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Background: The mechanisms underlying sleep-related hypoventilation in patients with coexisting COPD and obstructive sleep apnoea (OSA), an overlap syndrome, are incompletely understood. We compared neural respiratory drive expressed as diaphragm electromyogram (EMGdi) and ventilation during stage 2 sleep in patients with COPD alone and patients with overlap syndrome.Methods: EMGdi and airflow were recorded during full polysomnography in 14 healthy subjects, 14 patients with OSA and 39 consecutive patients with COPD. The ratio of tidal volume to EMGdi was measured to indirectly assess upper airway resistance.Results: Thirty-five patients with COPD, 12 healthy subjects and 14 patients with OSA completed the study. Of 35 patients with COPD, 19 had COPD alone (FEV1 38.5%±16.3%) whereas 16 had an overlap syndrome (FEV1 47.5±16.2%, AHI 20.5±14.1 events/hour). Ventilation (VE) was lower during stage 2 sleep than wakefulness in both patients with COPD alone (8.6±2.0 to 6.5±1.5 L/min, p<0.001) and those with overlap syndrome (8.3±2.0 to 6.1±1.8 L/min). Neural respiratory drive from wakefulness to sleep decreased significantly for patients with COPD alone (29.5±13.3% to 23.0±8.9% of maximal, p<0.01) but it changed little in those with overlap syndrome. The ratio of tidal volume to EMGdi was unchanged from wakefulness to sleep in patients with COPD alone and healthy subjects but was significantly reduced in patients with OSA or overlap syndrome (p<0.05).Conclusions: Stage 2 sleep-related hypoventilation in COPD alone is due to reduction of neural respiratory drive, but in overlap syndrome it is due to increased upper airway resistance. [ABSTRACT FROM AUTHOR]

CO 2 inhalation has been previously reported as a treatment for central sleep apnea both when associated with heart failure or where the cause is unknown. Here, we evaluated a novel CO 2 supply system using a novel open mask capable of comfortably delivering a constantly inspired fraction of CO 2 ([Formula: see text]) during sleep. We recruited 18 patients with central sleep apnea (13 patients with cardiac disease, and 5 patients idiopathic) diagnosed by diaphragm electromyogram (EMG) recordings made during overnight full polysomnography (PSG) ( night 1 ). In each case, the optimal [Formula: see text] was determined by an overnight manual titration with PSG ( night 2 ). Titration commenced at 1% CO 2 and increased by 0.2% increments until central sleep apnea (CSA) disappeared. Patients were then treated on the third night ( night 3 ) with the lowest therapeutically effective concentration of CO 2 derived from night 2 . Comparing night 1 and night 3 , both apnea-hypopnea index (AHI; 31 ± 14 vs. 6 ± 3 events/h, P < 0.01) and arousal index (22 ± 8 vs. 15 ± 8 events/h, P < 0.01) were significantly improved during CO 2 treatment. Sleep efficiency improved from 71 ± 18 to 80 ± 11%, P < 0.05, and sleep latency was shorter (23 ± 18 vs. 10 ± 10 min, P < 0.01). Heart rate was not different between night 1 and night 3 . Our data confirm the feasibility of our CO 2 delivery system and indicate that individually titrated CO 2 supplementation with a novel device including a special open mask can reduce sleep disordered breathing severity and improve sleep quality. Randomized controlled studies should now be undertaken to assess therapeutic benefit for patients with CSA. NEW & NOTEWORTHY A novel device using a special mask was developed and proved that CO 2 therapy using the device could eliminate central sleep apnea (CSA) events and improve sleep quality including reducing arousal index in patients with heart failure. The device would become a useful clinical treatment for heart failure patients with CSA.

This study was designed to use iTRAQ technology coupled with 2D LC-MS/MS to study the comparative proteomics of different processing technology for pilose antler. 1015 proteins were identified with 2D LC combined with MOLDI TOF/TOF mass spectrometry. Comparative analysis with Protein Pilot (Version 4.5) revealed that 87 proteins were changed (P ≤ 0.05, the ratio of > 1.50 or < 0.60 as the threshold selection of difference proteins), of which 24 were up regulated and 33 were down regulated in the traditional frying process (TFP) compared with the fresh pilose antler (P ≤ 0.05). 7 significant different proteins (P ≤ 0.001), most of these significantly changed proteins were found to be involved in calcium ion binding and ATP binding associated with human healthy. Freeze drying with protective agent (FDP) (Trehalose) can improve the content of significantly different proteins (P ≤ 0.001) including Collagen alpha-1 (XII) chain (COL12A1) and Collagen alpha-1 (II) chain (COL2A1). The significant function involves in platelets activating, maintenance of spermatogonium, and disorder expression in tumor cells. The functional annotation by Hierarchical clustering and GO (gene ontology) showed that the main molecule functions of the proteins significantly changed in these processes were involved in binding (52.7%), catalytic (25.3%), structural molecule and transporter (6.6%).

Objective: To compare the continuous positive airway pressure (CPAP) of automatic titration with that of manual titration., Methods: A total of 58 patients with obstructive sleep apnea and hypopnea syndrome (OSAHS) diagnosed by overnight polysomnography at sleep center of First Affiliated Hospital, Guangzhou Medical University were studied between December 2010 and December 2012. Manual titration was performed under full polysmnography and auto-titration at home for 3-7 nights., Results: There were 52 males and 6 females with an age range of (48 ± 11) years. CPAP pressure titrated by automatic device (10.0 ± 2.2) cm H2O (1 cm H2O = 0.098 kPa) was significantly higher than that titrated manually (7.5 ± 1.5) cm H2O (P = 0.000). Apnea-hyponea index decreased significantly from (54.0 ± 21.0) events/h pre-treatment to (3.8 ± 2.5) events/h post-treatment under manual titration (P < 0.01)., Conclusions: CPAP pressure titrated by automatic device is usually higher than that titrated manually. Manual titration should be performed if a patient can not tolerate the CPAP pressure titrated by an automatic device.

Objective: Assessment of neural respiratory drive is useful for diagnosis of dyspnea and respiratory failure with unknown causes. The purpose of the study was to compare the sensitivity of trandiaphragmatic pressure (Pdi) and diaphragm electromyogram (EMGdi) in assessment of neural respiratory drive., Methods: A combined catheter with 10 electrodes and 2 balloons was used to record EMGdi and Pdi during CO2 rebreathing. Three different inspiratory maneuvers-inspiration from functional residual capacity to total lung capacity (TLC), deep inspiration from functional residual capacity against closed airway (MIP), and short sharp inspiration through the nose (Sniff) were performed. Ten healthy subjects [male 4 and female 6; age (26 ± 4) years] were studied., Results: Linear relationship between EMGdi and end-tidal CO2 (r = 0.83-0.98, all P < 0.01) was better than that between Pdi and end-tidal CO2 (r = 0.48-0.96, all P < 0.01) during CO2 rebreathing, Z = -2.731, P < 0.05. The slope of linear relation between EMGdi and end-tidal CO2 (16.3-32.5) was significantly higher than that between Pdi and end-tidal CO2 (0.4-11.1), Z = -3.780, P < 0.01. The maximal EMGdi derived from TLC maneuver (211 ± 48) µV was larger than those from the MIP maneuver (161 ± 48) µV and the Sniff maneuver (145 ± 37) µV, F = 5.931, P < 0.05, whereas the maximal Pdi derived from TLC maneuver (58 ± 27) cm H2O (1 cm H2O = 0.098 kPa) was significantly lower than those from the MIP maneuver (92 ± 32) cm H2O and the Sniff maneuver (95 ± 27) cm H2O, F = 5.155, P < 0.05., Conclusion: EMGdi is more sensitive than Pdi in the assessment of neural respiratory drive.

Objective: To explore the effects of neural respiratory drive on ventilation in patients with chronic obstructive pulmonary disease (COPD) during sleep., Methods: Diaphragm electromyogram (EMG) from a multipair esophageal electrodes and airflow derived from pneumotachography were recorded during overnight polysomnography in 13 patients with stable COPD recruited from outpatient clinic of First Affiliated Hospital of Guangzhou Medical College from May 2010 to May 2011. Changes in diaphragm EMG and ventilation during wakefulness and different sleep stages were observed., Results: Diaphragm EMG decreased by 26% in non-rapid eye movement sleep (NREM) stage and 39% in rapid eye movement (REM) as compared with wakefulness. Coinciding with change in diaphragm EMG, ventilation (VE) (ml×min(-1)×kg(-1)) significantly decreased from wakefulness (156 ± 53) ml×min(-1)×kg(-1) to steady NREM stage (112 ± 35) ml×min(-1)×kg(-1) (P < 0.05) and further decreased from NREM stage to REM stage (95 ± 27) ml×min(-1)×kg(-1) (P < 0.05). Oxygen saturation also decreased significantly from 97.1% ± 1.8% in wakefulness to REM stage (94.0% ± 3.9%) (P < 0.01)., Conclusion: Reduced neural respiratory drive contributes to nocturnal hypoventilation in COPD patients.