Pediatric research
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Epigenetics is defined as mitotically and meiotically heritable changes in gene expression that do not involve a change in the DNA sequence. Two major areas of epigenetics-DNA methylation and histone modifications-are known to have profound effects on controlling gene expression. DNA methylation is involved in normal cellular control of expression, and aberrant hypermethylation can lead to silencing of tumor-suppressor genes in carcinogenesis. ⋯ In this review, we will examine the relationship between miRNAs and epigenetics. We examine the effects of miRNAs on epigenetic machinery, and the control of miRNA expression by epigenetic mechanisms. Epigenetics is defined as heritable changes in gene expression that do not involve a change in DNA sequence.
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Despite its use, there is little evidence to support volume infusion (VI) during neonatal cardiopulmonary resuscitation (CPR). This study compares 5% albumin (ALB), normal saline (NS), and no VI (SHAM) on development of pulmonary edema and restoration of mean arterial pressure (MAP) during resuscitation of asphyxiated piglets. Mechanically ventilated swine (n=37, age: 8 +/- 4 d, weight: 2.2 +/- 0.7 kg) were progressively asphyxiated until pH <7.0, Paco2 >100 mm Hg, heart rate (HR) <100 bpm, and MAP <20 mm Hg. ⋯ VI during resuscitation did not improve MAP, and acute recovery of MAP was poorer with NS compared with ALB. VI was associated with increased pulmonary edema. In the absence of hypovolemia, VI during neonatal resuscitation is not beneficial.
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Randomized Controlled Trial Multicenter Study
Left ventricular contractility in extremely premature infants in the first day and response to inotropes.
The aim was to assess myocardial contractility in infants born <30 wk gestation developing low systemic blood flow (SBF) in the first day, and the effect of dobutamine versus dopamine. Superior vena cava (SVC) flow was used as a measure of SBF at 3, 10, and 24 h (n = 106). Infants with low SVC flow randomized to dopamine or dobutamine. ⋯ Contractility was not improved by either inotrope at either dose. In conclusion, infants developing low SVC flow in the first day have worse myocardial contractility at 3 h. Neither inotrope increased contractility, but dopamine increased LV stress at 20 microg/kg/min.
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With increasing pressure support ventilation (PSV), a form of pneumatically triggered ventilation, there can be an increase in wasted inspiratory efforts (neural inspiratory efforts that fail to trigger the ventilator). With neurally adjusted ventilatory assist (NAVA), a mode of ventilation controlled by the electrical activity of the diaphragm (EAdi), synchrony should be maintained at high levels of assist. The aim of this study was to evaluate the response to increasing levels of PSV and NAVA on synchrony and diaphragm unloading in lung-injured rabbits. ⋯ Increasing NAVA levels reduced EAdi and Pdi-time products by 48% (p < 0.05) and 66% (p < 0.05). In contrast, increasing PSV did not reduce the diaphragm electrical activity-time product and increased the transdiaphragmatic pressure-time product (p < 0.05) due to the increased wasted efforts. We conclude that synchrony with the ventilator is an important determinant for diaphragm unloading.
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Cardiac output can be measured using a modified carbon dioxide Fick (mCO2F) method. A validation study was performed comparing mCO2F method-derived cardiac output (Q(mCO2F)) with invasively measured pulmonary blood flow. In seven randomly bred ventilated newborn lambs, cardiac output was manipulated by creating hemorrhagic hypotension. ⋯ The limits of agreement were -0.328 to 0.164 Lxmin(-1) (RA), -0.335 to 0.165 Lxmin(-1) (SVC), and 0.415 to 0.049 Lxmin(-1) (IVC). In conclusion, measurement of cardiac output with the mCO2F method is reliable and easily applicable in ventilated newborn lambs. For clinical use, the site of venous blood sampling is of minor importance.