Oxygenation and Lung Morphology in a Rabbit Pediatric ARDS- Model under High Peak Pressure Ventilation plus Nitric Oxide and Surfactant Compared with Veno-venous ECMO

The aim of the study is to investigate which of two treatment options of saline lavage induced ARDS in rabbits is better in terms of oxygenation and prevention of barotrauma: combined high peak pressure ventilation with surfactant administration and inhaled nitric oxide or veno-venous ECMO combined with low peak inspiratory pressure ventilation.

Materials and Methods

After saline lavage (10 cc/kg repeated as long as foamy retrieval was observed) two combined therapeutic strategies were examined: ventilation with high inspiratory pressures (35 cm H2O) with additional exogenous surfactant administration (100 mg/kg) and inhaled nitric oxide (10 PPM) (n=5, group 1) and low inspiratory pressure (20 cm H2O) ventilation under veno-venous ECMO support (n=5, group 2). The FiO2 was maintained at 1.0 in both groups. The paO2/FiO2 ratio was calculated in 30 minute intervals for 4 hours. After that the animals were sacrificed and the lungs examined macro- and microscopically. Aeration was described in a semiquantitative method using the alveolar expansion index. Oxygenation in group 1 was significantly better than in group 2, it increased significantly after surfactant but not after additional nitric oxide administration. However, the lungs in group 1 showed severe signs of baro/ergotrauma (Hyaline membranes, air leaks, infiltration of polymorphonuclear (PMN) granulocytes and macrophages, break down of alveolar capillary membranes) after 4 hrs of combined therapy, whereas the lungs in group 2 appeared normal. Adding surfactant and NO to a high tidal volume ventilation improved oxygenation, but did not prevent baro/ergotrauma. Ventilation with low inspiratory pressures combined with ECMO caused little baro/ergotrauma but adequate oxygenation could not be achieved, probably due to anatomical features of the rabbit which do not allow appropriate blood flow within the ECMO-circuit.

Treatment of Severe Non-Neonatal ARDS in Children with Surfactant and Nitric Oxide in a “PRE-ECMO”-Situation

The use of exogenous surfactant and nitric oxide in neonates has reduced the number of infants requiring ECMO. The purpose of this study was to demonstrate whether these two therapeutic options might reduce the number of over 28 days old children with severe ARDS requiring ECMO, without reducing changes of survival and morbidity. Over a 30 month period all non-neonatal ARDS patients transferred to our institution for ECMO evaluation were treated based on a study-algorithm. If they did not fulfill “fast entry criteria” (paO2< 40 for more than 3 hrs.) we first tried different ventilation, vasodilatation, and hemodynamic strategies for max. 4 hrs. (inv. I/E ratio, HFOV, epoprostenol, high doses norepinephrine. If the 01 did not decrease by< 10, 30-280 mg natural surfactant or 1-20 ppm nitric oxide were treatment options depending on the degree of pulmonary hypertension measured by echocardiography and by mixed venous saturation measurements. It was possible to use NO and surfactant sequentially. The patients had different etiologies of ARDS as near drowning, pneumonia, immunosuppression, and sepsis. If their 01 did not decrease by 10 in 8 hrs. ECMO was installed. Nineteen patients were evaluated, 6 improved with conventional therapy, their 01 decreased without a relapse (mean 01 at begin of the study: 38). Six patients improved with surfactant therapy alone (mean 01: 54), 4 patients improved after surfactant and sequential NO-treatment, 3 patients were initially treated with NO, 1 sequentially with surfactant. One patient did not show any benefit from NO or surfactant and was put on ECMO. Three patients died (withdrawal of life support because of severe brain damage caused by the underlying disease). We could not observe any respiratory related failure. No patient had to be discharged on oxygen. A sophisticated treatment algorithm integrating different modern ARDS treatment options can reduce the number of patients requiring ECMO. We speculate however that these options can only be used effectively in centers involved in ARDS treatment quite frequently and that these centers have to provide ECMO as one of their therapeutic tools.

Maternal and Neonatal Outcomes of Preterm Premature Rupture of Membranes before Viability

BACKGROUND

To investigate maternal and neonatal outcomes of previable preterm premature rupture of membranes (PPROM) and compare outcome between previable PPROM before and after 20 weeks of pregnancy, with data from one single center.

PATIENTS

All women with singleton or twin pregnancies, from 2002 through 2011, who presented with PPROM before 24 weeks of gestation.

METHOD

A retrospective cohort study in a university teaching hospital in the Netherlands. Data were analyzed and compared between pregnancies with previable PPROM before and after 20 weeks of pregnancy. Main outcome measures were maternal and neonatal morbidity and mortality.

RESULTS

A total of 160 women (164 fetuses) were included. 90 women (56.2%) developed complications (intra-uterine infection, retained placenta, placental abruption or sepsis). There was no maternal mortality. 68 neonates were admitted after birth. PPHN (64.7%, p=0.001) and contractures (58.8%, p<0.001) occurred significantly more in neonates born after PPROM<20 weeks of pregnancy. Eventually 38.4% of the neonates survived. Neonates born after previable PPROM > 20 weeks had a greater likelihood of being alive at discharge (22.7 vs. 46.9%, p=0.008).

DISCUSSION

This study of previable PPROM shows that more than 50% of the mothers develop one or more complications. Neonates have a high mortality rate, especially neonates born after PPROM<20 weeks of pregnancy. In particular neonates born after PPROM<20 weeks of pregnancy should be watched closely for PPHN and contractures.

CONCLUSION

This large single center study can provide good foundation for counseling parents on previable PPROM, especially the prognosis of PPROM<20 weeks of pregnancy is of additional value.

Management of pulmonary hypertension in neonates with congenital diaphragmatic hernia

Pulmonary hypertension associated with congenital diaphragmatic hernia is still one of the major challenges in neonatal intensive care units. Several relevant pathways in its pathogenesis have been described and studied, but the absence of well-designed randomized controlled trials and the scattered data on the pharmacokinetics and pharmacodynamics of most of the drugs used in these patients hamper progress significantly. This review aims to give an overview of current management strategies in the antenatal and neonatal phase, and provides founded clinical recommendations.

Challenges in non-neonatal extracorporeal membrane oxygenation

This review will address the different challenges for the use of non-neonatal extracorporeal membrane oxygenation (ECMO). It will discuss the available evidence for the use of pediatric ECMO in respiratory and circulatory failure, focusing on indications and contra-indications and choice of ECMO mode. Furthermore we will try to define optimal treatment goals, identify primary outcome parameters and calculate the expected need for non-neonatal ECMO per 1.000.000 inhabitants.

Regenerative therapies in neonatology: clinical perspectives

Regenerative therapy based on stem cells is applied as standard therapy in pediatric oncology. Furthermore, they are frequently used to treat immunodeficiency disorders of infants. For severe neonatal diseases, e. g. hypoxic-ischemic encephalopathy in term neonates or bronchopulmonary dysplasia in preterm infants, animal models have been established. According to some first preclinical results stem cell administration appears as a promising tool to improve the clinical outcome in high-risk infants. Provided the benefit of regenerative therapies can further be evaluated in appropriate preclinical neonate models, carefully controlled clinical trials to assess the significance of regenerative therapies, such as autologous stem cell administration, are indicated.

Prediction of chronic lung disease, survival and need for ECMO therapy in infants with congenital diaphragmatic hernia: additional value of fetal MRI measurements?

INTRODUCTION

The lung-to-head ratio (LHR), measured by ultrasound, and the fetal lung volume (FLV), measured by MRI, are both used to predict survival and need for extra corporeal membrane oxygenation (ECMO) in infants with congenital diaphragmatic hernia (CDH). The aim of this study is to determine whether MRI measurements of the FLV, in addition to standard ultrasound measurements of the LHR, give better prediction of chronic lung disease, mortality by day 28 and need for ECMO.

MATERIALS AND METHODS

Patients with unilateral isolated CDH born between January 2002 and December 2008 were eligible for inclusion. LHR and FLV were expressed as observed-to-expected values (O/E LHR and O/E FLV). Univariate and multivariate analyses were performed. Receiver operating characteristic curves were constructed and areas under the curve (AUC) were calculated to determine predictive values.

RESULTS

90 patients were included in the analysis. Combined measurement of the O/E LHR and O/E FLV gave a slightly better prediction of chronic lung disease (AUC=0.83 and AUC=0.87) and need for ECMO therapy (AUC=0.77 and AUC=0.81) than standard ultrasound measurements of the O/E LHR alone. Combined measurement of the O/E LHR and O/E FLV did not improve prediction of early mortality (AUC=0.90) compared to measurement of the O/E LHR alone (AUC=0.89). An intrathoracal position of the liver was independently associated with a higher risk of early mortality (p<0.001), chronic lung disease (p=0.007) and need for ECMO therapy (p=0.001).

DISCUSSION

Chronic lung disease and need for ECMO therapy are slightly better predicted by combined measurement of the O/E LHR and the O/E FLV. Early mortality is very well predicted by measurement of the O/E LHR alone.

CONCLUSION

Clinical relevance of additional MRI measurements may be debated.

Standardized postnatal management of infants with congenital diaphragmatic hernia in Europe: the CDH EURO Consortium consensus

Congenital diaphragmatic hernia (CDH) is associated with high mortality and morbidity. To date, there are no standardized protocols for the treatment of infants with this anomaly. However, protocols based on the literature and expert opinion might improve outcome. This paper is a consensus statement from the CDH EURO Consortium prepared with the aim of achieving standardized postnatal treatment in European countries. During a consensus meeting between high-volume centers with expertise in the treatment of CDH in Europe (CDH EURO Consortium), the most recent literature on CDH was discussed. Thereafter, 5 experts graded the studies according to the Scottish Intercollegiate Guidelines Network (SIGN) Criteria. Differences in opinion were discussed until full consensus was reached. The final consensus statement, therefore, represents the opinion of all consortium members. Multicenter randomized controlled trials on CDH are lacking. Use of a standardized protocol, however, may contribute to more valid comparisons of patient data in multicenter studies and identification of areas for further research.

Risk factors for chronic lung disease and mortality in newborns with congenital diaphragmatic hernia

BACKGROUND

Congenital diaphragmatic hernia (CDH) is associated with a mortality rate of 10-35% in live-born infants. Moreover, CDH survivors have a substantial risk of developing long-term pulmonary sequelae, such as bronchopulmonary dysplasia (BPD).

OBJECTIVES

This study aims to evaluate risk factors associated with BPD and mortality in neonates with CDH, with particular focus on the initial ventilation mode.

METHODS

Eligible for inclusion were live-born infants with CDH born from 2001 through 2006 at the centers participating in the CDH Study Group. BPD (defined as oxygen dependency at day 30) and/or mortality by day 30 served as the primary endpoint.

RESULTS

A total of 2,078 neonates were included in the analysis. At day 30, 56% of the patients had either died or met the criteria for BPD. In infants who survived until day 30, the prevalence of BPD was 41%. The overall mortality rate was 31%. High-frequency oscillatory ventilation as initial ventilation mode, a right-sided defect, a prenatal diagnosis, a lower Apgar score at 5 min, a cardiac anomaly, a chromosomal anomaly and a lower gestational age were all associated with BPD and/or mortality by day 30.

CONCLUSIONS

Despite improvements in neonatal care, the rates of BPD and early mortality in newborns with CDH are still considerable. Several important risk factors for a worse outcome are reported in this nonrandomized prospective observational study.

Inhibition of phosphodiesterase 4 enhances lung alveolarisation in neonatal mice exposed to hyperoxia

Bronchopulmonary dysplasia (BPD) is characterised by impaired alveolarisation, inflammation and aberrant vascular development. Phosphodiesterase (PDE) inhibitors can influence cell proliferation, antagonise inflammation and restore vascular development and homeostasis, suggesting a therapeutic potential in BPD. The aim of the present study was to investigate PDE expression in the lung of hyperoxia-exposed mice, and to assess the viability of PDE4 as a therapeutic target in BPD. Newborn C57BL/6N mice were exposed to normoxia or 85% oxygen for 28 days. Animal growth and dynamic respiratory compliance were reduced in animals exposed to hyperoxia, paralleled by decreased septation, airspace enlargement and increased septal wall thickness. Changes were evident after 14 days and were more pronounced after 28 days of hyperoxic exposure. At the mRNA level, PDE1A and PDE4A were upregulated while PDE5A was downregulated under hyperoxia. Immunoblotting confirmed these trends in PDE4A and PDE5A at the protein expression level. Treatment with cilomilast (PDE4 inhibitor, 5 mg.kg(-1).day(-1)) between days 14 and 28 significantly decreased the mean intra-alveolar distance, septal wall thickness and total airspace area and improved dynamic lung compliance. Pharmacological inhibition of phosphodiesterase improved lung alveolarisation in hyperoxia-induced bronchopulmonary dysplasia, and thus may offer a new therapeutic modality in the clinical management of bronchopulmonary dysplasia.

Hypoxia-induced intrauterine growth retardation: effects on pulmonary development and surfactant protein transcription

BACKGROUND AND OBJECTIVES

Preterm infants with intrauterine growth retardation (IUGR) reveal an increased risk for the development of acute and chronic pulmonary disorders, i.e. bronchopulmonary dysplasia (BPD). In order to investigate the effect of IUGR on pulmonary development, an easily reproducible animal model for fetal growth restriction has been established using hypoxia as a sole intervention in the last third of pregnancy.

METHODS

Date-mated mice were randomly assigned to either being kept at a fraction of inspired oxygen (FiO2) of 0.10 (hypoxic group) starting at day 14 or under normoxic conditions until day 17.5 of gestation (control group). Variables of somatic growth were assessed and standardized histomorphometric analyses of pulmonary tissue were performed. Expression of surfactant proteins (SP)-A, -B, -C and -D was determined by quantitative rt-PCR as biochemical indicators for lung development and maturation.

RESULTS

Fetuses were delivered preterm at 0.87 of gestation. Those grown under hypoxic conditions revealed significantly lower birth weights (median: 0.69 vs. 0.97 g in controls; p < 0.001), body lengths (median: 17.5 vs. 20.2 mm in controls; p < 0.001) and fronto-occipital diameters (median: 9.4 vs. 10.1 mm in controls; p < 0.001) compared to controls. Histomorphometric analyses were found to be without significant differences between both groups. On the transcriptional level, however, mRNA expression of SP-A, -B and -C but not SP-D could be shown to be significantly reduced in hypoxic fetuses compared to normoxic controls.

CONCLUSIONS

In conclusion, hypoxic conditions from day 14 to 17.5 led to IUGR in preterm mice and to significant alterations of the developing surfactant system. We speculate restricted development of SP gene expression to be a causal factor for the increased risk of acute and chronic pulmonary disorders in preterm infants with IUGR.

Plasma Arginine and Urinary Nitrate and Nitrite Excretion in Bronchopulmonary Dysplasia

The aim of this prospective study was to determine whether preterm infants with bronchopulmonary dysplasia (BPD) and signs of increased pulmonary artery pressure have a deficiency of plasma arginine (ARG) and systemic nitric oxide (NO) synthesis. Plasma amino acid concentrations, Doppler pulmonary systolic time intervals (ratio of acceleration time and ejection time corrected for heart rate: AT/ET(C)) and urinary nitrate and nitrite concentrations were determined at the 28th day postnatal age and at 36 weeks postmenstrual age in 73 preterm infants less than 30 weeks gestational age. The AT/ET(C) ratios were significantly lower in infants with BPD (n = 32) compared to controls. However, total amino acid concentrations, ARG intake as well as plasma ARG concentrations were not different between groups (median (interquartile-range) micromol/l): control: 58 (42.5-75.5) and 54.5 (42-71) at day 28 and 36 weeks; BPD: 54.5 (31.5-70.5) and 43 (35-62), respectively. Urinary nitrate and nitrite concentrations, were not different between groups at day 28, but significantly higher in infants with BPD at 36 weeks (p = 0.014). In conclusion, plasma ARG concentrations and systemic NO synthesis were not deficient in preterm infants with BPD and signs of elevated pulmonary artery pressure.

[Wilson-Mikity syndrome as a cause of respiratory insufficiency of prematurity]

The Wilson-Mikity syndrome is a differential diagnosis of chronic lung disease in the neonate and primarily related to immaturity. It is characterized by the absence of typical clinical and radiological findings of the respiratory distress syndrome (RDS). Infectious causes are being discussed.

Congenital leukaemia after heavy abuse of permethrin during pregnancy

A single case is described of congenital leukaemia with 11q23/MLL rearrangement in a preterm female newborn. Because of arachnophobia, the mother had heavily abused aerosolised permethrin, a widely used household insecticide. Permethrin is considered comparatively safe, but, in view of the mother's history, its potential to induce cleavage of the MLL gene in cell culture was tested. Incubation of the BV173 cell line with 50 micro M permethrin readily induced MLL cleavage.

Lung volume reduction surgery in bronchopulmonary dysplasia

We report on a female preterm infant of 29 wk gestational age, who developed acquired lobar emphysema after prolonged artificial ventilation secondary to respiratory disease syndrome and bronchopulmonary dysplasia. The infant underwent atypical segmentectomy at the age of 12 mo because of life-threatening hypoxaemia with pulmonary hypertension and failure of conservative treatment.

CONCLUSION

Lung volume reduction surgery (LVRS) dramatically improved the respiratory function and resulted in adequate weight gain and psychomotor development. In selected cases LVRS can be an option for lobar emphysema in premature infants with severe bronchopulmonary dysplasia.

Influence of gestational age and intrauterine growth on leptin concentrations in venous cord blood of human newborns

BACKGROUND

The ob gene product leptin is involved in the regulation of body weight and energy expenditure, suggesting a potential role of leptin in embryonal and fetal development and progression of pregnancy. In term infants, leptin concentrations showed a positive correlation with birth weight. We aimed at comparing leptin cord blood levels in AGA (appropriate for gestational age) to SGA (small for gestational age) preterm and term newborns.

PATIENTS AND METHODS

Ninety-seven human newborns, 47 females and 50 males, 33 born at term and 64 born before 36 weeks of gestation, were studied prospectively. Leptin concentrations in venous cord blood were determined using a specific RIA (radioimmunoassay).

RESULTS

In term newborns, mean gestational age (GA) was 39 weeks (wk) (+/- 0.7 wk) and mean birth weight (BW) was 3316 g (+/- 473 g); in preterm newborns (n = 64), mean GA was 30 wk (+/- 5.0 wk) and mean BW was 1398 g (+/- 505 g). Mean standard deviation score of birth weight (BW SDS) was calculated as - 0.47. Mean leptin concentrations in term newborns differed significantly from those in preterm newborns (9.21 +/- 2.63 ng/ml vs. 1.58 +/- 0.88 ng/ml; p < 0.0001). In preterm and term infants, leptin concentrations showed a linear correlation with BW (r = 0.46; p < 0.0001) and GA (r = 0.48; p < 0.0001), respectively. Leptin levels were best predicted by an exponential regression model with GA (Leptin = exp(- 4.41 + 0.14 x GA); r = 0.61; p < 0.0001). Using multivariate regression analysis (r = 0.57; p < 0.0001), we found significant influences of GA (p < 0.00001) and BW SDS (p < 0.05) on leptin levels. No difference was observed between leptin values in AGA versus SGA preterm infants.

CONCLUSION

These data suggest fetal leptin levels to be primarily determined by GA and additionally modulated by growth restriction in term newborns. We found a dramatic increase at weeks 33 to 35 of gestation and no modulation by BW SDS in very preterm infants.

Molecular biological characterization of equine surfactant protein A

In the following, we describe the isolation and sequencing of the equine surfactant protein A (Sp-A) as found in both the cDNA and the genomic DNA. We found a length of the cDNA sequence of 747 bp (base pairs), in translation into amino acids of 248. Compared with the known molecular biological facts about Sp-A in other species, the cDNA sequence obtained showed highest homology with that of sheep (85.01%). The genomic DNA of equine Sp-A, as in other species, includes three introns. There were no hints for the existence of two different Sp-A genes. These results should form the basis for a better understanding of respiratory failure in foals and adult horses, and also lead to further studies on this item.

[Inhibition of meconium induced activation of granulocytes from neonates and adults by pentoxyphylline]

BACKGROUND

Neutrophil activation plays a crucial role in the pathogenesis of the meconium aspiration syndrome. Therefore antiinflammatory strategies may offer therapeutic options. The methylxanthinderivative pentoxyphylline (PTX) is known to inhibit the tumor necrosis factor alpha-synthesis and neutrophil degranulation and thus may have beneficial effects on meconium-induced pulmonary inflammation. Effects of PTX on PMN-degranulation in neonatal whole blood have not yet been studied.

PATIENTS AND METHODS

Heparin-anticoagulated (3 IE/ml) whole blood of healthy neonates (n = 6) and adult volunteers (n = 6) was incubated for 45 min. Spontaneous PMN-degranulation was compared with meconium-induced (3 mg/ml) and PTX-inhibited (0,025 - 0,4 mg/ml) degranulation by means of elastase (EL) and lactoferrin (LF) release from azurophilic and specific granules. EL- and LF plasma concentration was measured by immunoluminometric methods.

RESULTS

Spontaneous degranulation of neonatal PMN was found to be significantly increased after 15 minutes compared with cells from adults (EL and LF concentration: 674 and 660 ng/10 6 PMN vs. 284 and 261 ng/10 6 PMN). At 45 minutes adult PMN showed an acceleration of degranulation in contrast to neonatal cells (EL and LF: 1827 and 1232 ng/10 6 PMN vs. 1400 and 860 ng/10 6 PMN). In presence of PTX (0,4 mg/ml) spontaneous release of EL and LF from neonatal PMN was inhibited by nearly 70 % at 45 min. while degranulation from adult PMN was found to be completely inhibited at 15 min. and reduced by 82 % and 78 % at 45 min. In presence of meconium (3 mg/ml) an increased degranulation of EL from PMN of both neonates and adults (317 % and 170 %) could be observed while LF release was found to be increased from neonatal cells only (267 % and 113 % respectively). PTX inhibited meconium-induced EL release in blood of bath neonates and adults by 63 % and 66 %, while LF release was inhibited by 72 % and 57 % respectively.

CONCLUSION

Neonatal PMN exhibit an increased degranulation from azurophilic and specific granules compared with cells from adults. PTX was found to be an effective inhibitor of spontaneous and meconium induced PMN degranulation and may offer new therapeutic options.

[Colonisation of the airways with ureaplasma urealyticum as a risk factor for bronchopulmonary dysplasia in VLBW infants?]

BACKGROUND

Chronic inflammatory processes contribute to the pathogenesis of bronchopulmonary dysplasia (BPD). We hypothesized colonisation with Ureaplasma urealyticum (Uu) as a possible reason for an increased risk of developing prolonged oxygen dependency > 28 days in very low birth weight (VLBW) infants.

PATIENTS AND METHODS

From January 1998 to November 1999 pharyngeal swabs were prospectively obtained and tested for Uu at birth and then weekly in VLBW infants. The following variables were compared between Uu-positive and Uu-negative infants: prenatal corticosteroids, maternal infections, mode of delivery, gestational age, birth weight, gender distribution, RDS, surfactant therapy, maximum inspiratory oxygen concentration during the first 24 and 48 hours, duration of oxygen supplementation beyond day 28, PDA, and weight differences during the first week of life.

RESULTS

Of a total of 74 infants, 17 were found to be Uu-positive. The latter group showed a lower mean gestational age (29; 25 - 37 vs. 28; 24 - 34 WOG; p = 0.02) and a longer duration of oxygen supplementation after day 28 (0; 0 - 121 vs. 5; 0 - 134 d; p = 0.02). All other variables did not differ significantly between both groups. Multivariate analyses identified the variables birth weight and colonisation with Uu as risk factors for a longer period of oxygen dependency after day 28 (p < 0.01; p = 0.05).

CONCLUSION

These data indicate a correlation between the colonisation with Uu and prolonged oxygen dependency > 28 days.