Shock : molecular, cellular, and systemic pathobiological aspects and therapeutic approaches : the official journal the Shock Society, the European Shock Society, the Brazilian Shock Society, the International Federation of Shock Societies
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Resuscitation using small volumes of hypertonic saline solutions normalizes cardiac output without fully restoring arterial pressure. This study compared the efficacy of either 7.2% saline/10% dextran 60 (HSDex) or the identical sodium load of normal saline (NS) to improve regional myocardial blood flow (MBF), contractile function, and oxygen metabolism in the presence of a critical coronary stenosis. Fourteen anesthetized, open-chest pigs (25 +/- 3.6 kg) were instrumented to assess left anterior descending coronary artery (LAD) flow, post-stenotic oxygen, and lactate metabolism, regional myocardial segment shortening (SS, sonomicrometry), and MBF (radioactive microspheres). ⋯ MBF increased above baseline values with either solution in non-stenotic while it remained at shock levels in post-stenotic myocardium, where ischemia persisted as evidenced by lactate production and depressed SS. Neither in non-stenotic nor in post-stenotic myocardium was the epi-endocardial flow ratio normalized upon resuscitation with HSDex or NS. We conclude that in the presence of a flow-limiting coronary stenosis, initial fluid resuscitation with both HSDex and the identical sodium load of NS failed to restore perfusion pressure, redistributed MBF in favor of normally perfused myocardium, and did not reverse ischemia in post-stenotic myocardium.
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The aim of this study was to investigate mucosal pH and lactate production in a porcine model of ischemia/reperfusion and sepsis using both tonometry and a technique for segmental intestinal perfusion. Eighteen pigs (17-23 kg) were anesthetized and mechanically ventilated. They were divided into three groups and followed for 4 h. ⋯ A good association between pHi and lactate production was seen in ischemia/reperfusion. However, in sepsis, lactate in superior mesenteric venous blood or in intestinal perfusate did not increase, despite the fall in pHi. The mechanism causing ischemic mucosal injury has different characteristics in sepsis and in ischemia caused by arterial occlusion.