Respiratory arousals in mild obstructive sleep apnea syndrome (original) (raw)
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Clinical predictors of the respiratory arousal threshold in patients with obstructive sleep apnea
American journal of respiratory and critical care medicine, 2014
A low respiratory arousal threshold (ArTH) is one of several traits involved in obstructive sleep apnea pathogenesis and may be a therapeutic target; however, there is no simple way to identify patients without invasive measurements. To determine the physiologic determinates of the ArTH and develop a clinical tool that can identify patients with low ArTH. Anthropometric data were collected in 146 participants who underwent overnight polysomnography with an epiglottic catheter to measure the ArTH (nadir epiglottic pressure before arousal). The ArTH was measured from up to 20 non-REM and REM respiratory events selected randomly. Multiple linear regression was used to determine the independent predictors of the ArTH. Logistic regression was used to develop a clinical scoring system. Nadir oxygen saturation as measured by pulse oximetry, apnea-hypopnea index, and the fraction of events that were hypopneas (Fhypopneas) were independent predictors of the ArTH (r(2) = 0.59; P < 0.001). ...
Arousal Intensity is a Distinct Pathophysiological Trait in Obstructive Sleep Apnea
SLEEP, 2016
Study Objectives: Arousals from sleep vary in duration and intensity. Accordingly, the physiological consequences of different types of arousals may also vary. Factors that influence arousal intensity are only partly understood. This study aimed to determine if arousal intensity is mediated by the strength of the preceding respiratory stimulus, and investigate other factors mediating arousal intensity and its role on post-arousal ventilatory and pharyngeal muscle responses. Methods: Data were acquired in 71 adults (17 controls, 54 obstructive sleep apnea patients) instrumented with polysomnography equipment plus genioglossus and tensor palatini electromyography (EMG), a nasal mask and pneumotachograph, and an epiglottic pressure sensor. Transient reductions in CPAP were delivered during sleep to induce respiratory-related arousals. Arousal intensity was measured using a validated 10-point scale. Results: Average arousal intensity was not related to the magnitude of the preceding respiratory stimuli but was positively associated with arousal duration, time to arousal, rate of change in epiglottic pressure and negatively with BMI (R 2 > 0.10, P ≤ 0.006). High (> 5) intensity arousals caused greater ventilatory responses than low (≤ 5) intensity arousals (10.9 [6.8-14.5] vs. 7.8 [4.7-12.9] L/min; P = 0.036) and greater increases in tensor palatini EMG (10 [3-17] vs. 6 [2-11]%max; P = 0.031), with less pronounced increases in genioglossus EMG. Conclusions: Average arousal intensity is independent of the preceding respiratory stimulus. This is consistent with arousal intensity being a distinct trait. Respiratory and pharyngeal muscle responses increase with arousal intensity. Thus, patients with higher arousal intensities may be more prone to respiratory control instability. These findings are important for sleep apnea pathogenesis.
Characteristics and Consequences of Non-apneic Respiratory Events During Sleep
Rationale: Current scoring criteria of non-apneic events (ie, hypopnea) require the presence of oxyhemoglobin desaturation and/or arousal. However, other sleep study parameters may help to identify abnormal respiratory events (REs) and assist in making more accurate diagnosis. Objectives: To investigate whether non-apneic REs without desaturation or cortical arousal are associated with respiratory and cardiac consequences. Methods: Thirteen participants with sleep disturbances (snoring and/or excessive day time sleepiness), were screened using attended in laboratory pol-ysomnography (PSG) while monitoring pressure and airflow via a nasal mask with an attached pneumotach. To separate the contribution of the upper airway resistance (R UA) and total pulmonary resistance (R L), supraglottic and esophageal pressures were measured using Millar pressure catheters. R L and R UA were calculated during baseline and hypopneas. R L was defined as the resistive pressure divided by the maximal flow during inspiration and expiration. Hypopnea was defined 30% decrease in flow with 3% desaturation and/or cortical arousal. REs was defined as 30% decrease in the flow without desaturation and/or cortical arousal. In eight subjects continuous positive airway pressure (CPAP) was titrated to optimal pressure. R-R interval (RRI) was defined as consecutive beat-to-beat intervals on single lead electrocardiograph (ECG) during baseline, RE/hypopnea and on optimal CPAP. Results: REs associated with increased expiratory R UA (14.6 ± 11.3 vs. 7.5 ± 4.5 cmH 2 O L −1 s −1 ; p < .05), and increased expiratory R L relative to baseline (29.2 ± 14.6 vs. 20.9 ± 11.0 and 23.7 ± 12.1 vs. 14.3 ± 5.6 cmH 2 O L −1 s −1 during inspiration and expiration, respectively; p < .05). RRI decreased significantly following RE and hypopnea relative to baseline (804.8 ± 33.1 vs. 806.4 ± 36.3 vs. 934.3 ± 45.8 ms; p < .05). Optimal CPAP decreased expiratory R UA (4.0 ± 2.5 vs. 7.5 ± 4.5 cmH 2 O L −1 s −1 ; p < .05), decreased inspiratory R L (12.6 ± 14.1 vs. 7.5 ± 4.5 cmH 2 O L −1 s −1 ; p < .05), and allowed RRI to return to baseline (p < .05). RRI dips index was an independent predictor of sleep-disordered breathing (SDB) when non-apneic REs were accounted for in symptomatic patients (p < .05). Conclusions: Non-apneic REs without cortical arousal or desaturation are associated with significant respiratory and heart rate changes. Optimal CPAP and the reduction of resistive load are associated with the normalization of heart rate indicating potential clinical benefit.
Sleep Medicine, 2006
Background and purpose: Excessive daytime sleepiness (EDS) is a major consequence of sleep-disordered breathing (SDB) in adults. In snoring children, spontaneous and respiratory arousals display reciprocal interactions, allowing for development of a new quantitative measure, the sleep pressure score (SPS), which provides intra-polysomnographic estimates of sleep pressure/disruption. The aim of the present study was to assess the interactions between respiratory and spontaneous arousals in adults with suspected SDB, and to examine whether the SPS and the Epworth sleepiness scale (ESS) are correlated. Patients and methods: Retrospective chart review of 530 adult patients who underwent polysomnographic evaluation for suspected SDB in two medical centers was performed. Polysomnographic studies reports, patients' demographics and ESS scores were reviewed. Results: Spontaneous and respiratory arousal indices and the apnea-hypopnea index (AHI) displayed negative and positive correlations respectively (rZK0.25, rZ0.97, P!0.0001) indicating reciprocal interactions between respiratory and spontaneous arousals during sleep. The AHI corresponding to the SPS at which the respiratory arousal/total arousal fraction exceeded the spontaneous arousal/total arousal fraction occurred at approximately 14/h of total sleep time (TST) (compared to 7/h TST in children) (P!0.001). No correlation was found between SPS values and ESS scores. Conclusions: As in children, snoring adults exhibit reciprocal interactions between respiratory and spontaneous arousals that can also be expressed as a single quantitative measure, the SPS, which is highly dependent on the severity of SDB and could possibly serve as a more reliable index of sleep disruption, considering that the ESS is unrelated to either SPS or AHI. q
Sleep, 1992
Some patients with excessive daytime sleepiness who do not present the features of obstructive sleep apnea syndrome (OSAS) present a sleep fragmentation due to transient alpha EEG arousals lasting between three and 14 seconds. These transient EEG arousals are related to an abnormal amount of breathing effort, indicated by peak inspiratory esophageal pressure (Pes) nadir. In the studied population, these increased efforts were associated with snoring. Usage of nasal CPAP, titrated on Pes nadir values, for several weeks eliminated subjective daytime sleepiness and improved Multiple Sleep Latency Test scores from baseline evaluations. Patients suspected of CNS hypersomnia should be asked about continuous snoring, and their clinical evaluation should include a good review of maxillo-mandibular and upper airway anatomy.
Dimensions of sleepiness and their correlations with sleep-disordered breathing in mild sleep apnea
Jornal Brasileiro de Pneumologia, 2009
OBJECTIVE: There are many ways of assessing sleepiness, which has many dimensions. In patients presenting a borderline apnea-hypopnea index (AHI, expressed as events/hour of sleep), the mechanisms of excessive daytime sleepiness (EDS) remain only partially understood. In the initial stages of sleep-disordered breathing, the AHI might be related to as-yet-unexplored EDS dimensions. METHODS: We reviewed the polysomnography results of 331 patients (52% males). The mean age was 40 ± 13 years, and the mean AHI was 4 ± 2 (range, 0-9). We assessed ten potential dimensions of sleepiness based on polysomnography results and medical histories. RESULTS: The AHI in non-rapid eye movement (NREM) stage 1 sleep (AHI-N1), in NREM stage 2 sleep (AHI-N2), and in REM sleep (AHI-REM) were, respectively, 6 ± 7, 3 ± 3 and 10 ± 4. The AHI-N2 correlated significantly with the greatest number of EDS dimensions (5/10), including the Epworth sleepiness scale score (r = 0.216, p < 0.001). Factor analysis, u...
Sleep Apnea Impairs the Arousal Response to Airway Occlusion
CHEST Journal, 1996
We hypothesized that the increased arousal threshold to upper airway occlusion exhibited by patients with obstructive sleep apnea (OSA) is in part secondary to the disease process itself. To test this hypothesis, we studied the effects of withdrawal of three nights of nasal continuous positive airway pressure (CPAP) treatment on arousal in six male patients with severe OSA who were using nasal CPAP on a long-term basis. During the control week, patients slept with nasal CPAP at home and on the first of 2 nights in the sleep laboratory (night CI, CPAP; night C2, no CPAP). During the apnea week, patients slept without nasal CPAP for 2 nights at home and 2 nights in the sleep lab¬ oratory (API, AP2). The control and apnea weeks were consecutive and in random order. The mean (±SEM) apnea+hypopnea index was 76.9±7.1 on API vs 3.1 ±1.0 events per hour on CI (p<0.05). Thus, the laboratory night (and presumably the 2 nights at home) preceding AP2 had dramatic in¬ creases in apnea compared with the nights preceding C2. The apnea duration during nonrapid eye movement sleep on nights following apnea was greater (AP2: 28.7±1.5 vs C2: 25.5±1.7 s; p<0.05) and the arousal threshold as reflected by the maximum esophageal pressure deflection preceding arousal was higher (DPmax) (AP2: 55.1 ±5.7 vs C2: 45.3±6.4 cm H20; p<0.005). We conclude that prior sleep apnea increases the arousal threshold to upper airway occlusion on subsequent nights and prolongs the apneic events. (CHEST 1996; 109:1490-96)
Immediate consequences of respiratory events in sleep disordered breathing
Sleep Medicine, 2005
Background: In obstructive sleep apnea/hypopnea syndrome, immediate physiological consequences of events have a dual role: censoring artifacts and gauging physiological significance. Newer airflow monitors may have changed the relative importance of these functions. The purpose of this study was to determine the frequency and hierarchy of occurrence of oxygen desaturation, EEG arousal and heart rate changes as immediate consequences of respiratory events.