Journal of critical care
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Journal of critical care · Mar 1994
Comparative StudyThe effects of intravenous L-arginine supplementation on systemic and pulmonary hemodynamics and oxygen utilization during group B streptococcal sepsis in piglets.
In these investigations, three questions were addressed. First, to what extent did inhibition of endothelium-derived relaxation factor (EDRF) mimic the hemodynamic disturbances noted in a piglet model of neonatal group B streptococcal (GBS) sepsis? Second, to what extent would an attempt to augment EDRF production reverse the hemodynamic effects of continued GBS infusion in septic piglets? Third, to what extent would an attempt to augment EDRF production affect hemodynamics in piglets who were not septic. ⋯ EDRF inhibition with NNLA appeared to model GBS infusion partially but not completely. L-ARG appeared to produce desirable hemodynamic effects during GBS sepsis when compared with the consequences of ongoing GBS infusion without L-ARG. Given the constellation of increased pulmonary and systemic vascular resistance often observed during neonatal GBS sepsis in human infants, all these effects of L-ARG, if extrapolated from our piglets to the clinical arena, would appear to be beneficial. Particularly in the context of deleterious consequences resulting shunting or right ventricular decompensation from increased afterload), L-ARG administration might prove clinically useful.
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Journal of critical care · Mar 1994
Comparative StudyEffects of dobutamine and prostacyclin on cerebral blood flow velocity in septic patients.
Both dobutamine and prostacyclin (PGI2) have been used to increase oxygen delivery in septic patients, but their effects on cerebral blood flow have not been well studied. ⋯ Dobutamine and PGI2 at the administered doses exert different effects on arterial pressure and middle cerebral artery flow velocity in septic patients. According to these data, dobutamine increases cerebral oxygen delivery more than PGI2.
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Journal of critical care · Mar 1994
Comparative StudyThe effect of adrenergic agonists on the systemic response to hemorrhage.
Systemic blood loss elicits a variety of reflex cardiovascular responses, which preserve cardiac output as possible and preserve arterial blood pressure when cardiac output decreases. When compensatory venoconstriction is exhausted, hemorrhage reduces oxygen delivery (QO2), and systemic vasoconstriction competes with local metabolic vasodilation to preserve tissue oxygen uptake (VO2). Through their effects on vascular tone and blood flow distribution, adrenergic agents might interfere with the physiological responses to reduced O2 delivery. This study was designed to determine the effects of dobutamine and norepinephrine on oxygen extraction and systemic vascular resistance during progressive hemorrhage. ⋯ Norepinephrine and dobutamine appear to block reflex vasoconstriction, and mechanistic explanations for this finding remain speculative. Despite inhibition of reflex vasoconstriction, neither dobutamine nor norepinephrine significantly impaired oxygen extraction during hemorrhage.
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Journal of critical care · Dec 1993
Comparative StudyEffect of pretreatment with anticonvulsants on theophylline-induced seizures in the rat.
Seizures, often with fatal outcome, are a manifestation of pronounced theophylline toxicity. Prodromal symptoms are not always apparent, and the seizures are reported to be, in certain cases, refractory to treatment with anticonvulsant drugs. The purpose of this investigation was to examine, by an established animal model, which of the commonly used anticonvulsants can reduce the central nervous system sensitivity to theophylline neurotoxicity and what should be the preferred treatment in cases in which theophylline toxicity is anticipated. ⋯ Theophylline concentrations in the cerebrospinal fluid, brain, and serum were assayed by a high-performance liquid chromatography method. It was found that pretreatment with either clonazepam, diazepam, phenobarbital, or valproic acid increased the central nervous system thresholds to the theophylline-induced seizures, whereas phenytoin and magnesium sulphate did not attenuate the sensitivity of the brain to the stimulatory action of this widely used bronchodilator. Therefore, whenever theophylline toxicity is suspected, treatment with either diazepam, clonazepam, phenobarbital, or valproic acid can reduce the hazard associated with theophylline-induced seizures.
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Journal of critical care · Dec 1993
Randomized Controlled Trial Clinical TrialSafety and efficacy of intravenous immunoglobulin prophylaxis in pediatric head trauma patients: a double-blind controlled trial.
Infection is one of the major complications of severe head trauma in children. To assess whether intravenous immunoglobulin (IVIg) decreases the incidence of secondary infection after head injury in children, a randomized, double-blind trial was performed. Thirty-three children (mean age, 6.67 years; mean injury severity score, 32.8; mean Glasgow coma score, 6.1) with severe head injuries were enrolled; 1 child was excluded, 18 received IVIg, and 14 received the placebo preparation. ⋯ There was no difference in the number of days on mechanical ventilation or in number of hospital days. There were no side effects. It is concluded that prophylactic administration of commercial IVIg at a dose of 400 mg/kg, although safe, had no effect on the incidence of secondary infections in children with severe head injuries.