| Popis: |
Rationale: This study used an unreleased, modified noninvasive ventilator (BiPAP A40, Philips/Respironics, Monroeville, PA) using Forced Oscillation Technique (FOT) and the method of Dellaca et al (2004) to dynamically measure ∆Xrs and display an Expiratory Flow Limitation (EFL) index and optionally, adjust PEEP (PEEPopt) to abolish EFL. This information could be used to guide a physician’s plan of care and aid in determining if a Noninvasive Ventilator (NIV) is appropriate for the patient. Methods: Twelve naive NIV participants diagnosed with COPD were fitted with an oral-nasal facemask and instructed to breathe normally in the seated position, then in the supine position. The ventilator was set to non-therapy EFL screening mode that delivered 3 cmH20 CPAP pressure. Sessions lasted 5 minutes. If the ventilator displayed the presence of EFL, the participant remained supine to complete a third session where the ventilator titrated PEEPopt starting at 4 cmH20 with a fixed PS at 6 cmH2O. Results: Demographic and physiologic variables are presented in Table 1. All participants showed an increase in their ∆Xrs value from the seated to supine position. Conclusion: A simple process of identifying patients with EFL can be incorporated into a noninvasive ventilator in order to guide clinicians towards different therapeutic strategies, as well as, the option to provide automated therapy to abolish expiratory flow limitation. |
