Journal of critical care
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Journal of critical care · Mar 1993
Oxygen uptake-oxygen delivery alterations in the isolated liver after hydrogen peroxide challenge.
Acute, diffuse lung injury is frequently complicated by systemic organ injury and alterations in the relationship between oxygen uptake (VO2) and oxygen delivery (QO2). In this regard, systemic organ neutrophil accumulation and morphologic alterations consistent with systemic organ injury often occur in nonpulmonary organs in these settings. However, whether VO2-QO2 matching is also altered in these injured systemic organs remains unproven. ⋯ In addition, VO2 was lower for any given level of QO2 in the H2O2-injured livers compared with the control livers (P < .01). Finally, liver extravascular water content was increased in H2O2-injured livers compared with the control livers (0.79 +/- 0.02 v 0.71 +/- 0.05; P < .05). These observations indicate that H2O2, a product of neutrophil oxidative metabolism, is capable of producing both morphologic changes as well as gas exchange alterations in the isolated, perfused liver.
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Journal of critical care · Mar 1993
Oxygen kinetics during liver transplantation: the relationship between delivery and consumption.
In anesthetized humans, oxygen consumption is independent of oxygen delivery above a critical threshold. Below this critical level, lactic acid is a marker of anaerobic metabolism and tissue oxygen debt, and heralds a supply dependency of oxygen consumption. The goal of this study was to determine whether a threshold value for oxygen delivery below which oxygen consumption becomes supply dependent can be identified in patients with normal, impaired, or absent liver function. ⋯ Lactate increased in both groups during surgery, but was significantly higher in nonsurvivors (6.6 +/- 0.4 mmol/L) than in survivors (4.6 +/- 0.1 mmol/L) (P < .05). With similar changes for oxygen delivery and oxygen consumption during increased lactate levels we could not identify a clear supply dependency of oxygen consumption in survivors and nonsurvivors during liver transplantation. We conclude that the interpretation of blood lactate levels during circulatory shock can be biased due to a reduced lactate clearance in patients with impaired liver function, unrelated to the status of the relationship between oxygen delivery and consumption.(ABSTRACT TRUNCATED AT 250 WORDS)