[Inadequate secretion of atrial natriuretic peptide in children with acute brain injury]. / Secreción inadecuada de péptido natriurético auricular en niños con daño cerebral agudo.

OBJECTIVE: Fluid and electrolyte disturbances are frequent after acute brain damage. Atrial natriuretic peptide (ANP), which can also be found in brain tissue, could be a hormone implicated in such disorders (cerebral salt wasting syndrome). PATIENTS AND METHODS: Plasma ANP levels were analyzed in 50 children with acute neurological deterioration (secondary to traumatic, infectious, convulsive tumor or vascular disorders) evaluated according to the modified Glasgow Coma Scale (GCS). Hemodynamic stability was determined by standard monitoring. ANP, renin and aldosterone levels were determined by RIA and the results compared with a control group of healthy children. RESULTS: There was an increase in ANP levels in children with brain injury in comparison to the control group (p < 0.001), but not in children under one year of age. Renin and aldosterone were also significantly increased in this group of patients, with no difference in ANP, renin or aldosterone level found in function of their GCS score. All patients were hemodynamically stable and no correlation between hemodynamic and hormone variables was seen. Mechanical ventilation did not influence the hormone levels. CONCLUSIONS: There is an important increase in ANP levels in patients with acute neurological pathologies, but it was not related to the hemodynamic condition and its importance has yet to be established. One of its possible consequences is a secondary hypotonic/hypovolemic condition, a potentially dangerous event for the patient with intracranial hypertension that needs immediate treatment. Differentiation of this syndrome from inappropriate vasopressin secretion could be very important in children with acute brain injury.

Relationship between hemodynamic changes and blood hormone concentrations after cardiac surgery in children with congenital heart disease.

OBJECTIVES: To evaluate changes in atrial natriuretic factor in relation to modifications in hemodynamic variables, and to evaluate hormones determining salt and water metabolism after heart surgery in children with congenital heart disease. DESIGN: Prospective study. SETTING: Medical-surgical pediatric intensive care unit (ICU) in a tertiary referral center. PATIENTS: Sixty-five infants and children admitted to the pediatric ICU with congenital heart disease who underwent cardiac surgery with extracorporeal circulation. The control group consisted of 48 children undergoing noncardiac surgical interventions, without a history of cardiac disease and with normal hemodynamic variables. MEASUREMENTS AND MAIN RESULTS: Patients with congenital heart disease were distributed into two groups, according to hemodynamic variables. Group 1 consisted of patients with normal pulmonary blood flow (pulmonary/systemic blood flow ratio of < 2, pulmonary arterial systolic pressure of < 35 mm Hg, pulmonary arterial systolic pressure/aortic systolic pressure ratio of < 0.35). Group 2 consisted of patients with relatively increased pulmonary blood flow (pulmonary/systemic blood flow ratio of > 2.5, pulmonary arterial systolic pressure of > 65 mm Hg, pulmonary arterial systolic pressure/aortic systolic pressure ratio of > 0.75). Blood samples were obtained 24 hrs before, and 24 and 48 hrs after surgery. Hormone determinations included plasma concentrations of atrial natriuretic factor, vasopressin, plasma renin activity, corticotropin, cortisol, and aldosterone. Hemodynamic measurements were recorded simultaneously with blood sampling. Twenty-four hours before surgery, plasma concentrations of atrial natriuretic factor were higher in congenital heart disease patients than in the control group (67.36 +/- 93.44 vs. 15.11 +/- 8.29 pmol/L) (p < .001). Plasma concentrations of atrial natriuretic factor were 57.12 +/- 82.20 and 74.63 +/- 101.03 pmol/L in groups 1 and 2, respectively. Before surgery, in group 2 patients, there was a significant correlation between mean right atrial pressure and atrial natriuretic factor (r2 = .64; p < .001), vasopressin (r2 = .55; p < .001), cortisol (r2 = .43; p < .01), corticotropin (r2 = .53; p < .01), and aldosterone (r2 = .57, p < .001). None of these correlations were observed in group 1. However, 24 hrs after surgery, we found a significant correlation between diastolic blood pressure and atrial natriuretic factor in group 1. Plasma concentrations of atrial natriuretic factor did not change significantly after surgery. After surgery, the correlation between mean right atrial pressure and the various hormone concentrations persisted at 24 hrs (p < .05), but not at 48 hrs. Twenty-four hours after surgery, patients with a central venous pressure of > 7 mm Hg showed higher concentrations of atrial natriuretic factor than those patients with central venous pressures of < 7 mm Hg (p < .05). However, there was a large overlap of atrial natriuretic factor values between the two groups. CONCLUSIONS: Patients with congenital heart disease have increased plasma concentrations of atrial natriuretic factor. During the early postoperative period, in patients with a more severe degree of congenital heart disease, the increase in central venous pressure correlated with higher plasma concentrations of atrial natriuretic factor. High pulmonary blood flow was associated with an increase in plasma renin activity and serum aldosterone, and an increased secretion of atrial natriuretic factor.

[Effects of competitive physical exercise on neuroendocrine response and interleukin-6 liberation in children]. / Repercusión del ejercicio físico competitivo en la respuesta neuroendocrina y liberación de interleuquina-6 en niños.

OBJECTIVE: The purpose of this study was to evaluate the effects of physical activity on the secretion of cortisol, melatonin and interleukin-6 (IL-6) in children. PATIENTS AND METHODS: A controlled prospective study was carried out. Based on anthropometrical measurements and physical examination, which excluded those with an organic pathology or that were further than one standard deviation from the 50th percentile, 74 male children aged 6 or 7 years were included in this study. Forty-one children from a public school (PS) and 33 children from a soccer sport school (SS) were selected and asked to perform three different physical activities. A score was made to evaluate their performance and both before and after physical activity salivary samples were obtained to measure cortisol, melatonin and IL-6 concentrations. RESULTS: The children in the SS group had a better global physical performance score than those from the PS. There were no statistically significant differences in biochemical parameters between the two groups before and after exercise. There was a rise in the cortisol, melatonin and IL-6 levels after physical activity in both groups. The increment in melatonin levels after exercise was significantly higher in the SS group. There was a strong positive correlation between the rise of cortisol and IL-6 levels after exercise. CONCLUSIONS: In our study, controlled physical competitive activity in children 6 or 7 years of age showed no negative repercussion on cortisol secretion or in the liberation of IL-6.