PaO2/FiO2 Ratio as Predictor of Mortality in Neonates with Meconium Aspiration Syndrome.

OBJECTIVES: Partial arterial pressure of oxygen/fraction of oxygen in inspired air (PaO2/FiO2) ratio has been used as a predictor of outcome in some neonatal conditions, but has not been used in meconium aspiration syndrome (MAS). This study was conducted with the objective to study if the PaO2/FiO2 ratio of < 200 at 6, 12, and 24 hours of life can predict mortality in neonates with MAS. STUDY DESIGN: Two hundred neonates with MAS were included in the study. PaO2/FiO2 ratio was calculated at 6, 12, and 24 hours of life. Sensitivity, specificity, predictive values, and likelihood ratio at cut-off < 200 to predict mortality was calculated. RESULTS: PaO2/FiO2 ratio at cut-off of < 200 was found to predict mortality in neonates with MAS with 94.1% sensitivity and 96.6% specificity. It was also able to predict development of severe MAS. CONCLUSION: PaO2/FiO2 at < 200 can predict all-cause mortality in neonates with MAS. It can be used as vital tool in identifying newborns at high risk, thus helping in focused care.

Correlations of Enzyme Levels at Birth in Stressed Neonates with Short-Term Outcomes.

INTRODUCTION: Multi-organ injury causes leakage of several intracellular enzymes into the circulation. We evaluated the correlation between the serum-leaked intracellular enzyme levels at the beginning of treatment and the outcome in perinatally stressed neonates. MATERIALS AND METHODS: We retrospectively studied neonates whose 1 minute Apgar score was < 7. We collected initial venous blood sample data, including aspartate transaminase (AST), alanine transaminase (ALT), lactate dehydrogenase (LDH), and creatine kinase (CK) levels, and correlated these with patient short-term outcomes. RESULTS: Of 60 neonates, nine patients were treated with therapeutic hypothermia, and 32 needed mechanical ventilation. The therapeutic hypothermia group showed significantly larger base deficit, and higher lactate, AST, ALT, LDH, and CK (all p < 0.01). The duration of mechanical ventilation significantly correlated with AST, ALT, LDH, and CK levels (all p < 0.01). CONCLUSION: Initial enzyme levels are useful for predicting the duration of mechanical ventilation in stressed neonates.

Activation of Toll-like receptors in meconium aspiration syndrome.

OBJECTIVE: Meconium aspiration syndrome (MAS) is a common cause of neonatal morbidity and mortality. Incomplete understanding of the pathogenesis of MAS has hindered the development of specific therapies. We hypothesized that activation of Toll-like receptors (TLRs) might play a role in the pathogenesis of MAS. The present study evaluated the expression of TLR 1, 4, 7, 8 and 9 in neonates with MAS. STUDY DESIGN: The study included 39 neonates with MAS and 17 healthy gestational age-matched neonates as controls. Neonates with maternal chorioamnionitis, perinatal asphyxia, sepsis and congenital malformations were excluded. Good-quality total RNA from umbilical cord blood was reverse transcribed to prepare cDNA using Bio-Rad reverse transcription kit. This cDNA was used to study the expression status of TLR 1, 4, 7, 8 and 9 by real-time quantitative polymerase chain reaction. RESULTS: Compared with controls, TLR1 and TLR4 were highly expressed, TLR9 was moderately expressed, TLR7 was weakly expressed and TLR8 expression was neutral in neonates with MAS. Within the MAS group, no difference in TLR expression was observed with respect to consistency of meconium, severity of the disease, oxygenation index and outcome. CONCLUSION: There is activation of TLRs in neonates with MAS. We speculate that these TLRs probably act as endogenous ligands for various components of meconium that initiate the inflammatory cascade of MAS and contribute to its pathogenesis.

Procalcitonin as Predictor of Bacterial Infection in Meconium Aspiration Syndrome.

BACKGROUND: There is a lack of definite consensus on indications for initiating antibiotics in neonates with meconium aspiration syndrome (MAS), instigating researchers to search for a biomarker that can help differentiate MAS from MAS with bacterial infection. OBJECTIVE: Our primary objective was to compare serum procalcitonin (PCT) levels in full-term vigorous neonates having MAS with or without bacterial infection. MATERIALS AND METHODS: Seventy term vigorous neonates with diagnosis of MAS were enrolled. Blood samples were taken for sepsis screen, C-reactive protein (CRP), PCT, and blood culture at 6 ± 2 hours of respiratory distress. Neonates were categorized into group 1 (MAS without bacterial infection) and group 2 (MAS with bacterial infection) based on blood culture. The duration of our study was 18 months. RESULTS: Mean ± standard deviation PCT level was 2.52 ± 3.99 in group 1 and 2.71 ± 4.22 in group 2, which was comparable. At cutoff of 0.1 ng/mL, PCT had a sensitivity of 90% and specificity of 8% in detecting bacterial infection. Mean total leukocyte count, absolute neutrophil count, immature to total leucocyte ratio, microerythrocyte sedimentation rate, and CRP were comparable. CONCLUSION: Though PCT is an early and reliable marker of neonatal infection, the levels were increased in neonates with MAS irrespective of the presence of bacterial infection.

Changes in thyroid hormone concentrations during neonatal extracorporeal membrane oxygenation.

OBJECTIVE: Thyroid hormone concentrations can be disturbed during critical illness. Our aim was to determine changes in thyroid hormone concentrations during neonatal extracorporeal membrane oxygenation (ECMO). STUDY DESIGN: We included 21 ECMO-treated neonates. Age-specific s.d. scores (SDS) of free and total thyroxine (FT4; TT4), reverse and total triiodothyronine (rT3; TT3), thyroid-stimulating hormone (TSH) and thyroxine-binding globulin (TBG) were determined at six fixed time-points. Data were analyzed using general linear models. RESULTS: At baseline, mean SDS FT4 (-0.78, 95% CI: -1.37 to -0.19), TT4 (-1.97, 95% CI: -2.76 to -1.18), TT3 (-0.88, 95% CI: -1.13 to -0.63), TSH (-2.14, 95% CI: -2.93 to -1.35) and TBG (-3.52, 95% CI: -4.55 to -2.50) were low with high mean SDS rT3 (0.53, 95% CI: 0.28 to 0.78). One hour after start ECMO, TT4, TSH and TBG had further declined; 12 h after start ECMO TT3 had declined (all P<0.05). After this decline, mean SDS TSH increased to the baseline level 12 h after start ECMO (-2.50, 95% CI: -3.22 to -1.79), and was higher than baseline 48 h after start ECMO (-0.56, 95% CI: -1.29 to 0.17). This TSH increase was followed by increases in TT4 and TT3. FT4 remained constant within the normal range during ECMO. CONCLUSIONS: Thyroid hormone concentrations before ECMO were suggestive of non-thyroidal illness syndrome (NTIS). During ECMO, increases in TSH, TT4 and TT3 after an initial decline possibly reflect spontaneous restoration of the hypothalamic-pituitary-thyroid axis. FT4 remained constant within the normal range. This suggests that thyroxine therapy is not required during ECMO.

Should fetal scalp blood sampling be performed in the case of meconium-stained amniotic fluid?

OBJECTIVE: To investigate the effect of using fetal scalp blood sampling on the risk of neonatal respiratory distress syndrome (NRDS) with meconium-stained amniotic fluid (MSAF). METHODS: Prospective data collection with regard to MSAF during labor for low-risk term cephalic singleton live birth from 2012 to 2014. Maternal, obstetric and neonatal data were compared according to the occurrence of respiratory distress syndrome (RDS group) or not (no RDS group). RESULTS: Of 515 newborns born through MSAF, 46 experienced RDS and from them 10 experienced meconium aspiration syndrome. No difference was observed according to maternal characteristic, abnormal fetal heart rate tracing pattern irrespective of its category and cesarean rate. Apgar at one minute was lower in the group RDS (7.6 versus 8.5, p < 0.05). The mean umbilical artery pH values did not differ between the two groups. Significant difference between newborns with and without RDS in terms of fetal scalp lactate sampling during the labor (71.1% versus 55.1%, p < 0.05), and neonatal care unit (NCU) admissions (22.8% versus 10.8%, p < 0.05). Secondary rather than primary meconium was associated with RDS when performing fetal scalp blood assessment (p < 0.05). A significant correlation between RDS, fetal scalp blood assessment and MSAF diagnosed during the first stage of labor (after spontaneous rupture of membranes or at amniotomy) was found. CONCLUSION: In case of MSAF, fetal scalp blood sampling did not reduce the risk of RDS.

Effect of Ventilation Support on Oxidative Stress and Ischemia-Modified Albumin in Neonates.

BACKGROUND AND OBJECTIVE: Mechanical ventilation (MV) can induce oxidative stress, which plays a critical role in pulmonary injury in intubated neonates. Ischemia-modified albumin (IMA)-a variant of human serum albumin-is a novel biomarker of myocardial ischemia that occurs due to reactive oxygen species during ischemic insult. This study aimed to investigate IMA production due to oxidative stress induced during MV in neonates. MATERIALS AND METHODS: This study included 17 neonates that were ventilated using synchronized intermittent mechanical ventilation (SIMV; SIMV group) and 20 neonates ventilated using continuous positive airway pressure (CPAP; CPAP group). Blood samples were collected from each neonate during ventilation support and following cessation of ventilation support. Total antioxidant capacity (TAC) and total oxidant status (TOS) were measured using the Erel method. IMA was measured via an enzyme-linked immunosorbent assay kit (Cusabio Biotech Co., Ltd., Wuhan, China). The oxidant stress index (OSI) was calculated as OSI = TOS/TAC. Statistical analysis was performed using SPSS v.18.0 (SPSS Inc., Chicago, IL) for Windows. RESULTS: Among the neonates included in the study, mean gestational age was 34.7 ± 3.8 weeks, mean birth weight was 2,553 ± 904 g, and 54% were premature. There were not any significant differences in mean gestational age or birth weight between the SIMV and CPAP groups. Among the neonates in both the groups, mean IMA, TOS, and OSI levels were significantly higher during ventilation support (102.2 ± 9.3 IU mL(-1), 15.5 ± 1.3 µmol H2O2 equivalent L(-1), and 0.85 ± 0.22 arbitrary units [ABU], respectively), as compared with following cessation of ventilation support (82.9 ± 11.9 IU mL(-1), 13.4 ± 1.3 µmol H2O2 equivalent L(-1), and 0.64 ± 0.14 ABU, respectively) (p = 0.001). Among all the neonates in the study, mean TAC was significantly lower during ventilation support than the postventilation support (1.82 ± 0.28 mmol 6-hydroxy-2,5,7,8-tetramethylchroman-2-carboxylic acid [Trolox] equivalent L(-1) vs. 2.16 ± 0.31 mmol Trolox equivalent L(-1)) (p = 0.001). There were no significant differences in mean TAC, OSI, or IMA levels between the SIMV and CPAP groups. The mean TOS level during ventilation support and the mean difference in TOS between during and postventilation support was significantly greater in the CPAP group than in the SIMV group. There were no significant relationships between the mean TOS, TAC, OSI, or IMA levels, and gestational age of the neonates. CONCLUSION: SIMV and CPAP activated the oxidative stress and increased the IMA level in neonates; therefore, measurement of IMA and oxidant markers may be useful in the follow-up of lung injury in neonates due to ventilation support. Additional prospective studies are needed to compare the effects of various ventilation methods on oxidative stress and the IMA level in neonates.

Oxygen saturation index and severity of hypoxic respiratory failure.

BACKGROUND: The oxygenation index (OI = mean airway pressure, MAP × FiO2 × 100 : PaO2) is used to assess the severity of hypoxic respiratory failure (HRF) and persistent pulmonary hypertension of the newborn (PPHN). An indwelling arterial line or arterial punctures are necessary to obtain PaO2 for the calculation of OI. Oxygenation can be continuously and noninvasively assessed using pulse oximetry. The use of the oxygen saturation index (OSI = MAP × FiO2 × 100 : SpO2) can be an alternate method of assessing the severity of HRF. OBJECTIVE: To evaluate the correlation between OSI and OI in the following: (1) neonates with HRF and (2) a lamb model of meconium aspiration syndrome. METHODS: Human neonates: a retrospective chart review of 74 ventilated late preterm/term neonates with indwelling arterial access and SpO2 values in the first 24 h of life was conducted. OSI and OI were calculated and correlated. Lamb model: arterial blood gases were drawn and preductal SpO2 was documented in 40 term newborn lambs with asphyxia and meconium aspiration. OI and OSI were calculated and correlated with pulmonary vascular resistance (PVR). RESULTS: Mean values of OSI and OI showed a correlation coefficient of 0.952 in neonates (mean value of 308 observations in 74 neonates) and 0.948 in lambs (mean value of 743 observations in 40 lambs). In lambs, with increasing PVR, there was a decrease in OI and OSI. CONCLUSION: OSI correlates significantly with OI in infants with HRF. This noninvasive measure may be used to assess the severity of HRF and PPHN in neonates without arterial access.

Cardiovascular effects of N-acetylcysteine in meconium-induced acute lung injury.

Anti-inflammatory drugs are increasingly used for treatment of neonatal meconium aspiration syndrome (MAS), but their adverse effects are poorly known. Therefore, the aim of this study was to evaluate the effects of the antioxidant N-acetylcysteine on cardiovascular parameters in an animal model of MAS. Oxygen-ventilated rabbits were intratracheally instilled 4 mL/kg of meconium suspension (25 mg/mL) or saline. Thirty minutes later, meconium-instilled animals were given N-acetylcysteine (10 mg/kg, i.v.) or the same volume of saline. Changes in cardiovascular parameters (blood pressure, heart rate, and heart rate variability) were recorded over a 5-min course of solution administration, over 5 min after its end, and then hourly for 5 h. Oxidation markers (thiobarbituric acid-reactive substances (TBARS) and total antioxidant status) and aldosterone, as a non-specific marker of cardiovascular injury, were determined in plasma. Meconium instillation did not evoke any significant cardiovascular changes, but induced oxidative stress and elevated plasma aldosterone. N-acetylcysteine significantly reduced the mentioned markers of injury. However, its administration was associated with short-term increases in blood pressure and in several parameters of heart rate variability. Considering these effects of N-acetylcysteine, its intravenous administration in newborns with MAS should be carefully monitored.

Short-term cardiovascular effects of selective phosphodiesterase 3 inhibitor olprinone versus non-selective phosphodiesterase inhibitor aminophylline in a meconium-induced acute lung injury.

Various anti-inflammatory drugs have been used for treatment of neonatal meconium aspiration syndrome (MAS). As their adverse effects are poorly described, this study compared effects of selective phosphodiesterase (PDE) 3 inhibitor olprinone and non-selective PDE inhibitor aminophylline on cardiovascular parameters in animal model of MAS. Oxygen-ventilated rabbits were intratracheally instilled 4 mL/kg of meconium (25 mg/mL) or saline. Thirty minutes later, meconium-instilled animals were intravenously given olprinone (0.2 mg/kg) at a single dose at 0.5 h after meconium instillation, or aminophylline (2.0 mg/kg) at two doses at 0.5 and 2.5 h after meconium instillation, or were left without treatment. Cardiovascular changes were evaluated within 5 min of administration and 5 min after finishing the administration. Furthermore, respiratory and cardiovascular parameters were measured within 5 hours following treatment delivery. Oxidation markers (thiobarbituric acid-reactive substances (TBARS), and total antioxidant status) and markers of cardiovascular injury (aldosterone, gamma-glutamyltransferase (GGT), aspartate aminotransferase (AST), and alanine aminotransferase (ALT)) were determined in the plasma. Meconium instillation induced acute lung injury associated with oxidative stress, elevated aldosterone, and slightly increased GGT and AST levels. Both aminophylline and olprinone improved lung functions and reduced oxidation stress. However, the PDE inhibitors acutely increased blood pressure and heart rate, whereas heart rate variability remained higher till the end of experiment and correlated well with markers of cardiovascular injury. Considering that systemic administration of olprinone and aminophylline was accompanied by acute cardiovascular changes in the meconium-instilled animals, use of PDE inhibitors in the newborns with MAS should be carefully monitored.

Cord blood S100B levels in low-risk term pregnancies with meconium-stained amniotic fluid.

OBJECTIVE: The aim of this study was to compare cord blood S100B levels and cord blood gas parameters of term infants with meconium-stained amniotic fluid (MSAF) to those infants with clear amniotic fluid. METHODS: Term pregnant women at an active phase of labor and having MSAF were defined as the study group (n = 35) and pregnant women with clear amniotic fluid, and matched for age, parity, and gestational age were defined as the control group (n = 35). Cord blood S100B levels and gas parameters were measured. RESULTS: LogS100B values of study and control groups were 2.40 ± 0.21 and 2.43 ± 0.29 pg/ml, respectively. The difference was not statistically significant (p = 0.675). LogS100B levels slightly increased as meconium thickened. (2.32 ± 0.16, 2.41 ± 0.17, and 2.44 ± 0.28 pg/ml, respectively). However, no difference was found between groups (p = 0.438). Moreover, the study group had a statistically lower HCO(3) level (21.80 vs 23.60 mmol/l) and a higher rate of base deficit (4.85 vs 3.25 mmol/l) than the control group. However, median HCO(3) and base deficit values were within normal limits in both groups. CONCLUSION: The present study showed that cord blood S100B levels of infants born through MSAF were not different from those with clear amniotic fluid. This finding suggests that MSAF, regardless of its thickness, may not be related to brain damage in low risk term pregnancies.

Anti-inflammatory treatment in dysfunction of pulmonary surfactant in meconium-induced acute lung injury.

Inflammation, oxidation, lung edema, and other factors participate in surfactant dysfunction in meconium aspiration syndrome (MAS). Therefore, we hypothesized that anti-inflammatory treatment may reverse surfactant dysfunction in the MAS model. Oxygen-ventilated rabbits were given meconium intratracheally (25 mg/ml, 4 ml/kg; Mec) or saline (Sal). Thirty minutes later, meconium-instilled animals were treated by glucocorticoids budesonide (0.25 mg/kg, i.t.) and dexamethasone (0.5 mg/kg, i.v.), or phosphodiesterase inhibitors aminophylline (2 mg/kg, i.v.) and olprinone (0.2 mg/kg, i.v.), or the antioxidant N-acetylcysteine (10 mg/kg, i.v.). Healthy, non-ventilated animals served as controls (Con). At the end of experiments, left lung was lavaged and a differential leukocyte count in sediment was estimated. The supernatant of lavage fluid was adjusted to a concentration of 0.5 mg phospholipids/ml. Surfactant quality was evaluated by capillary surfactometer and expressed by initial pressure and the time of capillary patency. The right lung was used to determine lung edema by wet/dry (W/D) weight ratio. Total antioxidant status (TAS) in blood plasma was evaluated. W/D ratio increased and capillary patency time shortened significantly, whereas the initial pressure increased and TAS decreased insignificantly in Sal vs. Con groups. Meconium instillation potentiated edema formation and neutrophil influx into the lungs, reduced capillary patency and TAS, and decreased the surfactant quality compared with both Sal and Con groups (p > 0.05). Each of the anti-inflammatory agents reduced lung edema and neutrophil influx into the lung and partly reversed surfactant dysfunction in the MAS model, with a superior effect observed after glucocorticoids and the antioxidant N-acetylcysteine.

Meconium-stained amniotic fluid and hypoglycemia among term newborn infants.

To evaluate whether meconium-stained amniotic fluid (MSAF) is a risk factor for neonatal hypoglycemia. Retrospective recording of medical charts of full-term infants born following observation of meconium-stained amniotic fluid to examine glucose levels in the first hours of life. Out of 803 infants of the study group, 68 (8.5%) had glucose levels lower than 47 mg/dl. Most (6.7%) had mild hypoglycemia, and 14 (1.8%) had moderate or severe hypoglycemia (1.4% and 0.4% respectively). No infant developed clinical signs clearly related to hypoglycemia. Low-risk infants born following meconium-stained amniotic fluid are not at increased risk for neonatal hypoglycemia.

Urotensin-II contributes to pulmonary vasoconstriction in a perinatal model of persistent pulmonary hypertension of the newborn secondary to meconium aspiration syndrome.

Meconium aspiration syndrome (MAS) disrupts perinatal decreases in pulmonary vascular resistance (PVR) and is the commonest cause of neonatal pulmonary hypertension. The contribution of the potent vasoactive agent urotensin-II (U-II), in the pathophysiology of this condition, is unknown. In a new perinatal model of MAS, we combined measurement of circulating U-II levels with U-II receptor blockade studies. Nineteen anesthetized lambs were instrumented then randomly allocated to the following groups: 1) control (n = 5), 2) control plus specific U-II receptor blockade with palosuran (n = 5), 3) tracheal instillation of meconium (n = 5), 4) meconium instillation plus palosuran (n = 4). Hemodynamics, PVR, and plasma U-II were measured for 6 h after delivery. After birth in controls, U-II increased (p < 0.05), and PVR fell (p = 0.01) and this fall was prevented by U-II receptor blockade. By contrast, meconium lambs displayed a greater rise in U-II levels (p < 0.05 versus control) with an increase in PVR (p < 0.005) that was attenuated by U-II receptor blockade (p < 0.001). These findings suggest that U-II normally acts as a pulmonary vasodilator after birth, but in the presence of MAS, it assumes a vasoconstrictor role. U-II receptor blockade also improves pulmonary hemodynamics in this model.

Phospholipase A2 in meconium-induced lung injury.

Although the triggering mechanisms of tissue inflammation and injury in meconium-contaminated lungs are still unclear, there is increasing evidence to suggest a central role for phospholipase A(2)'s (PLA(2)). In fact, elevated PLA(2) activities together with high enzyme concentrations, especially the amount of pancreatic (group I) secretory PLA(2) (PLA(2)-I), have been detected in human meconium and in meconium-contaminated lungs. Recent data from our laboratory further indicate that human pancreatic PLA(2), introduced in high amounts within aspirated particulate meconium, is a potent inducer of lung tissue inflammatory injury. Our finding of elevated human PLA(2)-I concentrations in plasma during the first hours after intratracheal meconium administration in newborn piglets further suggests that intrapulmonary aspiration of meconium could also have systemic inflammatory and injurious effects. This, however, remains to be studied in further detail.

Serum cytokine and chemokine profiles in neonates with meconium aspiration syndrome.

OBJECTIVES: Various inflammatory cytokines and chemokines are thought to be associated with the pathophysiology of meconium aspiration syndrome. To clarify any such association, we compared various serum cytokine and chemokine profiles in patients with and without meconium aspiration syndrome. PATIENTS AND METHODS: Using a highly sensitive fluorescence microsphere method, 17 types of cytokines and chemokines in sera were measured in 11 neonatal patients with meconium aspiration syndrome, 16 neonatal patients without meconium aspiration syndrome, and 9 healthy children. RESULTS: The concentrations of 8 types of proinflammatory cytokines and chemokines were significantly higher in the meconium aspiration syndrome group than in healthy controls: interleukin-1beta, interleukin-6, interleukin-8, granulocyte-macrophage colony-stimulating factor, granulocyte colony-stimulating factor, interferon-gamma, macrophage inflammatory protein-1beta, and tumor necrosis factor-alpha. Six types of proinflammatory cytokines and chemokines were significantly higher in the meconium aspiration syndrome group than in the nonmeconium aspiration syndrome group: interleukin-6, interleukin-8, granulocyte-macrophage colony-stimulating factor, granulocyte colony-stimulating factor, interferon-gamma, and tumor necrosis factor-alpha. Serum concentrations of interleukin-10 (anti-inflammatory cytokine) in the meconium aspiration syndrome group were higher than those in both the nonmeconium aspiration syndrome group and healthy children group (P = .007 and 0.001, respectively). CONCLUSIONS: Most types of proinflammatory cytokines and chemokines in sera of neonates with meconium aspiration syndrome were higher than those without meconium aspiration syndrome, giving support to the suggestion that elevated levels are associated with the pathogenesis of meconium aspiration syndrome.

Serum endothelin-1 and transforming growth factor-beta levels in the newborns with respiratory distress.

The purpose of this present study was to evaluate the serum levels of ET-1 and TGF-beta in the newborns with respiratory distress. In this study, newborns with respiratory distress hospitalized into the Newborn Intensive Care Unit were included. The highest values of ET-1 and TGF-beta were obtained from newborns with diagnosis as meconium aspiration syndrome (5.70 +/- 5.87 pg/mL and 3.75 +/- 1.94 pg/mL, resp) in the sample obtained in the first six hours after birth, and these are statistically different from control group (P < .05). Also, same results were obtained for newborns with respiratory distress syndrome (3.37 +/- 1.59 pg/mL and 2.05 +/- 0.98 pg/mL, resp). After oxygen treatment, ET-1 values obtained in the first six hours of life were decreased regularly in the following days (P < .05). In the differentiating diagnosis of the respiratory distress of newborns, the investigation of ET-1 and TGF-beta levels is meaningful. The ET-1 levels investigated in the first six hours is more useful in determining the prognosis, and repeating ET-1 levels in the following days is more meaningful to determine clinical response.

Serum KL-6 level in newborns with meconium aspiration syndrome.

BACKGROUND: It has been reported that serum KL-6 increases in babies with progressing chronic lung disease (CLD). However, there have been few reports assessing KL-6 in meconium aspiration syndrome (MAS). KL-6 was measured in neonates with respiratory diseases including MAS. METHODS: Thirty-eight neonates with respiratory disease were enrolled in the study. These patients were classified into three groups, 14 patients with respiratory distress syndrome (RDS), 14 with MAS, and 10 with transient tachypnea of the newborn (TTN). The control group consisted of 12 healthy neonates. KL-6 levels were measured 1 day (median) after the birth. In the RDS group, measurement was repeated just prior to 36 weeks' postmenstrual age. RESULTS: The levels of KL-6 were 116 +/- 40 U/mL in the RDS, 281 +/- 138 U/mL in the MAS, and 106 +/- 41 U/mL in the TTN groups. KL-6 levels were significantly higher in the MAS group than in the control group (134 +/- 71 U/mL; P < 0.01). In addition, the levels were significantly higher in those with severe MAS than those with mild MAS (P < 0.05). In patients with RDS, KL-6 increased in patients who developed CLD (P < 0.05), while KL-6 levels did not change in those who did not develop CLD. CONCLUSION: These data confirm the high level of KL-6 in CLD, and suggest that KL-6 is increased in MAS.

The effects of prednisolone and serum malondialdehyde levels in puppies with experimentally induced meconium aspiration syndrome.

The aim of this study was to investigate the effect of different doses of prednisolone in puppies experimentally induced with meconium aspiration syndrome (MAS). Meconium was collected from human babies in the first day of life and was released into the trachea of 11 newborn puppies to induce MAS. Puppies were treated with 2 mg/kg prednisolone (standard dose), 30 mg/kg prednisolone (megadose) or 0.9% saline, all administered intravenously. The study ended 20 h after meconium aspiration and the lungs were then scored for histopathology. Animals not treated with prednisolone deteriorated after 8 h while respiration rate, oxygenation, pH and partial pressure of carbon dioxide values were better in the prednisolone-treated groups. Histopathology scores were better in the treatment groups compared with the control group, with megadose giving the best result. At the end of the study, serum malondialdehyde levels were significantly higher in the megadose prednisolone group compared with the other two groups. In conclusion, we determined that prednisolone reduced physiological and histological changes in puppies with MAS and that a 30 mg/kg dose was more effective than 2 mg/kg.

Endothelin 1 concentrations in infants with meconium stained amniotic fluid.

Plasma endothelin 1 concentrations were determined in infants with meconium stained amniotic fluid. Plasma endothelin 1 concentration in the study group (5.23 pg/ml) was statistically higher than that in the control group (1.12 pg/ml). Cord blood pH and base excess values were significantly lower in infants with meconium stained amniotic fluid when compared with the control group. There was no correlation between endothelin 1 concentrations and pH or base excess values. Results suggest that meconium passage is not a physiological event, even if meconium stained infants appear to be clinically healthy.