Pulsatile Perfusion Therapy Protects Internal Carotid Artery Blood Flow and Cerebrovascular Blood Oxygen Saturation with Simulated Hemorrhage in Humans

Pulsatile Perfusion Therapy (PPT), a method we developed to induce 0.1 Hz hemodynamic oscillations (10-second cycles), protects blood oxygen saturation during ischemia. PPT via oscillatory lower body negative pressure (LBNP) protected cerebrovascular blood oxygen saturation (ScO ₂ ) during simulated hemorrhage in humans (induced via LBNP). Thigh cuff compressions are a new approach to achieve similar 0.1 Hz hemodynamic oscillations. We hypothesized that PPT via thigh cuff compressions would attenuate reductions in cerebral blood flow and cerebrovascular blood oxygen saturation during LBNP in humans. Fifteen healthy humans (6F/9M; age, 25.8 ± 4.5 y) completed two protocols of -60 mmHg LBNP. In the PPT condition, thigh cuffs intermittently inflated and deflated in 10-s cycles during the LBNP protocol. In the control condition (CON), the thigh cuffs remained deflated. Internal carotid artery (ICA) blood flow and ScO ₂ were measured continuously. PPT attenuated reductions in ICA blood flow (PPT: -17.6 ± 11.3% vs. CON: -31.0 ± 11.8%; P=0.02) and ScO ₂ (PPT: -5.2 ± 2.4% vs. CON: -7.1 ± 3.6%; P=0.07) compared to CON. These data provide evidence for PPT as a potential intervention for the treatment of cerebral hypoperfusion during hemorrhage.