What is the Optimal Strategy for Adaptive Servo-Ventilation Therapy?

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.

Adaptive Servo-Ventilation as a Novel Therapeutic Strategy for Chronic Heart Failure

The introduction of new therapeutics for patients with chronic heart failure, including sacubitril/valsartan, sodium-glucose cotransporter 2 inhibitors, and ivabradine, in addition to beta-blockers, angiotensin converting enzyme inhibitors, and mineralocorticoid receptor antagonists, lends an opportunity for significant clinical risk reduction compared to what was available just one decade ago. Further clinical options are needed, however, for patients with residual clinical congestion refractory to these therapies. Adaptive servo-ventilation is a novel therapeutic option to address significant clinical volume in cases resistant to medical therapy. The aggregate benefit of these additional therapeutic strategies in addition to foundational medical therapy may be a promising option in the selected candidates who do not achieve acceptable clinical and quality-of-life improvements with oral medical therapy alone. Now is the era to reconsider the implication of an adaptive servo-ventilation-therapy-incorporated medical therapeutic strategy for patients with congestive heart failure.

The level of carbon dioxide is the determinant of successful noninvasive ventilation pressure titration in patients with nonhypercapnic primary central sleep apnea: a case report

Primary central sleep apnea is classified as nonhypercapnic central sleep apnea. High loop gain, lower CO₂ reserves, and other reasons can lead to hypocapnia in patients who develop intermittent hyperventilation during sleep. Therefore, it is necessary to monitor nocturnal CO₂ level for these patients. We report a female patient diagnosed with nonhypercapnic primary central sleep apnea who complained of snoring, apnea, and excessive daytime sleepiness. With the monitoring of transcutaneous partial pressure of CO₂, manual noninvasive ventilation pressure titration was performed with continuous positive airway pressure, bilevel positive airway pressure in a spontaneous-timed mode, and adaptive servo-ventilation mode for 3 nights, respectively. Only adaptive servo-ventilation mode could stabilize the transcutaneous partial pressure of CO₂ above the apneic threshold (approximately 40 mm Hg) with successfully eliminating central apnea events. It is concluded that the level of CO₂ is the determinant of successful noninvasive ventilation pressure titration in patients with nonhypercapnic central sleep apnea.

CITATION

Han X, Zhao D, Wang J, Wang Y, Dong L, Chen B-y. The level of carbon dioxide is the determinant of successful noninvasive ventilation pressure titration in patients with nonhypercapnic primary central sleep apnea: a case report. J Clin Sleep Med. 2022;18(1):319-324.