Sleep
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Anesthetics, including propofol, depress the electroencephalogram (EEG) and neuronal activity in the midbrain reticular formation (MRF). Because propofol has anesthetic effects in the spinal cord, we hypothesized that it would indirectly depress EEG and MRF neuronal responses to noxious stimulation in part by a spinal cord action. ⋯ Propofol blunted the EEG response to noxious stimulation in part via a subcortical action.
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This study assessed the extent to which sleep-disordered breathing (SDB), difficulty initiating and maintaining sleep (DIMS), and excessive daytime sleepiness (EDS) were associated with impairment of quality of life (QoL) using the SF-36. Participants (n=5,816; mean age=63 years; 52.5% women) were enrolled in the nation-wide population-based Sleep Heart Health Study (SHHS) implemented to investigate sleep-disordered breathing as a risk factor in the development of cardiovascular disease. Each transformed SF-36 scale was analyzed independently using multiple logistic regression analysis with sleep and other potential confounding variables (e.g., age, ethnicity) included as independent variables. ⋯ Both DIMS and EDS were strongly associated with reduced QoL even after adjusting for confounding variables for both sexes. Findings suggest 1) mild to moderate SDB is associated with reduced vitality, while severe SDB is more broadly associated with poorer QoL, 2) subjective sleep symptoms are comprehensively associated with poorer QoL, and 3) SF-36 mean score profiles for SDB and sleep symptoms are equivalent to other chronic diseases in the U. S. general population.
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Collapsibility of the upper airways has been identified as an important pathogenic factor in obstructive sleep apnea (OSA). Objective measures of collapsibility are pharyngeal critical pressure (Pcrit) and resistance of the upstream segment (Rus). To systematically determine the effects of sleep stage and body position we investigated 16 male subjects suffering from OSA. ⋯ Comparing the different body positions Rus was only significantly higher in the lateral position during REM sleep (p<0.05). The results indicate that collapsibility of the upper airways is not mediated by sleep stages but is strongly influenced by body position. As a consequence lower nCPAP pressure is needed during lateral positions compared to supine positions.
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To prospectively study the utility of four clinical prediction models for either predicting the presence of obstructive sleep apnea (OSA, apnea-hypopnea index [AHI] > or = 10/hour), or prioritizing patients for a split-night protocol (AHI(3)20/hour). ⋯ The clinical prediction models tested are not be sufficiently accurate to discriminate between patients with or without OSA but could be useful in prioritizing patients for split-night polysomnography.
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Randomized Controlled Trial Comparative Study Clinical Trial
A long-term randomized, cross-over comparison of auto-titrating and standard nasal continuous airway pressure.
This study is a 12-week randomized, cross-over, single-blind comparison of the tolerance, compliance, and symptomatic improvement obtained with standard nasal continuous positive airway pressure (CPAP) vs. an auto-titrating, self-adjusting device (APAP). Sixty newly diagnosed patients, 53 with obstructive sleep apnea (OSA) and seven with upper airway resistance syndrome were studied. Thirty-nine patients (65%) completed the 24-week protocol. ⋯ A higher proportion of patients who did not complete the study was randomized to CPAP for their initial treatment period. This study showed that: 1) CPAP and APAP produced an equivalent improvement in daytime sleepiness, 2) APAP pressure was lower than CPAP pressure, 3) patients wore the APAP device longer during nights they used the pressure support system, and 4) patients who began the study with APAP were more prone to continue treatment. We conclude that APAP was better tolerated and used a greater number of hours than CPAP, but the extent of improvement in excessive daytime sleepiness was similar between the two modes of therapy.