Search PubMed⌕ Search

Biomedical subjects

T Gislason

Publications and source records attributed to T Gislason.

At least 55 records · Page 3Linked to original sources
PubMed1995

Snoring, apneic episodes, and nocturnal hypoxemia among children 6 months to 6 years old. An epidemiologic study of lower limit of prevalence.

STUDY OBJECTIVE: To identify a lower limit of the prevalence of sleep-related breathing disturbances among preschool children. DESIGN: A cross-sectional epidemiologic study in two stages, first by questionnaires and second by whole-night investigation of children symptomatic of the sleep apnea syndrome. SETTING: Gardabaer, a small town, 10 km south of Reykjavìk, Iceland. PARTICIPANTS: All children in Gardabaer, 6 months to 6 years old (n = 555). MEASUREMENTS: Symptom score estimated by questionnaire and respiratory events based on overnight oximetry, thermistors, and a static charge sensitive bed. RESULTS: The response rate was 81.8%. Snoring was reported as often or very often among 14 (3.2%) and occasionally by 73 (16.7%). Apneic episodes were reported often or very often among seven (1.6%). Altogether 18 children were highly suspected of the sleep apnea syndrome because of habitual snoring or apneic episodes. The girls (n = 9) were older than the boys (mean age: 46 +/- 21 months vs 20 +/- 12 months, p < 0.001). Eventually 11 children came for a whole-night investigation and 8 of them showed more than three respiratory events per hour of sleep, associated with > or = 4% oxygen desaturation. The lower limit of the sleep apnea syndrome prevalence among these children was thus 2.9% (SE, 0.5%). CONCLUSIONS: Among children, symptoms such as snoring and apneic episodes are reported relatively seldom, but a high proportion of the children with these symptoms have hypoxic respiratory events.

Child↗
PubMed1995

Continuous intrathoracic pressure monitoring with a new esophageal microchip catheter in sleep-related upper airway obstructions.

A new small-diameter microchip catheter, especially developed for continuous intrathoracic pressure monitoring to assess the degree of respiratory obstruction and effort in patients with sleep-related upper airway obstructions, was investigated. The technical performance and clinical applicability of the catheter was tested in a simplified screening study comprising 122 sleep recordings in patients with varying complaints of snoring and daytime tiredness. In six obese snorers, sensitivity of the catheter to apneas, hypopneas, and nonapneic snoring was compared to the traditional assessment of respiratory events by conventional polysomnography. The catheter was found to be easy to handle and introduce, with technical qualities meeting the demands for overnight recordings of intrathoracic pressure variations. Patient tolerance was high (93%), and sensitivity to apneas and hypopneas was equivalent to that of traditional polysomnography. Periods with upper airway obstruction and increased respiratory effort on the borderline between asymptomatic obstructions and obstructions resulting in significant blood-gas changes could be detected primarily with intrathoracic pressure monitoring. Monitoring the intrathoracic pressure variations in the esophagus has been shown previously to reflect respiratory effort. Increased respiratory effort might be one of the explanations for the fragmented sleep patterns and sleep related daytime symptoms sometimes seen in patients without a pathologic respiratory index. In addition to being applicable for the detection of apneas and hypopneas, continuous nocturnal monitoring of the intrathoracic pressure variations also detects small increases in respiratory effort and thus may constitute a valuable tool for the understanding and diagnosis of upper airway resistance syndrome and obstructive sleep apnea syndrome.

Adult↗
PubMed1995

Prevalence of sleep disturbances among young adults in three European countries.

The aim of this investigation was to study the geographic variation in sleep complaints and to identify risk factors for sleep disturbances in three European countries: Iceland (Reykjavik), Sweden (Uppsala and Göteborg) and Belgium (Antwerp). The study involved a random population of 2,202 subjects (age 20-45 years) who participated in the European Community Respiratory Health Survey. The subjects answered a questionnaire on sleep disturbances. Participants in Iceland and Sweden also estimated their sleep habits and sleep times during a period of 1 week in a sleep diary. Habitual (> or = 3/week) difficulties inducing sleep (DIS) were reported by 6-9% and early morning awakenings by 5-6% of the subjects. The estimated number of awakenings and the prevalence of nightmares was significantly lower in Reykjavik. Participants in Reykjavik went to bed at night and woke in the morning approximately 1 hour later than participants at the Swedish centers (p < 0.001). Symptoms of gastroesophageal reflux (GER) were associated with DIS (odds ratio [OR] = 2.7), nightmares (OR = 4.4), longer sleep latency and frequent nocturnal awakenings. Smoking correlated positively to DIS (OR = 1.8) and estimated sleep latency. We conclude that the prevalence of DIS was fairly similar at these four European centers but that there was a variation in the prevalence of nightmares and nocturnal awakenings. The significant correlation between reported GER and subjective quality of sleep should be followed up in studies using objective measurements.

Adult↗
PubMed1993

Snoring, hypertension, and the sleep apnea syndrome. An epidemiologic survey of middle-aged women.

The lower limit of the prevalence of sleep apnea syndrome (SAS) was estimated among women 40 to 59 years old by a two-stage procedure. In the first stage 2,016 questionnaires were mailed. The response rate was 75.6 percent. Daytime sleepiness was reported by 8.2 percent, habitual snoring by 11.2 percent, and intermittent snoring by 21.7 percent. There were altogether 128 women described with systemic hypertension and these women were more than twice as often habitual snorers. Logistic multiple regression analyses showed almost a threefold increase in the predicted prevalence of hypertension among intermittent and habitual snorers compared with nonsnorers in the age group 40 to 49 years old and a 60 percent increase in the 50- to 59-year-old age group. In the second stage, a group of 97 women highly suspected of SAS were selected because of their habitual snoring and daytime sleepiness. Eventually, 35 of these came for night studies and 14 were found to have SAS. Among the 35 women, 12 were hypertensive and nine of these had SAS. We estimated the lower limit of the prevalence of SAS to be 2.5 percent for women 40 to 59 years old. It is concluded that SAS is a relatively common occurrence among women, especially postmenopausal ones, and it is strongly related to hypertension.

Adult↗
PubMed1992

Substance P, thyrotropin-releasing hormone, and monoamine metabolites in cerebrospinal fluid in sleep apnea patients.

The cerebrospinal fluid (CSF) concentrations of thyrotropin-releasing hormone (TRH), substance P (SP), 5-hydroxyindoleacetic acid (5-HIAA), homovanillic acid (HVA), and 3-methoxy-4-hydroxyphenyl glycol (MHPG) were measured in 15 consecutive patients with the sleep apnea syndrome (SAS) and in healthy control subjects. Second measurements were performed 6 months after surgical treatment in 10 of the patients. The mean (+/- SD) concentration of TRH-like immunoreactive material (TRH-LIM) (pg/ml) did not differ significantly between patients with SAS (8.1 +/- 2.8) and control subjects (7.5 +/- 2.2). However, postoperatively, this concentration was increased in the six clinically cured patients with SAS, from 6.9 +/- 2.7 to 9.4 +/- 1.6 (p less than 0.03). Substance P-like immunoreactive material (SP-LIM) was higher in untreated patients with SAS than in control subjects: 19.2 +/- 6.7 versus 14.4 +/- 4.2 fmol/ml (p less than 0.02), and the level remained high after operation in the group treated surgically. The HVA, 5-HIAA, and MHPG concentrations were similar in patients with SAS and control subjects, and no consistent changes were found postoperatively. The CSF deviations in TRH-LIM and SP-LIM concentrations in the patients may reflect a primary central nervous system defect or they may be secondary to intermittent nocturnal hypoxia, progressive hypercapnia, and/or sleep fragmentation. In this sense, both these systems may be markers of SAS-SP as a "trait" marker and TRH as an indicator of the current state.

Adult↗
PubMed1992

Airway obstruction, obesity and CO2 ventilatory responsiveness in the sleep apnea syndrome.

In 32 patients with sleep apnea syndrome (SAS), pulmonary function, blood gases and the ventilatory response to CO2 (CO2 VR) were studied before and 6 months after uvulopalatopharyngoplasty. Nine of the SAS patients had airway obstruction (AO-SAS), defined as FEV1.0 < or = 72% of the predicted value. They had a significantly higher PaCO2, lower PaO2 and a lower CO2 VR than the remaining SAS patients. Preoperatively 4 SAS patients were hypercapnic (PaCO2 > 5.8 kPa) and compared with the normocapnic ones they were more obese; in 3 of them FEV1.0 was < or = 72%. The hypercapnic SAS patients had a significantly lower CO2 VR. The CO2 VR was significantly correlated to AO and the degree of oxygen desaturation during sleep, but not to the number of episodes of apnea and hypopnea nor their length. The VR to CO2 did not predict the postoperative outcome. Postoperatively 2 hypercapnic obese AO-SAS patients showed a large decrease in episodes of apnea and hypopnea and an increase in CO2 VR, and became normocapnic. Other patients showed no consistent changes in CO2 VR postoperatively.

Adult↗
PubMed1991

Sleep disturbances in asthma: theophylline versus enprofylline.

A double-blind cross-over study was performed on 22 asthmatic patients receiving maintenance treatment with theophylline who, in a previous study, had reported sleep problems. In one of two three-week periods the theophylline medication was replaced by an equipotent dose of slow-release enprofylline. Analysis of sleep questionnaires answered after each treatment period, and sleep diaries filled in throughout the study, showed no significant differences in the quality of sleep between the treatments. Peak expiratory flow (PEF) in the morning did not differ between the treatment periods, but mean PEF in the evening was slightly higher (20 l/min) during theophylline treatment. It was concluded that replacement of theophylline by enprofylline did not improve the quality of sleep subjectively in this group of theophylline treated asthmatics. The results suggest that adenosine receptor antagonism may not be a significant cause of sleep disturbances in asthmatic patients who are receiving theophylline as maintenance treatment.

Adult↗
PubMed1990

Sleep disturbances in patients with asthma.

The prevalence of sleep complaints and sleep disturbances was studied prospectively in 98 consecutive adult asthmatic patients (mean age 45 years, 46% men) attending an out-patient clinic by means of questionnaires and sleep diaries. The results were compared with those from an age- and sex-matched group of 226 healthy individuals. The most common sleep disturbances among the asthmatic patients were early morning awakening (51%), difficulty in maintaining sleep (DMS; 44%) and daytime sleepiness (44%). With decreasing asthma control (i.e. increased number of acute asthmatic attacks) there was an increase of DMS, nocturnal wakefulness, nocturnal breathing problems and bronchodilator inhalations at night. A decrease in estimated sleep time (P less than 0.05) and increase in nocturnal wakefulness (P less than 0.05) was seen with decreasing daytime FEV1--measured as percentage of the predicted value (%FEV1). There was also significant correlation between increasing age and decreasing %FEV1 (P less than 0.01). Among the 26 patients who were only taking one oral bronchodilator, no definite difference regarding sleep quality was found between those treated with theophylline and those taking an oral beta 2-agonist. The prevalence rates of DIS, DMS and daytime sleepiness were about twice as high among the asthmatic patients than in the healthy population. It is concluded that impaired quality of sleep, with disturbed sleep during the night, early morning awakenings and daytime sleepiness, is common among patients with bronchial asthma.

Acute Disease↗
PubMed1989

Theophylline disturbs sleep mainly in caffeine-sensitive persons.

In order to study effects of theophylline on sleep, a randomised double-blind cross-over study with slow release theophylline vs. placebo was performed on 13 healthy male volunteers (mean age 24 years), eight of whom were considered caffeine-sensitive and five caffeine-insensitive. A sleep diary was filled in during the entire period. At the end of each 2 week study period a sleep questionnaire was filled in and a sleep recording was conducted. Seven of the eight caffeine-sensitive persons reported that their sleep was disturbed during the theophylline period, while none of the five caffeine-insensitive experienced any difference between the periods. Analysis of the sleep diaries (mean +/- SD) revealed a significant increase in sleep latency (16 +/- 11 vs 4 +/- 7 min) and decrease in sleep efficiency (95 +/- 3 vs 98 +/- 3%) among the caffeine-sensitive persons during the theophylline period compared with the placebo period, while no such difference was found among the caffeine-insensitive. We conclude that theophylline seems to disturb sleep mainly in caffeine-sensitive persons.

Caffeine↗
PubMed1989

Increased CSF opioid activity in sleep apnea syndrome. Regression after successful treatment.

The etiology of the SAS is unknown. To test whether endogenous opioids could be pathologically active in SAS, markers of opioid systems were measured in the CSF of 15 patients with SAS and in control subjects. Measured by receptor assay, the concentration of so-called fraction 1 opioid was higher in patients with SAS (3.0 +/- 1.5 pmol/ml; mean +/- SD) than in control subjects (1.1 +/- 0.5 pmol/ml) (p less than 0.01), whereas that of fraction 2 opioid was similar in the two groups. Beta-endorphin-like activity, measured by radioimmunoassay, was somewhat lower in patients with SAS (14.0 +/- 2.8 pmol/ml) than in control subjects (21.8 +/- 7.6 pmol/ml) (p less than 0.05). Six months after surgical treatment of the soft palate, new measurements were made in eight patients. Fraction 2 endorphin and beta-endorphin showed no consistent changes. A decrease in the level of fraction 1 from 4.1 +/- 1.5 pmol/ml to 2.3 +/- 1.0 pmol/ml (p less than 0.02) was noted in those six patients showing a successful clinical course. The data support the hypothesis that in SAS the opioid activity is increased.

Adult↗
PubMed1989

Transcutaneous CO2 monitoring in adults with sleep-related breathing disorders.

The accuracy of transcutaneous CO2 monitoring (PtcCO2) was studied in 22 subjects suspected of having sleep-related breathing disorders, by comparison with arterial CO2 measurements (PaCO2). At rest 40 simultaneous sets of PaCO2 and PtcCO2 were obtained. The mean PaCO2 (+/-SD) was 5.3 +/- 0.9 kPa and PtcCO2 was 5.7 +/- 1.0 kPa (r = 0.79). The ventilatory response to CO2 was evaluated by a CO2 rebreathing method, and simultaneous measurements of PaCO2, PtcCO2 and end-tidal PCO2 (PETCO2) were made every min. Both PaCO2 and PETCO2 increased more during the first min of CO2 rebreathing than PtcCO2 (p less than 0.001). Between 1 to 5 min after the start of rebreathing there were no significant differences between the three methods. During sleep there was an increase in PtcCO2 (by 0.1-0.3 kPa) with each apneic event, the magnitude of the increase depending on the length and distribution of these events. With repeated long apneas there was a cumulative increase in PtcCO2, especially during REM sleep. Continuous PtcCO2 monitoring proved useful in monitoring and diagnosing sleep-related breathing disorders.

Adult↗
PubMed1989

High ventilatory response to hypoxia in hypertensive patients with sleep apnea.

The ventilatory response to hypoxia (VRH) in relation to daytime arterial blood pressure was studied in 37 patients with the sleep apnea syndrome (SAS). The patients were divided into hypertensives (n = 16) and normotensives (n = 21). The hypertensive group had a significantly higher VRH (ventilatory increase 1.48 1/min BTPS per percent decrease in arterial oxygen saturation) than the normotensive group (0.69 1/min/%, P less than 0.01). The observed difference raises the question whether a high chemoreceptor sensitivity to hypoxaemia can contribute in causing arterial hypertension among cases with SAS.

Female↗
PubMed1988

Uvulopalatopharyngoplasty in the sleep apnea syndrome. Predictors of results.

A prospective study of 34 consecutive patients with the sleep apnea syndrome was undertaken to evaluate the effectiveness and complications of, and predictors of, results in a conservative type of uvulopalatopharyngoplasty (UPPP). At six months, 65% of the patients had a 50% or greater reduction in the number of apneas and hypopneas per hour (responders). The responders to UPPP were less severely affected preoperatively regarding apneas and hypopneas, the mean number of which (+/- SD) were 32.7 +/- 20.8 compared with 64.6 +/- 26.0. They also had a lower body mass index before UPPP (31.3 +/- 4.1 vs 36.0 +/- 7.0 kg/m2). Preoperative computed tomography and cephalometry indicated that the nonresponders had narrower upper airways. It is concluded that UPPP is the treatment of choice for mild to moderate sleep apnea syndrome, but not for severely affected, heavily overweight patients with an increased tongue width.

Adult↗
PubMed1988

Prevalence of sleep apnea syndrome among Swedish men--an epidemiological study.

The prevalence of the sleep apnea syndrome (SAS) among Swedish men 30-69 years old was estimated by a two-stage procedure. In the first stage, 4064 questionnaires were mailed to a random sample of a defined population in the municipality of Uppsala. The response rate was almost 80%; 15.6% of the responders were habitual snorers and 5.8% complained of daytime sleepiness. From these, a group of 166 men highly suspected of having SAS was selected. Eventually, 61 of these came for all-night polysomnographic studies, and 15 of these were found to have SAS. On this basis the lower limit of the prevalence of SAS was estimated to be as high as 1.3%. The majority of subjects with the syndrome were in the age group 50-59 years.

Adult↗
PubMed1988

Chest physiotherapy. Evaluation by transcutaneous blood gas monitoring.

Two respiratory physiotherapy methods were evaluated by analyzing changes in the transcutaneous partial pressure of CO2 (tcPCO2) in 15 patients with respiratory insufficiency. All were receiving continuous oxygen therapy and had CO2 retention. The physiotherapy methods compared were thoracic compression (TC) and positive expiratory pressure (PEP). The mean decrease (+/- SD) in tcPCO2 was the same with both methods, 0.6 +/- 0.4 kPa, but there were interindividual differences. This study indicates that both TC and PEP effectively decrease tcPCO2, although only temporarily in many cases. Continuous tcPCO2 monitoring is a useful clinical method for determining and teaching optimal respiratory therapy.

Aged↗
PubMed1988

Transcutaneous monitoring of oxygen tension during progressive hypoxia and sleep.

Transcutaneous O2 monitoring (PtcO2) was studied in 16 adult subjects suspected of having sleep-related breathing disorders, by comparison with arterial O2 measurements (PaO2). At rest the mean difference (+/- SD) between PaO2 and PtcO2 was 3.6 (+/- 1.5) kPa. During progressive hypoxia 74 simultaneous measurements showed a mean decrease in PtcO2 from the beginning to the end of the hypoxic tests of 6.6 (+/- 1.4) kPa for PtcO2 and 7.1 (+/- 1.5) kPa for PaO2. The decrease in PtcO2 was slower than that in PaO2 during the first minute (p less than 0.001), but for the whole hypoxic period there was no difference in the rate of decrease between the two methods. Continuous PtcO2 monitoring has been found useful in detecting respiratory abnormalities during sleep.

Adult↗
PubMed1988

Ear oximetry during progressive hypoxia.

The BIOX III Pulse oximeter for measuring arterial oxygen saturation (SaO2) was compared during rest and under progressively hypoxic conditions, with SaO2 values based on arterial blood samples. The measurements were performed in 16 subjects undergoing tests of ventilatory response to hypoxia, by a rebreathing method. For each individual subject, there was a linear response relationship (r = 0.99), while for all 126 comparative values the regression equation was: y = 0.83 X + 14.7 (r = 0.98). The observed ventilatory response was lower when the calculations were based on oximeter readings. We conclude that the oximeter has acceptable correlation between the BIOX III and SaO2 measurements for clinical use, especially when SaO2 is above 70%.

Adult↗