Rate Of Respiratory Distress Syndrome Research Articles

High levels of positive end-expiratory pressure preserve diaphragmatic contractility during acute respiratory distress syndrome in rats.

What is the central question of this study? Higher levels of positive end-expiratory pressure (PEEP) have recently been used in patients with acute respiratory distress syndrome (ARDS). In normal physiological conditions, the ability of the diaphragm to generate pressure is reduced when the lung volume is elevated beyond its functional residual capacity. It is unknown whether higher levels of PEEP will have a negative impact on diaphragmatic contraction in the presence of the pathophysiology of ARDS. What is the main finding and its importance? Mechanical ventilation with higher levels of PEEP reduced lung injury, improved diaphragmatic contractility and increased the expression of both dihydropyridine receptor and ryanodine receptor in the diaphragms of rats with ARDS. Higher levels of positive end-expiratory pressure (PEEP) have recently been used in patients with acute respiratory distress syndrome (ARDS). In normal physiological conditions, the ability of the diaphragm to generate pressure is reduced when the lung volume is elevated beyond its functional residual capacity. Thus, it is critical to understand whether higher levels of PEEP will have a negative impact on diaphragmatic contraction in the presence of the pathophysiology of ARDS. This study was designed to determine whether higher levels of PEEP reduce diaphragmatic contractility in a rat model of ARDS generated using i.p. lipopolysaccharide. Forty rats were randomly assigned to the following five groups: a control group with no special treatment; an ARDS group with no mechanical ventilation; and three ARDS groups with mechanical ventilation with PEEP at 0, 5 or 10 cmH2 O, respectively. We found that mechanical ventilation with PEEP reduced lung injury, improved diaphragmatic contractility and increased the expression of both dihydropyridine receptor and ryanodine receptor in the diaphragms of rats with ARDS. These changes were most significant at a PEEP of 10 cmH2 O among all applied levels of PEEP. In conclusion, using a rat ARDS model, this study confirmed that diaphragmatic contractility was preserved by mechanical ventilation with high levels of PEEP.

Neonatal Morbidities Associated with Histologic Chorioamnionitis Defined Based on the Site and Extent of Inflammation in Very Low Birth Weight Infants.

Conflicting results on the influences of histologic chorioamnionitis (HC) on neonatal morbidities might be partly originated from using different definition of HC. The aim of this study was to determine the relationship between HC and neonatal morbidities using definition of HC that reflects the site and extent of inflammation. This was a retrospective cohort study of 261 very low birth weight (VLBW) infants admitted at a tertiary academic center. Based on the site of inflammation, HC was categorized: any HC; amnionitis; funisitis; amnionitis+funisitis. The extent of inflammation in each site was reflected by sub-defining high grade (HG). The incidences of morbidities in infants with and without HC were compared. The bronchopulmonary dysplasia (BPD) rate was significantly higher in infants with amnionitis and the severe retinopathy of prematurity (ROP) rate was significantly higher in infants with any HC and funisitis. After adjustment for both gestational age and birth weight, the respiratory distress syndrome (RDS) rate was significantly lower in infants with all categories of HC except for HG amnionitis and HG funisitis, which are not associated with lower RDS rate. HG amnionitis was significantly associated with increased BPD rate but the association of HC with severe ROP disappeared. In conclusion, HC is significantly associated with decreased RDS and HG amnionitis with increased BPD while lacking association with other neonatal morbidities in VLBW infants. The association with HC and neonatal morbidities differs by the site and extent of chorioamnionitis.

Abstract 11446: Systemic Administration of Mitochondria Alleviates 100% Oxygen-Induced Acute Respiratory Distress Syndrome in Rats

Background: We tested the hypothesis that mitochondria-replacement therapy ameliorated 100% oxygen-induced rat acute respiratory distress syndrome (ARDS). Methods and Results: Adult-Male SD rats (n=24) were equally categorized into group 1 (controls, room air inhalation), group 2 (ARDS: induced by inhalation of 100% oxygen for 48 hrs), and group 3 [ARDS + mitochondrial transfusion (1400 μg/each rat) from intra-venous administration 6 h after ARDS induction]. By 72 h after ARDS induction, the oxygen saturation (O 2 -Sat) was significantly lower in group 3 and more significantly lower in group 2 than in group 1, whereas pulmonary artery systolic-blood pressure showed a reversed pattern of O 2 -Sat among three groups (all p<0.001). H&E stain for lung crowded score showed an identical pattern of O 2 -Sat and number of alveolar sacs and lung weight exhibited an opposite pattern of O 2 -Sat among the three groups. The protein expressions of apoptotic (mitochondrial Bax, cleaved caspase 3 & PARP), fibrotic (Smad5, TGF-β), ROS (NOX-1, NOX-2, NOX-4), oxidative stress (oxidized protein), DNA- & mitochondrial-damaged (γ-H2AX, Ki-67; cytosolic cytochrome-c) and inflammatory (TNF-α, MMP-9, NF-κB) biomarkers, and IHC/IF microscopic findings of inflammatory (CD14+, CD68+), DNA-damaged (γ-H2AX+, Ki-67+) cells exhibited an opposite pattern, whereas the protein expressions of anti-apoptotic (Smad1/3, BMP-2) markers exhibited an identical pattern of O 2 -Sat among three groups (all p<0.001). The anti-oxidant (HO-2, NQO-1), mitochondrial-preserved (mitochondrial cytochrome-c) biomarkers, and cellular levels of anti-oxidants (HO-1, NQO-1, GR, GPx) were significantly higher in group 2 and more significantly higher in group 3 than in group 1 (all p<0.0001). Conclusions: Mitochondria therapy protects against 100% oxygen-induced ARDS. Key words: mitochondrial replacement, acute lung injury, inflammation, oxidative stress, DNA and mitochondrial damage

Acute respiratory morbidity in late preterm infants

Background Late preterm (LP) infants [gestational age (GA): 3436 weeks] are at increased risk of neonatal acute respiratory morbidity compared with term infants (GA: 3741) [1,2]. The observed rate of acute respiratory morbidity, in a population of about 20,000 LP infants, was 10-12% vs 1.4% of term infants [1]. Transient tachypnea of the newborn (TTN) and respiratory distress syndrome (RDS) are the most common diagnosis, with RDS rate reaching 10.5% in infants born at 34 weeks of GA [1,2]. Major causes of respiratory morbidity in LP are: prematurity and birth by Cesarean Section (CS) [1,3]. Material and methods We retrospectively studied 830 LP and moderate preterm (MP) infants (GA: 33-36 weeks) admitted to our unit from June 2009 to December 2013. Infants were classified according to GA: 33 weeks (n = 129), 34 weeks (n = 176), 35 weeks (n = 225), 36 weeks (n = 300). Clinical charts for each patient were reviewed and main diagnosis recorded.

Is higher 25-hydroxyvitamin D level preventive for respiratory distress syndrome in preterm infants?

The objective of this study was to investigate the relationship between cord blood 25-hydroxyvitamin D (25(OH)D) levels and respiratory distress syndrome (RDS) development in preterm infants. Between January 2012 and January 2013, 81 preterm infants, gestational age below 32 weeks, were prospectively enrolled into the study. Cord bloods of these newborns were tested for 25(OH)D levels. Low level was defined as ≤ 15 ng/mL (Group 1) and normal level as > 15 ng/mL (Group 2). Patients in Group 1 were also divided further into two subgroups as severe deficiency (Group 1a, ≤ 5 ng/mL) and mild deficiency (Group 1b, 5-15 ng/mL). In this study, 57 infants had low 25(OH)D levels (Group 1, median 8.0 ng/mL [interquartile range, IQR, 5-10]; Group 2, median 21 ng/mL [IQR, 19-24.7]). RDS rate was significantly higher in Group 1a (n = 18, 32.7%) and Group 1b (n = 34, 61.8%) compared with Group 2 (n = 3, 5.4%) (p = 0.001). There were no difference of having RDS between Group 1a (94.7%) and Group1b (89.5) (p = 0.512). Multivariate analysis showed that higher 25(OH)D level can be preventive for the development of RDS (odds ratio, 0.6; 95% confidence interval (0.5-0.8); p = 0.001). Lower cord blood 25(OH)D levels might be associated with increased risk of RDS in preterm infants with very low birth weight.

Optimal time interval between a single course of antenatal corticosteroids and delivery for reduction of respiratory distress syndrome in preterm twins

The objective of the study was to investigate the effect of a single course of antenatal corticosteroid (ACS) therapy on the incidence of respiratory distress syndrome (RDS) in preterm twins according to the time interval between ACS administration and delivery. We performed a retrospective cohort study of twins born between 24 and 34 weeks of gestation from November 1995 to May 2011. Subjects were grouped on the basis of the time interval between the first ACS dose and delivery: the ACS-to-delivery interval of less than 2 days (n = 166), 2-7 days (n = 114), and more than 7 days (n = 66). Pregnancy and neonatal outcomes of each group were compared with a control group of twins who were not exposed to ACS (n = 122). Multiple logistic regression analysis was used to examine the association between the ACS-to-delivery interval and the incidence of RDS after adjusting for potential confounding variables. Compared with the ACS nonexposure group, the incidence of RDS in the group with an ACS-to-delivery interval of less than 2 days was not significantly different (adjusted odds ratio [aOR], 1.089; 95% confidence interval [CI], 0.524-2.262; P = .819). RDS occurred significantly less frequently when the ACS-to-delivery interval was between 2 and 7 days (aOR, 0.419; 95% CI, 0.181-0.968; P = .042). However, there was no significant reduction in the incidence of RDS when the ACS-to-delivery interval exceeded 7 days (aOR, 2.205; 95% CI, 0.773-6.292; P = .139). In twin pregnancies, a single course of ACS treatment was associated with a decreased rate of RDS only when the ACS-to-delivery interval was between 2 and 7 days.

Randomized, placebo controlled, double blind trial evaluating early pregnancy phytonutrient supplementation in the prevention of preeclampsia

Daily provision of pregnant patients with dietary supplements containing antioxidants and phytonutrients, if initiated in the first trimester of pregnancy and continued throughout the gestation, may significantly decrease the incidence of preeclampsia. We conducted a single center, randomized, placebo-controlled investigation in which women were randomized by their risk status and assigned to daily ingestion of a supplement consisting primarily of a blended fruit and vegetable juice powder concentrate or placebo. Of the 684 patients randomized to the trial, 267 (39.0%) completed it. The final analysis is based on those participants who completed the study. For the primary outcome of preeclampsia, there was no difference observed between the phytonutrient supplement group and the placebo group: 15.9% vs 16.3%, respectively, (R.R. 0.97 (0.56-1.69)). Non-significant trends toward lower placenta-related obstetrical complications were observed in the supplement group compared with the placebo cohort (8.3% vs 15.5%, respectively, (R.R. 0.57 (0.29-1.14). Those infants born to mothers taking the supplement in the high-risk stratified group demonstrated non-significant trends toward lower rates of respiratory distress syndrome (RDS); 5.3% in the supplement group vs 15.4% in the placebo group: R.R. 0.34 (0.12-1.01). Initiation of antioxidant/phytonutrient supplementation in the first trimester did not decrease rates of preeclampsia. Non-significant trends toward lower incidences of placental derived morbidity in those mothers taking the supplement in addition to decreased rates of RDS in infants born to supplemented mothers considered to be high-risk for preeclampsia, warrant further investigation.

Persistent ovarian masses and pregnancy outcomes

Objective: To determine if persistent ovarian masses in pregnancy are associated with increased adverse outcomes.Methods: This is a retrospective cohort of 126 pregnant women with a persistent ovarian mass measuring 5 cm or greater who delivered at two university hospitals between 2001 and 2009. Maternal outcomes included gestational age (GA) at diagnosis, delivery and surgery as well as miscarriage, preterm birth (PTB), ovarian torsion and hospital admission for pain. Neonatal outcomes included birth weight, respiratory distress syndrome (RDS), intra-ventricular hemorrhage (IVH), death and sepsis.Results: A total of 1225 ovarian masses were identified (4.9%) in 24 868 patients. A persistent ovarian mass was found in 0.7%. Average GA at diagnosis was 17.8 weeks. Miscarriage rate was 3.3%. Average GA at delivery was 37.9 weeks. Of the patients, 8.5% had ovarian torsion, 10.3% had admission for pain and 9.3% had PTBs. The mean cesarean delivery rate was 46.3%. The average neonatal weight was 3273 g. There was one neonatal death in this cohort. The rate of RDS was 2.8%, IVH 0.9% and neonatal sepsis 1.9%. The most common surgical pathologic diagnosis was dermoids (37.6%). No overt malignancies were seen.Conclusion: A persistent ovarian mass in pregnancy does not confer an increased risk of adverse pregnancy outcomes.

90: Oral misoprostol vs vaginal dinoprostone for labor induction in nulliparous women at term

between 34 0 and 36 6 weeks of gestation Giuliana Simonazzi, Alessandra Curti, Elisa Moro, Andrea Pedrazzi, Tiziana Martina, Antonio Farina, Nicola Rizzo St. Orsola Malpighi Hospital, University of Bologna, Department of Obstetrics & Gynecology, Bologna, Italy OBJECTIVE: To assess the impact of mode of delivery on respiratory morbidity among late-preterm neonates. STUDY DESIGN: Singleton pregnancies complicated by premature rupture of membranes (PROM) between 34 0 and 36 6 weeks were studied retrospectively. Pregnancies with corticosteroid administration after 34 6 weeks were excluded. Patients were divided into cesarean section (CS) and vaginal delivery groups, matched 1:3 for gestational age. The primary outcome was the rate of respiratory distress syndrome (RDS). Logistic regression was performed to assess the risk of RDS within groups. RESULTS: Between 2005 and 2012, 360 patients delivered between 34 and 36 weeks after premature rupture of membranes at St. OrsolaMalpighi Hospital, Bologna (Italy). In 90 cases elective caesarean section was performed for previous CS (n 50), breech presentation (n 31) or maternal medical indications (n 9). No difference was found for antenatal betamethasone within groups. The overall RDS rate was 15%, while it was 30% and 10% in case of CS and vaginal delivery, respectively (p-value 0.0001). CS seems to be a risk factor for RDS (OR 4.2, p-value 0,0001), as does earlier gestational age at delivery (OR 0.9, p-value 0,0001). Table 1 shows the median risks of RDS in the study population according to the logistic regression model. CONCLUSION: After preterm PROM, CS is associated with a higher risk of neonatal RDS. This is more evident with increasing gestational age, when respiratory morbidity is thought to be less frequent.

Role of Fetal Sex in the Outcome of Antenatal Glucocorticoid Treatment to Prevent Respiratory Distress Syndrome: Systematic Review and Meta-Analysis

BackgroundAntenatal glucocorticoid (AGC) therapy has been associated with a decrease in respiratory distress syndrome (RDS). While preterm males remain at greater risk of RDS than females, the role of fetal sex in AGC response is not well known. ObjectivesTo review the available evidence regarding the effect of fetal sex in the prevention of RDS using AGC. MethodWe conducted a systematic review and meta-analysis of RCTs to compare the effect of AGC in male and female infants with regard to the rates of RDS, intra-ventricular hemorrhage (IVH) grades III and IV, and neonatal mortality. Random effects with 95% confidence intervals were assessed in both groups and relative risks were compared using mixed regression. ResultsFrom 248 potentially eligible articles, we included eight in the analysis for a total of 1109 male and 968 female infants. Both male and female infants had a significant decrease in the risks, but no difference between the sexes was observed in terms of reduction in RDS (RR 0.50; 95% CI 0.33 to 0.77 for males, and RR 0.57; 95% CI 0.43 to 0.75 for females, P = 0.99), reduction in IVH (P = 0.98), and reduction in neonatal mortality (P = 0.43). In a sub-analysis, use of betamethasone was associated with a significant decrease in the rate of RDS in males (RR 0.29; 95% CI 0.15 to 0.57) but dexamethasone was not (RR 0.78; 95% CI 0.57 to 1.07). Conversely, dexamethasone use was significantly helpful in females (RR 0.51; 95% CI 0.32 to 0.81) but betamethasone was not (RR 0.62; 95% CI 0.38 to 1.00). ConclusionThe effect of AGC for prevention of RDS is similar in females and males. However, futures studies should investigate the type of AGC according to fetal/neonatal sex.

The presence of funisitis is associated with a decreased risk for the development of neonatal respiratory distress syndrome

Objectives Fetal lung maturation and respiratory outcomes are influenced by the exposure to intrauterine inflammation. Funisitis is considered as the histologic hallmark of fetal inflammatory response. This study was performed to determine if there is a difference in the rate of neonatal respiratory distress syndrome (RDS) according to the presence or absence of funisitis in preterm gestations. Study design The relationship between the presence of funisitis and the development of neonatal RDS was examined in 301 consecutive singleton preterm births (24–32 weeks’ gestation). Cases without placental histological examination and those with major congenital anomalies were excluded. Funisitis was diagnosed in the presence of neutrophil infiltration into the umbilical vessel walls or Wharton’s jelly on the placental histological examination. Results Funisitis was diagnosed in 25% and RDS was diagnosed in 46% of cases. The rate of RDS in babies with funisitis was lower than in those without funisitis (28.4% vs. 51.1%, p = 0.001). Logistic regression analysis demonstrated that the presence of funisitis was associated with a decreased risk for RDS after adjusting for confounding variables (Odds ratio = 0.44, 95% CI 0.22–0.90). The downward trend of the frequency of RDS was related to the presence of histologic chorioamnionitis and funisitis ( p < 0.001). Conclusions The presence of funisitis is associated with a decreased risk for the development of neonatal RDS in preterm gestations. Furthermore, this observation suggests that the fetal involvement of placental inflammation may be beneficial to the maturation of the fetal lung.

186: The presence of funisitis is associated with a decreased risk for the development of neonatal respiratory distress syndrome

Objectives: Fetal lung maturation and respiratory outcomes are influenced by the exposure to intrauterine inflammation. Funisitis is considered as the histologic hallmark of fetal inflammatory response. This study was performed to determine if there is a difference in the rate of neonatal respiratory distress syndrome (RDS) according to the presence or absence of funisitis in preterm gestations. Study design: The relationship between the presence of funisitis and the development of neonatal RDS was examined in 301 consecutive singleton preterm births (24e32 weeks’ gestation). Cases without placental histological examination and those with major congenital anomalies were excluded. Funisitis was diagnosed in the presence of neutrophil infiltration into the umbilical vessel walls or Wharton’s jelly on the placental histological examination. Results: Funisitis was diagnosed in 25% and RDS was diagnosed in 46% of cases. The rate of RDS in babies with funisitis was lower than in those without funisitis (28.4% vs. 51.1%, p ¼ 0.001). Logistic regression analysis demonstrated that the presence of funisitis was associated with a decreased risk for RDS after adjusting for confounding variables (Odds ratio ¼ 0.44, 95% CI 0.22e0.90). The downward trend of the frequency of RDS was related to the presence of histologic chorioamnionitis and funisitis (p < 0.001). Conclusions: The presence of funisitis is associated with a decreased risk for the development of neonatal RDS in preterm gestations. Furthermore, this observation suggests that the fetal involvement of placental inflammation may be beneficial to the maturation of the fetal lung.

Active Versus Expectant Management for Preterm Prelabor Rupture of Membranes at 34–36 Weeks of Completed Gestation: Comparison of Maternal and Neonatal Outcomes

There is general agreement among obstetricians that women with preterm prelabor rupture of membranes (PPROM) should be expectantly managed at least until 34 completed weeks of gestation. However, there is little agreement concerning the choice between active management (AM) and expectant management (EM) from 34 to 36 weeks of gestation, and the choice during this period remains highly controversial. Four randomized trials compared EM with AM in cases of PPROM before 37 weeks. These studies reported no overall difference between these 2 types of management for length of stay in the neonatal intensive unit, respiratory distress syndrome (RDS), or confirmed neonatal sepsis, but clinical chorioamnionitis was found less frequently in AM than in EM. Because of design problems, the external validity of these 4 studies is unclear. This retrospective multicenter study compared the effect of management with AM or EM on maternal and neonatal outcomes among a population of women who had PPROM at 34 to 36 completed weeks of gestation. Outcomes examined included maternal chorioamnionitis and neonatal morbidity including neonatal infection, respiratory problems, and metabolic disorders. Respiratory problems examined included RDS and the need for oxygen supplementation for more than 2 hours. Data were obtained from medical charts for deliveries occurring between 1999 and 2005 at 3 university hospital centers. Of the 51,997 women who gave birth during the study period, 634 were admitted for PPROM at 34 to 36 completed weeks of gestation. A total of 393 women did not meet eligibility criteria and were excluded from analysis, leaving 241 women—126 in the EM group and 115 in the AM group. The incidence of clinical chorioamnionitis was significantly higher in the EM group compared with the AM group (4.8% vs. 0.9%; (P = 0.07). Although there was no significant difference between the 2 groups in RDS rates, more babies in the AM compared with the EM group required oxygen at 24 hours (7.0 vs. 1.6%, P = 0.05). Only delivery at 34 weeks of gestation remained associated with the need for neonatal oxygen at 24 hours following adjustment for gestational age at delivery. The rate of hypoglycemia or hypocalcemia was higher in the AM group (AM: 12.3% vs. EM: 5.6%, P = 0.07). No neonatal deaths occurred. These findings indicate that management of PPROM using a policy of AM, especially at 34 weeks of gestation, is associated with greater neonatal morbidity, and an EM policy with a higher rate of clinical chorioamnionitis. The choice between AM or EM at 34 to 36 weeks of gestation remains controversial.

Antenatal Corticosteroids and Outcome in a Very Low Birth Weight in Qatar

Respiratory Distress Syndrome (RDS) causes significant mortality and morbidity in babies born before 32 weeks gestation. To determine the effectiveness of antenatal steroid treatment (ANS) in reducing neonatal morbidity from respiratory distress syndrome, and patent ductus arteriosus (PDA), intra-ventricular haemorrhage (IVH), and retinopathy of prematurity (ROP) in very low birth weight infants, a retrospective case control study examined the medical records of 125 babies born before 32 weeks gestation. Divided into two groups according to whether or not antenatal corticosteroids were given, the groups did not differ in rates of RDS, IVH, PDA, or ROP but the group that did not receive ANS had a significantly higher risk of death (p &lt; 0.05).

Intratracheal Instillation of Surfactant Inhibits Lipopolysaccharide-induced Acute Respiratory Distress Syndrome in Rats

To determine the possible contribution of apoptosis in the pathogenesis of ARDS, we investigated the role of exogenous surfactant in a rodent model of ARDS after intratracheal instillation of lipopolysaccharide. Adult male Sprague Dawley rats were divided into four groups: buffer controls; rats challenged with LPS (055:B5 E.coli); challenged with LPS and treated with porcine surfactant (P-SF); and challenged with LPS and treated with synthetic surfactant (S-SF). Parameters of lung injury and inflammation were assessed 72h after treatment. We demonstrated that intratracheal administration of LPS could provoke significant lung injury, which was characterized by increase of MPO activity, wet/dry lung weight ratio, cytokine levels in bronchoalveolar lavage fluid (BALF), apoptosis of BALF cells and caspase-3 activity in lung tissue. Intratracheally delivered surfactant significantly reduced the parameters of LPS-induced inflammation: infiltration of inflammatory cells into lung tissue and BALF, pulmonary edema, lung myeloperoxidase activity, lipid peroxidation, caspase-3 activity, number of apoptotic BALF cells, lactate dehydrogenase level & pro-inflammatory cytokines levels. Taken together, the present data demonstrate that exogenous surfactant systemically attenuates lipopolysaccharide-induced inflammation.

Core Concepts

Respiratory distress syndrome (RDS) is seen primarily in the preterm neonate and is due mostly to pulmonary surfactant deficiency. Lung atelectasis leads to ventilation-perfusion mismatching, hypoxia, and eventual respiratory failure in the untreated infant who has RDS. RDS is diagnosed by physical findings consistent with respiratory distress and characteristic radiographic findings. Treatment of RDS begins antenatally with the administration of maternal steroids to women at risk of preterm delivery between 24 and 34 weeks’ gestation. The use of repeat doses of antenatal steroids is under investigation but is currently not recommended outside of randomized, controlled trials. SRT has been approved for use since 1990 and has been successful in decreasing rates of RDS. Natural surfactant is currently recommended for use, but synthetic surfactant that contains proteins to mimic surfactant proteins is being investigated. In general, prophylactic use of surfactant is recommended over rescue treatment in infants at high risk for developing RDS, but the determination of which infants are at high risk for developing RDS remains a clinical one. The push toward use of less invasive ventilation strategies in the treatment of RDS has led to several trials of nasal continuous positive airway pressure (nCPAP). Results of the SUPPORT trial are pending, but the COIN trial has concluded that nCPAP use in infants who have RDS is not detrimental. Inhaled nitric oxide for RDS still requires investigation on safety and efficacy. Several other treatments have been studied, but as of yet, only inositol administration shows promise in the treatment of RDS. Several complications of the recommended treatments for RDS have been identified, but the benefits far outweigh the risks. Finally, there remains a need for long-term follow-up studies on preterm infants treated for RDS to assess neurodevelopmental outcomes.

Impact of mode of delivery on neonatal complications: Trends between 1997 and 2005

Objective. This study examined whether rates of selected neonatal complications vary by mode of delivery and whether these rates are changing as a result of the increasing cesarean delivery rate.Method. Birth certificates in New Jersey from 1997 to 2005 were matched to hospital discharge records for mothers and newborns.Results. In New Jersey, the total cesarean section rate for 2005 was 35.3%, a relative increase of 46% since 1997 (from 24.2%). Rates of transient tachypnea of the newborn (TTN) and respiratory distress syndrome (RDS), regardless of mode of delivery, increased between 1997 and 2005 from 3.3 to 3.9% and 2.1 to 2.4%, respectively. Newborn injuries declined sharply (from 4.1 to 2.6%), whereas intra-ventricular hemorrhage (IVH) rates remained stable. The rates of RDS, TTN and IVH were highest for cesarean delivery without trial of labor, while the rate of injuries was highest for instrumental vaginal delivery.Conclusion. Neonatal complication rates varied by mode of delivery and decreased with gestational age.

Timing of Planned Cesarean Delivery by Racial Group

To estimate the incidence of newborn respiratory distress syndrome (RDS) and transient tachypnea of the newborn (TTN) in relation to gestational age and planned cesarean delivery in white, South Asian, and black women. Included in this study were 442,596 white, South Asian, and black women who delivered single live infants at 28 of weeks gestation onwards between 1988 and 2000. Using multiple logistic regression, the gestation-specific patterns of RDS for all deliveries and RDS plus TTN for deliveries by planned cesarean delivery were analyzed by racial group. The predictors of RDS from 37 weeks of gestation onwards were determined. More South Asians (28.2%, 95% confidence interval [CI] 27.8-28.6) and blacks (24.6%, 95% CI 24.0-25.1) delivered spontaneously before 39 weeks than whites (16.9%, 95% CI 16.8-17.1). Respiratory distress syndrome patterns by gestation differed significantly (P<.001). Compared with whites, the gestation-specific crude RDS rate was lower in South Asians up until 40 weeks and after adjusting for confounders; South Asians were most protected against RDS (odds ratio [OR] 0.6, 95% CI 0.5-0.9). The gestation-specific patterns of RDS plus TTN after planned cesarean delivery also differed significantly (P<.001) between racial groups. The lowest rate of TTN plus RDS was at 40 weeks for whites, but in South Asians and blacks, it was lowest at 38 weeks. The gestation-specific patterns of RDS differed significantly by racial group from 32 weeks of gestation onwards. Preterm black infants had a lower rate of RDS when compared with whites; also, South Asians had the lowest rate of transient tachypnea until 38 weeks and the lowest rate of RDS until 40 weeks of gestation. The advantages of waiting until 39 weeks to perform planned cesarean delivery for white women are not seen in South Asians or blacks.

Is meconium-stained amniotic fluid in near-term infants associated with increased rates of adverse maternal and neonatal outcomes?

WITH INCREASED RATES OF ADVERSE MATERNAL AND NEONATAL OUTCOMES? SUSAN TRAN, ANJALI KAIMAL, MICHAEL KUZNIEWICZ, AARON CAUGHEY, University of California, San Francisco, Obstetrics, Gynecology and Reproductive Sciences, San Francisco, California, University of California, San Francisco, Pediatrics, San Francisco, California OBJECTIVE: To evaluate neonatal and maternal outcomes in near-term pregnancies complicated by meconium-stained amniotic fluid (MSAF). STUDY DESIGN: This is a retrospective cohort study of 3,480 deliveries between 32-0/7 and 36-6/7 weeks gestation. Neonatal outcomes included: Apgar scores, intensive care nursery (ICN) admission, sepsis, meconium aspiration syndrome (MAS), and respiratory distress syndrome (RDS). Maternal outcomes included: endomyometritis, postpartum hemorrhage, blood transfusion, operative vaginal delivery, and cesarean delivery. Bivariate and multivariate analyses were performed. RESULTS: MSAF was associated with an increased risk of adverse neonatal outcomes except RDS when compared to pregnancies with clear amniotic fluid in the bivariate analyses (Table). No differences were found in maternal outcomes, except for an increased risk of maternal transfusion in the MSAF group. Adjusting for ethnicity, maternal age, gestational age, birthweight, antenatal corticosteroid administration, year of delivery, and cesarean section, MSAF remained associated with increased risks of 5 minute Apgar score !7, sepsis, and maternal blood transfusion, and a decreased risk for RDS (Table). CONCLUSION: We found that MSAF occurring at 32 – 36-6/7 weeks’ gestation was only associated with 5 minute Apgar score !7 when controlling for potential confounding variables. MSAF in these near-term infants was inversely associated with RDS. This is consistent with the findings that with increasing gestational ages, rates of MSAF tend to increase, while rates of RDS tend to decrease. These findings differ somewhat in comparison to term infants with MSAF, suggesting that meconium passage at these earlier gestational ages may represent a different pathophysiologic process.

Preventive effects and mechanism of heme oxygenase-1 activation on acute respiratory distress syndrome in rats

To explore the possible mechanism of heme oxygenase-1 (HO-1) induction for its protective effects on acute respiratory distress syndrome (ARDS). The production of HO-1 was induced by hemoglobin (Hb) injection into oleic acid (OA) induced ARDS rats. Western blot and RT-PCR techniques were used to observe the induction of HO-1 in vivo. Both the levels of tumor necrosis factor-alpha (TNF-alpha) and interleukin-8 (IL-8) in serum and bronchoalveolar lavage fluid (BALF) were measured by enzyme linked immunosorbent assay (ELISA). Combined with blood gas analysis and other indexes, the effect of HO-1 on ARDS could be clearly manifested. The expression of HO-1 mRNA was increased significantly 16 h after Hb injection, and the protein expression of HO-1 was also obviously increased 24 h later (P < 0.01). The levels of TNF-alpha and IL-8 in both serum and BALF were significantly lower in Hb + OA group than in OA group (P < 0.01). Arterial blood PaO(2), oxygen saturation, and oxygenated index in Hb + OA group [(56.28 +/- 6.71) mm Hg, (79.53 +/- 5.82)%, and (258.81 +/- 29.37) mm Hg respectively] were higher than in OA group [(35.08 +/- 4.59) mm Hg, (55.80 +/- 12.76)%, and (167.86 +/- 21.94) mm Hg]. Lung wet and dry weight, and pathological changes were also improved. The production of HO-1 was successfully induced by hemoglobin in vivo. Protective effects of HO-1 on ARDS might be related to the decreasing in inflammatory factors, such as TNF-alpha and IL-8.