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Biomedical subjects

S Redline

Publications and source records attributed to S Redline.

At least 37 records · Page 2Linked to original sources
PubMed1999

Obstructive Sleep Apnea/Hypopnea Syndrome.

Obstructive sleep apnea/hypopnea (OSA/H) is a common disorder for which there are a variety of therapeutic options. All patients should make appropriate alterations in lifestyle and habits to reduce the risk of upper airway instability during sleep. The aggressiveness of additional treatment should be dictated by the severity of OSA/H, as measured by the condition's physiologic and clinical impact. At this time, the most compelling reason to treat patients with OSA/H is to reverse daytime sleepiness, functional or performance impairments, and clinically significant hypoxemia. Given data that suggest strong associations between vascular diseases and OSA/H, however, it may be prudent to use a relatively low threshold when deciding whether to treat patients at high risk for hypertension and cardiovascular diseases. Although we do not completely understand the extent to which any given derangement in sleep architecture or sleep-associated gas exchange leads to short- or long-term morbidity, such an abnormality should alert the clinician to the possible need for intervention and the need for careful follow-up. In general, all patients with OSA/H who require treatment should have a trial of continuous positive airway pressure (CPAP), the medical therapy of choice. This approach provides rapid and assured alleviation of OSA/H. Once CPAP therapy is under way, the patient and clinician can evaluate other options if the patient does not wish to continue long-term positive-pressure therapy. It is essential that patients and their caregivers understand the nature of OSA/H and its risk factors and realize that successful upper airway stabilization by means of medical and surgical interventions other than positive pressure or tracheostomy cannot be guaranteed. Surgical techniques cannot guarantee cure and can cause notable adverse consequences. Although it is almost invariably successful in maintaining upper airway patency during sleep, positive-pressure therapy may also have side effects. These generally are not lasting or severe, but they may nonetheless affect patient comfort. Measures are available to address these side effects. Increasing amounts of information support the importance to clinical care of patient education about both OSA/H and its therapy. Such education enhances the likelihood of successful treatment, improved quality of life, and improved long-term outcome.

Journal Article↗
PubMed1999

Recognition and consequences of obstructive sleep apnea hypopnea syndrome

There is a growing recognition of sleep-disordered breathing (SDB) in patient groups and in the general population. This article reviews issues related to recognizing the disorder, including the problems of relying on narrowly defined polysomnographic data for case findings and for assessment of disease severity. The distributions of symptoms and physiologic measurements of SDB in the population and their inter-relationships are reviewed. The epidemiological data that address risk factors and consequences of sleep apnea hypopnea syndrome (SAHS) also are discussed, with recommendations regarding recognition priorities.

Journal Article↗
PubMed1999

Risk factors for sleep-disordered breathing in children. Associations with obesity, race, and respiratory problems.

This study examined risk factors for sleep-disordered breathing (SDB) in children and adolescents; specifically, quantifying risk associated with obesity, race, and upper and lower respiratory problems. Subjects were participants in a genetic-epidemiologic study of SDB and included 399 children and adolescents 2 to 18 yr of age, recruited as members of families with a member (a proband) with known sleep apnea (31 index families) or as members of neighborhood control families (30 families). SDB was assessed with home overnight multichannel monitoring and SDB was defined based on an apneahypopnea index >/= 10 (moderately affected) or < 5 (unaffected). SDB of moderate level was significantly associated with obesity (odds ratio, 4.59; 95% confidence interval [CI], 1.58 to 13.33) and African-American race (odds ratio, 3.49; 95% CI, 1.56 to 8.32) but not with sex or age. After adjusting for obesity, proband sampling, race and familial clustering, sinus problems and persistent wheeze each independently (of the other) predicted SDB. These data suggest the importance of upper and lower respiratory problems and obesity as risk factors for SDB in children and adolescents. Increased risk in African Americans appears to be independent of the effects of obesity or respiratory problems.

Adolescent↗
PubMed1998

Reliability of scoring respiratory disturbance indices and sleep staging.

STUDY OBJECTIVES: Unattended, home-based polysomnography (PSG) is increasingly used in both research and clinical settings as an alternative to traditional laboratory-based studies, although the reliability of the scoring of these studies has not been described. The purpose of this study is to describe the reliability of the PSG scoring in the Sleep Heart Health Study (SHHS), a multicenter study of the relation between sleep-disordered breathing measured by unattended, in-home PSG using a portable sleep monitor, and cardiovascular outcomes. DESIGN: The reliability of SHHS scorers was evaluated based on 20 randomly selected studies per scorer, assessing both interscorer and intrascorer reliability. RESULTS: Both inter- and intrascorer comparisons on epoch-by-epoch sleep staging showed excellent reliability (kappa statistics >0.80), with stage 1 having the greatest discrepancies in scoring and stage 3/4 being the most reliably discriminated. The arousal index (number of arousals per hour of sleep) was moderately reliable, with an intraclass correlation (ICC) of 0.54. The scorers were highly reliable on various respiratory disturbance indices (RDIs), which incorporate an associated oxygen desaturation in the definition of respiratory events (2% to 5%) with or without the additional use of associated EEG arousal in the definition of respiratory events (ICC>0.90). When RDI was defined without considering oxygen desaturation or arousals to define respiratory events, the RDI was moderately reliable (ICC=0.74). The additional use of associated EEG arousals, but not oxygen desaturation, in defining respiratory events did little to increase the reliability of the RDI measure (ICC=0.77). CONCLUSIONS: The SHHS achieved a high degree of intrascorer and interscorer reliability for the scoring of sleep stage and RDI in unattended in-home PSG studies.

Humans↗
PubMed1998

Methods for obtaining and analyzing unattended polysomnography data for a multicenter study. Sleep Heart Health Research Group.

This paper reviews the data collection, processing, and analysis approaches developed to obtain comprehensive unattended polysomnographic data for the Sleep Heart Health Study, a multicenter study of the cardiovascular consequences of sleep-disordered breathing. Protocols were developed and implemented to standardize in-home data collection procedures and to perform centralized sleep scoring. Of 7027 studies performed on 6697 participants, 5534 studies were determined to be technically acceptable (failure rate 5.3%). Quality grades varied over time, reflecting the influences of variable technician experience, and equipment aging and modifications. Eighty-seven percent of studies were judged to be of "good" quality or better, and 75% were judged to be of sufficient quality to provide reliable sleep staging and arousal data. Poor submental EMG (electromyogram) accounted for the largest proportion of poor signal grades (9% of studies had <2 hours artifact free EMG signal). These data suggest that with rigorous training and clear protocols for data collection and processing, good-quality multichannel polysomnography data can be obtained for a majority of unattended studies performed in a research setting. Data most susceptible to poor signal quality are sleep staging and arousal data that require clear EEG (electroencephalograph) and EMG signals.

Electroencephalography↗
PubMed1998

Recognition and consequences of obstructive sleep apnea hypopnea syndrome.

There is a growing recognition of sleep-disordered breathing (SDB) in patient groups and in the general population. This article reviews issues related to recognizing the disorder, including the problems of relying on narrowly defined polysomnographic data for case findings and for assessment of disease severity. The distributions of symptoms and physiologic measurements of SDB in the population and their inter-relationships are reviewed. The epidemiological data that address risk factors and consequences of sleep apnea hypopnea syndrome (SAHS) also are discussed, with recommendations regarding recognition priorities.

Adult↗
PubMed1998

Improvement of mild sleep-disordered breathing with CPAP compared with conservative therapy.

The aim of this randomized controlled trial was to assess the effects of treatment with continuous positive airway pressure versus conservative therapy (CT) on well-being, mood, and functional status in subjects with mild sleep-disordered breathing (SDB). One hundred and eleven subjects, aged 25 to 65 yr, with a respiratory disturbance index (RDI) of 5 to 30 and without subjective pathologic sleepiness, were randomized to nasal CPAP or to CT. Ninety-seven subjects were followed-up after 8 wk. Treatment response was assessed from changes between baseline and follow-up measures of mood, energy/fatigue, and functional status/general health. Of the 51 subjects randomized to CPAP, 25 (49%) experienced an improved outcome, as compared with 12 of 46 of subjects (26%) randomized to CT (p < 0.05). The odds of experiencing a treatment response in the CPAP as compared with the CT group were 2.72 (OR: 1.18 to 6.58, 95% CI). A beneficial effect of CPAP over CT was most evident among individuals without sinus problems and among subjects with hypertension or diabetes. Differential treatment responses were not related to degree of baseline sleepiness or SDB. This suggests that middle-aged snorers with relatively low levels of SDB (RDI < 30) may benefit more from nasal CPAP than from less specific therapy directed at improving breathing during sleep. CPAP therapy may be beneficial to a broader group of subjects than previously appreciated.

Activities of Daily Living↗
PubMed1997

Characteristics of inner-city children with asthma: the National Cooperative Inner-City Asthma Study.

Asthma morbidity has increased dramatically in the past decade, especially among poor and minority children in the inner cities. The National Cooperative Inner-City Asthma Study (NCICAS) is a multicenter study designed to determine factors that contribute to asthma morbidity in children in the inner cities. A total of 1,528 children with asthma, ages 4 to 9 years old, were enrolled in a broad-based epidemiologic investigation of factors which were thought to be related to asthma morbidity. Baseline assessment included morbidity, allergy evaluation, adherence and access to care, home visits, and pulmonary function. Interval assessments were conducted at 3, 6, and 9 months after the baseline evaluations. Over the one-year period, 83% of the children had no hospitalizations and 3.6% had two or more. The children averaged 3 to 3.5 days of wheeze for each of the four two-week recall periods. The pattern of skin test sensitivity differed from other populations in that positive reactions to cockroach were higher (35%) and positive reactions to house dust mite were lower (31%). Caretakers reported smoking in 39% of households of children with asthma, and cotinine/creatinine ratios exceeded 30 ng/mg in 48% of the sample. High exposure (> 40 ppb) to nitrogen dioxide was found in 24% of homes. Although the majority of children had insurance coverage, 53% of study participants found it difficult to get follow-up asthma care. The data demonstrate that symptoms are frequent but do not result in hospitalization in the majority of children. These data indicate a number of areas which are potential contributors to the asthma morbidity in this population, such as environmental factors, lack of access to care, and adherence to treatment. Interventions to reduce asthma morbidity are more likely to be successful if they address the many different asthma risks found in the inner cities.

Allergens↗
PubMed1997

Hypopnea, a floating metric: implications for prevalence, morbidity estimates, and case finding.

The respiratory disturbance index (RDI) is the most frequently used metric to characterize sleep-disordered breathing. Clinically, the RDI is used to classify disease status and guide treatment decisions. For research purposes, the RDI is used to describe population distributions of sleep-disordered breathing. Its popularity as a cardinal disease-defining measure, however, may not be justified given that standardized criteria do not exist for defining hypopnea, a key component of the RDI. This paper reviews sources of variability in identifying hypopneas, including: the magnitude of changes in breathing amplitude necessary to describe breathing as "reduced" (from "discernible" to >50%), variations in the utilization of sensors with different sensitivities to detect airflow/ventilation (i.e. thermocouples, thermistors, and pressure transducers), and differential use of data on oxygen saturation and arousals to discriminate normal breathing from hypopneas. The extent to which disparate approaches influence the overall RDI and population estimates of disease also is discussed.

Adult↗
PubMed1997

Neuropsychological function in mild sleep-disordered breathing.

Although a broad range of neuropsychological deficits has been reported in patients with severe sleep disordered breathing (SDB), little is known about the impact of mild SDB on neuropsychological performance. In this study, we compared neuropsychological test performance in two groups of carefully screened volunteers who differed clearly according to the respiratory disturbance index (RDI). Controls (n = 20) were identified on the basis of an RDI < 5; cases (n = 32) had an RDI in the range of 10-30. Cases and controls were well matched with regard to IQ, age, and sex. Cases had significantly more self-reported snorting and apneas and a higher body mass index than controls but did not differ according to sleepiness as measured by either the multiple sleep latency test or the Epworth sleepiness scale. An extensive battery of neuropsychological and performance tests was administered after an overnight sleep study. Cases performed significantly more poorly on a visual vigilance task (perceptual sensitivity, d': 2.24 +/- 0.64 vs. 2.70 +/- 0.53, p = 0.01, for cases and controls, respectively) and a test of working memory, the Wechsler adult intelligence scale-revised digits backwards test (6.12 +/- 2.20 vs. 7.55 +/- 2.22, p = 0.02), than controls. The groups did not differ in their performance on other tests of memory, information processing, and executive functioning. In summary, subjects with mild SDB may manifest a vigilance deficit in the absence of substantial sleepiness. Subjects with a mildly elevated RDI (10-30) without sleepiness do not appear to suffer appreciable deficits in more complex neuropsychological processes (e.g. executive functions).

Cognition Disorders↗
PubMed1997

Racial differences in sleep-disordered breathing in African-Americans and Caucasians.

In this case-control family study of sleep-disordered breathing (SDB), we describe the distributions of SDB and SDB risk factors in African-Americans and Caucasians. A total of 225 African-Americans and 622 Caucasians, ages 2 to 86 yr, recruited as members of families with an individual with known sleep apnea (85 index families) or as members of neighborhood control families (63 families) were studied with an overnight home sleep-study, questionnaires, and physical measurements. A subsample underwent cephalometry. Outcome measures were the respiratory disturbance index (RDI) and a binary variable indicating the presence of increased apneic activity (IAA). In both races, a strong relationship was demonstrated between the (log transformed) RDI and age and age2. African-Americans with SDB were younger than Caucasians with SDB (37.2 +/- 19.5 versus 45.6 +/- 18.7 yr, p < 0.01). In subjects < or = 25 yr, RDI level and IAA prevalence were higher in African-Americans (odds ratio, adjusted for obesity, sex, proband sampling, and familial clustering, 1.88, 1.03 to 3.52, 95% CI). In this age group, racial differences also were observed in the relationship between RDI and age (p < 0.001 for the RDI-age interaction). This suggests that young African-Americans may be at increased risk for sleep apnea.

Adolescent↗
PubMed1997

Ventilatory-control abnormalities in familial sleep apnea.

The role of ventilatory-control abnormalities in predisposing to familial sleep-disordered breathing (SDB) was assessed in 31 subjects 28 +/- 10 yr of age (mean +/- SD). Subjects with (n = 10) and without SDB (n = 12) were recruited from 13 families having two or more members with SDB. Nine age- and gender-matched controls were recruited from families having no member with SDB. Respiratory responses to eucapnic hypoxia, and ventilatory and occlusion pressure responses to hyperoxic hypercapnia with and without added resistive loads (6.5 cm H2O/L/s), were assessed through rebreathing. Age, FEV1, and FVC did not differ among the groups. Hypoxic responses (delta VE/delta SaO2) were significantly lower among the first-degree relatives of SDB families than among controls (-0.76 +/- 0.47 L/min/% SaO2, and -1.32 +/- 0.92 L/min/% SaO2, respectively, p < 0.05). Respiratory responses to hypercapnia during unloaded conditions were similar among the groups. With resistive loading, inspiratory impedance, as measured through the relationship of mouth occlusion pressure (P100) to inspiratory flow (VT/TI), increased with increasing hypercapnia to a greater extent in members of SDB families than in controls (0.169 +/- 0.054 cm H2O/L/min versus 0.122 +/- 0.051, respectively, p < 0.05). These data suggest that familial SDB may be based partly on a familial abnormality in ventilatory control associated with blunting of the hypoxic ventilatory response. The greater increase in impedance during inspiratory loading in members of affected families also suggests a propensity for dynamic airway narrowing.

Adult↗
PubMed1997

An instrument to measure functional status outcomes for disorders of excessive sleepiness.

This article reports the development of the functional outcomes of sleep questionnaire (FOSQ). This is the first self-report measure designed to assess the impact of disorders of excessive sleepiness (DOES) on multiple activities of everyday living. Three samples were used in the development and psychometric analyses of the FOSQ: Sample 1 (n = 153) consisted of individuals seeking medical attention for a sleep problem and persons of similar age and gender having no sleep disorder; samples 2 (n = 24) and 3 (n = 51) were composed of patients from two medical centers diagnosed with obstructive sleep apnea (OSA). Factor analysis of the FOSQ yielded five factors: activity level, vigilance, intimacy and sexual relationships, general productivity, and social outcome. Internal reliability was excellent for both the subscales (alpha = 0.86 to alpha = 0.91) and the total scale (alpha = 0.95). Test-retest reliability of the FOSQ yielded coefficients ranging from r = 0.81 to r = 0.90 for the five subscales and r = 0.90 for the total measure. The FOSQ successfully discriminated between normal subjects and those seeking medical attention for a sleep problem (T157 = -5.88, p = 0.0001). This psychometric evaluation of the FOSQ demonstrated parameters acceptable for its application in research and in clinical practice to measure functional status outcomes for persons with DOES. Thus, the FOSQ can be used to determine how disorders of excessive sleepiness affect patients' abilities to conduct normal activities and the extent to which these abilities are improved by effective treatment of DOES.

Activities of Daily Living↗
PubMed1997

The Sleep Heart Health Study: design, rationale, and methods.

The Sleep Heart Health Study (SHHS) is a prospective cohort study designed to investigate obstructive sleep apnea (OSA) and other sleep-disordered breathing (SDB) as risk factors for the development of cardiovascular disease. The study is designed to enroll 6,600 adult participants aged 40 years and older who will undergo a home polysomnogram to assess the presence of OSA and other SDB. Participants in SHHS have been recruited from cohort studies in progress. Therefore, SHHS adds the assessment of OSA to the protocols of these studies and will use already collected data on the principal risk factors for cardiovascular disease as well as follow-up and outcome information pertaining to cardiovascular disease. Parent cohort studies and recruitment targets for these cohorts are the following: Atherosclerosis Risk in Communities Study (1,750 participants), Cardiovascular Health Study (1,350 participants), Framingham Heart Study (1,000 participants), Strong Heart Study (600 participants), New York Hypertension Cohorts (1,000 participants), and Tucson Epidemiologic Study of Airways Obstructive Diseases and the Health and Environment Study (900 participants). As part of the parent study follow-up procedures, participants will be surveyed at periodic intervals for the incidence and recurrence of cardiovascular disease events. The study provides sufficient statistical power for assessing OSA and other SDB as risk factors for major cardiovascular events, including myocardial infarction and stroke.

Adult↗
PubMed1996

Pre- and perinatal risk factors for asthma in inner city African-American children.

The relations between pre- and perinatal risk factors and asthma were investigated using a case-control study of 262 African-American children aged 4-9 years, both asthmatic and nonasthmatic, all of whom resided in a poor urban area and received health care at a local hospital-based clinic. Risk factors were ascertained through review of obstetric, perinatal, and pediatric records. Asthmatic children had significantly lower birth weights and gestational ages than nonasthmatic children and were more likely to have required oxygen supplementation and positive pressure ventilation after birth than nonasthmatics (p < 0.05). The mothers of asthmatic children were more likely to have smoked during pregnancy (50% vs. 27%), to have gained less weight during pregnancy (26.3 pounds (11.9 kg) vs. 34.5 pounds (15.7 kg)), and to have had no prenatal care (12% vs. 2% ) than mothers of nonasthmatic children. Multiple logistic regression demonstrated that the strongest independent predictors of asthma were maternal history of asthma (adjusted odds ratio (OR) = 9,7), lack of prenatal care (OR = 4.7), history of bronchiolitis (OR = 4.7), positive pressure ventilation at birth (OR = 3.3), low maternal weight gain (<20 pounds (<9 kg)) (OR = 3.4), and maternal smoking during pregnancy (OR = 2.8). These data suggest that pre- and perinatal exposures may increase susceptibility to asthma in inner city children.

Black or African American↗
PubMed1996

Short-term compliance with peak flow monitoring: results from a study of inner city children with asthma.

The objective of the study was to assess the feasibility of initiating daily peak flow monitoring in a research study of asthma in inner city children. We performed a descriptive study of patterns of peak flow monitoring in children randomized to receive a simple mini-Wright (SM) or an electronic recording meter (ERM). The ERM served as a "covert" meter, providing objective documentation of actual peak flow use. Sixty-five Hispanic or African-American children, ages 5-9 years, with a history of physician-diagnosed asthma participated in the study. All children resided in census tracts with 40% or more of the population living at or below the poverty level. Subjects were instructed to use a peak flow meter (the SM or ERM) at least twice daily over a 3 week period, and to record peak flow values in a paper diary. Subjects who received the ERM were not made aware that measurements were also recorded electronically. Differences in patterns of use of the SM and ERM were assessed with the Wilcoxon signed rank test and Wilcoxon sum rank test. Adherence to peak flow monitoring was evaluated by comparing the percent days with missing values in the manually completed diary with those obtained by computer record. The Friedman statistic was used to compare changes in compliance (percent of days with missing peak flow entries) over time. Accuracy of peak flow readings was assessed by comparing the manual and electronic recordings with paired and unpaired t-tests and with Pearson product moment correlations. The percent of days with missing peak flow entries on diaries increased from 1.4% to 10.6% from the first to third week of monitoring (P < 0.004). The ERMs indicated a significantly greater percent of missing data than did the manual records (P < 0.0002). The difference in the percent of missing data for the electronic and manual records was most notable during the third study week, when the ERM and the manually completed records indicated that 52% and 15% of days, respectively, were without peak flow measures. Large inter-subject variations in the relationship between manually and electronically recorded peak flow measurements were observed, suggesting that errors in reading and transcribing peak flow rates occur in a subset of asthmatics. We conclude that children and caretakers in the inner city may have considerable difficulty initiating and maintaining peak flow recordings. Data obtained by manual records may considerably overestimate actual use. Compliance with monitoring decreases markedly between the first and third week of monitoring.

Black or African American↗