Improving Microcirculation with Therapeutic Intrathoracic Pressure Regulation in a Porcine Model of Hemorrhage
ARMY INST OF SURGICAL RESEARCH FORT SAM HOUSTON TX
Pagination or Media Count:
Aim of study Intrathoracic pressure regulation IPR has been used to treat hypotension and states of hypoperfusion by providing positive pressure ventilation during inspiration followed by augmentation of negative intrathoracic pressure during expiration. This therapy augments cardiac output and lowers intracranial pressure, thereby providing greater circulation to the heart and brain. The effects of IPR on microcirculation remain unknown. Methods Using a hemorrhagic model, hemodynamics and sublingual microcirculation were evaluated after a 55 blood loss over a 30 min timeframe in 10 female farm pigs 30 kg previously anesthetized with isoflurane. Results After hemorrhage the mean arterial pressure was 27 4mmHg. Blood cell velocity, the key indicator of microcirculation, was significantly reduced after the bleed from 1033 175 ms pre-bleed to 147 60 ms p 0.0001. Application of an IPR device reduced airway pressure during expiration to 9 mm Hg after each positive pressure breath 10 mLkg, 10 breathsmin and resulted in a rapid increase in systemic hemodynamics and microcirculation. During IPR treatment, average mean arterial pressure increased by 59 to 43 6mmHg p 0.002 and blood cell velocity increased by 344 to 506 99 ms p 0.001. Conclusion In this animal model, we observed that microcirculation and systemic blood pressures are correlated and may be significantly improved by using IPR therapy.
- Anatomy and Physiology
- Medicine and Medical Research