Low leptin concentration may identify heart failure patients with central sleep apnea

Low leptin concentration has been shown to be associated with central sleep apnea in heart failure patients. We hypothesized that low leptin concentration predicts central sleep apnea. Consecutive ambulatory New York Heart Association (NYHA ) classes I–IV heart failure patients were studied prospectively, including measurement of serum leptin, echocardiography and polysomnography. Sleep apnea was defined by type (central/mixed/obstructive) and by apnea–hypopnea index ≥5 by polysomnography. Subjects were divided into four groups by polysomnography: (1) central sleep apnea, (2) mixed apnea, (3) no apnea and (4) obstructive sleep apnea. Fifty‐six subjects were included. Eighteen subjects were diagnosed with central sleep apnea, 15 with mixed apnea, 12 with obstructive apnea and 11 with no sleep apnea. Leptin concentration was significantly lower in central sleep apnea compared to obstructive apnea (8 ± 10.7 ng mL^?1 versus 19.7 ± 14.7 ng mL^?1, P  ? 0.01) or no sleep apnea (8 ± 10.7 ng mL^?1 versus 17.1 ± 8.4 ng mL^?1, P  ? 0.01). Logistic regression showed leptin to be associated independently with central sleep apnea [odds ratio (OR ): 0.19; 95% confidence interval (CI ): 0.06–0.62; area under the curve (AUC ): 0.80, P  < 0.01]. For the detection of central sleep apnea, a cut‐off value for leptin concentration 5 ng mL^?1 yielded a sensitivity of 50% and specificity of 89%. In conclusion, a low leptin concentration may have utility for the screening of heart failure patients for central sleep apnea.     

The use and effectiveness of adaptive servo ventilation in central sleep apnea: a study of consecutive sleep clinic patients

The use of adaptive servo ventilation to treat central sleep apnea in the clinical setting is incompletely understood and could be under‐utilized. We reviewed our experience of adaptive servo ventilation use in patients with central sleep apnea. This study shows the effectiveness of adaptive servo ventilation in treating patients with central sleep apnea, irrespective of a predisposing factor, as assessed during a 4‐week treatment trial. Results show that adaptive servo ventilation was effective and superior to continuous positive airway pressure in controlling central sleep apnea and improving symptoms. Only a small proportion of these patients had comorbid heart failure. Early treatment with adaptive servo ventilation may improve long‐term adherence to therapy. These findings highlight the utility of adaptive servo ventilation in the management of central sleep apnea.     

Effects of continuous positive airway pressure on cognitition and neuroimaging data in sleep apnea

Obstructive sleep apnea (OSA) has been associated with a broad range of neurocognitive difficulties. The current view is that the neurocognitive impairment in OSA is due to the adverse effects of sleep fragmentation and/or intermittent hypoxia. The overall picture of cognitive deficits in OSA is complex. On balance, there appears to be negative effects of OSA on cognition, most likely in the domains of attention/vigilance, verbal and visual delayed long-term memory, visuospatial/constructional abilities, and executive dysfunction. Continuous positive airway pressure (CPAP) is the most effective and widely used treatment of OSA. In the majority of studies of OSA patients treated with CPAP, attention/vigilance improved, but changes in global functioning, executive functioning, and memory improved in about half of the studies. This may be due, in part, to variability in study design and sampling methodology across studies.     

Continuous positive airway pressure lowers blood pressure in hypertensive patients with obstructive sleep apnea

Summary Question of the study Obstructive sleep apnea (OSA) and hypertension are frequently associated and probably causally related. We investigated the influence of continuous positive airway pressure (CPAP) on blood pressure (BP) in OSA. Patients and Methods Fourty-four patients in whom CPAP-therapy had been successfully applied for treatment of OSA (median apnea-hypopopnea-index [AHI] 57.5/h) were included. Non-invasive 24-hour BP was measured at 15  min intervals before and with CPAP. Results After 1 – 3 days of CPAP, 24-hour systolic and diastolic BP in the hypertensive patients (n = 32) decreased from a median of 141 (129 – 173, 25 % – 75 % interquartile range) mmHg to 136 (118 – 157) mmHg (p = 0.004) and from 90 (80 – 107) mmHg to 88 (77 – 99) mmHg (p = 0.001), respectively, but was unchanged in the normotensives (n = 10). After 4 – 6 months of CPAP, 24-hour systolic and diastolic BP in a hypertensive subgroup (n = 19) decreased from a median of 140 (131 – 142) mmHg to 131 (122 – 143) mmHg (p = 0.01) and from 88 (86 – 94) mmHg to 84 (80 – 87) mmHg (p = 0.02), respectively, but was unchanged in a normotensive subgroup (n = 8). After long-term CPAP, there was a small weight reduction in the hypertensive patients. Subgroup analysis of 13 hypertensives with stable weight confirmed a significant BP-reduction. Conclusions In OSA with associated hypertension, CPAP has a specific BP-lowering effect. This suggests that both disorders are causally related.     

Acute effects of different levels of continuous positive airway pressure on cardiac autonomic modulation in chronic heart failure and chronic obstructive pulmonary disease

Introduction

Non-invasive ventilation may improve autonomic modulation and ventilatory parameters in severely disabled patients. The aim of the present study was to evaluate the physiological influence of acute treatment with different levels of continuous positive airway pressure (CPAP) on the autonomic balance of heart and respiratory responses in patients with stable chronic obstructive pulmonary disease (COPD) and chronic heart failure (CHF).

Materials and methods

A COPD group (n = 10), CHF group (n = 8) and healthy subjects (n = 10) were evaluated. The participants were randomized to receive three different levels of CPAP on the same day: sham ventilation (Sham), 5 cmH₂0 (CPAP5) and 10 cmH₂0 (CPAP10) for 10 min. Respiratory rate, end tidal carbon dioxide (E_TCO₂), peripheral oxygen saturation (SpO₂), heart rate (HR), blood pressure and heart rate variability in the time and frequency domains were measured during spontaneous breathing and under the sham, CPAP5 and CPAP10 conditions.

Results

All groups experienced a reduction in E_TCO₂ values during treatment with CPAP (p < 0.05). CPAP increased SpO₂ and HR in the COPD group (p < 0.05). The COPD group also had lower RMSSD values during treatment with different levels of CPAP when compared to the control group (p < 0.05). In the CHF group, CPAP5 and CPAP10 increased the SDNN value (p < 0.05). CPAP10 reduced the SDNN value in the COPD group (p < 0.05).

Conclusion

The findings suggest that CPAP may cause improvements in the neural control of heart rate in patients with stable COPD and CHF. For each patient, the “best CPAP level” should be defined as the best respiratory response and autonomic balance.     

Predictors of continuous positive airway pressure use during the first week of treatment

This study aimed to identify pre‐treatment and immediate early treatment factors predicting continuous positive airway pressure (CPAP) use during the first week of therapy, when the pattern of non‐adherence is established. Four domains of potential predictors were examined: pre‐treatment demographic and clinical factors, patients’ perceived self‐efficacy, treatment delivery (mask leak and bothering side effects) and immediate disease reduction (residual respiratory events and flow limitation). The Autoset? Clinical System objectively documented daily CPAP use, mask leak, residual respiratory events and flow limitation. Ninety‐one CPAP‐naive patients with newly diagnosed obstructive sleep apnea were followed for 1 week after treatment initiation. Mean CPAP daily use during the first week was 3.4 ± 2.7 h, with significantly lower use observed in black than non‐black participants (2.7 versus 4.4 h, respectively, P = 0.002). Less intimacy with partners caused by CPAP was the only treatment side effect correlated with CPAP use (r = ?0.300, P = 0.025). Reduced CPAP use during the first week was associated simultaneously with being black, higher residual apnea–hypopnea index and the treatment side effect of less intimacy with partners. The three factors together accounted for 25.4% of the variance in the CPAP use (R² = 0.254, P < 0.01). These data suggest the need to assess the impact of CPAP on intimacy and troubleshooting aspects of the treatment that interfere with sexual relationships. Assessing the presence of residual respiratory events may be important in promoting CPAP adherence. The association of race and CPAP use needs to be explored further by including more socioeconomic information.     

Good long‐term adherence to continuous positive airway pressure therapy in patients with resistant hypertension and sleep apnea

Although adequate adherence is paramount in achieving the beneficial effects of continuous positive airway pressure therapy in patients with obstructive sleep apnea, long‐term adherence and the variables involved in continuous positive airway pressure compliance in patients with resistant hypertension and obstructive sleep apnea are yet unknown. We conducted a prospective, multicentre, observational study in 177 patients recruited from hypertensive units with resistant hypertension confirmed by means of 24‐hr blood pressure monitoring (blood pressure ≥ 130 and/or ≥ 80 mmHg, despite taking at least three antihypertensive drugs or < 130/80 mmHg with > 3 drugs) and obstructive sleep apnea (apnea–hypopnea index ≥ 5 in a respiratory polygraph) who were prescribed continuous positive airway pressure treatment. Good adherence was defined as an average cumulative continuous positive airway pressure use of ≥ 4 hr per night at the end of the follow‐up. A multivariate Cox regression analysis was performed to identify independent predictors of continuous positive airway pressure adherence. Patients were followed for a median of 57.6 (42–72) months after initiating continuous positive airway pressure therapy. At the end of the follow‐up, the median continuous positive airway pressure use was 5.7 (inter‐quartile range 3.9–6.6) hr per night, and 132 patients (74.5%) showed good continuous positive airway pressure adherence. The only baseline variable associated with poor adherence was the presence of previous stroke (hazard ratio 4.00, 95% confidence interval 1.92–8.31). Adequate adherence at 1 month also predicted good adherence at the end of the follow‐up (hazard ratio 14.4, 95% confidence interval 4.94–56). Both variables also predicted adherence at a threshold of 6 hr per night. Our results show that good continuous positive airway pressure adherence is an achievable and feasible goal in patients with resistant hypertension and obstructive sleep apnea. Previous stroke and short‐term adherence predicted long‐term adherence.     

家庭无创正压通气在慢性左室心力衰竭中的疗效

目的:探讨家庭无创正压通气在慢性左室心力衰竭中的治疗作用.方法:选择2016年1月至12月于保定市第一医院就诊的51例慢性左室心力衰竭患者进行观察,根据患者是否同意使用呼吸机分为两组:对照组给予常规抗心力衰竭治疗,治疗组给予常规抗心力衰竭和家庭无创正压通气治疗,治疗1年后观察两组临床症状、动脉血氧分压(arterial partial pressure of oxygen,PaO2)、6分钟步行试验(6-minute walking test,6MWT)、脑钠肽(brain natriuretic peptide,BNP)水平、左室射血分数(left ventricular ejection fraction,LVEF).结果:治疗1年后,治疗组临床症状、PO2、6MWT、BNP水平、LVEF均有显著改善,明显优于对照组,差异有统计学意义(P<0.05).结论:家庭无创正压通气有助于改善慢性左室心力衰竭患者的心功能,维持心功能的稳定,提高患者生活质量.     

Nasal pillows as an alternative interface in patients with obstructive sleep apnoea syndrome initiating continuous positive airway pressure therapy

Side‐effects directly due to the nasal mask are common in patients with obstructive sleep apnoea syndrome (OSAS) commencing continuous positive airway pressure (CPAP). Recently, nasal pillows have been designed to overcome these issues. Limited evidence exists of the benefits and effectiveness of these devices. Twenty‐one patients (19 male, 49 ± 10 years) with the established diagnosis of OSAS [apnoea/hypopnoea index (AHI): 52 ± 22] and who had a successful CPAP titration were commenced on CPAP therapy (10 ± 2 cmH2O), and randomized to 4 weeks of a nasal pillow (P) and a standard nasal mask (M) in a crossover design. Outcome measures were objective compliance, AHI, quality of life, Epworth Sleepiness Score (ESS) and CPAP side‐effects. There was no difference in compliance (M versus P: 5.1 ± 1.9 h versus 5.0 ± 1.7 h; P = 0.701) and AHI (2.6 ± 2.7 versus 3.0 ± 2.9; P = 0.509). Quality of life and ESS improved with CPAP, but there was no difference in the extent of improvement between both devices. Usage of nasal pillows resulted in less reported pressure on the face and more subjects found the nasal pillow the more comfortable device. However, there was no clear overall preference for either device at the end of the study (mask = 57%, pillow = 43%; P = 0.513). The applied CPAP pressure did not correlate with compliance, AHI and ESS. Furthermore, no differences in outcome parameters were noted comparing groups with CPAP pressure <10 and ≥10 cm H₂O. Nasal pillows are equally effective in CPAP therapy, but do not generally lead to improved compliance.     

An innovative nasal continuous positive airway pressure assembly

Continuous positive airway pressure is required by patients of obstructive sleep apnea to prevent any obstruction of airways. This requires CPAP machines which are costly, have electrical dependence and are not readily available. The nasal CPAP assembly devised by us overcomes most of these limitations and can be made from easily available materials.     

Impact of continuous positive airway pressure (CPAP) on quality of life in patients with obstructive sleep apnea (OSA)

Obstructive sleep apnea is a chronic illness with increasing prevalence. In addition to associated cardiovascular comorbidities, obstructive sleep apnea syndrome has been linked to poor quality of life, occupational accidents, and motor vehicle crashes secondary to excessive daytime sleepiness. Although continuous positive airway pressure is the gold standard for sleep apnea treatment, its effects on quality of life are not well defined. In the current study we investigated the effects of treatment on quality of life using the data from the Apnea Positive Pressure Long‐term Efficacy Study (APPLES), a randomized controlled trial of continuous positive airway pressure (CPAP) versus sham CPAP. The Calgary Sleep Apnea Quality of Life Index (SAQLI) was used to assess quality of life. Overall we found no significant improvement in quality of life among sleep apnea patients after CPAP treatment. However, after stratifying by OSA severity, it was found that long‐term improvement in quality of life might occur with the use of CPAP in people with severe and possibly moderate sleep apnea, and no demonstrable improvement in quality of life was noted among participants with mild obstructive sleep apnea.     

Diagnosis of sleep-disordered breathing in patients with chronic heart failure: evaluation of a portable limited sleep study system

Sleep-disordered breathing (SDB) is common in chronic heart failure (CHF), affects disease progression and presents a potential therapeutic target. This study was designed to test the hypothesis that there would be good agreement in diagnostic outcome between home limited sleep studies and in-laboratory polysomnography (PSG) in the identification of SDB in patients with CHF. We performed synchronous in-laboratory Embletta and PSG, and home Embletta studies, prospectively in 20 consecutive patients with stable symptomatic CHF (ejection fraction 33 +/- 12%) on optimal medical therapy. Sleep efficiency was poor at 57 +/- 21%. Unlike synchronous in-laboratory Embletta (kappa coefficient 0.63, P < 0.01), home Embletta showed poor agreement with PSG (kappa coefficient 0.27, P = 0.06). Positive and negative predictive values for home Embletta in detecting SDB were 83% and 57% respectively. In this relatively small study, agreement in diagnostic outcome between home Embletta and PSG, and negative predictive value for the home Embletta, were poor. We explore possible explanations for this, both technical and situational, which should be taken into consideration when considering potential screening or diagnostic tools for SDB in patients with CHF.     

Continuous positive airway pressure treatment for obstructive sleep apnoea reduces resting heart rate but does not affect dysrhythmias: a randomised controlled trial

Obstructive sleep apnoea (OSA) is associated with cardiovascular morbidity and may precipitate cardiac dysrhythmias. Uncontrolled reports suggest that continuous positive airway pressure (CPAP) may reduce dysrhythmia frequency and resting heart rate. We undertook a randomised controlled trial of therapeutic CPAP and compared with a subtherapeutic control which included an exploration of changes in dysrhythmia frequency and heart rate. Values are expressed as mean (SD). Eighty-three men [49.5 (9.6) years] with moderate–severe OSA [Oxygen Desaturation Index, 41.2 (24.3) dips per hour] underwent 3-channel 24-h electrocardiograms during normal daily activities, before and after 1 month of therapeutic ( n  = 43) or subtherapeutic ( n  = 40) CPAP. Recordings were manually analysed for mean heart rate, pauses, bradycardias, supraventricular and ventricular dysrhythmias. The two groups were well matched for age, body mass index, OSA severity, cardiovascular risk factors and history. Supraventricular ectopics and ventricular ectopics were frequently found in 95.2% and 85.5% of patients, respectively. Less common were sinus pauses (42.2%), episodes of bradycardia (12%) and ventricular tachycardias (4.8%). Compared with subtherapeutic control, CPAP reduced mean 24-h heart rate from 83.0 (11.5) to 79.7 (9.8) ( P  < 0.002) in the CPAP group compared with a non-significant rise ( P  = 0.18) from 79.0 (10.4) to 79.9 (10.4) in the subtherapeutic group; this was also the case for the day period analysed separately. There was no significant change in the frequencies of dysrhythmias after CPAP. Four weeks of CPAP therapy reduces mean 24-h heart rate possibly due to reduced sympathetic activation but did not result in a significant decrease in dysrhythmia frequency.     

Periodic limb movements and obstructive sleep apneas before and after continuous positive airway pressure treatment

Periodic limb movements during sleep (PLMS) and obstructive sleep apnea syndrome (OSAS) are two common sleep disorders. The similarity in periodicity of periodic limb movements (PLMs) and obstructive sleep apneas (OSAs) led us to hypothesize the existence of a common central generator responsible for the periodicity of both OSAs and PLMs. In order to test this hypothesis, we compared apnea periodicity before continuous positive airway pressure (CPAP) treatment with PLMs periodicity during CPAP treatment in 26 OSA patients, consecutively recorded and treated in our sleep laboratory. The investigation on CPAP was performed twice, once during the initial evaluation and once during a follow-up evaluation after 3 months of home treatment with CPAP. Our results showed that, in this sample, 16 patients out of 26 had an association of OSAS and PLMS, defined as the occurrence of at least 5 PLMs per hour of sleep. The mean apnea interval - measured as the time between the beginning of two successive apneas - was 43.1 s (+/-15.2, SD) and the mean PLM interval - calculated in the same way - was 29.6 s (+/-15.2) during the baseline night, 28.5 s (+/-15.7) during the first CPAP night, and 29.8 s (+/-14.8) during the second CPAP night. Thus, the periodicity of the two phenomena (apneas and PLMs) was different, both before and after CPAP treatment (P< 0.05). When considering the interval between the end of an event (apnea or PLM) and the beginning of the next one the mean apnea interval was 19.5 s (+/-11. 6), and the mean PLM interval was 28.1 s (+/-15.3) during the untreated night, 26.6 s (+/-16) during the first CPAP night and 27.9 s (+/-15) during the second CPAP night. The shortening of apnea intervals with this method of measuring intervals reflects the longer duration of apneas as compared to PLMs. Again the intervals between PLMs were not different between each other but the intervals between apneas were different from the intervals between PLMs (P< 0. 05) These results show that the periodicity of PLMs is different from that of OSAs, suggesting that sleep apneas and PLMs are not generated by a common central generator.     

Intrathoracic pressure changes and cardiovascular effects induced by nCPAP and nBiPAP in sleep apnoea patients

SUMMARY  The effect of nasal continuous positive airway pressure (nCPAP) and nasal bi-level positive airway pressure (nBiPAP) on intrathoracic pressure and haemodynamics during wakefulness was studied in a group of nine patients with severe sleep apnoea. No patient took cardiovascular medication.
Patients were studied with a Swan Ganz catheter, an arterial line and an oesophageal balloon. nCPAP and nBiPAP were applied in the following pressure sequence: 5, 10 and 15 cm H₂O of CPAP and 10/5 and 15/10 cm H₂O of nBiPAP. Measurements were made at the end of a 5-min period at each pressure level. Intrathoracic pressure was noted to increase to a level of approximately 50% of the pressure delivered at the mask. At a CPAP of 10 cm H₂O and above, as well as at BiPAP of 10/5 or higher, there was a decrease in cardiac output (CO) and cardiac index (CI). CI fell below the normal value in two of the patients. Transmural pulmonary artery pressure (PPA_tm) decreased at a CPAP of 15 cm H₂O and at both BiPAP levels. Transmural right atrial pressure (PRA_tm) decreased at both BiPAP levels. There were no differences in CO, CI, PPA_tm and PRA_tm between nCPAP and nBiPAP at equal inspiratory pressures. SaO₂ increased during BiPAP 15/10 cm H₂O, whereas heart rate and arterial blood pressure did not change significantly. The data presented here are consistent with the literature on positive end-expiratory pressure (PEEP) applied via intratracheal tube and are likely to be due to a reduced venous return. It is concluded that nasally applied positive pressure may have acute negative effects on cardiac function in patients with sleep apnoea.