Clinical advantages of reduced expiratory positive airway pressure setting in adaptive servo-ventilation therapy

The clinical ramifications of adaptive servo-ventilation (ASV) therapy have stirred debate within the medical community. Given the potential detrimental effect of elevated expiratory positive airway pressure (EPAP) on cardiac output, we hypothesized that relatively lower EPAP may be recommended for successful ASV therapy. In-hospital patients with congestive heart failure refractory to medical therapy were included in the prospective cohort study of ASV therapy on prognosis in repeatedly hospitalized patients with chronic heart failure: longitudinal observational study of effects on readmission and mortality (SAVIOR-L) study. Assignment to either the ASV treatment group or the medical management group was at the discretion of the attending physicians. For the purposes of this retrospective study, our focus remained solely on the ASV cohort. We conducted an extensive analysis to elucidate the influence of lower EPAP settings on midterm mortality. A total of 108 patients were included. The median age was 74 years, and 83 (77%) patients were male. The median EPAP setting employed was 4 cmH₂O, with 60 patients subjected to EPAP levels below 5 cmH₂O. There were no significant differences in the baseline characteristics between the lower and higher EPAP groups, which were divided at the EPAP cutoff of 4.5 cmH₂O (p > 0.05 for all). A trend toward reduced mortality emerged among patients with EPAP settings below 5 cmH₂O, exhibiting a hazard ratio of 0.48 (95% confidence interval 0.22-1.07, p = 0.072) after adjusting for potential confounding factors: 2-year mortality 26% vs. 38%; p = 0.095. Heart failure readmission rates were not significantly different between the two groups (p = 0.61). The adoption of relatively lower EPAP settings during ASV therapy may be advisable. Such an approach has the potential to ameliorate mortality rates while concurrently maintaining heart failure recurrence rates at levels commensurate with those with default EPAP settings.