Treatment of obstructive sleep apnea with a simple CPAP device.

PURPOSE: CPAP is the "gold standard" treatment for obstructive sleep apnea (OSA). Current CPAP models have developed additional functions including automatic CPAP and pressure relief. However, CPAP adherence has not improved over the last three decades. Many patients in low-income countries cannot afford these CPAP devices. A novel simple CPAP device with a fixed pressure without pressure controller was developed. METHODS: Manual CPAP pressure titration was performed in 127 patients with OSA. Six patients with a titration pressure higher than 11 cmH2O and 14 patients who could not tolerate CPAP were excluded, leaving 107 participating in the following 2 studies. In study one, 54 of 107 patients were treated by both conventional fixed CPAP and simple CPAP in random order. In the second study, another 53 patients were treated by both autoCPAP in automatic function and simple CPAP in random order. Simple CPAP was fixed at 10 cmH2O, 8 cmH2O, and 6 cmH2O for patients whose titration pressure was between 9-10, 7-8, and ≤ 6 cmH2O, respectively. Conventional fixed CPAP device was set exactly the same as manual titration pressure. RESULTS: All patients whose manual titration pressure ≤ 10 cmH2O were effectively treated by simple CPAP (AHI 40.7 ± 2.3 events/h before vs 2.5 ± 0.3 events/h after, p < 0.001). Patients expressed similar preferences for simple CPAP, autoCPAP, and conventional fixed CPAP (p > 0.05). CONCLUSIONS: We conclude that a novel simple CPAP is an alternative treatment for most patients with OSA, which may widen access to CPAP therapy in the developing countries because of its low cost.

[Prevalence of central sleep apnea in different age groups of children with sleep apnea-hypopnea].

OBJECTIVE: To explore the prevalence of central sleep apnea in different age groups of children with sleep apnea-hypopnea (SAH). METHODS: A total of 431 children with SAH diagnosed by overnight polysomnography at our Sleep Center were retrospectively studied. They were divided into 3 groups based on their ages: toddler group (1 - < 3 years old), preschool group (3 - < 6 years old) and school group (6 - < 13 years old). The relationship between age and different types of apnea-hyponea index (AHI) was analyzed. And the prevalence of central sleep apnea and sleep structure were compared between the groups. RESULTS: A negative correlation existed between age and central sleep apnea index (r = -0.322, P < 0.01). However, there was no correlation between age and obstructive apnea index (P > 0.05). AHI was similar in different age groups, but the medians of central sleep apnea index for toddler, preschool and school groups were 2.35, 1.50 and 0.90 events/h respectively (all P < 0.01). Sleep structure was similar between the groups (P > 0.05). CONCLUSIONS: Central sleep apnea is common in children with sleep disordered breathing. The younger their ages, a higher prevalence of central sleep apnea.

[Assessment of neural respiratory drive in humans].

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.

Absence of dynamic hyperinflation during exhaustive exercise in severe COPD reflects submaximal IC maneuvers rather than a nonhyperinflator phenotype.

Approximately 20% of chronic obstructive pulmonary disease (COPD) patients have been considered to have a "nonhyperinflator phenotype." However, this judgment depends on patients making a fully maximal inspiratory capacity (IC) maneuver at rest, since the IC during exercise is compared with this baseline measurement. We hypothesized that IC maneuvers at rest are sometimes submaximal and tested this hypothesis by measuring IC and associated neural respiratory drive at rest and during inhalation of CO2 and exercise in patients with COPD. Twenty-six COPD patients [age 66 ± 6 yr, mean forced expiratory volume in 1 s (FEV1) 40 ± 11% predicted] and 39 healthy subjects (age 39 ± 14 yr, FEV1 98 ± 12% predicted) were studied. IC and the diaphragm electromyogram (EMGdi) associated with it (EMGdi-IC) and forced inspiratory vital capacity (FIVC) and its corresponding EMGdi (EMGdi-FIVC) were measured during inhalation of 8% CO2 (8% CO2-92% O2) and room air. Incremental exhaustive cycle ergometer exercise was also performed in both patients with COPD and healthy subjects. IC, EMGdi-IC, FIVC, and EMGdi-FIVC during breathing 8% CO2 were significantly greater than those during breathing room air in both patients with COPD and healthy subjects (all P < 0.001). EMGdi-IC in patients with COPD constantly increased during exercise from 145 ± 40 µV at rest to 185 ± 52 µV at the end of exercise but change in IC was variable. Neural respiratory drive and its relevant IC increased during hypercapnia. Exercise-related hypercapnia in patients with COPD raises neural respiratory drives, which compensate for IC reduction, leading to underestimation of dynamic hyperinflation measured by IC at rest breathing room air.NEW & NOTEWORTHY Inspiratory capacity measured during hypercapnia is higher than that during eucapnia. Thus total lung capacity is not always be achieved by a standard inspiratory capacity maneuver, leading to risk of underestimation of dynamic hyperinflation in patients with severe chronic obstructive pulmonary disease after exhaustive exercise.

[Neural respiratory drive in patients with obstructive sleep apnea].

OBJECTIVE: To evaluate the variability of neural respiratory drive in patients with obstructive sleep apnea (OSA) and the effect of continuous positive airway pressure (CPAP) upon neural respiratory drive. METHODS: We recorded diaphragm electromyogram (EMGdi) with multi-pair esophageal electrodes and its variability during wakefulness, sleep and treatment with CPAP in 13 patients with moderate to severe OSA diagnosed by an overnight full polysomnography (OSA group). Six normal subjects (control group) were also studied. RESULTS: Coefficient of variation of EMGdi (CV-EMGdi) during wakefulness (15.4% +/- 3.8%) was similar to that during sleep (17.3% +/- 5.2, P > 0.05) in the control group. The CV-EMGdi during wakefulness, sleep, sleep apnea events and treatment with CPAP in OSA group was 14.7% +/- 1.9%, 40.7% +/- 12.0%, 29.1% +/- 7.5% and 15.4% +/- 4.6% respectively, CV-EMGdi during sleep or sleep apnea events was larger than that during wakefulness (P < 0.01). However, there was no difference in the CV-EMGdi during wakefulness and during treatment with CPAP (P > 0.05). CONCLUSION: The variability of neural respiratory drive in patients with OSA is higher than that in normal subjects, and CPAP can reduce the variability of neural respiratory drive in patients with OSA.

catena-Poly[[diaquacadmium(II)]bis-(µ-pyridine-3-sulfonato)-κN:O;κO:N].

In the title polymeric complex, [Cd(C(5)H(4)NO(3)S)(2)(H(2)O)(2)](n), the Cd atom is located on a centre of inversion and is coordinated by two O atoms and two N atoms, derived from four different pyridine-3-sulfonate ligands, and two O atoms derived from two water mol-ecules, forming a distorted trans-N(2)O(4) octa-hedral geometry. The topology of the polymer is a one-dimensional chain mediated by bridging pyridine-3-sulfonate anions. These are connected into a three-dimensional architecture via hydrogen bonds.

catena-Poly[[diaqua-manganese(II)]-di-µ-pyridine-3-sulfonato-κN:O;κO:N].

In the title polymeric complex, [Mn(C(5)H(4)NO(3)S)(2)(H(2)O)(2)](n), the Mn atom is located on a centre of inversion and is coordinated by two O atoms and two N atoms derived from four different pyridine-3-sulfonate (pySO(3)) ligands, and two O atoms derived from two water mol-ecules in a distorted trans-N(2)O(4) octa-hedral geometry. The metal atoms are bridged by the pySO(3) ligands to form a one-dimensional chain. The chains are further connected into a three-dimensional architecture via hydrogen bonds.

Poly[[µ(3)-3-(3-pyrid-yl)acrylato-κN:O:O'][µ(2)-3-(3-pyrid-yl)acrylato-κO,O':O][µ(2)-3-(3-pyrid-yl)acrylato-κO:O')]gadolinium(III)].

In the title compound, [Gd(C(8)H(6)NO(2))(3)](n), the Gd(III) ion is in a bicapped trigonal prismatic coordination environment formed by seven O atoms and one N atom, derived from seven different 3-(3-pyrid-yl)acrylate (3-PYA) ligands. Gd(III) ions are bridged by bidentate and tridentate 3-PYA ligands, resulting in a two-dimensional structure.

catena-Poly[[aqua-[3-(3-pyrid-yl)acrylato]gadolinium(III)]-bis-[µ-3-(3-pyrid-yl)acrylato]].

In the title compound, [Gd(C(8)H(6)NO(2))(3)(H(2)O)](n), the gadolinium(III) ion is coordinated by eight carboxyl-ate O atoms and one water mol-ecule. The carboxyl-ate ligands bridge pairs of gadolinium(III) ions, forming a zigzag chain along [100]. Hydrogen bonds link the chains into sheets parallel to (001).

Tai Chi and Pulmonary Rehabilitation Compared for Treatment-Naive Patients With COPD: A Randomized Controlled Trial.

BACKGROUND: In COPD, functional status is improved by pulmonary rehabilitation (PR) but requires specific facilities. Tai Chi, which combines psychological treatment and physical exercise and requires no special equipment, is widely practiced in China and is becoming increasingly popular in the rest of the world. We hypothesized that Tai Chi is equivalent (ie, difference less than ±4 St. George's Respiratory Questionnaire [SGRQ] points) to PR. METHODS: A total of 120 patients (mean FEV1, 1.11 ± 0.42 L; 43.6% predicted) bronchodilator-naive patients were studied. Two weeks after starting indacaterol 150 µg once daily, they randomly received either standard PR thrice weekly or group Tai Chi five times weekly, for 12 weeks. The primary end point was change in SGRQ prior to and following the exercise intervention; measurements were also made 12 weeks after the end of the intervention. RESULTS: The between-group difference for SGRQ at the end of the exercise interventions was -0.48 (95% CI PR vs Tai Chi, -3.6 to 2.6; P = .76), excluding a difference exceeding the minimal clinically important difference. Twelve weeks later, the between-group difference for SGRQ was 4.5 (95% CI, 1.9 to 7.0; P < .001), favoring Tai Chi. Similar trends were observed for 6-min walk distance; no change in FEV1 was observed. CONCLUSIONS: Tai Chi is equivalent to PR for improving SGRQ in COPD. Twelve weeks after exercise cessation, a clinically significant difference in SGRQ emerged favoring Tai Chi. Tai Chi is an appropriate substitute for PR. TRIAL REGISTRY: ClinicalTrials.gov; No.: NCT02665130; URL: www.clinicaltrials.gov.

Association Between the CYP1B1 Polymorphisms and Lung Cancer Risk: A Meta-Analysis.

The previously published data on the association between the cytochrome P450 1B1 Leu432Val, Asn453Ser, and Ala119Ser polymorphisms and lung cancer risk have remained controversial. Hence, we performed a meta-analysis to investigate the association between cytochrome P450 1B1 Leu432Val, Asn453Ser, and Ala119Ser polymorphisms and lung cancer risk under different inheritance models. A total of 22 studies were identified, including 2881 cases and 3653 controls for Leu432Val polymorphism (from 13 studies), 3009 cases and 3887 controls for Asn453Ser polymorphism (from 5 studies), and 1301 cases and 2045 controls for Ala119Ser polymorphism (from 4 studies). Overall, significant association was observed between cytochrome P450 1B1 Leu432Val polymorphism and lung cancer risk (dominant model: odds ratio = 1.29, 95% confidence interval = 1.08-1.53; recessive model: odds ratio = 1.21, 95% confidence interval = 1.05-1.39; additive model: odds ratio = 1.43, 95% confidence interval = 1.21-1.69) when all the eligible studies were pooled into the meta-analysis. In the further stratified and sensitivity analyses, significantly increased lung cancer risk was also observed in caucasians and smokers. No significant association was observed between cytochrome P450 1B1Asn453Ser and Ala119Ser polymorphisms and lung cancer risk in overall analysis. In summary, this meta-analysis suggests that cytochrome P450 1B1Leu432Val polymorphism is associated with increased lung cancer risk in caucasians and smokers.

Physiological responses to Tai Chi in stable patients with COPD.

We compared the physiological work, judged by oxygen uptake, esophageal pressure swing and diaphragm electromyography, elicited by Tai Chi compared with that elicited by constant rate treadmill walking at 60% of maximal load in eleven patients with COPD (Mean FEV1 61% predicted, FEV1/FVC 47%). Dynamic hyperinflation was assessed by inspiratory capacity and twitch quadriceps tension (TwQ) elicited by supramaximal magnetic stimulation of the femoral nerve was also measured before and after both exercises. The EMGdi and esophageal pressure at the end of exercise were similar for both treadmill exercise and Tai Chi (0.109±0.047 mV vs 0.118±0.061 mV for EMGdi and 22.3±7.1 cmH2O vs 21.9±8.1 cmH2O for esophageal pressure). Moreover the mean values of oxygen uptake during Tai Chi and treadmill exercise did not differ significantly: 11.3 ml/kg/min (51.1% of maximal oxygen uptake derived from incremental exercise) and 13.4 ml/kg/min (52.5%) respectively, p>0.05. Respiratory rate during Tai Chi was significantly lower than that during treadmill exercise. Both Tai Chi and treadmill exercise elicited a fall in IC at end exercise, indicating dynamic hyperinflation, but this was statistically significant only after treadmill exercise. TwQ decreased significantly after Tai Chi but not after treadmill. We conclude that Tai Chi constitutes a physiologically similar stimulus to treadmill exercise and may therefore be an acceptable modality for pulmonary rehabilitation which may be culturally more acceptable in some parts of the world.

Effect of expiratory load on neural inspiratory drive.

BACKGROUND: Neural respiratory drive is usually measured during inspiration, even in patients with chronic obstructive pulmonary disease (COPD) in whom the primary physiological deficit is expiratory flow limitation. The purpose of the study was to test the hypothesis that inspiratory muscle neural respiratory drive could be used to assess expiratory load. METHODS: Ten healthy young men, (26 ± 4) years old, were asked to expire through a tube immersed in water where an expiratory load was required. The load was judged by the depth of the tube in water and the different loads (0 cmH2O, 10 cmH2O, 20 cmH2O and 30 cmH2O) were randomly introduced. Each expiratory load lasted for 3 - 5 minutes and inspiration was unimpeded throughout. Diaphragm electromyogram (EMG) and transdiaphragmatic pressure were recorded by a catheter with 10 metal coils and two balloons. Incremental cycle exercise with and without an expiratory load at 30 cmH2O was also performed. RESULTS: Neural drive during expiratory loaded breathing was larger than during unloaded breathing but neural drive did not increase proportionally with increasing expiratory load; neural drive during expiratory loading at 0, 10, 20 and 30 cmH2O was (10.1 ± 3.1) µV, (16.7 ± 7.3) µV, (18.4 ± 10.7) µV and (22.9 ± 13.2) µV, respectively. Neural drive as a percentage of maximum at the end of exercise with or without load was similar ((57.4 ± 11.0)% max vs. (62.7 ± 16.4)% max, P > 0.05). CONCLUSION: Neural respiratory drive measured at inspiration does not accurately quantify expiratory load either at rest or during exercise.