Phenobarbital (PB) brain and blood concentrations were measured together with brain and blood pH in newborn piglets before and at the end of seizure activity induced by pentylenetetrazol or bicuculline. Seizures induced a significant elevation of arterial blood pressure and profound changes in the blood gases and in the acid-base balance, with a marked reduction in brain tissue pH. Despite an intense brain acidosis, however, and a significant rise in blood/brain [H+] gradient, phenobarbital brain concentrations were not reduced during seizures but, on the contrary, were increased in 7 of 11 piglets. These data suggest that contrary to the pH partition hypothesis, brain uptake of PB is concomitantly increased during seizures and brain acidosis.

Animals↗

PubMedDate not supplied

Persistence of impaired autoregulation of cerebral blood flow in the postictal period in piglets.

Cerebral blood flow (CBF) autoregulation was evaluated in the postictal period in unanesthetized term newborn piglets with a mean age of 5.7 +/- 3 days. Seven animals (group 1) received 1 mg/kg bicuculline to induce brief generalized seizures, and six control animals (group II) received saline. Twenty to 90 min after the end of seizure activity in group I or saline injection in group II, CBF was measured by the radioactive labeled microspheres method at three levels of mean arterial blood pressure (MABP) obtained by controlled blood withdrawal within the normal range for autoregulation. In the postictal period, baseline CBF was higher in group I than in group II (85 +/- 21 vs. 48 +/- 7 ml/min/100 g, p less than 0.001). During hypotension, total CBF was positively correlated with variations of MABP in group I (r = 0.739, p less than 0.01) but not in group II. Regional CBF showed the same correlation with MABP. These data show that after seizures in piglets, the rise in CBF is associated with a persistent impairment of CBF autoregulation. These hemodynamic alterations may be relevant in the pathogenesis of hemorrhagic or ischemic brain lesions.

Animals↗

PubMedDate not supplied

[The choice between theophylline and caffeine in the treatment of apnea in premature infants].

In a double blind study, two comparable groups (each n = 10) of premature infants less than 34 weeks of gestational age, with idiopathic apnea were given an IV treatment of either theophylline or caffeine. The loading doses were respectively 6 and 10 mg/kg and the maintenance doses were 2 and 1.25 mg/kg every 12 hours. In both groups, apneas greater than or equal to 15 s. with or without bradycardia were similarly reduced (p less than 0.01). Both drugs increased significantly the respiratory rate. Compared to caffeine, theophylline induced a significant acceleration of heart rates, an increase in urinary sodium excretion, more frequent gastrointestinal intolerance and behavioral changes. Plasma concentrations of theophylline were less stable than those of caffeine. These data suggest that a single daily dose of caffeine should be preferentially used in the treatment of idiopathic apneas of prematurity.

Caffeine↗

PubMedDate not supplied

[Respiratory distress in newborn infants: study of PO-2; therapeutic indications].

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Bicarbonates↗