Meconium-stained amniotic fluid and meconium aspiration syndrome: a prospective study

Meconium-stained amniotic fluid and neonatal morbidity in nulliparous patients with prolonged pregnancy

INTRODUCTION

Our objective was to study the strength of the association between meconium-stained amniotic fluid and severe morbidity among neonates of nulliparas with prolonged pregnancies.

MATERIAL AND METHODS

This was a secondary analysis of the NOCETER randomized trial that took place between 2009 and 2012 in which 11 French maternity units included 1373 nulliparas at 41⁺⁰  weeks of gestation onwards with a single live fetus in cephalic presentation. This analysis excluded patients with a cesarean delivery before labor and those with bloody amniotic fluid or of unreported consistency. The principal end point was a composite criterion of severe neonatal morbidity (neonatal death, 5-minute Apgar <7, convulsions in the first 24 h, meconium aspiration syndrome, mechanical ventilation ≥24 h, or neonatal intensive care unit admission for 5 days or more). The neonatal outcomes of pregnancies with thin or thick meconium-stained amniotic fluid were compared with those with normal amniotic fluid. The association between the consistency of the amniotic fluid and neonatal morbidity was tested by univariate and then multivariate analysis adjusted for gestational age at birth, duration of labor, and country of birth.

RESULTS

This study included 1274 patients: 803 (63%) in the group with normal amniotic fluid, 196 (15.4%) in the thin amniotic fluid group, and 275 (21.6%) in the thick amniotic fluid group. The neonates of patients with thick amniotic fluid had higher rates of neonatal morbidity than those of patients with normal amniotic fluid (7.3% vs. 2.2%; p < 0.001; adjusted relative risk [aRR] 3.3, 95% confidence interval [CI] 1.7-6.3), but those of patients with thin amniotic fluid did not (3.1% vs. 2.2%; p = 0.50; aRR 1.0, 95% CI, 0.4-2.7).

CONCLUSIONS

Among nulliparas at 41⁺⁰  weeks onwards, only thick meconium-stained amniotic fluid is associated with a higher rate of severe neonatal morbidity.

Clinical characteristics of meconium aspiration syndrome in neonates with different gestational ages and the risk factors for neurological injury and death: A 9-year cohort study

Background

The presence of meconium is associated with gestational age, and the incidence of meconium aspiration syndrome (MAS) increases with gestational age. Our study compared the differences in the clinical characteristics of patients with MAS at different gestational ages and discussed the risk factors for neurological injury and death from MAS.

Methods

A total of 294 neonates diagnosed with MAS between 2013 and 2021 were included. Patients were divided into preterm, early-term, full-term, and late-term groups according to gestational age. We compared the patients' basic demographic, treatment, complications, and clinical outcomes in the different groups. We also analyzed the risk factors of neurological injury and death in patients with MAS.

Results

The mean age at admission (0.55 ± 0.9 h) was lower and the proportion of cesarean deliveries (90.00%, 27/30) was higher in the preterm group than in the other three groups. There was no statistically significant difference among the four groups regarding 1- and 5-min Apgar scores and the need for delivery room resuscitation. In terms of complications, early-term infants had the highest incidence of neurological injury (52.9%, 27/51), and late-term infants had the highest incidence of pneumothorax (37.8%, 17/45). The overall mortality rate of children with MAS was 7.80% (23/294), and the difference in mortality rates among the four groups was not significant. Low 1-min Apgar score and gestational age, metabolic acidosis, and respiratory failure were independent risk factors for neurological injury; metabolic acidosis, respiratory failure, and sepsis were independent risk factors for death in neonates with MAS.

Conclusion

The clinical characteristics of MAS neonates of different gestational age are different mainly in complications. Early-term infants are more likely to complicate with neurological injury, and late-term infants are more likely to complicate with pneumothorax. Low 1-min Apgar score and gestational age, metabolic acidosis, and respiratory failure were established as risk factors for neurological injury; metabolic acidosis, respiratory failure, and sepsis were independent risk factors for death in neonates with MAS.

The incidence and determinants of the meconium-aspiration syndrome among mothers with meconium-stained amniotic fluid after emergency cesarean section: A prospective cross-sectional study in a specialized hospital, south Ethiopia

Background

Meconium aspiration syndrome is respiratory distress diagnosed in neonates delivered with meconium-stained amniotic fluid that is unexplained by other pathologies. It has severe neonatal respiratory complications and a significant impact on the prevalence of neonatal mortality.

Objective

To identify the incidence and determinants associated with meconium aspiration syndrome among mothers with meconium-stained amniotic fluid after emergency cesarean section in Wolkite University specialized hospitals in Ethiopia from September 1, 2021, to August 30, 2022.

Method

An institution-based cross-sectional study was done prospectively through meticulous chart review and interviews with 275 mothers with meconium-stained amniotic fluid who gave birth with an emergency cesarean section. Data were entered using EpiData 7 and analyzed with SPSS 26. The association between independent variables and the meconium-aspiration syndrome was estimated using an odds ratio with 95% confidence intervals. The statistical significance of the association was declared at a p-value of 0.05.

Result

The prevalence of the meconium-aspiration syndrome is 28.7%. The factors associated are: latent phase (AOR: 2.580; 95% CI: 1.126, 5.913), low 1st minute APGAR score (AOR: 2.43; 95% CI: 0.892, 6.625), and thick meconium (AOR: 31.018; 95% CI: 9.982, 96.390). The neonatal death rate associated with meconium aspiration syndrome is 1.8%, and thick meconium contributed to 65% of admissions to the neonatal intensive care unit and all deaths.

Conclusion

The incidence of meconium aspiration syndrome is high, and thick meconium, meconium at early labor, and low APGAR scores all contributed to this. Thick meconium has a substantial effect on neonatal mortality and morbidity. Therefore, an improvement in the quality of obstetric and neonatal care through early intervention in the case of thick meconium and meconium in the early phase of labor is recommended.

Neonates Born Through Meconium-stained Amniotic Fluid among Deliveries in a Tertiary Care Centre: A Descriptive Cross-sectional Study

Introduction

The mortality and morbidity of meconium aspiration syndrome in neonates born with meconium-stained amniotic fluid in developing countries are still high. In Nepal, few studies have estimated the prevalence of meconium-stained amniotic fluid among newborns. The study aimed to find out the prevalence of neonates born through meconium-stained amniotic fluid among deliveries in a tertiary care centre.

Methods

This descriptive cross-sectional study was conducted among neonates born in a tertiary care centre from November 2021 to March 2022. Neonates born during the study period with meconium-stained amniotic fluid were studied. Ethical approval was obtained from the Institutional Review Committee. Convenience sampling method was used. With permission from the Department of the Neonatal Intensive Care Unit, the data were collected and entered in a Microsoft Excel sheet. Point estimate and 95% Confidence Interval were calculated.

Results

Among 576 neonates, the prevalence of neonates born through meconium-stained amniotic fluid was 77 (13.37%) (10.59-16.15, 95% Confidence Interval).

Conclusions

The prevalence of neonates born through meconium-stained amniotic fluid was found to be similar to other studies done in similar settings.

Keywords

meconium; neonate; Nepal.

Approach to the Connection between Meconium Consistency and Adverse Neonatal Outcomes: A Retrospective Clinical Review and Prospective In Vitro Study

Whether meconium-stained amniotic fluid (MSAF) serves as an indicator of fetal distress is under debate; however, the presence of MSAF concerns both obstetricians and pediatricians because meconium aspiration is a major contributor to neonatal morbidity and mortality, even with appropriate treatment. The present study suggested that thick meconium in infants might be associated with poor outcomes compared with thin meconium based on chart reviews. In addition, cell survival assays following the incubation of various meconium concentrations with monolayers of human epithelial and embryonic lung fibroblast cell lines were consistent with the results obtained from chart reviews. Exposure to meconium resulted in the significant release of nitrite from A549 and HEL299 cells. Medicinal agents, including dexamethasone, L-Nω-nitro-arginine methylester (L-NAME), and NS-398 significantly reduced the meconium-induced release of nitrite. These results support the hypothesis that thick meconium is a risk factor for neonates who require resuscitation, and inflammation appears to serve as the primary mechanism for meconium-associated lung injury. A better understanding of the relationship between nitrite and inflammation could result in the development of promising treatments for meconium aspiration syndrome (MAS).

Time needed to intubate and suction a manikin prior to instituting positive pressure ventilation: a simulation trial

Tracheal suctioning in non-vigorous newborn delivered through meconium-stained amniotic fluid (MSAF) is supposed to delay initiation of positive pressure ventilation (PPV), but the magnitude of such delay is unknown. To compare the time of PPV initiation when performing immediate laryngoscopy with intubation and suctioning vs. performing immediate PPV without intubation in a manikin model. Randomized controlled crossover (AB/BA) trial comparing PPV initiation with or without endotracheal suctioning in a manikin model of non-vigorous neonates born through MSAF. Participants were 20 neonatologists and 20 pediatric residents trained in advanced airway management. Timing of PPV initiation was longer with vs. without endotracheal suctioning in both pediatric residents (mean difference 13 s, 95% confidence interval 8 to 18 s; p < 0.0001) and neonatologists (mean difference 12 s, 95% confidence interval 8 to 16 s; p < 0.0001). The difference in timing of PPV initiation was similar between pediatric residents and neonatologists (mean difference - 1 s, 95% confidence interval - 7 to 6 s; p = 0.85).Conclusions: Performing immediate laryngoscopy with intubation and suctioning was associated with longer-but not clinically relevant-time of initiation of PPV compared with immediate PPV without intubation in a manikin model. While suggesting negligible delay in starting PPV, further studies in a clinical setting are warranted.Registration: clinicaltrial.gov NCT04076189. What is Known: • Management of the non-vigorous newborn delivered through meconium-stained amniotic fluid remains still controversial. • Tracheal suctioning in non-vigorous newborn delivered through meconium-stained amniotic fluid is supposed to delay initiation of positive pressure ventilation, but the magnitude of such delay is unknown. What is New: • Performing immediate ventilation without intubation was associated with shorter-but not clinically relevant-time of initiation of ventilation compared to immediate laryngoscopy with intubation and suctioning in a manikin model. • Further studies in a clinical setting are warranted.

Risk factors for mortality among neonates admitted to a special care unit in a low-resource setting

Background

Although under-5 mortality has decreased in the last two decades, neonatal mortality remains a global health challenge. Despite achieving notable progress, Ethiopia has still one of the highest neonatal mortality rates worldwide. We aimed to assess the risk factors for mortality among neonates admitted to a special care unit in a referral hospital in rural Ethiopia.

Methods

This was a retrospective observational study including all 4182 neonates admitted to the special care unit of the St. Luke Wolisso Hospital (Ethiopia) from January 2014 to December 2017. Data were retrieved from hospital charts and entered in an anonymized dataset. A logistic regression model was applied to identify predictors of mortality and effect sizes were expressed as odds ratios with 95% confidence intervals.

Results

Proportion of deaths was 17% (709/4182 neonates). Neonates referred from other health facilities or home (odds ratio 1.52, 95% confidence interval 1.21 to 1.91), moderate hypothermia at admission (odds ratio 1.53, 95% confidence interval 1.09 to 2.15) and diagnosis of late-onset sepsis (odds ratio 1.63, 95% confidence interval 1.12 to 2.36), low birthweight (odds ratio 2.48, 95% confidence interval 2.00 to 3.09), very low birthweight (odds ratio 11.71, 95% confidence interval 8.63 to 15.94), extremely low birthweight (odds ratio 76.04, 95% confidence interval 28.54 to 263.82), intrapartum-related complications (odds ratio 4.69, 95% confidence interval 3.55 to 6.20), meconium aspiration syndrome (odds ratio 2.34, 95% confidence interval 1.15 to 4.43), respiratory distress (odds ratio 2.25, 95% confidence interval 1.72 to 2.95), other infections (odds ratio 1.92, 95% confidence interval 1.31 to 2.81) or malformations (odds ratio 2.32, 95% confidence interval 1.49 to 3.57) were associated with increased mortality. Being admitted in 2017 vs. 2014 (odds ratio 0.71, 95% confidence interval 0.52 to 0.97), and older age at admission (odds ratio 0.95, 95% confidence interval 0.93 to 0.97) were associated with decreased likelihood of mortality.

Conclusions

The majority of neonatal deaths was associated with preventable and treatable conditions. Education on neonatal resuscitation and postnatal management, and the introduction of an on-call doctor for high-risk deliveries might have contributed to the reduction in neonatal mortality over time.

The effect of meconium thickness level on neonatal outcome

BACKGROUND

Despite its prevalence and potential maternal and neonatal implications, the literature on the thickness levels of meconium stained amniotic fluid (MSAF) and its impact on neonatal outcomes is relatively outdated and relies on relatively small sample sizes.

AIMS

To study if different thickness levels of MSAF correlate with adverse neonatal outcome.

STUDY DESIGN

A retrospective cohort study.

SUBJECTS

The medical records and neonatal charts of all women with a singleton pregnancy, who underwent a trial of labor, at 37 + 0/7 weeks or beyond, between 10/2008 and 7/2018 were reviewed.

OUTCOME MEASURES

The cohort was divided according to the level of meconium reported during labor into four groups: Clear (C group), Light meconium (LM group), Intermediate meconium (IM group), and Heavy meconium (HM group). Composite neonatal outcome included at least one of the following: umbilical artery pH ≤ 7.1, sepsis, need for blood transfusion, need for phototherapy, respiratory distress syndrome, meconium aspiration syndrome, need for mechanical ventilation support, necrotizing enterocolitis, intraventricular hemorrhage, hypoxic ischemic encephalopathy, periventricular leukomalacia, seizures, hypoglycemia, hypothermia, and death. Continuous parameters were compared with Anova's test or Kruskal Wallis, and categorical variables by chi-square test or Fisher exact test, as appropriate. Multivariant logistic regression was performed in order to eliminate possible cofounders.

RESULTS

Overall, 24,445 deliveries were reviewed (C-20,185, LM-1074, IM-2736, HM-450). Composite adverse neonatal outcome was more common with increasing thickness of MSAF. On multivariable analysis, IM and HM were independently associated with composite adverse neonatal outcome.

CONCLUSION

The degree of meconium thickness independently correlates with composite adverse neonatal outcome.

Tracheal suctioning of meconium at birth for non-vigorous infants: a systematic review and meta-analysis

CONTEXT

The International Liaison Committee on Resuscitation sought to review the initial management of non-vigorous newborns delivered through meconium stained amniotic fluid (MSAF).

OBJECTIVE

To complete a systematic review and meta-analysis comparing endotracheal intubation and suctioning to immediate resuscitation without intubation for non-vigorous infants born at ≥34 weeks gestation delivered through MSAF.

DATA SOURCES

Medline, EMBASE, the Cochrane Database of Systematic Reviews, and other registries were searched from 1966 to November 7, 2019.

STUDY SELECTION

Studies were selected by pairs of independent reviewers in 2 stages.

DATA EXTRACTION

Reviewers extracted data, appraised risk of bias, and assessed Grading of Recommendations Assessment, Development and Evaluation certainty of evidence for each outcome.

RESULTS

Four randomized controlled trials (RCTs) included 581 patients and one observational study included 231 patients. No significant differences were observed between the group treated with tracheal suctioning compared with immediate resuscitation for survival at discharge (4 RCTs; risk ratio [RR] = 1.01; 95 % CI, 0.96-1.06; p = 0.69; observational study; no deaths), hypoxic ischemic encephalopathy and meconium aspiration syndrome.

LIMITATIONS

The certainty of evidence was low for survival at discharge and very low for all other outcomes.

CONCLUSIONS

For non-vigorous newborns delivered through MSAF, there is insufficient evidence to suggest routine immediate direct laryngoscopy with tracheal suctioning.

PROSPERO

CRD42019122778.

CLINICAL TRIALS REGISTRATION

PROSPERO; CRD42019122778.

Impact of meconium consistency on infant resuscitation and respiratory outcomes: a retrospective-cohort study and systematic review

Objective: To compare short-term outcomes of infants born with thick versus thin meconium stained amniotic fluid (MSAF) and to perform a systematic review of the topic.Methods: A retrospective, single center, cohort study of infants' ≥34 weeks' gestation born with MSAF between 1 June 2013 and 30 September 2016. Birth resuscitation and respiratory outcomes were compared between the groups. A systematic review was conducted of similar studies published between 1 January 2000 and 30 June 2019.Results: 1507 infants were eligible; 464 (30.8%) thick, 1,043 (69.2%) thin MSAF. The thick group required more respiratory support at birth and was 5.5-fold (95% CI: 2.51-11.95) more likely to and have meconium aspiration syndrome (MAS) and 2.1-fold more likely (95% CI: 0.89-4.83) to require either noninvasive respiratory support or intubation than the thin group. The thick group also had significantly higher oxygen supplementation >24 h (p < .001) and pneumothorax (p = .002). Across 12 studies included in the systematic review, infants with thick MSAF required more intensive birth resuscitation, ventilation support, with higher incidences of MAS. Study differences prohibited data comparisons and quantitative outcome evaluations.Conclusion: Infants with thick MSAF required more intensive birth resuscitation and ventilation support. Our findings need confirmation in robust, prospective cohort studies.

Effectiveness of high-frequency oscillatory ventilation for the treatment of neonatal meconium aspiration syndrome

BACKGROUND

The purpose of this study is to raise nonjudgmental awareness and attention to current experience of high-frequency oscillatory ventilation (HFOV) for the treatment of neonatal meconium aspiration syndrome (NMAS).

METHODS

We will comprehensively search literature from the databases of Cochrane Library, PubMed, Embase, Web of Science, WorldSciNet, PsycINFO, Allied and Complementary Medicine Database, Chinese Biomedical Literature Database, and China National Knowledge Infrastructure from inception until July 1, 2019 without language limitation. We will also handle searching the bibliographies of all relevant studies found for unpublished literatures. Statistical analysis will be conducted using RevMan 5.3 software.

RESULTS

The outcomes include function inhaled oxygen concentration, oxygenation index, arterial oxygen tension/alveolar arterial oxygen tension, partial pressure of oxygen, partial pressure of carbon dioxide, transcutaneous arterial oxygen saturation, duration of hospitalization, and adverse events.

CONCLUSION

This study will provide an exhaustive view of HFOV for treating infants with NMAS.

PROSPERO REGISTRATION NUMBER

PROSPERO CRD42019140520.

Meconium aspiration syndrome: Incidence and outcomes using discharge data

BACKGROUND

Meconium aspiration syndrome (MAS) is a leading cause of morbidity and mortality among term, otherwise healthy newborns, yet population studies are rare. Definitions, outcomes and International Classification of Diseases (ICD) codes are heterogenous, complicating estimates of incidence, outcomes and risks.

AIMS

To measure population incidence, risks and outcomes of MAS by ICD codes.

STUDY DESIGN

Retrospective population study.

SUBJECTS

Kids Inpatient Database (KID) 2012, a nationally representative weighted sample of newborn discharges in the United States.

OUTCOME MEASURES

Incidence, demographic distribution, and comorbidity associated with MAS.

RESULTS

In 2012 there were 9295 weighted discharges diagnosed MAS with symptoms (2.49/1000) and 4304 cases without symptoms (1.15/1000). Newborns with symptoms had nearly twice the length of stay (LOS) (6.68 vs 3.65 days, p 0.001) and nearly 3 times the total charges ($44,473 versus $15,461, p < 0.001) as those without symptoms. Incidence of death was over four times higher (7.7/1000 vs 1.7/1000, p < 0.001), persistent pulmonary hypertension 3 times higher (57.6/1000 vs 15.8/1000, p < 0.001), and hypoxic ischemic encephalopathy 5 times higher (6.2/1000 vs 1.2/1000, p < 0.001) among MAS cases with respiratory symptoms than MAS cases without respiratory symptoms. Odds ratio of MAS with symptoms was 1.54 (95% CI 1.39-1.73) for black newborns compared to whites.

CONCLUSIONS

Discharge data are useful for providing population estimates of MAS incidence. Prior studies have used consolidated ICD codes for MAS (with and without respiratory symptoms), yet these represent very different disease severities. Combining MAS diagnoses with and without respiratory symptoms misrepresents incidence and disease severity, complicating comparisons of outcomes and prevention strategies.

Meconium-stained amniotic fluid: a risk factor for postpartum hemorrhage

Background/aim

Clinical data with respect to the impact of meconium on the risk of maternal hemorrhage are scarce. Therefore, in this study, we aimed to determine whether meconium-stained amniotic fluid (MSAF) represents a risk factor for postpartum hemorrhage (PPH) after vaginal delivery in a large unselected population.

Patients and methods

A retrospective cohort study evaluated 78,542 consecutive women who had a vaginal delivery between 24th and 44th weeks of gestation. The women who had undergone cesarean section were excluded to avoid possible bias. Postpartum blood loss was measured with graduated blood sack. Postpartum blood loss between 1,000 and 2,000 mL and >2,000 mL were classified as moderate and severe PPH, respectively.

Results

A total of 74,144 patients were available for analysis. According to the color of amniotic fluid (AF), two groups of patients were identified: MSAF (n=10,997) and clear AF (n=63,147). The rates of severe and massive PPH were found to be significantly higher in the MSAF group than that of clear AF group (OR=1.3, 95% CI: 1.2-1.5, p<0.001 and OR=2.5, 95% CI: 1.5-4.2, p<0.001). Operative vaginal delivery rate was found to be higher in the MSAF group than that of clear AF group, but the difference was only borderline significant (OR=1.5, 95% CI: 1.0-2.2, p=0.05). There were no significant differences between the MSAF and the clear AF groups with respect to episiotomies, second- or third-degree perineal tears, vaginal-perineal thrombus, cervical lacerations, vaginal births after cesarean section, twin deliveries, and placental retention rates.

Conclusion

To the best of our knowledge, this is the first clinical study that has investigated the role of MSAF as a risk factor for PPH after vaginal delivery in an unselected population. Our results suggest that MSAF is significantly associated with higher risk of moderate and severe PPH than clear AF.

Effect of Gastric Lavage on Meconium Aspiration Syndrome and Feed Intolerance in Vigorous Infants Born with Meconium Stained Amniotic Fluid - A Randomized Control Trial

OBJECTIVE

To compare the incidence of meconium aspiration syndrome and feed intolerance in infants born through meconium stained amniotic fluid with or without gastric lavage performed at birth.

SETTING

Neonatal unit of a teaching hospital in New Delhi, India.

DESIGN

Parallel group unmasked randomized controlled trial.

PARTICIPANTS

700 vigorous infants of gestational age ≥34 weeks from through meconium stained amniotic fluid.

INTERVENTION

Gastric lavage in the labor room with normal saline at 10 mL per kg body weight (n=350) or no gastric lavage (n=350). Meconiumcrit was measured and expressed as ≤30% and >30%.

OUTCOME MEASURES

Meconium aspiration syndrome, feed intolerance and procedure-related complications during 72 h of observation.

RESULTS

5 (1.4%) infants in lavage group and 8 (2.2%) in no lavage group developed meconium aspiration syndrome (RR 0.63, 95% CI 0.21, 1.89). Feed intolerance was observed in 37 (10.5%) and 53 infants (15.1%) in lavage and no lavage groups, respectively (RR 0.70, 95% CI 0.47, 1.03). None of the infants in either group developed apnea, bradycardia or cyanosis during the procedure.

CONCLUSIONS

Gastric lavage performed in the labor room does not seem to reduce either meconium aspiration syndrome or feed intolerance in vigorous infants born through meconium stained amniotic fluid.

Effect of Nasal Continuous Positive Airway Pressure on Infants With Meconium Aspiration Syndrome: A Randomized Clinical Trial

IMPORTANCE

Nasal continuous positive airway pressure (NCPAP) as a primary respiratory therapy in meconium aspiration syndrome (MAS) has not been studied extensively. Nasal continuous positive airway pressure, when applied in newborns with MAS, may resolve atelectasis by sufficiently expanding partially obstructed small airways and stabilizing the collapsing terminal airways to enhance oxygen exchange.

OBJECTIVE

To compare NCPAP vs standard care in neonates with moderate to severe respiratory failure due to MAS in reducing the need for invasive ventilation.

DESIGN, SETTINGS, AND PARTICIPANTS

This multicenter open-label, parallel-group (1:1 ratio) randomized clinical trial was conducted from August 5, 2014, to May 26, 2016. Data were collected from 3 tertiary care neonatal intensive care units. All infants admitted with respiratory distress, defined as Downe score greater than 4 and peripheral capillary oxygen saturation less than 90%, were assessed for study eligibility if the chest radiograph was suggestive of MAS and they met the other inclusion criteria: gestation longer than 35 weeks, a birth weight greater than 2000 g, and born through meconium-stained amniotic fluid.

INTERVENTIONS

Infants were randomly assigned to either NCPAP or standard care (5-10 L/min hood oxygen).

MAIN OUTCOMES AND MEASURES

The primary outcome was the need for mechanical ventilation in the first 7 days of life.

RESULTS

After excluding 14 infants, 67 infants were randomized to bubble NCPAP and 68 infants to standard care. Baseline characteristics were similar between the 2 groups. Infants randomized to the bubble NCPAP group needed mechanical ventilation less frequently in the first 7 days of life compared with standard care (2 [3.0%] vs 17 [25.0%]); odds ratio, 0.09; 95% CI, 0.02-0.43; P = .002). The need for surfactant (3 [4.5%] vs 11 [16.2%]; odds ratio, 0.24; 95% CI, 0.05-0.87) and culture-positive sepsis (4 [6.0%] vs 13 [19.0%]; odds ratio, 0.28; 95% CI, 0.09-0.93) were higher in the standard care group. There was an increased duration of oxygen therapy (median [interquartile range], 45.5 [28.0-78.3] vs 26 [20.0-48.0] hours; P = .001) in the standard care group. In the NCPAP group vs standard care group, incidence of persistent pulmonary hypertension (9 [13%] vs 19 [28%]; odds ratio, 0.42; 95% CI, 0.17-1.01) and duration of hospital stay (median [interquartile range], 5.0 [4.0-8.8] vs 4.0 [4.0-6.0] days; P = .14) were similar.

CONCLUSIONS AND RELEVANCE

Bubble NCPAP in comparison with standard care for infants with MAS reduces the need for mechanical ventilation in the first 7 days of life.

TRIAL REGISTRATION

Clinical Trial Registry, India Identifier: CTRI/2015/03/005631.

Respiratory distress in term neonates in low-resource settings

Most neonatal deaths worldwide occur in low- and middle-income countries (LMICs). Respiratory distress is an important cause of neonatal morbidity and mortality. The epidemiology of respiratory distress among term neonates who constitute the vast majority of births is under reported. The scarcely available data from LMICs suggest an incidence of 1.2% to 7.2% among term live births and greater morbidity compared to that in high-income countries. Pneumonia and meconium aspiration syndrome are the predominant causes among outborn neonates, but next only to transient tachypnea among inborn neonates. Community management of neonatal sepsis/pneumonia using simplified antibiotic regimens when referral is not feasible, implementation of non-invasive ventilation, and innovative low-cost technologies to deliver respiratory therapy are important advances that have taken place in these settings. There is an urgent need to generate data on respiratory morbidities among term neonates so that the limited resources in these settings can be allocated judiciously.

Restoring pulmonary surfactant membranes and films at the respiratory surface

Pulmonary surfactant is a complex of lipids and proteins assembled and secreted by the alveolar epithelium into the thin layer of fluid coating the respiratory surface of lungs. There, surfactant forms interfacial films at the air-water interface, reducing dramatically surface tension and thus stabilizing the air-exposed interface to prevent alveolar collapse along respiratory mechanics. The absence or deficiency of surfactant produces severe lung pathologies. This review describes some of the most important surfactant-related pathologies, which are a cause of high morbidity and mortality in neonates and adults. The review also updates current therapeutic approaches pursuing restoration of surfactant operative films in diseased lungs, mainly through supplementation with exogenous clinical surfactant preparations. This article is part of a Special Issue entitled: Membrane Lipid Therapy: Drugs Targeting Biomembranes edited by Pablo V. Escribá.

Meconium aspiration syndrome: a role for fetal systemic inflammation

BACKGROUND

Meconium aspiration syndrome (MAS) is a leading cause of morbidity and mortality in term infants. Meconium-stained amniotic fluid (MSAF) occurs in approximately 1 of every 7 pregnancies, but only 5% of neonates exposed to MSAF develop MAS. Why some infants exposed to meconium develop MAS while others do not is a fundamental question. Patients with MSAF have a higher frequency of intraamniotic inflammation/infection than those with clear fluid. We propose that fetal systemic inflammation is a risk factor for the development of MAS in patients with MSAF.

OBJECTIVE

We sought to investigate whether intraamniotic inflammation and funisitis, the histopathologic landmark of a fetal inflammatory response, predispose to MAS.

STUDY DESIGN

A prospective cohort study was conducted from 1995 through 2009. Amniotic fluid (AF) samples (n = 1281) were collected at the time of cesarean delivery from women who delivered singleton newborns at term (gestational age ≥38 weeks). Intraamniotic inflammation was diagnosed if the AF concentration of matrix metalloproteinase-8 was >23 ng/mL. Funisitis was diagnosed by histologic examination if inflammation was present in the umbilical cord.

RESULTS

The prevalence of MSAF was 9.2% (118/1281), and 10.2% (12/118) of neonates exposed to MSAF developed MAS. There were no significant differences in the median gestational age or umbilical cord arterial pH at birth between neonates who developed MAS and those who did not (each P > .1). Mothers whose newborns developed MAS had a higher median of AF matrix metalloproteinase-8 (456.8 vs 157.2 ng/mL, P < .05). Newborns exposed to intraamniotic inflammation had a higher rate of MAS than those who were not exposed to intraamniotic inflammation [13.0% (10/77) vs 0% (0/32), P = .03], as did those exposed to funisitis [31.3% (5/16) vs 7.3% (6/82); relative risk, 4.3; 95% confidence interval, 1.5-12.3]. Among the 89 newborns for whom both AF and placental histology were available, MAS was more common in patients with both intraamniotic inflammation and funisitis than in those without intraamniotic inflammation and funisitis [28.6% (4/14) vs 0% (0/28), P = .009], while the rate of MAS did not show a significant difference between patients with intraamniotic inflammation alone (without funisitis) and those without intraamniotic inflammation and funisitis [10.9% (5/46) vs 0% (0/28)].

CONCLUSION

The combination of intraamniotic inflammation with fetal systemic inflammation is an important antecedent of MAS. This concept has implications for the understanding of the mechanisms of disease responsible for MAS and for the development of prognostic models and therapeutic interventions for this disorder.

Endotracheal Suction for Nonvigorous Neonates Born through Meconium Stained Amniotic Fluid: A Randomized Controlled Trial

OBJECTIVE

To assess whether endotracheal suctioning of nonvigorous infants born through meconium stained amniotic fluid (MSAF) reduces the risk and complications of meconium aspiration syndrome (MAS).

STUDY DESIGN

Term, nonvigorous babies born through MSAF were randomized to endotracheal suction and no-suction groups (n=61 in each). Risk of MAS, complications of MAS and endotracheal suction, mortality, duration of neonatal intensive care unit stay, and neurodevelopmental outcome at 9 months were assessed.

RESULTS

Maternal age, consistency of meconium, mode of delivery, birth weight, sex, and Apgar scores were similar in the groups. In total, 39 (32%) neonates developed MAS and 18 (14.8%) of them died. There were no significant differences in MAS, its severity and complications, mortality, and neurodevelopmental outcome for the 2 groups. One infant had a complication of endotracheal suctioning, which was mild and transient.

CONCLUSIONS

The current practice of routine endotracheal suctioning for nonvigorous neonates born through MSAF should be further evaluated.

TRIAL REGISTRATION

Clinical Trial Registry of India: CTRI/2013/03/003469.

Pulmonary hypertension in chronic lung disease of infancy

PURPOSE OF REVIEW

Advances in neonatal care have improved the survival of extremely preterm infants. Chronic lung disease (CLD) is a common complication of prematurity, seen in about a third of preterm babies. Further, pulmonary hypertension complicates the hospital course in about 18% of preterm infants, and the incidence is much higher in infants with established CLD. There is increasing interest in studying this population and understanding the underlying pathobiology behind the development of pulmonary hypertension, which could lead to better identification of at-risk patients as well as improved management strategies and therapeutic targets.

RECENT FINDINGS

Acknowledgement of this growing population of infants with pulmonary hypertension has led to modifications in the current WHO classification of pulmonary hypertension and the establishment of a subcategory for developmental lung disease with pulmonary hypertension. A number of recent publications have evaluated the use of targeted therapies in this population; however, there is a need for large controlled studies, to study the long-term efficacy and safety of these medications.

SUMMARY

This review will discuss the pathobiology of CLD with pulmonary hypertension and enumerate the current diagnostic and treatment modalities used by experts in the field. It will also suggest a diagnosis and management algorithm for infants suspected to have pulmonary hypertension in the newborn unit.

Acute Neonatal Respiratory Failure

Acute respiratory failure requiring assisted ventilation is one of the most common reasons for admission to the neonatal intensive care unit. Respiratory failure is the inability to maintain either normal delivery of oxygen to the tissues or normal removal of carbon dioxide from the tissues. It occurs when there is an imbalance between the respiratory workload and ventilatory strength and endurance. Definitions are somewhat arbitrary but suggested laboratory criteria for respiratory failure include two or more of the following: PaCO₂ > 60 mmHg, PaO₂ < 50 mmHg or O₂ saturation <80 % with an FiO₂ of 1.0 and pH < 7.25 (Wen et al. 2004).

Perinatal asphyxia associated with early neonatal mortality: populational study of avoidable deaths

OBJECTIVE

To compare the epidemiological profile of avoidable early neonatal deaths associated with perinatal asphyxia according to region of death in the State of São Paulo, Brazil.

METHODS

Population-based cohort study including 2,873 avoidable deaths up to six days of life associated with perinatal asphyxia from January 2001 to December 2003. Perinatal asphyxia was considered if intrauterine hypoxia, birth asphyxia, or meconium aspiration syndrome were written in any line of the original Death Certificate. Epidemiological data were also extracted from the Birth Certificate.

RESULTS

During the three years, 1.71 deaths per 1,000 live births were associated with perinatal asphyxia, which corresponded to 22% of the early neonatal deaths. From the 2,873 avoidable deaths, 761 (27%) occurred in São Paulo city; 640 (22%), in the metropolitan region of São Paulo city; and 1,472 (51%), in the countryside of the state. In the first two regions, deaths were more frequent in public hospitals, among newborns with gestational age of 36 weeks or less, and among babies weighing less than 2500g. In the countryside, mortality was more frequent in philanthropic hospitals, in term newborns and in neonates weighing over 2500g. Most of these neonates were born during daytime in their hometown and died at the same institution in which they were born within the first 24 hours after delivery. Meconium aspiration syndrome was related to 18% of the deaths.

CONCLUSIONS

Perinatal asphyxia is a frequent contributor to the avoidable early neonatal death in the state with the highest gross domestic product per capita in Brazil, and it shows the need for specific interventions with regionalized focus during labor and birth care.

Respiratory distress including meconium aspiration syndrome in vigorous neonates born through meconium stained amniotic fluid: incidence, onset, severity and predictors at birth

OBJECTIVE

This study aimed to find out incidence, predictors, onset and severity of respiratory distress including meconium aspiration syndrome (MAS) among vigorous neonates born through meconium stained amniotic fluid (MSAF), which may or may not be evident at birth.

METHODS

Two hundred ninety vigorous neonates were studied. Data were collected on perinatal risk factors, clinical course and development of respiratory distress. Predictors of respiratory distress were identified by logistic regression and a score based on adjusted OR was assigned for each. Diagnostic performance of the score (0-24) was assessed on another 247 vigorous neonates using receiver operator characteristic analysis (ROC).

RESULTS

Respiratory distress developed in 97(33.4 %) infants, MAS in 75(25.9 %). The distress appeared within 12 h in 97.9 %, was severe in only 21.7 %. Of 10 risk factors significantly associated with respiratory distress, seven entered in regression analysis. Fetal distress(adj OR = 11.8; 95%CI = 6.2-22.5), prolonged labor(adj OR = 5.2; 95%CI = 2.5-10.7), and absent/poor cry(adj OR = 5.6; 95%CI = 2.4-13.3) were identified as independent predictors; each assigned a score of 12, 6 and 6, respectively. To predict respiratory distress, a cut-off score of 9 points had sensitivity-74.1 % (95%CI = 63.3 %-82.7 %), specificity-84.6 % (95 % CI = 77.9 %-89.6 %), positive predictive value- 71.6 % (95%CI = 60.8 %-80.4 %), negative predictive value- 86.2 % (95 % CI = 79.6 %-90.9 %), likelihood ratio (LR) + ve 4.8(95%CI = 3.3-7.0) and LR-ve 0.3(95%CI = 0.2-0.4).

CONCLUSIONS

Respiratory distress occurred in one third neonates, mostly had onset within 12 h of birth, and it was mild to moderate in majority. Fetal distress, prolonged labor, and absent/poor cry predicted respiratory distress and were validated. However, larger studies in different settings are required to confirm its utility.

Randomized controlled trial of lung lavage with dilute surfactant for meconium aspiration syndrome

OBJECTIVE

To evaluate whether lung lavage with surfactant changes the duration of mechanical respiratory support or other outcomes in meconium aspiration syndrome (MAS).

STUDY DESIGN

We conducted a randomized controlled trial that enrolled ventilated infants with MAS. Infants randomized to lavage received two 15-mL/kg aliquots of dilute bovine surfactant instilled into, and recovered from, the lung. Control subjects received standard care, which in both groups included high frequency ventilation, nitric oxide, and, where available, extracorporeal membrane oxygenation (ECMO).

RESULTS

Sixty-six infants were randomized, with one ineligible infant excluded from analysis. Median duration of respiratory support was similar in infants who underwent lavage and control subjects (5.5 versus 6.0 days, P = .77). Requirement for high frequency ventilation and nitric oxide did not differ between the groups. Fewer infants who underwent lavage died or required ECMO: 10% (3/30) compared with 31% (11/35) in the control group (odds ratio, 0.24; 95% confidence interval, 0.060-0.97). Lavage transiently reduced oxygen saturation without substantial heart rate or blood pressure alterations. Mean airway pressure was more rapidly weaned in the lavage group after randomization.

CONCLUSION

Lung lavage with dilute surfactant does not alter duration of respiratory support, but may reduce mortality, especially in units not offering ECMO.