Central Venous-to-arterial Carbon Dioxide Difference/ Arterial-central Venous Oxygen Content Ration Monitor Oxygen Metabolism And Evaluate Of Oxygen Consumption In Fluid Resuscitation

Part Ⅰthe correlation between Central venous-to-arterial carbon dioxide Difference/ Arterial-central venous oxygen content ration and lactate in patients with sepsisObjective:To assess the correlation between Central venous-to-arterial carbon dioxide Difference/Arterial-central venous oxygen content ration and arterial lactate in patients with sepsis. Method: A collection of clinical data of 36 patients with sepsis admitted to the Intensive Care Unit(ICU) of Nanjng Drum Tower Hospital affiliated to Medical School of Nanjing University from May 1st 2013 to November 1st 2013 was made. Retrospective analysis of arterial lactate and corresponding P(cv-a)CO2/C(a-cv)O2、central venous to arterial carbon dioxide difference(Pcv-aCO2)、central venous oxygen saturation(ScvO2)、oxygen delivery(DO2) and oxygen consumption(V02). A total of 119 groups of data was collected. The data were divided into groups of hyperlactatemia(≥2mmol/l) and normal lactate(<2mmol/l) according to arterial lactate levels. Compared P(cv-a)CO2/C(a-cv)O2 and other oxygen metabolism parameters between the two groups. Using receiver operating characteristic curve (ROC) to compared the ability of P(cv-a)CO2/C(a-cv)O2 and other parameters to diagnose hyperlactatemia. Results:P(cv-a)CO2/C(a-cv)O2 level was higher in hyperlactatemia group, has significant difference(1.38±0.76 mmHg/ml VS 2.31±1.01 mmHg/ml,p<0.05). ScvO2、DO2、VO2 were lower in hyperlactatemia group(74.26±9.13% VS 70.29±9.72%;505.52±208.39 ml/min.m2 VS 429.98±173.63 ml/min.m2;129.01±54.94 ml/min.m2 VS 109.99±38.79 ml/min.m2, p<0.05). Pcv-aCO2 has no significant difference between the two groups(5.76±3.70mmHg VS 6.59±3.70 mmHg,p>0.05). P(cv-a)CO2/C(a-cv)O2 was positively correlated with lactate(r= 0.646, p<0.05). Compared the area under ROC curve(AUC), the ability of P(cv-a)CO2/C(a-cv)O2 to diagnose hyperlactatemia was strongest(0.820, p<0.001). P(cv-a)CO2/C(a-cv)O2≥1.575mmHg/ml diangose hyperlactatemia with sensitivity 83.3% and specificity 73.5%. AUC for ScvO2 was 0.622,p=0.025. Conclusions: Compared with the traditional oxygen metabolism parameters, P(cv-a)CO2/C(a-cv)O2 can accurately diangose hyperlactatemia, and is a reliable parameter to reflect oxygen metabolism in patients with sepsis.PartⅡCentral venous-to-arterial carbon dioxide Difference/Arterial-central venous oxygen content ration evaluate of oxygen consumption in fluid resuscitationObjective:To evaluate of Central venous-to-arterial carbon dioxide Difference/Arterial-central venous oxygen content ration in change of oxygen consumption in fluid resuscitation. Method:Use prospective study method,18 patients with septic shock admitted to the Intensive Care Unit(ICU) of Nanjng Drum Tower Hospital affiliated to Medical School of Nanjing University from November 1st 2013 to april 1st 2014 were enrolled in the study. Monitoring of P(cv-a)CO2/C(a-cv)O2、arterial lactate and ScvO2. Cardiac output index (CI) were determined by Pulse indicator continuous cardiac output (PICCO). By arterial and central oxygen blood gas analysis, oxygen consumption(VO2) is calculated. All patients were given fluid challenge (300ml saline for 20 min, rapid intravenous infusion). All patients were divided into fluid responded group(Δ CI≥10%) and fluid unresponded group(ΔCI<10%), according to the change of CI(ΔCI) after fluid challenge. Compared P(cv-a)CO2/C(a-cv)O2、arterial lactate、ScvO2 and other hemodynamic parameters before fluid challenge between the two groups. Then the patients were divided into two subgroups in responded group, namely Δ VO2≥10% group and ΔVO2<10% group, according to the change of VO2(ΔVO2). Compared P(cv-a)CO2/C(a-cv)O2、arterial lactate、ScvO2 and other hemodynamic parameters before fluid challenge between the two subgroups. Results:(1)Fluid challenges were performed 23 instances in 18 patients, among which 17 instances were defined as response group. P(cv-a)CO2/C(a-cv)O2 was significant decrease in fluid responded group after resuscitation(2.05±0.75 mmHg/ml VS 1.43±0.60 mmHg/ml,p<0.05). Lactate is also decrease in fluid responded group after resuscitation (3.78±2.50mmol/l VS 2.34±1.82 mmol/l,p<0.05). CVP、CI、SI、DO2、VO2 were significant increase after resuscitation(8.92±3.94mmHg VS 10.67±4.44mmHg;3.23±1.73 1/min.m2 VS 3.99 ±1.73 1/min.m2;30.54 ± 10.37 ml/m2 VS 35.73 ± 11.41 ml/m2;454.00 ± 278.41ml/min.m2 VS 547.07±298.83 ml/min.m2;101.58±46.53 ml/min.m2 VS 118.92±55.23 ml/min.m2,p<0.05). ScvO2 has no significant change after resuscitation(73.71±9.64% VS 75.37±9.69%,p>0.05). (2) Compared fluid responded group and fluid unresponded group, P(cv-a)CO2/C(a-cv)O2、arterial lactate and ScvO2 before resuscitation have no significant difference(2.05±0.75 mmHg/ml VS 1.58±0.67 mmHg/ml;3.78±2.50 mmol/1 VS 3.26±2.42mmol/l;73.71± 9.64% VS 70.30±12.01%, p>0.05). (3) In fluid response group, there were 10 instances in Δ VO2≥10% group and 7 instances in Δ VO2<10% group. P(cv-a)CO2/C(a-cv)O2 was significant highter in Δ VO2≥10% group before resuscitation, when compared Δ VO2<10% group(2.43±0.73 mmHg/ml VS 1.51± 0.37 mmHg/ml,p<0.05). Lactate is also highter in Δ VO22≥10% group before resuscitation (4.53±2.52 mmol/1 VS 1.46±0.82 mmol/l,p<0.05). ScvO2 has no significant difference between the two groups(70.79±9.15% VS 72.13±13.42%,p> 0.05). (4) AUC for P(cv-a)CO2/C(a-cv)O2、lactate and ScvO2 were 0.843、0.921 and 0.529. P(cv-a)CO2/C(a-cv)O2≥1.885mmHg/ml predictedΔ VO2≥10% after fluid resuscitation with sensitivity 70% and specificity 86%. Conclusions:For septic shock patients with fluid responsiveness, P(cv-a)CO2/C(a-cv)O2 can evaluate of increase in oxygen consumption after fluid resuscitation and can be used as an reliable parameter to guide fluid resuscitation.