Efficacy of bronchodilators administered by nebulizers versus spacer devices in infants with acute wheezing.

The aim of this study was to compare the response of infants with acute wheezing to treatments with inhaled terbutaline when administered by nebulizer or by metered-dose inhaler and spacer device (MDI-spacer). Thirty-four infants between the ages of 1 and 24 months who were seen in our emergency department for acute wheezing were studied in a double-blind, randomized trial. The participants received two treatments of terbutaline at 20-min intervals, either by a nebulizer (2 mg/dose in 2.8 mL of 0.9% saline solution) or by an MDI-spacer device (0.5 mg/dose). The outcome measure was a clinical score, based on respiratory rate, degree of wheezing, retractions, degree of cyanosis, color, and pulse oximetry data measured before treatment, 20 min after the first treatment, and again 20 min after the second treatment. There was no difference in the rate of improvement in the clinical score between infants who received terbutaline by nebulizer and those who received it by MDI-spacer. We conclude that MDI-spacers and nebulizers are equally effective means of delivering beta-2 agonists to infants and small children with acute wheezing.

[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.

[Pulmonary complications during parenteral feeding via percutaneous silicon catheters]. / Complicaciones pulmonares durante la nutrición parenteral con catéteres siliconados percutáneos.

Percutaneous fine bore silicone central catheters are frequently used in sick full term newborns and in low birth weight premature infants; although their use has some risks. We report two cases of pleural effusion in two prematures of 34 and 33 weeks gestation and birth weight of 1,510 and 1,650 g, respectively; and one case neumonitis in a newborn of a 38 weeks gestation and 2,730 g birth weight. All of them have in common same initial clinical sign: increase mucus secretion of the upper airway a few hours after the beginning of parenteral nutrition using the type of catheter mentioned with the tip abnormally located in pulmonary artery. These complications are probably related to endothelial injury of very slow flow vessels due to the high osmolarity and low pH of the parenteral solutions used; which probably, in turn, produce thrombosis and vascular perforation, and/or extravasation. We suggest to suspect a pulmonary artery abnormally located catheter in patients receiving parenteral nutrition who increase upper airway mucus secretion. The rapid correction of the position would prevent major complications.

[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.