[Sleep-disordered breathing in occupational places: from screening to Health and Productivity Management].

BACKGROUND: Sleep-disordered breathing (SDB), represented by sleep apnea, is highly prevalent in the general population and is associated with alcohol intake and obesity. Since SDB is further associated with hypertension, diabetes, and future cardiovascular diseases, as well as accidents and injuries in workplaces, there is a need for complete SDB assessment in workers, including screening and the application of diagnostic and therapeutic approaches. RESULTS: Currently, it appears that SDB assessment is not sufficiently conducted, even among commercial motor vehicle (CMV) drivers, despite CMV drivers with SDB being at a high risk of serious traffic accidents. Based on a discussion conducted in The Study Group for Sleep Disordered Breathing in Work Places, we summarized the current situation in Japan and tried to elucidate the bottleneck of these approaches. Then, the situation in Japan was compared with that in South Korea; Professor Chol Shin substantiated that the situation in South Korea was similar to that in Japan. However, recently published data on CMV drivers in the United States showed that appropriate treatment of SDB reduced the risk of traffic accidents among CMV drivers. This will encourage the implementation of the required processes, from screening to maintenance of treatment. CONCLUSION: We propose a new approach based on "harmonizing work with treatment and prevention" and "Health and Productivity Management (HPM)" as a solution for implementing SDB programs.

Threshold currents of platinum electrodes used for functional electrical stimulation of the phrenic nerves for treatment of central apnea.

BACKGROUND: Stability of threshold currents during long-term use of phrenic nerve stimulation has been questioned. METHODS AND RESULTS: Between January 5, 1988, and March 5, 2008, 49 patients with functional C2-tetraplegia received an Atrostim PNS (Atrotech Ltd., Tampere, Finland) as treatment of their respiratory insufficiency; a follow-up of 35 of such patients was carried out exclusively in our institution for 6.3 (4.44) 0.04-15.75 years (mean [standard deviation (SD)] range). The device employed four-pole sequential nerve stimulation, which provided four threshold currents subsequently evaluated for each phrenic nerve. Stimulation data were prospectively recorded. The differences between threshold currents recorded 1 year after implantation and the last recorded values were 0.33-0.43 (0.44-0.63) 0-2.9 mA. After having excluded the data of eight patients with values >1 mA (= mean + SD), we registered the differences for the remaining patients of 0.15-0.24 (0.14-0.24) 0-0.95 mA, which is just twice the adjustment accuracy of the device. Out of the eight problem cases one had, and two were suspected to have, surgical trauma; all three nerves recovered. In two cases the values steadily increasing over years might have been caused by unspecific foreign body reaction. Two cases with values >1 mA for different durations at different electrodes might be caused by biofilm, and one patient displaying steadily increasing values lived, unwilling to live, only 2 years after the implantation. CONCLUSION: Thus, there was no permanent nerve injury and in 77% of the presented cases threshold currents remained stable.

[Non-invasive mechanical ventilation therapy in patients with heart failure]. / Kalp yetersizligi hastalarinda noninvaziv mekanik ventilasyon tedavisi.

Non-invasive mechanical ventilation (NIMV) therapy in patients with acute heart failure (HF) improves left ventricular functions via decreasing left ventricular afterload and reduces intubation rate and short-term mortality. In patients with chronic HF, NIMV therapy eliminates central and obstructive apneas and Cheyne-Stokes respiration, and improves morbidity. There are essentially three modes of NIMV that are used in the treatment of HF: Continuous positive airway pressure (CPAP), bilevel positive airway pressure (BIPAP) and adaptive servo-ventilation (ASV). Hereby, NIMV therapy in patients with acute and chronic HF is reviewed as well as methods, indications, effectiveness and complications.

A novel approach to the treatment of central sleep apnea in patients with heart failure.

Central sleep apnea (CSA) is a common, though often unrecognized, finding in congestive heart failure (HF) patients that is associated with poor quality of life and increased morbidity and mortality. While various treatment strategies, including continuous positive airway pressure (CPAP) therapy, have been devised and tested to treat CSA in HF, none thus far have been proven effective over the long term or been shown to improve survival. Adaptive pressure support servo-ventilation (ASV) is a promising potential new therapy for CSA, but like its predecessor, CPAP, it is often not well tolerated by patients, and results from clinical trials evaluating its long-term effectiveness in reducing morbidity and mortality are still a number of years off. Recently, a new therapy utilizing unilateral transvenous phrenic nerve stimulation has been introduced to treat CSA in HF. As a totally implantable, device-based therapy, it may be better tolerated than CPAP or ASV in HF patients and, thus, improve patient compliance with treatment. Early studies using this therapy have been encouraging, with patients demonstrating significant improvement in major indices of CSA severity.

Suitability of the pericardiophrenic veins for phrenic nerve stimulation: an anatomic study.

OBJECTIVE: The objective of this study was to assess the potential of the pericardiophrenic veins (PPVs) as conduits for transvenous stimulation of the phrenic nerves. Modulating respiration with transvenous phrenic nerve stimulation via the PPVs might reduce or eliminate the adverse effects of central sleep apnea in heart failure. METHODS: Forty-eight fixed cadavers were dissected to study the anatomic characteristics of the PPVs and related neurovascular structures. RESULTS: The right PPV, found in only 1 of 35 cadavers, was <0.5 mm diameter. The left PPV, located in all 48 cadavers, drained into the left brachiocephalic vein (BCV) directly or into the BCV via the superior intercostal vein (SICV). Mean ± SD SICV trunk diameter was 4 ± 2 mm. Mean ± SD left PPV diameter was 2 ± 1 mm. The length between the point of separation of the left PPV from the phrenic nerve to its junction with the BCV or SICV trunk ranged from 6 to 40 mm. The angle of approach, defined as the angle formed by the intersection of the longitudinal axis of the BCV and the longitudinal axis of the PPV or SICV trunk, and which represents the angle that would need to be navigated when inserting a stimulation lead into the PPV using a peripheral cannulation approach, was 99 ± 28 degrees. Valves were identified in 54% of left PPVs. CONCLUSIONS: Because of its extremely small size, the right PPV appears unsuitable for transvenous phrenic nerve stimulation. In contrast, the left PPV may be accessible via the left BCV using standard transvenous catheterization techniques; however, the small caliber of the left PPV and the frequent presence of valves within it might pose challenges in navigating the vessel to achieve transvenous phrenic nerve stimulation.

[Reduction of central sleep apnea in heart failure patients with beta-blockers therapy].

BACKGROUND: Sleep apneas are frequent in patients with heart failure (HF). Estimate of the pre-beta blocker age (BB) point out to 45% of central apneas in these patients. OBJECTIVE: Assess the influence of BB in central apneas and their interference in the quality of sleep and life of patients with heart failure. METHODS: 65 patients with heart failure underwent diagnostic polysomnography. Polysomnography have been assessed according to the use or not of BB. On the day of examination, the patients answered the Minnesota questionnaire for quality of life with HF. After 6 and 12 months from the polysomnography date, all patients were contacted by phone, in order to repeat the Minnesota questionnaire. RESULTS: The prevalence of sleep apnea (IAH > 15/h) hit 46.1% in the total population, however, central sleep apnea was identified in 18.4% of patients. The use of BB, in a multivariate analysis, was the only predictor of a minor index of central apnea and hypopnea (IAH) (p=0.002), greater saturation (p=0.02) and smaller average desaturation of oxygen (p=0.03). Additionally, the use of BB could predict a better quality of life after 6 and 12 months (p=0.002 and 0.001 respectively) and a smaller number admissions in these periods (p=0.001 and p=0.05 respectively). CONCLUSION: The use BB reduced the rate of central sleep apnea in total population, if we compare to literature data. Additionally, the BB improved parameters of quality of sleep and life of patients with heart failure.

Redução da prevalência de apneia central em pacientes com insuficiência cardíaca sob uso de betabloqueador / Reducción de la prevalencia de apnea central en pacientes con insuficiencia cardiaca bajo uso de betabloqueante / Reduction of central sleep apnea in heart failure patients with beta-blockers therapy

FUNDAMENTO: As apneias do sono são doenças frequentes em portadores de insuficiência cardíaca (IC). Estimativas da era pré-betabloqueador (BB) apontam para uma prevalência de 45 por cento de apneias centrais nestes pacientes. OBJETIVO: Avaliar a influência dos BB na prevalência das apneias centrais e sua interferência na qualidade do sono e de vida de portadores de IC. MÉTODOS: 65 pacientes portadores de IC foram submetidos a polissonografia diagnóstica.Os resultados da polissonografia foram avaliados de acordo com o uso ou não de BB. No dia do exame os pacientes responderam ao questionário de Minessota para qualidade de vida com IC. Após 6 e 12 meses da data da polissonografia, houve contato telefônico com todos os pacientes, para a repetição do questionário de Minessota. RESULTADOS: A prevalência de apneia do sono (IAH > 15/h) foi de 46,1 por cento na população total, porém a apneia central foi identificada em apenas 18,4 por cento dos pacientes. O uso de BB, em análise multivariada, foi o único preditor de ocorrência de menor índice de apneia e hipopneia (IAH) central (p=0,002), maior saturação (p=0,02) e menor dessaturação média de oxigênio (p=0,03). Além disso, o uso de BB foi preditor de melhor qualidade de vida após 6 e 12 meses (p=0,002 e 0,001 respectivamente) e de menor número de hospitalizações nestes períodos (p=0,001 e p=0,05 respectivamente). CONCLUSÃO: O uso de BB reduziu a incidência de apneia central na população total, se compararmos com os dados da literatura. Além disto, os BB melhoraram parâmetros da qualidade do sono e de vida de portadores de IC.

BACKGROUND: Sleep apneas are frequent in patients with heart failure (HF). Estimate of the pre-beta blocker age (BB) point out to 45 percent of central apneas in these patients. OBJECTIVE: Assess the influence of BB in central apneas and their interference in the quality of sleep and life of patients with heart failure. METHODS: 65 patients with heart failure underwent diagnostic polysomnography. Polysomnography have been assessed according to the use or not of BB. On the day of examination, the patients answered the Minessota questionnaire for quality of life with HF. After 6 and 12 months from the polysomnography date, all patients were contacted by phone, in order to repeat the Minessota questionnaire. RESULTS: The prevalence of sleep apnea (IAH > 15/h) hit 46.1 percent in the total population, however, central sleep apnea was identified in 18.4 percent of patients. The use of BB, in a multivariate analysis, was the only predictor of a minor index of central apnea and hypopnea (IAH) (p=0.002), greater saturation (p=0.02) and smaller average desaturation of oxygen (p=0.03). Additionally, the use of BB could predict a better quality of life after 6 and 12 months (p=0.002 and 0.001 respectively) and a smaller number admissions in these periods (p=0.001 and p=0.05 respectively). CONCLUSION: The use BB reduced the rate of central sleep apnea in total population, if we compare to literature data. Additionally, the BB improved parameters of quality of sleep and life of patients with heart failure.

FUNDAMENTO: Las apneas del sueño son enfermedades frecuentes en portadores de insuficiencia cardiaca (IC). Una estimación de la era pre betabloqueante (BB) señala hacia una prevalencia del 45 por ciento de apneas centrales en estos pacientes. OBJETIVO: Evaluar la influencia de los BB en la prevalencia de las apneas centrales y su interferencia en la calidad del sueño y de vida de portadores de IC. MÉTODOS: 65 pacientes portadores de IC fueron sometidos a polisonografía diagnóstica. Los resultados de la polisonografía se evaluaron según el empleo o no de BB. El día del examen, los pacientes contestaron el cuestionario de Minnesota para la calidad de vida con IC. Tras 6 y 12 meses de la fecha de la polisonografía, hubo contacto telefónico con todos los pacientes, para la repetición del cuestionario de Minnesota. RESULTADOS: La prevalencia de apnea del sueño (IAH > 15/h) fue de un 46,1 por ciento en la población total, además de la apnea central se identificó en solamente un 18,4 por ciento de los pacientes. El empleo de BB, en análisis multivariado, fue el único predictor de ocurrencia de menor índice de apnea e hipopnea (IAH) central (p=0,002), mayor saturación (p=0,02) y menor desaturación promedio de oxígeno (p=0,03). Además de ello, el empleo de BB fue predictor de mejor calidad de vida tras 6 y 12 meses (p=0,002 y 0,001 respectivamente) y de menor número de hospitalizaciones en estos períodos (p=0,001 y p=0,05 respectivamente). CONCLUSIÓN: El empleo de BB reduzco la incidencia de apnea central en la población total, si lo comparamos con los datos de la literatura. Además de esto, los BB mejoran parámetros de la calidad del sueño y de vida de portadores de IC.

Alleviation of pulmonary hypertension by cardiac resynchronization therapy is associated with improvement in central sleep apnea.

BACKGROUND: Recent studies have demonstrated that cardiac resynchronization therapy (CRT) reduces sleep apnea in heart failure (HF); however, the mechanism of benefit remains unclear. METHODS: Overnight polysomnography (PSG) was performed in consecutive HF patients who were scheduled for CRT implant. Patients with sleep apnea defined by an apnea-hypopnea index (AHI) of >10/hour were recruited and underwent echocardiogram examination at baseline and 3 months after CRT. RESULTS: Among 37 HF patients screened, 20 patients (54%) had sleep apnea and 15 of them consented for the study. After 3 months of CRT, there was a significant improvement in New York Heart Association functional class (3.1+/-0.1 vs 2.1+/-0.1, P<0.01), quality-of-life (QoL) score (62.9+/-3.3 vs 56.1+/-4.5, P=0.02), left ventricular ejection fraction (LVEF, 28.8+/-2.5% vs 38.1+/-2.3%, P<0.01), and reduction in pulmonary artery systolic pressure (PASP, 41.0+/-2.7 vs 28.6+/-2.2 mmHg; P<0.01) compared with baseline. Repeated PSG after CRT demonstrated a reduction in the duration of arterial oxygen desaturation

Induction of central-type sleep apnea by vagus nerve stimulation.

Vagus nerve stimulation (VNS) is an acceptable and effective adjunctive therapy for pharmacoresistant epilepsy. It is generally well tolerated and the most frequent side effects reported include respiratory dysfunction. We report the case of a female patient with intractable epilepsy who was implanted with the device and achieved a significant reduction in the number of her seizures. However, she developed central-type sleep apnea documented polysomnographically. Upon reduction of her VNS parameters, the apnea resolved and her sleep study reverted to normal. To our knowledge, this is the first case reported with polysomnographic evidence of VNS induction of central-type sleep apnea.

Controlled versus assisted mechanical ventilation effects on respiratory motor output in sleeping humans.

Central apneas occur after cessation of mechanical ventilation despite normocapnic conditions. We asked whether this was due to ventilator-induced increases in respiratory rate or VT. Accordingly, we compared the effects of increased VT (135 to 220% of eupneic VT) with and without increased respiratory rate, using controlled and assist control mechanical ventilation, respectively, upon transdiaphragmatic pressure in sleeping humans. Increasing ventilator frequency +1 per minute and VT to 165-200% of baseline eupnea eliminated transdiaphragmatic pressure during controlled mechanical ventilation and prolonged expiratory time (two to four times control) after mechanical ventilation. During and after assist control mechanical ventilation at 135-220% of eupneic VT, transdiaphragmatic pressure was reduced in proportion to the increase in ventilator volume. However, every ventilator cycle was triggered by an active inspiration, and immediately after mechanical ventilation, expiratory time during spontaneous breathing was prolonged less than 20% of that observed after controlled mechanical ventilation at similar VT. We conclude that both increased frequency and VT during mechanical ventilation significantly inhibited respiratory motor output via nonchemical mechanisms. Controlled mechanical ventilation at increased frequency plus moderate elevations in VT reset respiratory rhythm and inhibited respiratory motor output to a much greater extent than did increased VT alone.