O bstructive sleep apnea (OSA) is a common disorder that affects sleep and quality of life. Because many people with OSA cannot or will not comply with the standard treatment with a continuous positive airway pressure (CPAP) mask, alternative treatments have been sought. Upper-airway stimulation using unilateral stimulation of the hypoglossal nerve is a possible option. This multicenter, prospective, single-group, cohort trial and a follow-up randomized therapy-withdrawal trial were performed to evaluate the clinical safety and effectiveness of upper-airway stimulation for treating moderate to severe OSA.Patients who had difficulty accepting or adhering to CPAP treatment were included and served as their own controls. After initial screening, including polysomnography, qualified patients underwent surgery to implant the upper-airway stimulation system in which a stimulation electrode was placed on the hypoglossal nerve to recruit tongue-protrusion function. The sensing lead was placed between the internal and external intercostal muscles to detect ventilatory effort, and the neurostimulator was implanted in the right ipsilateral midinfraclavicular region. A month after implantation, patients had a second baseline diagnostic polysomnographic exam before the device was activated. Patients used a controller to initiate and stop therapy each night and then were assessed at 2, 3, 6, 9, and 12 months. The primary outcome was the change in the severity of OSA as determined by the apneahypopnea index (AHI; number of apnea or hypopnea events per hour; score ≥15 indicates moderate to severe OSA) and the O 2 desaturation index (ODI; number of times per hour of sleep that the blood O 2 level drops by ≥4 percentage points from baseline). At the 12-month assessment, a response to treatment was defined as an AHI reduction of 50% or greater from baseline and a score of less than 20 events per hour along with an ODI reduction of 25% or greater from baseline. The primary efficacy objectives were response rates of 50% or greater as assessed in the AHI and ODI. Secondary outcomes were the Epworth Sleepiness Scale, the Functional Outcomes of Sleep Questionnaire (FOSQ), and the percentage of sleep time with the O 2 saturation of less than 90%. Consecutive patients with a response were included in a randomized controlled therapywithdrawal trial in which they were assigned in a 1:1 ratio to either the therapy-maintenance or therapy-withdrawal group. The withdrawal group had the device turned off for 7 days; the maintenance group continued using the device. Polysomnography was done to measure the effects of withdrawal compared with continued use of therapy. Serious adverse events were those that led to death, lifethreatening illness, permanent impairment, or new or prolonged hospitalization with serious health impairment.Of the 126 participants, 83% were men; mean age was 54.5 years, and mean body mass index was 28.4 kg/m 2 . The mean AHI score on the initial screening polysomnography was 32.0 events per hour, and the mean ODI score was ...

Objectives/Hypothesis:Previous feasibility studies have shown that electrical stimulation of the hypoglossal nerve can improve obstructive sleep apnea (OSA). The current study examined the safety and preliminary effectiveness of a second generation device, the Upper Airway Stimulation (UAS) system, and identified baseline predictors for therapy success.Study Design:Two consecutive open prospective studies.Methods:UAS systems were implanted in patients with moderate to severe OSA who failed or were intolerant of continuous positive airway pressure (CPAP). The study was conducted in 2 parts. In part 1, patients were enrolled with broad selection criteria. Apnea hypopnea index (AHI) was collected using laboratory‐based polysomnography at preimplant and postimplant visits. Epworth Sleepiness Scale (ESS) and Functional Outcomes of Sleep Questionnaire (FOSQ) were also collected. In part 2, patients were enrolled using selection criteria derived from the experience in part 1.Results:In part 1, 20 of 22 enrolled patients (two exited the study) were examined for factors predictive of therapy response. Responders had both a body mass index ≤32 and AHI ≤50 (P < .05) and did not have complete concentric palatal collapse. Part 2 patients (n = 8) were selected using responder criteria and showed an improvement on AHI from baseline, from 38.9 ± 9.8 to 10.0 ± 11.0 (P < .01) at 6 months postimplant. Both ESS and FOSQ improved significantly in part 1 and 2 subjects.Conclusions:The current study has demonstrated that therapy with upper airway stimulation is safe and efficacious in a select group of patients with moderate to severe OSA who cannot or will not use CPAP as primary treatment. Laryngoscope, 2012

The findings demonstrate the feasibility and therapeutic potential for hypoglossal nerve stimulation in obstructive sleep apnea.

The exact influence of sleep-related breathing disorder (SRBD) on blood pressure control remains unknown. We investigated the influence of different degrees of SRBD on daytime blood pressure and its association to documented hypertension by examining 1,190 consecutive patients referred for diagnosis of SRBD. The protocol includes clinical interview, physical examination, office blood pressure measurement, cholesterol, and blood gas analysis. Unattended home monitoring of nocturnal breathing was performed for assessment of SRBD activity (respiratory disturbance index [RDI]). RDI was independently and linearly associated with systolic blood pressure (unstandardized coefficient [B] = 0.07 +/- 0.03, p = 0.03), diastolic blood pressure (B = 0.07 +/- 0.02, p = 0 < 0.001), and heart rate (B = 0.10 +/- 0.02, p < 0.001) at rest. The relative risk for hypertension (blood pressure >/= 160/95 mm Hg) increased with SRBD severity (odds ratio [OR], 4.15 for RDI >/= 40 versus < 5 [95% CI, 2.7 to 6.5]). This relative risk was also elevated in younger ( 50 yr) (OR, 7.15 versus 2.70 for RDI >/= 40 versus < 5). These cross-sectional clinical data suggest a relationship between SRBD severity and systolic blood pressure, diastolic blood pressure, and heart rate after control for confounders such as body mass index (BMI), age, alcohol/nicotine consumption, cholesterol level, and daytime PO(2) and PCO(2). SRBD is an independent risk factor for systemic hypertension with an increased likelihood in subjects

Collapsibility of the upper airways has been identified as an important pathogenic factor in obstructive sleep apnea (OSA). Objective measures of collapsibility are pharyngeal critical pressure (Pcrit) and resistance of the upstream segment (Rus). To systematically determine the effects of sleep stage and body position we investigated 16 male subjects suffering from OSA. We compared the measures in light sleep, slowwave sleep, REM sleep and supine vs. lateral positions. The pressure-flow relationship of the upper airways has been evaluated by simultaneous readings of maximal inspiratory airflow (Vimax) and nasal pressure (p-nCPAP). With two-factor repeated measures ANOVA on those 7 patients which had all 6 situations we found a significant influence of body position on Pcrit (p<0.05) whereas there was no significant influence of sleep stage and no significant interaction between body position and sleep stage. When comparing the body positions Pcrit was higher in the supine than in the lateral positions. During light sleep Pcrit decreased from 0.6 ± 0.8 cm H 2 O (supine) to-2.2±3.6 cm H 2 O (lateral) (p<0.01), during slow-wave sleep Pcrit decreased from 0.3±1.4 cm H 2 O (supine) to-1.7±2.6 (lateral) (p<0.05) and during REM sleep it decreased from 1.2±1.5 cm H 2 O to-2.0±2.2 cm H 2 O (p<0.05). Changes in Rus revealed no body position nor sleep-stage dependence. Comparing the different body positions Rus was only significantly higher in the lateral position during REM sleep (p<0.05). The results indicate that collapsibility of the upper airways is not mediated by sleep stages but is strongly influenced by body position. As a consequence lower nCPAP pressure is needed during lateral positions compared to supine positions.