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Query: UMLS:C0037315 (sleep apnea)
 8,000 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

This article provides an in-depth overview of the relationship between primary hypertension and adult obstructive sleep apnea syndrome. The background data and research are taken from the English-language literature through 1993. Primary hypertension is a common cause of major medical illnesses, including stroke, heart disease, and renal failure, in middle-aged males. Its prevalence in the United States is around 20%, with the rate of newly diagnosed hypertensive patients being about 3% per year. Sleep apnea syndrome is common in the same population. It is estimated that up to 2% of women and 4% of men in the working population meet criteria for sleep apnea syndrome. The prevalence may be much higher in older, non-working men. Many of the factors predisposing to hypertension in middle age, such as obesity and the male sex, are also associated with sleep apnea. Recent publications describe a 30% prevalence of occult sleep apnea among middle-aged males with so called "primary hypertension." Is this association fortuitous, related to a high prevalence of both diseases in the same population, or is it caused by a factor common to both diseases, such as obesity? Should the diagnosis of apnea be actively sought with sleep studies in hypertensive populations? If a diagnosis of "asymptomatic" sleep apnea is made in a hypertensive person, should the apnea be treated? Current research data provide only partial answers to these and other questions regarding the association of apnea and hypertension. Logic dictates that clinically symptomatic patients in hypertensive clinics should receive appropriate evaluation for apnea, but broad populations of hypertensive individuals should not be referred for sleep studies.
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PMID:The relationship between systemic hypertension and obstructive sleep apnea: facts and theory. 784 28

Complaints about sleep and daytime alertness are common in ESRD patients. Eight consecutive ESRD patients with a sleep complaint were studied with all-night polysomnography. All were found to have significant sleep apnea with a mean apnea/hypopnea index (AHI) of 64 +/- 41.6 episodes per hour of sleep (range 7.5 to 140/hr of sleep). The majority of apneas were of the central or mixed variety causing severe fragmentation of sleep and frequent awakenings. Treatment was attempted with nasal continuous positive airway pressure (NCPAP). NCPAP was highly successful in six of the eight patients, reducing the mean AHI to normal or near normal levels (6.0 +/- 3.8/hr of sleep, P < 0.02 vs. baseline). The quality of sleep was significantly improved with statistically significant decreases in light stage 1 sleep, and nocturnal oxygenation improved with statistically significant increases in low SaO2 values. Five of six responders reported that they awoke feeling more alert and fewer times from sleep. The etiology of sleep apnea in ESRD is unknown although the frequent central apneas suggest a dysfunction of central respiratory control resulting from the effects of renal failure. Sleep-related complaints in patients with ESRD are likely to result from sleep apnea, a sleep disorder that can be diagnosed with polysomnography and treated with NCPAP.
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PMID:Sleep disordered breathing in ESRD: acute beneficial effects of treatment with nasal continuous positive airway pressure. 851 Mar 93

This study was proposed to define early and long-term results of coronary artery bypass grafting (CABG) in dialysis-dependent renal failure (RF) patients, and preoperative patient characteristics. This study included 105 patients (87 males and 18 females; mean age 60.0 +/- 9.0 years, range 39-79) with RF on maintenance dialysis (hemodialysis 100, peritoneal dialysis 5) who underwent isolated CABG between August 1985 and April 2000. Postoperative follow-up was completed in 100% and averaged 3.1 years. There were 22 emergency and 2 re-CABG cases. Previous myocardial infarction (MI) was found in 55 patients (52%), and unstable angina was noted in 53 patients (50%). Diabetes mellitus was the cause of RF in 50 patients (48%; 24 patients required insulin). There was 1 case of single vessel disease, 31 cases of double vessel disease, 54 cases of triple vessel disease, and 19 cases of left main disease. Preoperative left ventriculography was performed in 92 patients (88%). Left ventricular ejection fraction (LVEF) was 48.3 +/- 15.8% (range 11-74%) and was 40% or less in 25 patients (27%). The mean number of distal anastomoses was 2.5 (range 1-5). Three patients received only vein grafts, but all were cases of emergency CABG. The remaining 102 patients (97%) received at least 1 arterial conduit. Among them, 64 patients received only arterial conduits, and 72 patients received 2 or more distal anastomoses with arterial conduits. Five patients (4.8%) died within 30 days after CABG (2 cardiac deaths and 3 noncardiac deaths), and 8 patients (7.6%) died beyond 30 days after CABG before discharge (all noncardiac deaths). The cause of 2 cardiac deaths was abrupt circulatory collapse during or after hemodialysis in patients with severe left ventricular dysfunction (LVEF; 11% and 28%) in the early postoperative period. The causes of 8 noncardiac deaths included infection in 4 and rupture of aortic aneurysm, stroke, sleep apnea syndrome, and mesenteric infarction. During the follow-up period, there were 29 late deaths (8 cardiac, 13 noncardiac, and 8 sudden death), 6 MIs, 13 percutaneous transluminal coronary angioplasty, and 1 re-CABG. The 5-year actuarial survival rate was 59.8%, the cardiac death-free rate was 83.0%, and the cardiac event-free rate was 62.4%. Although CABG in patients on hemodialysis is associated with high early and long-term mortality in terms of both cardiac and noncardiac deaths in proportion to the severity of the preoperative condition, long-term survival was still better than that of general dialysis patients. Meticulous perioperative management may be the key factor in the improvement of early results.
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PMID:Coronary artery bypass grafting in 105 patients with hemodialysis-dependent renal failure. 1131 55

Nocturnal hypoxemia secondary to sleep apnea has long been implicated as a cardiovascular risk factor in renal failure, but to date there is no study that links nocturnal hypoxemia to cardiovascular outcomes in end-stage renal disease. Fifty uremic patients on regular dialysis treatment without primary sleep apnea, pulmonary diseases, or other illnesses that may cause sleep apnea underwent pulse oximetry studies during night and were followed up for 32 mo. Average nocturnal SaO(2), minimal SaO(2), and the number of episodes of hypoxemia were similar in patients who died during the follow-up and in patients who survived, and none of these parameters predicted all-cause mortality. Average nocturnal SaO(2) was significantly lower (P = 0.006) in patients who had cardiovascular events during the follow-up (94.7 +/- 2.9%) than in event-free patients (97.1 +/- 1.3%). In a Cox model, average nocturnal SaO(2) was the second factor in rank explaining these outcomes. In this model a 1% decrease in average nocturnal SaO(2) was associated with a 33% increase in the incident risk of fatal and nonfatal cardiovascular events. Furthermore the risk of cardiovascular events was 5.05 times higher in patients with average nocturnal SaO(2) <95% (95% CI 1.61 to 15.86) than in those above this threshold (P = 0.005). This study adds weight to the hypothesis that nocturnal hypoxemia in dialysis patients represents an important cardiovascular risk factor.
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PMID:Nocturnal hypoxemia predicts incident cardiovascular complications in dialysis patients. 1185 78

Hypertrophic osteoarthropathy (HOA) is a condition that accompanies many seemingly unrelated diseases. It is commonly associated with various clinical conditions such as pregnancy, aging, pulmonary diseases, cancers, and other systemic illnesses. The condition has been attributed to various causes such as platelet abnormalities, hormonal disturbances, and cytokine dysfunction, but the exact underlying mechanism has been elusive. We propose a unifying hypothesis that activation of the adrenergic system is the common thread that links all of the disparate clinical associations of hypertrophic osteoarthropathy. In diseased states, autonomic stimulation may occur as a result of chemoreceptor activation in response to acidosis, hypoxia, or hypercapnia. Examples include sleep apnea, congestive heart failure, renal failure, and tumor-induced hypoxia. In this setting, clinical signs of HOA may be a marker of underlying autonomic dysfunction. Autonomic stimulation may also occur as a normal part of pregnancy or as an abnormal component of aging. The exact pathway linking adrenergic excess to HOA remains to be clarified, but a plausible scenario based on current molecular evidence is offered.
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PMID:Hypertrophic osteoarthropathy may be a marker of underlying sympathetic bias. 1523 3

Lung and kidney function are intimately related in both health and disease. Respiratory changes help to mitigate the systemic effects of renal acid-base disturbances, and the reverse is also true, although renal compensation occurs more slowly than its respiratory counterpart. A large number of diseases affect both the lungs and the kidneys, presenting most often with alveolar hemorrhage and glomerulonephritis. Most of these conditions are uncommon or rare, although three of them--Wegener's granulomatosis, systemic lupus erythematosus, and Goodpasture's syndrome--are not infrequently encountered by respiratory care clinicians. Respiratory complications of chronic renal failure include pulmonary edema, fibrinous pleuritis, pulmonary calcification, and a predisposition to tuberculosis. Urinothorax is a rare entity associated with obstructive uropathy. Sleep disturbances are extremely common in patients with end-stage renal disease, with sleep apnea occurring in 60% or more of such patients. The management of patients with acute renal failure is frequently complicated by pulmonary edema and the effects of both fluid overload and metabolic acidosis. These processes affect the management of mechanical ventilation in such patients and may interfere with weaning. Successful lung-protective ventilation in patients with acute lung injury and renal failure may require modification of hemodialysis in order to combat severe acidemia. Hemodialysis-related hypoxemia, which was once believed to be the result of pulmonary leukostasis and complement activation, is explained by diffusion of CO2 into the dialysate, with concomitant alveolar hypoventilation in the process of maintaining a normal P(aCO2). Like acute lung injury, renal failure is a common complication of critical illness. An increasing body of evidence also supports the notion that the kidneys, like the lungs, are susceptible to injury induced as a result of positive-pressure mechanical ventilation.
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PMID:Respiratory considerations in the patient with renal failure. 1656 95

Peripheral arterial disease in the legs represents a subset of atherosclerosis that manifests a particularly sinister profile. A predominance of sympathetic activity in the periphery favors the development of neurogenic atherosclerosis. Atherosclerosis may then produce flow derangements and decreased physical activity that serves to escalate sympathetic bias in a vicious cycle. Restoration of normal flow in peripheral arterial disease may not only produce local benefit due to improved perfusion, but also represent a gateway to correcting many systemic conditions that may at first glance appear unrelated but share a common etiology of autonomic dysfunction, such as gout, acute coronary syndromes, stroke, sleep apnea, arrhythmias, depression, erectile dysfunction, inflammation, hypercoagulability, sleep disorders, bowel dysfunction, renal failure, and aging.
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PMID:Peripheral arterial disease: a manifestation of evolutionary dislocation and feed-forward dysfunction. 1670 60

Nocturnal hemodialysis has been shown to improve sleep apnea in patients who receive conventional hemodialysis. It was hypothesized that nocturnal peritoneal dialysis (NPD) also is effective in correcting sleep apnea in patients who receive continuous ambulatory PD (CAPD). Overnight polysomnography (PSG) was performed in 46 stable NPD and CAPD patients who were matched for demographic and clinical attributes. The prevalence of sleep apnea, defined as an apnea-hypopnea index (AHI; or frequency of apnea and hypopnea per hour of sleep) > or =15, was 52% for NPD patients and 91% for CAPD patients (P = 0.007). The mean (+/-SD) AHI in NPD and CAPD patients was 31.6 +/- 25.6 and 50.9 +/- 26.4 (P = 0.025), respectively. For validation of the efficacy of NPD in alleviating sleep apnea, a fixed sequence intervention study was performed in which 24 incident PD patients underwent one PSG study during mandatory cycler-assisted NPD while awaiting their turn for CAPD training and a second PSG recording shortly after they were established on stable CAPD. The prevalence of sleep apnea was 4.2% during NPD and 33.3% during CAPD (P = 0.016). AHI increased from 3.4 +/- 1.34 during NPD to 14.0 +/- 3.46 during CAPD (P < 0.001). With the use of bioelectrical impedance analysis, total body water content was significantly lower during stable NPD than CAPD (32.8 +/- 7.37 versus 35.1 +/- 7.35 L; P = 0.004). NPD delivered greater reductions in total body water (-2.81 +/- 0.45 versus -1.34 +/- 0.3 L; P = 0.015) and hydration fraction (-3.63 +/- 0.64 versus -0.71 +/- 0.52%; P = 0.005) during sleep. Pulmonary function tests remained unchanged before and after conversion from NPD to CAPD. These findings suggest that NPD may have a therapeutic edge over CAPD in sleep apnea that is associated with renal failure as a result of better fluid clearance during sleep.
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PMID:Alleviation of sleep apnea in patients with chronic renal failure by nocturnal cycler-assisted peritoneal dialysis compared with conventional continuous ambulatory peritoneal dialysis. 1722 96

We report the case of a patient with chronic renal failure and primary hyperparathyroidism who developed nonhypercapnic central sleep apnea syndrome (CSAS), which was multifactorial in origin and attributed to metabolic factors. Given an inadequate response to oxygen therapy and continuous positive airway pressure (CPAP) revealed by several polygraph studies, the patient was treated with bilevel positive airway pressure ventilatory support. Three months after treatment commenced, a parathyroidectomy was performed and hemodialysis was initiated. At this point it was observed that the patient no longer experienced somnolence; moreover, polysomnography revealed partial improvement in the CSAS and normalization of ventilatory patterns on application of nasal CPAP at 7 cm H2O. We discuss the pathogenesis of CSAS associated with chronic kidney failure along with the treatment options and conclude that treatment should be customized due to the lack of predictability of patient response.
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PMID:[Treatment of central sleep apnea syndrome of multifactorial origin by home ventilatory support]. 1769 49

Patients with a blunted fall in nocturnal BP (known as non-dippers) have a high risk of micro- and macrovascular complications, particularly if they have hypertension, but also in normotensive patients with diabetes. A blunted fall in nocturnal BP reflects the high level of CV risk in these patients. ABPM data indicating an altered circadian BP rhythm reverse circadian BP profile should alert the physician to the potential risk of complications and should lead to efforts to treat hypertension effectively, especially at night, and to check for sleep apnoea syndrome, particularly in cases of resistant hypertension, or autonomic neuropathy (postural hypotension), a well known risk factor for cardiovascular (CV) events. Patients should be carefully screened for nephropathy. However, the definitions of "non-dipper" vary widely. Suitable treatments are poorly defined, but angiotensin-converting enzyme inhibitors (ACEi), diuretics, salt restriction and the maintenance of continuous positive airway pressure (CPAP) can be used as non-specific treatments. The efficacy of taking blood pressure-lowering drugs at bedtime rather than in the morning is still debated but deserves attention. In the diabetic population, brachial pulse pressure (PP) is an independent predictor of cardiovascular mortality, but not of all-cause mortality. It is also associated with complications of both type 2 and type 1 diabetes, this effect being stronger for nocturnal than for diurnal PP, and is strongly predictive of coronary heart disease in patients with type 2 diabetes. The stronger association between PP and age in diabetic than in non-diabetic populations suggests that diabetes accelerates vascular ageing. In patients with incipient nephropathy or overt renal failure, PP increases CV risk. However, misinterpretation could be related to confusion between brachial PP and central PP. The therapeutic implications of PP measurement remain poorly documented in diabetes.
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PMID:Should pulse pressure and day/night variations in blood pressure be seen as independent risk factors requiring correction or simply as markers to be taken into account when evaluating overall vascular risk? 1793 63


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