Effect of CPAP-therapy on bronchial and nasal inflammation in patients affected by obstructive sleep apnea syndrome

BACKGROUND

Obstructive sleep apnea syndrome (OSAS) has been shown to be associated to upper and lower airways inflammation. Continuous positive airway pressure (CPAP) is the elective treatment of OSAS. The aim of the present study was to assess the effect of CPAP-therapy on airway and nasal inflammation.

METHODS

In 13 non-smoking subjects affected by untreated OSAS and in 11 non-smoking normal volunteers, airway inflammation was detected by analyses of the induced sputum. In the OSAS group measurements were repeated after 1, 10 and 60 days of the appropriate CPAP treatment. In addition, in 12 subjects of the OSAS group, nasal inflammation was detected by the analysis of induced nasal secretions at baseline, and after 1, 10 and 60 days of CPAP treatment.

RESULTS

OSAS patients, compared to normal controls, showed at baseline a higher percentage of neutrophils and a lower percentage of macrophages in the induced sputum. One, 10 and 60 days of appropriate CPAP-therapy did not change the cellular profile of the induced sputum. In addition, in the OSAS patients, the high neutrophilic nasal inflammation present under baseline conditions was not significantly modified by CPAP-therapy. Finally, no patients developed airway hyper-responsiveness after CPAP therapy.

CONCLUSIONS

In OSAS subjects, the appropriate CPAP-therapy, while correcting the oxygen desaturation, does not modify the bronchial and nasal inflammatory profile.

Exhaled NO and iNOS expression in sputum cells of healthy, obese and OSA subjects

BACKGROUND

Obstructive sleep apnoea (OSA) is associated with airways inflammation; a key role in this regard seems to be played by nitric oxide (NO). The aim of this study was to measure exhaled NO and expression of its enzyme, the inducible nitric oxide synthase (iNOS) in cells of induced sputum in OSA patients and in obese subjects without sleep apnoea and to correlate these inflammatory markers with severity of OSA.

METHODS

We enrolled 18 obese patients with OSA (10 men, age 48.2 +/- 8.4 years), 15 obese patients without OSA (eight men, age 52.8 +/- 11 years) and 10 healthy subjects (five men, age 42 +/- 4 years). Exhaled NO was measured using a chemiluminescence analyser; iNOS expression was measured in the sputum cells by immunocytochemistry.

RESULTS

Exhaled NO resulted significantly increased in OSA and in obese patients (23.1 +/- 2.1 and 17.9 +/- 2.1 p.p.b.) than in healthy subjects (7.2 +/- 0.6 p.p.b.; P < 0.001). OSA and obese patients showed a higher percentage of neutrophils and a lower percentage of macrophages in the induced sputum compared to healthy subjects. In addition, OSA and obese patients showed higher iNOS expression in neutrophils and in macrophages with respect to healthy subjects. A positive correlation between exhaled NO, iNOS expression and AHI was observed.

CONCLUSIONS

These data confirm the presence of airway inflammation in OSA and in obese patients, and suggest the possible role for NO and iNOS expression in neutrophils of the induced sputum as noninvasive markers to identify and monitor the airway inflammation in these subjects.

Effects of fixed compared to automatic CPAP on sleep in Obstructive Sleep Apnoea Syndrome

BACKGROUND

Automatic CPAP has been developed to improve CPAP efficiency and compliance. Continually matching the effective pressure may be associated to more frequent arousals that could disturb sleep. The aim of the present study was to compare sleep architecture after one month's home therapy with CPAP or with an AutoCPAP device.

METHODS

Twenty OSAS patients (18 M / 2 F) after polysomnographic study with CPAP titration received either an automatic (AutoSet T, ResMed, Sydney, Australia) or a fixed level CPAP machine in a random, single blind fashion for one month. At the end of the home treatment period polysomnography was repeated while CPAP was administered by the same machine used at home.

RESULTS

There was no significant difference between groups in terms of age (50.0 vs 45.5, NS), sex, BMI (38.3 vs 35.1, NS), RDI (45.4 vs 48.0, NS), and CPAP effective level (9.8 vs 10.8, NS). After one month of therapy the correction of sleep respiratory disturbances and of sleep structure was satisfactory in both groups. No difference in any polysomnographic variable or in subjective sleepiness was found at re-evaluation.

CONCLUSIONS

The results of this study demonstrate that on average CPAP administered by a fixed CPAP machine and by the AutoSet T autoCPAP device has similar effects in improving respiratory function during sleep, nocturnal sleep architecture, and subjective daytime sleepiness after a one-month therapy. As autoCPAP devices are more expensive than fixed CPAP machines, their prescription should be considered only after a clear demonstration of an increase in compliance to treatment by these devices.

Low sleep quality and daytime sleepiness in obese patients without obstructive sleep apnoea syndrome

OBJECTIVES

To evaluate sleep quality, sleep-related symptoms, and degree of excessive daytime sleepiness (EDS) in severe obesity, independently of obstructive sleep apnoea syndrome (OSAS).

DESIGN

A cross-sectional study.

SETTING

Primary-care setting.

SUBJECTS, MAIN OUTCOME MEASURES

Anthropometric parameters, respiratory function data and sleep related symptoms were evaluated in 78 severely obese patients (aged 16-75 years) without OSAS and in 40 healthy sex- and age-matched normal weight subjects, who underwent a full-night polysomnography.

RESULTS

Obese patients and control subjects had similar sleep latency and rapid eye movement (REM) latency, but they showed lower percentage of REM (P < 0.01) and sleep efficiency (P < 0.05) than controls. All sleep-related symptoms (observed or reported apnoea, awakenings, choking and unrefreshing sleep) were significantly more frequent in obese patients than in control subjects. Loud snoring was present in 46.7% of the obese patients and in 8.1% of the control individuals (P < 0.01). Excess daytime sleepiness was reported by 34.7% of the obese patients and by 2.7% of the normal weight subjects (P < 0.01). The Epworth Sleepiness Scale (ESS) was higher in the obese group than in the control group (P < 0.01), whereas arousals were not different between the two groups.

CONCLUSIONS

This study clearly shows that severe obesity, even in the absence of OSAS, is associated with sleep-related disorders and EDS. All these alterations may be partly responsible for a lower quality of life, a higher prevalence of medical complications, an increased risk of occupational injury, and both social and family problems characterizing obese patients, independently of the presence of OSAS.