Interrelationship between blood and tissue lactate in a general intensive care unit: A subcutaneous adipose tissue microdialysis study on 162 critically ill patients
“…Tissue values may be influenced by the centralization of the circulation or by a stress-induced (i.e., non-ischemic) increase in lactate [35]. The interpretation of lactate values [12] and the L/P ratio [21] may also be guided by using the studies of patients with septic shock. In those studies, the highest tissue lactate values preceded the highest serum lactate values by 4 hours and the L/P ratio decreased in reaction to transfusion.…”
Section: Discussionmentioning
confidence: 99%
“…However, normal serum lactate values do not provide any information about the regional state of tissues. Patients in shock exhibit a difference in the level of lactate between the tissues and the blood [12]. The most important value is the lactate/pyruvate (L/P) ratio in the extracellular fluid, which serves as a timely marker of emerging ischemia and allows for the monitoring of hemorrhagic shock [13,14].…”
BackgroundTraumatic hemorrhagic shock resulting in tissue hypoxia is a significant cause of morbidity and mortality in polytraumatized patients. Early identification of tissue hypoxia is possible with microdialysis. The aim of this study was to determine the correlation between a marker of tissue hypoxia (L/P; lactate to pyruvate ratio) and selected parameters of systemic oxygen delivery (Hb; hemoglobin) and oxygen extraction (ScvO2; central venous oxygen saturation). We also investigated the severity of tissue hypoxia over the course of care.MethodsAdult patients with traumatic hemorrhagic shock were enrolled in this prospective, observational study. Microdialysis of the peripheral muscle tissue was performed. Demographic data and timeline of care were collected. Tissue lactate, pyruvate, glycerol, glucose levels, hemoglobin, serum lactate and oxygen saturation of the central venous blood (ScvO2) levels were also measured.ResultsThe L/P ratio trend may react to changes in systemic hemoglobin levels with a delay of 7 to 10 hours, particularly when systemic hemoglobin levels are increased by transfusion. Decrease in tissue L/P ratio may react to increase in ScvO2 with a delay of up to 10 hours, and such a decrease may signify elimination of tissue hypoxia after transfusion. We also observed changes in the L/P trend in the 13 hours preceding a change in the hemoglobin level. Fluid administration, which is routinely used as a first-line treatment of hypovolemic shock, can cause hemodilution and decreased hemoglobin. When ScvO2 decreases, increase in L/P ratio may precede the ScvO2 trend by 10 or 11 hours. An increase in the L/P ratio is an early warning sign of insufficient tissue oxygenation and should lead to intensive observation of hemoglobin levels, ScvO2 and other hemodynamic parameters. Patients who were treated more rapidly had lower maximal L/P values and a lower degree of tissue ischemia.ConclusionThe L/P ratio is useful to identify tissue ischemia and can estimate the effectiveness of fluid resuscitation. An increase in the L/P ratio is an early warning sign of inadequate tissue oxygenation and should lead to more detailed hemodynamic and laboratory monitoring. This information cannot usually be obtained from global markers.
“…Tissue values may be influenced by the centralization of the circulation or by a stress-induced (i.e., non-ischemic) increase in lactate [35]. The interpretation of lactate values [12] and the L/P ratio [21] may also be guided by using the studies of patients with septic shock. In those studies, the highest tissue lactate values preceded the highest serum lactate values by 4 hours and the L/P ratio decreased in reaction to transfusion.…”
Section: Discussionmentioning
confidence: 99%
“…However, normal serum lactate values do not provide any information about the regional state of tissues. Patients in shock exhibit a difference in the level of lactate between the tissues and the blood [12]. The most important value is the lactate/pyruvate (L/P) ratio in the extracellular fluid, which serves as a timely marker of emerging ischemia and allows for the monitoring of hemorrhagic shock [13,14].…”
BackgroundTraumatic hemorrhagic shock resulting in tissue hypoxia is a significant cause of morbidity and mortality in polytraumatized patients. Early identification of tissue hypoxia is possible with microdialysis. The aim of this study was to determine the correlation between a marker of tissue hypoxia (L/P; lactate to pyruvate ratio) and selected parameters of systemic oxygen delivery (Hb; hemoglobin) and oxygen extraction (ScvO2; central venous oxygen saturation). We also investigated the severity of tissue hypoxia over the course of care.MethodsAdult patients with traumatic hemorrhagic shock were enrolled in this prospective, observational study. Microdialysis of the peripheral muscle tissue was performed. Demographic data and timeline of care were collected. Tissue lactate, pyruvate, glycerol, glucose levels, hemoglobin, serum lactate and oxygen saturation of the central venous blood (ScvO2) levels were also measured.ResultsThe L/P ratio trend may react to changes in systemic hemoglobin levels with a delay of 7 to 10 hours, particularly when systemic hemoglobin levels are increased by transfusion. Decrease in tissue L/P ratio may react to increase in ScvO2 with a delay of up to 10 hours, and such a decrease may signify elimination of tissue hypoxia after transfusion. We also observed changes in the L/P trend in the 13 hours preceding a change in the hemoglobin level. Fluid administration, which is routinely used as a first-line treatment of hypovolemic shock, can cause hemodilution and decreased hemoglobin. When ScvO2 decreases, increase in L/P ratio may precede the ScvO2 trend by 10 or 11 hours. An increase in the L/P ratio is an early warning sign of insufficient tissue oxygenation and should lead to intensive observation of hemoglobin levels, ScvO2 and other hemodynamic parameters. Patients who were treated more rapidly had lower maximal L/P values and a lower degree of tissue ischemia.ConclusionThe L/P ratio is useful to identify tissue ischemia and can estimate the effectiveness of fluid resuscitation. An increase in the L/P ratio is an early warning sign of inadequate tissue oxygenation and should lead to more detailed hemodynamic and laboratory monitoring. This information cannot usually be obtained from global markers.
“…Indeed, monitoring of the interstitium is feasible with the implementation of minimally invasive techniques, including microdialysis (MD) [ 15 , 16 , 17 , 18 ]. MD is now increasingly used in critically ill septic patients as a research tool and the measurement of metabolites, such as lactate, pyruvate and glycerol together with the calculation of the lactate/pyruvate (L/P) ratio, directly assess energy metabolic disorders at the tissue level [ 18 , 19 , 20 , 21 , 22 , 23 , 24 , 25 , 26 , 27 , 28 , 29 , 30 ]. In this regard, a recent study by our group examined the interplay between adipose tissue and blood lactate and found that in ICU patients with septic or cardiogenic shock the rise in tissue lactate preceded the increase in blood lactate [ 19 ].…”
No study has directly measured tissue lactate clearance in patients with sepsis during the post-resuscitation period. In this study we aimed to assess in ICU patients with sepsis (n = 32) or septic shock (n = 79)—during the post-resuscitation phase—the relative kinetics of blood/tissue lactate clearances and to examine whether these are associated with outcome. We measured serially—over a 48-h period—blood and adipose tissue interstitial fluid lactate levels (with microdialysis) and we calculated lactate clearance. Statistics included mixed model analysis, Friedman’s analysis of variance, Wilcoxon’s test, Mann-Whitney’s test, receiver operating characteristics curves and logistic regression. Forty patients died (28-day mortality rate = 28%). Tissue lactate clearance was higher compared to blood lactate clearance at 0–8, 0–12, 0–16, 0–20 and 0–24 h (all p < 0.05). Tissue lactate clearance was higher in survivors compared to non-survivors at 0–12, 0–20 and 0–24 h (all p = 0.02). APACHE II along with tissue lactate clearance <30% at 0–12, 0–20 and 0–24 h were independent outcome predictors. We did not find blood lactate clearance to be related to survival. Thus, in critically ill septic patients, elevated tissue (but not blood) lactate clearance, was associated with a favorable clinical outcome.
“…Metabolic tissue monitoring is possible using the technique of microdialysis, which allows for organ-specific metabolic monitoring based on interstitial fluid samples [33]. Microdialysis proved to be a sensitive method for the early detection of metabolic changes in various organs during endotoxemia, even before systemic effects occur [1,[15][16][17]20,23,24,26]. Previous work using in vivo microdialysis in experimental endotoxin shock demonstrated the protective effects of endotoxin preconditioning with MPL on tissue metabolism -i.e.…”
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