Changes in Hypoxia-Related Metrics With Hypoglossal Nerve Stimulation: A Scoping Review

Hypoxia-related measures are valuable predictors of cardiovascular outcomes in obstructive sleep apnea. This scoping review evaluates existing literature on changes in hypoxia-related measures with hypoglossal nerve stimulation (HGNS).

A systematic search was performed across PubMed, Embase, Web of Science, and Scopus databases.

Population search terms included HGNS and upper airway stimulation. Measures of interest included hypoxic burden, oxygen desaturation index (ODI), and time below 90% or 88% oxygen saturation (T90/T88). Title, abstract, and full-text screenings were conducted by two reviewers. Studies that only reported O₂ nadir or mean were excluded. When multiple studies were based on the same cohort of HGNS patients, the manuscript with the most comprehensive oxygenation measures was included; if these did not differ, the one with the longest period of follow-up was used. Postoperative sleep studies were labeled as titration polysomnography (PSG), full-night PSG at a single voltage, unspecified PSG type, or home sleep test.

In total, 581 articles were identified, 86 underwent full-text review, and 22 studies corresponding to n = 2092 patients met inclusion criteria. There was heterogeneity in sleep testing types across studies. ODI was included in 20 studies (90.9%) and T90/T88 in 13 (59.1%). The majority of studies (15 of 17) demonstrated significant improvement in ODI from pre- to post-HGNS, but not in T90/T88. No studies meeting inclusion criteria reported hypoxic burden.

The available literature suggests improvements in hypoxia-related measures with HGNS, though most report frequency-based measures and there is a dearth of literature examining HGNS and hypoxic burden.