Non-invasive ventilation and sleep

In this paper, we review the effects of nocturnal mechanical ventilation on sleep. Indeed, although non-invasive assisted ventilation during sleep has been applied extensively, the exact effects of this treatment on sleep quality have not been thoroughly studied. In patients with severe chronic obstructive pulmonary disease and severe restrictive ventilatory defects, the resulting respiratory failure is aggravated by the specific effects of sleep on respiration. Non-invasive mechanical ventilation can lead to improvements in both ventilation and sleep quality. However, this is not always the case. Moreover, sleep-related leaks may jeopardize the efficiency of the ventilatory assistance which in turn may result in a deterioration in sleep quality. Non-invasive mechanical ventilation, if applied during sleep, should require a monitoring procedure during sleep with the aim of obtaining the best possible effects both on ventilation and on sleep quality.     

Recording of electroencephalograms and electrocardiograms during daytime sleep in trained canines: Preparation of the sleeping dogs

Abstract  Although respiration in trained canines is well investigated, the process of preparing dogs has not been described in any great detail. Moreover, their daytime patterns of sleep and wakefulness during 1 or 2 h of electroencephalogram (EEG) and electrocardiogram (ECG) recordings are not clear. Therefore, we describe the process of selecting and training dogs, in which we recorded EEG and ECG in the laboratory. First, 14 of 1242 dogs dealt with over a 1 year period were chosen. They were trained for 2 h to lie quietly and to sleep in the laboratory; this training procedure was repeated 152 times. Three dogs were then selected and a permanent tracheostomy was performed in one. Finally, EEG and ECG were recorded with the bipolar fine needle electrodes; respiration was recorded simultaneously through a tube inserted to a tracheostomy in one dog. Wakefulness, slow wave sleep (SWS) and rapid eye movement (REM) sleep (REMS) were identified according to the EEG pattern and on the basis of the behavioral criteria. Recordings were performed 12 or 13 times in each dog. Complete sleep cycles, including wakefulness, SWS and REMS in this sequence, were observed 3.9–4.1 times. The mean duration of SWS was 2.2–4.4 min and that of REMS was 3.5–4.6 min. The REMS latency was 33.9–41.8 min. Fluctuation of heart rate with respiration, termed respiratory sinus arrhythmia, was noted in the ECG. Heart beat increased with inspiration and decreased with expiration. The present study demonstrates how to select and train sleeping dogs and shows their undisturbed daytime sleep and wakefulness patterns.     

Assisted ventilation of newborn infants during sleep. Study of factors modifying adaptation to ventilation

During sleep, of ventilated newborns and young infants, spontaneous respiratory movements may occur, unrelated to the ventilation impulsions. The respiratory pattern is then classified as "active". On the contrary, the respiratory pattern is classified as "passive", when all respiratory movements are related to the ventilation insufflation. The factors which influence the dependence on the ventilator are studied in a group of 20 newborn and young infants. Prematurity, some biological data such as hyperoxia, hypocapnia, seem to favor this dependence. A rapid rate of ventilation (superior to 30/minute) is rarely related to an active respiration; a slow rate of ventilation seems favor this respiratory pattern. It is clear that adaptation to artificial ventilation is better during quiet sleep than during active sleep. Some physiopathological considerations are developed.     

Efficiency of invasive mechanical ventilation during sleep in Duchenne muscular dystrophy

ObjectiveInspiratory unintentional leaks (IULs) during noninvasive ventilation (NIV) adversely affect the sleep and the effectiveness of mechanical ventilation (MV). The aim of this study was to assess the effects of nocturnal IULs in Duchenne muscular dystrophy (DMD) patients with a tracheostomy and uncuffed tube comparatively with NIV patients.MethodsPolysomnography with transcutaneous partial pressure of carbon dioxide (PtcCO₂) recording and blood gas measurement was performed in 26 stable tracheostomized DMD patients using home MV, among whom 11 were matched with NIV patients.ResultsIULs occurred during 29.4% [1.7–61.9%] (median [IQR]) of the total sleep time. By univariate regression analysis, the closest correlation with IUL duration was for daytime base excess (r² = 0.69, P < 0.0001), followed by daytime bicarbonate level. In a stepwise multiple regression analysis, only base excess remained significantly correlated. Sleep and respiratory parameters improved in the four patients who agreed to use cuffed tubes. Tracheostomized patients had lower maximal PtcCO₂ (P = 0.02) and base excess values (P = 0.045) compared to NIV controls.ConclusionTracheostomy does not guarantee that MV is effective during sleep, as IULs may occur, but ensures better nocturnal gas exchanges than NIV. DMD patients should be evaluated using at least blood gas measurement, nocturnal oximetry, and PtcCO₂ monitoring.     

Non-invasive positive pressure ventilation for laryngeal contraction disorder during sleep in multiple system atrophy

We examined the usefulness of non-invasive positive pressure ventilation (NPPV) in the management of nocturnal laryngeal stridor associated with vocal cord dysfunction in five cases of multiple system atrophy (MSA). First, the patients were investigated during sleep induced by a minimal dose of propofol. Laryngoscopy showed paradoxical vocal cord movement resulting in inspiratory stridor. Electromyographic (EMG) study revealed synchronized bursts in the thyroarytenoid muscles and diaphragm in every inspiratory phase whenever the stridor emerged. NPPV was initiated after paradoxical movement was recognized with laryngoscopy. The NPPV mask was equipped with an additional channel for laryngoscopic monitoring. The optimal pressure for treatment was determined according to laryngoscopic and EMG findings. Next, NPPV was applied to natural sleep using the conditions determined in propofol-induced sleep. In all cases, NPPV eliminated nocturnal stridor and oxygen desaturation during natural sleep. Laryngoscopic observation during induced sleep is recommended as a useful procedure to titrate the optimal pressure for NPPV therapy. Since central hypoventilation progresses in the course of MSA, the choice of NPPV rather than continuous positive airway pressure should be encouraged to treat laryngeal contraction disorder associated with MSA.     

Effectiveness studies: advantages and disadvantages

In recent years, so-called "effectiveness studies," also called "real-world studies" or "pragmatic trials," have gained increasing importance in the context of evidence-based medicine. These studies follow less restrictive methodological standards than phase III studies in terms of patient selection, comedication, and other design issues, and their results should therefore be better generalizable than those of phase III trials. Effectiveness studies, like other types of phase IV studies, can therefore contribute to knowledge about medications and supply relevant information in addition to that gained from phase III trials. However, the less restrictive design and inherent methodological problems of phase IV studies have to be carefully considered. For example, the greater variance caused by the different kinds of confounders as well as problematic design issues, such as insensitive primary outcome criteria, unblinded treatment conditions, inclusion of chronic refractory patients, etc, can lead to wrong conclusions. Due to these methodological problems, effectiveness studies are on a principally lower level of evidence, adding only a complementary view to the results of phase III trials without falsifying their results.     

Gastrointestinal functioning during sleep: a new horizon in sleep medicine

A body of clinical and research literature is accumulating suggesting that there are significant alterations in gastrointestinal functioning during sleep, as well as sleep complaints and disorders in patients suffering from gastrointestinal disease. This review addresses the clinical applications of some basic alterations in gastrointestinal functioning during sleep, with a particular focus on gastroesophageal reflux disease and functional bowel disorders. Recent studies have shown that gastroesophageal reflux during sleep results in a marked prolongation of esophageal acid clearance time, and consequent mucosal damage. Data are reviewed which suggest that the more serious complications of gastroesophageal reflux, e.g. esophagitis and the extra-esophageal complications of reflux such as the exacerbation of bronchial asthma, laryngopharyngitis, and pulmonary aspiration are the result of sleep-related gastroesophageal reflux. Recent studies have also shown that patients with functional bowel disorder (e.g. irritable bowel syndrome and dyspepsia) have a high incidence of sleep complaints as well as abnormalities of autonomic functioning. Recent studies have shown that the measurement of autonomic functioning during sleep can differentiate the patients with functional bowel disorders from normal controls. The continued study of gastrointestinal functioning during sleep clearly establishes a new horizon of investigation in both sleep medicine and gastroenterology. 2001 Harcourt Publishers Ltd     

Fasciculations during wakefulness and sleep

Fasciculation potentials were quantitated during wakefulness (W) and the different sleep stages in 10 patients affected by motor neuron disease. Compared to W, no statistically significant variation was present in fasciculations during any sleep stage. Fasciculations remain unaffected by the decrease in central nervous system excitability which occurs during sleep.     

Sexsomnia: abnormal sexual behavior during sleep

This review attempts to assemble the characteristics of a distinct variant of sleepwalking called sexsomnia/sleepsex from the seemingly scarce literature into a coherent theoretical framework. Common features of sexsomnia include sexual arousal with autonomic activation (e.g. nocturnal erection, vaginal lubrication, nocturnal emission, dream orgasms). Somnambulistic sexual behavior and its clinical implications, the role of precipitating factors, diagnostic, treatment, and medico-legal issues are also reviewed. The characteristics of several individuals described in literature including their family/personal history of parasomnia as well as the abnormal behaviors occurring during sleep are reported.     

Newer antiepileptic drugs: advantages and disadvantages

The choice of an antiepileptic drug depends firstly on its efficacy in specific seizure types and epilepsies. However, it is imperative to consider whether possible adverse events will outweigh any benefits. The advantages and disadvantages of vigabatrin, lamotrigine, gabapentin, topiramate, tiagabine and felbamate are considered in some detail, and oxcarbazepine, stiripentol, remacemide, zonisamide and levetiracetam more briefly. Vigabatrin is effective for partial seizures and infantile spasms, but visual field defects are limiting its use. Lamotrigine has a wide spectrum, needs to be prescribed with care. Gabapentin is unlikely to cause adverse effects, but has relatively poor efficacy. Topiramate is widely effective, but can be poorly tolerated. Tiagabine is relatively untried in childhood epilepsies. The use of felbamate is restricted to severe refractory epilepsies. Stiripentol can be effective in severe myoclonic epilepsy in infancy. Zonisamide has a special place in the progressive myoclonus epilepsies. Levetiracetam, remacemide and oxcarbazepine have been used mainly for partial seizures: further studies of their roles in other circumstances are required.     

Stroke during sleep: epidemiological and clinical features.

Stroke during sleep is an unexplored area of vascular neurology and its pathogenesis; clinical significance and prevention still remain uncertain. The aim of our study was to determine the epidemiological and clinical patterns of ischemic stroke occurring during sleep. Consecutive patients (n = 1822) with acute ischemic stroke recorded in the Tel Aviv Stroke Register were studied. Stroke during sleep was determined whenever focal neurological deficit was verified to have occurred while the patient had been asleep. The comparisons between patients with stroke during sleep and while awake were performed using the t test with Bonferroni correction and the chi(2) test for age, sex, vascular risk factors (i.e. ischemic heart disease, myocardial infarction, atrial fibrillation, arterial hypertension, hyperlipidemia, diabetes mellitus, peripheral vascular disease, smoking), vascular distribution (carotid versus vertebrobasilar) and severity of stroke (mild, moderate or severe). Data regarding the onset of stroke (during sleep or while awake) were available for 1,671 patients. A minority of strokes occurred during sleep (n = 311, 18.6%), and stroke during sleep was severer (chi(2) = 11.9, p < 0.002). No significant differences were found in terms of age, sex and vascular distribution between the two groups. None of the vascular risk factors was found to be more frequent in stroke during sleep. Strokes occurring during sleep were found to be severer than those with onset while awake. However, no specific clinical patterns of risk factor profiles could be identified in these patients. Hemodynamic factors may play an important role in the occurrence of stroke during sleep, and this issue should be further investigated.     

The internet and children: advantages and disadvantages

This article examines how the Internet has entered children's lives and notes some of its potential positive and negative influences on children. Although the Internet's effects on a given child vary based on each child's characteristics and how the child uses the Internet, adults still must have a fundamental understanding of these general potentials. An awareness of the hazards inherent to children's Internet use is essential for all who work with children so they can apply preventive measures and help keep children safe. Whether a child uses the Internet and how a child uses the Internet significantly impact the Internet's influence on him or her. A child's personality and developmental needs also inevitably modify the Internet's influence on him or her.     

Obstructive sleep apnea and heart rate asymmetry microstructure during sleep

Purpose

Heart rate decelerations and accelerations have unequal input to heart rate variability (HRV) and patterns created by consecutive cardiac cycles—this phenomenon is known as heart rate asymmetry (HRA). The analysis of monotonic runs of heart rate decelerations and accelerations provides a detailed insight into the HRA microstructure and thus of HRV.

Aim

To evaluate the relation between the severity of obstructive sleep apnea (OSA) and the HRA microstructure during sleep.

Methods

Seventy-eight patients with suspected OSA underwent overnight polysomnography. The 300-min ECGs from the polysomnography were selected and analyzed. The HRA microstructure was quantified by measuring (1) the contribution of monotonic runs of decelerations or accelerations of different lengths to the number of all sinus beats, and (2) the length of the longest deceleration and acceleration runs.

Results

There were 19 patients with no/mild OSA (Apnea/Hypopnea Index (AHI) 5.1 ± 2.5/h), 18 with moderate OSA (AHI 21.8 ± 4.0/h) and 41 with severe OSA (AHI 42.8 ± 17.4/h). Patients with severe OSA had significantly reduced deceleration and acceleration runs of length 1 compared to the moderate OSA group, and compared to patients with no/mild OSA they had an increased number of longer runs (from 5 to 10 for accelerations and from 5 to 8 for decelerations; p < 0.05 for all comparisons). The longest acceleration runs were significantly longer in severe OSA group (p < 0.05) than in subjects with no/mild OSA.

Conclusions

HRA microstructure is related with OSA severity. An increased number of longer deceleration and acceleration runs is more common in severe OSA patients.     

Baroreflex modulation during sleep and in obstructive sleep apnea syndrome

This review focuses on the complex integration between cardiovascular reflexes and central autonomic influences controlling physiological sleep-dependent changes in arterial blood pressure and heart rate. A brief introduction on the anatomic and functional organization of the arterial baroreflex and the methods available to assess its function in humans is followed by an analysis of the functional interaction between autonomic nervous system and sleep mechanisms at the highest levels of brain organization. An insight into these interactions is important to shed light on the physiopathology of the most frequent complications of obstructive sleep apnea syndrome, such as sustained arterial hypertension, and excessive daytime sleepiness.     

Treatment of sleep apnea in chronic heart failure patients with auto-servo ventilation improves sleep fragmentation: a randomized controlled trial

BackgroundImpaired sleep efficiency is independently associated with worse prognosis in patients with chronic heart failure (CHF). Therefore, a test was conducted on whether auto-servo ventilation (ASV, biphasic positive airway pressure [BiPAP]–ASV, Philips Respironics) reduces sleep fragmentation and improves sleep efficiency in CHF patients with central sleep apnea (CSA) or obstructive sleep apnea (OSA).MethodsIn this multicenter, randomized, parallel group trial, a study was conducted on 63 CHF patients (age 64 ± 10 years; left ventricular ejection fraction 29 ± 7%) with CSA or OSA (apnea–hypopnea Index, AHI 47 ± 18/h; 46% CSA) referred to sleep laboratories of the four participating centers. Participants were randomized to either ASV (n = 32) or optimal medical treatment alone (control, n = 31).ResultsPolysomnography (PSG) and actigraphy at home (home) with centralized blinded scoring were obtained at baseline and 12 weeks. ASV significantly reduced sleep fragmentation (total arousal index_PSG: −16.4 ± 20.6 vs. −0.6 ± 13.2/h, p = 0.001; sleep fragmentation index_home: −7.6 ± 15.6 versus 4.3 ± 13.9/h, p = 0.003, respectively) and significantly increased sleep efficiency assessed by actigraphy (SE_home) compared to controls (2.3 ± 10.1 vs. −2.1 ± 6.9%, p = 0.002). Effects of ASV on sleep fragmentation and efficiency were similar in patients suffering from OSA and CSA.ConclusionsAt home, ASV treatment modestly improves sleep fragmentation as well as sleep efficiency in CHF patients having either CSA or OSA.     

Violent behavior during sleep: Prevalence,comorbidity and consequences

BackgroundViolent behaviors during sleep (VBS) are consequences of several sleep disorders but have received little attention in epidemiologic studies. This study aims to determine the prevalence of VBS in the general population and their comorbidity, familial links, course and treatment.MethodsRandom stratified sample of 19,961 participants, 15 years and older, from the general population of Finland, Germany, Italy, Portugal, Spain and the United Kingdom were interviewed by telephone using the Sleep-EVAL Expert System. They answered a questionnaire on VBS, their consequences and treatment. Parasomnias and sleep and mental disorders were also evaluated.ResultsVBS was reported by 1.6% (95% confidence interval: 1.4–1.7%) of the sample. VBS was higher in subjects younger than 35 years. During VBS episodes, 78.7% of VBS subjects reported vivid dreams and 31.4% hurt themselves or someone else. Only 12.3% of them consulted a physician for these behaviors. In 72.8% of cases, VBS were associated with other parasomnias (highest odds of VBS for sleepwalking and sleep terrors). Family history of VBS, sleepwalking and sleep terrors was reported more frequently in VBS than in non-VBS subjects with odds of 9.3, 2.0 and 4.2, respectively.ConclusionsVBS are frequent in the general population and often associated with dream-enactment, sleepwalking and sleep terrors. High frequency of VBS, sleepwalking and sleep terrors in family of VBS subjects indicated that some families have a greater vulnerability to sleep disorders involving motor dyscontrol. Subjects who consulted a physician for these behaviors mostly received inappropriate or no support, indicating a lack of knowledge about VBS.