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Preterm infants: features of cerebral hemodynamics at various ways of delivery
Tumaeva Tatiana Stanislavovna, Mordovian Republican Clinical Perinatal Center, Head of the department of functional diagnostics E-mail: tstumaeva@mail.ru Naumenko Elena Ivanovna, Mordovia State University, Chair of Pediatrics, Assistant professor E-mail: ei-naumenko@yandex.ru Samoshkina Elena Semenovna, Mordovia State University, Chair of Pediatrics, Assistant professor E-mail: esamoshkina@yandex.ru Vereshchagina Veronica Sergeevna, Mordovia State University, Chair of Pediatrics, Assistant professor E-mail: verav4@yandex.ru
Preterm infants: features of cerebral hemodynamics at various ways of delivery
Abstract: Premature infants are at high risk for the formation of perinatal pathology. Complicated antenatal and intrapartum period, the combined effect on the fetus and newborn hypoxia-ischemia, operative delivery, preterm pregnancies result in persistent violation of cerebral hemodynamics within 1 month of life.
Keywords: cerebral hemodynamics, premature newborns, cesarean section, hypoxia-ischemia, neonatal period.
Introduction. Currently, one of the ways to reduce perinatal pathology recognized cesarean delivery [1; 2]. The introduction of new technologies in operational obstetrics expanded the indications for cesarean section, above all, in the interests of the fetus. This refers to the surgical delivery intrapartum risk factor, the impact of which on the body of the newborn is not yet fully studied [3; 4; 5]. Perfecting intensive care and neonatal intensive care has made it possible not only nursing children with different pathologies of the perinatal period, and very preterm [6; 7]. This has resulted in an increased incidence of childhood, especially the central nervous system [8; 9]. Deviations in the development of neuropsychiatric features in children are attracted to the currently increasing attention of researchers from the perspective of the relationship with the complicated antenatal, intrapartum period of development of the organism, postnatal maladjustment [10;
11; 12]. The purpose of research — to assess the impact of premature pregnancy undergoing hypoxia-ischemia and cesarean delivery on cerebral hemodynamics in infants in the neonatal period.
Patients and methods. The study included 270 preterm children learned different ways of delivery, had clinical signs of hypoxia-ischemia transferred. The following groups: I group — 170 preterm born by Caesarean section; II group — 100 babies born naturally. Exclusion criteria were: birth trauma, infectious processes, syndromic form of disease, congenital malformations. The control group (III) — 57 full-term infants from physiological pregnancy and birth with Apgar scores 8.8 points. Comprehensive survey of newborns included ultrasound brain structures, Doppler cerebral vessels using color mapping and spectral Doppler, performed on instruments «TOSHIBA APLIO MX» (Japan), «TOSHIBA VIAMO» (Japan) with multifrequency transducers 5-9MGts. Scanning
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Section 1. Clinical medicine
was performed in the standard planes. The spectral Doppler sonography was performed in intracranial arteries and veins with the assessment of qualitative and quantitative characteristics, including resistance index (RI), maximum systolic (Vmax) and diastolic (Vmin) blood flow velocities; evaluated the usefulness of the outflow vein of Galen. Statistical data processing was performed using the application package «Statistica».
Results and discussion. Clinical characteristics of the children included in the study are shown in Table 1. Apgar score in preterm infants correlated with gestational age and severity ofhypoxia-ischemia
transferred (rs = 0,692, p = 0,004 and rs = 0,906, p = 0,000, respectively). According to the results of complex clinical and instrumental examination of the newborn groups I and II were detected lesion of the central nervous system of varying severity. This determines the duration of the syndrome of oppression, the presence of neonatal seizures, presence and dynamics of structural changes in the brain by ultrasound. Most newborns in need of intensive care and nursing in intensive care (7683%). The most lengthy resuscitation, respiratory support, tube feeding required of preterm babies born by Caesarean section (p> 0,05).
Table 1. - Clinical characteristics of the children included in the study
Indicators I group, n=170 II group, n=100 III group, n=57
Gender:
boys, n (%) 75(44%) 54 (54%) 27 (46%)
girls, n (%) 95 (56%) 46 (46%) 30 (53%)
Weight, g, Range 860-3560 700-3210 2950-4110
M±m 2169,1±46,1 2136,7±54,1 3427,3±160,5
Apgar, 1min, 1-8 1-7 8-9
Apgar, 5min 3-8 4-8 8-9
Cerebral ischemia I/II/III,% 25/39/36 29/43/28 -
All newborns 1-2 days of life held ultrasound Doppler of the brain and cerebral vessels. Because of structural damage in premature brain prevailed isolated ischemic changes (Table 2). Violations of mixed nature (ischemic-hemorrhagic) often formed in children born by cesarean section. The frequency and nature of the structural changes were closely related to the severity of hypoxic-
ischemic brain damage (^2 = 56,18; p = 0,000), with a gestational age of the children surveyed (^2 = 46,844; p = 0,000). It should be noted that the combined violations were more common in preterm infants undergoing cerebral ischemia of moderate and severe (^ = 8,03, p = 0,006 and X = 12,04, p = 0,001, respectively).
Table 2. - Structural changes in the brain according to the US in the early neonatal period
Indicators I group, n=170 II group, n=100 III group, n=57
Age norm 3 (1,8%)** 3 (3%)** 55 (96,5%)
Isolated ischemic changes 146 (85,8%)** 88 (88%)** 2 (3,5%)
Changes to the combined nature 21 (12,3%)** 9 (9%)* -
Note: * — significant differences in preterm infants from the control at p <0,005; ** — significant differences in preterm infants from the control atp <0,001
One of the major factors leading to structural damage to the brain, the cerebral blood flow is on the background of undergoing hypoxia-ischemia. Hemodynamic changes resulting from the unfavorable course ofthe perinatal period and related to violation of autoregulation of cerebral blood flow, promote the development of hemorrhagic
complications and subsequent destructive changes of the brain substance. In our study, when evaluating the average values of the main hemodynamic parameters of blood vessels and venous all newborns undergoing hypoxia-ischemia, regardless ofthe mode of delivery, it identified a number of characteristics (Table 3). According to the index RI can be judged
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Preterm infants: features of cerebral hemodynamics at various ways of delivery
on a higher tone of blood vessels in children groups I and II, but reached statistical significance only in premature figures after surgical delivery. At the same time all premature attracted attention a significant reduction in the linear velocity of systolic and diastolic blood flow (р <0,001), indicating that the
formation of pathological vascular reactions and, as a result, the prevalence of ischemic processes in the brain tissue (r = 0,925, p = 0,000). Vasomotor disorders also affects venous outflow. Premature babies tended to reduce the rate of venous outflow, especially in those born by surgery (p> 0,05).
Table 3. - An analysis of some indicators of cerebral blood flow in the early neonatal period
Indicators I group., n=170 II group., n=100 III group., n=57
V max, cm/sec 13,1-57,2 31,1±0,69** 17,1-47,5 30,6±1,16** 29,0-61,1 39,7±1,21
V min, cm/sec 0,0-20,3 8,5±0,28** 1,6-13,3 8,3±0,42** 5,7-18,0 11,7±0,57
RI 0,47-1,0 0,74±0,01* 0,58-1,0 0,73±0,01 0,58-0,81 0,70±0,01
V venous outflow, cm/sec 1,4-11,7 5,1±0,12 3,0-10,4 5,4±0,19 4,2-7,0 5,5±0,13
Note: * — significant differences in preterm infants from the control at p <0,05; ** — significant differences in preterm infants from the control atp <0,001
Dynamic control of the formation of cerebral hemodynamics was performed at the age of 7, 14 and 21 days. During the first month of life was recorded by a natural increase in the linear blood flow indices in children studied groups. Thus the end of the neonatal period all preterm, especially after caesarean remained elevated resistive characteristics (RI) cerebral vascular bed, compared with the control group (0,77 ± 0,00 0,74 ± 0,01 and 0,70 ± 0,01 respectively, p <0,05). High resistance vascular bed shaped lower diastolic blood flow (Vmin), that is significantly different infants born surgically (11,8 ± 0,41 cm/s versus 13,2 ± 0,62 cm/s and 13,8 ± 0 68 cm/s, p <0,05, respectively). Resistant nature of arterial flow supported venous dysfunction, which contributed to a significant reduction in the average linear velocity of venous outflow, especially in preterm caesarean section (7,8 ± 0,25 cm/sec and 8,1 ± 0,36 cm/sec to 8, 9 ± 0,19 cm/s, p <0,005). Thus, the dynamic control over the neonatal period
revealed a slow process of recovery of cerebral hemodynamics in preterm infants, particularly at birth by Caesarean section.
Conclusions. Adverse during the perinatal period, particularly with concomitant effects on the fetus and newborn full-term pregnancy, hypoxia-ischemia, operative delivery, results in persistent disruption of cerebral blood flow. In-depth study of various parts of hemodynamic adaptation, in particular the blood supply to the brain with the assessment of qualitative and quantitative indicators, enables the early detection of disorders of cerebral hemodynamics (increased resistance of the vascular bed, change of linear characteristics of the arterial and venous blood flow). Children born by Caesarean section and had undergone hypoxia-ischemia, especially premature, constitute a group at high risk of maladjustment in the perinatal period and the formation ofpathological conditions in the next age periods.
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