Reference ranges and factors affecting the human corticotropin-releasing hormone test in preterm, very low birth weight infants

Association between ambient air pollution a week prior to delivery and preterm birth using a nationwide study in Sweden

BACKGROUND

Air pollution exposure has been linked with increased risk of preterm birth, which is one of the leading causes of infant mortality. Limited studies have attempted to explore these associations in low-polluted areas. In this study, we aimed to assess the association between short-term exposure to ambient air pollution and preterm birth in Sweden.

METHOD

In this population-based study we included preterm births between 2014 and 2019 from the Swedish Pregnancy Register. We applied a spatiotemporal model to estimate daily levels of particulate matter <2.5 μm (PM2.5), PM < 10 μm (PM10), nitrogen dioxide (NO2), and ozone (O3) at the residential address of each participant. We applied a time-stratified case-crossover design with conditional logistic regression analysis to estimate odds ratios (OR) of preterm birth per 10 μg/m3 (PM10, NO2, O3) and 5 μg/m3 (PM2.5) increase in air pollution exposure at 0-6-day lag. Two-pollutant models were applied to evaluate the independent association of each exposure on preterm birth. We also stratified by maternal characteristics to identify potential effect modifiers.

RESULTS

28,216 (4.5%) preterm births were included. An increase in O3 exposure was associated with increased odds of preterm birth [OR = 1.06 per 10 μg/m3 (95% CI, 1.02; 1.10]. PM2.5 and PM10 were not significantly associated with preterm birth, and NO2 displayed a negative nonlinear association with preterm birth. We did not observe any notable effect modification, but we found suggestive larger associations between O3 and preterm birth when stratifying by male sex, spontaneous delivery, and spring season.

CONCLUSIONS

Increased O3 exposure one week before delivery was associated with an increased risk of preterm birth in Sweden, a country with levels of air pollution below the current World Health Organization air quality guidelines. Increases in O3 levels with climate change make these findings especially concerning.

A Preliminary Study of Correlates of Premature Birth and Their Influence on Cortisol Levels in Young Children

OBJECTIVE

The HPA-axis is programmed during early infancy, but a lot is unknown about the programming of the HPA-axis in prematurely born or small for gestational age (SGA) children. Therefore, the aim of this preliminary study was to investigate the influence of prematurity and variables associated with birth on cortisol levels in young children.

METHODS

Cortisol was measured in a cross-sectional design in 38 premature born participants (<37 weeks of gestation), aged between 3 - 9 years old. Correlates of prematurity (degree of prematurity and birth delivery route) were investigated in relationship with cortisol levels with regression analysis.

RESULTS

Corrected for sex, delivery by C-section was associated with lower cortisol levels in the children (ß = -.42, p = .028), with an explained variance of 34%.

CONCLUSION

Birth delivery route by C-section is associated with lowered (or flattened) cortisol levels in children born prematurely. This is clinically relevant and might have important implications, because an HPA-axis disturbance might lead to developmental problems later on in life. However, future research is necessary to investigate the underlying indications for performing a C-section, which will help to understand factors that influence the HPA-axis development in children born prematurely.

The changes in adrenal developmental programming and homeostasis in offspring induced by glucocorticoids exposure during pregnancy

Clinically, synthetic glucocorticoids are often used to treat maternal and fetal related diseases, such as preterm birth and autoimmune diseases. Although its clinical efficacy is positive, it will expose the fetus to exogenous glucocorticoids. Adverse environments during pregnancy (e.g., exogenous glucocorticoids exposure, malnutrition, infection, hypoxia, and stress) can lead to fetal overexposure to endogenous maternal glucocorticoids. Basal glucocorticoids levels in utero are crucial in determining fetal tissue maturation and its postnatal fate. As the synthesis and secretion organ of glucocorticoids, the adrenal development is crucial for the growth and development of the body. Studies have found that glucocorticoids exposure during pregnancy could cause abnormal fetal adrenal development, which could last after birth or even adulthood. As the key organ of fetal-originated adult disease, the adrenal developmental programming has a profound impact on the health of offspring, which can lead to many chronic diseases in adulthood. However, the aberrant adrenal development in offspring caused by glucocorticoids exposure during pregnancy and its intrauterine programming mechanism have not been systematically clarified. Therefore, this review summarizes recent research progress on the short and long-term hazards of aberrant adrenal development induced by glucocorticoids exposure during pregnancy, which is of great significance for the analysis of aberrant adrenal development and clarify the intrauterine origin mechanism of fetal-originated adult disease.

Salivary Cortisol Levels and Clinical Signs of Stress in Premature Neonates Treated with Vimala Massage: A Randomized Controlled Trial

Background: In neonatal intensive care units across the world, premature neonates are exposed to a very stressful environment with high levels of noise, bright lights, pain, infections, invasive procedures, and a lack of maternal contact. Stress is manifested by increased cortisol levels and clinical signs of stress. Objective: To assess the impact of Vimala massage on (1) salivary cortisol levels (primary outcome) and (2) clinical signs of stress (secondary outcomes) in premature neonates. Methods: Neonates (28-36 weeks gestational age) admitted to a nursery unit were randomized one-to-one to receive 15-20 min of Vimala massage administered by their parents twice daily and usual care, or to usual care alone. Salivary cortisol levels were measured by enzyme-linked immunosorbent assay (ELISA) on days 1 and 5. Heart rate, respiratory rate, caloric intake, weight gain, and growth were recorded daily. Groups were compared with t tests, U-tests, and repeated measures analysis of variance. Results: Seventy neonates, 35 in each group, were included. Groups were comparable at baseline. The median decrease in salivary cortisol levels was 0.12 μg/dL in the massage group and 0.07 μg/dL in the control group (p = 0.22). Over 5 days, the massage group had significant decreases in resting heart rate (p = 0.003) and respiratory rate (p = 0.028), and greater weight gains (p = 0.0002), relative to controls. Conclusions: In this randomized trial, adding Vimala massage to usual nursery care was not associated with a significant decrease in salivary cortisol levels in premature neonates, when compared with usual nursery care alone. There were improvements in clinical signs of stress.

Rescue doses of antenatal corticosteroids, children's neurodevelopment, and salivary cortisol after a threatened preterm labor: a 30-month follow-up study

BACKGROUND

Antenatal corticosteroids reduce neonatal complications when administered to women at risk for preterm birth. Moreover, antenatal corticosteroid rescue doses are recommended for women who remain at risk after the initial course. However, there is controversy about the most appropriate frequency and the exact timing of administering additional antenatal corticosteroid doses because there are potential long-term negative effects on infants' neurodevelopment and physiological stress functioning.

OBJECTIVE

This study aimed to (1) to assess the long-term neurodevelopmental effects of receiving antenatal corticosteroid rescue doses in comparison with receiving only the initial course; (2) to measure the cortisol levels of infants of mothers who received antenatal corticosteroid rescue doses; (3) to examine a potential dose-response effect of the number of antenatal corticosteroid rescue doses on children's neurodevelopment and salivary cortisol.

STUDY DESIGN

This study followed 110 mother-infant pairs who underwent a spontaneous episode of threatened preterm labor until the children were 30 months old, regardless of their gestational age at birth. Among the participants, 61 received only the initial course of corticosteroids (no rescue dose group), and 49 participants required at least one rescue dose of corticosteroids (rescue doses group). The follow-up was carried out at 3 different times, namely at threatened preterm labor diagnosis (T1), when the children were 6 months of age (T2), and when the children were 30 months of corrected age for prematurity (T3). Neurodevelopment was assessed using the Ages & Stages Questionnaires, Third Edition. Saliva samples were collected for cortisol level determination.

RESULTS

First, the rescue doses group showed lower problem-solving skills at 30 months of age than the no rescue doses group. Second, the rescue doses group demonstrated higher salivary cortisol levels at 30 months of age. Third, a dose-response effect was found that indicated that the more rescue doses the rescue doses group received, the lower the problem-solving skills and the higher the salivary cortisol levels at 30 months of age.

CONCLUSION

Our findings reinforce the hypothesis that additional antenatal corticosteroid doses provided after the initial course may have long-term effects on the neurodevelopment and glucocorticoid metabolism of the offspring. In this regard, the results raise concerns about the negative effects of repeated doses of antenatal corticosteroids in addition to a full course. Further studies are necessary to confirm this hypothesis to help physicians reassess the standard antenatal corticosteroid treatment regimens.

Postnatal corticosteroid response in neonates < 32 weeks and relation with placental pathology

Acute chorioamnionitis and maternal vascular malperfusion are associated with an increased risk of bronchopulmonary dysplasia. To prevent bronchopulmonary dysplasia, postnatal corticosteroids are given to preterm neonates. Clinical observations indicate not all neonates respond to corticosteroids, the so-called non-responders. This study aimed to investigate the association between placental pathology and short-term response to postnatal corticosteroids in neonates < 32 weeks postconceptional age at risk for bronchopulmonary dysplasia. All neonates < 32 weeks born between 2009 and 2016, receiving corticosteroids in the course of BPD, were included. The preterm neonates were divided into three groups depending on placental histology: acute chorioamnionitis, maternal vascular malperfusion, or no placental pathology. Respiratory support was assessed prior to treatment and at days 4 and 7. A responder was defined as extubation within 7 days after starting corticosteroid treatment. In total, 52% of the chorioamnionitis neonates, 67% of the maternal vascular malperfusion neonates, and 58% of neonates in the no pathology group were responders. The odds ratio for extubation was 0.53 (0.18-1.55) at day 4 and 0.66 (0.23-1.97) at day 7, in the chorioamnionitis group compared to the maternal vascular malperfusion.

CONCLUSION

Short-term response to postnatal corticosteroids did not significantly differ between premature neonates born after acute chorioamnionitis, maternal vascular malperfusion, or no placenta pathology. However, a trend of better corticosteroid response in maternal vascular malperfusion neonates was found, potentially due to differences in prenatal pulmonary development and postnatal cortisol.

WHAT IS KNOWN

• Bronchopulmonary dysplasia is related to chorioamnionitis and maternal vascular malperfusion. • Corticosteroids remain an important treatment in the course of bronchopulmonary dysplasia despite conflicting results and non-responsiveness in some preterm neonates.

WHAT IS NEW

• Non-responsiveness might be related to differences in pulmonary inflammation and systemic cortisol due to predispositions triggered by chorioamnionitis or maternal vascular malperfusion. • Neonates born after maternal vascular malperfusion seem to respond better to postnatal corticosteroid treatment.

Hair cortisol and dehydroepiandrosterone sulfate concentrations in healthy beef calves from birth to 6 months of age

Cortisol (C) and dehydroepiandrosterone (DHEA) are recognized as the main fetal steroids, and they are likely to influence fetal development and have long-term effects on newborn hypothalamic-pituitary-adrenal axis (HPA) function. DHEA is often measured as its sulfates and expressed as DHEA-S. Hair analysis represents a promising methodological approach for the non-invasive measurement of steroids, allowing for a retrospective analysis of the total exposure to steroids over time, and avoiding the influence of acute events or circadian fluctuations. Hair cortisol and DHEA concentrations have been investigated in cows, but no studies have been performed on calves. The object of this study was to evaluate hair cortisol (HC) and hair DHEA-S (HDHEA-S) concentrations in beef calves from birth to six months of age. Hair samples of 12 beef calves (seven males, five females) were firstly collected at birth (T1) and then every three weeks up to six months of age (T2-T10), collecting only the re-grown hair. HC and HDHEA-S were analyzed by radioimmunoassay (RIA). Calves sex, weight and APGAR score were registered immediately after birth. Statistical analysis revealed that both HC and HDHEA-S were influenced by sampling time (P < 0.001). HC concentrations were higher at T1 compared to all subsequent samplings (T2-T10, P < 0.01); HC concentrations were higher at T2 compared to T4-T10 (P < 0.01), while no further changes were detected from T3 onward. Higher HDHEA-S concentrations were registered at T1, T2 and T3 compared to all the other samplings (P < 0.01). No correlation was found between hair concentrations of both steroids and calf sex or birthweight. APGAR score was negatively correlated only with HC at birth (P < 0.05). These data demonstrate that C and DHEA-S are quantifiable in the hair of calves and are influenced by their age. The higher HC detected at birth (T1) probably reflects the high serum C concentrations present late in pregnancy and increased by the fetal HPA axis, by which parturition is initiated in cows. The highest HDHEA-S at birth (T1) in calves indicates that the largest amounts of DHEA and its sulfates are produced during fetal development. Moreover, the findings of higher HC at three weeks after birth and of higher HDHEA-S until six weeks after birth, suggest that C and DHEA secretion continues also beyond birth, and that these steroids could be involved in the events occurring during the challenging first weeks of age in the calf.

Antenatal Glucocorticoids Reduce the Incidence of Refractory Hypotension in Low Birthweight Infants during the Early Neonatal Period, but Do Not Affect It beyond This Time

OBJECTIVE

This study aimed to clarify the effect of antenatal glucocorticoids (AGs) on the incidence of refractory hypotension (RH) in very low birthweight (VLBW) infants after the first week of life.

STUDY DESIGN

We included VLBW infants born at a gestational age of <30 weeks and divided them into three groups: the complete group (born within 7 days of completing a single course [two doses] of AGs), the incomplete group (born without complete course), and the late delivery group (born at ≥8 days after a single course). We compared the incidence and period of onset of RH among the three groups.

RESULTS

A total of 115 infants were enrolled. The incidence of RH in the first week of life was significantly lower in the complete group than in the other groups. However, there was no significant difference in the incidence of RH after the first week of life among the groups.

CONCLUSION

AGs contribute to circulatory stabilization during the first week of life, but this effect does not last after 1 or 2 weeks of administration. In infants who receive AGs, physicians should consider that the risk of RH after the first week of life is not low.

Association between Baseline Cortisol Serum Concentrations and the Effect of Prophylactic Hydrocortisone in Extremely Preterm Infants

OBJECTIVE

To define nomograms of serum cortisol values before 24 hours of postnatal life for extremely preterm infants and determine whether baseline cortisol values affect the benefit/risk ratio of prophylactic hydrocortisone to improve survival without bronchopulmonary dysplasia (BPD).

STUDY DESIGN

We performed a predefined secondary analysis of the multicenter randomized controlled PREMILOC trial that included inborn infants delivered before 28 weeks of gestation. Nomograms of baseline serum cortisol values measured in 325 enrolled patients were determined for male and female neonates and correlated to perinatal events. BPD-free survival and severe adverse events were analyzed in placebo and hydrocortisone groups according to the cortisol z score in multivariate logistic regression models.

RESULTS

Increased cortisol levels measured before 24 hours following birth were associated with a significantly higher chance of BPD-free survival only in placebo-treated infants (aOR [95% CI] 1.57 [1.08-2.27], P = .02) based on sex-specific nomograms for baseline cortisol levels. The cortisol z score for infants treated with prophylactic hydrocortisone predicted a risk of high-grade intraventricular hemorrhage (aOR [95% CI] 1.82 [1.06-3.15], P = .03) and spontaneous intestinal perforation (aOR [95% CI] 4.81 [1.34-17.22], P = .02).

CONCLUSIONS

We found no predictive value of baseline cortisol levels for BPD-free survival in infants born extremely preterm treated with hydrocortisone. However, high cortisol levels early after birth were associated with a greater risk of severe intraventricular hemorrhage and spontaneous intestinal perforation in infants treated with hydrocortisone and, therefore, a lower benefit/risk ratio for the treatment.

TRIAL REGISTRATION

EudraCT 2007-002041-20, ClinicalTrial.gov: NCT00623740.

Antenatal Risk Factors Associated with Spontaneous Intestinal Perforation in Preterm Infants Receiving Postnatal Indomethacin

OBJECTIVE

To determine if antenatal variables affect the risk of spontaneous intestinal perforation (SIP) among preterm infants when prophylactic indomethacin is used.

STUDY DESIGN

Retrospective case-control study of infants <29 weeks of gestational age between January 2010 and June 2018 at one hospital. SIP was defined as acute abdominal distension and pneumoperitoneum without signs of necrotizing enterocolitis at <14 days of life. Each case (n = 57) was matched with 2 controls (n = 114) for gestational age and birth year. Maternal and infant data were abstracted until the SIP or equivalent day for controls. Univariate analyses were followed by adjusted conditional logistic regressions and reported as OR and 95% CI.

RESULTS

Mothers of cases were younger, more often delivering multiples (31% vs 14%, P = .007), and less abruptions (15% vs 29%, P = .045) but did not differ in intra-partum betamethasone, magnesium, or indomethacin use. Prophylactic indomethacin was given on day 1 to 99% of infants. SIP was associated with a shorter interval from last betamethasone dose to delivery (46 hours vs 96 hours, P = .01). Dopamine use (14% vs 4%, P = .02), volume expansion (23% vs 8%, P = .003), and high grade intraventricular hemorrhage (28% vs 8%, P = .0008) were related postnatal factors. The adjusted odds of SIP increased by 1% for each hour decrease between the last dose of betamethasone and delivery (OR 1.01, 95% CI 1.002-1.019) and with multiple births (OR 2.66, 95% CI 1.05-6.77).

CONCLUSIONS

Antenatal betamethasone given shortly before delivery is associated with an increased risk of SIP. Potential interaction with medications such as postnatal indomethacin needs study.

Corticosteroids for Neonatal Hypotension

Several limitations and controversies surround the definition of hypotension; however, it remains one of the most common problems faced by neonates. Approximately 15% to 30% of neonates with hypotension fail to respond to volume and/or vasopressor or inotropes. They are considered to have refractory hypotension. Although it is thought to have multiple causes, absolute and relative adrenal insufficiency is considered as the main reason for refractory hypotension. This article focuses on the role of adrenal insufficiency in causing refractory hypotension in preterm and term infants, the different options of corticosteroids available, and their risk/benefit profiles.

No Association of Antenatal Synthetic Glucocorticoid Exposure and Hair Steroid Levels in Children and Adolescents

CONTEXT

Antenatal synthetic glucocorticoid (sGC) treatment constitutes a potent programming factor of the hypothalamic-pituitary-adrenal (HPA) axis. Previous findings from our group revealed long-term changes in cortisol stress reactivity following antenatal sGC therapy. However, the few prior studies exclusively relied on spot measurements of phasic HPA axis activity, which may not adequately capture cortisol output over prolonged periods of time.

OBJECTIVE

To address this gap, the current study utilized hair steroid concentrations, a valid marker of integrated long-term HPA-axis activity, to investigate endocrine changes in individuals treated with antenatal sGC.

DESIGN, SETTING, AND PARTICIPANTS

This cross-sectional study comprised 76 term-born children (7-12 years) and 58 adolescents (14-18 years). Cumulated hormonal secretion in scalp hair over a 3-month period was determined for different biomarkers of tonic HPA axis activity by liquid chromatography coupled with tandem mass spectrometry. Hair steroid levels were compared between participants with antenatal sGC therapy (dexamethasone or betamethasone) and different control groups.

RESULTS

Findings from this study provide no evidence for a significant effect of antenatal sGCs on long-term hair steroid concentrations. Participants treated with antenatal sGC exhibited comparable levels of hair cortisol, cortisone, dehydroepiandrosterone, and cortisol/dehydroepiandrosterone ratios compared to those of mothers who had been admitted to hospital for pregnancy complications but had never received sGC therapy and controls from physiological pregnancies.

CONCLUSION

In conjunction with data from previous studies, it is thus tempting to speculate that sGC may affect the capacity of dynamic changes and flexible adaption of an individual's HPA axis rather than changes in tonic steroid output.

Prenatal Glucocorticoid Treatment Completeness and Steroid Hormonal Levels as Related to Infant and Maternal Health

This study was conducted to confirm the negative associations between testosterone and cortisol levels and health and developmental outcomes in very low-birth weight (VLBW) infants after controlling for prenatal glucocorticoid (GC) treatment. Seventy-four VLBW infant-mother pairs were recruited from a neonatal intensive care unit in the Southeastern United States. We divided the pairs into the complete (n = 58) and incomplete (n = 16) GC treatment groups. Data on infants and mothers were obtained at birth, 40 weeks' postmenstrual age, and 3 and 6 months' corrected age. Salivary testosterone and cortisol levels of the pairs were determined at 40 weeks' postmenstrual age using enzyme immunoassay. Log-linear and general linear mixed models showed that gestational age and birth weight were lower when testosterone was 1 pg/mL higher. When cortisol was 1 μg/dL higher, technology dependence at discharge was higher and motor development at 6 months was lower. Mothers with complete GC treatment had greater parity and gravida, more prenatal visits, and more medical complications. The study outcomes supported our hypothesis that steroid hormonal levels are more predictive of infant health and development than GC treatment completeness. Single dose of GC treatment might be just as effective as 2 doses, although further study with more subjects would be needed to confirm. As the associations with steroid hormonal levels lasted longer than the GC treatment associations, we recommend confirming the predictive effects of testosterone and cortisol levels after 6 months.

Late-onset glucocorticoid-responsive circulatory collapse in premature infants

Late-onset glucocorticoid-responsive circulatory collapse (LGCC) in infants is characterized by sudden onset of hypotension and/or oliguria, which is resistant to volume expanders and inotropes but responds rapidly to intravenous glucocorticoids. LGCC occurs after the first week of life mainly in relatively stable very low birth weight (VLBW) infants. In Japan, the incidence of LGCC is reported to be 8%. Relative adrenal insufficiency (AI) is considered the most likely cause of LGCC, but its detailed pathophysiology remains unclear. Intrinsic and extrinsic factors may affect the pathophysiological mechanism. LGCC should be recognized as one of the high-risk complications in VLBW infants and managed promptly and properly, because if it is not, it may cause life-long neurological problems. To diagnose relative AI, an accurate evaluation of adrenal function is necessary; however, the interpretation of basal serum cortisol levels is difficult in preterm infants after 7 days of life. To recognize LGCC, it is recommended that blood pressure and urine volume be carefully monitored, even outside of the transitional period. If no underlying causes are documented or volume expansion and inotropic support fail, intravenous hydrocortisone should be initiated, and an additional dose of hydrocortisone is required when the response is inadequate. There are few reports to verify or characterize LGCC and this phenomenon has not been recognized worldwide to date. This review summarizes the current knowledge about LGCC in premature infants and evaluates the most significant new findings regarding its pathophysiology, treatment, and prognosis.

Basal serum cortisol concentration in very low birth weight infants

BACKGROUND

The aim of our study was to measure the basal serum cortisol concentration immediately after birth and to determine its association with perinatal factors and clinical outcomes in very low birth weight (VLBW) infants.

METHODS

Basal serum cortisol level was obtained within one hour after birth in inborn VLBW infants. The association between the basal serum cortisol level and perinatal and clinical outcomes was analyzed by comparing the groups with high versus low cortisol levels.

RESULTS

In total, 80 infants were included. The median concentration of basal serum cortisol was 167 nmol/L with an interquartile range of 98-298 nmol/L. The basal serum cortisol concentration positively correlated with elapsed time from the last betamethasone dose. Low serum cortisol concentration was associated with antenatal corticosteroid therapy, low lactic acid level, and low leukocyte count at birth. Basal serum cortisol level was not associated with mortality and neonatal morbidities including hypotension and severe grade intraventricular hemorrhage.

CONCLUSION

Both maternal corticosteroid therapy and perinatal distress may affect the basal serum cortisol concentration in VLBW infants early after birth.

Adrenal function links to early postnatal growth and blood pressure at age 6 in children born extremely preterm

BACKGROUND

Low birth weight in term-born individuals correlates with adverse cardiometabolic outcomes; excess glucocorticoid exposure has been linked to these relationships. We hypothesized that cortisol and adrenal androgens would correlate inversely with birthweight and directly with markers of cardiometabolic risk in school-aged children born extremely preterm; further, preterm-born would have increased cortisol and adrenal androgens compared to term-born children.

METHODS

Saliva samples were obtained at age 6 from 219 preterm-born children followed since birth and 40 term-born children and analyzed for dehydroepiandrosterone (DHEA) and cortisol. Cortisol was also measured at home (awakening, 30' later, evening).

RESULTS

For preterm-born children, cortisol and DHEA correlated inversely with weight and length Z-scores at 36 weeks PMA and positively with systolic BP. DHEA was higher in preterm-born than term-born children (boys p < 0.01; girls p = 0.04). Cortisol was similar between preterm-born and term-born at study visit; however, preterm-born children showed a blunted morning cortisol. In term-born children, DHEA correlated with BMI (p = 0.04), subscapular, and abdominal skinfold thicknesses (both p < 0.01).

CONCLUSION

Cortisol and DHEA correlated inversely with early postnatal growth and directly with systolic BP in extremely preterm-born children, suggesting perinatal programming. Blunted morning cortisol may reflect NICU stress, as seen after other adverse childhood experiences (ACEs).

Plasma cortisol and ACTH levels in 416 VLBW preterm infants during the first month of life: distribution in the AGA/SGA population

OBJECTIVE

The aim of this study is to establish the serum level distribution of cortisol and ACTH in VLBW preterm newborns and determine which neonates are ideal candidates for the stimulation test for adrenal insufficiency.

METHODS

Plasma cortisol and ACTH levels were evaluated in 416 VLBW newborns on days 1, 7, and 30 of life. Gender, gestational age, weight, type of delivery, RDS prophylaxis, and perinatal morbidities were considered as potential variability factors.

RESULTS

Cortisol and ACTH levels significantly decreased between 1, 7, and 30 days. Significantly higher cortisol levels were found at lower gestational ages and in infants born by vaginal delivery, whereas lower levels were observed in those born after maternal corticosteroid treatment. The distribution of cortisol and ACTH levels in healthy infants born by cesarian section is presented.

CONCLUSION

Even if high or low levels were not frequently linked to illness, the presented distribution data may indicate that the newborns are ideal candidates for the stimulation test.

Clinical utility of stimulation tests in infants with suspected adrenal insufficiency (AI)

Diagnosis of adrenal insufficiency (AI) in infants can be difficult. While a low random cortisol can signal AI, often confirmatory tests are required when clinical suspicion is strong but the cortisol levels are equivocal. Several studies have demonstrated that in sick preterm infants, there is relative adrenal insufficiency (RAI) defined as an inadequate cortisol production relative to the degree of stress or illness, a condition which can last for several weeks, while in term infants the adrenal axis is mature at birth (Bagnoli F, Mori A, Fommei C, Coriolani G, Badii S, et al. ACTH and cortisol cord plasma concentrations in preterm and term infants. J Perinatol 2013;33:520-4). Adrenocorticotrophic hormone (ACTH) and corticotrophin releasing hormone (CRH) stimulation tests have been validated in infants in several studies. In light of recent reports of false-negative results of stimulation tests, it is imperative to highlight the pitfalls of these tests. The purpose of this communication is to bring attention to the accuracy of timing of these tests in infants.

Novel method of measuring chronic stress for preterm infants: Skin cortisol

BACKGROUND AND OBJECTIVES

Infants who begin life in the medicalized environment of the neonatal intensive care unit (NICU) do so under stressful conditions. Environmental exposures are often abrasive to vulnerable infants, while invasive and noninvasive lifesaving interventions provide additional pain and/or stress. The most commonly selected biomarker to measure stress is cortisol. The skin is the barrier between the external environment and communicates with our neurological, endocrine and immune regulatory networks. To examine if skin cortisol may be a reliable biomarker of stress, NICU stress exposure and repeated measurements of skin cortisol in very preterm infants were examined retrospectively during the first 6 weeks of life. The temporal relationship between skin cortisol and NICU stress exposure was also analyzed.

MATERIALS AND METHODS

Participants included 82 preterm infants born weighing less than 1500 g, admitted to a level III NICU, with a mean gestational age of 28.5 weeks. Infants were studied from birth through 6 weeks of life. NICU stress data was collected using the Neonatal Infant Stressor Scale. Skin samples were collected using d-squame tape as soon after birth as possible and every two weeks thereafter.

RESULTS

On average, infants experienced approximately 43 stressful events per day during the first 6 weeks of life in the NICU. Stress level and cortisol reactivity varied by gestation age. Higher stress resulted in higher cortisol for infant >28 weeks; lower stress scores were associated with higher stress for infants <28 weeks. Stress exposure during 7 days prior to cortisol sampling yielded the highest AUC for the 2 groups. A statistically significant interaction was identified between gestational age and stress exposure during the previous 7 days (p < 0.01).

CONCLUSION

This is the first study to demonstrate skin cortisol as a preterm infant biomarker of chronic stress exposure. For infants with appropriate skin maturation, this non-invasive sampling method provides several benefits. Importantly, this method may be less intrusive and disruptive for preterm infants.

Persistent Effects of Antenatal Synthetic Glucocorticoids on Endocrine Stress Reactivity From Childhood to Adolescence

CONTEXT

Antenatal synthetic glucocorticoid (sGC) therapy has been identified as a potent programming factor of the hypothalamic-pituitary-adrenal (HPA) axis. We previously observed significantly increased cortisol stress responses in 6- to 11-year-old, term-born children exposed to antenatal sGCs compared with controls. These findings call for longitudinal follow-up studies to evaluate long-term effects of antenatal sGCs, given that adolescence is marked by a substantial shift of HPA axis functioning.

OBJECTIVE

This study aimed to longitudinally investigate the stability of antenatal sGC-related effects on cortisol stress reactivity from childhood to adolescence.

DESIGN, SETTING, AND PARTICIPANTS

To evaluate long-term trajectories of antenatal sGCs, we longitudinally followed a subsample (n = 44) of our children's cohort into adolescence (14 to 18 years old) for a second assessment. To this end, 22 adolescents with antenatal sGC exposure and 22 untreated controls underwent a standardized laboratory stressor [Trier Social Stress Test (TSST)].

RESULTS

Besides a general increase in HPA axis reactivity from childhood to adolescence (P < 0.05), participants treated with antenatal sGCs showed significantly higher cortisol levels in response to the TSST compared with controls during both developmental stages (P < 0.05). Furthermore, we observed a moderating effect of sGCs on rank-order stability of cortisol stress reactivity from childhood to adolescence (P < 0.05) with a trend (P = 0.07) for higher rank-order stability in sGC-exposed individuals (r = 0.37) compared with controls (r = -0.20).

CONCLUSION

These findings suggest that antenatal sGCs yield long-term changes of HPA axis reactivity that persist into adolescence and may confer increased vulnerability for developing stress-related disorders.

Retrospective review of Synacthen testing in infants

BACKGROUND

A subnormal cortisol response (30 min level (C^30min)<550 nmol/L) to synthetic adrenocorticotrophic hormone/Synacthen test (SDST) in all infants does not necessarily indicate underlying or persistent hypothalamic-pituitary-adrenal axis pathology.

METHODS

We retrospectively evaluated the diagnoses and outcomes in 68 infants who had a SDST at age <6 months from 2011 to 2014.

RESULTS

29 (43%) infants had a subnormal SDST. Causative pathology was identified in 9/29 (31%). In 20/29 (69%) with no identified pathology, repeat SDST was normal in 18/20 (90%) at median age 0.6 (range 0.1-3.2) years but persistently subnormal in 2. Those with a transient abnormality were more likely to be small for gestational age (P=0.03) and had higher initial SDST C^30min (390 nmol/L vs 181 nmol/L, P=0.01) than those with pathology.

CONCLUSION

Specific aetiology can be identified in a third of infants with a subnormal SDST. When the aetiology remains elusive, adrenal function should be reassessed as the problem can be transient.

Neonatal factors related to center variation in the incidence of late-onset circulatory collapse in extremely preterm infants

BACKGROUND

Although late-onset circulatory collapse (LCC) is widely recognized in Japan, its etiology and the reason for center variation in its incidence remain unclear. This study's objectives were to identify the perinatal and neonatal factors related to LCC and to estimate the factors related to the center variation in the incidence of LCC.

METHODS

Extremely preterm infants born between 2008 and 2012 who were registered in the database of the Neonatal Research Network, Japan were retrospectively analyzed. LCC was defined as a clinical diagnosis of LCC and the administration of steroids. We first identified the factors that were significantly related to LCC. We then examined the cause of the center variation in the incidence of LCC, using the standardized incidence ratios (SIRs) of LCC and individual factors.

RESULTS

The factors significantly associated with LCC included low gestational age (odds ratio [OR]: 1.13), small for date (OR: 1.43), male sex (OR: 1.26), antenatal steroid use (OR: 1.19), respiratory distress syndrome (OR: 1.25), chronic lung disease at 36 weeks (OR: 1.16), periventricular leukomalacia (PVL) (OR: 2.57), necrotizing enterocolitis (OR: 0.59), retinopathy of prematurity (ROP) (OR: 1.73), high-frequency oscillating ventilation (HFOV) use (OR: 1.31), parenteral nutrition (OR: 1.38), and red blood cell (RBC) transfusion (OR: 1.94). The SIR of LCC ranged from 0.05 to 2.94, and was positively correlated with SIRs of PVL, ROP, HFOV use and RBC transfusion.

CONCLUSION

PVL, ROP, HFOV use and RBC transfusion were found to be correlated with the center variation in the incidence of LCC.

Association between plasma cortisol and death or vasopressor refractory hypotension in preterm neonates: a prospective, cohort study

OBJECTIVES

Temporal relation between adrenal insufficiency and hypotension is poorly understood. We examined the association between basal and post-stimulation cortisol and death or vasopressor refractory hypotension in preterm neonates.

STUDY DESIGN

Prospective cohort study in ≤30 weeks' and/or <1,250 g weight. Primary outcome-composite of death or vasopressor refractory hypotension by day 14 of life. Plasma cortisol levels were measured at 24-36 h (T1), 72-84 h (T2) and 10 days (T3), and post-stimulation cortisol at T1 and later at T2 and T3 if the adrenal response was inadequate earlier.

RESULTS

Basal cortisol (µg/dl) at 24-36 h was significantly higher in the outcome group (37.2 ± 21.1 vs. 22.04 ± 14.6; mean difference (MD) (95% confidence interval (CI)): -15.1 (-23.6, -6.6); p = 0.005). High basal cortisol at 24-36 h (odds ratio (OR) (95% CI): 1.044 (1.009, 1.079); p = 0.01) and need for ventilation (OR (95% CI): 9.7 (1.2, 81.2); p = 0.04) independently increased the risk of death or vasopressor refractory hypotension.

CONCLUSION

Preterm neonates who died or developed vasopressor refractory hypotension by day 14 had significantly elevated basal cortisol at 24-36 h of life.

Terlipressin-induced modifications of Doppler ultrasound signals of systemic arteries in preterm infants with vasoactive-resistant patent ductus arteriosus: A pilot study

PURPOSE

To study the effects of terlipressin (TP) infusion on systemic perfusion, estimated with pulsed-wave Doppler ultrasonography of systemic arteries, in a population of extremely low birth-weight (ELBW) preterm infants with vasoactive-resistant ductus arteriosus.

METHODS

This prospective, observational cohort included, during five years, 12 ELBW infants with hemodynamically significant patent ductus arteriosus and absent or reversed diastolic flow at Doppler ultrasonography of systemic arteries, despite treatment and high-dose vasoactive support. We measured flow velocity of the anterior cerebral, right renal, and superior mesenteric arteries before and after TP infusion. Changes were evaluated by Spearman's rho coefficient analysis, Wilcoxon signed-rank, and Friedman test.

RESULTS

Time-averaged mean velocity of the renal artery (P = .028) increased, while renal pulsatility (P = .010) and resistance (P = .004) indexes, and cerebral artery resistance index (P = .021) decreased after TP infusion. Time-averaged mean velocity of the anterior cerebral artery proportionately increased with dopamine dose (rho = 0.678; P = .015), but showed opposite shifts after TP (rho = -0.662; P = .024).

CONCLUSIONS

These changes suggest that TP may improve systemic perfusion in the ELBW infants with vasoactive-resistant ductus arteriosus.

Corticotrophin-releasing hormone stimulation tests for the infants with relative adrenal insufficiency

BACKGROUND

Very low birthweight (VLBW) infants are considered to be vulnerable to relative adrenal insufficiency (RAI); however, diagnosis is difficult in some clinical settings. Considering this background, it is necessary to establish a diagnosis of RAI in preterm infants.

OBJECTIVE

In this study, we attempted to clarify the difference in response to CRH stimulation tests for preterm infants with or without RAI.

METHODS

Between June 2009 and December 2015, we performed CRH stimulation tests for preterm infants born at a gestational age of <30 weeks at around 2 weeks of age. Retrospectively, subjects were classified into two groups: infants with RAI (n = 9) or without RAI (n = 17) based on the clinical symptoms and responsiveness to hydrocortisone.

RESULTS

We found no difference in base or peak serum cortisol levels related to CRH stimulation tests between the two groups; however, delta cortisol levels and responsive ratio (peak-to-base ratio) were significantly reduced in infants with RAI. 140 nmol/L for delta cortisol or 1.5 times for peak-to-base ratio may be cut-off levels in preterm infants.

CONCLUSION

This study provides evidence that base cortisol levels of preterm infants with RAI were not different from those without RAI; however, CRH stimulation tests may be a useful tool for the diagnosis of RAI in preterm infants.

Steroid use for refractory hypotension in congenital diaphragmatic hernia

PURPOSE

Guidelines for diagnosis and treatment of adrenal insufficiency (AI) in newborns with congenital diaphragmatic hernia (CDH) are poorly defined.

METHODS

From 2002 to 2016, 155 infants were treated for CDH at our institution. Patients with shock refractory to vasopressors (clinically diagnosed AI) were treated with hydrocortisone (HC). When available, random cortisol levels <10 μg/dL were considered low. Outcomes were compared between groups.

RESULTS

Hydrocortisone was used to treat AI in 34% (53/155) of patients. That subset of patients was demonstrably sicker, and mortality was expectedly higher for those treated with HC (37.7 vs. 17.6%, p = 0.0098). Of the subset of patients with random cortisol levels measured before initiation of HC, 67.7% (21/31) had low cortisol levels. No significant differences were seen in survival between the high and low groups, but mortality trended higher in patients with high cortisol levels that received HC. After multivariate analysis, duration of HC stress dose administration was associated with increased risk of mortality (OR 1.11, 95% CI 1.02-1.2, p = 0.021), and total duration of HC treatment was associated with increased risk of sepsis (OR 1.04, 95% CI 1.005-1.075, p = 0.026).

CONCLUSION

AI is prevalent amongst patients with CDH, but prolonged treatment with HC may increase risk of mortality and sepsis.

Associations of Maternal Testosterone and Cortisol Levels With Health Outcomes of Mothers and Their Very-Low-Birthweight Infants

OBJECTIVE

Although the roles of testosterone and cortisol in various health problems have been extensively investigated, little is known about their associations with health outcomes in mothers and their very-low-birthweight (VLBW) infants when maternal testosterone and cortisol are examined together during the postpartum period.

METHOD

The 101 mother-VLBW infant pairs were recruited from the neonatal intensive care unit of a tertiary medical center in the southeastern United States. Demographic information, pregnancy and labor complications of mothers, and health and growth outcomes of infants were obtained from medical records and interviews with mothers. Maternal salivary testosterone and cortisol levels were determined using enzyme immunoassay.

RESULTS

Linear regression showed that mothers who were older and had a larger body mass index experienced more pregnancy complications, whereas mothers who were single and had a cesarean section experienced more labor complications. Generalized linear models showed that mothers with high cortisol levels had more antepartum hemorrhage, whereas infants of mothers with high cortisol levels had fewer neurological insults and shorter hospitalizations than other infants. More mothers experienced premature prolonged rupture of membranes (PPROM) than chorioamnionitis, and maternal medical complications were negatively associated with infant health outcomes except PPROM, which was positively associated with infant outcomes.

CONCLUSIONS

High maternal cortisol levels were associated with maternal health problems during pregnancy. Beneficial effects of PPROM and high maternal cortisol levels on infant health outcomes were important findings, and understanding the mechanisms of these relationships may be of practical value for clinicians and researchers.

Glucocorticoid Programming in Very Preterm Birth

Very preterm (i.e., <32 weeks of gestation) infants admitted to the neonatal intensive care unit are compromised in their abilities to respond adequately to common threats like hemodynamic changes and reduced energy supplies, which is partly attributable to adrenocortical insufficiency. Conversely, later in life, these infants show features of increased glucocorticoid bioactivity, such as abdominal fat distribution, raised blood pressure, insulin resistance and diabetes mellitus type 2. It has been suggested that the very preterm newborn responds to the adverse postnatal environment with a sustained elevation in hypothalamus-pituitary-adrenal axis activity that persists beyond infancy. This has implications for subsequent growth, body composition, metabolism, neurodevelopment and, ultimately, long-term disease risk. The mechanisms underpinning these associations are not fully elucidated yet. This review gives a brief summary of studies that investigated adrenocortical function in very preterm newborns and how the axis changes with age, as a possible explanation for the association between prematurity and long-term outcome.

Late-onset circulatory collapse of prematurity

Late-onset circulatory collapse (LCC) is a refractory hypotension occurring after the early neonatal period (>day 7), in very low-birthweight infants. Typically, infants stabilized within the early neonatal period develop sudden onset of circulatory collapse after the early neonatal period. The underlying pathophysiology of LCC is considered to be relative adrenal insufficiency, which is well known in Japan, but is not widely accepted in North America or Europe. The current increase in LCC in Japan suggests that the principal trigger is related to recent trends in neonatal medicine and/or newly introduced treatments for preterm infants, but the pathophysiology has not been fully elucidated. In this review, based on current knowledge regarding LCC, the pathophysiology is discussed.

Maternal use of prednisolone is unlikely to be associated with neonatal adrenal suppression-a single-center study of 16 cases

The use of supra-physiological, exogenous corticosteroids in pregnancy may lead to neonatal adrenal suppression. We report on a single-center, case series study carried out between 2006 and 2014, which included all newborns (n = 16) of mothers using prednisolone ≥10 mg/day during pregnancy. Newborns were routinely assessed according to hospital protocol, with follow-up until 6 weeks after birth. We investigated the clinical symptoms and biochemical findings of adrenal suppression occurring in the newborns. Mean dose of maternal prednisolone was 29.7 ± 16.1 mg/day with a mean duration of 18.4 ± 15.4 weeks. Five newborns showed hypoglycemia with normal serum cortisol concentrations and urinary steroid profiles. Two newborns had abnormal urinary steroid profiles, probably the result of prematurity, but with adequate adrenal stress response during clinical sepsis.

CONCLUSION

In this retrospective case series, we found no evidence of prolonged effects of maternal prednisolone use during pregnancy on the neonatal hypothalamic-pituitary-adrenal axis. What is known: • The use of prednisolone during pregnancy may cause increased steroid levels in the fetus by partially passing through the placenta. • So far, there was very limited data available on the occurrence of adrenal suppression in the newborn of mothers using prednisolone during pregnancy. What is new: • The use of high-dosage prednisolone during pregnancy for ≥1 week (mean duration of 18.4 ± 15.4 weeks), prior to delivery, appears to have little influence on the neonatal hypothalamic-pituitary-adrenal axis.

Adrenocortical insufficiency and refractory hypotension in preterm infants

Preterm, very low birthweight (VLBW) infants are prone to life-threatening hypotension secondary to hypothalamic-pituitary-adrenal axis immaturity, resulting in adrenocortical insufficiency. Clinical presentations of inotrope-resistant refractory hypotension are usually evident, but interpretation of serum cortisol may pose much difficulty to front-line neonatologists. This review examines the salient pathophysiology of adrenocortical insufficiency in the immediate postnatal period, characterises its endocrinological abnormalities, and describes the typical and variant clinical presentations. Based on existing evidence, a practical scheme is proposed for logical interpretation of circulating cortisol levels and management of inotrope-resistant refractory hypotension in VLBW infants.

Paradoxical diurnal cortisol changes in neonates suggesting preservation of foetal adrenal rhythms

Studies suggested the presence of foetal adrenal rhythms of cortisol, which are entrained in antiphase to maternal rhythms. In contrast, neonates are thought to have no adrenal rhythm until 2-3 months after birth. To test the hypothesis that a foetal-type adrenal rhythm is preserved after birth, saliva samples were collected from 65 preterm/term infants during hospital stay (30-40 weeks corrected age) at 10:00 and 19:00 h. Cortisol levels were assessed for their diurnal difference and dependence on antenatal/postnatal clinical variables. Cortisol levels were lower during periods 15-28 days and >28 days than ≤5 days of life. Lower cortisol was associated with pregnancy-induced hypertension (PIH), gestational age <28 weeks, and mechanical ventilation after birth. Higher cortisol was associated with vaginal delivery and non-invasive ventilation support at saliva collection. PIH and non-invasive mechanical ventilation at saliva collection were associated with cortisol levels even after adjustment for postnatal age. Cortisol levels were higher in the evening than in the morning, which was unassociated with gestational and postnatal age. Higher cortisol levels in the evening suggest the preservation of a foetal-type diurnal rhythm. Cortisol levels are associated with intrinsic and extrinsic variables, such as PIH, delivery mode, gestational age, and respiratory conditions.

Interaction of steroid receptor coactivators and estrogen receptors in the human placenta

Female sex steroid hormones such as estrogen and progesterone have a pivotal role in maintaining pregnancy in human and animals. Especially, estrogen exerts specific effects on the cardiovascular system and angiogenesis, and thus affects significantly on placentation. Although the functions of estrogen have been emphasized during pregnancy, their signaling pathways in the placenta have not been fully understood. In this study, estrogen signaling was evaluated according to gestational age. Human placenta samples were collected and divided into early preterm (n=10), late preterm (n=18), and term (n=20) groups. First, serum estrogen concentration and corticotropin-releasing hormone (CRH) mRNA expression, which is known as gestation clock gene, were increased following gestation age in our experimental condition, as we expected. Next, the expression of estrogen receptors (ERs) and steroid receptor coactivators (SRCs) in the placenta was evaluated. ERα (ESR1) and ERβ (ESR2) were expressed highly at term period compared with early preterm. In addition, SRC family including SRC1, SRC2, and SRC3 was expressed in the human placenta, and the levels of SRC1, SRC2, and SRC3 were increased in the placenta at the late stage of gestation. The interaction of ERs with SRCs was also examined, which was significantly enhanced at term period. In the immunostaining results, it was indicated that ERs and SRCs were all dominantly expressed in syncytiotrophoblast cells. These results suggested that SRC1, SRC2, and SRC3 were expressed and interact with ERs highly at the late stage of gestation, and may amplify the signaling of estrogen in the placenta to maintain pregnancy.

Neonatal hydrocortisone therapy does not have a serious suppressive effect on the later function of the hypothalamus-pituitary-adrenal axis

AIM

This study investigated whether providing extremely low birthweight (ELBW) infants with a large amount of hydrocortisone had a serious suppressive effect on the later function of the hypothalamus-pituitary-adrenal (HPA) axis.

METHODS

We evaluated the function of the HPA axis in 58 ELBW infants receiving 9.0 ± 7.2 mg/kg of intravenous and 68.1 ± 34.1 mg/kg of oral hydrocortisone using a human corticotropin-releasing hormone stimulation test. The mean age at investigation was 12.0 ± 5.2 months. The response was judged to be normal when the maximum to minimum ratio of the plasma adrenocorticotropic hormone (ACTH) concentration was >2, the peak value of the serum cortisol concentration was >552 nmol/L, or the increment was >193 nmol/L than baseline concentration.

RESULTS

Of the 58 infants studied, 51 (88%) displayed a normal response to both the ACTH and cortisol secretion and seven infants (12%) who were judged to be poor responders exhibited a peak cortisol value of >386 nmol/L without any episode of adrenal insufficiency.

CONCLUSION

Providing ELBW infants with a daily low dose of long-term hydrocortisone therapy should not lead to a serious suppressive effect on the later function of the HPA axis, regardless of the administration method.

Critical illness-related corticosteroid insufficiency in children

Adequate adrenocortical function is essential for survival in critical illness. Most critically ill patients display elevated plasma cortisol concentrations, which reflects activation of the hypothalamic-pituitary-adrenal axis and is considered to be a homeostatic adaptation. However, many critically ill patients have 'relative' or 'functional' adrenal insufficiency, which is characterized by an inadequate production of cortisol in relation to an increased demand during periods of severe stress. Recently, the term 'critical illness-related corticosteroid insufficiency' (CIRCI) was coined. CIRCI occurs as a result of a decrease in adrenal steroid production or tissue resistance to glucocorticoids. An international task force of the American College of Critical Care Medicine issued recommendations for the diagnosis and management of this condition in adult patients. We review the prevalence, diagnosis, and therapeutic approach to adrenal insufficiency in critically ill children. We found a lack of consensus within the pediatric field as to the optimal approach to CIRCI, and call for an international task force to establish unified guidelines.

Hypotension following patent ductus arteriosus ligation: the role of adrenal hormones

OBJECTIVE

To test the hypothesis that an impaired adrenal response to stress might play a role in the hypotension that follows patent ductus arteriosus (PDA) ligation.

STUDY DESIGN

We performed a multicenter study of infants born at <32 weeks' gestation who were about to undergo PDA ligation. Serum adrenal steroids were measured 3 times: before and after a cosyntropin (1.0 μg/kg) stimulation test (performed before the ligation), and at 10-12 hours after the ligation. A standardized approach for diagnosis and treatment of postoperative hypotension was followed at each site. A modified inotrope score (1 × dopamine [μg/kg/min] + 1 × dobutamine) was used to monitor the catecholamine support an infant received. Infants were considered to have catecholamine-resistant hypotension if their greatest inotrope score was >15.

RESULTS

Of 95 infants enrolled, 43 (45%) developed hypotension and 14 (15%) developed catecholamine-resistant hypotension. Low postoperative cortisol levels were not associated with the overall incidence of hypotension after ligation. However, low cortisol levels were associated with the refractoriness of the hypotension to catecholamine treatment. In a multivariate analysis: the OR for developing catecholamine-resistant hypotension was OR 36.6, 95% CI 2.8-476, P = .006. Low cortisol levels (in infants with catecholamine-resistant hypotension) were not attributable to adrenal immaturity or impairment; their cortisol precursor concentrations were either low or unchanged, and their response to cosyntropin was similar to infants without catecholamine-resistant hypotension.

CONCLUSION

Infants with low cortisol concentrations after PDA ligation are likely to develop postoperative catecholamine-resistant hypotension. We speculate that decreased adrenal stimulation, rather than an impaired adrenal response to stimulation, may account for the decreased production.

Sedation and analgesia to facilitate mechanical ventilation

Regardless of age, health care professionals have a professional and ethical obligation to provide safe and effective analgesia to patients undergoing painful procedures. Historically, newborns, particularly premature and sick infants, have been undertreated for pain. Intubation of the trachea and mechanical ventilation are ubiquitous painful procedures in the neonatal intensive care unit that are poorly assessed and treated. The authors review the use of sedation and analgesia to facilitate endotracheal tube placement and mechanical ventilation. Controversies regarding possible adverse neurodevelopmental outcomes after sedative and anesthetic exposure and in the failure to treat pain is also discussed.

ACTH and cortisol cord plasma concentrations in preterm and term infants

OBJECTIVE

To measure the adrenocorticotropic hormone (ACTH) and cortisol (F) cord plasma levels in preterm and term infants in relation to their mode of delivery.

STUDY DESIGN

We studied 180 newborns appropriate for gestational age (GA) with birth weights between 365 and 4380 g and GAs between 21 and 41 weeks divided into three groups: born by vaginal delivery (VD), elective cesarean section (ECS) and emergency cesarean section (EMCS). ACTH and F levels were valued with enzyme-linked immunosorbent assay testing. Median concentrations were compared between groups by Student's T-test for independent and paired data. Multiple regression analysis was used to investigate the effect of GA on F and ACTH concentrations.

RESULT

A significant positive correlation between GA and plasma concentrations of ACTH (P<0.05) was found in the whole population, but not between GA and F (P=NS). A significant positive correlation was found between GA and plasma concentrations of both ACTH (P=0.01) and F (P=0.03) in VD. In those born by ECS, we demonstrated a positive correlation not only between plasma concentrations of ACTH (P=0.0000) and F (P=0.00002), respectively, with GA, but also a correlation between ACTH and F (P=0.0004). No significant correlations were found in the EMCS group (P=NS).

CONCLUSION

Our results suggest simultaneous pituitary-adrenal maturation, which is complete only at term. The responsiveness of preterm babies to different stressful stimulations is similar to the terms' but quantitatively lower, and the secretion of ACTH and F may not suffice in severe pathological circumstances.

Limited response to CRH stimulation tests at 2 weeks of age in preterm infants born at less than 30 weeks of gestational age

BACKGROUND

The high incidence of glucocorticoid-responsive complications in extremely preterm infants suggests the immaturity of their adrenal function; however, knowledge of the hypothalamus-pituitary-adrenal (HPA) axis in extremely preterm infants is limited.

METHODS

To clarify the characteristics of the HPA axis in preterm very low birthweight (VLBW) infants, we performed CRH tests repeatedly: at about 2 weeks of age and at term (37-41 weeks of postmenstrual age) for 21 VLBW infants with a gestational age (GA) <30 weeks at birth.

RESULTS

Basal cortisol values at 2 weeks of age were significantly higher than those at term in VLBW infants < 30 weeks of gestation at birth (304·1 ± 146·3 nmol/l vs 184·7 ± 108·2 nmol/l). Response to corticotropin-releasing hormone (CRH) stimulation tests at 2 weeks of age was significantly lower than at term (delta cortisol 148·3 ± 90·7 nmol/l vs 271·8 ± 167·0 nmol/l, delta ACTH 3·9 ± 3·2 pmol/l vs 12·3 ± 9·2 pmol/l, respectively). We found that earlier GA contributed to the higher basal cortisol values, and antenatal glucocorticoid (AG) contributed to the lower response of cortisol to CRH tests at 2 weeks of age.

CONCLUSIONS

VLBW infants showed a characteristic pattern in the HPA axis at 2 weeks of age: higher basal cortisol values and lower response to CRH tests. This study suggested that AG was related to the lower response to CRH tests, at least partly.

Adrenal function in preterm infants undergoing patent ductus arteriosus ligation

BACKGROUND

Targeted milrinone treatment for low left ventricular output (LVO) reduces the incidence of acute cardiorespiratory instability following ligation of patent ductus arteriosus (PDA) in preterm infants. Despite this, some infants continue to experience postoperative deterioration. Adrenal insufficiency related to prematurity has been postulated as a possible mechanism.

OBJECTIVES

To describe adrenal function in premature infants undergoing PDA ligation and to investigate its association with pre- and postoperative clinical and echocardiography-derived indices of disease severity.

METHODS

A retrospective cohort study was conducted over a 2-year period on infants who underwent PDA ligation and had preoperative adrenocorticotropic hormone (ACTH) stimulation. All infants were screened by echocardiography for low LVO at 1 h after surgery and treated with intravenous milrinone if LVO <200 ml/kg/min. The primary outcome evaluated was low LVO at 1 h after surgery. Secondary outcomes included hypotension and oxygenation and ventilation failure occurring within 24 h.

RESULTS

A total of 35 infants at a median gestation of 25.4 (24.5-26.4) weeks and weight at birth of 700 (600-810) g were included. Baseline median cortisol measured preoperatively was 202 (137-403) nmol/l. Following the ACTH stimulation test, 3 infants had cortisol ≤500 nmol/l while 15 had ≤750 nmol/l. There was no association seen between any cortisol value and low LVO postoperatively. Post-ACTH cortisol ≤750 nmol/l was significantly associated with hypotension (p = 0.03) and oxygenation (p = 0.04) and ventilation (p = 0.008) failure. Receiver-operator characteristic curve showed a high predictive value of post-ACTH cortisol for all clinical outcomes.

CONCLUSIONS

Post-ACTH cortisol (≤750 nmol/l) may be associated with clinical indices of postoperative cardiorespiratory instability. Relative adrenal insufficiency may play a role in the etiology of post-PDA ligation hemodynamic and respiratory instability.

The effect of massage on heart rate variability in preterm infants

OBJECTIVE

To test the hypothesis that massage would improve autonomic nervous system (ANS) function as measured by heart rate variability (HRV) in preterm infants.

STUDY DESIGN

Medically stable, 29- to 32-week preterm infants (17 massage, 20 control) were enrolled in a masked, randomized longitudinal study. Licensed massage therapists provided the massage or control condition twice a day for 4 weeks. Weekly HRV, a measure of ANS development and function, was analyzed using SPSS generalized estimating equations.

RESULTS

Infant characteristics were similar between groups. HRV improved in massaged infants but not in the control infants (P<0.05). Massaged males had a greater improvement in HRV than females (P<0.05). HRV in massaged infants was on a trajectory comparable to term-born infants by study completion.

CONCLUSION

Massage-improved HRV in a homogeneous sample of hospitalized, medically stable, preterm male infants and may improve infant response to exogenous stressors. We speculate that massage improves ANS function in these infants.

Sex differences in cardiorespiratory transition and surfactant composition following preterm birth in sheep

Male preterm infants are at greater risk of respiratory morbidity and mortality than females but mechanisms are poorly understood. Our objective was to identify the basis for the “male disadvantage” following preterm birth using an ovine model of preterm birth in which survival of females is greater than males. At 0.85 of term, fetal sheep underwent surgery (11 female, 10 male) for the implantation of vascular catheters to monitor blood gases and arterial pressure. After cesarean delivery at 0.90 of term, lambs were monitored for 4 h while spontaneously breathing; lambs were then euthanized and static lung compliance measured. We analyzed surfactant phospholipid composition in amniotic fluid and in bronchoalveolar lavage fluid (BALF) taken at necropsy; we also analyzed surfactant protein ( SP) expression in lung tissue. Before delivery male fetuses tended to have lower pH ( P = 0.052) compared with females. One hour after delivery, males had significantly lower pH and higher arterial partial pressure of CO2 (PaCO2), lactate, glucose, and mean arterial pressure than females. Two males died 1 h after birth. Static lung compliance was 37% lower in males than females ( P < 0.05). In BALF, males had significantly more protein, a lower percentage of the phosphatidylcholine (PC) 32:0 (dipalmitoylphosphatidylcholine) and higher percentages of PC34:2 and PC36:2. There were no sex-related differences in lung architecture or expression of SP-A, -B, -C, and -D. The lower lung compliance in male preterm lambs compared with females may be due to altered surfactant phospholipid composition and function. These changes may compromise gas exchange and impair respiratory adaptation after male preterm birth.

Adrenocortical function in the postoperative pediatric cardiac surgical patient

PURPOSE OF REVIEW

Corticosteroids are frequently used in the postoperative care of children with congenital heart disease. This review describes the function of the adrenocortical axis in this population and the effects of corticosteroids on cardiovascular function. In addition, it examines the diagnosis of adrenal insufficiency in this population and provides an overview of recent studies on the use of steroids in treating hemodynamic instability in these children.

RECENT FINDINGS

Corticosteroids improve hemodynamic parameters in children with shock following congenital heart surgery. This improvement may be due to treatment of adrenal insufficiency or from direct cardiovascular effects of corticosteroids. The diagnosis of adrenal insufficiency in this population is challenging as low cortisol levels do not consistently correlate with adverse outcomes.

SUMMARY

Because of the lack of evidence delineating what the normal adrenocortical function is in this population, cortisol levels alone are not sufficient to justify treating with steroids in this population. Corticosteroids are beneficial in improving hemodynamics in children with shock after congenital heart surgery, but the adverse effects of the therapy in this context are not fully known. Prospective trials are necessary to clarify which patients may benefit from steroid therapy and to examine long-term effects of steroids.

The use of an early ACTH test to identify hypoadrenalism-related hypotension in low birth weight infants

OBJECTIVE

To investigate if in preterm newborns, an early adrenocorticotropin hormone (ACTH) test can identify possible transient adrenal insufficiency (TAI), using significant hypotension as a clinical marker.

STUDY DESIGN

We studied 40 premature newborns born 24 to 29 weeks gestational age (GA) before 8 h of life. Serum cortisol levels were obtained before and 40 min after administration of 1.0 mcg kg(-1) cosyntropin. Inotropes were used to treat hypotension based on clinical assessment following no response to fluid boluses. Functional echocardiogram was used to support the clinical diagnosis of hypotension. The accuracy of the ACTH test was evaluated using receiver operating characteristic (ROC) curve.

RESULT

Study patients had mean GA of 26.6 weeks and birth weight of 876 g. In all, 30% required inotropes. The area under the ROC curve for the ACTH test was 87%. Using a cutoff of an increase in cortisol below 12% from baseline had 75% sensitivity and 93% specificity for detecting hypotension. This cutoff was associated with bronchopulmonary dysplasia (8/12 vs 7/28, 95% CI: 0.1 to 0.72), but not with other morbidities or death.

CONCLUSION

An early ACTH test using the above cutoff has high specificity for detecting hypotension, and thus, can serve as a marker for potential TAI in preterm newborns. Future studies should focus on identifying those newborns for which steroid supplementation would be most beneficial.

Nationwide surveillance of circulatory collapse associated with levothyroxine administration in very-low-birthweight infants in Japan

BACKGROUND

Although the administration of levothyroxine sodium (LT4) to premature infants had been considered safe, several cases of late-onset circulatory collapse (LCC) following the administration of LT4 in very-low-birth-weight (VLBW) infants have been reported in Japan since 2008. This study was performed to investigate the incidence of LCC associated with the administration of LT4 to VLBW infants.

METHODS

A questionnaire regarding LCC with or without an association with LT4 administration in VLBW infants from 2006 to 2008, was sent to 212 hospitals belonging to the Japan Neonatologist Association.

RESULTS

Data of 8727 VLBW infants were analyzed, and 46 cases of LCC associated with the administration of LT4 were reported in this surveillance. Especially, an analysis for infants weighing between 1000 and 1499 g at birth revealed that the incidence of LCC with the administration of LT4 was higher than that of those without LT4.

CONCLUSIONS

LT4 is widely used for infants, including VLBW infants, and no major complications have been reported. However, our study revealed that more than a few cases of LCC were associated with the administration of LT4 in VLBW infants. In conclusion, careful attention is necessary when initiating the administration of LT4 to VLBW infants.

Diagnostic value of salivary cortisol in the CRH stimulation test in premature infants

CONTEXT

According to a recent nationwide survey in Japan, a significant proportion of very low birth weight infants (VLBWI) develop late-onset circulatory collapse after the first week of life. Small doses of glucocorticoid are very effective in these patients, and relative adrenal insufficiency is suspected to be the main cause of the condition. Although the CRH test is required to evaluate the hypothalamic-pituitary-adrenal axis, obtaining multiple blood samples is invasive.

OBJECTIVES

The present study was carried out to validate the consistency of the cortisol profiles of matched serum and saliva samples collected as part of the CRH test from VLBWI.

SUBJECTS/METHODS

In 23 VLBWI with a gestational age of less than 29 wk, we performed CRH tests at 2 wk after birth and at term. Their cortisol values were measured at the baseline and 30 min after the administration of a single dose of human CRH (1 μg/kg) using matched serum and saliva samples.

RESULTS

In 26 CRH tests in 19 infants, we were able to measure both serum and salivary cortisol. Significant correlations were detected between the infants' serum and salivary cortisol values (r=0.78; P<0.0001), the increases in these values induced in response to the CRH test (r=0.81; P<0.0001), and their peak serum and salivary cortisol values (r=0.68; P=0.0001).

CONCLUSION

This study indicated that using salivary cortisol measurements for the CRH test could be a reliable method for evaluating the hypothalamic-pituitary-adrenal axis in VLBWI with gestational age of less than 29 wk.