Flow-volume curve abnormalities and obstructive sleep apnea syndrome

Recent reports have suggested that flow volume curve abnormalities may be of interest in the diagnosis of obstructive sleep apnea syndromes by showing either extrathoracic airway obstruction (ratio of expiratory flow to inspiratory flow at 50 percent of forced vital capacity [FEF50/FIF50] exceeding 1) or upper airway fluttering (indicated by a sawtooth aspect on the mid-half of the inspiratory part of the curve) or both. In our study, 57 patients referred for a suspected sleep apnea syndrome (SAS) underwent conventional spirometry, assessment of flow-volume curves, ENT examination, and polysomnography. Thirty patients had an obstructive SAS, four patients a central SAS, and 23 patients no SAS. Signs of upper airway fluttering (the sawtooth sign) were present in 61 percent of the patients with obstructive SAS and in 46 percent of the patients without obstructive SAS (central SAS or no SAS). Signs of extrathoracic upper airway obstruction (FEF50/FIF50 greater than 1) were present in 67 percent of the patients with obstructive SAS and in 71 percent of the patients without obstructive SAS. These results suggest that upper airway abnormalities, as reflected by abnormal flow volume curves, are not always associated with obstructive SAS; they favor the hypothesis of a central component in the mechanism of upper airway occlusion during sleep.     

Effects of ipratropium bromide (IPB) and its combination with salbutamol sulfate (SAS) in acute asthmatic attack

34 patients with acute asthmatic attack were studied in double-blind, randomized and crossover manner. Each of them was treated with following two protocols during two sequential days: 0.5 mg of ipratropium bromide (IPB), followed by 5 mg of salbutamol sulfate (SAS) 75 minutes later; or 5 mg of SAS, followed by another dose 35 minutes late. The drugs were delivered via a jet nebulizer. The effects and side-effects of the treatment were evaluated immediately before the first inhalation and at peak of bronchodilatation (60-75 minutes after IPB or 20-35 minutes after SAS). Compared with inhaled SAS, IPB produced considerable improvement in central airway parameters such as forced expiratory volume in one second (FEV1) peak expiratory flow (PEF) and respiratory resistance (Rrs) (P greater than 0.05), but less improvement in peripheral airway parameters such as forced vital capacity (FVC) and maximal mid-expiratory flow (MMEF) (P less than 0.01). The sequential inhaled SAS after IPB improved all five parameters (P less than 0.01), but the repeated dose of SAS increased only MMEF (P less than 0.01). Compared with double-dose SAS, the sequential treatment with IPB and SAS 1 ed to considerable improvement in FVC and MMEF (P greater than 0.05), but greater improvement in FEV1, PEF and Rrs (P less than 0.01). Heart (rate and tremor scores after two doses of SAS increased significantly (P less than 0.01). It is concluded that IPB alone is less effective than beta-adrenoceptor agonist, but its combination with SAS would be an effective and safe treatment in acute asthmatic attack.     

睡眠呼吸暂停综合征与慢性心力衰竭

睡眠呼吸暂停综合征在慢性心力衰竭患者中高度流行;近年来的研究表明：睡眠呼吸暂停综合征可能通过多种机制影响慢性心力衰竭的进程;慢性心力衰竭又能引起或加重睡眠呼吸暂停;对合并有睡眠呼吸暂停综合征的慢性心力衰竭患者在抗心力衰竭治疗的基础上进行其他方式的治疗可进一步改善慢性心力衰竭患者的心功能,提高生活质量。     

Breathing abnormalities during sleep in patients with chronic heart failure

Polysomnography was carried out in 11 adult outpatients with stable chronic heart failure (CHF) due to valvular heart disease in order to investigate respiratory abnormalities during sleep. The subjects consisted of 6 males and 5 females and their ages ranged from 54 to 76 years. A coexisting central dominant sleep apnea syndrome (SAS) was found in 4 males, 3 of whom had evidence of nasal obstruction. A successful mitral valve replacement in one patient with central dominant SAS was associated with a reduction in the frequency of sleep apnea. The results suggest complications caused by respiratory abnormalities during sleep are common and should be considered in the management of patients with CHF.     

Budd-Chiari syndrome with medullar compression

We report a case of Budd-Chiari syndrome caused by protein C deficiency. The association of thrombosis of the the inferior vein cava of the hepatic vein resulted in the development of epidural varices and a central and peripheral neurological syndrome. These symptoms, which are atypical in this disease, resolved after surgical treatment of the Budd-Chiari syndrome (cavoatrial and mesocaval stenting).     

Tos crónica

Chronic cough (CC), or cough lasting more than 8 weeks, has attracted increased attention in recent years following advances that have changed opinions on the prevailing diagnostic and therapeutic triad in place since the 1970s. Suboptimal treatment results in two thirds of all cases, together with a new notion of CC as a peripheral and central hypersensitivity syndrome similar to chronic pain, have changed the approach to this common complaint in routine clinical practice. The peripheral receptors involved in CC are still a part of the diagnostic triad. However, both convergence of stimuli and central nervous system hypersensitivity are key factors in treatment success.     

睡眠呼吸暂停综合征与高血压治疗

目的　观察合并睡眠呼吸暂停综合征 (SAS)的高血压病患者 ,常规药物降压治疗及呼吸道正压通气治疗对血压的影响。方法　按照睡眠资料和 2 4h血压资料 ,分为单纯高血压组与合并SAS高血压组 ,观察常规降压药物治疗 4周后 2 4h血压变化及呼吸道正压通气治疗对合并SAS的高血压患者 2 4h血压影响。结果　 2 7例单纯高血压患者 ,常规药物降压治疗 4周后 ,2 4h平均收缩压、舒张压、夜间收缩压、舒张压均明显下降 (P <0 0 1)。 2 5例合并SAS的高血压患者 2 4h平均收缩压、舒张压、夜间舒张压有所下降 (P <0 0 5 ) ,但仍高于正常值 ,而夜间收缩压无明显变化。其中 19例合并SAS高血压患者加用一夜正压通气治疗后 ,2 4h平均血压进一步下降 ,夜间收缩压和舒张压明显降低 (P <0 0 1,P <0 0 1)。结论　合并有SAS的高血压患者多为难治性 ,单纯降压药物治疗效果欠佳 ,需要同时应用正压通气进行治疗。     

Sleep apnea in active acromegaly

Previous case reports have shown an association between acromegaly and the sleep apnea syndrome (SAS). Some of the patients described had central SAS, raising the possibility that an elevation of the growth hormone (GH) level may cause a defect in respiratory drive. We determined the prevalence of SAS in 21 patients with a history of acromegaly. We separated them into two groups based on serum GH concentrations. Ten patients had active acromegaly (mean GH concentration, 62.2 ng/mL; range, 12.6 to 148 ng/mL), while 11 patients had inactive acromegaly (mean GH, 3.2 ng/mL; range, 0.7 to 6.4 ng/mL). Four of the ten patients with active acromegaly had SAS; none of the 11 patients with inactive acromegaly had SAS. Three patients with SAS had the purely obstructive type, and one had the mixed central and obstructive type. The hypercapnic ventilatory response was normal in all patients tested and was not influenced by the GH level. We conclude that SAS is associated with active acromegaly and that the GH level does not affect the hypercapnic ventilatory response. The absence of SAS in successfully treated patients suggests that it may resolve after a normal GH level is restored.     

Effectiveness of short-term treatment with nocturnal oxygen therapy for central sleep apnea in patients with congestive heart failure

OBJECTIVES. To evaluate the short term effects of inhalation of oxygen at night in 51 patients with congestive heart failure (CHF) and sleep apnea syndrome (SAS). METHODS. Fifty-one patients with stable CHF (31 males, 20 females, mean age 79.0 +/- 11.9 years; brain natriuretic peptide level of > 100 pg/ml) were evaluated between September 2003 and August 2004, using a Morpheus monitor. The complication rate of SAS in patients with CHF was assessed and apnea hypopnea index, oxygen desaturation index 3%, heart rate, and autonomic nerve activity under room air compared to supplemental O2 (2 l/min) over two consecutive nights. RESULTS. Thirty-eight (75%)of the CHF patients had SAS. Of these SAS patients, 49% suffered from central SAS and 51% had obstructive SAS. Apnea hypopnea index and oxygen desaturation index 3% improved remarkably with supplemental oxygen (p < 0.001), in particular, the central SAS group demonstrated prominent improvement (p < 0.001). Obstructive SAS patients exhibited no significant changes (p = 0.3356), but tended to exacerbate the episodes of sleep apnea. Total heart rate was decreased (p = 0.0079). Nevertheless, heart rate variability analysis showed little effect of nocturnal oxygen therapy on the autonomic nervous system during sleeping. CONCLUSIONS. Nocturnal oxygen therapy improved the number of sleep apnea episodes and decreased total heart rate during sleep time for the CHF patients with central SAS, despite little influence on the autonomic nervous system, based upon assessment of heart rate variability. Obstructive SAS might exacerbate the episodes of sleep apnea.     

Pacemaker therapy in sleep apnea syndrome

Summary Sleep apnea syndrome (SAS) is a serious health problem that particularly afflicts patients with cardiovascular disease. Pathophysiologically, an obstructive form of SAS with loss of air flow despite thorax movements and a central form of SAS with simultaneous cessation of air flow and respiratory movements are distinguished. Central SAS is present in almost 50% of patients with severe heart failure (HF). It induces alternating bradycardia and tachycardia related to fluctuations of the vago-sympathetic tone. Suppression or reduction of heart rate fluctuations by pacing may mitigate sleep apnea. In HF with marked nocturnal bradycardia, increasing the heart rate may improve cardiac output, shorten circulation time and decrease pulmonary congestion, thus diminishing the apneic threshold. Potentially, stimulation of vagal and sympathetic nerve fibers behind the superior vena cava/right atrial junction by pacing may directly influence cardiac vagal or sympathetic afferent neurons reducing central sleep apnea episodes. In obstructive SAS, polysomnography characterizes a specific pattern of sleep apnea where bradycardia precedes the onset of apnea. This could result from hypervagotonia first inducing bradycardia and then apnea. Atrial overdrive pacing may counteract hypervagotonia by maintaining sympathetic activity. Pacing might not benefit obstructive SAS due to excessive adiposity, anatomical obstacles or unrelated to bradycardia. In the future, cardiac pacing might be considered as an ancillary therapy for SAS in patients with bradycardia and/or hypervagotonia during sleep. Larger studies need to confirm this hypothesis in patients without a conventional indication for pacing. Device recording of sleep apnea could become a powerful tool to guide SAS therapy.     

Sleep apnea syndrome and obesity

Obesity is a main risk factor for sleep apnea syndrome (SAS). The prevalence of SAS is especially high in massive obesity and in visceral obesity. The mechanisms of obstructive apneas in obesity are poorly known, but an increase in upper airway collapsibility probably plays an important role. Several cardiorespiratory complications of SAS, especially systemic arterial hypertension, diurnal alveolar hypoventilation and pulmonary arterial hypertension, are more frequent and more severe in obese patients. An important weight loss resulting from surgical treatment of obesity is often associated with a dramatic decrease in apnea-hypopnea index in patients with massive obesity. In patients with moderate obesity, dietary weight loss is associated with varying degrees of improvement in SAS. Pharyngoplasty and anterior mandibular positioning devices have a low success rate in patients with massive obesity. Nasal continuous positive airway pressure is often the only effective treatment in obese SAS patients.     

Prevalence of the sleep apnea syndrome in acromegaly population

The prevalence of sleep apnea syndrome (SAS) in acromegaly is high. Consequences of SAS are serious and are associated with increased morbidity and mortality. The aim of this study was to assess the relative frequency and predictive factors for SAS in a group of patients with acromegaly (n=55). The presence of SAS was evaluated using the Polymesam device. Hormonal and clinical examination consisted of assessment of growth hormone, insulin-like growth factor I plasma levels, body mass index (BMI), neck circumference, age, sex, treatment modes of acromegaly and ear, nose and throat (ENT) examination. The relative frequency of SAS in our group of patients with acromegaly was 75%. Independent predictors of SAS were: increased activity of acromegaly, higher age and neck circumference. No association between SAS and BMI and ENT findings was observed. The role of gender was controversial.     

Exercise tolerance, exercise hyperpnea and central chemosensitivity to carbon dioxide in sleep apnea syndrome in heart failure patients.

BACKGROUND: Sleep apnea syndrome (SAS) and exercise hyperpnea are common in patients with chronic heart failure (CHF), and although it is not known whether they are both regulated by the same mechanisms, the hypothesis of the present study was that they are related to augmented central chemosensitivity. METHODS AND RESULTS: The oxygen desaturation index (ODI) was evaluated in 29 patients and those with ODI > 5 times/h underwent polysomnography. Patients with an apnea-hypopnea index (AHI) > 15 /h without evidence of obstructive apnea were defined as central SAS (CSAS). Cardiopulmonary exercise testing was performed to determine peak oxygen uptake and the VE-VCO2 slope. A hypercapnic gas mixture (7% CO2/93% O2) was used to activate the central chemoreflex. Nine patients had central SAS (CHF-CSAS) and 20 did not have apnea (CHF-nonSAS). Patients with CHF-CSAS had a lower peak oxygen uptake than the CHF-nonSAS group (13.0+/-2.4 vs 16.9+/-4.3 ml x kg(-1) x min(-1), p < 0.05). There was a significant correlation between central chemosensitivity and the AHI (r = 0.63, p < 0.05), between central chemosensitivity and the VE - VCO2 slope (r = 0.50, p < 0.01), whereas the VE-VCO2 slope showed an insignificant tendency to correlate with AHI (r = 0.44, p = 0.07). Conclusion CHF-CSAS is associated with impaired exercise tolerance and elevated central chemosensitivity is the responsible mechanism for CSAS and exercise hyperpnea.     

Central and peripheral testosterone effects in men with heart failure: An approach for cardiovascular research

Heart failure (HF) is a syndrome recognized as a health problem worldwide. Despite advances in treatment, patients with HF still have increased morbidity and mortality. Testosterone is one of the most researched hormones in the course of HF. Growing interest regarding the effect of testosterone, on a variety of body systems, has increased the knowledge about its mechanisms of action. The terms central and peripheral effects are used to distinguish the effects of testosterone on cardiac and extracardiac structures. Central effects include influences on cardiomyocytes and electrophysiology. Peripheral effects include influences on blood vessels, baroreceptor reactivity, skeletal muscles and erythropoesis. Current knowledge about peripheral effects of testosterone may explain much about beneficiary effects in the pathophysiology of HF syndrome. However, central, i.e., cardiac effects of testosterone are to be further explored.     

A case of pure autonomic failure (PAF) with sleep apnea syndrome (SAS) and successful treatment of dysautonomia with nasal continuous positive airway pressure (CPAP)

A 72-year-old man was admitted to our hospital due to dysuria and frequent syncope. The patient had been well until the age of 70 years, when he began with these symptoms and neurogenic bladder was diagnosed in the other hospital. On admission, neurological examinations revealed no abnormal findings except blepharoptosis, anisocoria and orthostatic hypotension. Frequent apnea was evident during sleep. Autonomic function tests showed mainly sympathetic postganglionic dysfunction. Brain magnetic resonance imaging showed lacunar infarctions without cerebello-pontine atrophy or abnormal signals of the basal ganglia. We diagnosed pure autonomic failure (PAF) with sleep apnea syndrome (SAS). After starting nasal continuous positive airway pressure (CPAP) for SAS, his sneezing and sleep apnea drastically improved. Interestingly, CPAP also decreased the severity of orthostatic hypotension and syncope. Ambulatory blood pressure monitoring (ABPM) showed remarkable improvement in diurnal fluctuation of blood pressure after CPAP therapy. Although SAS is frequently associated with Shy-Drager syndrome but not with PAF, patients with PAF had been reported to have degenerative changes in the central nervous system overlapping with Shy-Drager syndrome or Lewy body disease. This case raised the possibility that nasal CPAP may be useful for orthostatic hypotension as well as SAS in neurodegenerative diseases.     

睡眠呼吸暂停综合征的发病及治疗

睡眠呼吸暂停综合征(sleep apnea syndrome,SAS)是以睡眠过程中频繁发生的呼吸暂停和血氧饱和度下降为特征的临床综合症,可引起心脑血管和全身各脏器的损害,严重危害人类的健康.本文就睡眠呼吸暂停综合症的发病机制、临床诊断及治疗进展作一简要综述,以期加强临床医生对SAS有一个更深入的认识,提高临床诊治水平...     

Effect of transsphenoidal surgery on sleep apnoea in acromegaly

OBJECTIVE: Sleep apnoea syndrome (SAS) is common in acromegaly and both diseases are independently associated with hypertension and insulin resistance contributing to increased morbidity and mortality. Pituitary surgery remains the principal treatment modality in acromegaly. The aim of this study was to assess the prevalence and risk factors of SAS in acromegaly and to analyze the effect of transsphenoidal adenomectomy on SAS and cardiovascular risk factors. SUBJECTS AND METHODS: Thirteen consecutive patients (seven women and six men, aged 25-77 years) with newly diagnosed acromegaly were prospectively studied. Biochemical assessment (IGF-I, GH, acid labile subunit, fasting blood glucose (FBG), insulin), overnight respiratory polygraphy, and an Epworth Sleepiness scale score (ESS) were obtained before and 12 weeks after surgery. SAS was defined by an ESS > or = 10 and > or = 5 apnoeas/hypopnoeas (central or obstructive) per hour. RESULTS: Six of the thirteen (46%) patients had SAS. Risk factors were male gender (83.3 vs 14.3% without SAS) and long disease duration until diagnosis of acromegaly (10.2 +/- 3.2 vs 4.6 +/- 3.6 years, mean +/- S.D.). Ten patients had a homeostasis assessment model score > or = 4 indicating insulin resistance and one had diabetes mellitus requiring insulin. Seven patients had hypertension (> or = 140/90 mmHg). Postoperatively, GH and IGF-I levels decreased, but only five patients were cured. However, SAS resolved in all patients irrespective of whether acromegaly was cured or not. FBG (5.5 +/- 1.2 vs 4.8 +/- 0.4 mmol/l) and systolic blood pressure (150.8 +/- 18.5 vs 130.8 +/- 17.5 mmHg) decreased in all SAS patients. CONCLUSION: We found a high prevalence of SAS in acromegaly patients, in particular, in men and those with long duration of disease. Importantly, a marked reduction of GH excess by transsphenoidal adenomectomy may cure SAS and improve insulin resistance and hypertension.     

Fatigue in neurological disorders

Chronic fatigue is a typical symptom of neurological diseases, and is most disabling in multiple sclerosis, postpoliomyelitis, poststroke, and in chronic fatigue syndrome. Disorders of neuromuscular junction transmission and metabolic diseases cause muscle fatigability, which is characterised by failure to sustain the force of muscle contraction (peripheral fatigue). Fatigue is also seen in diseases that affect the central, peripheral, and autonomic nervous systems (central fatigue). Enhanced perception of effort and limited endurance of sustained physical and mental activities are the main characteristics of central fatigue. Metabolic and structural lesions that disrupt the usual process of activation in pathways interconnecting the basal ganglia, thalamus, limbic system, and higher cortical centre are implicated in the pathophysiological process of central fatigue. A state of pre-existing relative hypocortisolaemia might sensitise the hypothalamic-pituitary-adrenal axis to development of persistent central fatigue after stress. The contributions of physiological, cognitive, and affective changes underlying fatigue are variable, and treatment is largely symptomatic and rehabilitative.     

Timolol treatment in the irritable bowel syndrome

The overall effect of the beta-blocker timolol maleate was not significantly different from placebo in patients with the irritable bowel syndrome on a high fibre diet. However, all 3 symptom-free patients were on timolol maleate. If beta-blockers have a major role to play in the treatment of the irritable bowel syndrome it must be through a central rather than a peripheral effect.     

正压通气治疗睡眠呼吸暂停综合征并代谢综合征的研究

目的：研究持续气道内正压通气（CPAP）对睡眠呼吸暂停综合征（SAS）并代谢综合征（MS）的疗效。方法：158例SAS并MS患者被随机分成两组，即CPAP治疗组（治疗组）和药物治疗组（对照组），治疗组在药物组治疗基础上加用CPAP治疗。两组患者于治疗前、治疗4周后分别行呼吸睡眠监测：动脉血氧饱和度（SaO2）、呼吸参数，并测空腹血糖（FPG）、空腹胰岛素（FINS）、餐后2h血糖（2hPG）、餐后2h胰岛素（2hPINS）、胰岛素敏感性指数（ISI）、总胆固醇（TC）、甘油三酯（TG）、高密度脂蛋白胆固醇（HDL-C）、体重指数（BMI）、收缩压（SBP）、舒张压（DBP）的变化。结果：与对照组比较，治疗组治疗后呼吸暂停和低通气均明显减少，打鼾消失，低氧发作次数减少，最低SaO2明显提高（P〈0．01）；同时血糖、胰岛素、TC、TG浓度，SBP、DBP均明显降低，HDL-C水平明显升高，与对照组比较有明显差异（P〈0．01）。结论：CPAP治疗SAS并MS除能改善SAS病情外，还能加强药物疗效，改善代谢参数，降低血压，降低心脑血管病危险因素的程度。