SEARCH · PubMed Health

Results for “OSA”

Explore indexed PubMed citations for clinical trials, systematic reviews and public health research. Read source abstracts and follow each citation to its original PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 91 records · Page 5Linked to original sources

PubMed2001

Respiratory impedance response to continuous negative airway pressure in awake controls and OSAS.

The aim of the study was to determine whether the response of respiratory impedance (Zrs) to decreasing levels of continuous negative airway pressure (CNAP) during wakefulness, differs in controls and subjects with obstructive sleep apnoea syndrome (OSAS). Zrs was measured by the forced oscillation technique (4-32 Hz) in 15 controls and 21 patients with OSAS (apnoea/hypopnoea index >20 per sleep hour) with normal lung function, in the basal state and with application of decreasing CNAP of -5, -10, and -15 hPa. Respiratory resistance was extrapolated to 0 Hz (R0) and estimated at 16 Hz (R16) by linear regression analysis of respiratory resistive impedance versus frequency. Respiratory elastance (Ers) and inertance (Irs) were estimated by multilinear regression analysis of respiratory reactance versus frequency, and resonance frequency (RF) was determined as RF=(1/2pi)(Ers/Irs)0.5. In both groups, R0, R16, Ers and RF significantly increased as the CNAP level decreased (p <0.0001 for all). R0, Ers, and RF increased significantly more in OSAS than in controls (p < 0.01, 0.001, and 0.0001, respectively), independently of the severity of obesity. Receiver operator characteristic curves showed that the parameter which best detected OSAS was RF, with a sensitivity of 81% and 93% specificity for the 13.6 Hz cut-off point. The results of the present study suggest that the response of respiratory impedance to decreasing continuous negative airway pressure levels, might allow detection of obstructive sleep apnoea syndrome in subjects with normal lung function.

Adult↗

PubMed2001

Magnetic resonance imaging of the pharynx in OSA patients and healthy subjects.

Obstructive sleep apnoea (OSA) occurs because of recurrent narrowing and occlusion of the velopharynx (VP) during sleep. The specific cause of OSA is unknown. Cephalometric radiography, fibreoptic nasopharyngoscopy, acoustic reflection techniques, and computerized tomography have limitations (dynamic and tridimensional evaluation) in the mechanism of occlusion investigation. Static and dynamic examination of the soft tissue structures surrounding the upper airway during the respiratory cycle in wakefulness and sleep, can lead to a better understanding of the process. Ultrafast magnetic resonance imaging (one image per 0.8 s) was used to study the upper airway and surrounding soft tissue in 17 patients with OSA during wakefulness and sleep, and in eight healthy subjects whilst awake. The major findings of this investigation in the 25 subjects were as follows: 1) the VP was smaller in apnoeic patients, only during part of the respiratory cycle; 2) the variation in VP area during the respiratory cycle was greater in apnoeic patients than in controls, particularly during sleep, suggesting an increased compliance of the VP in these patients; 3) VP narrowing was similar in the lateral and anterior-posterior dimensions, both in controls and apnoeic patients while awake; apnoeic patients during sleep have a more circular VP upon reaching the minimum area; 4) there was an inverse relationship between dimensions of the lateral pharyngeal walls and airway area, probably indicating that lateral walls are passively compressed or stretched as a result of changes in the airway calibre; and 5) soft palate and parapharyngeal fatpads were larger in apnoeic patients, although their role in the genesis of OSA is uncertain. It was concluded that changes in the velopharynx area and diameter during the respiratory cycle are greater in apnoeic patients than in normal subjects, particularly during sleep. This suggests that apnoeic patients have a more collapsible velopharynx, this being the main mechanism of obstruction.

Adult↗

PubMed2005

Driving simulator and neuropsychological [corrected] testing in OSAS before and under CPAP therapy.

Patients with obstructive sleep apnoea syndrome (OSAS) have an increased car accident rate. Investigations on accident frequency are based on case history, insurance reports and driving simulator studies. The present study combines neuropsychological testing of different attention aspects engaged in driving a car and driving simulation to evaluate a suitable instrument for assessing therapeutic effects of continuous positive airway pressure (CPAP). Driving simulator investigation and neuropsychological testing of alertness, vigilance and divided attention were performed in 31 patients with polysomnographically confirmed OSAS (apnoea-hypopnoea index 24.8+/-21.5.h(-1)) before, and 2 and 42 days after initiation of CPAP. Divided attention and alertness improved significantly during CPAP, whereas vigilance remained unchanged. However, accident frequency (OSAS before therapy: 2.7+/-2.0; 2 days after CPAP: 1.5+/-1.4; 42 days after CPAP: 0.9+/-1.3) and frequency of concentration faults (OSAS before therapy: 12.4+/-5.1; 2 days after CPAP: 6.5+/-3.9; 42 days after CPAP: 4.9+/-3.3) decreased in the simulated driving situation after 2 and 42 days of therapy. There was no relation between accident frequency, concentration faults and daytime sleepiness, as measured by the Epworth Sleepiness Scale, and polysomnographic or neuropsychological findings, respectively. In conclusion, the present results suggest that driving simulation is a possible benchmark parameter of driving performance in obstructive sleep apnoea syndrome patients.

Accidents, Traffic↗

PubMed2006

Continuous positive airway pressure does not reduce blood pressure in nonsleepy hypertensive OSA patients.

Obstructive sleep apnoea (OSA) is associated with high cardiovascular morbidity and mortality. Several randomised controlled trials have shown that continuous positive airway pressure (CPAP) treatment of OSA reduces blood pressure (BP). This randomised, sham-placebo controlled crossover trial assesses whether CPAP produces a similar clinically significant fall in BP in hypertensive OSA patients, but without hypersomnolence. Thirty-five, nonsleepy, hypertensive patients with OSA were treated with CPAP for 1 month, randomised first to either therapeutic or sham-placebo (subtherapeutic CPAP, about 1 cmH(2)O pressure). The second months' alternative treatment followed a 2-week washout period. BP was measured over 24 h, before and at the end of the two treatment periods: mean 24-h BP was the primary outcome variable. There was no overall significant difference in mean 24-h BP: the change in mean 24-h BP on therapeutic CPAP was -2.1 mmHg (sd 8.1), and -1.1 mmHg (sd 8.1) on subtherapeutic CPAP, with a difference of 0.7 mmHg (95% confidence interval (CI) +2.9- -4.4). There was a small significant fall in Epworth Sleepiness Score, therapeutic (-1.4) versus sham (-0.3), and difference -1.2 (95% CI -2.0- -0.4), but no change in objective sleepiness. In nonhypersomnolent hypertensive patients with obstructive sleep apnoea, there is no significant fall in mean 24-h blood pressure with continuous positive airway pressure, in contrast to the fall seen in hypersomnolent patients with obstructive sleep apnoea.

Adult↗

PubMed2006

Performance of a color-difference formula based on OSA-UCS space using small-medium color differences.

An investigation of the color metrics and the complexity of the CIEDE2000 formula shows that CIELAB space is inadequate to represent small-medium color differences. The OSA-UCS (Uniform Color Space) Committee has shown that no space with uniform scale for large color differences exists. Therefore the practical way for color-difference specification is a color-difference formula in a nonuniform space. First, the BFD (Bradford University) ellipses are considered in the OSA-UCS space, and their very high regularity suggests a new and very simple color-difference formula at constant luminance. Then the COM (combined) data set used for the development of the CIEDE2000 formula is considered in the OSA-UCS space, and the color-difference formula is extended to sample pairs with a different luminance factor. The value of the performance factor PF/3 for the proposed OSA-UCS-based formula shows that the formula performs like the more complex CIEDE2000 formula for small-medium color differences.

Algorithms↗

PubMed1990

Overnight decrease in hematocrit after nasal CPAP treatment in patients with OSA.

To clarify the paradox of a decrease in urine and sodium excretion occurring along with the elimination of peripheral edema when patients with obstructive sleep apnea (OSA) are treated with nasal continuous positive airway pressure (CPAP), we investigated the immediate effects of this treatment on the hematocrit and red blood cell count in eight patients with OSA. The hematocrit decreased in all patients, from a mean of 45.6 +/- 1.2 percent to 43.0 +/- 1.4 percent, with a parallel decrease in the red blood cell count from 4.777 +/- 0.168 millions/cu mm to 4.577 +/- 0.174 millions/cu mm (p less than 0.0005, one-tailed, in both cases). These results suggest that nasal CPAP treatment causes a hemodilution in patients with OSA, and are compatible with the hypothesis of an atrial natriuretic peptide-induced fluid shift from the intravascular to the extravascular volume in untreated patients with OSA. The reversal of these changes with CPAP treatment could explain the simultaneous decrease in sodium and urine excretion and the reduction of peripheral edema.

Darkness↗

PubMed2000

[The variation of nasal obstruction in patients with OSAS].

OBJECTIVE: To study the variation of nasal resistance and its possible relationship to obstructive sleep apnea. METHODS: The detection of nasal resistance and polysomnography were performed in 30 normal subjects, 30 snoring patients and 60 patients with OSAS. RESULTS: The study reveal that nasal resistance of the patients with OSAS (1.06 +/- 4.25) Pa.s/ml, (2.29 +/- 9.74) Pa.s/ml or snoring (0.71 +/- 0.31) Pa.s/ml was higher than that of normal group (0.40 +/- 0.13) Pa.s/ml (P < 0.01). There was a positive correlation between nasal resistance and snoring index (r = 0.258, P < 0.01), but there was no correlation among AHI, waken intervals, and nasal resistance. CONCLUSION: Nasal resistance increased in the patients with snoring or OSAS, it may be a factor related with OSAS.

Adult↗

PubMed2001

[Atrial natriuretic excretion in patients with obstructive sleep apnea syndrome (OSAS)].

UNLABELLED: During obstructive sleep apneas stimuli, that may increase excretion of atrial natriuretic peptide (ANP) occur. The aim of the study was the evaluation whether in patients with OSAS levels of ANP are significantly different in relation to sleep or wakefulness and in relation to disturbances of ventilation during sleep and wakefulness. The material of the study consisted of 34 patients with OSAS (age 25-65 years). There were no differences in the levels of ANP late in the evening, during sleep and early in the morning. There were 2 groups of the patients: with low (< 70 pg/ml, mean at 21 p.m. 9.7 +/- 8.7 pg/ml, at. 2 a.m. 12.5 +/- 9.3 pg/ml, at 6 a.m. 14.4 +/- 15.1 pg/ml) and high (> 70 pg/ml, mean at 21 p.m. 148.6 +/- 232.9 pg/ml, at 2 a.m. 119.5 +/- 45.5 pg/ml, at 6 a.m. 164.9 +/- 161 pg/ml) ANP levels. As compared with patients with low ANP levels, patients with high ANP levels were older and more obese, more frequently had concomitant COPD, lower VC and FEV1, higher daytime PaCO2 and lower PaO2; most of them had peripheral edema. In patients with high ANP levels there was more profound mean arterial blood desaturation during sleep apnoeas than in patients with low ANP levels (SaO2 75 +/- 8% vs 81 +/- 4%, p < 0.001), although apnea index and mean apnea duration were similar in both groups. CONCLUSIONS: In patients with OSAS the daytime and sleep levels of ANP are similar. High levels of ANP can be found in OSAS patients with impaired daytime ventilation and gas exchange, and profound arterial oxygen desaturation during sleep apnoeas.

Adult↗

PubMed2005

[Treatment of OSAS with modified twin-block advancement appliances].

OBJECTIVE: To introduce a new modified twin-block advancement appliance and investigate the effects on respiratory variables in patients with OSAS. METHODS: 29 patients with OSAS participated in the study and were fitted with modified twin-block appliances to hold the mandible in an anterior and inferior position. Polysomnography was performed with and without appliance insertion. And questionnaires were used for registration of patients subjective symptoms. Pair-t analysis was used to evaluate the effects of appliances in patients with OSAS. RESULTS: 26 patients responded to the appliance therapy. Apnea-hypopnea index, apnea index and hypopnea index were reduced significantly (P < 0.01). Lowest arterial oxygen saturation improved significantly (P < 0.01). Discomfort with mandibular advancement disappeared within one week. CONCLUSIONS: Modified twin-block advancement appliance is a conservative, successful treatment alternative that could benefit patients suffered from OSAS.

Adult↗

PubMed2005

[OSAS and driving capacity].

Obstructive sleep apnea syndrome (OSAS) is a very frequent clinical problem, sleepiness being one important symptom. Car driving necessitates attention and concentration. That why OSAS patients are at high risk of having car crash. But more than 60% of these patients will never have a car crash. CPAP treatment is very efficient also to correct this risk. Despite utilisation of driving simulator, we are actually unable to detect, in the OSAS population, the individual who will have a crash. To diagnose OSAS very early and to treat efficiently remain the key of security.

Accidents, Traffic↗

PubMed2005

[Hyperuricaemia in males with obstructive sleep apnoea (osa)].

UNLABELLED: Previous studies showed that uric acid (UA) excretion in urine is increased in OSA patients and normalized after CPAP therapy. The aim of our study was to assess serum UA in a large group of males with OSA before treatment. METHODS: All subjects had full or limited PSG, measurements of serum uric acid, cholesterol, triglicerydes, glucose levels, lung function tests and medical history for cardiovascular diseases. RESULTS: We studied 260 consecutive, obese males (BMI = 33.1 +/- 6.2 kg/m2), mean age 51.5 +/- 9.9 years, with severe OSA (mean AHI/RDI = 44 +/- 24, mean overnight SaO2 = 89.2 +/- 5.4%, T90 = 43.8 +/- 34.4%. Hyperuricaemia (UA >7 mg%) was found in 56.2% of studied subjects. UA concentration correlated with obesity and overnight oxygenation. Multiple regression analysis revealed significant correlation between UA and BMI. Subjects with hyperuricaemia presented with higher prevalence of systemic hypertension, coronary artery disease, diabetes mellitus and COPD. CONCLUSIONS: Hyperuricaemia is frequent in males with OSA. Elevated UA levels are related to extreme obesity, overnight desaturation and higher prevalence of systemic hypertension, coronary artery disease, diabetes and COPD.

Body Mass Index↗

PubMed1990

Treatment of obese patients with obstructive sleep apnea syndrome (OSAS): effect of weight loss and interference of otorhinolaryngoiatric pathology.

The role of weight loss in the therapy of obstructive sleep apnea syndrome (OSAS) was investigated in 23 affected patients with various degrees of obesity (body mass index range 26.6-61.0) free of cranio-facial malformations. Weight loss resulted 18.5 +/- 14.7 (s.d.) kg and was significantly correlated with baseline BMI value (r = 0.94; P less than 0.0001). Weight loss significantly reduced the number of apneas + hypopneas per hour of sleep ((A + H)I) from 66.5 +/- 23.0 to 33.0 +/- 26.2 (P less than 0.0001) and improved the mean of oxygen desaturation peaks during apneas (mSaO2) from 81.9 +/- 6.9 to 87.6 +/- 3.9; P less than 0.001). A significant correlation was found between weight loss and changes in the (A + H)I (r = -0.55; P less than 0.01) and the mSaO2 (r = 0.46; P less than 0.05). The (A + H)I significantly improved in both patients who lost more than 10 kg (basal BMI: 42.3 +/- 10.0) and in those who lost less than 10 kg (basal BMI: 30.2 +/- 2.3), whereas the mSaO2 improved only in the former. Obese patients with moderate to heavy ORL pathological findings had worse pretreatment and final OSAS parameters than those with absent or mild ORL lesions. However, both groups showed a significant, although quantitatively different, improvement of the (A + H)I and mSaO2 after weight loss. Compared to those who were cured or improved after the treatment, patients who failed to obtain significant effects on OSAS clinical presentation also had a significantly higher prevalence of ORL pathology. It is concluded that: (1) weight loss improves parameters and clinical presentation of OSAS in the majority of affected obese patients; (2) a relationship exists between the entity of weight loss and that of improvement of the syndrome; (3) weight loss must be encouraged even in patients with mild to moderate overweight; (4) the presence of ORL pathology may represent a confusing factor in the interpretation of the results obtained after weight loss.

Adult↗

PubMed1998

[Comparative cephalometric study in patients with obstructive sleep apnea syndrome (OSAS), simple snorers and controls].

Lateral cranial teleradiography was carried out in 106 subjects, including obese and non-obese patients with obstructive sleep apnea syndrome (OSAS) and obese and non-obese healthy snorers and controls. In the OSAS patients alone, the hyoid bone occupied an abnormally low position, which pushed the tongue into a more vertical position. OSAS patients had the most voluminous soft tissues, followed by simple snorers and controls. Soft tissue volume generally was related with obesity. The pharyngeal airway space was widest in controls, intermediate in snores and narrowest in OSAS patients, except in the hypopharynx, where airway dimensions were similar in all the patients studied.

Adult↗

PubMed2004

Children with severe OSAS who have adenotonsillectomy in the morning are less likely to have postoperative desaturation than those operated in the afternoon.

PURPOSE: To determine, in a subset of children previously reported, if the time of day when adenotonsillectomy for severe obstructive sleep apnea syndrome (OSAS) was performed affected the incidence of postoperative respiratory complications. CLINICAL FEATURES: Children having adenotonsillectomy were included if they had a polysomnographic diagnosis of severe OSAS within six months prior to operation. Patients who met the inclusion criteria were grouped by the occurrence of postoperative desaturation into a saturated (SAT) and desaturated (deSAT) group. The charts of children in group deSAT were reviewed. The clock time of the surgical procedure was recorded and categorized as morning (AM) or afternoon (PM). RESULTS: Eighty-eight patients met the inclusion criteria. There were 31 girls and 57 boys. The mean +/- SD age (yr) and weight (kg) were 4.6 +/- 2.9 yr and 20.8 +/- 14.5 kg respectively. There were 63 children in the SAT group and 25 in the deSAT group. Differences in age, weight and gender were not significant. The preoperative oxygen saturation (SaO2) nadir for the SAT and deSAT groups was 80.8 +/- 10.2% and 67.6 +/- 17.5% (P < 0.05) respectively. The preoperative obstructive apnea and hypopnea index was 15.8 +/- 10.2 and 35.7 +/- 34.6 events.hr(-1) (P < 0.05), respectively. Surgery in 63 (71.6%) children was performed in the AM. Univariate logistic regression identified PM surgery [odds ratio (OR) 4.6, 95% confidence interval (CI) 1.7 to 12.6, P = 0.002] and a preoperative SaO2 nadir < 80% (OR 3.6, 95% CI 1.4 to 9.4, P = 0.009) as risk factors predicting postadenotonsillectomy desaturation. CONCLUSION: Children with severe OSAS whose surgery is performed in the AM are less likely to desaturate following adenotonsillectomy than children whose surgery is performed in the PM.

Adenoidectomy↗

PubMed2003

[Prevalence of obstructive sleep apnea syndrome (OSA) in patients with sudden hearing loss. A pilot study].

BACKGROUND: It is estimated that in patients with sleep-related breathing disorders the probability of a cerebral vascular infarction (CVI) is 3.1 times that in patients without sleep apnea and that 25-50% of all patients who have a stroke suffer from sleep apnea (OSA) and have a respiratory disturbance index (RDI) higher than 10. CVI may be caused by variations in intracranial pressure or in intracranial hemodynamics owing to decreasing pO(2) and increasing pCO(2) during cessation of airflow. It is suspected that the most common causes of sudden deafness are vasospasm, thrombosis, embolism, hypercoagulation and sludging. The present study analyzed the prevalence of sleep apnea in patients with sudden hearing loss. PATIENTS AND METHODS: A 7-channel polygraph was used to test 33 subjects with normal hearing and 27 patients suffering from sudden hearing loss. Statistical analyses were performed with a Chi-square test and the Mann-Whitney test. RESULTS: We found that 29.6% of the patient group and 21.2% of those in the study control group were suffering from OSA and had RDI >10; this difference was not significant ( p=0.554). Sudden hearing loss may also be an indicator of arteriosclerosis secondary to such risk factors as hypertension ( p=0.005), diabetes ( p=0.003), and hyperlipidemia ( p=0.004), which were highly significant for the patient group. CONCLUSION: Patients who develop sudden hearing loss tend to have OSA more frequently than those in the control group owing to the similar risk factors for cerebral infarction and sudden hearing loss.

Adolescent↗

PubMed2001

Cervical positioning for reduction of sleep-disordered breathing in mild-to-moderate OSAS.

The objective of this study was to assess whether cervical positioning could improve mild to moderate cases of the obstructive sleep apnea syndrome (OSAS). Eighteen subjects recruited from a tertiary sleep disorders clinic population with mild to moderate cases of OSAS were evaluated using a custom-fitted cervical pillow designed to increase upper airway caliber by promoting head extension. The subjects used their usual pillows during two consecutive recorded baseline nights in our laboratory. They then used the cervical pillow for 5 days at home and returned for 2 consecutive recorded nights at our laboratory to use the cervical pillow. During the nights in our laboratory, the subjects completed questionnaires, were videotaped to record head and body position, and had full polysomnography. The subjects had a significant trend toward improvement in their respiratory disturbance indices with use of the cervical pillow, despite spending more time in the supine position and having similar amounts of REM sleep in the baseline and experimental conditions. They also had nonsignificant trends toward improvements in their sleep efficiency and subjective depth of their sleep as well as significantly fewer arousals and awakenings in the experimental compared with the baseline condition. We propose that cervical positioning (i.e., head extension) with a custom-fitted cervical pillow provides a simple, noninvasive, and comfortable means of reducing sleep-disordered breathing in patients with mild to moderate OSAS.

Adolescent↗

PubMed2005

Effect of CPAP treatment on inspiratory arousal threshold during NREM sleep in OSAS.

The maximal inspiratory effort recorded at the end of apnea has been considered as an index of arousal threshold in obstructive sleep apnea syndrome (OSAS). Previous investigations have shown that the arousal threshold is higher in patients with OSAS than in normal subjects. The aim of the present study was to investigate the effect of continuous positive airway pressure (CPAP) treatment on the inspiratory-effort-related arousal threshold in patients with OSAS. In ten male patients, 40 episodes of apnea during stage 2 non-REM (NREM) sleep were analyzed. Apnea duration (t), esophageal pressure (Pes) at the first occluded breath (Pes1), the minimum of the three initial Pes swings (Pes min), the maximum of the three final Pes swings (Pes Max), DeltaPes (Pes Max-Pes min), RPes (rate of increase of intrathoracic pressure, DeltaPes/t), n (number of occluded breaths during apnea), DeltaPes/n, n/t, and SaO(2) were determined before and after occlusion. These apneic episodes were compared to ten episodes of apnea provoked by a mask occlusion device after 1, 7, 30, and 90 days of CPAP treatment. The therapy resulted in a decrease in the inspiratory-effort-related arousal threshold, as measured by a reduction of Pes Max, without significant changes in apnea duration and apnea-related hypoxemia. Pes1 and DeltaPes/n, which are markers of respiratory drive, significantly decreased between observations. CPAP treatment decreases the inspiratory-effort-related arousal threshold and induces a decrease in ventilatory drive in response to upper airway occlusion.

Arousal↗

PubMed2003

Long-term follow-up and mechanisms of obstructive sleep apnea (OSA) and related syndromes through infancy and childhood.

BACKGROUND: Although tonsil and adenoid (T&A) enlargement in children is a leading cause of it, Obstructive Sleep Apnea (OSA) may occur at any age. But even after T&A surgery, some children experience recurrent apneic episodes. The reasons for possible recurrence are unclear. OBJECTIVE: To quantify the prevalence of recurrent OSA after T&A surgery and find out a common cause of OSA in children from the neonatal period to adulthood. METHOD: A retrospective report of apneic patients followed in a tertiary-care center is presented. Telephone interviews of parents were performed 3 years after T&A surgery. The questionnaire included night and day symptoms related to sleep-disordered breathing (SDB). A literature review was performed about associated causes of upper airway stenosis. RESULTS: Out of 59 children who were included to follow up, 5 (8.5%) experienced residual or recurrent symptoms of SDB. The literature suggests the role of skeletal abnormalities in this process through nasal or pharyngeal stenosis. Major craniofacial anomalies are a well-known cause of obstruction. Thickened soft tissue has to be ruled out. Minor stenoses or neuromuscular disorders are less often diagnosed although they seem to be involved as well. CONCLUSION: A longitudinal follow-up of apneic children is able to reveal recurrence of SDB after adenotonsillectomy and often allows the understanding of mechanisms of upstream-induced recurrent pharyngeal obstructions.

Adolescent↗