Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0037315 (sleep apnea)
 8,000 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Digoxin-like immunoreactive factor (DLIF) is an endogenous substance with natriuretic and diuretic activity. Elevated plasma levels of DLIF are found in various clinical states characterized by water and sodium retention. Chronic respiratory failure, particularly of an advanced stage, also is frequently associated with water and sodium retention. In order to determine whether elevated plasma levels of DLIF are present in chronic respiratory failure, we measured plasma DLIF levels in seven patients (four with COPD [two of whom had associated sleep apnea disturbance] and three with kyphoscoliosis) suffering from advanced chronic respiratory failure with severe hypoxemia and hypercapnia. We found that in these patients plasma levels of DLIF were significantly higher than in healthy control subjects. We conclude that patients with advanced chronic respiratory failure respond with increased levels of DLIF. This may represent an attempt at homeostasis of water and sodium metabolism which is frequently deranged in this clinical condition.
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PMID:Endogenous digoxin-like immunoreactive factor is elevated in advanced chronic respiratory failure. 130 96

A 57-year-old man was admitted complaining of sleep disturbance. All night polysomnography showed a pattern of obstructive sleep apnea. We performed 201Tl scintigraphy to evaluate hemodynamic change and degree of stress on the right ventricle during sleep, and compared it with a 201Tl scintigram during wakefulness. We recognized 201Tl uptake by the lung in the 201Tl scintigram during sleep, but not during wakefulness. To determine the mechanism of 201Tl uptake by the lung during sleep, we measured lung water content during sleep by double indicator dilution method (Nihon Koden, NTV-1100). We recognized an increase of lung water content during sleep. We consider that the increase of lung water content during sleep is caused by sleep apnea, probably by hemodynamic change due to negative pleural pressure swings during sleep apnea.
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PMID:[A case of obstructive sleep apnea syndrome with increased lung water content during sleep]. 140 80

Previous investigators have demonstrated in patients with obstructive sleep apnea that weight reduction results in a decrease in apnea severity. Although the mechanism for this decrease is not clear, we hypothesize that decreases in upper airway collapsibility account for decreases in apnea severity with weight loss. To determine whether weight loss causes decreases in collapsibility, we measured the upper airway critical pressure (Pcrit) before and after a 17.4 +/- 3.4% (mean +/- SD) reduction in body mass index in 13 patients with obstructive sleep apnea. Thirteen weight-stable control subjects matched for age, body mass index, gender (all men), and non-REM disordered breathing rate (DBR) also were studied before and after usual care intervention. During non-REM sleep, maximal inspiratory airflow was measured by varying the level of nasal pressure and Pcrit was determined by the level of nasal pressure below which maximal inspiratory airflow ceased. In the weight loss group, a significant decrease in DBR from 83.3 +/- 31.0 to 32.5 +/- 35.9 episodes/h and in Pcrit from 3.1 +/- 4.2 to -2.4 +/- 4.4 cm H2O (p less than 0.00001) was demonstrated. Moreover, decreases in Pcrit were associated with nearly complete elimination of apnea in each patient whose Pcrit fell below -4 cm H2O. In contrast, no significant change in DBR and a minimal reduction in Pcrit from 5.2 +/- 2.3 to 4.2 +/- 1.8 cm H2O (p = 0.031) was observed in the "usual care" group. We conclude that (1) weight loss is associated with decreases in upper airway collapsibility in obstructive sleep apnea, and that (2) the resolution of sleep apnea depends on the absolute level to which Pcrit falls.
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PMID:Effect of weight loss on upper airway collapsibility in obstructive sleep apnea. 189 85

The effects of incremental application of nasal continuous positive airway pressure (0 to 15 cm H2O) on heart rate, pulmonary artery pressure, and cardiac index were studied noninvasively by Doppler echocardiography. By two-way analysis of variance within two groups (19 normal volunteers and six sleep apnea patients), no significant effects on heart rate, pulmonary artery pressure, ventricular size, or cardiac index could be found with increasing positive intrathoracic pressures and consequent lung hyperinflation. In subjects with normal cardiac function, nasal CPAP is safe from a hemodynamic viewpoint. This simple, repeatable and noninvasive technique may be used to assess the clinical safety and efficacy of prescribed nasal CPAP on cardiac hemodynamics in individual patients.
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PMID:Hemodynamic effects of nasal CPAP examined by Doppler echocardiography. 198 89

Abnormalities in pharyngeal function, manifested even when the patients are awake, are thought to play an important role in the pathogenesis of sleep apnea. Tests of awake pharyngeal function continue to stimulate interest because it is hoped that they may allow physicians to distinguish patients with sleep apnea from those without it, and therefore reduce the number of unnecessary sleep studies. We elected to study two measures of pharyngeal function: changes in pharyngeal area with lung volume (PLVD) and changes in pharyngeal area in response to externally applied positive pressure, i.e., pharyngeal distensibility (Cph). Both measurements have been employed for assessment of pharyngeal function, and both are thought to reflect pharyngeal "floppiness." Measurement of PLVD is technically very simple, whereas the measurement of Cph is technically more complex. If the two measurements are highly correlated, it might be possible to replace the technically more difficult one by the simpler one. Consequently, the purpose of this study was two-fold: first, to examine the relationship between pharyngeal distensibility and lung volume dependence of pharyngeal area, and second, to compare these parameters in a large group of confirmed snorers with and without obstructive sleep apnea (OSA). We studied 75 unselected patients referred for the investigation of snoring and suspected sleep apnea. All patients had nocturnal polysomnography, pulmonary function tests, and measurement of pharyngeal areas at TLC, FRC, and residual volume (RV) employing the acoustic reflection technique. The area measurement at FRC was performed at zero and at 4.1 cm H2O positive airway pressure to calculate pharyngeal distensibility.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Pharyngeal function and snoring characteristics in apneic and nonapneic snorers. 204 16

1. It has recently been shown that obstructive sleep apnoea (OSA) patients have increased urinary water and salt excretion during sleep which tends to normalize with nasal continuous positive airway pressure (CPAP) treatment. 2. To investigate the mechanisms of these changes in renal function, nocturnal urinary excretion of catecholamines and guanosine 3':5'-cyclic monophosphate (cyclic GMP), which reflects atrial natriuretic factor (ANF) release, and next-morning plasma active renin concentrations were studied in 21 OSA patients on 2 consecutive nights, either untreated or treated with nasal CPAP. 3. In keeping with previous results, fractional urine flow and fractional Na+ and Cl- excretions were higher during untreated than during CPAP-treated nights. 4. No difference in plasma active renin concentration or in urinary excretion of noradrenaline, adrenaline, free dopamine and total dopamine could be demonstrated, but cyclic GMP excretion was significantly higher during untreated than during CPAP-treated nights. 5. The data are consistent with the hypothesis that the increased water and salt excretion in OSA patients is due to increased ANF release. 6. The proposed mechanism is an atrial distension due to increased (more negative) intrathoracic pressures during ineffective inspiratory efforts against the occluded upper airways which have been found in OSA.
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PMID:Urinary excretion of guanosine 3':5'-cyclic monophosphate during sleep in obstructive sleep apnoea patients with and without nasal continuous positive airway pressure treatment. 253 3

We studied five patients with chronic stable congestive heart failure (CHF), all of whom demonstrated recurrent apneas in association with Cheyne-Stokes respiration (CSR) during sleep. All five patients had symptoms consistent with a sleep apnea syndrome. Nasal continuous positive airway pressure (NCPAP) was administered at 8 to 12.5 cm H2O to all patients during sleep. The number of apneas fell from (mean +/- SE) 60 +/- 12/h of sleep on the control night to 9 +/- 7/h of sleep (p less than 0.01) on the NCPAP night, whereas mean nocturnal SaO2 rose from 88 +/- 2% on the control night to 92 +/- 2% (p less than 0.025) while on NCPAP. This was associated with resolution of symptoms of sleep apnea. In addition, resting left ventricular ejection fraction (LVEF) as measured by radionuclide angiography (RNA) rose from 31 +/- 8% while off NCPAP to 38 +/- 10% (p less than 0.05) while on NCPAP. Furthermore, all five patients experienced marked improvement in symptoms of heart failure from functional classes III and IV (New York Heart Association Classification) prior to NCPAP therapy to class II after NCPAP therapy was instituted. We conclude that, in certain patients, CSR during sleep associated with chronic CHF constitutes a sleep apnea syndrome, which can be alleviated by NCPAP. In addition, NCPAP therapy may lead to a reduction in cardiac dyspnea and improvement in left ventricular function.
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PMID:Effect of nasal continuous positive airway pressure on sleep apnea in congestive heart failure. 269 Jul 5

The most common causes of hypoxic cor pulmonale are chronic bronchitis and emphysema. Although the clinical situation in some patients is characterized early by hypoxemia, oedema is rare in patients with an arterial pO2 above 60 mm Hg. The presence of oedema can be regarded as an unfavorable prognostic indicator. For many years, peripheral oedema had been considered an expression of congestive cardiac failure; it may be assumed, however, that neither right nor left ventricular failure is prerequisite to the development of oedema. Oedema formation can be attributed to excessive retention of salt and water or a redistribution of body water into the extracellular compartment. Hypercapnia and acidosis affect direct stimulation of renal hydrogen ion secretion. The resulting electrochemical imbalance is compensated by reabsorption of sodium. Hypercapnia and, in acute phases possibly, hypoxia lead to a fall in renal blood flow mediated by alpha-adrenergic stimulation through activation of the renin-angiotensin-aldosterone system. An increase in plasma ADH may also contribute to development of oedema. The development of cor pulmonale or respiratory insufficiency can be enhanced by nocturnal hypoventilation and hypoxia during sleep as well as by sleep apnoea. Nocturnal hypoxia, smoking and reduced oxygen tension in the relevant kidney cells responsible for erythropoietin release promote the occurrence of secondary polycythaemia. For treatment of acute exacerbations in cor pulmonale associated with infections bronchitis antibiotics such as amoxycillin and cotrimoxacol are drugs of first choice. While the use of digoxin is of doubtful value, the cautious administration of diuretics may bring symptomatic relief. In addition to physiotherapy, beta-2-selective bronchodilators and nebulized bronchodilator therapy can be useful; theophyllines dilate airways and increase cardiac output but they can cause arrhythmias and a deterioration of arterial blood gases in hypoxic patients. If the patient has been treated chronically with corticosteroids, the dosage will have to be incremented; if asthma is suspected, corticosteroid treatment is essential. Controlled oxygen therapy is the most important single therapy aimed at relief of severe arterial hypoxaemia. Oxygen should be titrated initially (for the first one or two days) to achieve an arterial tension of at least 48 mm Hg. Thereafter, the oxygen flow should be increased to yield an arterial tension in excess of 60 mm Hg during continued treatment for two to three weeks.(ABSTRACT TRUNCATED AT 400 WORDS)
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PMID:Hypoxic cor pulmonale: a review. 294 54

A syndrome of sleep apnoea may appear 15 to 29 years after acute anterior poliomyelitis (PAA). It is generally a mixed syndrome with an association of central type and obstructive apnoea in variable proportions. We report such a case occurring in a patient who had presented 30 years before with PAA, and presenting on this occasion with resting pulmonary artery hypertension, polycythaemia but without disturbance of blood gases. Treatment with positive pressure ventilation was given by the nasal route at 10 cm of water leading to an improvement with a significant decrease in the number and duration of apnoeic episodes and a disappearance of desaturation. The sleep apnoea syndrome (SAS) should be considered as a possible late sequel of PAA.
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PMID:[Sleep apnea syndrome: late sequela of poliomyelitis]. 318 71

Recreational diving is a popular sport, although human ability to stay in and under water is severely limited physiologically. An understanding of these limitations enhances safety and enjoyment of sports diving. Breath-hold diving involves head-out water immersion, apnoea and submersion, exercise, cold stress, and pressure exposure. Each of these components, by itself, elicits prominent and specific physiological effects. Combination of these factors produces a unique and interesting physiological response generally known as diving reflex. Humans display weak diving responses, but exhibit no oxygen conservation function. Nevertheless, application of diving-induced physiological changes is now finding its way into clinical practice. Apnoea, face immersion, and head-out water immersion all show promise of clinical application. There are several spin-offs from diving research worth noting. Diuresis, enhancement of cardiac performance, and redistribution of blood flow, all produced by head-out water immersion, have been shown to be clinically useful, besides providing physiological data useful to space travel. Results from investigations on apnoea have been shown to be relevant to the following: treating some forms of cardiac arrhythmias; understanding drowning, sudden infant death syndrome and sleep apnoea; and confirming hyperventilation as the major cause of drowning. In comparison to marine mammals, humans are poor divers because of severe physiological constraints which limit their breath-hold time, diving depth, and ability to conserve body heat. Although under special circumstances humans can achieve unusually long breath-hold time and reach exceptional depth with a single breath, the sustainable working time and depth are only about 1 minute and 5 metres, respectively. Hypothermia inevitably results in divers working in the ocean. Without thermal protection, the intolerable limit of 35 degrees C is reached within 30 minutes in winter (10 degrees C) water and within 60 to 90 minutes in summer. Nevertheless, effective harvest work can be performed by humans in the ocean, and recreational benefits enhanced when these physiological limitations are respected. An unusual circulatory state exists during head-out water immersion in that there is a sustained increase of stroke volume. This results in 30% increase in cardiac output when the subject is resting in thermal neutral water, indicating a substantial overperfusion for the oxygen requirement. Furthermore, animal experiments showed that the elevated blood flow is preferentially channeled to the liver, fat, and the organs in the splanchnic region.(ABSTRACT TRUNCATED AT 400 WORDS)
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PMID:Applied physiology of diving. 327 55


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