ObjectiveTo explore the influence of norepinephrine on the prediction of fluid responsiveness by passive leg raising (PLR) during septic shock. MethodsForty-six septic shock patients in intensive care unit of Nanjing Drum Tower Hospital were prospectively observed from September to November 2012. Among which 36 septic shock patients were enrolled with a positive PLR test (defined by an increase in stroke volume index ≥10%). A PLR test was performed at baseline (PLR1). A second PLR test (PLR2) was performed at returning to supine position for 10 min and the dose of norepinephrine was increased to maintain MAP ≥65 mmHg for 20 min. The changes of heart rate(HR),mean arterial pressure(MAP),central venous pressure(CVP),cardiac index(CI),stroke volume index(SVI),index of systemic vascular resistance(SVRI),global end-diastolic volume index(GEDVI),and cardiac function index(CFI) were monitored by transpulmonary thermodilution technique (PiCCO). ResultsPLR1 significantly increased SVI by (20.54±9.63)%,CI by (20.57±9.89)%,MAP by (7.64±5.77)%,and CVP by (25.83±23.39)%. As the dose of norepinephrine increased,SVI was increased by (16.97±9.06)%,CI by (16.78±8.39)%,GEDVI by (9.08±4.47)%,MAP by (28.07±12.48)%,and CVP by (7.86±8.52)%. PLR2 increased SVI by (13.74±8.79)%,CI by (13.79±9.08)%,MAP by (2.93±5.06)%,and CVP by (13.36±14.74)%. The PLR2 and the dose increase of norepinephrine augmented SVI to a significantly lesser extent than the PLR1 performed at baseline (both P<0.05). However,SVI increased by <10% in 6 patients while the baseline PLR was positive in these patients. ConclusionIn septic patients with a positive PLR at baseline,norepinephrine increases cardiac preload and cardiac output and influences the fluid responsiveness.
ObjectiveTo evaluate the value of stroke volume variation (SVV) and intrathoracic blood volume index (ITBVI) to predict fluid responsiveness in mechanically ventilated septic shock patients with spontaneous breathing. MethodsA prospective observational study was conducted in the Department of Critical Care Medicine of the First Affiliated Hospital of Guangzhou Medical University. Fluid resuscitation data was collected in septic shock patients who received PiCCO monitoring from June 2013 to June 2014. Transpulmonary thermodilution data were collected before and after fluid resuscitation, including cardiac index (CI), SVV, ITBVI, and central venous pressure (CVP). Seventeen patients were defined as responders by an observed increase of≥15% in the cardiac index (CI) after fluid resuscitation, 12 patients were defined as non-responders. Pearson correlation between changes of CI (ΔCI) and SVV, ITBVI, CVP was established. Area under the receiver operating characteristic (ROC) curve of SVV, ITBVI and CVP was calculated for predicting fluid responsiveness. ResultsBaseline CI and ITBVI were significantly lower in the responders (P < 0.05).There was no significant difference in baseline SVV between the responders and the non-responders (P > 0.05). A significant correlation was found between baseline ITBVI andΔCI (r=-0.593, P < 0.001), but no significant correlation between SVV andΔCI (r=0.037, P=0.847) or CVP andΔCI (r=0.198, P=0.302). The area under ROC curve of SVV, ITBVI and SVV for predicting fluid responsiveness was 0.640 (P=0.207), 0.865 (P=0.001), and 0.463 (P=0.565), respectively. The cut-off value of ITBVI for predicting fluid responsiveness was 784 mL/m2 with a sensitivity of 100.0% and a specificity of 70.6%. ConclusionIn mechanically ventilated septic shock patients with spontaneous breathing, ITBVI may be a valuable indicator in predicting fluid responsiveness compared with SVV.
Objective To investigate the value of central venous-to-arterial carbon dioxide difference/arterial-to-venous oxygen difference ratio [P(cv-a)CO2/C(a-cv)O2] in predicting oxygen metabolism after fluid resuscitation in patients with septic shock. Methods A prospective observational study was carried out on septic shock patients admitted in the intensive care unit of Nanjng Drum Tower Hospital from November 2013 to April 2014. All patients underwent fluid challenge (300 ml saline for 20 min, rapid intravenous infusion). The patients were divided into a fluid responded group (ΔCI≥10%) and a fluid unresponded group (ΔCI＜10%), according to the change of cardiac output index (ΔCI) after fluid challenge. Then the patients were divided into two subgroups in the fluid responded group, namely a ΔVO2≥10% group and a ΔVO2＜10% group, according to the change of VO2 (ΔVO2). Cardiac output index (CI) were determined by pulse indicator continuous cardiac output (PICCO). Hemoglobin, arterial carbon dioxide (PaCO2), arterial oxygen (PaO2), arterial oxygen saturation (SaO2), arterial blood lactate, central venous carbon dioxide (PcvCO2), central venous oxygen (PcvO2) and central venous oxygen saturation (ScvO2) were measured by blood gas analysis. P(cv-a)CO2/C(a-cv)O2 and oxygen consumption (VO2) were calculated. P(cv-a)CO2/C(a-cv)O2 before and after fluid challenge was compared between two subgroups. Results Fluid challenges were performed in 23 instances in 18 patients, among which 17 instances were defined as the fluid responded group. Compared with the fluid unresponded group, P(cv-a)CO2/C(a-cv)O2, arterial lactate and ScvO2 had no significant difference [P(cv-a)CO2/C(a-cv)O2](mm Hg/ml): 2.05±0.75vs. 1.58±0.67; arterial lactate (mmol/l): 3.78±2.50vs. 3.26±2.42; ScvO2(%): 73.71±9.64vs. 70.30±12.01,P＞0.05] in the fluid responded group before resuscitation. In the fluid responded group, there were 10 instances in the ΔVO2≥10% group and 7 instances in the ΔVO2＜10% group. P(cv-a)CO2/C(a-cv)O2 (mm Hg/ml) was significantly higher in the ΔVO2≥10% group before resuscitation compared with the ΔVO2＜10% group (2.43±0.73vs. 1.51±0.37,P＜0.01). Lactate (mmol/l) was also higher in the ΔVO2≥10% group before resuscitation (4.53±2.52vs. 1.46±0.82,P＜0.01). ScvO2 (%) had no significant difference between two groups (70.79±9.15vs. 72.13±13.42,P＞0.05). The areas under ROC curve (AUCs) of P(cv-a)CO2/C(a-cv)O2, lactate and ScvO2 for predicting ΔVO2≥10% were 0.843, 0.921, and 0.529, respectively. The sensitivity and specificity of P(cv-a)CO2/C(a-cv)O2≥1.885 mm Hg/ml for predicting ΔVO2≥10% after fluid resuscitation were 70% and 86%, respectively. Conclusion For septic shock patients with fluid responsiveness, P(cv-a)CO2/C(a-cv)O2 can predict oxygen metabolism after fluid resuscitation and can be used as a reliable parameter to guide fluid resuscitation.