Authors: Omer Doron; Omer Doron, MD (Holon, Israel)

Introduction: Augmenting brain perfusion or reducing intracranial pressure (ICP) dose is the end target of many therapies in the neuro-critical care unit. Many present therapies rely on aggressive systemic interventions that may lead to untoward effects. Previous studies have used a cardiac-gated intracranial balloon pump (ICBP) to model hydrocephalus or to flatten the ICP waveform. We sought to sought to optimize ICBP activation parameters to improve cerebral physiological parameters in a swine model of raised ICP. Methods: We developed an ECG-gated intracranial balloon pump in which volume, timing, and duty cycle of balloon inflation could be altered. We studied the ICBP in a swine model of elevated ICP attained by continuous intracranial fluid infusion with continuous monitoring of systemic and cerebral physiological parameters. We defined two specific protocols of ICBP activation. Results: We studied 11 swine, three of which were studied to define the optimal timing, volume, and duty-cycle of balloon inflation. Eight swine were studied with two defined protocols at baseline and with ICP gradually raised to a mean of 30.5 mmHg. ICBP activation caused a consistent modification of the ICP waveform. Balloon activation “Protocol A” led to a consistent elevation in CBF (8% to 25% above baseline, p<0.00001). A second protocol (“Protocol B”) resulted in a modest reduction of ICP over time (8% to 11%, p <0.0001) at all ICP levels. Neither protocols significantly affected systemic physiological parameters. Conclusion: Our preliminary results indicate that optimized protocols of ICBP activation may have beneficial effects on cerebral physiological parameters, with minimal effect on systemic parameters. Further studies are warranted to explore whether ICBP protocols may be of clinical benefit in patients with brain injuries with increased ICP.