Articles: respiratory-distress-syndrome.
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Despite numerous advances, the mortality from adult respiratory distress syndrome (ARDS) remains high. Traditional ventilator management in ARDS has been to maintain normal PaCO2 by positive pressure ventilation (PPV). However, high levels of PPV may worsen the lung injury by alveolar overdistension. Permissive hypercapnia (PHC) has been proposed as an alternative method of ventilation, but hypercapnia may affect the hemodynamics of a hyperdynamic, critically ill patient. The purpose of this study was to determine the effect of PHC on ventilator requirement, arterial oxygenation, and hemodynamic performance in patients with severe ARDS. ⋯ Permissive hypercapnia by V(t) reduction: (1) decreased Ve, PAP, and Pplat without a change in mean airway pressure, static compliance or arterial oxygenation; (2) caused a mild partially compensated acidosis; and (3) does not adversely affect pulmonary vascular resistance, systemic vascular resistance, cardiac index, or systemic oxygen delivery and consumption.
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Comparative Study
A functional and morphologic analysis of pressure-controlled inverse ratio ventilation in oleic acid-induced lung injury.
To compare volume-controlled ventilation (VCV PEEP) with pressure-controlled inverse ratio ventilation (PCIRV) at equal levels of end-expiratory pressure. ⋯ PCIRV was no better than VCV with similar PEEP levels in alveolar recruitment and aeration of the lung tissues or in oxygenating the blood. Cardiac output was lower with PCIRV than with VCV, causing lower oxygen delivery to peripheral tissues. PCIRV does allow for a reduction in minute ventilation and for lowering peak airway pressure.
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Critical care medicine · Sep 1994
Airway pressure measurements during high-frequency positive pressure ventilation in extremely low birth weight neonates.
Evaluation of a modified, computer-controlled, shutter method to determine the complete intrapulmonary pressure course and to ascertain the expiratory time constant for the respiratory system during high-frequency positive pressure ventilation. ⋯ The computer-controlled shutter method is noninvasive and applicable without impairment, even in preterm neonates with birth weights of < 1000 g. This method provides important information to optimize respiratory therapy, particularly knowledge of the individual time constant. To avoid inadvertent positive end-expiratory pressure and gas trapping, expiratory time should be > 4 time constants.
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Critical care medicine · Sep 1994
Clinical experiences with high-frequency oscillatory ventilation in newborns with severe respiratory distress syndrome.
To generate hypotheses about which subgroups of newborns with severe respiratory distress syndrome might benefit most from high-frequency oscillatory ventilation. ⋯ As a result of our analysis, we hypothesize that term newborns with severe respiratory distress syndrome complicated by persistent pulmonary hypertension and hypercarbia can benefit from high-frequency oscillatory ventilation. Premature neonates with ventilation-induced lung injury are not likely to respond to high-frequency oscillatory ventilation.
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It is well known that endotoxin causes acute lung injury resulting in adult respiratory distress syndrome. Numerous cellular and humoral factors such as macrophages, neutrophils, platelets, and inflammatory mediators (e.g., activated complements, cytokines, and arachidonic acid metabolites) are thought to play a pivotal role in the pathogenesis of endotoxin-induced lung injury. Furthermore, pulmonary edema in acute lung injury is associated with an increase in vascular permeability that may arise from a perturbation of the endothelial cell surface membrane. Lidocaine has been shown to inhibit function of these cells and stabilize cell membranes. The aim of the current study was to determine whether pretreatment with intravenous lidocaine could attenuate acute lung injury induced by endotoxin in rabbits. ⋯ These results suggest that intravenous lidocaine pretreatment has a prophylactic effect on endotoxin-induced lung injury in rabbits. However, further studies are required to investigate the therapeutic (as an early posttreatment) effect of the drug given after lung injury because rabbits in the current study received lidocaine before endotoxemia.