Characteristics of apneas and hypopneas during sleep and relation to excessive daytime sleepiness.
ABSTRACT One of the most important symptoms in patients evaluated for possible obstructive sleep apnea syndrome is excessive daytime sleepiness, but the measures of apnea severity and of sleepiness used most commonly have not generally shown strong associations. We explored whether information recorded during standard polysomnography, other than the overall rate of apneas and hypopneas per hour of sleep (AHI), might help explain the measured severity of sleepiness.
A clinical sleep laboratory in a university hospital
N = 1,146 patients evaluated for suspected sleep-disordered breathing with nocturnal polysomnograms and multiple sleep latency tests.
The AHI during supine sleep (recorded in a subgroup of n = 169 subjects), the rate of apneas (n = 1,146), and the rate of obstructive apneas (n = 1,146) were particularly useful in explaining variation in measured levels sleepiness; rates of hypopneas and central apneas were less useful (n = 1,146). In addition, the minimum recorded oxygen saturation (n = 1,097) was as important as the AHI to the level of sleepiness.
In an attempt to explain excessive daytime sleepiness among patients evaluated for sleep-disordered breathing, additional insight is provided by observation of supine sleep during polysomnography, by emphasis on apneas rather than hypopneas, by emphasis on obstructive rather than central events, and by consideration of the minimum oxygen saturation.
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ABSTRACT: Patients with obstructive sleep apnea/hypopnea syndrome (OSAHS), even those generally compliant with CPAP therapy, often intermittently discontinue CPAP. Examine the impact of CPAP withdrawal on sleep, sleep disordered breathing (SDB), and daytime function in subjects with varying severity of OSAHS. Forty-two subjects (26M/16 F) with OSAHS (AHI4% = 45.2 ± 35.5/h pretreatment) on CPAP for 4 months were evaluated on the second night of CPAP withdrawal. Sleep architecture, SDB indices, and subjective/objective daytime function were assessed pretreatment, on CPAP therapy, and after CPAP withdrawal. Comparisons were made between pretreatment and CPAP withdrawal for the entire group, and for subgroups of mild/moderate (AHI4% < 30/h, n = 22) and severe (AHI4% > 30/h, n = 20) SDB. Overall, and for mild/moderate subjects, SDB indices returned to pretreatment values on CPAP withdrawal but with fewer apneas and more hypopneas/RERAs. For severe SDB, the event frequency (AI, AHI4%, and RDI) was lower and O desaturation was improved on CPAP withdrawal. Across SDB severity, sleep architecture showed lower %REM (15.6% vs 12.9%, P = 0.009) on the CPAP withdrawal compared to pretreatment. Stanford Sleepiness Score, MSLT, and PVT measures were not significantly different between pretreatment and CPAP withdrawal. Over a wide range of SDB severity CPAP withdrawal results in recurrence of SDB, albeit with less severe O desaturation. Subjective/objective daytime function returned to pretreatment levels. Sleep architecture changes on CPAP withdrawal (acute SDB) may reflect reduced sleep pressure compared to pretreatment chronic SDB. Our data suggest detrimental effects of even brief withdrawal of CPAP in subjects with both mild and severe OSAHS. CITATION: Young LR; Taxin ZH; Norman RG; Walsleben JA; Rapoport DM; Ayappa I. Response to CPAP withdrawal in patients with mild versus severe obstructive sleep apnea/hypopnea syndrome. 2013;36(3):405-412.Sleep 01/2013; 36(3):405-12. DOI:10.5665/sleep.2460 · 5.06 Impact Factor
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ABSTRACT: OBJECTIVES: Sleep disturbances can impair alertness and neurocognitive performance and increase the risk of falling asleep at the wheel. We investigated the prevalence of sleep disorders among public transport operators (PTOs) and assessed the interventional effects on hypersomnolence and neurocognitive function in those diagnosed with obstructive sleep apnea (OSA). METHODS: Overnight polygraphy and questionnaire data from 101 volunteers (72 males, median age 48 range [22-64] years, 87 PTOs) employed at the Gothenburg Public Transportation Company were assessed. Treatment was offered in cases with newly detected OSA. Daytime sleep episodes and neurocognitive function were assessed before and after intervention. RESULTS: At baseline, symptoms of daytime hypersomnolence, insomnia, restless legs syndrome as well as objectively assessed OSA (apnea hypopnea index (AHI, determined by polygraphic recording)=17[5-46]n/h) were highly present in 26, 24, 10 and 22%, respectively. A history of work related traffic accident was more prevalent in patients with OSA (59%) compared to those without (37%, p<0.08). In the intervention group (n=12) OSA treatment reduced AHI by -23 [-81 to -5]n/h (p=0.002), determined by polysomnography. Reduction of OSA was associated with a significant reduction of subjective sleepiness and blood pressure. Measures of daytime sleep propensity (microsleep episodes from 9 [0-20.5] to 0 [0-12.5], p<0.01) and missed responses during performance tests were greatly reduced, indices of sustained attention improved. CONCLUSIONS: PTOs had a high prevalence of sleep disorders, particularly OSA, which demonstrated a higher prevalence of work related accidents. Elimination of OSA led to significant subjective and objective improvements in daytime function. Our findings argue for greater awareness of sleep disorders and associated impacts on daytime function in public transport drivers.Accident; analysis and prevention 12/2012; 51C:208-214. DOI:10.1016/j.aap.2012.11.014 · 1.65 Impact Factor
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ABSTRACT: Conventional scoring of sleep provides little information about the process of transitioning between vigilance-states. We used the state space technique to explore whether rats with chronic upper airway obstruction (UAO) have abnormal sleep/wake states, faster movements between states, or abnormal transitions between states. The tracheae of 22-day-old Sprague-Dawley rats were surgically narrowed to increase upper airway resistance with no evidence for frank obstructed apneas or hypopneas; 24-h electroencephalography of sleep/wake recordings of UAO and sham-control animals was analyzed using state space technique. This non-categorical approach allows quantitative and unbiased examination of vigilance-states and state transitions. Measurements were performed 2 weeks post-surgery at baseline and following administration of ritanserin (5-HT2 receptor antagonist) the next day to stimulate sleep. UAO rats spent less time in deep (delta-rich) slow wave sleep (SWS) and near transition zones between states. State transitions from light SWS to wake and vice versa and microarousals were more frequent and rapid in UAO rats, indicating that obstructed animals have more regions where vigilance-states are unstable. Ritanserin consolidated sleep in both groups by decreasing the number of microarousals and trajectories between wake and light SWS, and increasing deep SWS in UAO. State space technique enables visualization of vigilance-state transitions and velocities that were not evident by traditional scoring methods. This analysis provides new quantitative assessment of abnormal vigilance-state dynamics in UAO in the absence of frank obstructed apneas or hypopneas.PLoS ONE 05/2014; 9(5):e97111. DOI:10.1371/journal.pone.0097111 · 3.53 Impact Factor