Overnight pulse oximetry may be helpful for the assessment of therapy efficacy and supporting post-activation hypoglossal nerve stimulation (HNS) titration in patients with moderate to severe obstructive sleep apnea (OSA), according to a case series analysis published in the Journal of Clinical Sleep Medicine.
The first patient in this case series was a 62-year-old man with a history of severe residual OSA. The patient began measuring overnight oximetry levels with a wireless pulse oximetry after HNS implant surgery but before device activation. There was an immediate improvement in O2 parameters, even at low settings. The self-reported response from the patient was deemed “outstanding.” The physicians treating the patient proceeded to an effectiveness home sleep apnea test (eHSAT) rather than the planned titration polysomnogram (tPSG) which was precluded by the pandemic. There was a robust objective response on the eHSAT, leading the treating physicians to delay tPSG indefinitely.
A 70-year-old woman with asthma and severe OSA was also included in this case series. This patient received an HNS implantation after demonstrating a tongue-base-related obstruction on drug-induced sleep endoscopy. The patient then chose to record overnight oximetry as she commenced on HNS treatment. There was a “robust self-reported and oximetry response,” according to the study investigators. The investigators also observed an excellent objective response following the start of an eHSAT. The treating physicians also decided to delay the tPSG because of the clear efficacy of the HNS.
Another case included a 58-year-old man with moderate OSA without hypoxemia but with multilevel collapse. The patient decided to receive HNS despite having complete oropharyngeal wall collapse. After hearing about the prior patient’s success with nocturnal oximetry, the patient opted for this approach as he started HNS. There was an “excellent” self-reported response to overnight oximetry, but the oximetry data were reportedly mixed. The patient’s discomfort with the procedure precluded his continuation beyond the fourth setting; however, he continued to report satisfaction with his improvements in excessive daytime sleepiness. The physicians started an eHSAT, which improved the patient’s condition to mild OSA.
The major limitation of this study was the inclusion of only 3 cases, which may limit the generalizability across a larger patient population. Additional limitations include the inherent underestimation of OSA severity and that the interpreting physician could not know for sure when therapy was paused or timed out.
The study researchers concluded that “the addition of pulse oximetry to self-reported improvements during HNS home titration seems to be of value” and the implications of the study’s findings “include positive patient reinforcement, identification of readiness for tPSG, and possibly proceeding directly to eHSAT.”
Huyett P, Stagnone R. Use of overnight pulse oximetry and a type 3 sleep study to titrate hypoglossal nerve stimulation therapy. J Clin Sleep Med. 2020;16(12):2109-2111. doi:10.5664/jcsm.8754