Dataset Information

Ratios of central venous-to-arterial carbon dioxide content or tension to arteriovenous oxygen content are better markers of global anaerobic metabolism than lactate in septic shock patients.

ABSTRACT:

Background

To evaluate the ability of the central venous-to-arterial CO2 content and tension differences to arteriovenous oxygen content difference ratios (?ContCO2/?ContO2 and ?PCO2/?ContO2, respectively), blood lactate concentration, and central venous oxygen saturation (ScvO2) to detect the presence of global anaerobic metabolism through the increase in oxygen consumption (VO2) after an acute increase in oxygen supply (DO2) induced by volume expansion (VO2/DO2 dependence).

Methods

We prospectively studied 98 critically ill mechanically ventilated patients in whom a fluid challenge was decided due to acute circulatory failure related to septic shock. Before and after volume expansion (500 mL of colloid solution), we measured cardiac index, VO2, DO2, ?ContCO2/?ContO2 and ?PCO2/?ContO2 ratios, lactate, and ScvO2. Fluid-responders were defined as a ?15 % increase in cardiac index. Areas under the receiver operating characteristic curves (AUC) were determined for these variables.

Results

Fifty-one patients were fluid-responders (52 %). DO2 increased significantly (31 ± 12 %) in these patients. An increase in VO2 ? 15 % ("VO2-responders") concurrently occurred in 57 % of the 51 fluid-responders (45 ± 16 %). Compared with VO2-non-responders, VO2-responders were characterized by higher lactate levels and higher ?ContCO2/?ContO2 and ?PCO2/?ContO2 ratios. At baseline, lactate predicted a fluid-induced increase in VO2 ? 15 % with AUC of 0.745. Baseline ?ContCO2/?ContO2 and ?PCO2/?ContO2 ratios predicted an increase of VO2 ? 15 % with AUCs of 0.965 and 0.962, respectively. Baseline ScvO2 was not able to predict an increase of VO2 ? 15 % (AUC = 0.624).

Conclusions

?ContCO2/?ContO2 and ?PCO2/?ContO2 ratios are more reliable markers of global anaerobic metabolism than lactate. ScvO2 failed to predict the presence of global tissue hypoxia.

SUBMITTER: Mallat J

PROVIDER: S-EPMC4740480 | biostudies-literature | 2016 Dec

REPOSITORIES: biostudies-literature

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Publications

Ratios of central venous-to-arterial carbon dioxide content or tension to arteriovenous oxygen content are better markers of global anaerobic metabolism than lactate in septic shock patients.

Mallat Jihad J Lemyze Malcolm M Meddour Mehdi M Pepy Florent F Gasan Gaelle G Barrailler Stephanie S Durville Emmanuelle E Temime Johanna J Vangrunderbeeck Nicolas N Tronchon Laurent L Vallet Benoît B Thevenin Didier D

Annals of intensive care 20160203 1

<h4>Background</h4>To evaluate the ability of the central venous-to-arterial CO2 content and tension differences to arteriovenous oxygen content difference ratios (∆ContCO2/∆ContO2 and ∆PCO2/∆ContO2, respectively), blood lactate concentration, and central venous oxygen saturation (ScvO2) to detect the presence of global anaerobic metabolism through the increase in oxygen consumption (VO2) after an acute increase in oxygen supply (DO2) induced by volume expansion (VO2/DO2 dependence).<h4>Methods< ...[more]

PMID: 26842697

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Project description:BackgroundThe optimal timing of lactate measurement for septic patients in the intensive care unit (ICU) remains controversial, and whether initiating and repeating the lactate measurement earlier could make a difference for septic patients with an elevated lactate level remains unexplored.MethodsThis was a retrospective observational study that included septic patients with an initial lactate level > 2.0 mmol/L after ICU admission, and all data were extracted from the Medical Information Mart for Intensive Care III (MIMIC-III) database. The main exposure of interest was the early lactate measurement, which was defined as an initial lactate level measurement within 1 h after ICU admission. The primary outcome was 28-day mortality.ResultsA total of 2642 eligible subjects were enrolled, including 738 patients who had initial lactate measurements completed within 1 h (EL group) and 1904 patients who had initial lactate measurements completed more than 1 h after ICU admission (LL group). A significant beneficial effect of early lactate measurement in terms of 28-day mortality was observed: the adjusted odds ratio (OR) was 0.69 (95% CI 0.55-0.87; p = 0.001), and the mediation effect of the time to initial vasopressor administration was significant (average causal mediation effect (ACME) - 0.018; 95% CI - 0.005 approximately to - 0.036; p < 0.001). A strong relationship between delayed initial lactate measurement and risk-adjusted 28-day mortality was noted (OR 1.04; 95% CI 1.02-1.05; p < 0.001). Each hour of delay in remeasuring the lactate level was associated with an increase in 28-day mortality in the EL group (OR 1.09; 95% CI 1.04-1.15; p < 0.001). Further analysis demonstrated that repeating the measurement 3 h after the initial lactate measurement led to a significant difference.ConclusionsEarly lactate measurement is associated with a lower risk-adjusted 28-day mortality rate in septic patients with lactate levels > 2.0 mmol/L. A shorter time to the initial vasopressor administration may contribute to this relationship. Repeating the lactate measurement within 3 h after the initial measurement is appropriate for patients whose lactate levels were measured within 1 h of admission.

Project description:IntroductionVenous-to-arterial carbon dioxide difference (Pv-aCO2) may reflect the adequacy of blood flow during shock states. We sought to test whether the development of Pv-aCO2 during the very early phases of resuscitation is related to multi-organ dysfunction and outcomes in a population of septic shock patients resuscitated targeting the usual oxygen-derived and hemodynamic parameters.MethodsWe conducted a prospective observational study in a 60-bed mixed ICU in a University affiliated Hospital. 85 patients with a new septic shock episode were included. A Pv-aCO2 value ? 6 mmHg was considered to be high. Patients were classified in four predefined groups according to the Pv-aCO2 evolution during the first 6 hours of resuscitation: (1) persistently high Pv-aCO2 (high at T0 and T6); (2) increasing Pv-aCO2 (normal at T0, high at T6); (3) decreasing Pv-aCO2 (high at T0, normal at T6); and (4) persistently normal Pv-aCO2 (normal at T0 and T6). Multiorgan dysfunction at day-3 was compared for predefined groups and a Kaplan Meier curve was constructed to show the survival probabilities at day-28 using a log-rank test to evaluate differences between groups. A Spearman-Rho was used to test the agreement between cardiac output and Pv-aCO2. Finally, we calculated the mortality risk ratios at day-28 among patients attaining normal oxygen parameters but with a concomitantly increased Pv-aCO2.ResultsPatients with persistently high and increasing Pv-aCO2 at T6 had significant higher SOFA scores at day-3 (p < 0.001) and higher mortality rates at day-28 (log rank test: 19.21, p < 0.001) compared with patients who evolved with normal Pv-aCO2 at T6. Interestingly, a poor agreement between cardiac output and Pv-aCO2 was observed (r2 = 0.025, p < 0.01) at different points of resuscitation. Patients who reached a central venous saturation (ScvO)2 ? 70% or mixed venous oxygen saturation (SvO2) ? 65% but with concomitantly high Pv-aCO2 at different developmental points (i.e., T0, T6 and T12) had a significant mortality risk ratio at day-28.ConclusionThe persistence of high Pv-aCO2 during the early resuscitation of septic shock was associated with more severe multi-organ dysfunction and worse outcomes at day-28. Although mechanisms conducting to increase Pv-aCO2 during septic shock are insufficiently understood, Pv-aCO2 could identify a high risk of death in apparently resuscitated patients.

Project description:The purpose of the study was to evaluate the behavior of the venous-to-arterial CO2 tension difference (ΔPCO2) over the arterial-to-venous oxygen content difference (ΔO2) ratio (ΔPCO2/ΔO2) and the difference between venous-to-arterial CO2 content calculated with the Douglas' equation (ΔCCO2D) over ΔO2 ratio (ΔCCO2D/ΔO2) and their abilities to reflect the occurrence of anaerobic metabolism in two experimental models of tissue hypoxia: ischemic hypoxia (IH) and hypoxic hypoxia (HH). We also aimed to assess the influence of metabolic acidosis and Haldane effects on the PCO2/CO2 content relationship. In a vascularly isolated, innervated dog hindlimb perfused with a pump-membrane oxygenator system, the oxygen delivery (DO2) was lowered in a stepwise manner to decrease it beyond critical DO2 (DO2crit) by lowering either arterial PO2 (HH-model) or flow (IH-model). Twelve anesthetized and mechanically ventilated dogs were studied, 6 in each model. Limb DO2, oxygen consumption ([Formula: see text]), ΔPCO2/ΔO2, and ΔCCO2D/ΔO2 were obtained every 15 min. Beyond DO2crit, [Formula: see text] decreased, indicating dysoxia. ΔPCO2/ΔO2, and ΔCCO2D/ΔO2 increased significantly only after reaching DO2crit in both models. At DO2crit, ΔPCO2/ΔO2 was significantly higher in the HH-model than in the IH-model (1.82 ± 0.09 vs. 1.39 ± 0.06, p = 0.002). At DO2crit, ΔCCO2D/ΔO2 was not significantly different between the two groups (0.87 ± 0.05 for IH vs. 1.01 ± 0.06 for HH, p = 0.09). Below DO2crit, we observed a discrepancy between the behavior of the two indices. In both models, ΔPCO2/ΔO2 continued to increase significantly (higher in the HH-model), whereas ΔCCO2D/ΔO2 tended to decrease to become not significantly different from its baseline in the IH-model. Metabolic acidosis significantly influenced the PCO2/CO2 content relationship, but not the Haldane effect. ΔPCO2/ΔO2 was able to depict the occurrence of anaerobic metabolism in both tissue hypoxia models. However, at very low DO2 values, ΔPCO2/ΔO2 did not only reflect the ongoing anaerobic metabolism; it was confounded by the effects of metabolic acidosis on the CO2-hemoglobin dissociation curve, and then it should be interpreted with caution.

Dataset Information

Ratios of central venous-to-arterial carbon dioxide content or tension to arteriovenous oxygen content are better markers of global anaerobic metabolism than lactate in septic shock patients.

Background

Methods

Results

Conclusions

Publications

Ratios of central venous-to-arterial carbon dioxide content or tension to arteriovenous oxygen content are better markers of global anaerobic metabolism than lactate in septic shock patients.

Similar Datasets

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