Biomedical subjects
Publications and source records attributed to P Zoban.
Hydrogen peroxide (H2O2) production in exhaled air was measured in ventilated preterm newborns at 5, 24 and 48 hours after delivery, using originally designed method of exhaled breath condensate (EBC) collection. H2O2 production in expired gas was 812+/-34 pmol/20 min during the first measurement and then declined to 389+/-21 at 24 hours and 259+/-26 pmol/20 min at 48 hours.
Acute lung injury occurs mostly in the very low birth weight and extremely low birth weight infants. The pathological process leading to acute lung injury includes immature and/or diseased lung that experienced oxidative stress, inflammation and mechanical insult with the bronchial, alveolar and capillary injuries and cell death. It may be the first step to the subsequent development of chronic lung disease of prematurity or bronchopulmonary dysplasia. The mechanisms of lung injury are extensively investigated in the experimental models and clinical studies, mostly performed on the adult patients. At present, the explanations of the mechanism(s) leading to lung tissue injury in tiny premature babies are just derived from these studies. Acute lung injury seems to be rather a syndrome than a well-defined nosological unit and is of multifactorial etiology. The purpose of this review is to discuss the main factors contributing to the development of acute lung injury in the very low or extremely low birth weight infants--lung immaturity, mechanical injury, oxidative stress and inflammation. Nevertheless, numerous other factors may influence the status of immature lung after delivery.
OBJECTIVE OF STUDY: a) assessment of the relationship between ileus of premature infants and the development of intestinal perforation in premature infants, b) suggestions of an optimal therapeutic procedure. In the study children (n = 50) are included a) with intestinal perforation in conjunction with impaired excretion of meconium (n = 22), b) with an ileus state based on obstruction of the ileum by a viscous meconium treated either surgically or conservatively (n = 28). Surgical treatment involved: a) establishment of a double ileostomy (n = 28), b) insertion of a T drain into the terminal ileum (n = 8), c) removal of meconium from the gut and its primary closure (n = 2). Conservative treatment in 11 children involved irrigography with an liquid contrast substance under X-ray control. The group of children with perforation was compared with the group of children without perforation, risk factors were evaluated by statistical methods. The necessity of ventilation (P = 0.051) and gestation age (P = 0.006) proved to be statistically significant risk factors for the development of perforation. Survival was not influenced by perforation. All 11 children treated conservatively survived, of 39 operated children 26 survived (66.7%). An early start of conservative treatment of ileus of premature infants reduces markedly the risk of intestinal perforation and can thus influence the survival of low birth weight neonates.
In this article the pathophysiology and diagnosis of neonatal respiratory distress syndrome as a primarily form of surfactant deficiency is disclosed. Attention is paid to surfactant composition, productive and secretion in the alveoli and metabolic turnover as well. From clinical point the view basic principles concerning the surfactant replacement is discussed. Surfactant minimizes the surface tension and friction between the gas molecules and lung tissues during breathing. It also helps keep lung tissues dry and alveoli patent. At 26 to 28 weeks of gestation alveolar ducts and bronchioles are present but pulmonary capillaries are not in close contact with them. Alveoli may not even be distinguishable. Surfactant develops all through gestation but does not surge until about the 34th week. Infants born before 35 weeks of gestation are at risk for respiratory distress syndrome which is at first characterised by decrease of lung compliance. It leads to progressive respiratory failure.
The method of assessment of the C1-inhibitor (C1-INH) based on activation of plasma precallicrein (PC) by the fragment of Hageman's factor (HFf) was described in a previous publication (6). It was recommended as an alternative of already described methods used for assessment of C1-INH. To define the reliability of the recommended method in plasma with a reduced PC level the authors used plasma of mothers where during childbirth as a rule a steep drop of this proenzyme occurs. In a group of 23 parturient women the plasma PC levels were assessed and were within the range from 0.067-0.397 U/ml incl. only 6 plasma specimens where the PC level varied within the range of normal donors, i.e. 0.319-0.438 U/ml (mean value mean = 0.369 +/- 0.035). The mean value in plasma of the mothers was 0.237 +/- 0.100. In both groups the C1-INH was assessed by the recommended method and by the method of callicrein inactivation. In the group of mothers the results of C1-INH correlated with estimations in plasma where the PC level was within the range from 42.5 to 107.6% of the mean PC value of donors (r = 0.82). In plasmas of mothers whose levels varied from 18.2 to 50.2% of the mean value of PC donors the assessment of C1-INH by the method of HF fragment activation gave lower results in all instances. The dependence of C1-INH estimation on the amount of PC was demonstrated on deficient plasma with a defined PC level.(ABSTRACT TRUNCATED AT 250 WORDS)
The authors investigated C1-inhibitor (C1-INH) plasma levels in blood collected from mothers during delivery: mothers with a normal pregnancy and a group of mothers who displayed during the perinatal period direct or indirect signs of infectious disease. Both groups, as compared with a group of healthy donors, had low C1-INH levels. The neonates were divided into two groups (normal children and children with perinatal risk of infection) with sub-groups of mature full-term neonates (38-41 weeks of gestation) and premature infants (29-36 weeks of gestation). In the group of normal infants the neonates had on average somewhat lower C1-INH levels, as compared with healthy donors, in premature neonates of this group the lowest mean C1-INH level was recorded. In this group the authors observed a correlation between the inhibitor level and the gestation period. The results of C1-INH assessment in the group of neonates with a perinatal risk of infection were different. In premature neonates a higher average C1-INH level was observed than in mature neonates and the relationship between the C1-INH level and the gestation period was a linear negative regression. The postnatal increase of C1-INH levels on the 1st to 5th day was more rapid in premature neonates of both groups.
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The authors present values of plasma amino acid concentrations assessed on an automatic analyzer in a group of 12 mature neonates whose early and late post-partum adaptation and subsequent psychosomatic development followed-up to the age of 18 months was normal. The amino acids were assessed at the time of delivery, during the maximal weight loss of the infant after the third day and the last estimation was made before discharge from the maternity hospital when the body weight curves of all infants had a rising trend. None of the infants had neonatal jaundice and all were discharged fully breastfed.
ECMO is a therapeutic method which markedly improved the prognosis of premature or near term infants with severe cardiorespiratory insufficiency where conventional intensive care, incl. pulmonary ventilation and medicamentous support of the circulation did not help. It is method which needs the necessary technical equipment, perfect laboratory facilities and well trained teamwork. It is associated with risks which are not negligible, clearly defined indications as well as contraindications. The programme of ECMO, when introduced, should be regional and departments which use it should be in the area of large university hospitals. Despite the considerable costs associated with establishment of a therapeutic ECMO unit, it pays, as in the most threatened group of neonates it shortens the period these infants spend at the intensive care unit and reduces their mortality rate and severe forms of late postasphyctic morbidity.
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The authors assessed plasma prekallikrein (PK) after its conversion into the active enzyme kallikrein from the rate of breakdown of the specific chromogenic substrate NO-Pro-Pre-Arg-pNA. Activation of PK was achieved by the parallel contact method, using dextran sulphate (DS) and by direct activation by the Hageman's factor fragment (HFf). Contact activation assumes the presence of Hageman's factor (HF) and high molecular kininogen (HMW-K) in plasma. Both methods of activation and x = 0,451 +/- 0.146 U/ml in HFf activation). The mean PK value in neonates assessed by activation of DS was lower [mean = 0.105 +/- 0.068 U/ml] than the value assessed by activation of HFf [mean = 0.175 +/- 0.072 U/ml]. In adults the PK values varied at a significantly higher level, the results being higher when HFf was used as activator [mean = 0.346 +/- 0.087 U/ml in DS activation and mean = 0.451 +/- 0.146 U/ml in HFf activation]. The increase of mean values of PK assessed in umbilical blood and on the 3rd and 5th day after delivery was more marked in direct HFf activation. The correlation coefficient of both ways of assessment in neonates was r = 0.79, in the group of adults there was a close correlation r = 0.92. The lower correlation in neonates can be explained by the low level of co-factors, in particular HMW-K, necessary for complete activation of PK by the contact method. In some neonates the PK value assessed by DS expresses only the total activating plasma capacity and not the actual PK level.
The authors give an account of 190 premature infants they treated in 1956-1988, suffering from retinopathy of prematurity--ROP, and for prolonged subsequent periods. As the head of the team followed up all the children, there is an integrated view of the problem. The birth weight of the infants was 640 g--1,900 g. From the total number 76.8% infants had a birth weight of 1,500 g or less, 13.7% had a birthweight of 1,000 g or less. Evidence of the increasing rate is provided by the number of patients treated since birth at the department for premature and pathological infants FNM as well as by the number of children admitted from other departments after development of ROP. In 1956-1970, i. e. in 15 years, the authors looked after 34 patients, in 1971-1988, i. e. in 18 years there were 156 children with ROP. In 1956-70 cases of ROP predominated which developed as a result of absolute or relative hypoxia. They were successfully treated by individually adjusted and carefully controlled oxygen therapy (6.9% blind children). In 1971-1975 the possibility to use this therapy declined briskly because after introduction of modern medical technique the number of findings suggesting a hyperoxic insult increased. At that time the results deteriorated greatly (50% blind children). In 1976-1980 the results were favourably influenced by individual dosage of oxygen therapy in all infants, based on regular monitoring of blood gases (10.5% blind children).(ABSTRACT TRUNCATED AT 250 WORDS)
The authors give an account on cryotherapy of retinopathies in the premature--130 eyes of 93 children treated during 1984-1988. Almost in all children cryocoagulation was made, using a transconjunctival approach, in the avascular periphery of the retina under local instillation anaesthesia. Twenty-eight eyes were coagulated already in stage 2 of the proliferative phase (along with the other more severely affected eye), the results being very satisfactory. In this stage, however, spontaneous regression cannot be ruled out. This is the reason why only 102 eyes were evaluated in detail, i.e. those coagulated in stage 3a and the latter were compared with findings in 90 eyes equally affected where cryocoagulation was not performed. In the group after coagulation 51% of the eyes had findings in stage I and II of the cicatricial phase with good and very good vision, in 17.6% the final finding is stage III with vision in the zone of visual debility and 31.4% of the eyes with findings stage IV and V are blind. In the group without coagulation there were 4.4% eyes in stage I and II, 28.9% eyes in stage III and 66.7% in stages IV and V. In eyes after coagulation the percentage of adverse results (31.4%) is by one half lower than in untreated eyes (66.7%).
During a 24-hour interval, examination was carried out of 5 full-term and 4 preterm newborns in whom no disturbance of postnatal adaptation was found. The newborns received parenteral nutrition using infusates containing 20% Intralipid during 7 hours on the average. The mean daily dose of Intralipid was 1.2 g/kg, infusion rate was 0.17 g/kg/h. The concentration of FFA (n = 9) and ABC/Bi was examined three times in the course of 24 hours, and that prior to Intralipid administration, after one-hour infusion, and approximately 17 hours after the end of infusion. Before infusion and 24 hours after the first collection, blood bilirubin and glucose concentrations, and the values of pH, pCO2 and BE (= 9) were examined. One hour after the start of Intralipid infusion the mean FFA concentration was reduced and decreased again during the following 23 hours. The differences were mostly insignificant. One hour after the start of infusion the mean value of the ABC/Bi ratio decreased insignificantly, but returned to the initial value by the end of the follow-up period (24 hours). The mean concentration of bilirubin and blood glucose and the values of pH, pCO2 and BE did not change significantly. It may be reasonably assumed, that in newborns showing normal postnatal adaptation in the first days of life, the administration of 20% Intralipid (as parenteral nutrition) exerts no substantial effect on the plasma FFA concentration and ABC/Bi ratio in the course of 24 hours. General principles for the indication of parenteral Intralipid administration to the newborn are given.
The first part of the study gives data on the FFA concentrations, glycaemia and energy quotient in newborns with uncomplicated postnatal adaptation in the first 2 weeks of life. The study was carried out in a group of 69 full-term and 69 pre-term infants at the age of 24, 48, 72, 96 hours and 7 and 14 days. Although it is not the case of consecutive values of FFA concentrations in plasma, a certain developmental trend can be suggested. This is analogous in both groups with the only difference that in pre-term infants FFA culminate and decrease earlier (pre-term 48-72 hours, full-term infants 72-96 hours). The study shows that, in pre-term and full-term infants with satisfactory postnatal adaptation and above nutrition, stabilization of glucose-lipid metabolism occurs on the 3rd and 4th day after birth, respectively. In pre-term infants supplementary nutrition by the glucose system (glucose and amino acids) had a favourable effect. The second part of the study assesses the potential risk of increasing plasma FFA concentration for the separation of bilirubin from albumin binding. The means plasma FFA concentrations reached 25-48 and 49-72 hours after birth had no significant effect on the BCA/Bi ratio and, therefore, they are not dangerous as regards the possibility of displacing bilirubin from albumin binding.
An epidemiological analysis of 3427 hospitalized neonates at four Prague intensive care and intermediary care units in 1980-1984 revealed that of the total neonatal risk morbidity, 5.6%, the greatest ratio is accounted for by non-inflammatory respiratory diseases, 3.3%, followed by infections, 1.5%, and serious congenital defects, 0.7%. The incidence of the above groups is higher in Prague, as compared with Scandinavian countries. The lethality of inflammatory diseases and serious congenital defects is the same, in the group of non-inflammatory disease it is markedly higher in particular in the sub-group of pulmonary maladaptation--early asphyctic syndrome. The perspective of reduction of neonatal mortality calls in particular for a reduced incidence of risk morbidity and better care of critically ill neonates.
The authors refer in their paper to previous discussions on methodological problems associated with the application of Doppler continuous ultrasonography in neonatological practice. The methodological investigation was made in a group of twelve neonates with a mean birth weight of 2028 g and gestational age of 33.3 weeks. All were examined at the age of three weeks when the postpartum adaptation is already completed and the clinical condition is stabilized. After perfect mastering of the technique of measurement, the authors found that the mean error of assessment of PI on the internal carotid artery was 3.6%, on its siphon 2.7% and on the anterior cerebral artery 2.7%. The mean error of measurement for MVF on the same arteries was 7.7%, 13.7% and 6.1% resp. The greatest error was for EDFV on the internal carotid artery 11.7% on its siphon 15.8% and on the anterior cerebral artery 6.1%. The smallest mean error of assessment of all three parameters was on the anterior cerebral artery, the greatest error on the siphon of the internal carotid artery. On the investigated arteries no significant lateral difference was recorded. The mean values of PI, MFV and EDFV have a declining trend in the direction towards the periphery, i.e. in the direction from the internal carotid artery to the anterior cerebral artery. These trends were also confirmed in individual children. The authors assume that the method of continuous Doppler ultrasonography is despite limitations, inherent to its nature, suited for use in neonatological practice.