Abstract 64: Establishing Microdialysis for Combined Cerebral and Peripheral Monitoring of Cell Metabolism in a Cardiac Arrest Setting in Rats
Introduction: Commonly effects of resuscitative measures are monitored by peripheral functions like ECG or blood pressure (BP). However, it is unknown if these effects will transfer to the brain, the ultimate target of resuscitation. Therefore we set out to establish a model allowing for concomitant determination of cerebral and peripheral metabolism in a complex cardiac arrest setting in rodents.
Methods: In vitro experiments were performed to determine the most reliable flow rate of microdialysis in order to balance temporal resolution and recovery of measures of ischemia, and to specify the inter-assay variability and concentration linearity of our analytic System (CMA600, Sweden).
For in vivo testing male Sprague-Dawley rats underwent multimodality monitoring, including ECG, arterial BP, CVP, EtCO2, SpO2 and core temperature. A microdialysis probe (CMA11; 2mm) was introduced into a guide cannula, which was stereotactically implanted 3 days before the experiment into the right hippocampus (histologically verified after necropsy). As reference for peripheral metabolism a second probe was inserted into the right femoral vein.
Results: In vitro testing indicated that a flow rate of 1μl/min is sufficient to achieve acceptable recovery values (10-20%) and a temporal resolution of 8 minutes for the most reliable metabolic parameters, i.e. lactate, pyruvate, glutamate and glucose. By introducing this flow rate in our cardiac arrest model we were able to identify 3 main phases: initial surgical trauma, baseline conditions (after preparation and at least 1 hour after probe insertion) and ischemia during cardiac arrest. Compared to peripheral metabolism, cerebrally major deviations were observed during ischemia.
Conclusion: Based on this optimized setting we established a reliable and solid model to investigate the impact of resuscitation methods on cerebral metabolism, highlighting the importance of concomitant peripheral and cerebral monitoring.
Author Disclosures: A. Hosmann: None. A. Schober: None. A. Gruber: None. F. Sterz: None. C. Testori: None. A. Warenits: None. W. Weihs: None. S. Högler: None. T. Scherer: None. A. Janata: None. A. Laggner: None. M. Zeitlinger: None.
- © 2014 by American Heart Association, Inc.