TY - JOUR T1 - Spontaneous Breathing Patterns During Maximum Extracorporeal CO<sub>2</sub> Removal in Subjects With Early Severe ARDS JF - Respiratory Care SP - 911 LP - 919 DO - 10.4187/respcare.07391 VL - 65 IS - 7 AU - Elena Spinelli AU - Tommaso Mauri AU - Alfredo Lissoni AU - Stefania Crotti AU - Thomas Langer AU - Marco Albanese AU - Carlo Alberto Volta AU - Carla Fornari AU - Paola Tagliabue AU - Giacomo Grasselli AU - Antonio Pesenti Y1 - 2020/07/01 UR - http://rc.rcjournal.com/content/65/7/911.abstract N2 - BACKGROUND: Switching patients affected by early severe ARDS and undergoing extracorporeal membrane oxygenation (ECMO) from controlled ventilation to spontaneous breathing can be either beneficial or harmful, depending on how effectively the breathing pattern is controlled with ECMO. Identifying the factors associated with ineffective control of spontaneous breathing with ECMO may advance our pathophysiologic understanding of this syndrome.METHODS: We conducted a prospective study in subjects with severe ARDS who were on ECMO support ≤ 7 d. Subjects were switched to minimal sedation and pressure-support ventilation while extracorporeal CO2 removal was increased to approximate the subject’s total CO2 production (). We calculated the rapid shallow breathing index (RSBI) as breathing frequency divided by tidal volume. We explored the correlation between certain characteristics recorded during pretest controlled ventilation and the development of apnea (ie, expiratory pause lasting &gt; 10 s; n = 3), normal breathing pattern (ie, apnea to RSBI ≤ 105 breaths/min/L; n = 6), and rapid shallow breathing (RSBI &gt; 105 breaths/min/L; n = 6) that occurred during the test study.RESULTS: The ratio of extracorporeal CO2 removal to the subjects’ was &gt;90% in all 15 subjects, and arterial blood gases remained within normal ranges. Baseline pretest Sequential Organ Failure Assessment score, total and ventilatory ratio increased steadily, whereas / was higher in subjects with apnea compared to intermediate RSBI ≤105 breaths/min/L and elevated RSBI &gt;105 breaths/min/L. In subjects with rapid shallow breathing, baseline lung weight measured with quantitative computed tomography scored higher, as well.CONCLUSIONS: In early severe ARDS, the factors associated with rapid shallow breathing despite maximum extracorporeal CO2 extraction include less efficient CO2 and O2 exchange by the natural lung, higher severity of organ failure, and greater magnitude of lung edema. ER -