%, its restoration began from 6 days of life. By day 7, the neurological symptoms disappeared. On the 8th day the child was discharged home in satisfactory condition, with a diagnosis of the main "Hypoxic-ischemic encephalopathy of the first degree, hyper-excitability syndrome."

Associated: “Full-term. Intrauterine malnutrition of the first degree. "

Example 4. Z. age of 20 weeks. Pregnancy 2nd. I pregnancy - honey. abortion at 12 weeks, without complications. Real pregnancy: gestational age 30 weeks; I and II trimester without features. III trimester - ureaplasmosis at 25 weeks, treated. On ultrasound, indirect signs of FPF, relative polyhydramnios.

By antenatal cardiography: a pronounced violation of the condition of the fetus.

A study was conducted according to the proposed method: RR - 295 sec; Heart rate - 202 beats / min; dX - 0.07 sec; Mo - 0.39 sec; AMo - 43.38%; IN - 777.09 cu Defined as a maladaptive type of fetal state.

The baby was born with a gestational age of 38-39 weeks. from the 2nd pregnancy, 1-term delivery in the head presentation with an assessment on the Hangar scale of 4-6 points. Birth weight 2696 g, length 51 cm, head circumference 34 cm, chest circumference 33 cm. Resuscitation measures were carried out according to order No. 372 of 12/28/1995, "On improving primary and resuscitation care for newborns in the maternity ward." The condition of the child after birth of moderate severity. The cry is weak, short. He didn’t hold on to the middle position; he tumbled to one side. Spontaneous motor activity was inhibited. Muscle tone is reduced, reflexes of the newborn are depressed, eyes are closed. The skin is pale pink, clean. Visible mucous membranes are clean, shiny. The subcutaneous fat layer is developed, thinned. The respiratory rate is 54 breaths per minute. Pueril breath. Heart sounds are muffled, rhythmic. Heart rate 144 beats per minute. The abdomen is round in shape, soft on palpation. The liver protruded 1.5 cm from the edge of the costal arch, the spleen was not palpable. Urination is free. Accordingly, the severity of the condition determined due to the proposed method and clinical symptoms, the child received the full range of necessary therapeutic and regimen measures.

Dynamics of clinical signs: primary weight loss was 10%, its recovery began from 7 days of life. Against the background of the treatment, by 7 days neurological symptoms persisted. On the 7th day, the child was transferred to the neonatal pathology department with a diagnosis of the main “Perinatal CNS damage, hypoxic genesis, general depression syndrome, moderate severity, acute period”.

Associated: “Full-term. Intrauterine hypotrophy of the second degree. "

The proposed criteria were selected based on the analysis of clinical studies of pregnant women with complicated and uncomplicated pregnancy. The indicators of fetal cardiointervalography for various types of adaptation are presented in the table.

By random sampling, 70 pregnant women in the third trimester of pregnancy (27-41 weeks) were examined in a maternity ward of maternity hospital No. 1 of Tomsk. As a result of the study, pregnant women were divided into four groups depending on the level of fetal IN: the first group consisted of 14 women with an adaptive type of fetal condition; Group 2 - 28 pregnant women with adaptive-compensatory type of fetal condition; Group 3 - 16 - with a compensatory type of fetal condition; and group 4 - 11 pregnant women with a maladaptive type of fetal condition. The division of pregnant women into groups depending on the functional state of the fetus was confirmed by a study of the functional assessment of the fetus using cardiotocography based on recording the heart rate of the fetus and their changes depending on uterine contractions and the action of external stimuli (r = 0.69, p <0.05 )

During the correlation analysis, the adaptive type had a high correlation with the physiological course of pregnancy (r = 0.89, p <0.001); adaptive-compensatory type of fetus state - with a burdened obstetric history (r = 0.45, p <0.05); mild gestosis and combined mild gestosis (r = -0.80, p <0.001), as well as a history of pregnancy, aggravated by a chronic course of infection in remission (r = -0.82, p <0.001). The compensatory type of fetal condition formed a correlation with the threat of termination in the III trimester of pregnancy (r = 0.60, p <0.01), with combined gestosis of moderate severity (r = 0.84, p <0.001). The maladaptive type of fetal condition was characterized by correlation with a somatic burden (r = 0.83, p <0.001) and a gynecological history (r = 0.44, p <0.05), with a threat of premature birth (r = 0.61, p <0.01), with acute third trimester infection (r = 0.49, p <0.01).

Further analysis of the course of the early neonatal period in newborns from the examined mothers revealed that in pregnant women of groups 3 and 4, the children had various complications of the neonatal period. The severity of these children was due to the following neurological symptoms in the form of hyper-excitability syndromes in 21 (87.5%) newborns and oppression in 3 (12.5%). 11 (45.8%) had jaundice from the end of the first day, anemia in 2 (8.3%) newborns. In 12 (50%) children there was a combination of these signs.

The authors found that the sensitivity of the method was 81.8%, the specificity was 66.7%, the predictive value of the positive result was 60.0%, the predictive value of the negative result was 85.7%.

Thus, the application of the proposed method for differential assessment of the fetus, consisting in a non-invasive study of the structure of the heart rhythm of the fetus, will allow you to objectively evaluate the adaptive reactions of the fetus with the greatest accuracy and information, correct them during pregnancy, develop optimal tactics of labor and delivery based on the forecast its condition and thereby reduce pathological manifestations in the intrapartum and neonatal periods.

Table Indicators of the structure of the heart rhythm of the fetus with various types of adaptation Indicators Types of adaptation Adaptive Adaptive-compensatory Compensatory Maladaptive R-R sr 380.55 ± 13.78 313.80 ± 6.91 306.30 ± 17.41 258.84 ± 11.96 p <0.001 p <0.01 p <0.001 p ₁ <0.001 Heart rate, beats / min 159.27 ± 5.01 193.91 ± 4.46 204.69 ± 8.72 235.45110,11 p <0.001 p <0.001 p <0.001 p ₁ <0.001 p ₂ <0.05 dX, sec 0.10 ± 0.002 0.09 ± 0.001 0.09 ± 0.001 0.08 ± 0.002 p <0.001 p <0.001 p ₁ <0.05 p ₁ <0.001 p ₂ <0,01 Mo, sec 0.48 ± 0.01 0.41 ± 0.006 0.40 ± 0.01 0.36 ± 0.01 p <0.001 p <0.001 p <0.001 p ₁ <0.001 p ₂ <0.05 AMo,% 29.37 ± 0.78 31.51 ± 0.48 36.40 ± 1.56 40.90 ± 2.27 p <0.05 p <0.001 p <0.001 p ₁ <0.001 p ₁ <0.001 IN, cu 302.78 ± 7.87 388.39 ± 8.20 488.63 ± 8.67 683.59 ± 54.53 p <0.001 p <0.001 p <0.001 p ₁ <0.001 p ₁ <0.001 p ₂ <0.001 Note: p - when compared with the adaptive type of fetal state; p ₁ - when compared with the adaptive-compensatory type of condition of the fetus; p ₂ - when compared with the compensatory type of condition of the fetus.

Literature

1. Trusov Yu.V. Functional conditions of the fetus / Yu. V. Trusov. - M.: MEDpress-inform, 2003 .-- 120 p.

2. Mikhalev E.V. The structure of the heart rhythm and clinical aspects of adaptation of premature infants with hypoxic-traumatic lesions of the central nervous system at the stages of rehabilitation: Abstract. dis .... cand. honey. sciences / E.V. Mikhalev. - Tomsk, 1997 .-- 24 p.

3. Baevsky R.M. Mathematical analysis of changes in heart rate during stress / R.M. Baevsky, O.I. Kirillov, S.Z. Kletskin. - M., 1984. - S.36-44.

4. Heart rate variability. Standards of measurement, psychological interpretation and clinical use // Eur. Heart J. - 1996 .-- Vol.17. - P.334-381.

5. Chimarov V.M. Analysis of cardiointervalograms in children: Guidelines / V.M. Chimarov, V.I. Krylov. - Tyumen, 1988 .-- 15 p.

Claims (1)

A method for differential assessment of the fetal condition, which consists in placing the abdominal electrodes and subsequent registration of the fetal heart rhythm structure, characterized in that the three electrodes are placed on the chest of a pregnant woman in the heart region V1, V3, V5, and the abdominal electrodes are placed in the region of the vertices of the hexagon, center of which the umbilical ring of the abdomen, the fetal heart rhythm structure is extracted from the joint signal of the mother and the fetus, and then the average value of the RR intervals and frequency are determined heart rate heart rate, Mo mode, variational range of duration of cardio intervals dX, amplitude of the AMO mode, and the stress index is calculated by the formula IN = AMo / (2 × Mo × dX) and for IN from 250 to 350 conventional units (cu) type of fetal condition, with ID from 351 to 450 cu determine the adaptive-compensatory type of fetal state, with ID from 451 to 550 cu determine the compensatory type of condition of the fetus and with IN from 551 cu and above determine the maladaptive type of condition of the fetus.