Artikel
Correlation of cerebral monitoring and histopathological results in a standardized trauma model in sheep
Zerebrales Monitoring und histopathologischer Befund - Untersuchung zur Korrelation am standardisierten Trauma Modell des Schafs
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Autoren
Veröffentlicht: | 4. Mai 2005 |
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Gliederung
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Objective
The underlying mechanisms of severe traumatic brain injuries (TBI) are complex. Multiple factors are responsible for the patient’s outcome. Various experimental models imitate only single mechanisms of the TBI. We present our first results of a modified standardized head impact model in sheep, which will make a validation of different therapeutic regimes possible.
Methods
Fifteen sheep (3 SHAM) were instrumented with monitoring probes (arterial and sinus sagital catheters, intracranial pressure monitoring (ICP), internal carotid flow- and polarographic tissue O2 probes (ptiO2). During anaesthesia and mechanical ventilation, standardized TBI was induced by temporo-parietal head impact triggered by a non-penetrating stunner with adjustable forces. Time of investigation was 14h following TBI. Histopathology of the brain was investigated with different staining-methods and immunohistochemistry.
Results
Head impact increased ICP from 9.5±1.2 to 22.5±7 mmHg and decreased internal carotid blood flow (ICBF) from 170±15 to 115±10 ml/min. Initial ptiO2 was 23.6±2.6 mmHg before and 9.7±2.2 mmHg 1h after TBI, respectively. Cerebral metabolic rate of oxygen (CMRO2) dropped from 9.8±1.4 to 6.8±2.0 1h after TBI. All brains (n=12) showed a generalized edema, eleven demonstrated a traumatic subarachnoid haemorrhage, in nine combined with intracranial contusions (contre-coup). In eleven brains, diffuse axonal injury could be demonstrated. All data are mean±SD. Immunohistochemistry (TUNEL, Caspase 3) for evaluation of apoptosis is still in progress.
Conclusions
This modified experimental head impact model demonstrates comparable monitoring data and similar patterns of neuropathological damage in all investigated animals. It is now applied for standardized investigation of therapeutic regimes (e.g. hyperbaric oxygenation) to prevent secondary brain damage.