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

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 30 events/h) <= AHI <= 30 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' 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.