Impact of treating obesity hypoventilation syndrome on body mass index

STUDY OBJECTIVES

To evaluate the impact of positive airway pressure (PAP) therapy on body mass index (BMI) in patients with obesity hypoventilation syndrome (OHS) associated with obstructive sleep apnea (OSA).

METHODS

A systematic review using the following terms: "obesity hypoventilation syndrome" AND "treatment" AND "randomized" using Cochrane Central Register of Controlled Trials, Medline and Web of Science was performed from the first data available until February 10, 2023. The inclusion criteria were: (1) original article; (2) adult OHS with concomitant OSA (apnea-hypopnea index or AHI ≥5 events/h); (3) randomized trial with PAP arm and standard care (control); (4) BMI evaluation at baseline and after the first months. We performed an individual participant data meta-analysis of randomized controlled trials.

RESULTS

Our initial search retrieved 32 articles and 3 randomized studies fulfilled study criteria and were included in the final analysis, leading to a total of 342 participants. Patients were predominantly females (62%) and had OHS associated with at least mild OSA. As compared to baseline, a decrease in BMI was observed at study endpoint but this difference was not different intergroups (-0.50 ± 1.49 and -0.50 ±1.83, in control and PAP groups respectively (p=0.939)). Weight change was not associate with PAP adherence, OSA severity or use of supplemental oxygen.

CONCLUSIONS

In contrast to treatment of eucapnic OSA with PAP that is associated with weight gain, treatment of OSA+OHS patients with or without PAP is associated with weight loss. Future studies are necessary to elucidate the mechanism by which weight loss occurs.

Recent trends in COPD prevalence in Spain: a repeated cross-sectional survey 1997-2007

We aimed to describe changes in the prevalence of chronic obstructive pulmonary disease (COPD) in Spain by means of a repeated cross-sectional design comparing two population-based studies conducted 10 yrs apart. We compared participants from IBERPOC (Estudio epidemiológico de EPOC en España) (n = 4,030), conducted in 1997, with those of EPI-SCAN (Epidemiologic Study of COPD in Spain) (n = 3,802), conducted in 2007. Poorly reversible airflow obstruction compatible with COPD was defined according to the old European Respiratory Society definitions. COPD prevalence in the population between 40 to 69 yrs of age dropped from 9.1% (95% CI 8.1-10.2%) in 1997 to 4.5% (95% CI 2.4-6.6%), a 50.4% decline. The distribution of COPD prevalence by severity also changed from 38.3% mild, 39.7% moderate and 22.0% severe in 1997, to 85.6% mild, 13.0% moderate and 1.4% severe in 2007, and in the 40-69 yr EPI-SCAN sub-sample to 84.3% mild, 15.0% moderate and 0.7% severe. Overall, underdiagnosis was reduced from 78% to 73% (not a significant difference) and undertreatment from 81% to 54% (p<0.05) within this 10-yr frame. The finding of a substantial reduction in the prevalence of COPD in Spain is unexpected, as were the observed changes in the severity distribution, and highlights the difficulties in comparisons between repeated cross-sectional surveys of spirometry in the population.

Apnoeic and obstructive nonapnoeic sleep respiratory events

Obstructive nonapnoeic event (ONE) scoring is shrouded in confusion. This is important in patients with mild disease, in whom precision is crucial. The aims of the present study were: 1) to identify ONEs using oesophageal pressure (OP) (OP-ONEs) and a noninvasive (NI) method (NI-ONEs); 2) to compare both methods of scoring; and 3) to determine the contribution of ONE definitions to clinical findings. Patients with suspected sleep apnoeas (respiratory disturbance index <or=10) during a first polysomnography were subjected to a second with an OP measurement. OP-ONEs and NI-ONEs were defined as an increase in OP or discernible reduction in the amplitude of thoracoabdominal bands with both desaturation and/or arousal. Bland-Altman analysis established agreement. Comparisons were made between OP-ONEs, NI-ONEs and clinical findings. In our sample (n = 90), the addition of an arousal to the NI-ONEs or OP-ONEs with only desaturation increased the number of NI-ONEs by 329 and 362%, respectively. NI-ONEs with arousal and/or desaturation detected 91% of OP-ONEs. The association with sleepiness depended on the incorporation of arousal into the definition of ONEs. In patients with mild disease, the addition of an arousal to ONEs, with only desaturation, markedly increased respiratory disturbance index, with probable therapeutic implications. Scoring respiratory events as apnoea and ONEs is easier and sufficiently accurate.

[Costs of chronic obstructive pulmonary disease in Spain. Estimation from a population-based study]

OBJECTIVE

In the studies carried out to date, the cost of chronic obstructive pulmonary disease (COPD) may have been overestimated due to the inclusion of previously diagnosed patients seeking medical attention for their symptoms. As a result, the severity of the cases included in these studies may have been greater than in an unselected sample of the general population. The aim of the present study was to estimate the direct cost of COPD on the basis of a representative sample of the overall Spanish population between 40 and 69 years of age (from the IBERPOC study).

METHOD

The cost was evaluated retrospectively by means of a questionnaire completed by the 363 patients with COPD from the IBERPOC study with questions referring to the previous year. Standardized spirometry was performed on all the patients by a pneumologist in each of the 7 geographical areas in which the study was carried out.

RESULTS

Hospitalization accounted for the greatest expenditure (41% of total), followed by drug therapy (37%). The cost was euro;98.39 per patient, and euro;909.50 per previously diagnosed patient. The cost per person of severe COPD was more than 3 times that of moderate COPD and more than 7 times that of mild COPD. The estimated annual cost of COPD in Spain was euro;238.82 million (for 1997).

CONCLUSION

The present study, which was the first to estimate the cost of COPD in a representative sample of the general population, found the cost to be lower than in studies analyzing samples of patients with previous diagnoses of COPD. The cost distribution is not in line with recommended health care practices, underlining the need to optimize resources used to monitor and treat the disease, with an emphasis on early diagnosis.

Assessment of thoracoabdominal bands to detect respiratory effort-related arousal

It would be helpful to be able to identify respiratory effort-related arousal (RERA) without needing to measure oesophageal pressure. Thoracoabdominal movements yield an indirect flow measurement from which reduction of amplitude and alteration of the inspiratory flow curve can be detected. The aim of this study was to evaluate the accuracy of using the shape and amplitude of signals from thoracoabdominal bands (inductance plethysmography) to detect RERAs. Altogether, 94 subjects suspected of having sleep apnoea but with an apnoea/hypopnoea index < or = 10 in full polysomnography with oesophageal pressure were studied. A routine polysomnographical analysis was carried out. The polysomnographies were then reanalysed at random to determine which of the identified arousals were due to RERA, as determined either by oesophageal pressure or by induction bands without an oesophageal pressure signal. Altogether, 14,617 arousals were analysed. The sensitivity and specificity to find RERA (arousal by arousal) from bands versus oesophageal pressure were both 94%. The average difference of RERA index between oesophageal pressure and bands was -0.6. The correlation between RERA index determined by oesophageal pressure and bands was 0.98. To evaluate the intra and interobserver agreement, 1183 arousals were additionally analysed. The intraobserver agreement was 91% for RERAs by oesophageal pressure and 80% by bands. The interobserver agreement was 89% by oesophageal pressure and 85% by bands. The thoracoabdominal bands can be used to identify respiratory effort-related arousal (obstructive events not detected by thermistor) with similar efficacy to oesophageal pressure measurement. Since bands are routinely used in most polysomnographies, they can be used as the usual method to detect respiratory effort-related arousal, using a thermistor to evaluate apnoeas and hypopnoeas or as a complement to other methods, such as nasal cannula, which can detect apnoeas, hypopnoeas and respiratory effort-related arousal.

[Respiratory symptoms and diagnosis of COPD in smokers of various types to tobacco. Results from the IBERPOC study]

BACKGROUND

The aim of this study was to investigate the sociodemographic characteristics, smoking habits, the prevalence of respiratory symptoms and chronic obstructive pulmonary disease (COPD) in four groups of smokers: of cigarettes (SCt), of cigars (SCigar), of both (SB), of cigars currently but of cigarettes in the past (SCigarExCt) and of cigarettes currently but of cigars in the past (SCtExCigar).

METHOD

A multicenter epidemiological study enrolling 4,035 subjects aged between 40 and 69 years. One thousand nine hundred sixty-three were non-smokers and 1,146 were current smokers. Among the smokers, 869 were SCt, 37 were SCigar, 97 were SB, 86 were SCigarExCt and 57 were SCtExCigar. We analyzed sociodemographic characteristics, smoking and the prevalence of respiratory symptoms and COPD.

RESULTS

Cigar smokers were usually men, of lower socioeconomic status (p < 0.001) and older than cigarette smokers (p < 0.001), but CO concentrations in expired air were lower in the SCigar group than in the SCt group (5 ppm vs 15.7; p < 0.001). Informants who believed their smoking was not detrimental to their health or to that of second-hand smokers made up 86.5% of the SCigar group and 79.1% of the SCigarExCt group. COPD was diagnosed in 13.2% of the SCt group, in 24.7% of the SB group, and in 12.8% of the SCigarExCt group, in comparison with 4% of the non-smokers (p < 0.001 for all comparisons).

CONCLUSIONS

SCigar are mainly older men with lower educational levels. Their concentrations of CO in expired air are low and they have little awareness of the health risks posed by their habit. SCigar who were once smokers of cigarettes have a higher prevalence of respiratory symptoms and COPD than non-smokers and the same prevalence of COPD as SCt.

Interpretation of quality of life scores from the St George's Respiratory Questionnaire

The aim of the study was to obtain the general population norms for the St. George's Respiratory Questionnaire (SGRQ), a specific questionnaire for respiratory diseases. The IBERPOC project was a cross-sectional study of representative samples of the general population aged between 40-69 yrs. The study sample was composed of 862 individuals. All participants considered as "probable cases" of chronic obstructive pulmonary disease (COPD) (n=460) were eligible to complete the SGRQ and among the rest of the nonprobable COPD participants (n=3,571), 10 individuals from each defined age and sex group were eligible (n=402). Weights were applied to restore general population representativity of the sample. Mean forced expiratory volume in one second (FEV1) predicted was 89.4% (SD=16.5%; range: 16-131%). Chronbach's alpha coefficients were >0.7 in the symptoms, activity and impact scales, and >0.9 in the overall scale. Symptom scale score was significantly higher among males (11.6 versus 7.8; p<0.01) and activity scale score was significantly higher among females (12.2 versus 14.6; p=0.04). In a multiple linear regression model, respiratory diseases (asthma and COPD) and FEV1 % over pred showed the strongest association with the SGRQ total score. Smoking, sex, age and education were independently associated with the total SGRQ score. These results indicate that individuals from the general population presented some of the problems that are important when measuring health-related quality of life in respiratory patients, and provide St George's Respiratory Questionnaire norms, a useful method for interpreting the St George's Respiratory Questionnaire score in a given patient or study samples.

Treatment with continuous positive airway pressure is not effective in patients with sleep apnea but no daytime sleepiness. a randomized, controlled trial

BACKGROUND

The sleep apnea-hypopnea syndrome is defined by a pathologic number of respiratory events during sleep (the apnea-hypopnea index, defined as the number of apnea and hypopnea episodes per hour) and daytime symptoms (mostly, excessive sleepiness). In patients with the sleep apnea syndrome, treatment with continuous positive airway pressure (CPAP) normalizes both the apnea-hypopnea index and diurnal symptoms. However, the effect of CPAP in persons with a pathologic apnea-hypopnea index without daytime sleepiness is unclear.

OBJECTIVE

To investigate the short-term effects of CPAP on quality of life, objective sleepiness, cognitive function, and arterial blood pressure in nonsleepy patients with a pathologic apnea-hypopnea index.

DESIGN

Multicenter randomized, placebo-controlled, parallel-group study.

SETTING

Six teaching hospitals in Spain.

PATIENTS

55 patients with an apnea-hypopnea index of 30 or greater who did not have daytime sleepiness (Epworth Sleepiness Scale score </= 10).

INTERVENTION

Patients were randomly assigned to receive optimal (n = 29) or sham (n = 25) CPAP and were observed for 6 weeks.

MEASUREMENTS

Quality of life, objective sleepiness (Multiple Sleep Latency Test score), cognitive function, and arterial blood pressure.

RESULTS

The intervention and control groups were similar in terms of mean (+/-SE) age (54 +/- 2 vs. 52 +/- 2 years), apnea-hypopnea index (54 +/- 3 vs. 57 +/- 4), Epworth Sleepiness Scale score (7.0 +/- 0.4 vs. 7.0 +/- 0.4) and adherence to CPAP treatment (5.0 +/- 0.4 vs. 4.0 +/- 0.5 hours/d). Other variables, such as quality of life, cognitive function, and arterial blood pressure, were also similar in both groups before treatment. After 6 weeks of CPAP or sham CPAP, none of these variables changed significantly.

CONCLUSION

In patients with an apnea-hypopnea index of 30 or greater and no subjective daytime sleepiness, CPAP does not modify quality of life, objective sleepiness, vigilance, attention, memory, information processing, visuomotor coordination, or arterial blood pressure. Treatment with CPAP is therefore not indicated in nonsleepy patients with a pathologic apnea-hypopnea index.

The obesity hypoventilation syndrome can be treated with noninvasive mechanical ventilation

STUDY OBJECTIVES

To assess the effectiveness of nasal noninvasive mechanical ventilation (NIMV) in patients with obesity hypoventilation syndrome (OHS).

DESIGN

Clinical assay that compares two groups of patients with hypercapnic respiratory failure, one group with OHS and the other group with kyphoscoliosis, in their basal situation and after 4 months of treatment with nocturnal NIMV. Thirty-six patients (22 patients with OHS and 14 patients with kyphoscoliosis) completed the study protocol.

RESULTS

The frequency of symptoms, such as morning headache, morning drowsiness, dyspnea, and leg edema, improved in a statistically significant way in both groups of patients. The sleepiness improved only in the group with OHS. The comparison of frequency of symptoms between both groups of patients after NIMV treatment did not present statistically significant differences. In the resting situation and without nasal ventilation in place, the PO(2) (mean +/- SD) changed from 51 +/- 10 to 64 +/- 11 mm Hg (p < 0.001) and PCO(2) from 58 +/- 10 to 45 +/- 5 mm Hg (p < 0.001) when the patients with OHS were treated with NIMV. In the group of patients with kyphoscoliosis, likewise without nasal ventilation in place, PO(2) changed from 53 +/- 6 to 65 +/- 5 mm Hg (p < 0.001) and PCO(2) from 59 +/- 11 to 45 +/- 4 mm Hg (p < 0.001) with NIMV treatment. When we compared PO(2) and PCO(2) in both groups of patients at the beginning and at the end of NIMV treatment, we did not find statistically significant differences between OHS and kyphoscoliosis.

CONCLUSIONS

NIMV improves the clinical symptoms and the respiratory failure of patients with OHS to a similar degree to that reported for diseases in which its use is completely established, such as kyphoscoliosis. Therefore, NIMV could be an alternative to the treatment of patients with OHS.

Habitually sleepy drivers have a high frequency of automobile crashes associated with respiratory disorders during sleep

Sleepiness is a common cause of traffic crashes with a cost of billions of dollars per year. A recent study has found that 2 to 3% of drivers are habitually sleepy while driving. However, there has not been a controlled study to define the characteristics, driving performance, or automobile crash rate of habitually sleepy drivers. The prevalence of respiratory disorders during sleep, and whether these respiratory disorders contribute to the increased automobile crash frequency, is unknown in habitually sleepy drivers. We interviewed 4,002 randomly selected drivers to define the prevalence of drivers who are habitually sleepy while driving. We studied the habitually sleepy drivers and an age- and sex-matched control group of drivers. These studies included reporting of daytime sleepiness, automobile crashes, driving performance and sleep studies. Of the 4, 002 drivers interviewed, 145 (3.6%, confidence interval [CI] = 3.1 to 4.3) were habitually sleepy while driving. The habitually sleepy drivers reported a significantly higher frequency of auto crashes than control subjects (the adjusted odds ratio [OR] was 13.3, CI = 4. 1 to 43). The habitually sleepy drivers had a significantly higher prevalence of respiratory sleep disorders than control subjects. For a total respiratory events index (apneas, hypopneas, and other respiratory effort-related arousals) >/= 15 the adjusted OR was 6.0, CI = 1.1 to 32. In the habitually sleepy drivers group, the frequency of sleep apnea (apnea-hypopnea index) between subjects with or without auto crashes was not statistically different. However, if we consider total respiratory events index, this frequency of respiratory sleep disorders was significantly higher in subjects with automobile crashes (the adjusted OR for a total respiratory event index >/= 15 was 8.5, CI = 1.2 to 59). Habitually sleepy drivers are a large group of drivers (1 of 30 drivers) who are involved in several fold more automobile crashes than control subjects. As these excess auto crashes can be explained in part by the presence of respiratory disorders during sleep, which are treatable, many automobile crashes in these sleepy drivers may be preventable. Our findings suggest that asking about excessive sleepiness while driving may better predict which subjects with breathing disorders during sleep have crashes than asking about overall sleepiness.

Geographic variations in prevalence and underdiagnosis of COPD: results of the IBERPOC multicentre epidemiological study

OBJECTIVES

To ascertain the prevalence, diagnostic level, and treatment of COPD in Spain through a multicenter study comprising seven different geographic areas.

DESIGN AND PARTICIPANTS

This is an epidemiologic, multicenter, population-based study conducted in seven areas of Spain. A total of 4,035 men and women (age range, 40 to 69 years) who were randomly selected from a target population of 236,412 subjects participated in the study.

INTERVENTIONS

Eligible subjects answered the European Commission for Steel and Coal questionnaire. Spirometry was performed, followed by a bronchodilator test when bronchial obstruction was present.

RESULTS

The prevalence of COPD was 9.1% (95% confidence interval [CI], 8.1 to 10.2%), 15% in smokers (95% CI, 12.8 to 17.1%), 12.8% in ex-smokers (95% CI, 10.7 to 14.8%), and 4.1% in nonsmokers (95% CI, 3.3 to 5.1%). The prevalence in men was 14.3% (95% CI, 12.8 to 15. 9%) and 3.9% in women (95% CI, 3.1 to 4.8%). Marked differences were observed between sexes in smoking; the percentage of nonsmokers was 23% in men and 76.3% in women (p<0.0001). The prevalence of COPD varied among the areas, ranging from 4.9% (95% CI, 3.2 to 7.0%) in the area of the lowest prevalence to 18% (95% CI, 14.8 to 21.2%) in the area of the highest. There was no previous diagnosis of COPD in 78.2% of cases (284 of 363). Only 49.3% of patients with severe COPD, 11.8% of patients with moderate COPD, and 10% of patients with mild COPD were receiving some kind of treatment for COPD. Multivariate analysis showed that individuals had a higher probability of having received a previous diagnosis of COPD if they lived in urban areas, were of male gender, were > 60 years old, had higher educational levels, had > 15 pack-year smoking history, or had symptoms of chronic bronchitis.

CONCLUSIONS

COPD is a very frequent disease in Spain, and presents significant geographic variations and a very low level of previous diagnosis and treatment, even in the most advanced cases.

[Epidemiological study of chronic obstructive pulmonary disease in Spain (IBERPOC): prevalence of chronic respiratory symptoms and airflow limitation]

The prevalence of chronic respiratory symptoms and chronic airflow limitation (CAFL) was determined in a multicentric epidemiological study carried out in seven different areas of Spain. Based on a target population of 236,412 persons, a random census sample of 4,035 individuals between 40 and 69 years of age was chosen. Subjects answered several questionnaires and performed spirometric tests followed by a bronchodilation test if bronchial obstruction was detected. Respiratory symptoms were reported by 48% of the population (95% CI: 46.4-49.5%) with greater frequency of symptoms among men than women (55.2% versus 41%, p < 0.001). The following levels of prevalence of chronic symptoms were found: cough, 13.5% (95% CI: 12.5-14.6%); expectoration, 10.7% (95% CI: 9.7-11.6%); dyspnea after one flight of stairs, 10.4% (95% CI: 9.5-11.4%); and wheezing, 40.2% (95% CI: 38.7-41.7%). The prevalence of chronic bronchitis (CB) was 4.8% (95% CI: 4.1-5.4%) and was more frequent among men than among women (8.3% and 1.4%, respectively; p < 0.001). Asthma had been diagnosed previously in 4.9% (95% CI: 4.2-5.5%), more often in women than in men (5.8% and 3.8%, respectively; p < 0.003). CAFL was found in 10.6% (95% CI: 9.6-11.5%), 15.8% in men and 5.5% in women (p < 0.001). All respiratory symptoms except asthma were more frequent among smokers than among ex-smokers, and in turn were more common among ex-smokers than non-smokers. The frequency of symptoms increased in accordance with accumulated smoking. The prevalence of CB and CAFL was vastly different from one region to another. Multivariate analysis showed that factors associated independently with the appearance of CB were smoking, age over 60 years, male sex and having worked in industry. In conclusion, respiratory symptoms, including CB and CAFL, are common in the Spanish population. Smoking and amount of smoking are directly related to the frequency of such symptoms. Substantial differences were found in the prevalence of CB and CAFL among the regions where the study was performed.

[Epidemiological study of chronic obstructive pulmonary disease in Spain (IBERPOC): recruitment and field work]

Chronic obstructive pulmonary disease (COPD) is a large-scale social and health problem. Because prevalence studies have been performed only in certain areas of Spain, the Spanish Society of Pneumology and Chest Surgery initiated the IBERPOC study with the aim of determining the prevalence of COPD in several parts of the country. IBERPOC is a multicenter, population-based epidemiological study in which subjects have been selected randomly. Seven full-time pneumologists work full-time in seven different areas of Spain. A study of this nature involves a series of difficulties that should be taken into account at the time of planning studies of a similar nature. After 5,827 attempts to reach subjects, a total of 4,967 useful contacts were made, to provide 97.3% of the 5,104 contacts expected. Of those 4,967 useful contacts, 4,035 subjects completed interviews. Among the 932 refusals, 882 (94.6%) agreed to answer a short telephone questionnaire. The field work took 13 months to complete, 30% more time than had been anticipated. The rates at which subjects could not be traced differed from one zone to another, ranging between 5% and 30%; higher rates were attributable to the absence of telephone data in the corresponding census report. In one zone, the dispersion of the census population over a very large area supposed greater difficulty and delay in carrying out the study. In conclusion, the rate of participation and the time required for recruitment can be considered satisfactory. The performance of field work by trained, full-time pneumologists has been essential to the development and quality of the study. Similar epidemiological studies should consider problems derived from the lack of adequate census data, as well as to avoid defining areas of extreme population dispersion in order to facilitate field work.

[Usefulness of transbronchial punction and mediastinoscopy in mediastinal nodal staging of non-microcytic bronchogenic carcinoma. Preliminary study]

Preliminary study to compare the sensitivity and specificity of transbronchial needle aspiration (TBNA) and mediastinoscopy/anterior mediastinotomy (MED/AMED) and/or thoracotomy for staging of mediastinal nodes in non-small cell carcinoma. To determine the sensitivity and specificity of computerized tomography (CT) as a screening technique. Thirty-three patients with non-small cell carcinoma but no remote metastasis and good lung function were evaluated. A chest CT scan was performed before bronchoscopy in 27 patients and before surgery in the others. Nodular areas considered diseased based on CT images were staged by TBNA. When CT images were not available before bronchoscopy. TBNA for staging was performed in the subcarinal region. Results by TBNA were compared with those obtained by MED/AMED and/or thoracotomy. The prevalence of metastatic nodular disease was 47%. CT detected enlarged mediastinal nodes in 24 patients; the images were considered normal in 9 patients. Sensitivity and specificity of CT was 93% and 54%, respectively, with a positive predictive value (PPV) of 68% and negative predictive value (NPV) of 87.5%. The sensitivity and specificity of MED/AMED were 73% and 100%, respectively; PPV was 100% and NPV was 75%. The sensitivity and specificity of TBNA were 36% and 92%, respectively; PPV was 83% and NPV was 57%. The pneumothorax with pleural empyema suffered by one patient after MED could have been avoided, given that the earlier TBNA was positive. TBNA is a safe, useful technique for staging nodes in non-small cell carcinoma. Although the sensitivity of TBNA is lower than that of MED, regions that are difficult to reach with the latter technique can be sampled by TBNA. Furthermore, MED can be rendered unnecessary by positive TBNA results. CT imaging of the chest is sensitive but its specificity is low for detecting ganglial metastasis.

Noninvasive positive pressure ventilation and not oxygen may prevent overt ventilatory failure in patients with chest wall diseases

Some patients with chest wall diseases (CWD) without respiratory failure manifest important alterations in nocturnal gas exchange, as a previous stage to the future development of daytime respiratory failure. The purpose of this study was to evaluate the efficacy of nasal intermittent positive pressure ventilation (NIPPV) during sleep in a group of obese patients and in another group with restrictive thoracic diseases (RTD), comparing the results with those obtained from conventional nocturnal oxygen therapy. From a total of 42 patients with CWD free of daytime respiratory failure, 27 (64%) were considered nocturnal oxygen desaturators without sleep apnea and were included in the study. The study protocol was completed by 21 of these patients. After 2 weeks of treatment, symptoms of dyspnea, morning headaches, and morning obnubilation improved significantly (p<0.05) in both groups of patients after NIPPV but not with oxygen. Baseline daytime PaO2 was 68+/-7 mm Hg in the obese group of patients and 73+/-11 mm Hg in the RTD group. It improved significantly with NIPPV to 73+/-5 mm Hg in obese patients (p<0.05) and to 77+/-12 mm Hg in the RTD group (p<0.05) but did not change with oxygen (68+/-8 mm Hg in the obese group and 73+/-12 mm Hg in the RTD group). Both treatments improved oxygen saturation during sleep, but oxygenation tends to be higher with oxygen than with NIPPV. Only NIPPV was able to normalize the baseline nocturnal alveolar hypoventilation. From the 21 patients treated, 19 decided to continue with long-term NIPPV, one with oxygen, and one refused treatment. We conclude that in patients with CWD who manifest nighttime oxygen desaturation and hypoventilation, early initiation of NIPPV is preferable to supplemental oxygen. Our results also suggest that NIPPV initiated before overt ventilatory failure could prevent its onset.

A first case of progressive supranuclear palsy and pre-clinical REM sleep behavior disorder presenting as inhibition of speech during wakefulness and somniloquy with phasic muscle twitching during REM sleep

It is known that a pre-clinical stage may precede the full-fledged form of REM sleep behavior disorder (RBD) and that somniloquy, yelling and limb jerking may be prodromes of RBD. In the present paper, the case of a woman exhibiting both somniloquy and daytime inhibition of speech is discussed. Clinical and polysomnographic findings were consistent with the dual diagnosis of progressive supranuclear palsy (PSP) and preclinical RBD. Severe akinesia and supranuclear palsy of phonation are postulated as likely mechanisms for the inhibition of speech, whereas the overexcitation of the motor system by the RBD process seemed to account for the sleeptalking episodes.