[Mechanical ventilation in rats]. / Ventilación mecánica en ratas.

In order to create an experimental model of mechanical ventilation that allows functional respiratory studies and different studies related to thorax surgery in small animals, young adult Sprague-Dawley male rats were anesthetised with sodium thiopental and a tracheostomy with a tephlonated catheter was performed. The carotid artery was canulated for arterial blood gas samples, and the cardiovascular system was controlled permanently. A continuous flow time cicled neonatal ventilator, Loosco Amsterdan Infant Ventilator M.K.2, was used for mechanical ventilation. Conventional ventilation with different volumes and pressures were tested. Good adaptation and tolerance and normal blood gases were found with a rate of 60/min; flow rate 0.2 l/min; I:E 1:2; PEED 0 cm H2O; PIP 6.7 +/- 0.5 (mean +/- SD) cm H2O and sharp waves. We conclude that with these very old neonatal ventilators it is possible to ventilate very small experimental animals easily, and allow to small laboratories to do respiratory functional studies or experimental surgery of the thorax.

[Monitoring theophylline in premature newborn infants]. / Monitorización de la teofilina en el recién nacido prematuro.

In order to defined the PO theophylline dose which produced effective theophylline concentrations between 4-10 micrograms/ml in prematures babies, we analized the theophylline pharmacokinetic of 6 adequate weight for gestational age female prematures, aged 31-34 gestational weeks, to which we administered PO 5 mg/kg of theophylline as the attack dose, following by a PO maintained dose of 2.5 mg/kg/12 h. In steady-state we did the pharmacokinetic studies after the administration of one dose. We found that only maintenance doses of 2.5 mg/kg/12 h produced therapeutic theophylline concentrations. Considering the pharmacokinetic data, we conclude that PO maintenance dose of 3 mg/kg/12 h of theophylline will be necessary to reach effective theophylline concentration.

[Pharmacokinetics of theophylline in children with acute asthmatic crisis]. / Farmacocinética de la teofilina en niños con crisis asmática aguda.

In order to defined the theophylline dose which produce effective theophylline concentrations with less number of plasmatic controls, we analyzed the theophylline pharmacokinetics of 18 boys and girls between 3-12 year olds of Tarragona, to which we administered 6 mg/kg/6 h of aminophylline by IV intermittent infusion (30 min), following by rapid-release PO aminophylline at the same dose and intervals. In steady-state we did the pharmacokinetic studies at 1 h, 4 h and 6 h after the administration of one dose. The maintenance dose obtained was administered PO as slow-release theophylline, with later controls of theophylline concentration. We found that maintenance dose of 24.1 +/- 4.7 mg/kg/day (mean +/- SD) allowed theophylline concentration between therapeutic levels in the population studied.