Critical care medicine
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Critical care medicine · May 1991
Unaccounted for anion in metabolic acidosis during severe sepsis in humans.
To quantitate the contribution of lactate, phosphate, urate, total serum proteins, and unidentified anions to the anion gap in patients with severe sepsis. ⋯ These data indicate that lactic acidosis does not entirely account for the metabolic acidosis during severe sepsis. Furthermore, the increased corrected anion gap suggests the presence of an unidentified anion (or anions) that is (or are) responsible, in large part, for the development of metabolic acidosis in patients with sepsis.
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This review article examines the pathophysiology of septic shock, with special attention to the concept of supply-dependent consumption and the implications this concept has for therapy. Patients with septic shock require higher levels of oxygen delivery (DO2) to maintain aerobic metabolism. When DO2 is inadequate, peripheral tissues switch to anaerobic metabolism and oxygen consumption decreases. ⋯ Maximizing DO2 is an important part of the hemodynamic resuscitation of patients with septic shock. To achieve this goal, intravascular volume must be restored and the myocardial depression associated with sepsis must be treated to optimize cardiac output. The normalization of arterial lactate concentration is a reasonable goal of resuscitative efforts.
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To review clinical studies of oxygen transport in cardiogenic and septic shock. ⋯ There are widely differing oxygen transport patterns in cardiogenic and septic shock that may have implications for therapy.
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Critical care medicine · May 1991
ReviewExperimental models of pathologic oxygen supply dependency.
Pathologic oxygen supply dependency is an abnormal situation in which oxygen uptake (Vo2) varies directly with oxygen delivery. Its presence in patients with adult respiratory distress syndrome and/or sepsis has been associated with particularly high mortality rates that may be the result of tissue hypoxia that causes multiple organ failure. The evidence for this association has been indirect because we cannot use invasive methods that would be necessary to verify or disprove the hypothesis. ⋯ Regional measurements have shown that gut Vo2 decreases before other areas, particularly skeletal muscle. Lactate measurements alone were shown not to be sufficient proof of tissue hypoxia. More direct measurements of actual energy states and tissue Po2 are indicated for future research efforts.
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Critical care medicine · May 1991
Use of continuous noninvasive measurement of oxygen consumption in patients with adult respiratory distress syndrome following shock of various etiologies.
To describe the patterns of cardiac index, oxygen delivery (DO2), oxygen consumption (VO2), and oxygen deficit (or excess) and to compare invasive and noninvasive monitoring systems for evaluation of these oxygen transport patterns. ⋯ Monitoring of VO2 and DO2 variables is useful for evaluation of tissue oxygenation and titration of therapy in critically ill patients. Noninvasive monitoring of VO2 values are in good agreement with VO2 values calculated from invasive measurements of cardiac index. The increased DO2 and VO2 values are not attributable to mathematical coupling of erroneous cardiac index values.