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Metabolic effects of volume-oriented therapy for hemorrhagic shock objectified via microdialysis in an animal model
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Veröffentlicht: | 28. April 2011 |
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Objective: During hemorrhagic shock, a qualitative and quantitative reduction in nutritive perfusion of important organs occurs, which leads to hypoxic and metabolic disturbances in cell function. The goal of the study was to objectify the metabolic effects of hemorrhagic shock and volume-oriented therapy on certain organ systems (cerebral, intramuscular) via microdialysis in an animal model.
Methods: A total of 21 pigs (German mixed-breed; 35 ± 9 kg body weight) were included in the study. After a steady state phase of 30 minutes, hemorrhagic shock was initiated in all animals by draining blood within 5 minutes. The target was a MAP of 30 mmHg. After 1 hour of shock, therapy (target: MAP of 60 mmHg) was initiated with crystalloid (Ringer’s solution, n=7) or colloid (Voluven®, n=7) volume replacement. The control group (n=7) received no therapy. Hemodynamic parameters (MAP, HF, CCO) were measured every 15 minutes throughout the observation period (total: 4 hours); blood gas analyses were also performed at these intervals. Microdialysis catheters (CMA 60 and CMA 70) were implanted in brain tissue and intramuscularly in order to determine the interstitial concentrations of the following metabolites: lactate, pyruvate, glycerol, glutamate and glucose. In addition, ICP/CPP and ptiO2 levels were measured in brain tissue.
Results: With respect to the hemodynamic parameters, both therapy groups had significant differences compared to the control group, but not compared to each other. With Voluven® therapy, a significant increase in SvO2 could be achieved. Intramuscular concentrations of lactate, glycerol and glutamate were significantly lower in both therapy groups compared to the control group and the glucose concentrations were higher, whereby the difference between the Voluven® and Ringer’s solution groups was marginal. The concentration differences for glutamate and glycerol and the L/P ratio were significantly higher, to the disadvantage of the Ringer’s solution group. CPP and ptiO2 values were significantly higher in the Voluven® group.
Conclusions: With the help of microdialysis, it is possible to objectify metabolic changes in different tissues at a very early point of time. Voluven® is significantly more suitable as volume replacement than Ringer’s solution in the therapy of hemorrhagic shock. Cerebral microdialysis, as part of multimodal neuromonitoring, is useful to monitor the potential benefit of therapy strategies implemented in critically ill intensive care patients.