Abstract 2056: The Intrathoracic Pressure Regulator Improves Cerebral Perfusion Pressures and Carotid Blood Flow in a Porcine Model of Traumatic Brain Injury
Introduction: Traumatic brain injury is the leading cause of death and disability in children and adults in their most productive years. We previously showed that use of the intrathoracic pressure regulator (ITPR) to generate negative intrathoracic pressure during the expiratory phase of ventilation improves 24-hour survival, coronary perfusion pressures, and mean arterial pressure (MAP) in porcine models of hemorrhagic shock and cardiac arrest.
Hypothesis: Application of the ITPR for 60 minutes will increase cerebral perfusion pressures (CerPP) in a porcine model of traumatic brain injury.
Methods: Six female pigs (27.8 ± 2.4 kg) were subjected to focal brain injury by insertion of an epidural foley catheter inflated with 3 ml of saline. Animals were treated for 60 minutes with the ITPR (CirQlatorTM, Advanced Circulatory Systems, Minneapolis, MN) set to a negative expiratory phase pressure of −9 mmHg. The device was then removed and animals were evaluated for 60 additional minutes. Ventilatory parameters were carefully controlled to maintain an end tidal CO2 of 40 mmHg throughout the study. CerPP and carotid blood flow (CBF) was evaluated. CerPP was calculated as MAP minus mean ICP. Results are reported as means ± STD; t = time in minutes. Physiological parameters were analyzed with paired t-tests.
Results: The ITPR significantly improved mean CerPP and CBF. Mean baseline CerPP was 49.4 ± 10.6 mmHg. Mean CerPP (mmHg) after 15, 30, and 45 minutes of ITPR use was significantly improved when compared to baseline (57.5 ± 9.6 (t=15, p=0.008), 58.8 ± 10.2 (t=30, p=0.03), 60.9 ± 10.8 (t=45, p=0.003)). CerPP significantly declined when device use was discontinued (42.5 ± 9.7 (t=45 post device removal, p=0.013), 42.4 ± 8.6 (t=60 post, p=0.02) vs 58.9 ± 12.6 prior to device removal) and was significantly lower than CerPP recorded during device use (@ t=45, p=0.003; @ t=60, p=0.02). CBF (ml/min) was significantly higher when the ITPR was used vs when the device was not used (158 ± 52 vs 117 ± 26 (t=30, p=0.02); 149 ± 49 vs 120 ± 30 (t=45, p=0.03)).
Conclusion: In this anesthetized pig model of traumatic brain injury, treatment with the ITPR significantly improved CerPP and CBF. This therapy may be of clinical value in optimizing cerebral perfusion in states of elevated ICP.