Although high-intensity noninvasive positive pressure ventilation (HI-NPPV) is superior to low-intensity noninvasive positive pressure ventilation (LI-NPPV) in controlling nocturnal hypoventilation in stable hypercapnic patients with COPD, it produces higher amounts of air leakage, which, in turn, could impair sleep quality. Therefore, the present study assessed the difference in sleep quality during HI-NPPV and LI-NPPV.A randomized, controlled, crossover trial comparing sleep quality during HI-NPPV (mean inspiratory positive airway pressure 29 ± 4 mbar) and LI-NPPV (mean inspiratory positive airway pressure 14 mbar) was performed in 17 stable hypercapnic patients with COPD who were already familiar with HI-NPPV.Thirteen patients (mean FEV(1) 27% ± 11% predicted) completed the trial; four patients refused to sleep under LI-NPPV. There was no significant difference in sleep quality between the treatment groups (all P > .05), with a mean difference of -3.0% (95% CI, -10.0 to 3.9; P = .36) in the primary outcome, namely non-rapid eye movement sleep stages 3 and 4. However, nocturnal Paco(2) was lower during HI-NPPV compared with LI-NPPV, with a mean difference of -6.4 mm Hg (95% CI, -10.9 to -1.8; P = .01).In patients with COPD, high inspiratory pressures used with long-term HI-NPPV produce acceptable sleep quality that is no worse than that produced by lower inspiratory pressures, which are more traditionally applied in conjunction with LI-NPPV. In addition, higher pressures are more successful in maintaining sufficient alveolar ventilation compared with low pressures. Thus, HI-NPPV is a very promising new approach, but still requires large, longer-term trials to determine the impact on outcomes such as exacerbation rates and longevity. TRIAL REGISTRY: German Clinical Trials Register (DRKS); No.: DRKS00000520; URL: www.drks.de.

There has been marked expansion in the literature and practice of pediatric sleep medicine; however, no recent evidence-based practice parameters have been reported. These practice parameters are the first of 2 papers that assess indications for polysomnography in children. This paper addresses indications for polysomnography in children with suspected sleep related breathing disorders. These recommendations were reviewed and approved by the Board of Directors of the American Academy of Sleep Medicine.A systematic review of the literature was performed, and the American Academy of Neurology grading system was used to assess the quality of evidence. RECOMMENDATIONS FOR PSG USE: 1. Polysomnography in children should be performed and interpreted in accordance with the recommendations of the AASM Manual for the Scoring of Sleep and Associated Events. (Standard) 2. Polysomnography is indicated when the clinical assessment suggests the diagnosis of obstructive sleep apnea syndrome (OSAS) in children. (Standard) 3. Children with mild OSAS preoperatively should have clinical evaluation following adenotonsillectomy to assess for residual symptoms. If there are residual symptoms of OSAS, polysomnography should be performed. (Standard) 4. Polysomnography is indicated following adenotonsillectomy to assess for residual OSAS in children with preoperative evidence for moderate to severe OSAS, obesity, craniofacial anomalies that obstruct the upper airway, and neurologic disorders (e.g., Down syndrome, Prader-Willi syndrome, and myelomeningocele). (Standard) 5. Polysomnography is indicated for positive airway pressure (PAP) titration in children with obstructive sleep apnea syndrome. (Standard) 6. Polysomnography is indicated when the clinical assessment suggests the diagnosis of congenital central alveolar hypoventilation syndrome or sleep related hypoventilation due to neuromuscular disorders or chest wall deformities. It is indicated in selected cases of primary sleep apnea of infancy. (Guideline) 7. Polysomnography is indicated when there is clinical evidence of a sleep related breathing disorder in infants who have experienced an apparent life-threatening event (ALTE). (Guideline) 8. Polysomnography is indicated in children being considered for adenotonsillectomy to treat obstructive sleep apnea syndrome. (Guideline) 9. Follow-up PSG in children on chronic PAP support is indicated to determine whether pressure requirements have changed as a result of the child's growth and development, if symptoms recur while on PAP, or if additional or alternate treatment is instituted. (Guideline) 10. Polysomnography is indicated after treatment of children for OSAS with rapid maxillary expansion to assess for the level of residual disease and to determine whether additional treatment is necessary. (Option) 11. Children with OSAS treated with an oral appliance should have clinical follow-up and polysomnography to assess response to treatment. (Option) 12. Polysomnography is indicated for noninvasive positive pressure ventilation (NIPPV) titration in children with other sleep related breathing disorders. (Option) 13. Children treated with mechanical ventilation may benefit from periodic evaluation with polysomnography to adjust ventilator settings. (Option) 14. Children treated with tracheostomy for sleep related breathing disorders benefit from polysomnography as part of the evaluation prior to decannulation. These children should be followed clinically after decannulation to assess for recurrence of symptoms of sleep related breathing disorders. (Option) 15. Polysomnography is indicated in the following respiratory disorders only if there is a clinical suspicion for an accompanying sleep related breathing disorder: chronic asthma, cystic fibrosis, pulmonary hypertension, bronchopulmonary dysplasia, or chest wall abnormality such as kyphoscoliosis. (Option) RECOMMENDATIONS AGAINST PSG USE: 16. Nap (abbreviated) polysomnography is not recommended for the evaluation of obstructive sleep apnea syndrome in children. (Option) 17. Children considered for treatment with supplemental oxygen do not routinely require polysomnography for management of oxygen therapy. (Option)Current evidence in the field of pediatric sleep medicine indicates that PSG has clinical utility in the diagnosis and management of sleep related breathing disorders. The accurate diagnosis of SRBD in the pediatric population is best accomplished by integration of polysomnographic findings with clinical evaluation.

A wide variety of mechanisms can lead to the hypoventilation associated with various medical disorders, including derangements in central ventilatory control, mechanical impediments to breathing, and abnormalities in gas exchange leading to increased dead space ventilation. The pathogenesis of hypercapnia in obesity hypoventilation syndrome remains somewhat obscure, although in many patients comorbid obstructive sleep apnea appears to play an important role. Hypoventilation in neurologic or neuromuscular disorders is primarily explained by weakness of respiratory muscles, although some central nervous system diseases may affect control of breathing. In other chest wall disorders, obstructive airways disease, and cystic fibrosis, much of the pathogenesis is explained by mechanical impediments to breathing, but an element of increased dead space ventilation also often occurs. Central alveolar hypoventilation syndrome involves a genetically determined defect in central respiratory control. Treatment in all of these disorders involves coordinated management of the primary disorder (when possible) and, increasingly, the use of noninvasive positive pressure ventilation.

To summarize the experience in diagnosis and treatment of pulmonary hypertension caused by sleep hypoventilation.The clinical data of 4 patients in a family with pulmonary hypertension caused by sleep hypoventilation, full brothers and sisters, 2 (Cases 1 and 2) being treated presently and 2 (Cases 3 and 4) being deceased and traced by family medical history, were retrospectively analyzed.Three of the 4 cases (cases 1, 3, and 4) were misdiagnosed as with cor pulmonale combined with pulmonary hypertension, and one case (case 2) was misdiagnosed as with primary pulmonary hypertension. Polysomnography (PSG) revealed alveolar hypoventilation-induced long period of oxygen desaturation at sleep in Cases 1 and 2, thus confirming the diagnosis. Pulmonary function test showed that the percentage of maximum inspiratory pressure (PImax) in predicted value (51.5% and 20.9%) and the maximum expiratory pressure (PEmax) in predicted value (51.3% and 29.6%) decreased, the percentage of mouth occlusion pressure (P0.1) in predicted value (141% and 133%) compensatively increased, and the respiratory muscle strength decreased in Cases 1 and 2, which suggested that there was neuromuscular disorder in these patients. Treated by noninvasive ventilation the symptoms of these 2 patients were improved and they were discharge at last. Subsequently, they were treated by long-term night noninvasive ventilation at home, and returned to normal work and life. During the follow-up for 22 and 12 months respectively after discharge, PSG showed that the alveolar hypoventilation-induced long period oxygen desaturation at sleep had been greatly improved, and echocardiogram showed that the pulmonary pressure was greatly decreased.For the patients with unexplained pulmonary hypertension, PSG monitoring and pulmonary function tests such as PImax, PEmax, and P0.1 help determine the etiology, and long-term night noninvasive ventilation at home can improve the outcome of sleep hypoventilation-induced pulmonary hypertension.

Air leaks often result in alveolar hypoventilation in mechanically ventilated patients with neuromuscular disease. The primary objective of this study was to assess the feasibility, efficacy and tolerance of a ventilator equipped with an automated air-leak compensation system in a clinical situation. Fourteen neuromuscular patients with nocturnal air leaks during home ventilation were included in a prospective randomised crossover study. A modified VS Ultra ventilator was studied during two consecutive nights and patients were randomly ventilated with and without a leak-compensation system, respectively. Tolerance, minute ventilation, blood gas values, sleep parameters, and nocturnal oxygen saturation were assessed. Leak compensation significantly increased the mean inspiratory and expiratory tidal volumes (731+/-312 vs. 1094+/-432 ml [p=0.002] and 329+/-130 vs. 496+/-388 ml [p=0.006], respectively) and inspiratory and expiratory flows (51.7+/-8.2 vs. 61.8+/-12.4 l/min [p=0.016] and 63.3+/-26.2 vs. 83.3+/-37.8 l/min [p=0.013], respectively). The system acted by increasing both inspiratory time (from 1355+/-230 to 1527+/-159 ms, p=0.038) and inspiratory pressure (from 14.0+/-2.8 to 18.3+/-3.4 cm H(2)O, p=0.002). Leak compensation improved arterial PCO(2) (6.18+/-0.9 vs. 5.21+/-1.0 kPa, p=0.004), slow-wave-sleep latency (119+/-69 vs. 87+/-35 min, p=0.04), and tolerance. Air-leak compensation is feasible and may produce beneficial effects in neuromuscular patients. The automatic air-leak compensation system tested here should be evaluated in long-term efficacy and tolerance studies and compared to other ventilation modes capable of compensating for leaks, such as pressure support.

Prader-Willi syndrome (PWS), with a prevalence of 60:1.000.000, results from the loss of paternal chromosome 15, being 56% due to deletion, 24% due to uniparental maternal disomy, and 18% from methylation, an epigenetic phenomenon. The clinical picture begins with extreme muscular hypotonia, which makes it difficult to feed the child in the first year. As the hypotonia improves, usually in the first two years, around the 4th year of life, an insatiable appetite leads these children to an extreme obesity, with alveolar hypoventilation which endangers their lives. So, paradoxically, PWS threatens the lives of the patients, through inanition in a first phase and, afterwards, through excessive weight gain. The use of growth hormone (hrGH) in these children has a primary goal to change the body composition and improve the physical activity and the quality of life. On the other hand, many PWS patients are indeed GH deficient, and an improvement in the height SDS occurs with treatment. We have to be careful, however. When starting a PWS treatment with a patient on hrGH, a careful evaluation of sleep apnoea (polysomnography) as well as a careful examination of the airways is extremely mandatory, since the treatment may compromise the respiratory pattern of some patients.

Studies examining pulmonary gas exchange during exercise have primarily focused on young healthy men, whereas the female response to exercise has received limited attention. Evidence is accumulating that the response of the lungs, airways, and (or) respiratory muscles to exercise is less than ideal and this may significantly compromise oxygen transport in certain groups of otherwise healthy, fit, active, male subjects. Women may be even more susceptible to exercise-induced pulmonary limitations than height-matched men, by virtue of their smaller lung volumes, lower maximal expiratory flow rates, and smaller diffusion surface areas. We have recently shown that exercise-induced arterial hypoxaemia (EIAH) is more prevalent and occurs at relatively lower fitness levels in females than in males. Despite this finding, few physiologically based mechanisms have been identified to explain why women may be more susceptible to EIAH than men. Potential mechanisms of EIAH include relative alveolar hypoventilation, ventilation-perfusion inequality, and diffusion limitation. Whether these mechanisms are different between sexes remains controversial. The primary purpose of this review is to summarize the available data on EIAH in women and to discuss potential sex-based mechanisms for gas exchange impairment. Furthermore, we discuss unresolved questions dealing with pulmonary system limitations during exercise in women.

Chronic alveolar hypoventilation is a common complication of many neuromuscular and chest wall disorders. Long-term nocturnal mechanical ventilation is increasingly used to treat it.To examine the efficacy of nocturnal mechanical ventilation in relieving hypoventilation related symptoms and in prolonging survival in people with neuromuscular or chest wall disorders.We searched the Cochrane Neuromuscular Disease Group Trials Register, MEDLINE (from January 1966 to June 2006), and EMBASE (from January 1980 to June 2006) for randomised trials and contacted authors of trials and other experts in the field.We searched for quasi-randomised or randomised controlled trials of participants with neuromuscular or chest wall disorder-related stable chronic hypoventilation of all ages and all degrees of severity, receiving any type and any mode of nocturnal mechanical ventilation. The primary outcome measure was short-term and long-term reversal of hypoventilation related clinical symptoms and secondary outcomes were unplanned hospital admission, one year mortality, short-term and long-term reversal of daytime hypercapnia, improvement of lung function and sleep breathing disorders.We identified eight randomised trials.The eight eligible trials included a total of 144 participants. The relative risk of 'no improvement of hypoventilation related clinical symptoms' in the short-term following nocturnal mechanical ventilation was available in only one trial with 10 participants and was not significant, 0.09 (95% confidence interval (CI) 0.01 to 1.31). The relative risk of 'no reversal of daytime hypercapnia' in the short-term following nocturnal ventilation was significant and favoured treatment, 0.37 (95% CI 0.20 to 0.65). The weighted mean difference of nocturnal mean oxygen saturation was 5.45% (95% CI 1.47 to 9.44) more improvement in participants treated with nocturnal mechanical ventilation. For most of the outcome measures there was no significant long-term difference between nocturnal mechanical ventilation and no ventilation. However, the estimated risk of death based on three studies was reduced following nocturnal ventilation, 0.62 (95% CI 0.42 to 0.91). There was considerable and significant heterogeneity between the trials possibly related to differences between the study populations. Most of the secondary outcomes were not assessed in the eligible trials. Data from two crossover trials suggested no evidence for a difference in reversal of daytime hypercapnia and sleep study parameters between volume-cycled and pressure-cycled ventilation. No data could be summarised for the comparisons between invasive and non-invasive mechanical ventilation or between intermittent positive pressure and negative pressure ventilation.Current evidence about the therapeutic benefit of mechanical ventilation is weak, but consistent, suggesting alleviation of the symptoms of chronic hypoventilation in the short-term. In three small studies survival was prolonged mainly in participants with motor neuron diseases. With the exception of motor neuron disease, further larger randomised trials are needed to confirm long-term beneficial effects of nocturnal mechanical ventilation on quality of life, morbidity and mortality, to assess its cost-benefit ratio in neuromuscular and chest wall diseases and to compare the different types and modes of ventilation.

The association of primary alveolar hypoventilation (PAH) and chromosomic diseases has not been described previously. A 19 year-old man with Fraccaro's syndrome (XXXXY karyotype) was admitted to evaluate chronic hypercapnic respiratory failure, pulmonary arterial hypertension and cor pulmonale. PAH was diagnosed. As effective treatment, such as non-invasive positive pressure ventilation (NIPPV), is available for this disorder we should intensify the search for PAH in patients with chromosome disease.