Sleep Apnea Episodes Research Articles

Cost-effectiveness of adenotonsillectomy in reducing obstructive sleep apnea, cerebrovascular ischemia, vaso-occlusive pain, and ACS episodes in pediatric sickle cell disease

In children with sickle cell disease (SCD), adenotonsillar hypertrophy or recurrent tonsillitis are frequently linked with an increased risk of obstructive sleep apnea, cerebrovascular ischemia, or frequent pain episodes and often require an adenoidectomy and/or tonsillectomy. Interventions designed to prevent these complications, control vaso-occlusive pain episodes, and avoid hospitalizations may reduce the significant personal and economic burden of SCD. This study compares episode recurrence and treatment costs for cerebrovascular ischemia, vaso-occlusive pain, acute chest syndrome (ACS), and obstructive sleep apnea in children who had an adenotonsillectomy (A/T surgery, N = 256; 11.7%) and a matched cohort of those who did not (N = 512; 23.3%) from a cohort of 2,194 children and adolescents with SCD from South Carolina's Medicaid system. A/T surgery was associated with a significantly reduced rate of visits over time for obstructive sleep apnea and cerebrovascular ischemia (e.g., stroke, transient ischemic attacks), but not with any change in the rate of visits for vaso-occlusive pain or ACS/pneumonia visits. The rate of mean acute (emergency and inpatient) service costs was significantly decreasing over time after an increase about the time the A/T surgery was performed. The cost-effectiveness of adenoidectomy and/or tonsillectomy for treating obstructive sleep apnea and preventing cerebrovascular ischemia without increasing vaso-occlusive pain episodes or long-term acute service costs in routine clinical practice settings was demonstrated. The matched control group of SCD patients without A/T surgery contained more patients with severe vaso-occlusive pain episodes, ACS visits, and higher mean total costs over time and appears to represent a different phenotype of children with SCD.

Automatic detection and quantification of sleep apnea using heart rate variability

Detection of sleep apnea using electrocardiographic (ECG) parameters is noninvasive and inexpensive. Our approach is based on the hypothesis that the patient's sleep-wake cycle during episodes of sleep apnea modulates heart rate (HR) oscillations. These HR oscillations appear as low-frequency fluctuations of instantaneous HR (IHR) and can be detected using HR variability analysis in the frequency domain. The purpose of this study was to evaluate the efficacy of our ECG-based algorithm for sleep apnea detection and quantification. The algorithm first detects normal QRS complexes and R-R intervals used to derive IHR and to estimate its spectral power in several frequency ranges. A quadratic classifier, trained on the learning set, uses 2 parameters to classify the 1-minute epoch in the middle of each 6-minute window as either apneic or normal. The windows are advanced by 1-minute steps, and the classification process is repeated. As a measure of quantification, the algorithm correctly classified 84.7% of all the 1-minute epochs in the evaluation database; and as a measure of the accuracy of apnea classification, the algorithm correctly classified all 30 test recordings in the evaluation database either as apneic or normal. Our sleep apnea detection algorithm based on analysis of a single-lead ECG provides accurate apnea detection and quantification. Because of its noninvasive and low-cost nature, this algorithm has the potential for numerous applications in sleep medicine.

Is ‘MILD’ sleep‐disordered breathing in women really mild?

Sleep-disordered breathing (SDB) consists of episodes of periodic obstructive or central sleep apnea and partial upper airway obstruction. The first two are well recognized and diagnosed, although still underdiagnosed. Traditionally, research in SDB has focused mainly on male patients with obstructive sleep apnea using apnea/hypopnea index (AHI) as a measure of severity. This has led to overrating of AHI as the only marker of SDB and underestimating of SDB in women. However, recently, partial upper airway obstruction has been acknowledged to be pathological and it may cause symptoms of SDB. There is a growing body of evidence that women suffer from SDB more than thought before and they especially have partial upper airway obstruction. Co-morbidities such as cardiovascular diseases seem to be more prevalent in patients with SDB. This commentary points out some differences of SDB between genders in terms of symptoms and findings and emphasizes the clinical relevance of partial upper airway obstruction, especially in women.

Correlations between the duration and frequency of sleep apnea episode and hypoxemia in patients with obstructive sleep apnea syndrome

To evaluate the relationship between the duration of apnea episodes and the severity of hypoxemia of obstructive sleep apnea-hypopnea syndrome (OSAHS) patients and explore the possible causes of the disassociation between the severity of hypoxemia and AHI in some OSAHS subjects. Polysomnography data of eighty-two OSAHS patients was analyzed. Firstly, apnea and hypopnea events were classified into 4 groups respectively according to it's lengths, i.e., longer or equals to 10 s, 15 s, 20 s, 25 s, AHI10, AHI15, AHI20, AHI25 were obtained by calculating apnea hypopnea events per hour with respective lengths. Secondly, total apnea time per hour was calculated in all cases. Thirdly Spearman correlation coefficient and Linear regression analysis were used to measure the associations between numerical parameters referred above and three parameters of hypoxia: the lowest oxygen saturation level (LSaO2), the mean oxygen saturation level during sleep time (MeanSaO2), the percent of the total recorded time spent below 0.90 oxygen saturation level (TS90). The apnea-hypopnea index (AHI10, AHI15, AHI20, AHI25) correlated negatively with the LSaO2 (r was -0.636, -0.634, -0.649, -0.657), P < 0.01. The apnea-hypopnea index (AHI10, AHI15, AHI20, AHI25) correlated negatively with the MeanSaO2 (r was -0.659, -0.647, -0.648, -0.629), P < 0.01. The apnea-hypopnea index (AHI10, AHI15, AHI20, AHI25) correlated positively with the TS90 (r was 0.810, 0.806, 0.806, 0.770), P < 0.01. Further linear regression analysis all showed significant clinical value with r(2) > 0.50. The amount time of apnea events per hour of total sleep time (T) showed high correlations with LSaO2, MeanSaO2, TS90 (r was -0.650, -0.628, 0.776), while P < 0.01. The duration of apnea episodes has a significant clinical value in accessing the degree of hypoxia of the OSAHS patients. The TS90 combined with the LSaO2 reflects the severity of hypoxia of the OSAHS patients objectively.

Intermittent hypoxia: keeping it real

in this issue of the Journal of Applied Physiology , Tamisier and colleagues ([20][1]) describe a novel method for studying the effects of chronic intermittent hypoxia (CIH) in healthy human subjects. To investigate the effects of CIH on sleep, ventilatory control, and blood pressure, the authors

ICTAL APNEA OF EPILEPTIC ORIGIN

Epileptic seizures may be associated with changes of autonomic functions such as cardiac rhythm or breathing. Diagnostic problems may occur if only autonomic symptoms represent the epileptic seizure manifestation. Autonomic seizures such as ictal tachycardia have a high localizing value for seizure onset in the temporal region.1 In this report, we present two patients in whom the epileptic origin of central apnea could be established with ictal polygraphic EEG video recordings. ### Case 1. A 53-year-old woman with a history of right partial middle cerebral artery ischemia and early onset left face clonic seizures was admitted to our stroke unit because of transient mild left hemiparesis. MRI revealed an old right paracentral partial infarct of the middle cerebral artery. She was free of the clonic seizures for several months without antiepileptic medication. Polysomnography (PSG) (with nasal thermistor and belts for chest and abdominal movements), which was performed because of sleep apnea episodes, documented 18 central apneas consisting of cessation of airflow and breathing effort with oxygen desaturation of up to 70% associated with right hemisphere EEG seizure pattern (figure). All seizures occurred during sleep and caused awakening. Heart rate during the seizures stayed within the range of night sleep outside the seizures. Oxcarbazepine caused seizure freedom during 3 years follow-up. Figure All-night hypnogram (A) and ictal EEG (B) of patient 1 (A) The upper part …

Carvedilol Reduces the Severity of Central Sleep Apnea in Chronic Heart Failure

Background Carvedilol may reduce the severity of central sleep apnea (CSA) in patients with chronic heart failure (CHF). Methods and Results This study prospectively examined the effect of carvedilol on the severity of CSA in patients with CHF. Polysomnographic findings, left ventricular (LV) function, and plasma brain natriuretic peptide (BNP) level were evaluated before and 6 months after induction of carvedilol in 16 patients with CHF (New York Heart Association functional class II or III and LV ejection fraction <50%) who had CSA (central apnea index [CAI] >5 with dominant central apneic events). All patients tolerated carvedilol. The 6-month treatment with carvedilol increased the LV ejection fraction (32+/-7.4% to 45+/-9.8%, P<0.001) and decreased the BNP level (159 [69-458] pg/ml to 38 [16-193] pg/ml, P=0.017). The polysomnographic findings showed that the treatment decreased the apnea-hypopnea index (34+/-13 to 14+/-13, P=0.003) and CAI (13+/-11 to 1.9+/-4.3, P<0.001), whereas it increased the obstructive apnea index (1.1+/-1.5 to 3.1+/-3.4, P=0.04). Conclusion This preliminary study shows that treatment with carvedilol reduces the severity of CSA in patients with CHF, but that episodes of obstructive sleep apnea sometimes increase after the treatment.

Sleep apnea and REM sleep behavior disorder in patients with Chiari malformations

Chiari malformations (CM) may result in the appearance of REM sleep behavior disorder (RBD) and sleep apnea syndrome (SAS) that can be considered markers of brain stem dysfunction. To evaluate the frequency of RBD and SAS in patients with CM type I and II. Were evaluated 103 patients with CM by means of full night polysomnography. Were scoring different sleep stages, frequency of abnormal movements (through video monitoring) and abnormal respiratory events. Of the 103 patients, 36 showed CM type I and 67 CM type II. Episodes of RBD were observed in 23 patients. Abnormal apnea-hypopnea index (AHI) was observed in 65 patients. The high rate of RBD suggests that this parassomnia and the increased frequency of central sleep apnea episodes, may be considered as a marker of progressive brain stem dysfunction.

Timing of Nocturnal Ventricular Ectopy in Heart Failure Patients With Sleep Apnea

Ventricular ectopy is frequent in heart failure (HF) patients with sleep apnea. A previous report indicated that in HF patients, ventricular premature beats (VPB) occurred more frequently during episodes of recurrent central sleep apnea (CSA) than during normal breathing, and their frequency was greater during hyperpnea than during apnea. We hypothesized that, because respiratory stimuli that might provoke ventricular ectopy are stronger during obstructive apneas than during central apneas, in contrast to CSA, VPBs would be more frequent during apnea than hyperpnea in HF patients with obstructive sleep apnea (OSA). HF patients in sinus rhythm who have OSA or CSA (apnea-hypopnea index, > or = 15 events per hour) and with > 30 VPBs per hour were matched for severity of cardiac dysfunction and sleep apnea. The frequency of VPBs was then assessed during stage 2 sleep during the apneic and the hyperpneic phases of recurrent obstructive or central apneas. VPBs occurred more frequently during the apneic phase than during the hyperpneic phase in patients with OSA. In contrast, VPBs occurred more frequently during the hyperpneic phase than the apneic phase in patients with CSA. There was no difference in the degree of apnea-related oxygen desaturation between central and obstructive apneas. In patients with HF, nocturnal ventricular ectopy oscillates in time with oscillations in ventilation, with VPBs occurring predominantly during apneas in patients with OSA, but during hyperpneas in patients with CSA. This difference in VPB timing between OSA and CSA may be attributable to the differences in timing of arrhythmic stresses in these patients.

Epiglottic cyst in an infant

Epiglottic cyst is a rare cause of stridor and respiratory distress in newborns and infants. A 2-year-old girl was referred to our department for the treatment of an epiglottic cyst causing inspiratory stridor. Flexible fiberoptic laryngoscopy and a computed tomography (CT) scan revealed a cystic lesion on the lingual surface of the epiglottis. Frequent episodes of sleep apnea accompanied by desaturation had been observed during her sleep. Endoscopic deroofing was performed under general anesthesia. After the operation, stridor and sleep apnea disappeared.

Hypertension Finds Its Way into Psychiatric Practice

Hypertension Finds Its Way into Psychiatric Practice

Mésusage des médicaments du sommeil et de la vigilance: De l’effet indésirable à l’addiction

Sleep disorders, mainly insomnia and daytime somnolence, can arise from very different causes. For example insomnia may be related to anxiety-depression or occur in response to a stressful lifestyle or as an element of restless leg syndrome. Subjects with hypersomnia may present episodes of sleep apnea, drug-related depression or narcolepsia. Specific management is required for each etiology. Misuse of sleep drugs generally results from an insufficient etiological diagnosis and a misunderstanding of their proper use. These drugs can be used as necessary expedients but cannot replace correct management or treatment of the cause or causes of the sleep disorder. We present here a review of the undesirable effects, particularly among the elderly population, and of the risk of addiction to the different drugs used to induce sleep in order to propose prescription guidelines.

Relationship between cardiac arrhythmias and sleep apnoea in permanently paced patients with type I myotonic dystrophy

The long-term relationship between cardiac arrhythmias and sleep apnoea in myotonic dystrophy (DM1) is unknown. Pacemakers enabling the long-term monitoring of electrocardiographic and ventilation parameters were implanted in 20 patients with DM1 (mean age = 42 ± 11.6 years), followed 40 ± 12.3 months. Arrhythmias were recorded by the pacemaker in 17 patients (85%): 14 developed arrhythmic episodes that occurred either in absence or in presence of concomitant sleep apnoea. Conversely, among these 14 patients, the majority of sleep apnoea episodes were not associated with concomitant arrhythmias. In the other three patients who developed arrhythmias, simultaneous sleep apnoea was never observed. Episodes of sleep apnoea were observed in all patients, though only 85% presented with sleep apnoea syndrome. In conclusion, a high incidence of arrhythmias and sleep apnoea was observed. While arrhythmias are generally attributable to an organic substrate, they are sometimes precipitated by functional triggers, as in the case of sleep apnoea.

Valsalva maneuver, Müller maneuver: hemodynamic and reflex mechanisms, relevances

The time honored ancient reflex tests, the Valsalva and Müller maneuvers are still popular in the everyday clinical practice. These maneuvers are capable of imitating both trivial situations and significant pathological conditions. The Valsalva maneuver is still frequently used for the assessment of autonomic neuropathy. Addition of continuous noninvasive blood pressure monitoring allows assessment of both cardiac vagal and sympathetic driven peripheral vasomotor responses. The Müller maneuver has recently gained renewed popularity in simulating episodes of obstructive sleep apnea (OSA). Continuous monitoring of arterial pressure and muscle sympathetic nerve activity (MSNA) casts light on the close relationship between OSA and circulatory abnormalities.

American society of nephrology annual meeting San Diego, California, November 14–19, 2006

American society of nephrology annual meeting San Diego, California, November 14–19, 2006

Detection of Sleep Apnea Episodes from Multi-lead ECGs Considering Different Physiological Influences

This article deals with recognition of sleep apnea, using solely information available from multi-lead ECGs. Characteristic variations in heart rhythm and amplitude of the ECG are compared with respect to their diagnostic accuracy by means of an ROC analysis that is performed on a local similarity index. In 38 8-lead ECGs, each minute is classified with respect to occurrence of apnea events and the result is validated against expert annotations derived from synchronized polysomnographic recordings. Moreover, the results are compared to those obtained from the well known Physionet apnea-ECG database. Whereas the effect of amplitude modulation yields consistent results on both data sets (ROC-area 89.0% vs. 88.3%), a remarkable loss in performance is observed for the frequently applied heart rhythm (89.8% vs. 77.9%). Examples illustrating the reasons for this difference are given and discussed. With respect to aggregation of multi-lead information, two methods (PCA vs. averaging) are compared. The results indicate that averaging performs better (89.3%) than the adaptively estimated PCA (87.2) even when applied to a reduced set of leads. It is concluded that sleep apnea recognition from heart rhythm should always be complemented by analysis of the amplitude variations of the ECG.

Effects of Progesterone on Sleep: A Possible Pharmacological Treatment for Sleep-Breathing Disorders?

Progesterone is present in a wide spectrum of biological activity within a variety of tissues. This hormone is also known to affect reproduction, sleep quality, respiration, mood, appetite, learning, memory and sexual activity. Progesterone exerts a sleep induction or hypnotic effect and is a potent respiratory stimulant that has been associated to a decrease in the number of central and obstructive sleep apnea episodes in men. The literature also contains a substantial amount of data on the effect of apnea in women with obesity-hypoventilation during menopause. This review attempts to outline the specific role of progesterone in normal sleep and breathing as well as its possible therapeutic effects in the treatment of sleep-disordered breathing.

Evaluation of episodes of sleep apnea in patients with liver cirrhosis

Obstructive sleep apnea syndrome (OSAS) has been reported to be a new complication of liver cirrhosis with ascites. This fact prompted a study of episodes of sleep apnea as a function of the severity of cirrhosis. Forty eight patients with type C liver cirrhosis were divided according to the Child-Pugh score into 3 groups: Group A (16 patients with grade A cirrhosis), Group B (16 patients with grade B cirrhosis), and Group C (16 patients with grade C cirrhosis). Portable sleep polygraphs (Fuji RC, Inc. Tokyo, Japan) were attached to the subjects, and oronasal respiration, tracheal sounds, respiratory movements of the chest, and percutaneous arterial oxygen saturation continuously were recorded. A decrease in the mean airflow to 50% or less was defined as hypopnea, and the number per hour of episodes of apnea and hypopnea per hour lasting 10 seconds or longer (AHI) was counted. A Holter ECG was also recorded, and spectral heart rate variability during sleep was analyzed by measuring low frequency power (0.04-0.15 Hz, LF power), high frequency power (0.15-0.40 Hz, HF power), the ratio of LF power to HF power (LF/HF ratio), and very low frequency power (0.008-0.04 Hz, VLF power). The difference in QT interval between the lead CM5 and the lead CM1 (QTc dispersion) was also examined. AHI was significantly higher in Group C than in Groups A and B (p<0.05). In Group C, 6 patients with 20 times or more AHI per hour, obstructive sleep apnea, in which respiratory chest movements occur but oronasal respiration decreases or disappears, was observed. Spectral analyses of heart rate variability showed a decrease in HF power without sleep apnea, but increases in HF power and VLF power were observed during sleep apnea. The QTc dispersion increased during episodes of sleep apnea. As the stage of liver cirrhosis advanced, sleep apnea appeared, and changes in autonomic nervous activities were observed. Furthermore, QTc dispersion was increased during episodes of sleep apnea, presumably increasing the risk of ventricular arrhythmia.

A New Technique for Detecting Sleep Apnea-Related "Midnight" Surge of Blood Pressure

Patients with obstructive sleep apnea syndrome (OSAS) have been reported to be at greater risk for cardiovascular events, and midnight surge of blood pressure (BP) may be a mechanism of sleep apnea-related cardiovascular risk. However, there has been no accurate noninvasive technique to detect intermittent BP surge at the time of each sleep apnea episode. We therefore developed an experimental system to detect apnea-related short-term BP surge based on BP measurement triggered by peripheral (finger-tip) oxygen desaturation (a desaturation-triggered BP monitoring system). In 16 patients with OSAS, this new system successfully detected BP surges at the time of the sleep apnea, and the BP values were found to be significantly higher than those detected using a conventional fixed interval BP monitoring system (systolic BP [SBP] difference: 13 +/- 5.8 mmHg, p = 0.039; diastolic BP [DBP] difference: 10 +/- 6.8 mmHg, p = 0.032). The maximum SBP time rate (velocity of BP surge) showed a strong positive correlation with the apnea-hypopnea index (r = 0.855, p < 0.0001). In conclusion, we developed a noninvasive oxygen desaturation-triggered BP monitoring system that can successfully detect sleep apnea-related BP surge. The midnight BP surge detected by this new method was significantly associated with the severity of OSAS.

Physiologic Pacing in Patients With Obstructive Sleep Apnea: A Prospective, Randomized Crossover Trial

This study was designed to assess the impact of prevention of bradycardia with physiologic pacing on the severity of obstructive sleep apnea. Apneic episodes during sleep are associated with slowing of the heart rate during apnea and tachycardia with subsequent arousal. Patients with permanent pacemakers may have reduced episodes of sleep apnea when their pacemaker rate is set faster than their spontaneous nocturnal heart rate. We conducted a prospective, randomized, single-blind crossover trial of temporary atrial pacing in obstructive sleep apnea to reduce the apnea hypopnea index (AHI). Fifteen patients (age 60 +/- 13 years, 12 men) with moderate to severe obstructive sleep apnea (AHI 34 +/- 14) underwent insertion of an externalized atrial permanent pacing system via the left subclavian vein. Patients underwent overnight respiratory sleep studies in hospital, during atrial pacing at 75 beats/min, and with pacing turned off. The order of pacing mode was randomized, with crossover the subsequent night to the other mode. Patients were blinded to pacing mode, and the analysis of sleep recordings was blind to pacing mode. Pacing was tolerated without complications in all patients. Overnight physiologic pacing did not affect the AHI (pacing 39 +/- 21/h vs. control 42 +/- 21/h, p = 0.23, 95% confidence interval -9.3 to 2.5 for difference), desaturation time (pacing 3.8 +/- 6.0% vs. control 3.5 +/- 4.3%, p = 0.70), or the minimum SaO(2) (pacing 75 +/- 10% vs. control 77 +/- 11%, p = 0.38). There was a borderline significant reduction in circulatory time with pacing (pacing 23.4 +/- 3.2 s vs. control 25.5 +/- 4.4 s, p = 0.09). Temporary atrial pacing does not appear to improve respiratory manifestations of obstructive sleep apnea. Permanent atrial pacing in this patient population does not appear to be justified.