Effectiveness of Adaptive Servo Ventilation in the treatment of hypocapnic central sleep apnea of various etiologies.

Background: Central sleep apnea (CSA) occurs in clinical situations that induce hypocapnia and respiratory instability during sleep. This is true, not only in heart failure patients, but also in patients suffering from neurological diseases and idiopathic CSA. Adaptive Servo Ventilation (ASV) is frequently prescribed in France for the treatment of CSA, but only a few studies have evaluated ASV treatment with regards to long term effectiveness and compliance.

Methods: Retrospective chart review in two French centers of the outcome of 74 CSA patients treated by ASV with a mean follow up on ASV of 36±18 months.

Results: Thirty-three of the 74 patients suffered from CSA related to heart failure (HF), whereas the 41 others exhibited CSA mainly associated with neurological disorders or idiopathic CSA. Mean ASV compliance was 5.2±2.6 and 5.9±2.9h per night in cardiac failure and non-cardiac failure patients, respectively. All patients significantly improved their apnea+hypopnea index (from 47.4±19.8 to 6.9±9.3/h [p<0.001]) and mean nocturnal SaO(2) (from 92.1±2.6% to 93.6±3.2% [p<0.001]). The Epworth sleepiness scale score was reduced from 10.2±5.2 to 6.5±3.9 (p<0.01) in compliant patients but not in non-compliant patients (less than 3h per night). Moreover, compliant cardiac failure patients demonstrated a significant improvement in their NYHA score [p<0.05]. Lastly, ASV significantly reduced chronic hyperventilation as assessed by blood gases.

Conclusion: Our findings suggest that ASV is well tolerated and effective for most patients with hypocapnic central sleep apnea and chronic hyperventilation.