Variable negative external pressure-an alternative to continuous positive airway pressure for the treatment of obstructive sleep apnea: a pilot study

Abstract

Study objectives: To assess variable negative external pressure (vNEP) therapy using a range of pressures and varying collar sizes and shapes to identify combinations that improve the efficacy and comfort of this emerging therapy for obstructive sleep apnea (OSA).

Methods: This prospective, open-label pilot study included 28 eligible patients (71% men) having documented moderate OSA (apnea-hypopnea index [AHI] 15 events/h ≤ AHI ≤ 30 events/h) at 1 sleep clinic for an overnight, in-lab sleep trial. Each participant tested at least 2 of 6 available vNEP devices during sleep periods ≥ 2 hours. During the assessment of AHI by polysomnography, negative pressures of -20 cm H2O to -35 cm H2O were adjusted to improve each patient's response. Participants' therapeutic preferences were assessed by a questionnaire and interviews.

Results: Twenty (71%) of the participants responded to vNEP therapy: excellent response (AHI ≤ 5 events/h) was observed in 14 (50%); 6 (21%) achieved a partial response (AHI ≤ 50% baseline). For the 20 responders, the therapy reduced the fraction of total sleep time when peripheral oxygen saturation < 90% and improved minimum pulse oximetry oxygen saturation. Six patients experienced a minor, self-limited adverse event. Twenty-six participants (93%) stated that they would use vNEP nightly.

Conclusions: In this pilot study, vNEP therapy markedly improved AHI and oxygenation in most patients with moderate OSA. The majority of participants found vNEP comfortable and preferable to prevailing OSA therapies. Further development and studies of vNEP are warranted.

Clinical trial registration: Registry: ClinicalTrials.gov; Name: Study of Variable Negative External Pressure (vNEP) in Reducing Respiratory Event in Individuals With OSA; URL: https://ichgcp.net/clinical-trials-registry/NCT04718142; Identifier: NCT04718142.

Citation: Kram JA, Pelayo R. Variable negative external pressure-An alternative to continuous positive airway pressure for the treatment of obstructive sleep apnea: A pilot study. J Clin Sleep Med. 2022;18(1):305-314.

Keywords: medical device; negative pressure therapy; obstructive sleep apnea.

Conflict of interest statement

All authors have seen and approved this manuscript. Work for this study was performed at California Center for Sleep Disorders, San Leandro, California. Research for an investigational device was funded by Somne LLC. Dr. Kram and Dr. Pelayo report being consultants to the sponsor, with both being shareholders in the sponsor.

© 2022 American Academy of Sleep Medicine.

Figures

Figure 1. Illustration of variable negative external pressure collar.

Figure 2. Illustration of prototype of variable negative external pressure collar.

Negative pressure applied to the front of the neck by the vNEP collar reduces apnea and hypopnea events by opening the airway. vNEP = variable negative external pressure.

Figure 3. Responses to vNEP treatment by race of participants.

Participants self-identifying as Asian/Pacific Islander, Black, White, and other race/ethnicity (Middle Eastern) responded to vNEP therapy, but the small size of this study and confounding factors preclude analyses by racial/ethnic categories. vNEP = variable negative external pressure.

Figure 4. Changes in AHI during therapy.

Decreases in AHI to below 5 events/h indicated that 14 participants (50%) exhibited an excellent response to vNEP treatment (green lines). Another 6 participants experienced a partial response to the therapy (blue lines). AHI = apnea-hypopnea index, vNEP = variable negative external pressure.

Figure 5. Changes in SpO2 during sleep.

(Top) During vNEP treatment, the fraction of sleep time during which SpO2 < 90% decreased (green lines) for all but 6 participants measured. (Bottom) vNEP therapy also increased the minimum SpO2 measured during sleep (green lines) for all but one participant. SpO2 = oxygen saturation, TST = total sleep time, vNEP = variable negative external pressure.

Figure 6. Comfort participants felt wearing the vNEP device.

None reported discomfort and 93% rated the collars comfortable or very comfortable. vNEP = variable negative external pressure.

Figure 7. Participant comparison to other OSA treatments.

Of those who had experience using CPAP or an oral appliance, 86% rated the vNEP therapy more comfortable or much more comfortable. CPAP = continuous positive airway pressure, OSA = obstructive sleep apnea, vNEP = variable negative external pressure.

Figure 8. Participant willingness to use vNEP nightly.

The 89% positive or very positive response to this question suggests that adherence to vNEP therapy may be high in longer-term trials. vNEP = variable negative external pressure.