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.

A review of potential pharmacogenetic effects on catecholamine responses.

Considerably, variability in the clinical response to inotropic agents is observed and could be explained partially by the genetic variants, such as single-nucleotide polymorphism (SNP) in genes encoding for enzymes implicated in catecholamines synthesis, metabolism, storage and release or in the signaling pathway. This review highlights the potential effect of pharmacogenetics studies in hemodynamic response and identified 11 SNPs that could be relevant to explain the high variability drug response for a same dose. Cardiovascular instability, such as hypotension, is one of the premature birth complications. The pharmacogenetics studies evaluating these SNP may be useful to better understand the clinical outcome, particularly in this population.

Hemodynamic correlates of low umbilical cord vitamin D and ionized calcium.

Vitamin D deficiency and hypocalcemia are associated with gestational hypertension. Therefore, we hypothesized that umbilical cord [Ca(2+)] and [vitamin D] are correlated with perinatal blood pressures. Mothers and newborns comprised vitamin D sufficient (vitamin D ≥ 50 nM, range 52-111 nM, n = 14), and vitamin D deficient groups (vitamin D < 50 nM, range 13-49 nM, n = 29). Cord [Ca²âº] was negatively correlated with maternal systolic pressure (SBP) (r = -0.56, p < 0.01) and positively correlated with neonatal SBP (r = +0.55, p < 0.01) in the vitamin D deficient group. We conclude that low umbilical cord [vitamin D] and [Ca²âº] may predispose mothers to higher and newborns to lower blood pressures.

Transient heart block in a neonate associated with previously undiagnosed maternal anti-Ro/SSA and anti-La/SSB antibodies.

This report presents the case of an infant who was born with transient complete heart block. The cardiac rhythm converted to normal sinus rhythm within 12 hours of life. Following the diagnosis in this infant of congenital heart block, both the mother and the infant were tested for autoantibodies. Both were found to be strongly positive for anti-Ro/SSA antibodies. The infant was also weakly positive for the anti-La/SSB antibodies and her mother moderately positive for the same. Congenital heart block associated with these maternal antibodies is well documented in the literature; however, this is the only reported case that documents a transient nature of the complete heart block.

Comparison of three sites to check the pulse and count heart rate in hypotensive infants.

BACKGROUND: Current international guidelines state that heart rate counted at the brachial pulse must be absent or <60 b x min(-1) to diagnose cardiac arrest. Some data suggest that this site may not be the best to check cardiac activity. Hypotension is a likely real scenario of the need for chest compressions in infants. We compared the performance of three sites of pulse palpation (brachial, carotid, and femoral) for detecting and counting heartbeat in hypotensive infants. METHODS: In an operating theater of a pediatric teaching hospital in Italy, we studied 40 anesthetized hypotensive infants just prior to surgery, checked by two doctors and two nurses by a cross-sectional, repeated-measures study design. Each examiner, blind to the monitoring data of the patient, was asked to find the infant's arterial pulse within 10 s and count heart rate for 15 s. During each examination, the order of the three sites was randomized. RESULTS: Among successful detections, femoral pulse palpation resulted as the most successful, rapid, and accurate site to detect and count heart rate in hypotensive infants. CONCLUSIONS: Femoral palpation proved to be the best site for detecting heartbeat and counting heart rate in hypotensive infants. These findings challenge the current guidelines. More data are needed, but the current standard of brachial pulse assessment is debatable.