Articles: extravascular-lung-water.
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Acute lung injury or acute respiratory distress syndrome (ALI/ARDS) in the course of sepsis is thought to result from increased pulmonary capillary permeability and resultant edema. However, when the edema is assessed at the bedside by measuring the extravascular thermal volume by transpulmonary dilution, some ALI/ARDS patients with sepsis may have normal extravascular lung water (EVLW). Conversely, a raised EVLW may be present even when criteria for ALI/ARDS are not met, according to GS Martin and colleagues in this issue of Critical Care. ⋯ Overhydration is particularly difficult to recognize. Additional diagnostics may be required to improve the delineation of pulmonary edema so as to redirect or redefine treatment and improve patient morbidity and, perhaps, mortality. Monitoring EVLW by single transpulmonary thermal dilution, for instance, might have a future role in this process.
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Comparative Study
Extravascular lung water in patients with severe sepsis: a prospective cohort study.
Few investigations have prospectively examined extravascular lung water (EVLW) in patients with severe sepsis. We sought to determine whether EVLW may contribute to lung injury in these patients by quantifying the relationship of EVLW to parameters of lung injury, to determine the effects of chronic alcohol abuse on EVLW, and to determine whether EVLW may be a useful tool in the diagnosis of acute respiratory distress syndrome (ARDS). ⋯ More than half of the patients with severe sepsis but without ARDS had increased EVLW, possibly representing subclinical lung injury. Chronic alcohol abuse was associated with increased EVLW, whereas lower EVLW was associated with survival. EVLW correlated moderately with the severity of lung injury but did not account for all respiratory derangements. EVLW may improve both risk stratification and management of patients with severe sepsis.
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Am. J. Respir. Crit. Care Med. · Feb 2005
Comparative StudyGene transfer of the Na+,K+-ATPase beta1 subunit using electroporation increases lung liquid clearance.
The development of nonviral methods for efficient gene transfer to the lung is highly desired for the treatment of several pulmonary diseases. We have developed a noninvasive procedure using electroporation to transfer genes to the lungs of rats. Purified plasmid (100-600 microg) was delivered to the lungs of anesthetized rats through an endotracheal tube, and a series of square-wave pulses were delivered via electrodes placed on the chest. ⋯ To demonstrate efficacy of this approach, the beta1 subunit of the Na(+),K(+)-ATPase was transferred to the lungs of rats with or without electroporation, and 3 days later, alveolar fluid clearance was measured. Animals electroporated with the beta1 subunit plasmid showed a twofold increase in alveolar fluid clearance and Na(+),K(+)-ATPase activity as compared with animals receiving all other plasmids, with or without electroporation. These results demonstrate that electroporation is an effective method to increase clearance by introducing therapeutic genes (Na(+),K(+)-ATPase) into the rat lung.
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The resolution of alveolar edema is regulated by active sodium and chloride transport across the pulmonary epithelium, including alveolar epithelial type I and II cells as well as distal airway epithelia. Catecholamine-dependent mechanisms can markedly upregulate alveolar fluid clearance even under pathological conditions, an effect that is mediated by both epithelial sodium channel (ENaC) and cystic fibrosis transmembrane conductance regulator (CFTR). ⋯ However, there is some experimental and clinical evidence that cAMP stimulation could accelerate the resolution of pulmonary edema in the presence of acute lung injury. Clinical trials are needed to test this potential therapeutic strategy in patients with acute lung injury.
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Critical care medicine · Jan 2005
Increases in lung and brain water following experimental stroke: effect of mannitol and hypertonic saline.
Pulmonary edema is a serious condition following brain injury of diverse etiologies, including large hemispheric infarctions. We have previously shown that treatment with hypertonic saline attenuates cerebral edema associated with experimental ischemic stroke. In a well-characterized animal model of large ischemic stroke, we tested the hypotheses that lung water increases following cerebral ischemia and determined the effects of osmotherapy with hypertonic saline and mannitol on total lung water, as well as on cerebral edema. ⋯ In a well-characterized animal model of large ischemic stroke, total lung water content increases, which is likely neurogenic in origin. Attenuation of stroke-associated increases in lung and brain water content with continuous infusion of hypertonic saline may have therapeutic implication in the treatment of cerebral and pulmonary edema following ischemic stroke.