Intracranial Pulsating Balloon-Based Cardiac-Gated ICP Modulation Impact on Brain Oxygenation: A Proof-of-Concept Study in a Swine Model.

Abstract

Brain oxygenation improvement is a sought-after goal in neurocritical care patients. Previously, we have shown that cerebral blood flow improvement by cardiac-gated intracranial pressure (ICP) modulation using an intracranial pulsating balloon is feasible in a swine model. We sought to explore specific ICP modulation protocols to assess the feasibility of influencing brain oxygenation. A previously presentedelectrocardiogram (ECG)-gated intracranial balloon pump in which volume, timing, and duty cycle of balloon inflation could be altered was used. Different protocols were tested in a swine model of normal and elevated ICP attained by intracranial fluid infusion with continuous monitoring of physiological parameters, andbrain tissue oxygen tension (PbtO2)was measured at baseline and after device activation. We studied five swine, subjected to two main protocols differing in their phase relative to the cardiac cycle. In reduced brain perfusion status (ICP > 20mm Hg, PbtO2 < 15mm Hg), the late-diastolic-early-systolic (Inflation/deflation) protocol showed consistent elevation in PbtO2 (+ 9%, p < 0.01), coupled with ICP reduction (- 12%, p < 0.01), whereas the early-systolic-late-diastolic (inflation/deflation) protocol resulted in PbtO2 reduction (- 4%, p < 0.01), coupled with ICP increase (+ 5% above baseline, p < 0.01). No significant changes in brain oxygenation or ICP were observed at normal perfusion status (ICP < 20mm Hg, PbtO2 > 15mm Hg). Intracranial cardiac-gated balloon pump activation can influence cerebral oxygenation and raise PbtO2 above threshold values. This study supports the concept of late-diastolic pressure rise, coupled with early-systolic pressure drop, as a potential effector of flow augmentation leading to improve brain tissue oxygenation. Further studies are warranted to assess the translational potential of using an intracranial cardiac-gated balloon pump device to improve brain tissue oxygenation.