Cortisol and 17-alpha-hydroxy-progesterone levels in infants with refractory hypotension born at 30 weeks of gestation or less

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.

Hyperdehydroepiandrosterone in neonates with hypoxic ischemic encephalopathy and circulatory collapse

BACKGROUND

Circulatory collapse is a very common complication of the critical illnesses in neonates including neonates with hypoxic ischemic encephalopathy; it can be the end result and cause of death of several conditions. Often, despite treatment with fluid resuscitation and vasopressor agents, circulatory collapse persist, and blood pressure can remain critically low, compromising adequate blood flow to vital organs and brain. Low blood pressure has been associated with increased mortality.

METHOD

To investigate adrenal function in newborn infants who suffer from circulatory collapse during hypoxic ischemic encephalopathy. A total of 30 infants were analyzed in the study: 15 neonates in group A (neonates had hypoxic ischemic encephalopathy with vasopressor resistant hypotension) and 15 neonates in group B (neonates with hypoxic ischemic encephalopathy without vasopressor resistant hypotension). All the studied patients were subjected to history, examinations and laboratory investigation including serum cortisol concentrations and cortisol precursor's levels.

RESULTS

The cortisol concentrations did not differ significantly between the two groups: (12.9 ± 4.3) μg/dL and (12.1 ± 2.4) μg/dL in group A and group B, respectively. There are highly significant differences between groups A and B regarding Dehydroepiandrosterone (342.1 ± 101.3) μg/dL, (33.4 ± 16.5) μg/dL, respectively.

CONCLUSION

In this study, we noticed that cortisol concentrations did not differ between both groups in contrast to the expectation that neonates with critical illnesses should have higher cortisol concentrations than normal neonates. However, the marked increase in dehydroepiandrosterone DHEA may cause decrease cortisol function, so those neonates having accumulation of dehydroepiandrosterone may suffer from manifestation of adrenal insufficiency and vasopressor resistant hypotension in spite of normal cortisol level.

Cortisol precursors in neonates with vasopressor-resistant hypotension in relationship to demographic characteristics

OBJECTIVE

To correlate between cortisol precursors in neonates with vasopressor resistant hypotension and demographic characteristics.

METHODS

We investigated 48 neonates with vasopressor-resistant hypotension. Gestation at birth ranged from 34 to 42 weeks and postnatal age from 4 to 14 days. Cortisol and precursor steroids were measured soon after the onset of volume expansion and inotropes for treatment of shock. Their concentrations were determined using liquid chromatography/mass spectrometry.

RESULTS

In neonates with vasopressor-resistant hypotension, the serum levels of cortisol were within normal nonstress range. There was a strong negative linear association between postnatal age and dehydroepiandrosterone level (r = -0.50, p < .01), which decreased with neonatal age. In addition, there was a significant positive association between gestational age at birth and 17-hydroxy-pregnenolone (r = 0.33, p = .02). No further significant associations were evident between the neonatal weight, duration of gestation or gender and of the levels of cortisol or the other steroids (p > .05). The cause of therapy-resistant hypotension did not appear to influence the steroid levels.

CONCLUSIONS

Cortisol stress response is absent in these severely ill late preterm and term infants. This may be due to inhibition of the distal pathway of cortisol synthesis.

Population pharmacokinetics of unbound hydrocortisone in critically ill neonates and infants with vasopressor-resistant hypotension

OBJECTIVES

To determine the population pharmacokinetics of unbound hydrocortisone in critically ill neonates and infants receiving IV hydrocortisone for treatment of vasopressor-resistant hypotension and to identify patient-specific sources of pharmacokinetic variability.

DESIGN

Prospective observational cohort study.

SETTING

Level 3 neonatal ICU.

PATIENTS

Sixty-two critically ill neonates and infants receiving IV hydrocortisone as part of standard of care for the treatment of vasopressor-resistant hypotension: median gestational age 28 weeks (range, 23-41), median weight 1.2 kg (range, 0.5-4.4), and 29 females.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

Unbound baseline cortisol and postdose hydrocortisone concentrations measured from blood samples being drawn for routine laboratory tests. A one-compartment model best described the data. Allometric weight and postmenstrual age were significant covariates on unbound hydrocortisone clearance and volume of distribution. Final population estimates for clearance, volume of distribution, and baseline cortisol concentration were 20.2 L/hr, 244 L, and 1.37 ng/mL, respectively. Using the median weight and postmenstrual age of our subjects (i.e., 1.2 kg and 28 wk) in the final model, the typical unbound hydrocortisone clearance and volume of distribution were 1.0 L/hr and 4.2 L, respectively. The typical half-life for unbound hydrocortisone was 2.9 hours. A sharp and continuous increase in unbound hydrocortisone clearance was observed at 35 weeks postmenstrual age.

CONCLUSIONS

We report the first pharmacokinetic data for unbound hydrocortisone, the pharmacologically active moiety, in critically ill neonates and infants with vasopressor-resistant hypotension. Unbound hydrocortisone clearance increased with body weight and was faster in children with an older postmenstrual age. Unbound hydrocortisone clearance increased sharply at 35 weeks postmenstrual age and continued to mature thereafter. This study lays the groundwork for evaluating unbound hydrocortisone exposure-response relationships and drawing definitive conclusions about the dosing of IV hydrocortisone in critically ill neonates and infants with vasopressor-resistant hypotension.

Variations in CRHR1 are associated with persistent pulmonary hypertension of the newborn

INTRODUCTION

Persistent pulmonary hypertension of the newborn (PPHN) is associated with substantial infant morbidity and mortality. Recently, genetic associations have been found in idiopathic pulmonary arterial hypertension.

RESULTS

PPHN was significantly (P < 0.05) associated with genetic variants in corticotropin-releasing hormone (CRH) receptor 1, CRHR1 and CRH-binding protein, CRHBP. Association with CRHR1 rs4458044 passed the Bonferroni threshold for significance. No mutations were found in the bone morphogenetic protein receptor type II (BMPR2) gene.

DISCUSSION

We describe previously unreported genetic associations between PPHN and CRHR1 and CRHBP. These findings may have implications for further understanding the pathophysiology of PPHN and treatment.

METHODS

We performed a family-based candidate gene study to examine a genetic association with PPHN and sequenced the BMPR2 gene in 72 individuals. We enrolled 110 families with infants diagnosed with PPHN based on inclusion criteria. After medical chart review, 22 subjects were excluded based on predefined criteria, and DNA samples from 88 affected infants and at least one parent per infant were collected and genotyped. Thirty-two single-nucleotide polymorphisms in 12 genes involved in vasoconstriction/vasodilation, lung development, surfactant regulation, or vascular endothelial cell function were investigated using family-based association tests.

Transient adrenal insufficiency in the premature newborn

PURPOSE OF REVIEW

Relative adrenal insufficiency is a controversial phenomenon described in adults and children with critical illness, especially septic shock. In the past 2 decades, relative adrenal insufficiency has also been reported in the critically ill premature as well as term newborn. The present study will review the initial and more recent studies addressing adrenal insufficiency in the premature infant.

RECENT FINDINGS

Studies suggest that 'relative adrenal insufficiency' is a contributing factor to hemodynamic instability in the sick preterm newborn. Many ill preterm newborns have inappropriately low serum cortisol concentrations and respond to steroid administration. Adrenal insufficiency is transient and likely reflects normal adrenal physiology at younger gestational ages. There is no general consensus on its diagnosis, effective minimum dose for treatment and duration of treatment.

SUMMARY

More large scale, multicenter, randomized, double-blind studies are needed to make the diagnosis of relative adrenal insufficiency and to determine the indication, dose, complications and outcome of glucocorticoid therapy.