Continuous positive airway pressure for treatment of sleep apnoea.
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Humans↗
Biomedical subjects
O Polo
Publications and source records attributed to O Polo.
Classification of nasal inspiratory flow shapes by attributed finite automata.
In a significant proportion of individuals, the physiologic decrease of muscle tone during sleep results in increased collapsibility of the upper respiratory airway. At peak inspiratory flow, the pharyngeal soft tissues may collapse and cause airflow limitation or even complete occlusion of the upper airway (sleep apnea). While there are plenty of methods to detect sleep apnea, only a few can be used to monitor flow limitation in sleeping individuals. Nasal prongs connected to pressure sensor provide information of the nasal airflow over time. This paper documents a method to automatically classify each nasal inspiratory pressure profile into one without flow limitation or six flow-limited ones. The recognition of the sample signals consists of three phases: preprocessing, primitive extraction, and word parsing phases. In the last one, a sequence of signal primitives is treated as a word and we test its membership in the attribute grammars constructed to the signal categories. The method gave in practical tests surprisingly high performance. Classifying 94;pc of the inspiratory profiles in agreement with the visual judgment of an expert physician, the performance of the method was considered good enough to warrant further testing in well-defined patient populations to determine the pressure profile distributions of different subject classes.
Algorithms↗
Effect of short-term transdermal estrogen replacement therapy on sleep: a randomized, double-blind crossover trial in postmenopausal women.
OBJECTIVE: To evaluate the effect of estrogen replacement therapy on sleep architecture, arousals, and body movements. DESIGN: A 7-month, prospective, randomized, double-blind, placebo-controlled crossover trial. SETTING: Departments of obstetrics and gynecology and a university sleep center in Turku, Finland. PATIENT(S): Seventy-one postmenopausal women, 4 of whom were excluded and 5 of whom withdrew from the study; the final study group consisted of 62 women. INTERVENTION(S): Two periods of treatment with either estrogen or placebo. MAIN OUTCOME MEASURE(S): Polysomnography for measurement of sleep and arousals and a static charge-sensitive bed for monitoring of movements and breathing. Self-reports of climacteric symptoms for 14 days. RESULT(S): Estrogen effectively alleviated hot flashes, sweating, sleep complaints, and headaches. Estrogen decreased the total frequency of movement arousals but increased alpha-arousals, especially during light non-rapid eye movement sleep (stage 1). Sleep latency, distribution of sleep stages, sleep efficiency, and total sleep time were similar during treatment with estrogen and placebo. Changes in serum E2 concentrations correlated with neither subjective nor objective sleep quality. CONCLUSION(S): Estrogen replacement therapy improves objective sleep quality by alleviating the frequency of nocturnal movement arousals. It also reduces climacteric symptoms, especially vasomotor symptoms. Estrogen replacement therapy does not seem to have any effect on sleep architecture.
Aged↗
Climacteric symptoms and sleep quality.
OBJECTIVE: To evaluate the effect of climacteric vasomotor symptoms on sleep quality measured by self-report and polysomnography in postmenopausal women. METHODS: Seventy-one healthy postmenopausal women were recruited, of whom 63 completed the study. Each subject recorded climacteric symptoms and subjective sleep quality for 14 days. Sleep quality was evaluated objectively by all-night polysomnography using the static charge-sensitive bed. RESULTS: During polysomnography, a high frequency of climacteric vasomotor symptoms was not associated with changes in sleep latency, percentage of sleep stages, number of arousals, sleep efficiency, or total sleep time. However, a high frequency of climacteric vasomotor symptoms (range 0-8.9, r = .60, P < .001), somatic symptoms (range 0-5.0, r = .25-.44, P < .05), and mental symptoms (range 0-5.0, r = .41-.51, P < .001) was related to impaired subjective sleep quality. In stepwise regression analysis, 32% of the impairment in subjective sleep quality was explained by vasomotor symptoms (P < .001), 14% by palpitations (P < .001), and 4% by mood instability (P = .029). High body mass index predicted impaired objective sleep quality, such as prolonged latencies to stage-2 sleep (r = .27, P = .031) and slow-wave sleep (r = .51, P = .003) and decreased oxygen saturations (r = -.54, P < .001). Older women had decreased sleep efficiency (r = -.27, P = .030) and lower oxygen saturations (r = -.36, P = .004). Serum estradiol level had only a minor effect on objective sleep quality. CONCLUSION: Impaired subjective sleep quality associated with climacteric vasomotor symptoms did not manifest as abnormalities in polysomnographic sleep recordings. Body mass index and age appeared to have the strongest effect on objective sleep quality.
Aged↗
Climacteric vasomotor symptoms do not imply autonomic dysfunction.
OBJECTIVE: To study whether oestrogen replacement therapy has an effect on autonomic haemodynamic control in postmenopausal women. DESIGN: A placebo-controlled, prospective, randomised, double-blind cross-over trial. POPULATION: Fourteen healthy postmenopausal women who had had a hysterectomy, of whom 12 were double-blind. METHODS: At the end of each treatment period we conducted autonomic nervous system tests: the Valsalva manoeuvre, the deep breathing test, study at rest and the active orthostatic test. Baroreflex sensitivity was evaluated non-invasively from the Valsalva manoeuvre. Heart rate variability was assessed in time and frequency domains during supine rest and standing. Serum oestradiol was also measured and the previous two weeks' symptoms were assessed. RESULTS: Autonomic nervous function was mostly normal for age and unchanged by oestrogen. Vasomotor symptoms were not associated with autonomic dysfunction. Baroreflex sensitivity was 13.3 ms/mmHg (SD 7.4 ms/mmHg) with placebo and 10.5 ms/mmHg (SD 5.4 ms/mmHg) with oestrogen (P = 0.052). This was mostly due to a fall in three of the highest indices. In the orthostatic test the 30 s blood pressure overshoot in two women exceeded the normal 90% confidence interval upper limit, making the mean response strong, especially in the symptomatic group (n = 7). Oestrogen attenuated this overshoot. CONCLUSIONS: Oestrogen did not have a consistent effect on the autonomic nervous system. Oestrogen attenuated a highly sensitive baroreflex and a strong 30 s blood pressure rise in the orthostatic test. This minor effect of oestrogen could be due to the fact that, in general, women with menopausal symptoms do not have impaired autonomic haemodynamic control. The effect of oestrogen in women with autonomic nervous system dysfunction remains to be studied.
Autonomic Nervous System↗
Respiratory insufficiency in postmenopausal women: sustained improvement of gas exchange with short-term medroxyprogesterone acetate.
STUDY OBJECTIVES: The degree and duration of respiratory stimulation of medroxyprogesterone acetate (MPA) in postmenopausal women. DESIGN: A placebo-controlled single-blind trial. SETTING: University hospital in Turku, Finland. PATIENTS: Fourteen postmenopausal women with permanent or previous episodic hypercapnic or hypoxemic respiratory failure. INTERVENTIONS: A 12-week trial including 14-day treatment periods with placebo and MPA (60 mg daily) and a 6-week follow-up. RESULTS: Thirteen of 14 patients completed the trial. The mean (+/- SD) PaCO2 at baseline was 42.8+/-4.5 mm Hg and the mean PaO2 was 71.2+/-9.0 mm Hg. The average reduction of PaCO2 was 6.3 mm Hg (14.7%, p < 0.001) on MPA and 3.0 mm Hg (6.1%, p = 0.001) after a 3-week washout. At 6 weeks after MPA, the PaCO2 had returned to baseline. The mean changes in PaO2 (+6.0+/-18.0 mm Hg on MPA and +3.8+/-22.5 mm Hg after a 3-week washout) were not significant. The PaO2/PaCO2 ratio increased, and bicarbonate and base excess decreased (p < 0.001) on MPA but not during washout. The systolic BP did not change on MPA but decreased on average 14.8+/-15.0 mm Hg (p = 0.016) after a 3-week washout. The diastolic BP remained unchanged. CONCLUSIONS: Our results suggest that postmenopausal women with chronic respiratory insufficiency consistently improve on MPA at a dose of 60 mg daily for 14 days. Lower PaCO2 is sustained for at least 3 weeks after cessation of MPA. The sustained effects in gas exchange and favorable after-effects in BP warrant further studies into the therapeutic efficacy and possible benefits of MPA pulse therapy.
Blood Gas Analysis↗
Serum estrogen level, attention, memory and other cognitive functions in middle-aged women.
OBJECTIVE: To evaluate the relationship between serum estradiol level and cognitive processing efficiency and memory. METHODS: Sixty-three healthy women aged 45-65 years were recruited through a newspaper announcement. The subjects were divided into two subgroups (low-estrogen group, n = 37 and high-estrogen group, n = 26) according to their serum follicle stimulating hormone (FSH) and estradiol levels. In the high-estrogen group, estrogen was either endogenous or supplied by estrogen replacement therapy. Automatic and controlled cognitive processing and attentional resources were measured using CogniSpeed software, together with conventional tests of cognitive performance: similarities, digit span, digit symbol, block design, object naming and recall, paired word associates (PWA) recall, Benton visual retention and paced auditory serial addition test (PASAT). The Beck depression inventory was also assessed. RESULTS: Cognitive reaction speeds were similar in both groups. Women with low estrogen levels made more errors in the vigilance test (sustained attention, p = 0.040). There were no differences in short-term or long-term memory, or verbal, visual or working memory between the study groups. Older women were slower in the ten-choice reaction time (10-CRT) test (r = 0.25, p = 0.047) and made more errors in the test of suppressing attention (Stroop incongruence test; r = 0.34, p = 0.007) and in the sustaining attention test (vigilance test; r = 0.47, p < 0.001). Depression scores did not correlate with cognitive variables. CONCLUSIONS: Cognitive performance was well preserved in healthy middle-aged women. Cognitive speed, accuracy, attentional resources and memory did not show impairment with decline of serum estrogen level in this age group.
Attention↗
[Eclampsia in Finland 1990-94].
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Eclampsia↗
When does estrogen replacement therapy improve sleep quality?
OBJECTIVE: Our purpose was to evaluate the effect of estrogen replacement therapy on sleep complaints by postmenopausal women and to assess the predictive factors involved. STUDY DESIGN: Sixty-three postmenopausal women entered a 7-month prospective, randomized, double-blind, crossover study consisting of two 3-month treatments with estrogen and placebo with a 1-month washout period between. Eight Visual Analogic Scale statements about different sleep complaints, the Basic Nordic Sleep Questionnaire, scoring of climacteric symptoms, The Beck Depression Inventory, and serum estradiol and follicle-stimulating hormone level controls were the main outcome measures. RESULTS: Estrogen replacement therapy improved sleep quality, facilitated falling asleep, and decreased nocturnal restlessness and awakenings (p < 0.001). The subjects were less tired in the mornings and in the daytime (p < 0.001) when taking estrogen replacement therapy. Estrogen-induced sleep improvement was associated with alleviation of vasomotor symptoms (r range 0.27 to 0.55), alleviation of somatic symptoms (palpitations and muscular pain, r range 0.26 to 0.36), and alleviation of mood symptoms (r range 0.28 to 0.37) on estrogen replacement therapy. The severity of initial insomnia predicted only one estrogen-induced sleep improvement effect: the more the subjects experienced insomnia, the better the estrogen replacement therapy facilitated falling asleep (r = 0.26, p = 0.040). Estrogen-induced sleep improvement was also reported by the 15 climacterically asymptomatic subjects. In these subjects initial insomnia scores strongly predicted estrogen-induced sleep improvement (r range 0.50 to 0.75). CONCLUSIONS: Estrogen replacement therapy significantly diminished sleep complaints among postmenopausal women. Alleviation of climacteric symptoms was the most important predictive factor for the beneficial effect of estrogen replacement therapy on sleep complaints. The use of estrogen replacement therapy in women without self-reported climacteric symptoms could also be considered because women do not always recognize their climacteric symptoms or they ignore them.
Climacteric↗
The effect of short-term estrogen replacement therapy on cognition: a randomized, double-blind, cross-over trial in postmenopausal women.
OBJECTIVE: To evaluate the effect of estrogen replacement therapy on cognitive functioning. METHODS: The study consisted of two 3-month treatment periods, one with estrogen and one with the placebo, in random order, separated by a 1-month wash-out period. The study group comprised 70 healthy postmenopausal women, aged 47-65 years, with previous hysterectomy. Sixty-two women completed the study. Cognitive speed and accuracy, attention, and memory were evaluated. Serum estradiol (E2) and FSH levels were controlled at the end of the estrogen, placebo, and wash-out periods. RESULTS: Most of the cognitive tests correlated with age: older women were slower and made more errors than younger women. Estrogen replacement therapy was not superior to the placebo in any test of cognitive performance. In two out of ten visual detection tasks, recognition thresholds were longer with estrogen than with the placebo (P < .001 and P = .004). On the most demanding test of working memory, the reaction times (P = .045) and error rates (P = .043) differed between treatments, yet this finding proved to be an effect of learning rather than treatment. There was no correlation between cognitive performance and serum E2 levels. CONCLUSION: Cognitive performance decreased with age. Short-term estrogen replacement therapy did not provide any advantage over the placebo in terms of improving the performance.
Aged↗
Nocturnal body movements and hypoxemia in middle-aged females after lower abdominal surgery under general anesthesia: a study with the static-charge-sensitive bed (SCSB).
OBJECTIVE: The aim of this study was to evaluate the feasibility of the static-charge-sensitive-bed (SCSB) combined with pulse oximetry (SpO2) for postoperative monitoring and to determine variables which could be used for evaluating the quality of postoperative sleep and breathing. METHODS: The frequency of body movements and the perioperative breathing abnormalities were assessed using the SCSB and pulse oximeter in 15 female ASA-class I-II patients undergoing elective lower abdominal surgery under general anesthesia. Anesthesia and control of postoperative pain followed standard practice. The patients were monitored during one preoperative and three consecutive postoperative nights. Movements were analyzed according to their duration and time interval. The effect of opioids was evaluated by measuring arterial oxyhemoglobin saturation (SpO2) with pulse oximetry for one hour before and two hours after administration of standard doses of oxycodone. RESULTS: The total movement time per hour increased during the first postoperative night (p = 0.003). Conversely, periodic movement activity decreased significantly during the three postoperative nights (p = 0.05, p < 0.001, p = 0.007). The mean SpO2 decreased during the first postoperative night (95.5% vs. 94.2%, p = 0.002), but returned to the preoperative level during the following nights. No episodes of apnea with significant oxygen desaturation (a decrease in SpO2 > 5%) were observed. Opioid administration was associated with decreased mean SpO2 (94.8% vs. 93.6%, p = 0.02), but did not lead to clinically significant hypoxemia (lowest observed SpO2 89.8%). CONCLUSIONS: Postoperative periodic movement activity was suppressed, but sleep remained fragmented with frequent body movements. In our middle-aged non-obese females (ASA I-II), no severe postoperative hypoxemia was observed during the three-nights postoperative survey. Perioperative movement monitoring with the SCSB was a valuable tool in rejecting movement artefacts of SpO2 and in evaluating general sleep quality.
Abdomen↗
Climacteric symptoms do not impair cognitive performances in postmenopause.
OBJECTIVE: To investigate whether information processing and attention performances are affected by climacteric vasomotor symptoms. METHODS: The study group comprised 66 healthy hysterectomized postmenopausal women. The subjects were divided into two subgroups (high symptomatic and low symptomatic) according to the quantity of climacteric vasomotor symptoms. Information processing was examined using CogniSpeed, a reaction time software that separates, for example, pure controlled processing and working memory from perceptual and motor components. Attention was examined by using visual and auditory tasks. The role of climacteric depression as a determinant of cognitive performance was evaluated by the Beck Depression Inventory and dividing subjects according to self-reported climacteric mood symptoms. The effects of serum oestrogen level and ageing on cognitive performances were also studied. RESULTS: Cognitive performances were similar in high symptomatic and low symptomatic women. On the Verification test younger women had shorter reaction times (P = 0.002) and on the Subtraction test they had fewer errors (P = 0.015) than older women. These tests required working memory and decision making. Accuracy in the tests of sustained and auditory attention worsened slightly with age. Cognitive performances neither correlated with scores on the Beck Depression scale nor with serum oestrogen level. Climacteric mood symptoms did not impair cognitive performance. CONCLUSIONS: Despite subjective complaints of memory impairment in association with climacteric vasomotor symptoms, our results did not support a direct cause-and-effect relationship. Thus, the minor deficits found in cognitive processing efficiency seem to be related rather to age than climacteric symptoms.
Aging↗
Digital fluoroscopy before and after laser uvulopalatopharyngoplasty in obstructive sleep apnea. Importance of pharyngeal collapsibility and hyoid bone position.
PURPOSE: To study the changes in pharyngeal behavior after laser uvulopalatopharyhgoplasty (LUPPP). MATERIAL AND METHODS: The dynamic changes in the upper airway size were evaluated with digital fluoroscopy in 24 patients with obstructive sleep apnea (OSA) before and after LUPPP and in 16 normal controls, while they were awake and breathing normally. Cephalometric measurements were also made. The patients were classified into the categories of good and poor responders by means of a static-charge-sensitive bed. RESULTS: Following LUPPP, collapsibility at the velopharyngeal level was within the normal range m 15 of 17 good responders, but only in 2 of 7 poor responders (p = 0.0086). The minimum airway size at the same level showed a similar trend. In 3 of 7 poor responders the hyoid bone was positioned more caudally than in the good responders (p = 0.017). CONCLUSION: Digital fluoroscopy provides information on the change in upper airway behavior after LUPPP.
Adult↗
The effect of laser-uvulopalatopharyngoplasty on the nasal and nasopharyngeal volume measured with acoustic rhinometry.
Nasal breathing is considered as an important factor in sleep apnea and snoring, and nasal obstruction can lead to an increased respiratory resistance and to inflammatory reactions in the nasal mucosa. Uvulopalatopharyngoplasty is an effective treatment for sleep apnea and snoring. Different operation techniques with minor variations have been introduced during the last few years. Uvulopalatopharyngoplasty with laser technique (LUPPP) has made it possible to perform the operation in local anesthesia. Acoustic rhinometry is a new method for the evaluation of the nasal cavities and the nasopharynx. We measured the volume of nasal cavities and nasopharynx of 29 patients using acoustic rhinometry before and 6 months after the LUPPP operation. There was a tendency to a better nasal patency in the turbinate area, but no change was found in the nasopharyngeal volume. Acoustic rhinometry is a useful tool for measuring the turbinate area, and this part of the nasal cavities seems to be influenced by the LUPPP operation, maybe due to a better ventilation or reduction of the inflammation of the nose. However, technical and methodological improvements are needed before reliable measurements are achieved from the nasopharynx area.
Acoustics↗
[Infant sleep apnea behind the life threatening cyanotic episodes, a good response to cpap treatment].
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Critical Illness↗
Sleep in multiple pregnancy: breathing patterns, oxygenation, and periodic leg movements.
OBJECTIVES: Our goal was to study whether multiple pregnancy at the third trimester predisposes to breathing disturbances and arterial oxyhemoglobin desaturation during sleep. STUDY DESIGN: Nocturnal breathing, oxygenation, and movement activity were studied in 10 mothers: 8 with twins, 1 with triplets, and 1 with quadruplets. RESULTS: No obstructive and few central sleep apnea episodes were observed. Four subjects had episodes of increased respiratory resistance, but only one, the mother with quadruplets, was significantly affected. Arterial oxyhemoglobin saturation was always maintained above 90%. Periodic leg movements were present in all mothers, with a frequency range of 3.7 to 49.7 movements per hour. CONCLUSIONS: In spite of the large uterus in multiple pregnancy, nocturnal breathing and oxygenation are well maintained. Increased motor activity and frequent awakenings suggest poor sleep quality, which may be further compromised by intensive periodic leg movements.
Adult↗
Respiratory and body movements as indicators of sleep stage and wakefulness in infants and young children.
Conventional polysomnographic (PSG) sleep staging to sleep staging based on a static-charge-sensitive bed (SCSB) recording in infants and young children was compared. The study consisted of whole-night clinical sleep studies in 22 children at 24 weeks (SD 24, range 1-79 weeks) of age. Most of the children presented with respiratory disturbances during sleep. From the SCSB record, sleep stages were differentiated according to regularity of breathing, presence of body movements, and most important, presence of high-frequency components of breathing (SCSB spikes). With both methods, three sleep/wake stages were distinguished: rapid eye movement (REM) sleep, non-rapid eye movement (NREM) sleep and wakefulness. The average interscorer reliability of the PSG sleep staging controlled in nine subjects was 88%. The average concordance between the two methods ranged from 82 to 85%, depending on the criteria used for scoring the SCSB. The mean sensitivity of the SCSB to detect NREM sleep ranged from 77 to 90% and the mean sensitivity to detect REM sleep ranged from 61 to 86%. The mean positive predictive value was 89-96% for NREM sleep and 54-67% for REM sleep. In conclusion, REM sleep is characterized by irregular breathing with superimposed fast respiratory movements. These changes are specific enough to allow distinction between episodes of NREM sleep, REM sleep and wakefulness with the non-invasive SCSB method in infants and young children. Incomplete concordance between PSG and SCSB score was most frequently observed during sleep stage transition periods, where the behavioural state and electrophysiological criteria disagreed. When combined with the PSG, the SCSB provides complementary information about the behavioural state of child.
Electroencephalography↗
Detection of periodic leg movements with a static-charge-sensitive bed.
We evaluated the performance of the static-charge-sensitive bed (SCSB), a non-invasive movement sensor, in detecting nocturnal periodic movement activity using simultaneous bilateral anterior tibialis electromyography (EMGat) as a reference. Two different study setups were used, one with 500 random record extracts, another with 10 continuous recordings. The inter-rater reliability between two independent scorers was 0.92 in scoring EMGat and 0.91 in scoring SCSB. In an epoch based analysis, depending on the study setup and scorer, the sensitivity of the SCSB to detect periodic leg movements was 0.81-0.94 whereas the specificity was 0.84-0.89. In a movement-by-movement analysis, despite incomplete concordance between the two methods the total number of movements per hour were comparable. Our findings support the use of the SCSB as a non-invasive alternative to anterior tibialis EMG recordings to reveal the presence of nocturnal periodic movement activity and estimate its frequency.
Adult↗