| Objective l.To investigate the correlation between oxygen challenge test (OCT) and ScvO2in septic shock patients.2. To investigate changes in global hemodynamics, oxygen metabolism and PtO2during30min pure oxygen ventilation in endotoxin induced septic rabbit mode, and explore the value of OCT for revealing the global and local oxygen metabolism.Methods1. Clinical research section:49septic shock patients were prospectively studied, who underwent PtO2monitoring and OCT (1.0FiO2for10min). Baseline central venous blood gases and baseline arterial blood gases were examined, as well as post-OCT arterial blood gases. We calculated PtO2I (baseline PtO2/PaO2),10min OCT [(PtO2after10min on FiO2of1.0)-(baseline PtO2)], OCI [(10minOCT)/(PaO2on FiO21.0-baseline PaO2)] during OCT. Patients were divided into two groups according to ScvO2values:normal ScvO2group (ScvO2≥70%) versus low ScvO2group (ScvO2<70%).2. Experimental study section:6septic shock rabbits were study. They all received mechanical ventilation, and were placed central venous, PiCCO-Plus catheters. A30-min period of OCT (pure oxygen ventilation) underwent at the early and late stage of shock following injected the endotoxin. Before and at30-min of pure oxygen ventilation, we simultaneously measured global hemodynamic variables, arterial and central venous blood gas, PtO2.Results:1.clincal research section (1) There was a significant correlation between baseline PtO2(r=0.382, P=0.007),10minOCT (r=0.427, P=0.002), OCI (r=0.5, P<0.001) and ScvO2;(2) There were27patients in the low ScvO2group, and22patients in the normal ScvO2group. ScvO2was significantly lower in low ScvO2group than in normal ScvO2group (61±8vs.77±6, P<0.05). No differences in age, severity score, vital sign, arterial blood lactate concentration, pressor drugs, PtO2and PtO2I were observed between groups. Compared with patients in normal ScvO2group, patients in low ScvO2group had lower10minOCT and OCI (P<0.05);(3) The area under the receiver operating characteristic curve (ROC) for detecting lower ScvO2values was0.621,0.56,0.721and0.763, respectively, according to baseline PtO2, PtO2I,10minOCT and OCI. The cutoff of 10minOCT was≤57mmHg, for detecting ScvO2values lower than70%, resulting in a sensitivity of51.9%and a specificity of95.5%2.experimental study section (1) The pure oxygen ventilation (30-min for1.0FiO2) significantly increased PaO2(184±74vs.532±123mmHg, P=0.000).(2).The pure oxygen ventilation did not significantly affect heart rate and MAP, however slightly increases SVRI and decreases CI.(3) Without significantly change in VO2I, pure oxygen ventilation increased ScvO2and increased DO2I, even in the late stage of shock when ScvO2<70%.(5) In the OCT, there was a significant positive correlation between30minOCT (r=0.923, P=0.001), OCI (r=0.902, P=0.001) and ScvO2, but not with baseline PtO2and baseline PtO2I.(4).No differences in PaO2change, baseline PtO2and baseline PtO2l were observed between the early and late stage of shock. Compared with the early stage,30minOCT and OCI is lower in the late shock stage during pure oxygen challenge test.Conclusion Oxygen challenge test could improve the diagnostic accuracy of the PtO2in assessing low ScvO2values in septic shock patients after resuscitation; We propose that the pure oxygen challenge test as an alternative method of PtO2for revealing tissue perfusion in septic shock. Objective To investigate the correlation between oxygen challenge test [the degree of PtO2response to increased fractional inspired oxygen concentration (FiO2) of1.0is identified as the transcutaneous Oxygen Challenge test, OCT] and central venous oxygen saturation(ScvO2) in septic shock patients after resuscitation.Methods49septic shock patients were prospectively studied, who underwent PtO2 monitoring and OCT (temporary increase of FiO2for10min). Baseline central venous blood gases and baseline arterial blood gases were examined, as well as post-OCT arterial blood gases. We calculated PtO2I(baseline PtO2/PaO2), lOminOCT [(PtO2after10min on FiO2of1.0) minus (baseline PtO2)]、OCI [(10minOCT)/(PaO2on FiO21.0minus baseline PaO2)] during OCT. Patients were divided into two groups according to ScvO2values: normal ScvO2group (ScvO2≥70%) versus low ScvO2group (ScvO2<70%). The parameters-related of oxygen challenge test between the two groups were compared.Results:(1) There was a significant correlation between baseline PtO2(r=0.382, P=0.007),10minOCT (r=0.427, P=0.002), OCI (r=0.5, P<0.001) and ScvO2, but not with arterial blood lactate concentration;(2) There were27patients in the low ScvO2group, and22patients in the normal ScvO2group. ScvO2was significantly lower in low ScvO2group than in normal ScvO2group (61±8vs.77±6, P<0.05). No differences in age, severity score, vital sign, arterial blood lactate concentration, pressor drugs, PtO2and PtO2I were observed between groups. Compared with patients in normal ScvO2group, patients in low ScvO2group had lower10min OCT value and oxygen challenge index(P<0.05);(3) The area under the receiver operating characteristic curve (ROC) for detecting lower ScvO2values was0.621,0.56,0.721and0.763, respectively, according to baseline PtO2, PtO2I,10mi OCT and OCI. The cutoff of10minOCT was≤57mmHg(1mmHg=0.133kPa) for detecting ScvO2values lower than70%, resulting in a sensitivity of51.9%and a specificity of95.5%.Conclusion Oxygen challenge test could improve the diagnostic accuracy of the PtO2in assessing low ScvO2values in septic shock patients after resuscitation. Objective To investigated changes in global hemodynamics, oxygen metabolism and skin tissue oxygenation during30min pure oxygen ventilation in endotoxin induced septic rabbit mode; and explore the significance of oxygen challenge test in the septic shock.Methods6septic shock rabbits were study. They all received mechanical ventilation, and were placed central venous, PiCCO-Plus catheters. A30-min period of pure oxygen ventilation (1.0FiO2) underwent at the early and late stage of shock following injected the endotoxin. Before and at30-min of pure oxygen ventilation, we simultaneously recorded and measured global hemodynamic variables, arterial and central venous blood gas, transcutaneous oxygen tensions(PtO2).Results (1) The pure oxygen ventilation (30-min for1.0FiO2) significantly increased PaO2(184±74vs.532±123mmHg, P=0.000).(2).The pure oxygen ventilation did not significantly affect heart rate and MAP, however slightly increases SVRI and decreases cardiac index.(3) Without significantly change in VO2I, pure oxygen ventilation increased ScvO2and increased DO2I, even in the late stage of shock when ScvO2<70%.(5) In the pure oxygen challenge test, there was a significant positive correlation between30minOCT (r=0.923, P=0.001), OCI (r=0.902, P=0.001) and ScvO2, but not with baseline PtO2and baseline PtO2index.(4).No differences in PaO2change, baseline PtO2and baseline PtO2index were observed between the early and late stage of shock. Compared with the early stage,30minOCT and Oxygen Challenge index is lower in the late stage during oxygen challenge test.Conclusions:We propose that the oxygen challenge test as an alternative method of PtO2for revealing tissue perfusion in septic shock. |
PDF Full Text Request