Measurement of tumor necrosis factor-alpha, leukotriene B4, and interleukin 8 in the exhaled breath condensate in patients with acute exacerbations of chronic obstructive pulmonary disease.

BACKGROUND: Assessment of airway inflammation in the clinical course of acute exacerbations of chronic obstructive pulmonary disease (AECOPD) may advance our understanding of the pathogenesis and treatment. OBJECTIVES: To assess airway inflammation in patients during the course of AECOPD by serial analyses of their exhaled breath condensates (EBC). METHODS: Twenty-six patients with AECOPD (22 males, mean[SD] percentage predicted forced expiratory volume in one second (FEV(1)) 44.8 [14.3]), 11 with stable COPD, and 14 age and sex-matched healthy controls were studied. Patients with AECOPD were treated with systemic steroid and antibiotic for 7 days. EBC was collected from each patient with AECOPD on Day 5, 14, 30, and 60 post-hospitalization using EcoScreen (VIASYS Healthcare, USA) during tidal breathing over 10 minutes. Concentrations of tumor necrosis factor-alpha (TNF-alpha), leukotriene B4 (LTB4), and interleukin-8 (IL-8) were measured by enzyme-linked immunosorbent assay. RESULTS: The median (IQR) of TNF-alpha level on Day 5 was 5.08 (3.80-6.32) pg/ml, which was lower than on Day 14 (5.84 [4.91-9.14] pg/ml, p = 0.017), Day 30 (6.14 [3.82-7.67] pg/ml, p = 0.045), and Day 60 (5.60 [4.53-8.80] pg/ml, p = 0.009). On Day 60, subjects receiving inhaled corticosteroid (ICS) had a lower level of TNF-alpha than those who were not (4.82 [4.06-5.65] vs 7.66 [5.48-10.9] pg/ml, p = 0.02). EBC LTB4 level did not change significantly during recovery from AECOPD whereas IL-8 was mostly undetectable. CONCLUSIONS: EBC TNF-alpha level was low in patients receiving systemic steroid and antibiotic therapy for AECOPD. These findings suggest a potential role for serial EBC TNF-alpha for non-invasive monitoring of disease activity.

A randomized cross-over study of auto-continuous positive airway pressure versus fixed-continuous positive airway pressure in patients with obstructive sleep apnoea.

BACKGROUND AND OBJECTIVES: To compare the efficacy of auto-CPAP (AutoSet Spirit, ResMed) versus fixed-CPAP (S6 Elite, ResMed) in improving daytime sleepiness, health status, objective compliance and the ultimate treatment preference in patients with severe OSA. METHODS: The study recruited 43 subjects aged 18-65 years with newly diagnosed severe OSA (AHI >30/h). Patients were initially treated with either auto-CPAP or fixed-CPAP for 2 months and then crossed over after a washout period of 1 week for another 2 months. RESULTS: The study was completed by 41 patients. Results are presented as mean (SE). Use of auto-CPAP in the first and the second month was significantly higher than that of fixed-CPAP [129.7 (9.9) and 130.5 (10.7) h vs 115.2 (9.5) and 113.2 (9.4) h, P = 0.04 and 0.01], whereas mean hourly use per night was 4.3 and 4.4 h versus 3.8 and 3.7 h, respectively. The Epworth sleepiness scores improved after 1 month in both treatments (13.4 to 8.5 and 8.2, P < 0.01 for both). The Sleep apnoea quality of life index improved in the first month in both compared with baseline [4.6 (0.2) to 5.0 (0.2) for auto-CPAP and 4.9 (0.2) for fixed-CPAP, P = 0.01 and 0.04, respectively], with no difference between the two treatments. Nine and 30 patients preferred auto-CPAP and fixed-CPAP, respectively, at the end of the trial, whereas 14 and 25 patients would have chosen the same treatments if cost had not been a consideration. CONCLUSIONS: Auto-CPAP and fixed-CPAP were equally effective in improving symptoms and health status in patients with severe OSA. Usage was higher with auto-CPAP, but more patients ultimately chose fixed-CPAP.

Sleep-disordered breathing and continuous positive airway pressure compliance in a group of commercial bus drivers in Hong Kong.

OBJECTIVE AND BACKGROUND: Sleep-disordered breathing may predispose drivers to road traffic accidents. However, CPAP acceptance and compliance among commercial bus drivers is unknown. METHODS: We conducted a sleep questionnaire survey at a bus depot followed by random selection of bus drivers for home sleep study with the mesam iv device. Bus drivers with a respiratory disturbance index (RDI)>or=5/h were invited to have hospital-based polysomnography for confirmation followed by nasal CPAP treatment. RESULTS: Out of 1477 bus drivers, 1016 (971 men) were interviewed with mean (SD) age of 45.3 (7.5) years, BMI 24.9 (3.6) kg/m2, neck circumference 38.9 (3.1) cm and Epworth sleepiness score 4.8 (4.0). Sleepiness at work was reported by 60.9%, snoring>or=3 nights per week 23.9%, witnessed apnoea 3.7% and having fallen asleep during driving by 24%. Among 211 who underwent home sleep study, 85 (40.3%), 55 (26.1%) and 37 (17.5%) had RDI>or=5, >or=10 and >or=15/h respectively. BMI, snoring intensity and neck circumference were the positive independent factors associated with the RDI. Of the 25 drivers who attended polysomnography, nine accepted CPAP prescription with improvement of Epworth sleepiness score, trail B and digit span after 3 months with CPAP usage of 4.5 (1.3) h/night. CONCLUSION: The estimated minimum prevalence rates of sleep-disordered breathing and obstructive sleep apnoea syndrome were 8.4% and 5.4% respectively among the bus drivers. Home CPAP acceptance was low among bus drivers with sleep apnoea but there was significant improvement of subjective sleepiness and cognitive function among those on CPAP treatment.