Respiratory center function in patients under adaptive servoventilation: etiology and outcome.

Abstract

Study objectives: Central sleep apnea (CSA) is a sleep disorder characterized by instability in the respiratory center's (RC) function, leading to an excessive ventilatory response. The most effective treatment for these patients is adaptive servo-ventilation (ASV). We hypothesize that individuals with CSA may exhibit hyperresponsiveness of the RC, and ASV treatment could normalize its function. We aimed to measure the ventilatory response to hypercapnia (VRH) and its relationship with the outcomes following ASV treatment.

Methods: A prospective study with repeated measurements was conducted on subjects with CSA treated with ASV. A VHR test was performed using p0.1/pEtCO₂ determinations: a first determination at the time of inclusion and a second one after at least six months of ASV treatment. We used the Pearson correlation test and the comparison of means (t-test) for independent and paired variables for statistical analysis. A p0.1/pEtCO₂ value of 0.43 cmH₂O/mmHg was considered a reference value.

Results: We analyzed 46 subjects, 82% male. AHI 47/h (23), central AHI 27/h (12). The initial p0.1/pEtCO₂ was 0.48 (0.24) cmH₂O/mmHg, significantly higher than the reference value (p=0.02). After ASV treatment, 63% of subjects normalized p0.1/pEtCO₂ and decreased to 0.37 (0.23) cmH₂O/mmHg, which was significantly lower than the initial value (p=0.015) and comparable to the reference value (p=0.26). CSA secondary to opioid use has a substantially lower p0.1/pEtCO₂: 0.27 cmH₂O/mmHg SD 0.11 (p=0,021).

Conclusions: VRH in patients with CSA and ASV treatment, could differentiate phenotypes and impact on therapeutic decisions.