M. De Lima Oliveira, A. Ferreira De Andrade, A. Rodrigo Belon, W. Silva Paiva, M. Shimidt Soares, G. Cataxo Patriota, C. Nobrega Nascimento, J. Pinhata Otoch, B. Chian Ping Jeng, M. Jacobsen Teixeira, E. Bor-Seng-Shu
Department of Neurology, University Hospital, University of São Paulo – São Paulo, Brazil
Objective: The image of the real-time ultrasound combined with pulsed Doppler system is a noninvasive and bedside method that allows the cerebral blood flow velocity and evaluation and flow resistance measurement in intracranial hypertension patients. The intracranial hypertension is an important clinical condition and represents high risk to patients with acute brain injury. In this study, we describe in an experimental model, application of cerebral duplex to evaluate changes in pre and post-intracranial hypertension.
Material and Methods: An experimental study, using 30 crossbred Landrace and Duroc pigs weighing approximately 18–20 kg and aged 2months. Prior to surgery, pigs were starved for 12 h but had free access to water. We co-administered intramuscular ketamine at dose of 15mg/kgand xylazine at a dose of 2 mg/kg. The experimental hypertension was performed with an intracranial balloon. At each intervention we performed a neurological assessment of the pupils and Doppler exam (Ultrasound color duplex SonoSite-Micromax). Continuous intracranial pressure measurement by intraparenchymal and extradural catheters was also performed. The animals underwent to a baseline measurement, a pre-balloon insufflation, a post-balloon insufflation before and after saline solution infusion. The association of the results of duplex was compared with ICP and systemic monitoring. In complementary we measured optic nerve sheath diameter by ultrasound in each phase.
Results: All animals were closely observed for changes for 1.5 h after the start of the expansion, and then the mock clinical intervention was made (3% hypertonic saline solution). The model allows the determination of a decrease in intracranial compliance by refractory IH. A sudden change in mean MBP lead to a simultaneous change in cerebral blood flow velocities and pulsatilite index initially.
Discussion: In our model was possible to perform the evaluation of brain hemodynamic changes with TCD without problems in all tested animals.
Key words: animal model, intracranial hypertension, transcranial color duplex.