Mixed Sleep Apnea Research Articles

Severe Mixed Sleep Apnea After Bilateral Lung Transplantation in a Cystic Fibrosis Patient: A Case Report

Background Lung transplantation is the only treatment for end-stage lung disease in selected patients. After lung transplantation, patient recovery is often slow owing to severe underlying diseases in the patient producing hypoxemia before, during, and after surgery, as well as infections and rejection episodes. Postoperative breathing and ventillatory disorders are also associated with diaphragmatic dysfunction and/or phrenic nerve damage. Methods Herein we have reported a case of a 35-year-old man undergoing bilateral lung transplantation owing to worsening of chronic respiratory failure from cystic fibrosis. After uncomplicated surgery, weaning was delayed due to nighttime dyspnea and hypoxemia attributed to diaphragm dysfunction. After improvement of diaphragm function, the symptoms persisted, requiring noninvasive nocturnal ventilatory support. Polysomnography confirmed severe mixed sleep apnea. Results Effective treatment with noninvasive bi-level positive airway pressure spontaneous/timed mode (BiPAP S/T) ventilation during the nights rendered the patient symptom free. Polysomnography confirmed successful treatment. Conclusion Disordered breathing while sleeping is common after solid organ transplantation. BiPAP S/T ventilator therapy was effective to the treat dominantly central sleep apnea in our patient.

Energy based feature extraction for classification of sleep apnea syndrome

In this paper it is aimed to classify sleep apnea syndrome (SAS) by using discrete wavelet transforms (DWT) and an artificial neural network (ANN). The abdominal and thoracic respiration signals are separated into spectral components by using multi-resolution DWT. Then the energy of these spectral components are applied to the inputs of the ANN. The neural network was configured to give three outputs to classify the SAS situation of the subject. The apnea can be mainly classified into three types: obstructive sleep apnea (OSA), central sleep apnea (CSA) and mixed sleep apnea (MSA). During OSA, the airway is blocked while respiratory efforts continue. During CSA the airway is open, however, there are no respiratory efforts. In this paper we aim to classify sleep apnea in one of three basic types: obstructive, central and mixed. A significant result was obtained.

Classıfıcation of sleep apnea by using wavelet transform and artificial neural networks

This paper describes a new method to classify sleep apnea syndrome (SAS) by using wavelet transforms and an artificial neural network (ANN). The network was trained and tested for different momentum coefficients. The abdominal respiration signals are separated into spectral components by using multi-resolution wavelet transforms. These spectral components are applied to the inputs of the artificial neural network. Then the neural network was configured to give three outputs to classify the SAS situation of the patient. The apnea can be broadly classified into three types: obstructive sleep apnea (OSA), central sleep apnea (CSA) and mixed sleep apnea (MSA). During OSA, the airway is blocked while respiratory efforts continue. During CSA the airway is open, however, there are no respiratory efforts. In this paper we aim to classify sleep apnea in one of three basic types: obstructive, central and mixed.

Classification of Sleep Apnea through Sub-band Energy of Abdominal Effort Signal Using Wavelets + Neural Networks

Detection and classification of sleep apnea syndrome (SAS) is a critical problem. In this study an efficient method for classification sleep apnea through sub-band energy of abdominal effort using a particularly designed hybrid classifier as Wavelets + Neural Network is proposed. The Abdominal respiration signals were separated into spectral sub-band energy components with multi-resolution Discrete Wavelet Transform (DWT). The energy content of these spectral components was applied to the input of the artificial neural network (ANN). The ANN was configured to give three outputs dedicated to SAS cases; obstructive sleep apnea (OSA), central sleep apnea (CSA) and mixed sleep apnea (MSA). Through the network, satisfactory results that rewarding 85.62% mean accuracy in classifying SAS were obtained.

Success and failure of mirtazapine as alternative treatment in elderly stroke patients with sleep apnea—a preliminary open trial

More than two thirds of stroke patients suffer from sleep apnea. A recent study showed that mirtazapine reduced the respiratory disturbance index (RDI) of a stroke patient by 80%. These promising results prompted us to offer mirtazapine to non-depressed stroke patients who suffered from sleep apnea and refused treatment with a continuous positive airway pressure (CPAP) device. Polysomnography was performed between 2200 and 0600 hours. We examined ten inpatients [nine male, one female; mean age of 68.7 +/- 1.5 years +/- SE; body mass index of 26.1 +/- 1.2 kg/m(2), basal ganglia bleeding (n = 3), middle cerebral artery ischemia (n = 4), basal ganglia ischemia (n = 1), cerebellar bleeding (n = 2)] in the Neurologic Clinic's sleep laboratory. The mean duration of illness before the first polysomnography was 52.6 +/- 11.4 days. Mirtazapine effectively consolidated sleep in all patients, i.e., sleep efficiency significantly increased from 63.1 +/- 4.8% to 75.7 +/- 5.0%. A moderate increase in RDI (137.4 +/- 15.3% of baseline) occurred during initial mirtazapine administration (intake duration 15.8 +/- 5.5 days). After 51.9 +/- 8.4 days, the RDI was either reduced (51.9% in "responders" who were identified arbitrarily by a reduction in RDI >or= 25% at any time point of the investigation) or increased (154.4% in "non-responders"). Mirtazapine administration was stopped in the four patients with increased RDI. Mirtazapine may be a probably effective treatment in stroke survivors with obstructive sleep apnea who refuse nasal CPAP treatment. As it may worsen central and mixed sleep apnea, patients who receive mirtazapine to alleviate sleep apnea or to control post-stroke depression with sleep disturbances should be monitored for changes in breathing parameters during sleep.

Friedreich's ataxia: A clinical and genetic analysis

We report a patient with genetically confirmed Friedreich's ataxia (FRDA) who developed a previously unreported feature of a mixed sleep apnea. Initial mutation analysis, by PCR, of the parental frataxin alleles showed an apparent de novo mutation in the maternal germline. Further investigation using Southern blot analysis showed that the mother did carry an expanded mutant frataxin allele. Based upon published data, FRDA resulting from at least one allelic spontaneous expansion mutation is rare with a frequency of less than 1/1,000,000. The presence of such a mutation should be confirmed by Southern blot analysis. Our patient expands the neurological features of FRDA to include sleep apnea. The genetic analysis of the family demonstrates the importance of Southern blot analysis for accurate genotyping which, in turn, has implications for genetic counseling.

Neurological perspective on obstructive and nonobstructive sleep apnea.

One of every 15 adults in the United States has at least moderate sleep apnea. The true prevalence is higher, as approximately 0.3 to 5% of adults with sleep apnea are undiagnosed. Sleep apnea has major health consequences; therefore, neurologists must recognize and treat sleep apnea syndromes appropriately. There are three main categories of sleep apnea: obstructive sleep apnea (OSA), central sleep apnea (CSA), and mixed sleep apnea. OSA results from upper airway obstruction, and CSA is due to lack of inspiratory muscle effort; mixed apnea results from a combination of these factors. Sleep apnea syndromes can present within the spectrum of "typical" neurological complaints, including forgetfulness, headaches, sleepiness, fatigability, seizures, and muscle and nerve weakness. A good sleep history, a nocturnal polysomnogram, and multiple sleep latency test are important in elucidating the diagnosis and validating the complaints of sleepiness. The gold standard for treatment of OSA is positive airway pressure, although some patients may benefit from surgical interventions designed to bypass the site of airway obstruction. With CSA, treatment is directed toward the underlying disorder. Patients with CSA may also benefit from several types of nasal positive airway pressure treatment, while some require mechanical ventilation.

Continuous positive airway pressure therapy in sleep apnoea.

Sleep apnoea is associated with increased mortality and morbidity. The treatment goal is to reduce the neurocognitive and cardiovascular sequelae. CPAP therapy in sleep apnoea is discussed in two parts in the article. The first part will consider CPAP therapy in the more common form of sleep apnoea (i.e. obstructive or mixed sleep apnoea) and the second part will consider CPAP therapy in central sleep apnoea. Alternative positive airway pressure modalities are discussed. CPAP therapy has been extensively studied and it remains the mainstay of treatment in obstructive sleep apnoea, as it is still the most consistently efficacious and safe option. However, its major disadvantage is that it does not confer a cure to this disorder and hence therapy is generally life long with its usual treatment compliance problems. As such, there are continuous improvement strategies. The role of CPAP therapy in central sleep apnoea is more limited. There has been increasing data on the beneficial effect of CPAP on central sleep apnoea/Cheyne-Stokes respiration in congestive heart failure. Evidence for CPAP therapy in sleep apnoea has evolved significantly over the last decade. However, more research and publication of large-scale long-term randomized trials of treatment in sleep apnoea to assess patient-orientated outcomes and preferences are necessary.

Sleep disordered breathing in the elderly.

Sleep disordered breathing (SDB), i.e., obstructive, central or mixed sleep apneas, has been recognized as a common occurrence in the elderly. Aging is per se associated with a decrease in the quality of sleep; SDB may further disrupt the sleep architecture in older subjects. The prevalence of obstructive sleep apnea (OSA) increases with aging; available studies report prevalence rates of 11-62%. Furthermore, OSA has been associated with increased mortality in older adults. Central apneas and periodic breathing occur with increased frequency either in subjects with neurological disorders such as infarction, tumor, sequelae of infection, diffuse encephalopathies, or in chronic heart failure. Patients with cerebrovascular disease (stroke, or transient ischemic attacks) have a markedly high prevalence of SDB, mainly OSA. In these patients, SDB is associated with a poorer functional prognosis at 3 and 12 months after the acute event, and a higher mortality. The clinical impact of SDB on cognitive function appears to be modest in patients without dementia, although there is a moderate increase in daytime sleepiness. In Alzheimer's disease (AD) however, SDB occurs more frequently than in non-demented older subjects, and its severity is correlated with the degree of cognitive impairment. The hypothesis of a causal relationship between AD and SDB remains a subject of controversy. The possibility of SDB should be considered in the elderly in the differential diagnosis of "reversible dementias", increased daytime sleepiness, or unexplained right-sided heart failure.

Frequency of Obstructive and Mixed Sleep Apneas in 1,023 Infants

To collect normative data on the frequency of obstructive and mixed sleep apneas in healthy infants. 1100 infants were recorded during one night in a sleep laboratory. the recordings were performed in an infant sleep laboratory. The recordings of 1023 infants were used for analysis, the data of 77 infants being excluded because of poor recording quality. The infants were born full-term, were healthy at the time of study, had no history of apnea and were aged between 2 and 28 weeks. The polysomnographic recordings were analyzed visually and were subdivided according to the age of the subjects into 2-7 weeks, 8-11 weeks, 12-15 weeks, 16-19 weeks and 20-27 weeks of life. NA. At 2-7 weeks of life, obstructive apneas (p=.013) and mixed apneas (p=.004) were significantly more frequent than at any other age group. At 8 to 11 weeks of life, obstructive apneas were significantly more frequent in boys than girls (p=.016). The present findings add to our knowledge of infants' respiratory characteristics during sleep.

Respiratory disturbances during sleep in syringomyelia and syringobulbia.

To determine the frequency and types of abnormalities of respiratory control during sleep in syringomyelia and syringobulbia and to provide a basis to predict patients at risk of sudden death. Thirty patients (15 male and 15 female; mean age 39.0 +/- 12.6 years) with communicating syringomyelia were divided into two groups: those with evidence of syringobulbia (17 patients) and those without compromise of the medulla or syringomyelia (13 patients). Patients were studied with pulmonary function studies and polysomnography. Respiratory center sensitivity to CO2 (rebreathing technique) was measured in 9 patients. Severely affected patients had mild-to-moderate restriction and individual patients had bilateral diaphragmatic or vocal cord palsy, abnormal respiratory rhythm, prolonged inspiratory time, or an abnormal respiratory response to CO2. Very prolonged central, obstructive, and mixed sleep apneas with low O2 saturation values and a fixed heart rate were recorded in most patients with syringobulbia. Five patients developed severe respiratory complications and died during a follow-up period of 10 years. Respiratory abnormalities failed to correlate with syrinx size. Severe abnormalities in respiratory rhythm generation during sleep occur in patients with syringobulbia. The respiratory disturbances are not due to muscle weakness and they are not correlated with the size of the cavity. The combination of dysphagia and dysphonia in patients with longstanding syringomyelia and syringobulbia predicted likelihood of respiratory disturbances during sleep.

Comparative clinical and physiological features of Maori, Pacific Islanders and Europeans with sleep related breathing disorders

Recent studies have suggested that there is a familial association of sleep apnoea syndrome and that this is not entirely explained by inheritance of known risk factors. Maori (M) and Pacific Islanders (PI) have many of the body habitus features associated with sleep apnoea and therefore might be expected to exhibit more severe disease than Europeans (E). To compare the clinical and physiological characteristics of the different ethnic groups and to determine if race was an independent predictor of severity of sleep apnoea. A prospective evaluation of patients attending the Sleep Disordered Breathing Clinic which serves the whole of Auckland (population 1.1 million), New Zealand was conducted for the period July 1994 to August 1995. The evaluation included history including a 26 question questionnaire, Epworth sleepiness score, examination, and where indicated, full polysomnography. A total of 233 patients (154 E, 48 M and 33 PI), underwent full polysomnography. Forty-one (85%) of the M and 31 (94%) of PI had obstructive or mixed sleep apnoea compared with only 74 (49%) of the E (P < 0.0001; chi 2). There were few racial differences in the responses to the sleep questionnaire. M and PI were shown to have much greater neck and waist circumference and body mass indices. Severity parameters (apnoea-hypopnoea index, wake and minimum oxygen saturation, and apnoea duration) were greater for both M and PI compared with E (P < 0.001; Mann-Whitney U-test). Stepwise regression identified neck size, body mass index and age as independent predictors of severity. When other factors were controlled for, race was not an important independent predictor of severity of sleep apnoea.

Comparison of dental intraoral devices for snoring therapy: A subjective survey of their effect on mixed sleep apnea syndrome

Comparison of dental intraoral devices for snoring therapy: A subjective survey of their effect on mixed sleep apnea syndrome

First Experience with Cilazapril in the Treatment of Sleep Apnoea-Related Hypertension

Sleep-related breathing disorders are associated with considerably impaired vitality and reduced life expectancy. In this respect, a particularly important role is played by obstructive snoring and obstructive or mixed sleep apnoea. Because of the often underestimated prevalence of sleep-related breathing disorders and their association with hypertension in greater than 50% of patients, it is important to introduce antihypertensive drug therapy that does not exacerbate the effects and the degree of these disorders, and that above all produces an adequate lowering of blood pressure by night. In the present study in 12 patients, it has been shown that the new ACE inhibitor, cilazapril, achieves a good reduction in blood pressure over 24 hours and during all stages of sleep, without any negative influence on the ratio of REM: nonREM sleep. The apnoea index was reduced from 40 (range 12 to 84) to 27 (range 0 to 72) apnoeas per hour of sleep (p less than 0.01). It will be increasingly important to take into account the effects of antihypertensive therapy on other clinical parameters, especially the nocturnal blood pressure profile and its association with sleep-related breathing disorders.

Ambulatory monitoring in sleep apnoea presenting with nocturnal episodic phenomena

Episodic nocturnal phenomena represent a separate cluster of disturbances within the classification of sleep disorders. The reported case history covers paroxysmal signs occurring secondary to a REM-dependent mixed sleep apnoea syndrome. The pathophysiology of similar episodes in elderly (non-)epileptic patients is discussed. Ambulatory monitoring is an appropriate technique for investigation if respiratory and motor activity, and EEG and ECG are recorded simultaneously.

Pulmonary Artery Pressure during Sleep Apnea

Elevations of pulmonary arterial pressure (PPA) during sleep apnea have been attributed mainly to blood gas changes induced by the apnea. We evaluated the PPA changes associated with various degrees of hypoxia related to the central component of mixed apnea. A total of 105 patients with mixed apneas were monitored during non-REM sleep. PPA was measured by means of a Swan Ganz catheter; oxygen saturation (SaO2), by means of pulse oximetry. All apneas were associated with a variable drop in SaO2. PPA was always stable during the central component of the apnea and increased only during the obstructive segment. Table 1 presents the statistics. Statistical evaluation of SaO2 changes between beginning and end of central apnea component indicated a significant variation (p<.001). Conversely, there was no statistically significant change in PPA between beginning and end of the central apneic component, while a significant increase was noted when the PPA delta between beginning and end of the total mixed apnea was calculated (p<.001). Contrary to the widely accepted hypothesis of hypoxic vasoconstriction, we did not find any significant correlation between SaO2 drops and PPA increase in the central component of the mixed sleep apnea. Only a significant correlation between the duration of the obstructive segment and the PPA increase (p<.001) could be found. We believe that mechanical influences—equivalent to successive Müller maneuvers—are far more important in explaining the PPA increases in sleep apnea.

Polysomnographic Studies of Infants Who Subsequently Died of Sudden Infant Death Syndrome

The polygraphic findings from 11 future victims of sudden infant death syndrome (SIDS) are reported and compared with those of matched pairs of control infants. The recordings had been done to alleviate parental anxiety about sleep apnea. Four infants had siblings who were victims of SIDS. Two infants were studied 3.5 to 9.5 weeks before their deaths because of an unexplained apparent life-threatening event that had occurred during sleep. For each victim of SIDS, two control infants were selected from the 2,000 infants who had been tested in the same hospitals. They were matched for sex, gestational age, postnatal age, and weight at birth with the SIDS victims. Their polygraphic recordings had been performed within similar conditions. Each record was allocated a random code number and was analyzed without knowledge of the patient's identity by two independent scorers. Most sleep and cardiorespiratory variables studied did not differentiate SIDS victims from control infants. Only four variables significantly characterized the future SIDS victims: the maximal duration of central apneas, the number of sighs followed by a central apnea, the presence of obstructive apneas, and the presence of mixed apneas. Central apneas were longer during all sleep states in the SIDS victims compared with their matched controls, but none exceeded 14 seconds. Sighs immediately followed by an apnea were significantly less frequent in the future SIDS group. Obstructive and mixed sleep apneas were seen in eight of 11 SIDS victims and in only three of 22 control infants.(ABSTRACT TRUNCATED AT 250 WORDS)

Preliminary Observation of Speech Disorder in Obstructive and Mixed Sleep Apnea

Clinical observation suggested that speech disorder seemed to be associated with sleep apnea. We recorded a standard speech sample from 39 matched subjects in three groups, 13 sleep apnea individuals, 13 subjects with COPD, and 13 subjects without sleep apnea or COPD. Three speech pathologists in a single blind listening task of the recorded samples judged whether or not speech disorder was present. Eight of the sleep apnea subjects were judged to have disordered speech compared to three of the COPD group and one of the non-sleep apnea, non-COPD (normal) group. These results were statistically significant. This supports a clinical impression that speech disorder is more common in sleep apnea than expected. There may be common anatomic and physiologic disturbances present between the two conditions, and perhaps disordered speech is a sign of sleep apnea.

Reversal of Central Sleep Apnea Using Nasal CPAP

Based on the theory that obstructive (OSA) and central (CSA) sleep apneas share common pathophysiologic mechanisms, we attempted to treat eight patients with predominantly CSA by continuous positive airway pressure (CPAP). All patients exhibited repetitive episodes of CSA and mixed sleep apneas (MSA) in the supine position with a mean duration of 23.7 +/- 0.7 s and 34.5 +/- 1.3 s, respectively. The pattern of apnea changed when the subject lay in the lateral position. Five patients were observed to develop OSA in the lateral position with a mean duration of 27.2 +/- 1.5 s, while the other three patients snored continuously. High levels of CPAP (range 9.0 to 16.5 cm H2O) prevented all CSA and MSA and resulted in quiet breathing in all eight patients. Intermediate levels of CPAP produced firstly MSA, then purely OSA and/or continuous snoring. Low levels of nasal CPAP also prevented OSA and snoring occurring in the lateral posture in all subjects (range 2.0 to 8.3 cm H2O). Three patients are currently on home CPAP therapy for a range of four to 36 months. We conclude that upper airway collapse in the supine posture has a key role in the induction of CSA. We suggest that a reflex inhibition of respiration through activation of supraglottic mucosal receptors during passive oropharyngeal airway closure caused CSA in these patients.

Effect of Metabolic Acidosis Upon Sleep Apnea

The effects of metabolic acidosis upon the pattern of apnea during sleep were assessed in ten sleep apnea patients. Four had pure obstructive apnea, two pure central apnea, and four had mixed apnea. Acidosis was induced with acetazolamide. Acid-base shifts had little effect in pure obstructive and pure central apnea, but had a significant effect in mixed apnea. In two of the mixed apneic patients, metabolic acidosis converted predominantly central apnea into nearly pure obstructive apnea, prolonging apneic periods and worsening hypoxemia. A suggested explanation for this is the greater stimulating effect of acidosis upon the lower bellows muscles than upon the muscles which act to maintain patency of the upper airways. The observation that some patients with mixed sleep apnea appear to have central apnea while relatively alkalotic and obstructive apnea while acidotic emphasizes the need for more careful and detailed characterization of apneic disorders with respect to their responses to body states and therapeutic agents.