Neurodevelopmental outcome of infants with meconium aspiration syndrome: report of a study and literature review

Intratracheal instillation of budesonide suspension versus normal saline on oxidative stress in neonates with meconium aspiration syndrome

BACKGROUND

Presently, the efficacy of neonatal resuscitation techniques via interventions such as oral, nasal, and endotracheal suction for preventing meconium aspiration syndrome (MAS) after delivery has not been satisfactory.

OBJECTIVE

This study aimed to investigate the role of intratracheal instillation of budesonide on oxidative stress in MAS.

METHODS

Sixty-two neonates with MAS admitted to Huai'an Maternity and Child Healthcare Hospital from January 2018 to June 2020 were divided into a study group (intratracheal instillation of 2 ml budesonide suspension; n = 31) and a control group (intratracheal instillation of 2 ml normal saline; n = 31). Collect data from two groups of patients and evaluate clinical outcomes, including oxygenation index (OI), as well as serum total oxidant status (TOS), total antioxidant capacity (TAC), oxidative stress index (OSI) and 8-Isoprostane before treatment and 72h after admission.

RESULTS

We found no statistical differences in mortality, complication rate, total oxygen inhalation time, OI before treatment and 72h after admission between the two groups of neonates with MAS, while the duration of invasive respiratory support in the study group was significantly shorter than in the control group. Also, serum TAC, TOS, OSI and 8-isoprostane levels were not statistically different before treatment between the two groups. After 72h of admission, OSI and 8-Isoprostane in neonates with MAS in the study group were much lower than those in the control group. TOS, OSI, 8-Isoprostane in the control group and 8-Isoprostane in the study group were significantly higher than those before treatment. As for TAC and TOS, no significant differences were observed between the two groups.

CONCLUSION

Intratracheal instillation of budesonide was shown to alleviate oxidative stress and shorten invasive ventilation time in neonates with MAS.

Long-Term Pulmonary and Neurodevelopmental Outcomes of Meconium Aspiration Syndrome Affected Infants: A Retrospective National Population-Based Study in Taiwan

INTRODUCTION

Meconium aspiration syndrome (MAS) may cause severe pulmonary and neurologic injuries in affected infants after birth, leading to long-term adverse pulmonary or neurodevelopmental outcomes.

METHODS

This retrospective population-based cohort study enrolled 1,554,069 mother-child pairs between 2004 and 2014. A total of 8,049 infants were in the MAS-affected group, whereas 1,546,020 were in the healthy control group. Children were followed up for at least 3 years. According to respiratory support, MAS was classified as mild, moderate, and severe. With the healthy control group as the reference, the associations between MAS severity and adverse pulmonary outcomes (hospital admission, intensive care unit (ICU) admission, length of hospital stay, or invasive ventilator support during admission related to pulmonary problem) or adverse neurodevelopmental outcomes (cerebral palsy, needs for rehabilitation, visual impairment, or hearing impairment) were accessed.

RESULTS

MAS-affected infants had a higher risk of hospital and ICU admission and longer length of hospital stay, regardless of severity. Infants with severe MAS had a higher risk of invasive ventilator support during re-admission (odds ratio: 17.50, 95% confidence interval [CI]: 7.70-39.75, p < 0.001). Moderate (hazard ratio [HR]: 1.66, 95% CI: 1.30-2.13, p < 0.001) and severe (HR: 4.94, 95% CI: 4.94-7.11, p < 0.001) MAS groups had a higher risk of adverse neurodevelopmental outcome, and the statistical significance remained remarkable in severe MAS group after adjusting for covariates (adjusted HR: 2.28, 95% CI: 1.54-3.38, p < 0.001) Conclusions: Adverse pulmonary or neurodevelopmental outcomes could occur in MAS-affected infants at birth. Close monitoring and follow-up of MAS-affected infants are warranted.

Meconium aspiration syndrome: from pathophysiology to treatment

Meconium aspiration syndrome (MAS) is a clinical condition characterized by respiratory distress in neonates born through meconium-stained amniotic fluid (MSAF). Despite advances in obstetric practices and perinatal care, MAS remains an important cause of morbidity and mortality in term and post-term newborns. Since the 1960s, there have been significant changes in the perinatal and postnatal management of infants born through MSAF. Routine endotracheal suctioning is no longer recommended in both vigorous and non-vigorous neonates with MSAF. Supportive care along with new treatments such as surfactant, inhaled nitric oxide, and high-frequency ventilation has significantly improved the outcome of MAS patients. However, determining the most appropriate approach for this condition continues to be a topic of debate. This review offers an updated overview of the epidemiology, etiopathogenesis, diagnosis, management, and prognosis of infants with MAS.

Meconium aspiration syndrome: a comprehensive review

Meconium aspiration syndrome (MAS) is a complex respiratory disease that continues to be associated with significant morbidities and mortality. The pathophysiological mechanisms of MAS include airway obstruction, local and systemic inflammation, surfactant inactivation and persistent pulmonary hypertension of the newborn (PPHN). Supplemental oxygen and non-invasive respiratory support are the main therapies for many patients. The management of the patients requiring invasive mechanical ventilation could be challenging because of the combination of atelectasis and air trapping. While studies have explored various ventilatory modalities, evidence to date does not clearly support any singular modality as superior. Patient's pathophysiology, symptom severity, and clinician/unit expertise should guide the respiratory management. Early identification and concomitant management of PPHN is critically important as it contributes significantly to mortality and morbidities.

Efficacy of synthetic surfactant (CHF5633) bolus and/or lavage in meconium-induced lung injury in ventilated newborn rabbits

BACKGROUND

The pathogenesis of neonatal meconium aspiration syndrome (MAS) involves meconium-induced lung inflammation and surfactant inactivation. Bronchoalveolar lavage (BAL) with diluted surfactant facilitates the removal of meconium. CHF5633, one of the most promising synthetic surfactants, is effective in neonatal respiratory distress syndrome. Here we investigated its efficacy via BAL in an experimental MAS model.

METHODS

Experimental MAS was induced at birth in near-term newborn rabbits by intratracheal instillation of reconstituted human meconium. First, undiluted CHF5633 was compared with a porcine-derived surfactant (Poractant alfa) via intratracheal bolus (200 mg/kg). Second, the efficacy of BAL with diluted CHF5633 (5 mg/mL, 20 ml/kg) alone, or followed by undiluted boluses (100 or 300 mg/kg), was investigated.

RESULTS

Meconium instillation caused severe lung injury, reduced endogenous surfactant pool, and poor survival. CHF5633 had similar benefits in improving survival and alleviating lung injury as Poractant alfa. CHF5633 BAL plus higher boluses exerted better effects than BAL or bolus alone in lung injury alleviation by reversing phospholipid pools and mitigating proinflammatory cytokine mRNA expression, without fluid retention and function deterioration.

CONCLUSIONS

CHF5633 improved survival and alleviated meconium-induced lung injury, the same as Poractant alfa. CHF5633 BAL plus boluses was the optimal modality, which warrants further clinical investigation.

IMPACT

To explore the efficacy of a synthetic surfactant, CHF5633, in neonatal lung protection comparing with Poractant alfa in a near-term newborn rabbit model with meconium-induced lung injury. Similar effects on improving survival and alleviating lung injury were found between CHF5633 and Poractant alfa. Optimal therapeutic effects were identified from the diluted CHF5633 bronchoalveolar lavage followed by its undiluted bolus instillation compared to the lavage or bolus alone regimens. Animals with CHF5633 lavage plus bolus regimen exerted neither substantial lung fluid retention nor lung mechanics deterioration but a trend of higher pulmonary surfactant-associated phospholipid pools.

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.

Long term outcome of babies with pulmonary hypertension

Neonatal pulmonary hypertension (PH) is associated with many severe congenital abnormalities (congenital diaphragmatic hernia) or acquired cardiorespiratory diseases such as pneumonia, meconium aspiration and bronchopulmonary dysplasia (BPD). If no cause is found it may be labelled idiopathic persistent pulmonary hypertension of the newborn. Although PH may result in life threatening hypoxia and circulatory failure, in the majority of cases, it resolves in the neonatal period following treatment of the underlying cause. However, in some cases, neonatal PH progresses into infancy and childhood where symptoms include failure to thrive and eventually right heart failure or death if left untreated. This chronic condition is termed pulmonary vascular hypertensive disease (PHVD). Although classification and diagnostic criteria have only recently been proposed for pediatric PHVD, little is known about the pathophysiology of chronic neonatal PH, or why pulmonary vascular resistance may remain elevated well beyond infancy. This review explores the many factors involved in chronic PH and what implications this may have on long term outcome when the disease progresses beyond the neonatal period.

Exposure to Meconium-Stained Amniotic Fluid and Long-Term Neurological-Related Hospitalizations throughout Childhood

OBJECTIVE

This study aimed to investigate the possible impact of meconium-stained amniotic fluid (MSAF) on the occurrence of neurological-related hospitalizations throughout childhood and adolescence.

STUDY DESIGN

In this population-based cohort analysis, all singleton deliveries occurring between 1991 and 2014 at the Soroka University Medical center were included and the long-term neurological-related hospitalizations were compared between children with and without MSAF during their delivery. A Kaplan-Meier survival analysis was constructed for the evaluation of cumulative hospitalization rate due to neurological morbidity over the 18 years of follow-up, and a Cox proportional hazards model was used to study the independent association between MSAF and childhood neurological morbidity while controlling for potential confounders.

RESULTS

During the study period, 243,725 deliveries met the inclusion criteria; 35,897 of the cohort (15%) constituted the exposed group (MSAF), while the rest of the cohort (n = 207,828) constituted the unexposed group (no MSAF). A total of 7,543 hospitalizations due to neurological-related morbidity were documented with a rate of 3.2% (1,152) in children exposed to MSAF as compared with 3.1% (6,391) in the unexposed group (OR 1.1, 95% confidence interval 0.9-1.1, p = 0.149). The survival curve showed a comparable cumulative hospitalization rate in the MSAF-exposed group compared with the unexposed group (log rank p = 0.349). The Cox analysis, controlled for gestational diabetes and hypertension, gestational and maternal ages, demonstrated MSAF exposure not to be an independent risk factor for neurological-related hospitalizations during childhood (adjusted hazard ratio = 1.03, 0.96-1.09).

CONCLUSION

Fetal exposure to MSAF, at any gestational age, does not appear to be an independent risk factor for later neurological-related hospitalizations throughout childhood and adolescence.

KEY POINTS

· MSAF is associated with several short-term complications such as low Apgar scores.. · The long-term implications of MSAF exposure are yet to be clearly defined.. · Fetal exposure to MSAF is not a risk factor for neurological morbidity throughout childhood..

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).

Meconium stained amniotic fluid exposure and long-term respiratory morbidity in the offspring

OBJECTIVE

Meconium stained amniotic fluid (MSAF) is a well-established risk factor for neonatal short-term respiratory complications. Little is known regarding the long-term morbidity. We investigated the possible association between MSAF and offspring respiratory morbidity.

METHODS

A population-based, cohort study of singleton deliveries occurring between 1991 and 2014 at a sole regional tertiary medical center was performed. Incidence of offspring respiratory related hospitalizations up to the age of 18 years were evaluated and compared to unexposed offspring. A Kaplan-Meier survival curve was used to compare cumulative respiratory morbidity incidence, and a Cox proportional hazards model was used to control for confounders.

RESULTS

During the study period 242,342 deliveries met the inclusion criteria. Of them, 14.7% (n = 35,609) were complicated with MSAF. Incidence of respiratory-related hospitalizations was significantly lower in children exposed to MSAF as compared to the unexposed group (4.5% vs. 4.9%, respectively; p < .01). Specifically, hospitalizations involving pneumonitis were significantly less common among the MSAF group (odds ratio, 0.35; 95% confidence interval [95% CI], 0.13-0.96; p = .03). The Kaplan-Meier survival curve demonstrated significantly lower total cumulative respiratory morbidity rates in the MSAF exposed group (log rank p < .01). In the Cox model, controlled for clinically relevant confounders, MSAF exhibited an independent and significant protective effect on long-term childhood respiratory morbidity (aHR, 0.91; 95% CI, 0.86-0.96; p < .01).

CONCLUSIONS

Fetal exposure to MSAF during labor appears to be associated with lower rates of long-term respiratory related hospitalizations in the offspring. Changes in offspring microbiome, as well as functional and anatomical modulations possibly resulting from MSAF exposure, might offer a plausible explanation of our findings.

Is meconium exposure associated with autism spectrum disorders in children?

BACKGROUND

The results differ among published studies regarding exposure to meconium and the risk of developing autism spectrum disorders (ASDs).

PURPOSE

The present study pooled all of the epidemiologic studies retrieved from broader databases on the association between meconium exposure and risk of developing ASD in children.

METHODS

The Web of Science, PubMed, Scopus, and Google Scholar databases were searched without language restrictions for articles published between their inception to February 20, 2020, using relevant keywords. The pooled odds ratios (ORs) and their 95% confidence intervals (CIs) were calculated as random-effect estimates of the associations among studies. A subgroup analysis was conducted to explore any potential sources of heterogeneity among studies.

RESULTS

The pooled estimate of OR reported a weakly significant association between meconium exposure and ASD development in children (OR, 1.13; 95% CI, 1.03-1.24). There was low heterogeneity among the articles reporting risk for ASD among children (I2=19.3%; P=0.259). The results of subgroup analysis based on meconium exposure showed a significant association between a meconium-stained neonate and ASD development (OR, 1.18; 95% CI, 1.11-1.24).

CONCLUSION

Meconium exposure was weakly associated with an increased risk of ASD. However, more evidence based on large prospective cohort studies is required to provide conclusive evidence about whether meconium exposure is associated with an increased risk of ASD development.

Meconium Aspiration Syndrome: A Narrative Review

Meconium aspiration syndrome is a clinical condition characterized by respiratory failure occurring in neonates born through meconium-stained amniotic fluid. Worldwide, the incidence has declined in developed countries thanks to improved obstetric practices and perinatal care while challenges persist in developing countries. Despite the improved survival rate over the last decades, long-term morbidity among survivors remains a major concern. Since the 1960s, relevant changes have occurred in the perinatal and postnatal management of such patients but the most appropriate approach is still a matter of debate. This review offers an updated overview of the epidemiology, etiopathogenesis, diagnosis, management and prognosis of infants with meconium aspiration syndrome.

The risk of meconium aspiration syndrome (MAS) increases with gestational age at term

Objective: To examine the risk of meconium aspiration syndrome (MAS) by the week of gestational age in pregnancies with meconium-stained amniotic fluid (MSAF).Methods: This is a retrospective cohort study derived from term pregnancies at a single tertiary institution over an 18-year period. Outcomes analyzed included MAS, acidemia, and Apgar scores. Univariate analysis was performed using chi-square and multivariable logistic regression was used to adjust for potential confounders.Results: A total of 34,303 deliveries ≥37 weeks were included; 23.7% were complicated by MSAF. Of the total study cohort, 272 (0.7%) neonates were diagnosed with MAS; this represented 3% of all deliveries complicated by MSAF. In the presence of MSAF, the risk of MAS increased with gestational age, from 1.3% at 38 weeks to 4.8% at 42 weeks (p < .001). Similarly, the risk of acidemia increased from 3.0% at 38 weeks to 7.0% at 42 weeks (p < .001). These findings were also demonstrated in patients with MAS in the absence of MSAF. The risk for both MAS and acidemia in the presence of MSAF persisted after controlling for potential confounders (aOR 1.31 [95% CI 1.18-1.46] and 1.20 [95% CI 1.05-1.37], respectively).Conclusion: In women with MSAF, as gestational age increases, the risk of meconium aspiration syndrome also increases. Other factors with late-term and post-term pregnancy besides the presence of meconium may contribute to the evolution of MAS.

Identifying Aspiration Among Infants in Neonatal Intensive Care Units Through Occupational Therapy Feeding Evaluations

IMPORTANCE

When a neonate's sucking, swallowing, and breathing are disorganized, oropharyngeal aspiration often occurs and results in illness, developmental problems, and even death. Occupational therapists who work in the neonatal intensive care unit (NICU) need to identify neonates who are at risk for aspirating so they can provide appropriate treatment.

OBJECTIVE

To ascertain whether client factors and performance skills of infants ages 0-6 mo during occupational therapy feeding evaluations are related to results of videofluoroscopic swallowing studies (VFSSs).

DESIGN

Retrospective chart reviews.

SETTING

187-bed NICU in a nonprofit teaching hospital.

PARTICIPANTS

A purposive sample of 334 infants ages 0-6 mo, ≥33 wk gestational age at birth, admitted to a Level II, III, or IV NICU as defined by the American Academy of Pediatrics.

OUTCOMES AND MEASURES

Neonates were administered a feeding evaluation by an occupational therapist and a VFSS by a speech-language pathologist, which yielded information about client factors and performance skills.

RESULTS

Signs and symptoms of aspiration on the evaluations were significantly associated with VFSS results. Of 310 patients, 79 had silent aspiration. Of 55 infants who demonstrated no aspiration symptoms during the feeding evaluation, 45% demonstrated aspiration symptoms on the VFSS, and 55% aspirated on the VFSS but demonstrated no symptoms of aspiration.

CONCLUSIONS AND RELEVANCE

Aspiration among infants occurs inconsistently and depends on client factors, contexts, and environments. Occupational therapists are encouraged to assess an infant's feeding over several sessions to obtain a more accurate picture of the infant's feeding status.

WHAT THIS ARTICLE ADDS

This study provides information that helps occupational therapists identify infants at risk for aspiration and make optimal recommendations regarding safe feeding practices and appropriate referrals for a VFSS. Making appropriate referrals for VFSS is also important in preventing unnecessary exposure to radiation for preterm infants.

Meconium-stained amniotic fluid exposure is associated with a lower incidence of offspring long-term infectious morbidity

OBJECTIVE

Meconium-stained amniotic fluid (MSAF) is a well-established risk factor for immediate adverse neonatal outcomes and was recently suggested to be associated with microbial invasion of the amniotic cavity. We aimed to determine whether MSAF exposure during labor carries a longer lasting impact on pediatric infectious morbidity.

STUDY DESIGN

A population-based cohort analysis was performed including all singleton deliveries occurring between 1991 and 2014 at a single tertiary medical center. Exposure was defined as the presence of MSAF during labor. Hospitalizations of the offspring up to the age of 18 years involving infectious diseases were evaluated. A Kaplan-Meier survival curve was used to compare cumulative morbidity and a Cox regression model to control for confounders.

RESULTS

During the study period, 243 725 deliveries met the inclusion criteria. Of them, 35 897 (14.7%) involved MSAF. Rate of infectious-related hospitalizations of the offspring was significantly lower in children exposed to MSAF as compared with the unexposed group (10.8% vs 11.1%, P < 0.05). Specifically, hospitalizations involving respiratory infections were significantly less common among the MSAF group (5.1% vs 5.6%, P < 0.001). The survival curve demonstrated significantly lower cumulative total infectious morbidity rates in the MSAF-exposed group (log rank P < 0.001). In the Cox model, controlled for maternal age, diabetes, hypertension, mode of delivery, and gestational age, exposed children exhibited lower rates of long-term childhood infectious morbidity (adjusted HR 0.96, 95% CI 0.92-0.99, P < 0.001).

CONCLUSION

Fetal exposure to MSAF during labor and delivery appears to be associated with lower rates of long-term infectious-related hospitalizations in the offspring.

Delivery Room Management of Meconium-Stained Newborns and Respiratory Support

: media-1vid110.1542/5839992674001PEDS-VA_2018-1485Video Abstract BACKGROUND AND OBJECTIVES: Recently, the Neonatal Resuscitation Program (NRP) recommended against routine endotracheal suctioning of meconium-stained nonvigorous newborns but suggested resuscitation with positive pressure ventilation. Our purpose is to study the effects of this change in management.

METHODS

In this multicenter cohort study, we compare 130 nonvigorous newborns born during the retrospective 1-year period before the implementation of new NRP guidelines (October 1, 2015, to September 30, 2016) to 101 infants born during the 1-year prospective period after implementation (October 1, 2016, to September 30, 2017).

RESULTS

Endotracheal suctioning was performed predominantly in the retrospective group compared with the prospective group (70% vs 2%), indicating the change in practice. A significantly higher proportion of newborns were admitted to the NICU for respiratory issues in the prospective group compared with the retrospective group (40% vs 22%) with an odds ratio (OR) of 2.2 (95% confidence interval [CI]: 1.2-3.9). Similarly, a significantly higher proportion of infants needed oxygen therapy (37% vs 19%) with an OR of 2.5 (95% CI: 1.2-4.5), mechanical ventilation (19% vs 9%) with an OR of 2.6 (95% CI: 1.1-5.8), and surfactant therapy (10% vs 2%) with an OR of 5.8 (95% CI: 1.5-21.8). There were no differences in the incidence of other outcomes, including meconium aspiration syndrome.

CONCLUSIONS

The recent NRP guideline change was not associated with an increased incidence of meconium aspiration syndrome but was associated with an increased incidence of NICU admissions for respiratory issues. Also, the need for mechanical ventilation, oxygen, and surfactant therapy increased.

Meconium "aspiration" (or respiratory distress associated with meconium-stained amniotic fluid?)

The designation meconium aspiration syndrome (MAS) reflects a spectrum of disorders in infants born with meconium-stained amniotic fluid, ranging from mild tachypnea to severe respiratory distress and significant mortality. The frequency of MAS is highest among infants with post-term gestation, thick meconium, and birth asphyxia. Pulmonary hypertension is an important component in severe cases. Prenatal hypopharyngeal suctioning and postnatal endotracheal intubation and suctioning of vigorous infants are not effective. Intubation and suctioning of non-breathing infants is controversial and needs more investigation. Oxygen, mechanical ventilation, and inhaled nitric oxide are the mainstays of treatment. Surfactant is often used in infants with severe parenchymal involvement. High-frequency ventilation and extracorporeal membrane oxygenation are usually considered rescue therapies.

Meconium exposure and autism risk

OBJECTIVE

This study aims to determine whether fetal meconium passage is associated with autism.

STUDY DESIGN

This retrospective birth cohort analysis of 9 945 896 children born in California 1991 to 2008 linked discharge diagnosis and procedure codes for prenatal stressors, meconium-stained amniotic fluid (MSAF) and meconium aspiration syndrome (MAS) with autism diagnoses for 47 277 children through 2012. We assessed the relative risk of autism by meconium status using logistic regression, adjusting for demographic and clinical features.

RESULTS

Children exposed to meconium (MSAF and MAS) were more likely to be diagnosed with autism in comparison with unexposed children (0.60% and 0.52%, vs 0.47%, respectively). In adjusted analyses, there was a small increase in autism risk associated with MSAF exposure (adjusted relative risk (aRR) 1.18, 95% confidence interval (CI) 1.12 to 1.25), and a marginal association that failed to achieve significance between MAS and autism (aRR 1.08, 95% CI 0.98 to 1.20).

CONCLUSION

Resuscitation of neonates with respiratory compromise from in utero meconium exposure may mitigate long-term neurodevelopmental damage.

"Half a Century of Evolution of Neonatology: A Witness's Story" : Dr. K. C. Chaudhuri Lifetime Achievement Award Oration Delivered at AIIMS, New Delhi on 7th September 2014

Lifetime achievement awards are awarded to recognize contributions during the career of an individual, rather than for a single or multiple contributions of a person in his/her field of specialty. I am highly honored being the recipient of the Dr. K. C. Chaudhuri Lifetime Achiement Award Oration. The award for me is significant for several reasons: First being associated with legendary figure such as Dr. Chaudhuri, secondly being recognized by my fellow Indian colleagues. Finally, it also marks half a century of my experience in development of subspecialty of neonatology in US. Some fifty and odd years ago, as an young novice from India I joined the mainstream of this evolution, thanks to my professors and mentors in US and thanks to America, the land of opportunity. During this odyssey, I met many great men and women of science and intellect, saw great scientific discoveries, many innovations, combined with social changes that led to significant reduction of neonatal mortality rates in the industrialized Western countries. I also saw the "Globalization" of "Modern Neonatology" in which I participated with vigor; thus, improving the newborn care in four corners of the world. I am proud that I had the opportunity to contribute a little to growth of neonatology in US and outside the US. This is the story of my professional life. The message of my life story for the younger generation is : Dream big, never give up your dreams. Hardwork, maintaining your integrity, and honesty are the three precepts that will define your character and you will be rewarded in the long run.

Risk factors differentiating mild/moderate from severe meconium aspiration syndrome in meconium-stained neonates

Objective

The aim of this study was to compare the risk factors associated with mild/moderate meconium aspiration syndrome (MAS) with those associated with severe in meconium-stained term neonates.

Methods

Consecutive singleton term neonates (n=671) with meconium staining at birth from all deliveries (n=14,666) in our institution from January 2006 to December 2012 were included. Both maternal and neonatal variables were examined. Among the study population, for women who underwent the trial of labor (n=644), variables associated with labor were also examined. These variables were compared between the mild/moderate MAS group, the severe MAS group, and the MAS-absent group.

Results

MAS developed in 10.6% (71/671) of neonates with meconium staining at birth. Among the neonates with MAS, 81.7% had mild MAS, 5.6% had moderate MAS, and 12.7% had severe MAS. The presence of minimal variability was significantly increased in both the mild/moderate and the severe MAS groups. The frequencies of nulliparity, fetal tachycardia, and intrapartum fever were significantly increased in the mild/moderate MAS group, but not in the severe MAS group. While a longer duration of the second stage of labor was significantly associated with mild/moderate MAS, severe MAS was associated with a shorter duration of the second stage. Notably, low mean cord pH (7.165 [6.850-7.375]) was significantly associated with mild/moderate MAS, but not with severe MAS (7.220 [7.021-7.407]) compared with the absence of MAS (7.268 [7.265-7.271]).

Conclusion

Our data suggest the development of severe MAS is not simply a linear extension of the same risk factors driving mild/moderate MAS.

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).

Blood lactate level and meconium aspiration syndrome

PURPOSE

Approximately 5% of infants born with a meconium-stained amniotic fluid (MSAF) develop meconium aspiration syndrome (MAS). Early recognition of infants at highest risk for the development of MAS and the prediction of disease severity are important for optimizing the clinical strategies for prevention and treatment. The aim of the present study was to identify the risk factors for MAS and to investigate the effect of blood lactate level on the development of MAS.

METHODS

Between January 2011 and January 2012, data were recorded with regard to gender, mode of delivery, gestational week, birth weight, 5-min Apgar score, and need for resuscitation of the meconium-stained depressed infants who underwent tracheal aspiration. Moreover, the number of cases developing MAS, blood pH value, and lactate level in capillary blood gases obtained during the first hour after delivery, duration of oxygen supplementation, the number of cases receiving mechanical ventilation and surfactant therapy, duration of hospital stay, and outcomes of the infants were recorded.

RESULTS

The number of live births during the study period was 17,202, and of them, 1,341 (7.8%) infants were born through MSAF. Of 195 infants who were meconium-stained depressed, 90 were girls and 105 were boys. Their mean gestational week was 39.37 ± 0.89 weeks and mean birth weight was 3,426 ± 634 g. Eighty-four of them were born through cesarean section (C/S), and 111 were born via normal spontaneous labor. For 40 infants, Apgar score at fifth minute was less than 6. In total, resuscitation was performed on 43 (22.9%) infants. Of the infants, 141 did not develop MAS and 54 developed MAS. While there were no significant differences between infants with and without MAS with regard to gender, delivery route, gestational week, and birth weight, a significant difference was observed regarding the Apgar score (p = 0.0001). The blood pH value in capillary blood gas analysis was less than 7.25 in 18 (28.5%) cases with MAS and four (3.2%) cases without MAS. There was no significant difference between infants with and without MAS with regard to blood pH levels (p = 0.031). The mean blood lactate level was 8.5± 3.4 mmol/L in the patients with MAS, and there was a significant difference between infants with and without MAS regarding blood lactate level (p = 0.0001). The mean duration of oxygen supplementation was 86.62 ± 66.52 and 44.36 ± 19.03 h in patients with MAS and without MAS, respectively. In total, 30 infants required mechanical ventilation (24 infants with MAS and 6 infants without MAS). In addition to mechanical ventilation, 16 infants with MAS were administered surfactant therapy. The mean duration of hospital stay of infants with MAS was significantly higher than infants without MAS (p = 0.0001). There was a correlation between blood lactate levels, blood pH value, and hospitalization duration (p < 0.05). All of the infants, except one patient, were discharged from the NICU.

CONCLUSION

In addition to the blood pH value and 5-min Apgar score, increased blood lactate level may be a risk factor for the development of MAS in infants born with MSAF. This may aid in the early detection of MAS and, with appropriate measures taken sooner, reduce morbidity and mortality. Further studies are needed to elucidate the role of lactate level, which is an important indicator of hypoxia during the development of MAS.

Exogenous surfactant therapy in 2013: what is next? Who, when and how should we treat newborn infants in the future?

Background

Surfactant therapy is one of the few treatments that have dramatically changed clinical practice in neonatology. In addition to respiratory distress syndrome (RDS), surfactant deficiency is observed in many other clinical situations in term and preterm infants, raising several questions regarding the use of surfactant therapy.

Objectives

This review focuses on several points of interest, including some controversial or confusing topics being faced by clinicians together with emerging or innovative concepts and techniques, according to the state of the art and the published literature as of 2013. Surfactant therapy has primarily focused on RDS in the preterm newborn. However, whether this treatment would be of benefit to a more heterogeneous population of infants with lung diseases other than RDS needs to be determined. Early trials have highlighted the benefits of prophylactic surfactant administration to newborns judged to be at risk of developing RDS. In preterm newborns that have undergone prenatal lung maturation with steroids and early treatment with continuous positive airway pressure (CPAP), the criteria for surfactant administration, including the optimal time and the severity of RDS, are still under discussion. Tracheal intubation is no longer systematically done for surfactant administration to newborns. Alternative modes of surfactant administration, including minimally-invasive and aerosolized delivery, could thus allow this treatment to be used in cases of RDS in unstable preterm newborns, in whom the tracheal intubation procedure still poses an ethical and medical challenge.

Conclusion

The optimization of the uses and methods of surfactant administration will be one of the most important challenges in neonatal intensive care in the years to come.

Longitudinal neurodevelopmental evolution in children with severe non-progressive encephalopathy

AIM

The aim of this study was to evaluate the longitudinal neurodevelopmental evolution in children with severe non-progressive encephalopathy.

METHODS

Between 1984 and 2005, 17 patients diagnosed with severe non-progressive encephalopathy under the care of the Institute Provvida Madre underwent neurodevelopmental evaluation on an annual basis for at least five consecutive years using the Munich Functional Developmental Diagnostics (MFDD). The severity of each patient's encephalopathy was assessed using the Capacity Profile (CAP). Longitudinal development trends were assessed by means of linear regression analysis, while the degree of discontinuity of the development trajectories was quantified using the Mean Absolute Deviation from Perfect Linear Development (MADPLD). Spearman's rank correlation coefficient and the Mann-Whitney test have been used to investigate the statistical significance of the relationships among the various parameters.

RESULTS

We found that patients with severe non-progressive encephalopathy showed, on average, a linear maturation of 1.5-2.5months per year, irrespective of the neurodevelopmental area considered. Nevertheless, we also discovered that the development trajectories could be discontinuous. Indeed, a given child can show no development sign at all for many years and then suddenly encounter a "development jump", especially in the active language and autonomy areas. However, the long-term development linearity hypothesis seemed to hold true in our study. We also found evidences suggesting that faster development in a given domain could be linked to faster development in other domains, that higher discontinuity in a given area could be associated with higher discontinuity in other areas and that higher degrees of discontinuity could be related to lower developmental evolutions.

CONCLUSIONS

The main findings of this study are important for physicians to form prognoses, counsel effectively and appropriately target therapeutic interventions. In this perspective, there is a strong need to collect long-term repeated follow-up data concerning this group of infants in order to reinforce the findings presented. In fact, these results should be considered as a starting point for further research because they are based on a limited number of patients and more data are needed to confirm the findings.

Weathering the storm: hurricanes and birth outcomes

A growing literature suggests that stressful events in pregnancy can have negative effects on birth outcomes. Some of the estimates in this literature may be affected by small samples, omitted variables, endogenous mobility in response to disasters, and errors in the measurement of gestation, as well as by a mechanical correlation between longer gestation and the probability of having been exposed. We use millions of individual birth records to examine the effects of exposure to hurricanes during pregnancy, and the sensitivity of the estimates to these econometric problems. We find that exposure to a hurricane during pregnancy increases the probability of abnormal conditions of the newborn such as being on a ventilator more than 30min and meconium aspiration syndrome (MAS). Although we are able to reproduce previous estimates of effects on birth weight and gestation, our results suggest that measured effects of stressful events on these outcomes are sensitive to specification and it is preferable to use more sensitive indicators of newborn health.

Respiratory support in meconium aspiration syndrome: a practical guide

Meconium aspiration syndrome (MAS) is a complex respiratory disease of the term and near-term neonate. Inhalation of meconium causes airway obstruction, atelectasis, epithelial injury, surfactant inhibition, and pulmonary hypertension, the chief clinical manifestations of which are hypoxaemia and poor lung compliance. Supplemental oxygen is the mainstay of therapy for MAS, with around one-third of infants requiring intubation and mechanical ventilation. For those ventilated, high ventilator pressures, as well as a relatively long inspiratory time and slow ventilator rate, may be necessary to achieve adequate oxygenation. High-frequency ventilation may offer a benefit in infants with refractory hypoxaemia and/or gas trapping. Inhaled nitric oxide is effective in those with pulmonary hypertension, and other adjunctive therapies, including surfactant administration and lung lavage, should be considered in selected cases. With judicious use of available modes of ventilation and adjunctive therapies, infants with even the most severe MAS can usually be supported through the disease, with an acceptably low risk of short- and long-term morbidities.

Outcome of ventilated infants born at term without major congenital abnormalities

The longer-term outcome of term-born infants without congenital anomalies requiring ventilation in the first 24 h after birth has rarely been reported. Our aims were to determine the mortality and long-term morbidity of such infants and identify risk factors for adverse outcome. The outcomes of 43 of 45 infants born at term consecutively requiring mechanical ventilation were reviewed. The infants had: meconium aspiration syndrome (n = 11), hypoxic ischaemic encephalopathy (HIE) (n = 11), respiratory depression (n = 12), sepsis (n = 5), persistent pulmonary hypertension of the newborn (n = 3) and middle cerebral artery infarction (n = 1). Eleven infants developed seizures (26%), 13 (30%) had abnormal electroencephalograms and 11 (26%) had abnormal MRI scans; 26% had an adverse outcome: six died, and five had severe neurodisability at 2 years. The infants with congenital toxoplasmosis and a middle cerebral artery infarction were excluded from the prediction analysis. In the remaining 41 patients, requirement for anticonvulsants (relative risk, RR = 4.44, 95% CI = 1.48 to 12.70; p = 0.014) and prolonged ventilation (longer than 3 days) (RR 4.83, 95% CI 1.51 to 15.64) predicted adverse outcome. Infants with HIE had an increased risk of adverse outcome (relative risk 5.45, 95% CI 1.01 to 33.85), but an adverse outcome occurred in infants with other diagnoses.

CONCLUSION

Mortality and neurodisability at follow-up were common in infants born at term without major congenital anomalies who required mechanical ventilation in the first 24 h after birth, particularly in those who developed seizures requiring treatment and prolonged ventilation.

Meconium aspiration syndrome (MAS) - Where do we go? Research perspectives

The pathogenetic cascade of meconium aspiration syndrome (MAS) in newborn infants is complex and still incompletely studied. The variable clinical presentation of MAS is basically connected with variation of the amount and consistency of aspirated meconium and also its distribution within the affected lungs. The contributing role of other factors, like intrauterine fetal compromises, lung maturity at the time of insult as well as direct and indirect effects of meconium and its components on the lung alveolar and vascular integrity and development, remains to be studied in further detail. Better understanding of the lung injury processes in MAS, specifically inflammatory injury and non-inflammatory apoptosis and their interplay, may offer new possibilities to treat the severely affected infants, and needs therefore to be explored. Systemic dispersion of intrapulmonary meconium and its components may further induce inflammatory circulatory changes and injurious effects in distant organs, but the mechanisms and clinical significance of these systemic complications are still poorly known. It is thus evident that lung injury processes and potent long-term consequences in various extrapulmonary organs, specifically the brain, as well as development of new approaches to their treatment and prevention form great challenges for future research of MAS.