The effects of sleep posture and sleep stage on apnea frequency

The Apnea Plus Hypopnea Index (A + HI) of 60 male positional sleep apneics was analyzed by sleep stage to determine if positional differences are limited to NREM sleep. Differences in apnea severity by sleep position were found to persist in REM sleep and to be of equal extent to those differences found in NREM sleep, despite the fact that there is also a significant increase in the frequency of apneic events associated with REM sleep. The positional effect persists in REM sleep, making treatments to control sleep posture a viable option.     

保留悬雍垂的腭咽成形加低温等离子射频治疗阻塞性睡眠呼吸暂停低通气综合征

目的 探讨保留悬雍垂的腭咽成形手术（URPPP）加低温等离子射频治疗阻塞性睡眠呼吸暂停低通气综合征（OSAHS）的疗效。方法 分别时46例和38例OSAHS患者行URPPP加低温等离子射频治疗和慈雍垂聘咽成形术，术后随访1年厦3年以上，比较两种手术方法的疗效。结果 术后1年UPPP组总有效率68．4％，URPPP加低温等离子射频手术组总有效率76．1％，差异无显著性。术后3年UPPP组总有效率45．8％，URPPP加低温等离子射频手术组总有效率73．3％，差异有显著性。结论 URPPP加低温等离子射频治疗OSAHS远期疗效较UPPP手术好，无严重并发症。     

改良腭咽成形术治疗阻塞性睡眠呼吸暂停综合征对白介素-6和内皮素-1的影响

目的观察改良腭咽成形术和悬雍垂腭咽成形术治疗阻塞性睡眠呼吸暂停综合征的疗效,及其对白介素-6（IL-6）和内皮素-1（ET-1）的影响。方法选取2007年1月至2013年12月在本院就诊的阻塞性睡眠呼吸暂停综合征（OSAHS）患者312例,按照手术方式不同分为传统治疗组和改良治疗组,每组各156例。传统治疗组予以传统的悬雍垂腭咽成形术,改良治疗组予以改良腭咽成形术。观察两组的手术疗效,及其对鼾声分级、嗜睡分级、IL-6和ET-1水平的影响。结果改良治疗组的总有效率为87.82%,传统治疗组的总有效率为76.28%,改良治疗组的疗效优于传统治疗组,差异有统计学意义（χ^2=6.290,P〈0.05）。治疗后两组的鼾声分级、嗜睡分级、IL-6和ET-1水平明显较治疗前降低（P〈0.01）,且改良治疗组的降低水平比传统治疗组更为明显,差异有统计学意义（P〈0.05或〈0.01）。结论改良腭咽成形术的疗效明显优于悬雍垂腭咽成形术,可能与保留悬雍垂和咽腔基本结构,降低了机体的炎症反应,保护了机体的内皮功能有关。     

The effects of hypoxia and sleep apnea on isoproterenol sensitivity

STUDY OBJECTIVES: To determine the effects of both apnea and hypoxia on beta-adrenergic receptor sensitivity. DESIGN: Cross-sectional study. SETTING: A clinical research center. PATIENTS: Forty-five normotensive and hypertensive sleep apnea patients (respiratory disturbance index >20) and non-apneic controls. MEASUREMENTS AND RESULTS: The chronotropic 25 dose (CD25), an in vivo measure of beta-adrenergic receptor sensitivity derived from the heart rate response to a graded infusion of isoproterenol, was determined while subjects breathed either a normoxic (21% O2, 79% N2) or a hypoxic (15% O2, 85% N2) gas mixture. Under normoxic conditions, apnea patients showed a significantly higher CD25 (lower beta-adrenergic receptor sensitivity) as compared to controls (5.9 microg, SD=2.1 versus 4.6 microg, SD=1.2, respectively; p=0.018). In response to hypoxia, apnea patients showed no change in CD25, while controls showed a significant increase in CD25 (beta-adrenergic receptor desensitization) (p=0.002), to a value comparable to the apneics' (5.6 microg, SD=2.0). CONCLUSION: The in vivo finding of reduced beta-adrenergic receptor sensitivity in sleep apnea patients is consistent with previous in vitro assessments of the beta-adrenergic receptor. The finding that apnea patients do not respond to hypoxia with a further receptor desensitization suggests that sleep apnea patients may have reached a threshold effect of hypoxia on the beta-adrenergic receptor. These findings may be relevant to the greater incidence of hypertension seen in patients with sleep apnea syndrome.     

Idiopathic central sleep apnea during REM sleep

Idiopathic central sleep apnea during rapid eye movement (REM) sleep is an extremely rare condition and only two cases have been reported so far. We present the case of a male patient who presented with chronic insomnia. Blood gas analysis during wakefulness suggested the presence of hypocapnia. Polysomnographic examination revealed central sleep apnea occurring predominantly during REM sleep. The patient responded well to continuous positive airway pressure (CPAP) at a pressure of 6 cmH₂O as well as to acetazolamide therapy.     

Combined bipolar radiofrequency surgery of the tongue base and uvulopalatopharyngoplasty for obstructive sleep apnea

Introduction

The aim of the study was to investigate the effectiveness of combined bipolar radiofrequency surgery of the tongue base (RFBT) and uvulopalatopharyngoplasty (UPPP) in a single session for obstructive sleep apnea and whether this combination is safe and well tolerated.

Material and methods

Seventy-nine patients with obstructive sleep apnea and both palatal and retroglossal obstruction underwent UPPP with bipolar RFBT. The control group consisted of 35 patients treated by UPPP alone.

Results

The apnea-hypopnea index significantly decreased from 28.7 to 14.1. The oxygen desaturation index decreased from 15.1 to 10.3. Mean oxygen saturation was unchanged. Subjectively, the Epworth Sleepiness Scale was significantly improved from 10.6 to 7.3, and the snoring level decreased from 8.4 to 6.0. The overall treatment success rate increased from 41.9% for UPPP alone to 51.7% for UPPP + RFBT. No serious adverse events occurred. Two patients had postoperative bleeding from the tonsillar bed after UPPP. Four patients had ulceration of the base of the tongue after RFBT with spontaneous cure. One patient had a taste change in half of the tongue that resolved within two months.

Conclusions

Combined bipolar RFBT and UPPP in a single session is well tolerated and safe surgery in the treatment of obstructive sleep apnea. It is effective in reducing respiratory parameters and subjective symptoms of obstructive sleep apnea. Further advantages are a single session, simple feasibility, bipolar technique and short time of the procedure.     

Swallowing and aspiration during sleep in patients with obstructive sleep apnea versus control individuals

Study ObjectivesThere are only a few reports on voluntary swallowing during sleep; therefore, this study aimed to propose a method for observing voluntary swallowing during sleep using polysomnography. The frequency of voluntary swallowing during sleep and the factors related to swallowing and aspiration during sleep were investigated.MethodsPolysomnography records of 20 control subjects and 60 patients with obstructive sleep apnea (OSA) (mild, moderate, and severe groups; n = 20 each) were collected. Simultaneous increases in the electromyographic potentials of the submental and masseter muscles, termed coactivation, and declining oronasal airflow (SA) were extracted as “swallowing.” The cough reflex that occurred during sleep was extracted as “aspiration.” The frequency of swallowing events was compared among the different OSA severity groups. Subsequently, a multivariate regression analysis was performed.ResultsThe average frequency of coactivation with SA in control subjects was 4.1 events/h and that without SA was 1.7 events/h. These frequencies increased with the severity of OSA during non-REM sleep. The distance of the hyoid to the Frankfurt plane was associated with the frequency of coactivation with (β = 0.298, p = 0.017) as well as without SA (β = 0.271, p = 0.038). The frequency of coactivation without SA was associated with aspiration (B = 0.192, p = 0.042).ConclusionsOur data provide new insights into the relationship between swallowing and aspiration during sleep. We found that the longer the distance from the hyoid bone to the Frankfurt plane, the higher the coactivation without SA, which could lead to aspiration during sleep.Clinical TrialsRetrospective observational study of swallowing during sleep in obstructive sleep apnea patients using polysomnography, https://upload.umin.ac.jp/cgi-open-bin/ctr/ctr_view.cgi?recptno=R000050460, UMIN000044187.     

Sleepiness-related accidents in sleep apnea patients

The frequency of motor vehicle and working accidents was analyzed by means of a strictly anonymous questionnaire in 156 patients with sleep apnea syndrome (SAS) and in 160 age-gender matched controls. In the SAS group 12.4% of all drivers had motor vehicle accidents as compared to 2.9% in the control group (p<0.005). The motor vehicle accident rate was 13.0 per million km in patients with more severe SAS (AHI > 34/h, n=78) as compared to 1.1 in patients with milder SAS (AHI 10-34/h, n=78) (p<0.05), and 0.78 in control group (p<0.005), respectively. The accident rates in both patients and the control group were also greater than the rate of 0.02 "accidents due to sleepiness" per one million km in the Swiss driving population as reported by official statistics. During treatment with nasal continuous airway pressure (nCPAP) in 85 SAS patients, the motor vehicle accident rate dropped from 10.6 to 2.7 per million km (p<0.05). We conclude that patients with moderate to severe SAS have an up to fifteen-fold risk increase of motor vehicle accidents that constitutes a serious and often underestimated hazard on the roads, which can be reduced by adequate treatment.     

Treatment effects on brain activity during a working memory task in obstructive sleep apnea

Positive airway pressure (PAP) is the most common form of treatment for obstructive sleep apnea (OSA). Treatment adherence is notoriously low, and holidays from treatment are common. To date, there is no literature on the effects of acute withdrawal from PAP treatment on the brain activity of individuals with OSA. Nine participants with OSA performed a 2‐Back verbal working memory paradigm during repeated functional magnetic resonance imaging (FMRI). Counterbalanced FMRI sessions were under conditions of PAP treatment (at least one consecutive week) or non‐treatment (for two consecutive nights). Treatment effects on 2‐Back‐related brain activity were significant, with greater deactivation in the right posterior insula and overactivation in the right inferior parietal lobule. The observed responses to PAP treatment withdrawal were more extreme in all regions of interest, such that 2‐Back‐related activity increased and 2‐Back‐related deactivation decreased further relative to the 0‐Back control task. The withdrawal of PAP treatment in effectively treated individuals with OSA might result in the need to reallocate resources in order to perform at the same cognitive level.     

Effects of pneumotachographic recording of breathing on sleep and respiration during sleep

Pneumotachographic recording of ventilation requires an air-tight nasobuccal face-mask which might disturb the subjects' sleep and modify their breathing patterns. In a cross-over randomized study, we compared recordings obtained with and without a face-mask in 20 healthy normal volunteers (10 males, 10 females, mean age: 21.7 +/- SEM 0.5 years). The sleep modifications that resulted from the presence of the face-mask were a lengthening of the REM-sleep latency (+ 38%, p less than 0.01), an increase in intrasleep waking-time (+ 55%, p less than 0.05), an increase in sleep stage-1 duration (+ 40%, p less than 0.02), and a decrease in REM-sleep duration (-20%, p less than 0.01), resulting in a decrease in total sleep duration (-9%, p less than 0.05). The sleep-latency, the number of awakenings, the sleep stage-2 duration, the deep slow wave sleep duration, the sleep stability and the number of sleep cycles were not significantly modified. The respiratory frequency was unchanged in any of the sleep stages. No obstructive or mixed apnoea was observed during the nights when the subjects wore the face-mask. The apnoea index for central apnoeas was low and remained unchanged with and without the face-mask (0.30 +/- 0.10 and 0.35 +/- 0.10 respectively). Thus the observed modifications do not rule out the basic advantage of the pneumotachographic method, that of being the only method to-date providing a direct quantitative measurement of respiratory flow and flow rate during sleep.     

The effect of acute exposure to morphine on breathing variability and cardiopulmonary coupling in men with obstructive sleep apnea: A randomized controlled trial

Opioid‐related deaths from respiratory depression are increasing but there is only limited information on the effect of morphine on breathing during sleep. This study aimed to detect and quantify opioid‐induced cardiorespiratory pattern changes during sleep in obstructive sleep apnea (OSA) patients using novel automated methods and correlate these with conventional polysomnography (PSG) measures. Under a randomized double‐blind placebo‐controlled crossover design, 60 male OSA patients attended two one‐night visits to the sleep laboratory, at least a week apart. Either a 40‐mg controlled‐release oral morphine dose or placebo was administered. Breathing during sleep was measured by standard in‐laboratory PSG. We analysed the inter‐breath interval (IBI) from the PSG flow channel to quantify breathing irregularity. Cardiopulmonary coupling (CPC) was analysed using the PSG electrocardiogram (ECG) channel. Following the consumption of morphine, the 60 OSA patients had fewer breaths (p = .0006), a longer inter‐breath interval (p < .0001) and more irregular breathing with increased IBI coefficient of variation (CV) (p = .0015) compared to the placebo night. A higher CPC sleep quality index was found with morphine use. The change of key IBI and CPC parameters was significantly correlated with the change of key PSG sleep‐disordered breathing parameters. In conclusion, 40 mg controlled‐release morphine resulted in a longer breathing cycle and increased breathing irregularity but generally more stable sleep in OSA patients. The significant links between the IBI and CPC techniques and a range of PSG sleep‐disordered breathing parameters may suggest a practical value as surrogate overnight cardiorespiratory measurements, because both respiratory flow and ECG can be detected by small portable devices.     

Neurochemical perspectives on the control of breathing during sleep

A specific depression of minute ventilation occurs during sleep in normal subjects. This sleep-related ventilatory depression is partially related to mechanical events and upper airway atonia but some data also indicate that it is likely to be centrally mediated. This paper reviews the anatomical and neurochemical connections between sleep/wake- and respiratory-related areas in an attempt to identify the potential implication of sleep-related neurochemicals (serotonin, catecholamines, GABA, acetylcholine) in the sleep-related hypoventilation. The review of available data suggests that the sleep-related ventilatory depression depends upon the enhanced GABAergic activity together with a loss of suprapontine influence depending on the cessation of activity of the reticular formation. During REM sleep, an additional inhibitory activity emerges from the pontine cholinergic neurons, which contributes to the breathing irregularities and the associated depression of minute ventilation and ventilatory response to chemical stimuli. This model may contribute to a better understanding of the neurochemical environment of respiratory neurons during sleep, which remains a question of importance regarding the numerous pathological states that are linked to specific perturbations of breathing control during sleep.     

Treatment of obstructive sleep apnea in achondroplasia: Evaluation of sleep,breathing, and somatosensory-evoked potentials

The occurrence of obstructive sleep apnea (OSA) in achondroplasia has been linked to brain stem compression. Overnight sleep studies (11 subjects) and somatosensoryevoked potentials (SEP's, 10 subjects) were recorded before and after conventional treatment of OSA in achondroplasia. The two groups were derived from 30 subjects who underwent diagnostic sleep studies and SEPs, including 15 females and 15 males with a median age 6.6 of years (range 1.0–47.6) at the time of the first study. In 30 initial studies there was no correlation between severity of OSA and abnormalities on SEP evaluation. Treatment of 17 subjects included adenotonsillectomy (n = 3), weight loss (n = 1), and nasal-mask continuous positive airway pressure (CPAP) (n = 13). Sleep studies in 11 subjects after a delay of 8.8 ± 2.8 months showed a reduction in respiratory disturbance index (RDI) from 38.4 ± 6.9 to 6.5 ± 1.8 events hr^?1 (p < 0.001) and movements/arousals fell from 10.4 ± 2.2 to 4.8 ± 0.2 hr^?1 (p < 0.04). Obstructive events were reduced from 33.7 ± 6.9 to 2.4 ± 1.0 hr^?1 (p < 0.001). Improvement of respiratory indices was associated with an increased proportion of slow-wave sleep from 25.2 ± 4.0% to 32.3 ± 2.4% (p = 0.01), and decrease in stage 1–2 sleep from 59.3 ± 5.8% to 46.6 ± 1.9% (p = 0.03). There was no increase in the percentage of REM sleep (15.2% to 21.2%). Repeat SEP studies in 10 subjects, after clinically effective treatment of OSA, showed improvement of SEP score of at least 1 grade, in 5 of 7 (71%) with initially abnormal values. We conclude that treatment to relieve upper airway obstruction improves OSA in achondroplasia, accompanied by changes in sleep structure and, in some cases, improved studies of neurological function. © 1995 Wiley-Liss, Inc.     

REM sleep episodes during the maintenance of wakefulness test in patients with sleep apnea syndrome and patients with narcolepsy

Twelve patients with sleep apnea, 12 narcoleptic patients, and 10 controls were given 20-min opportunities to remain awake while sitting comfortably. Test sessions were administered at 10:00, 12:00, 14:00, 16:00, and 18:00. Apneic and narcoleptic subjects were less capable of maintaining wakefulness than controls. Patients with sleep apnea had an average of 1.4 daytime rapid eye movement (REM) episodes with the peak incidence at 14:00. Narcoleptics also had sleep onset REM periods (mean of 2.7), whereas none of the controls had REM episodes during the daytime testing. Narcoleptic and control groups differed in the probability of REM occurring at each session. There were time-of-day differences in the probability of REM occurring between patient groups. The amount of stage REM the night preceding testing was unrelated to the occurrence of REM episodes during the day in either patient group. In addition, there were notable differences in the frequency of sleep onset REM periods when patients were sitting as opposed to being supine during nap studies. Sleep latency and frequency of REM episodes on the maintenance of wakefulness test were independent of the subject's age. The maintenance of wakefulness test proved unsatisfactory as a diagnostic procedure, but appeared useful as an adjunct procedure in the evaluation of treatment efficacy of hypersomnia.     

Oxygen desaturation during night sleep affects decision‐making in patients with obstructive sleep apnea

This study assessed decision‐making and its associations with executive functions and sleep‐related factors in patients with obstructive sleep apnea. Thirty patients with untreated obstructive sleep apnea and 20 healthy age‐ and education‐matched controls performed the Iowa Gambling Task, a decision‐making task under initial ambiguity, as well as an extensive neuropsychological test battery. Patients, but not controls, also underwent a detailed polysomnographic assessment. Results of group analyses showed that patients performed at the same level of controls on the Iowa Gambling Task. However, the proportion of risky performers was significantly higher in the patient group than in the control group. Decision‐making did not correlate with executive functions and subjective ratings of sleepiness, whereas there was a significant positive correlation between advantageous performance on the Iowa Gambling Task and percentage of N2 sleep, minimal oxygen saturation, average oxygen saturation and time spent below 90% oxygen saturation level. Also, the minimal oxygen saturation accounted for 27% of variance in decision‐making. In conclusion, this study shows that a subgroup of patients with obstructive sleep apnea may be at risk of disadvantageous decision‐making under ambiguity. Among the sleep‐related factors, oxygen saturation is a significant predictor of advantageous decision‐making.     

Behavior problems associated with sleep disordered breathing in school-aged children--the Tucson children's assessment of sleep apnea study

OBJECTIVE: The purpose of the current study was to examine prevalence of and relations between a commonly used measure of nighttime breathing problems, the Respiratory Disturbance Index (RDI), and a range of problem behaviors in community children. METHODS: Participants were 403 unreferred children aged 6-12 years. Recruitment was completed through public elementary schools. Overnight unattended in-home polysomnography was used to assess sleep and breathing. The RDI was used as the indicator of respiratory events during sleep. The Child Behavior Checklist and the Conners' Parent Rating Scales-Revised were used to assess behavior. RESULTS: Prevalence rates for Attention, Cognitive Problems, Aggression, Oppositional behavior, and Social Problems were greatest for subjects with high RDIs. Prevalence for Internalizing behaviors was not greater for those subjects with high RDIs. Hyperactivity was not strongly related to higher RDIs. CONCLUSIONS: Behavioral problems may exist in the presence of nocturnal breathing events in unreferred children. Specific patterns of behavioral morbidity have still not been established. Some behaviors, such as hyperactivity, may show differing sensitivity and specificity in relation to the RDI.