Persistent pulmonary hypertension of the newborn following elective cesarean delivery at term

Risk factors of transient tachypnea of the newborn developing into pulmonary hypertension of the newborn: a case-control study

Background

Transient tachypnea of the newborn (TTN) is the consequence of delayed resorption of lung fluid. When TTN develops, the infant may develop severe hypoxemia and progress to persistent pulmonary hypertension of the newborn (PPHN).

Objectives

To examine factors associated with the development of PPHN in TTN infants.

Methods

This retrospective study comprised 23 infants in whom a diagnosis of TTN with PPHN (TTN-PPHN) was confirmed and 59 infants with severe TTN without PPHN who required mechanical ventilation between 2009 and 2018 at Songklanagarind Hospital, Thailand. Logistic regression was used to assess factors associated with TTN and PPHN.

Results

The factors identified by univariate analysis that were associated with development of PPHN were oxygen saturation (SpO2) <90% and respiratory rate (RR) ≥70 breaths/min at the time of admission, mean airway pressure (MAP) ≥8 cmH2O, oxygen index (OI) ≥10, partial pressure of oxygen (PaO2) ≤60, partial pressure of carbon dioxide (PCO2) ≥45 mmHg, and infants who did not receive positive pressure ventilation (PPV). In multivariate analyses, RR ≥70 breaths/min (adjusted odds ratio [aOR] 9.96, 95% confidence interval [CI] 2.1-47.29, P < 0.001) and OI ≥10 (aOR 29.22, 95% CI 4.46-191.23, P < 0.001) remained statistically significantly associated with PPHN.

Conclusions

High RR and high OI were factors associated with PPHN in TTN infants.

Can sonographic assessment of pulmonary vascular reactivity following maternal hyperoxygenation predict neonatal pulmonary hypertension? (HOTPOT study protocol)

Background

Persistent pulmonary hypertension of the newborn (PPHN) is a condition that occurs in 0.5–7 per 1000 live births and can result in significant cardiovascular instability in the newborn. It occurs when there is a failure of the normal circulatory transition in the early newborn period. Recent studies have shown that fetal pulmonary vasculature reacts to maternal hyperoxygenation (MH). The aim of the study is to assess if the in-utero response to MH can predict pulmonary hypertension in the early newborn period.

Methods

We will perform a prospective cohort study. It will evaluate the use of fetal echocardiographic Doppler assessment of the pulmonary vasculature prior to and following MH to predict fetuses that may develop pulmonary hypertension in the neonatal period. The study will be undertaken in the Rotunda Hospital, Dublin, Ireland. A fetal ultrasound and echocardiography will be performed on fetuses in the third trimester. Blood flow velocity waveforms will be recorded during periods of fetal quiescence. Pulsatility index (PI), Resistance index (RI), Peak systolic (PSV) and end diastolic velocity (EDV), time-averaged velocity (TAV), acceleration time (AT), and ejection time (ET) will be measured within the fetal distal pulmonary artery (PA). The acceleration-to-ejection time ratio (AT: ET) will be used to assess pulmonary vascular resistance (PVR). Doppler measurements will be taken at baseline and repeated immediately following MH for 10 min (O2 100% v/v inhalational gas) at a rate of 12L/min via a partial non-rebreather mask. Doppler waveform measurements from the umbilical artery (UAD), middle cerebral artery (MCA) ductus arteriosus (DA), aortic isthmus (AoI) and ductus venosus (DV) will also be obtained. After birth, a comprehensive neonatal functional echocardiogram will be performed within the first 24 hours of life.

Discussion

This study proposes to validate methods described to date in investigating the fetal pulmonary vascular response to MH, with expansion of the study subjects to include fetuses at risk of PPHN. Evaluation of the different at-risk subgroups will be informative in relation to the fetal circulatory adaptation close to term. Prediction of neonatal pulmonary hypertension may help guide the pharmacological and neonatal ICU strategies that optimise postnatal survival.

A Study to Assess the Feasibility of Implementing a Web-Based Decision Aid for Birth after Cesarean to Increase Opportunities for Shared Decision Making in Ethnically Diverse Settings

INTRODUCTION

Decision aids are central to shared decision making and are recommended for value-sensitive pregnancy decisions, such as birth after cesarean. However, effective strategies for widespread decision aid implementation, with interactive web-based platforms, are lacking. This study tested the feasibility and acceptability of implementing a Health Insurance Portability and Accountability Act-secure, web-based decision aid to support shared decision making about birth choices after cesarean, within urban, ethnically diverse outpatient settings.

METHODS

A before-and-after design was used to assess feasibility and acceptability for decision aid implementation. Measures included women's knowledge, decisional conflict, birth preferences, birth outcomes, decision aid use, decision aid acceptability ratings (content, features, and functions), and views on how the decision aid supported shared decision making.

RESULTS

Of the 68 women who participated, most were black (46.2%) or Hispanic (35.4%). Their knowledge scores increased by 2.58 points out of 15 (P < .001; d = 0.87), and decisional conflict score reduced by 0.45 points out of 5 points (P < .001; d = 0.69). Forty-four women (65.9%) attempted a vaginal birth after cesarean, of whom 29 (65.7%) succeeded. Women rated decision aid content, features, and functions as good or excellent. Most indicated they would recommend it to others. Health care providers recommended additional strategies to simplify decision aid access and integration into routine care.

DISCUSSION

Implementing web-based decision aids within ethnically diverse practice settings is potentially feasible and worthwhile. However, strategies are needed to improve women's access and to encourage timely decision aid usage to prepare them for decision discussions with health care providers. Sustained implementation will require seamless integration into clinic workflow, which could include health care provider tools (counselling guides) embedded within the electronic health record, along with continuing education to support and engage health care providers in their use.

Factors relating caesarean section to persistent pulmonary hypertension of the newborn

BACKGROUND

Several studies have clearly demonstrated a significantly higher incidence of persistent pulmonary hypertension of the newborn (PPHN) in neonates delivered by caesarean section (CS) compared to those delivered vaginally. The pathophysiological factors underlying the link between CS and PPHN are still poorly understood. In this review, we describe the mechanisms that could explain the association between CS delivery and subsequent PPHN, as well as potential preventive measures.

DATA SOURCES

A literature search was conducted by electronic scanning of databases such as PubMed and Web of Science using the key words "persistent pulmonary hypertension of the newborn", "caesarean section", "iatrogenic prematurity", "oxidative stress", "late preterm", "labor" and "vasoactive agents".

RESULTS

Iatrogenic prematurity, higher rates of late preterm delivery and lack of physiological changes of labor play an important role in the association between CS and PPHN. CS delivery also results in limited endogenous pulmonary vasodilator synthesis and lower levels of protective anti-oxidants in the neonates. In addition, CS delivery exposes infants to a higher risk of respiratory distress syndrome and its concomitant increase in endothelin-1 levels, which might indirectly lead to a higher risk of developing PPHN. We believe that neonates delivered by CS are exposed to a combination of these pathophysiological events, culminating in an endpoint of respiratory distress, hypoxia, acidosis, and delayed transition and thereby increased risks of PPHN. The use of antenatal corticosteroids prior to elective CS in late preterm deliveries, promoting accurate informedconsent process, delaying elective CS to 39 weeks of gestation or beyond and antenatal maternal anti-oxidant supplementation could potentially mitigate the effects of CS delivery and minimize CS-related PPHN.

CONCLUSIONS

The link between CS delivery and PPHN is complex. In view of the rising rates of CS worldwide, there is an urgent need to further explore the mechanisms linking CS to PPHN and experimentally test therapeutic options in order to allow effective targeted interventions.

A rock and a hard place: The selective serotonin reuptake inhibitor dilemmas in addressing perinatal mood and anxiety disorders

Untreated perinatal depression and anxiety increase the risk of pregnancy complications, introducing significant maternal and neonatal complications. Unfortunately, antidepressant treatment with selective serotonin reuptake inhibitors (SSRIs) is similarly associated with adverse perinatal outcomes. Providers should consider all maternal and fetal outcomes when addressing this dilemma.

Fault and blame, insults to the perinatal brain may be remote from time of birth

There is a certainty in malpractice cases that neurodevelopmental deficits are caused by preventable events at birth when the onset, nature, and timing of the insult in the antenatal and natal period are unknown. The biggest problem is determining timing. Electronic fetal monitoring is given excessive importance in legal cases. Before assigning fault on events at birth, a better understanding of developmental neurobiology and limitations of the present clinical biomarkers is warranted. The issues of single versus repeated episodes, timing of antenatal insults, pros and cons of legal arguments, interaction of various etiologic and anatomic factors are discussed.

Prenatal exposure to antidepressants and persistent pulmonary hypertension of the newborn: systematic review and meta-analysis

OBJECTIVE

To examine the risk for persistent pulmonary hypertension of the newborn associated with antenatal exposure to antidepressants.

DESIGN

Systematic review and meta-analysis.

DATA SOURCES

Embase, Medline, PsycINFO, and CINAHL from inception to 30 December 2012.

ELIGIBILITY

English language studies reporting persistent pulmonary hypertension of the newborn associated with exposure to antidepressants. Two independent reviewers extracted data and assessed the quality of each article.

RESULTS

Of the 3077 abstracts reviewed, 738 papers were retrieved and seven included. All seven studies were above our quality threshold. Quantitative analysis was only possible for selective serotonin reuptake inhibitors (SSRIs). Although exposure to SSRIs in early pregnancy was not associated with persistent pulmonary hypertension of the newborn (odds ratio 1.23, 95% confidence interval 0.58 to 2.60; P=0.58), exposure in late pregnancy was (2.50, 1.32 to 4.73; P=0.005). Effects were not significant for any of the moderator variables examined, including study design, congenital malformations, and meconium aspiration. It was not possible to assess for the effect of caesarean section, body mass index, or preterm delivery. The absolute risk difference for development of persistent pulmonary hypertension of the newborn after exposure to SSRIs in late pregnancy was 2.9 to 3.5 per 1000 infants; therefore an estimated 286 to 351 women would need to be treated with an SSRI in late pregnancy to result in an average of one additional case of persistent pulmonary hypertension of the newborn.

CONCLUSIONS

The risk of persistent pulmonary hypertension of the newborn seems to be increased for infants exposed to SSRIs in late pregnancy, independent of the potential moderator variables examined. A significant relation for exposure to SSRIs in early pregnancy was not evident. Although the statistical association was significant, clinically the absolute risk of persistent pulmonary hypertension of the newborn remained low even in the context of late exposure to SSRIs.

Risk factors and mortality among newborns with persistent pulmonary hypertension

Objective: To determine the risk factors for persistent pulmonary hypertension of newborns (PPHN) and their influence on mortality.

Methods: This was an observational study conducted at The Children’s Hospital & the Institute of Child Health, Multan, Pakistan, from July 2011 to June 2012.All admitted babies who had respiratory distress, cyanosis and evidence of hypoxia on ABG,s were diagnosed provided that they were having right- to- left or bidirectional hemodynamic shunting at the ductus arteriosus or at patent foramen ovale along with Tricuspid regurgitation (TR) jet >40 mm of Hg on echocardiography. All the demographic, maternal, antenatal, natal and postnatal data were recorded on a predesigned Performa.

Results: There were 79 patients, including 61 males and 18 females. The most common risk factors observed in our study were male sex (72.1%), cesarean section mode of delivery (54.2%), positive pressure ventilation while resuscitation (44.2%) birth asphyxia (40.4%) and meconium aspiration syndrome (MAS)35.4%. It was found that male sex (88.8%), cesarean-section delivery (77.7%), respiratory distress syndrome (RDS) 44.8% and sepsis (44.4%) were more associated with PPHN in premature infants than with term and post term infants. Out of the total 79 patients, death occurred among 7 preterm and 14 terms and post term infants. As a whole, cesarean section mode of delivery (71.4%), birth asphyxia (57.1%) and female sex (52.4%) were found major risk factors associated with mortality. However, respiratory distress syndrome (Relative Risk RR=5), birth asphyxia (RR=2.5) and male sex (RR=2)were found to be associated with increased risk of mortality in preterm than term and post term infants.

Conclusion: Male gender, cesarean section mode of delivery, MAS and RDS are the major risk factors for PPHN in any age group. RDS, Birth asphyxia and male sex are associated with increased risk of mortality in pre term than term and post term infants.

Pathophysiology, management, and outcome of persistent pulmonary hypertension of the newborn: a clinical review

Persistent Pulmonary Hypertension of the Newborn (PPHN) results from the failure of relaxation of the pulmonary vasculature at birth, leading to shunting of non-oxygenated blood from the pulmonary to the systemic circulation. More often, full term and near-term infants are affected, however it is not uncommon to see PPHN in preterm infants who have respiratory distress syndrome. In some infants pulmonary vascular remodeling is present at birth, pointing toward the prenatal onset of the disease process. Regardless of the etiology, PPHN should be diagnosed and treated as soon as possible to avoid hypoxia related short term and long-term morbidities. The mainstay therapy is the treatment of the underlying condition along with several promising therapeutic modalities such as oxygen supplementation, mechanical ventilation, nitric oxide, phosphodiesterase inhibitors, prostaglandins analogs, endothelin receptor antagonists, and extracorporeal membrane oxygenation. The optimal approach to the management of PPHN remains controversial. After discharge from the NICU, infants with PPHN warrant long-term follow up since they are at risk for neurodevelopmental disabilities and chronic health conditions.

Antenatal betamethasone improves postnatal transition in late preterm lambs with persistent pulmonary hypertension of the newborn

BACKGROUND

Persistent pulmonary hypertension of the newborn (PPHN) is associated with increased oxidative stress in pulmonary arteries (PAs). Betamethasone decreases the oxidative stress and improves antioxidant balance in PPHN. We investigated whether antenatal betamethasone improves pulmonary vasodilation and postnatal oxygenation in late preterm lambs with PPHN.

METHODS

PPHN was induced by constriction of fetal ductus arteriosus from 128 to 136 d gestation. Ewes were given two intramuscular doses of betamethasone or saline at 24 and 12 h before cesarean-section delivery at 136 d gestation, simulating late preterm birth. Newborn lambs were mechanically ventilated for 8 h with monitoring of blood gas and hemodynamic variables. Lungs were harvested postmortem to determine oxidative stress markers and in vitro responses of PAs.

RESULTS

Postnatal arterial partial pressure of oxygen and pH were higher and the oxygenation index and arterial partial pressure of carbon dioxide were lower in betamethasone-treated lambs. PA pressure was lower and systemic pressure higher in lambs treated with betamethasone. Betamethasone decreased the oxidative stress markers and increased endothelial nitric oxide synthase expression in ventilated PPHN lungs.

CONCLUSION

Antenatal betamethasone decreases oxidative stress and improves postnatal transition in late preterm lambs with PPHN. This study suggests a potential benefit for antenatal betamethasone in late preterm births.

A case study of maternal response to the implied antepartum diagnosis of inevitable labor dystocia

Two pregnant women, one obese and one of extremely small stature, received antepartum recommendations from their health care providers to schedule cesarean births. In response, both women sought providers who would support their desire to attempt vaginal birth. The women's perspectives on their birth experiences along with the pertinent medical record data from their pregnancies and births provide a reminder about the inherent normalcy of birth amid the current culture of interventive obstetrical practices.