Cerebral cortex and respiratory muscle perfusion and oxygenation responses between patients failing or succeeding the SBT

Abstract

Introduction: A decrease in perfusion of splanchnic organs and in oxygenation of non-working muscles during spontaneous breathing trial (SBT) has been associated with SBT failure. However, responses of the cerebral cortex and respiratory muscles during the transition from mechanical ventilation (MV) to SBT have not been investigated. Objective: To examine whether perfusion and oxygenation of the cerebral cortex and respiratory muscles evolve differentially between patients failing or succeeding the SBT. Methods: In 29 patients admitted to the medical ICU, blood flow index and oxygenation were simultaneously assessed in the prefrontal cerebral cortex, inspiratory, expiratory and in a non-working muscle by near-infrared spectroscopy during MV and SBT (30-min trial). Cardiac output was monitored continuously and arterial oxygen content was calculated by blood gases. Results: The SBT failure group presented lower oxygenation in all tissues (Table 1). Nevertheless, from MV to SBT, there were no significant different responses neither in the cerebral cortex nor in respiratory muscle perfusion and oxygenation between SBT failure and success group (Table 1). Conclusion: Despite lower oxygenation in the tissues of the SBT failure group, the evolution of cerebral cortex and respiratory muscle perfusion and oxygenation from MV to SBT did not differ in patients who either failed or succeeded the SBT.