Hypoglossal nerve stimulation : a new treatment approach for obstructive sleep apnea. A review

Introducción: la apnea obstructiva del sueño (AOS) es el trastorno respiratorio del sueño más frecuente. La terapia de elección es la presión positiva continua de la vía aérea (CPAP), pero se ha descrito mala adherencia en su uso. La estimulación del nervio hipogloso (ENH) se encuentra entre las nuevas modalidades de tratamiento en estudio.Objetivo: revisar la fisiopatología de este trastorno, así como la efectividad y seguridad de la ENH como terapia de la AOS.Metodología: se realizó una búsqueda en la base de datos de Medline utilizando las palabras clave: Sleep Apnea, Syndrome; Sleep Apnea, Obstructive; Hypoglossal Nerve; Electrodes, Implanted; Implantable Neurostimulators, y Electric Stimulation Therapy.Resultados: se encontraron 267 artículos, de los cuales se seleccionaron 27 según los criterios de inclusión y exclusión. Adicionalmente, se hizo una búsqueda secundaria de estos artículos. La ENH ha mostrado un perfil de efectividad y seguridad favorable con alta adherencia como tratamiento de la AOS. Sin embargo, no se recomienda en pacientes con un índice apnea-hipopnea > 50, ya que produce una reducción parcial, inferior que la que puede producir el CPAP.Conclusiones: la ENH ayuda a corregir, parcialmente, uno de los mecanismos fisiopatológicos de la AOS. Si bien en la revisión se encontraron datos que sugieren efectividad y seguridad aceptables en corto plazo, se necesitan más estudios sobre efectividad y seguridad a largo plazo, sobre comparación directa con CPAP en algunos casos y sobre uso bilateral de esta nueva modalidad terapéutica.Artículo de revisión286-296Introduction: Obstructive Sleep Apnea (OSA) is the most common sleep respiratory disorder. Although Continuous Positive Airway Pressure (CPAP) is the treatment of choice, it has poor adherence. The Hypoglossal Nerve Stimulation (HNS) is being studied as a new therapeutic approach. Objective: To review the pathophysiology of this disorder and the effectiveness and safety of HNS as a treatment for OSA. Methods: Information was retrieved from the database Medline using the search terms: Sleep Apnea, Syndrome; Sleep Apnea, Obstructive; Hypoglossal Nerve; Electrodes, Implanted; Implantable Neurostimulators, and Electric Stimulation Therapy. Results: 267 articles were found, of which 27 met the inclusion and exclusion criteria. In addition, a secondary search from these articles was performed. The HNS has shown a favorable effectiveness and safety profile with a high adherence as a treatment for OSA. However, it is not recommended for patients with an Apnea-Hypopnea Index >50 since it only causes a partial reduction of the AHI; a less effective result than the one observed with CPAP. Conclusion: The HNS partially improves one of the pathophysiological mechanisms of OSA. In this review, the data shows an acceptable effectiveness and safety profile in short-term, but more research is needed on the long-term effectiveness and safety of HNS as well as the bilateral use of this new therapy and a clinical study comparing it with CPAP

Effects of Age and Sex on Inspiratory Muscle Activation Patterns During Exercise

Purpose: Characterize the effects of age, sex, and their interaction on inspiratory muscle activation patterns during exercise. Methods: Twenty younger (20-30y, n=10 women) and twenty older (60-80y, n=10 women) subjects performed an incremental cycle exercise test. Electromyography of the scalene (EMGsca) and sternocleidomastoid (EMGscm) muscles were measured using skin surface electrodes, while diaphragm electromyography (EMGdi) and esophageal and transdiaphragmatic pressures were measured using an esophageal catheter. Electromyography data were transformed into root-mean-square with a 100ms time constant. Esophageal (PTPes) and diaphragmatic (PTPdi) pressure-time products were used as indices of total inspiratory muscle pressure production and diaphragmatic pressure production, respectively. Results: At absolute minute ventilations (V E), women and older subjects had greater EMGdi than men and younger subjects, respectively (all p<0.05), but no differences were noted when V E was expressed in relative terms (all p>0.05). Women had greater EMGsca activity than men at absolute and relative levels of V E (all p<0.05). Older subjects had greater EMGsca than younger subjects when V E was expressed relative (all p<0.05) but not absolute terms (all p>0.05). At absolute and relative levels of V E, women and older subjects had greater EMGscm than men and younger subjects, respectively (all p<0.05). Women and older subjects had a greater PTPdi/PTPes at a V E of 70 l·min-1 than men and younger subjects, respectively (both p<0.05), but no differences were noted when V E was expressed in relative terms (all p>0.05). No significant interactions between age and sex were noted (all p>0.05). Conclusion: Age and sex significantly affect inspiratory muscle activation patterns during exercise; however, the extent of the effects depends on whether comparisons are made at a solute or relative V E.This study was supported by the British Columbia Lung Association (BCLA). YMS, PBD, and AHR were supported by graduate scholarships from the Natural Sciences and Engineering Research Council of Canada (NSERC). PBD and MRS were supported by fellowships from the University of British Columbia and BCLA. JAG was supported by a Scholar Award from the Michael Smith Foundation for Health Research, a New Investigator Award from the Providence Health Care Research Institute and St. Paul’s Hospital Foundation, and a Canadian Institutes of Health Research Clinical Rehabilitation New Investigator Award

The Effects Of Beetroot Juice Supplementation On The Oxygen Cost Of Breathing In Obese Males

The purpose of this study was to measure the O2 cost of breathing during a eucapnic voluntary hyperventilation test, and whole body VO2 and ratings of perceived breathlessness during constant work rate cycling in obese males following beetroot juice (BRJ) supplementation. Six (n=6) obese males performed spirometry measures and a VO2peak test on a cycle ergometer during the initial visit. During the remaining two subsequent visits, subjects mimicked the ventilation and breathing pattern corresponding to 50%, 70%, and 90% VO2peak. After a passive recovery period, subjects cycled at a moderate intensity for 6 minutes. Subjects supplemented with either a placebo or BRJ for ten days in a randomized, cross-over design. A 10-day washout period separated the two supplementation periods. The O2 cost of breathing, whole body VO2, or ratings of perceived breathlessness were not different between BRJ and placebo conditions. Tidal volume was reduced during moderate intensity cycling during BRJ conditions when compared to placebo conditions. These findings suggest that BRJ does not lower O2 cost of breathing during eucapnic voluntary hyperventilation, nor does BRJ lower VO2 during moderate intensity cycling in young obese males