scholarly journals Monitoring Microcirculatory Blood Flow with a New Sublingual Tonometer in a Porcine Model of Hemorrhagic Shock

2015 ◽  
Vol 2015 ◽  
pp. 1-10 ◽  
Author(s):  
Péter Palágyi ◽  
József Kaszaki ◽  
Andrea Rostás ◽  
Dániel Érces ◽  
Márton Németh ◽  
...  
Keyword(s):  
Hemorrhagic Shock ◽  
Central Venous Oxygen Saturation ◽  
Carbon Dioxide Partial Pressure ◽  
Orthogonal Polarization ◽  
Rubber Tube ◽  
Capillary Perfusion ◽  
Central Venous ◽  
Significant Drop ◽  
Orthogonal Polarization Spectral ◽  
Indirect Evaluation

Tissue capnometry may be suitable for the indirect evaluation of regional hypoperfusion. We tested the performance of a new sublingual capillary tonometer in experimental hemorrhage. Thirty-six anesthetized, ventilated mini pigs were divided into sham-operated (n=9) and shock groups (n=27). Hemorrhagic shock was induced by reducing mean arterial pressure (MAP) to 40 mmHg for 60 min, after which fluid resuscitation started aiming to increase MAP to 75% of the baseline value (60–180 min). Sublingual carbon-dioxide partial pressure was measured by tonometry, using a specially coiled silicone rubber tube. Mucosal red blood cell velocity (RBCV) and capillary perfusion rate (CPR) were assessed by orthogonal polarization spectral (OPS) imaging. In the 60 min shock phase a significant drop in cardiac index was accompanied by reduction in sublingual RBCV and CPR and significant increase in the sublingual mucosal-to-arterial PCO2gap (PSLCO2gap), which significantly improved during the 120 min resuscitation phase. There was significant correlation betweenPSLCO2gap and sublingual RBCV (r=-0.65,p<0.0001), CPR (r=-0.64,p<0.0001), central venous oxygen saturation (r=-0.50,p<0.0001), and central venous-to-arterial PCO2difference (r=0.62,p<0.0001). This new sublingual tonometer may be an appropriate tool for the indirect evaluation of circulatory changes in shock.

scholarly journals Central Venous-to-ArterialCO2Gap Is a Useful Parameter in Monitoring Hypovolemia-Caused Altered Oxygen Balance: Animal Study

2013 ◽  
Vol 2013 ◽  
pp. 1-7 ◽  
Author(s):  
Szilvia Kocsi ◽  
Gabor Demeter ◽  
Daniel Erces ◽  
Eniko Nagy ◽  
Jozsef Kaszaki ◽  
...  
Keyword(s):  
Central Venous Oxygen Saturation ◽  
Blood Gas Analysis ◽  
Significant Negative Correlation ◽  
Gas Analysis ◽  
Oxygen Extraction ◽  
Oxygen Balance ◽  
Capillary Perfusion ◽  
Central Venous ◽  
Significant Drop ◽  
Red Blood Cell Velocity

Monitoring hypovolemia is an everyday challenge in critical care, with no consensus on the best indicator or what is the clinically relevant level of hypovolemia. The aim of this experiment was to determine how central venous oxygen saturation (ScvO2) and central venous-to-arterial carbon dioxide difference (CO2gap) reflect hypovolemia-caused changes in the balance of oxygen delivery and consumption. Anesthetized, ventilated Vietnamese minipigs (n=10) were given a bolus followed by a continuous infusion of furosemide. At baseline and then in five stages hemodynamic, microcirculatory measurements and blood gas analysis were performed. Oxygen extraction increased significantly, which was accompanied by a significant drop in ScvO2and a significant increase in CO2gap. There was a significant negative correlation between oxygen extraction and ScvO2and significant positive correlation between oxygen extraction and CO2gap. TakingScvO2<73% and CO2gap >6 mmHg values together to predict an oxygen extraction >30%, the positive predictive value is 100%; negative predicted value is 72%. Microcirculatory parameters, capillary perfusion rate and red blood cell velocity, decreased significantly over time. Similar changes were not observed in the sham group. Our data suggest thatScvO2<73% and CO2gap >6 mmHg can be complementary tools in detecting hypovolemia-caused imbalance of oxygen extraction.

Abstract P29: Impaired Systemic but Preserved Cerebral Microcirculation Following Hemorrhagic Shock and Fluid Resuscitation

Circulation ◽  
2008 ◽  
Vol 118 (suppl_18) ◽  
Author(s):  
Zhi Wan ◽  
Shijie Sun ◽  
Giuseppe Ristagno ◽  
Yongqin Li ◽  
Max H Weil ◽  
...  
Keyword(s):  
Arterial Pressure ◽  
Hemorrhagic Shock ◽  
Orthogonal Polarization ◽  
Cerebral Microcirculation ◽  
Sprague Dawley ◽  
Fluid Infusion ◽  
Descending Aorta ◽  
Shed Blood ◽  
Sprague Dawley Rats ◽  
Orthogonal Polarization Spectral

Background: Decreases in buccal microcirculation are associated with severity and outcomes of circulatory shock. However, there is evidence that cerebral function is unimpaired after even severe states of hemorrhagic shock. We therefore hypothesized that in severe states of hemorrhagic shock with profound decreases in buccal microcirculation, the cerebral microcirculation may be preserved. Method: Craniotomies were performed in 15 male Sprague-Dawley rats, weighing 450–550g, to expose the parietal cortex for visualization of microcirculation. Animals were then bled via a catheter advanced into the descending aorta. An estimated 35% or 25% of blood volume was bled over 60 minutes and measurements were compared with unbled control. Sixty minutes after onset of hypotension, bled animals received normal saline infused over 30 minutes in amounts equivalent to two times the volume of shed blood. Cerebral and buccal microcirculations were visualized with orthogonal polarization spectral imaging. Result: Reductions in mean arterial pressure (MAP) were partially reversed after fluid infusion (Figure 1 ). Buccal microcirculation was restored to baseline level after the 25% blood loss and partially restored after the 35% loss. The cerebral microcirculation, however, was unchanged during both hemorrhagic hypotension and following volume repletion. Conclusion: In contrast to the striking reduction in arterial pressure and systemic microcirculation, the cerebral microcirculatory blood flow was preserved during hemorrhagic shock of moderate and severe degrees. These findings confirm a dissociation between the macrocirculation and the cerebral microcirculation.

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