Critical care medicine
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Critical care medicine · Jan 1993
Randomized Controlled Trial Comparative Study Clinical TrialAlterations in feline tracheal permeability after mechanical ventilation.
Previous investigations of ventilator-induced airway injury focused on histopathologic changes associated with various ventilators and strategies for their use. We hypothesized that mechanical ventilation is associated with alterations in tracheal epithelial permeability, and designed a study using an animal model to evaluate changes in tracheal epithelial permeability after administering different types of mechanical ventilation to test this hypothesis. ⋯ Mechanical ventilation was associated with increases in tracheal permeability to large and small nonionic molecules. These changes occurred with all studied ventilators, used as they are clinically. Permeability changes paralleled ventilatory rate changes.
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Critical care medicine · Jan 1993
Comparative StudyPharmacokinetics of exogenous epinephrine in critically ill children.
This study was designed to determine the steady-state plasma concentrations and clearance rates of epinephrine in critically ill children, to examine if epinephrine pharmacokinetics conform to a linear model, and to compare epinephrine clearance rates with clearance rates of dopamine and dobutamine. ⋯ Epinephrine infusions produce pharmacologic plasma concentrations of epinephrine in critically ill children. The plasma concentration of epinephrine correlates with the infusion rate, suggesting linear pharmacokinetics. Epinephrine clearance rates in critically ill children appear to be lower than the reported clearance rates in healthy adults. The clearance rates of two other inotropic catecholamines, dopamine and dobutamine, are significantly correlated with the clearance rate of epinephrine.
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a) To quantify the use of do-not-resuscitate orders in a tertiary care children's hospital; and b) to characterize the circumstances in which such orders are written. ⋯ Do-not-resuscitate orders in pediatric patients are written more often in older than younger hospitalized children who die. Most do-not-resuscitate orders are written for patients who are receiving aggressive medical therapy in the ICU.
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To describe the physiologic mechanisms of ventilator-induced lung injury and to define the major ventilator and host-dependent risk factors that contribute to such injury. ⋯ Ventilation with high tidal volumes can increase vascular filtration pressures; produce stress fractures of capillary endothelium, epithelium, and basement membrane; and cause lung rupture. Mechanical damage leads to leakage of fluid, protein, and blood into tissue and air spaces or leakage of air into tissue spaces. This process is followed by an inflammatory response and possibly a reduced defense against infection. Predisposing factors for lung injury are high peak inspiratory volumes and pressures, a high mean airway pressure, structural immaturity of lung and chest wall, surfactant insufficiency or inactivation, and preexisting lung disease. Damage can be minimized by preventing overdistention of functional lung units during therapeutic ventilation.
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Critical care medicine · Jan 1993
Synchronous mechanical ventilation of the neonate with respiratory disease.
To assess the importance of synchronization of mechanical ventilation with spontaneous respiratory efforts in mechanically ventilated neonates. The actions of this synchronization on ventilation, oxygenation, and BP variation were assessed. ⋯ Synchronous ventilation can be readily applied to most ventilated neonates. It improves ventilation, and results in a marked reduction in BP variation, which may have implications for reducing the risk of intraventricular hemorrhage.