Critical care medicine
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Critical care medicine · Feb 1993
Association between gastric intramucosal pH and splanchnic endotoxin, antibody to endotoxin, and tumor necrosis factor-alpha concentrations in patients undergoing cardiopulmonary bypass.
To determine the association between gastric intramucosal pH, a minimally invasive marker reflecting the adequacy of oxygen delivery to the gastrointestinal tract, and splanchnic endotoxin, antibody to endotoxin, and tumor necrosis factor (TNF)-alpha concentrations in patients undergoing cardiopulmonary bypass. ⋯ These observations are consistent with the hypothesis that impaired gut-barrier function is responsible for endotoxemia occurring during cardiopulmonary bypass. It is unclear whether increased mucosal permeability and mucosal acidosis are causally related phenomena or simply independent markers of damage to gut epithelium.
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To review the effects of endotoxemia on the major organ systems of the body and discuss potential mechanisms of tissue injury. ⋯ No single agent can yet be implicated as the common mediator of endotoxin-induced organ injury. Endotoxin initiates the elaboration of a cascade of secondary mediators that amplify the response to the initial insult. The relative importance of individual agents as mediators of the response to endotoxin varies with the experimental model studied.
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To provide an overview of the splanchnic hemodynamic response to circulatory shock. ⋯ While angiotensin II has been viewed primarily as the mediator responsible for the increased total vascular resistance seen during (and after) cardiopulmonary bypass, it may also cause the disproportionate decrease in mesenteric perfusion, as measured in human subjects by intraluminal gastric tonometry and galactose clearance by the liver, as well as the consequent development of the multiple organ failure syndrome seen in 1% to 5% of patients after cardiac surgery.
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To remind practitioners of the conventional goals of resuscitation of overt hypotensive or uncompensated shock ("ABC," for airway, breathing, and circulation) and to introduce additional goals, represented by successive letters of the alphabet, to aid clinicians in recognizing the persistence of compensated shock in the splanchnic organs and in achieving more complete resuscitation by eliminating inadequate tissue perfusion in these organs. ⋯ In traumatic and septic shock, multiple system organ failure is associated with a persistent state of compensated shock in which hypotension and oliguria are corrected, but in which inadequate perfusion persists in the splanchnic organs and especially in the mucosal lining of the gut. The additional goals recommended include "D" for increasing the delivery of oxygen to levels that meet the metabolic demand by all tissues in the body, especially those tissues within the splanchnic circulation, and "E" for ensuring extraction and utilization of oxygen by the tissues. Future needs for goals that address reperfusion injury, translocation of bacterial toxins, and the release of toxic mediators are also considered.