Novel Ramp Test to Optimize Pressure Setting of Adaptive Servo-Ventilation Using Non-Invasive Lung Fluid Level Quantification.

BACKGROUND Optimal patient selection and device pressure settings are key to successful adaptive servo-ventilation therapy, but there is no established strategy thus far. Adaptive servo-ventilation therapy at an inappropriately high pressure setting for those without pulmonary congestion decreases cardiac output and worsens clinical outcomes. The remote dielectric sensing system (ReDS) is a novel noninvasive tool to estimate the lung fluid amount. The ReDS might be a promising tool for successful adaptive servo-ventilation therapy if appropriately utilized for optimal patient selection and device pressure setting. CASE REPORT An 83-year-old woman was admitted to our hospital to treat acute decompensated heart failure with preserved ejection fraction that was refractory to conventional medical therapy. Following the confirmation that she had significant pulmonary congestion with 47% of the ReDS value (normal range, 20-35%), we performed a "ramp test" to optimize device pressure, by measuring ReDS values and noninvasively estimating the cardiac output and stroke volume at each pressure setting. The device pressure setting was finally determined to minimize pulmonary congestion and maximize cardiac output. Following the continuous adaptive servo-ventilation therapy with the optimized pressure setting, the patient's hospitalization was uneventful and she was discharged. CONCLUSIONS We propose performing a ramp test to optimize the pressure setting of adaptive servo-ventilation by utilizing ReDS technology for each patient, instead of using a default or inappropriately higher pressure setting. However, further studies including large patient populations are warranted to validate the prognostic implication of this customized ramp test protocol.