Effect of early fluid resuscitation on the lung in a rat model of lipopolysaccharide-induced septic shock

W. Liu, L.P. Shan, X.S. Dong, X.W. Liu, T. Ma, Z. Liu

Department of Emergency, The First Affiliated Hospital of China Medical University, Shenyang, P.R. China. ZhiLiu001@hotmail.com

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• Pharmacology

BACKGROUND: Many clinical trials have showed that early fluid resuscitation can improve the prognosis and reduce the mortality rate of patients with septic shock. However, some experiments suggest that abundant fluid may injure the lung and other tissues.

AIM: To evaluate the protective effect of early fluid resuscitation and simultaneous norepinephrine treatment on lung function by using the rat model of lipopolysaccharide (LPS)-induced septic shock.

MATERIALS AND METHODS: Male Wistar rats were randomly divided into four groups: normal control group, septic shock control group, early fluid resuscitation treatment group, early fluid resuscitation and simultaneous norepinephrine treatment group. Blood gas, lactate, fluid volume, and dose of norepinephrine were recorded. Pathological change was observed by hematoxylin and eosin staining and transmission electron microscopy. The activities of hydroxyl radicals, MDA, SOD and MPO were detected by spectrophotometry. The expression of IL-6, IL-8, and TNF-alpha were determined with ELISA kits.

RESULTS: LPS could induce rats to suffer from acute lung injury in early stage of septic shock. Early fluid resuscitation could guarantee effective circulating blood volume and tissue perfusion pressure, improve microcirculatory derangements, increase oxygen partial pressure and oxygenation index, but have the tendency to aggravate pulmonary edema. Simultaneous norepinephrine treatment in early stage could decrease the fluid volume, alleviate the degree of pulmonary edema, reduce the expression level of pro-inflammatory mediators in the serum and BALF, and increase the oxygenation index.

CONCLUSIONS: Early fluid resuscitation and simultaneous norepinephrine treatment may be a superior alternative to protect lung injury secondary to septic shock.

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