Oropharyngeal collapse predicts treatment response with oral appliance therapy in obstructive sleep apnea

STUDY OBJECTIVES: To examine whether primary oropharyngeal collapse of the upper airway during sleep predicts treatment success with oral appliance therapy in patients with obstructive sleep apnea. DESIGN: Prospective physiologic study. SETTING: Multidisciplinary sleep disorders clinic in a university teaching hospital. PATIENTS: Twelve treatment-na?ve adult patients with obstructive sleep apnea (apnea-hypopnea index > or = 10/h and at least 2 of the following symptoms: snoring, fragmented sleep, witnessed apneas, or daytime sleepiness). INTERVENTION: Custom-made mandibular advancement splint (MAS). MEASUREMENTS AND RESULTS: A baseline diagnostic polysomnogram confirmed AHI > or = 10 per hour. During the following acclimatization period, a custom-made adjustable MAS was incrementally advanced until maximum comfortable mandibular protrusion was reached. A second polysomnogram with MAS in situ determined efficacy. Following a 1-week washout period, a final sleep study was performed using multisensor catheters (with and without MAS, in random order during the same night) to determine upper-airway closing pressures and the site or sites of upper-airway collapse. MAS resulted in significant improvements, mean +/- SEM, in AHI (22.0 +/- 2.6 vs 9.2 +/- 1.9/h, p < .01) and upper-airway closing pressures during stage 2 non-rapid eye movement sleep (-1.1 +/- 0.3 vs -2.8 +/- 0.5 cm H2O, p < .01). All 4 patients with primary oropharyngeal collapse achieved an AHI < 5 per hour. Only 1 of the 8 patients with primary velopharyngeal collapse achieved an AHI < 5 per hour. Oropharyngeal collapse, compared with velopharyngeal collapse, predicted treatment success with MAS (p < .02). CONCLUSIONS: These preliminary data suggest that primary oropharyngeal collapse of the upper airway during sleep is an important predictor of treatment outcome with MAS therapy.     

Lateral sleeping position reduces severity of central sleep apnea / Cheyne-Stokes respiration

INTRODUCTION: The influence of sleeping position on obstructive sleep apnea severity is well established. However, in central sleep apnea with Cheyne Stokes respiration (CSA-CSR) in which respiratory-control instability plays a major pathophysiologic role, the effect of position is less clear. STUDY OBJECTIVES: To examine the influence of position on CSA-CSR severity as well as central and mixed apnea frequency. METHODS: Polysomnograms with digitized video surveillance of 20 consecutive patients with heart failure and CSA-CSR were analyzed for total apnea-hypopnea index, mean event duration, and mean oxygen desaturation according to sleep stage and position. Position effects on mixed and central apnea index, mean apnea duration, and mean desaturation were also examined in non-rapid eye movement sleep. RESULTS: Data are presented as mean +/- SEM unless otherwise indicated. Group age was 59.9 +/- 2.3 years, and total apnea-hypopnea index was 26.4 +/- 3.0 events per hour. Compared with supine position, lateral position reduced the apnea-hypopnea index in all sleep stages (Stage 1, 54.7 +/- 4.2 events per hour vs 27.2 +/- 4.1 events per hour [p < .001]; Stage 2, 43.3 +/- 6.1 events per hour vs 14.4 +/- 3.6 events per hour [p < .001]; slow-wave sleep, 15.9 +/- 6.4 events per hour vs 5.4 +/- 2.9 events per hour [p < .01]; rapid eye movement sleep, 38.0 +/- 7.3 events per hour vs 11.0 +/- 3.0 events per hour [p < .001]). Lateral position attenuated apnea and hypopnea associated desaturation (supine 4.7% +/- 0.3%, lateral 3.0% +/- 0.4%; p < .001) with no difference in event duration (supine 25.7 +/- 2.8 seconds, lateral 26.9 +/- 3.4 seconds; p = .921). Mixed apneas were longer than central (29.1 +/- 2.1 seconds and 19.3 +/- 1.1 seconds; p < .001) and produced greater desaturation (6.1% +/- 0.5% and 4.5% +/- 0.5%, p = .003). Lateral position decreased desaturation independent of apnea type (supine 5.4% +/- 0.5%, lateral 3.9% < or = 0.4%; p = .003). CONCLUSIONS: Lateral position attenuates severity of CSA-CSR. This effect is independent of postural effects on the upper airway and is likely to be due to changes in pulmonary oxygen stores. Further studies are required to investigate mechanisms involved.     

Effect of zolpidem on the efficacy of continuous positive airway pressure as treatment for obstructive sleep apnea

STUDY OBJECTIVE: Assess the effect of the hypnotic zolpidem on the efficacy of nasal continuous positive airway pressure for treatment of Obstructive Sleep Apnea. DESIGN: Randomized double blind placebo controlled, cross-over study. SETTING: Veterans Administration Medical Center. PATIENTS: 16 patients with severe obstructive sleep apnea (apnea+ hypopnea index > 30/hr), on CPAP therapy for at least 6 months. INTERVENTION: Three sleep studies were performed over three consecutive weeks. On night one the pressure level required to prevent apnea, hypopnea, and snoring was determined. On the second and third study nights, either placebo (P) or 10 mg of zolpidem (Z) was given (random order) and subjects slept on the CPAP level determined on the first night. MEASUREMENTS: Sleep architecture, apnea + hypopnea index, arterial oxygen saturation. RESULTS: The sleep architecture was similar on the placebo and zolpidem nights except for a decrease in the sleep latency ( P: 23.5 +/- 4.7; Z: 13.1 +/- 3.3 minutes, P < 0.02) and a small decrease in the arousal index (P < 0.03) on zolpidem nights. The was no significant difference between placebo and zolpidem nights in the apnea + hypopnea index (P: 4.8 +/- 1.4 versus Z : 2.7 +/- 0.47 events/hour), oxygen desaturation index (1.46 +/- 0.53 versus 0.81 +/- 0.29 desaturations/hour), or the lowest SaO2 (91.4 +/- 0.6 versus 91.0 +/- 0.7%). CONCLUSIONS: Acute administration of zolpidem 10 mg does not impair the efficacy of an effective level of CPAP in patients with severe obstructive sleep apnea.     

A randomized, double-blind clinical trial comparing continuous positive airway pressure with a novel bilevel pressure system for treatment of obstructive sleep apnea syndrome

STUDY OBJECTIVES: To obtain efficacy, objective compliance, and self-assessment data from obstructive sleep apnea syndrome (OSAS) patients treated with continuous positive airway pressure (CPAP) or a novel bilevel (NBL) therapy. DESIGN: Randomized, controlled, double-blind trial. SETTING: Home treatment after diagnosis and titration by split-night polysomnography (PSG) in a sleep laboratory. PATIENTS: Twenty-seven adults (22 men) newly referred for suspected OSAS but without concomitant medical or sleep disorders. INTERVENTIONS: If the subject's apnea-hypopnea index was greater than 10 and less than 100, the CPAP was titrated during PSG and then followed by NBL titration. Treatment was randomly and blindly set to either CPAP or NBL mode for 1 month. MEASUREMENTS & RESULTS: There were no significant baseline group differences in age, body mass index, apnea-hypopnea index (mean +/- SD, CPAP group vs NBL group of 46.1 +/- 23.1/hour vs 41.8 +/- 25.8), CPAP requirement, or scores on the Epworth Sleepiness Scale and Functional Outcomes of Sleep Questionnaire. Treatment with CPAP and NBL equivalently reduced the apnea-hypopnea index during the laboratory titration (7.6 +/- 11.9/hour vs. 3.7 +/- 4.4, respectively). At 1 month, there were no significant group compliance differences as determined by percentage of nights with at least 4 hours of use (CPAP, 80.5 +/- 24 vs NBL, 77.6 +/- 24.8) and hours of use per night (CPAP, 5.6 +/- 1.4 hours/night vs NBL, 5.6 +/- 1.7). Similar improvements were seen in scores on the Epworth Sleepiness Scale and Functional Outcomes of Sleep Questionnaire. CONCLUSIONS: The NBL appeared to be as effective as CPAP for the treatment of OSAS but offered no advantages in patients receiving first-time therapy for OSAS.     

Rapid maxillary expansion in children with obstructive sleep apnea syndrome

OBJECTIVE: To evaluate the effect of rapid maxillary expansion on children with nasal breathing and obstructive sleep apnea syndrome. METHOD: Recruitment of children with maxillary contraction, without of adenoid hypertrophy, with a body mass index < 24 kg/m2, with obstructive sleep apnea syndrome demonstrated by polysomnography, and whose parents signed informed consent. Otolaryngologic and orthognathic-odontologic evaluation with clinical evaluation, anterior rhinometry and nasal fibroscopy, panoramic radiographs, anteroposterior and laterolateral telecephalometry were performed at entry and follow-up. Intervention: Rapid maxillary expansion (ie, active phase of treatment) was performed for 10 to 20 days; maintenance of device (for consolidation) and orthodontic treatment on teeth lasted 6 to 12 months. RESULTS: 31 children (19 boys), mean age 8.7 years, participated in the study. The mean apnea-hypopnea index was 12.2 events per hour. At the 4-month follow-up, the anterior rhinometry was normal, and all children had an apnea-hypopnea index < 1 event per hour. The mean cross-sectional expansion of the maxilla was 4.32 +/- 0.7 mm. There was a mean increase of the pyriform opening of 1.3 +/- 0.3 mm. CONCLUSION: Rapid maxillary expansion may be a useful approach in dealing with abnormal breathing during sleep.     

Severity of sleep-disordered breathing improves following parturition

STUDY OBJECTIVE: Changes in sleep-disordered breathing associated with late pregnancy have not previously been systematically investigated; however, a number of case reports indicate exacerbation of obstructive sleep apnea in late pregnancy, often in association with maternal hypertension. We aimed to compare the severity of sleep-disordered breathing and associated maternal blood-pressure responses in late pregnancy with the nonpregnant state. DESIGN: Case-controlled, longitudinal study of sleep-disordered breathing during late pregnancy and postpartum. Study Patients: Ten women referred for suspected sleep-disordered breathing during the third trimester of pregnancy. INTERVENTIONS: None. MEASUREMENTS AND RESULTS: Full overnight polysomnography and continuous systemic blood pressure were measured during the third trimester of pregnancy and 3 months following delivery. Parameters of sleep-disordered breathing, including apnea hypopnea index and minimum overnight arterial oxyhemoglobin saturation, were compared between antenatal and postnatal studies. An improvement in both apnea-hypopnea index and minimum arterial oxyhemoglobin saturation occurred consistently in all subjects postnatally. In non-rapid eye movement sleep, mean apnea-hypopnea index was reduced from 63 +/- 15 per hour antenatally to 18 +/- 4 per hour postnatally (P = .03), and in rapid eye movement sleep, from 64 +/- 11 per hour to 22 +/- 4 per hour (P = .002). Minimum arterial oxyhemoglobin saturation was increased from 86% +/- 2% antenatally to 91% +/- 1% postnatally (P = .01). Arterial blood-pressure responses to apnea peaked at 170 to 180 mm Hg antenatally, while they only peaked at 130 to 140 mm Hg postnatally. CONCLUSION: This study indicates that late pregnancy may be associated with increased severity of sleep-disordered breathing and associated blood-pressure responses.     

Oral appliance therapy reduces blood pressure in obstructive sleep apnea: a randomized, controlled trial

STUDY OBJECTIVE: To investigate the short-term effect (4 weeks) of oral appliance therapy for obstructive sleep apnea on blood pressure. DESIGN: Randomized, controlled, crossover trial. SETTING: Multidisciplinary sleep disorders clinic in a university teaching hospital. PATIENTS: Sixty-one patients diagnosed with obstructive sleep apnea on polysomnography (apnea hypopnea index > or = 10 per hour and at least 2 of the following symptoms--daytime sleepiness, snoring, witnessed apneas, fragmented sleep; age > 20 years; and minimum mandibular protrusion of 3 mm). INTERVENTION: A mandibular advancement splint (MAS) and control oral appliance for 4 weeks each. MEASUREMENTS AND RESULTS: Polysomnography and 24-hour ambulatory blood pressure monitoring were carried out at baseline and following each 4-week intervention period. Patients showed a 50% reduction in mean apnea hypopnea index with MAS compared with the control and a significant improvement in both minimum oxygen saturation and arousal index. There was a significant reduction with the MAS in mean (+/- SEM) 24-hour diastolic blood pressure (1.8 +/- 0.5 mmHg) compared with the control (P = .001) but not in 24-hour systolic blood pressure. Awake blood-pressure variables were reduced with the MAS by an estimated mean (+/- SEM) of 3.3 +/- 1.1 mmHg for systolic blood pressure (P = .003) and 3.4 +/- 0.9 mmHg for diastolic blood pressure (P < .0001). There was no significant difference in blood pressure measured asleep. CONCLUSION: Oral appliance therapy for obstructive sleep apnea over 4 weeks results in a reduction in blood pressure, similar to that reported with continuous positive airway pressure therapy.     

Effect of expiratory positive airway pressure on sleep disordered breathing

STUDY OBJECTIVES: We sought to determine the effect of expiratory positive airway pressure on end expiratory lung volume (EELV) and sleep disordered breathing in obstructive sleep apnea patients. DESIGN: Observational physiology study PARTICIPANTS: We studied 10 OSA patients during sleep wearing a facial mask. We recorded 1 hour of NREM sleep without treatment (baseline) and 1 hour with 10 cm H2O EPAP in random order, while measuring EELV and breathing pattern. RESULTS: The mean EELV change between baseline and EPAP was only 13.3 mL (range 2-25 mL). Expiratory time was significantly increased with EPAP compared to baseline 2.64 +/- 0.54 vs 2.16 +/- 0.64 sec (P = 0.002). Total respiratory time was longer with EPAP than at baseline 4.44 +/- 1.47 sec vs 3.73 +/- 0.88 sec (P = 0.3), and minute ventilation was lower with EPAP vs baseline 7.9 +/- 4.17 L/min vs 9.05 +/- 2.85 L/min (P = 0.3). For baseline (no treatment) and EPAP respectively, the mean apnea+hypopnea index (AHI) was 62.6 +/- 28.7 and 56.8 +/- 30.3 events per hour (P = 0.4). CONCLUSION: In OSA patients during sleep, the application of 10 cm H2O EPAP led to prolongation of expiratory time with only marginal increases in FRC. These findings suggest important mechanisms exist to avoid hyperinflation during sleep.     

Differences between men and women in the clinical presentation of patients diagnosed with obstructive sleep apnea syndrome

STUDY OBJECTIVES: Obstructive sleep apnea syndrome (OSAS) results from recurrent episodes of breathing cessation during sleep. Epidemiologic studies have shown that OSAS is more prevalent in men than women (4% vs 2%). Previous studies have explored gender-related differences in upper airway anatomy and function, hormone physiology, and polysomnographic findings. The aim of this study is to assess differences in clinical presentation between women and men with OSAS. DESIGN: Retrospective chart review analysis. SETTING: Tertiary university-based medical center PARTICIPANTS: 130 randomly selected women with OSAS matched individually with 130 men with OSAS for age, body mass index, apnea-hypopnea index, and Epworth Sleepiness Scale score. INTERVENTIONS: N/A. MEASUREMENTS AND RESULTS: Data were obtained from questionnaires and in-laboratory polysomnographic studies. There were no differences between the genders for age (48.0 +/- 1.1 years [mean +/- SEM] for women vs 47.6 +/- 1.0 years for men), body mass index (40.4 +/- 0.7 kg/m2 for women vs 40.0 +/- 0.6 kg/m2 for men), apnea-hypopnea index (36.8 +/- 3.3/hour for women vs 36.0 +/- 3.0/hour for men), or Epworth Sleepiness Scale score (12.45 +/- 0.53 for women vs 12.84 +/- 0.47 for men). Although snoring and sleepiness were similarly common in women and men, women more often described their main presenting symptoms as insomnia (odds ratio: 4.20; 95% confidence interval: 1.54-14.26) and were much more likely to have a history of depression (odds ratio: 4.60; 95% confidence interval: 1.71-15.49) and hypothyroid disease (odds ratio: 5.60; 95% confidence interval: 2.14-18.57). Women presented less often with a primary complaint of witnessed apnea (odds ratio: 0.66; 95% confidence interval: 0.38-1.12), consumed less caffeine per day (3.3 cups in women vs 5.2 cups in men; P = .0001), and admitted to less alcohol consumption (odds ratio: 0.36; 95% confidence interval: 0.18-0.70). CONCLUSIONS: At the time of OSAS diagnosis, women with OSAS are more likely to be treated for depression, to have insomnia, and to have hypothyroidism than are men with the same degree of OSAS.     

Relationship of sleep apnea to functional capacity and length of hospitalization following stroke

STUDY OBJECTIVES: Recent evidence indicates that sleep apnea is common in patients with stroke. We hypothesized that the presence of sleep apnea among stroke patients would be associated with a greater degree of functional disability and longer hospitalization following stroke. DESIGN: Prospective study. SETTING AND PATIENTS: Sixty-one stroke patients admitted to a stroke rehabilitation unit. INTERVENTIONS: N/A. MEASUREMENTS AND RESULTS: Sleep studies were performed on all patients, and sleep apnea was defined as an apnea-hypopnea index of 10 or more per hour of sleep. Patients underwent functional assessments, including the Functional Independence Measure. Sleep apnea was found in 72% of patients; 60% had predominantly obstructive sleep apnea, while 12% had predominantly central sleep apnea. Although the severity of stroke was similar in the 2 groups, compared to patients without sleep apnea, those with sleep apnea had lower functional capacity [Functional Independence Measure score (mean +/- SEM) 80.2 +/- 3.6 versus 94.7 +/- 4.3, p < 0.05 at admission, and 101.5 +/- 2.8 versus 112.9 +/- 2.7, p < 0.05 at discharge] and spent significantly more days in rehabilitation (45.5 +/- 2.3 versus 32.1 +/- 2.7 days, p < 0.005). In addition, multiple regression analysis showed that obstructive sleep apnea was significantly and independently related to functional impairment and length of hospitalization. CONCLUSIONS: Sleep apnea is very common among stroke patients undergoing rehabilitation, and its presence is associated with worse functional impairment and a longer period of hospitalization and rehabilitation. These data suggest that sleep apnea may be contributing to functional impairment and prolonged hospitalization following stroke.     

Endothelial dysfunction in obstructive sleep apnea measured by peripheral arterial tone response in the finger to reactive hyperemia

STUDY OBJECTIVE: The aim of this study was to investigate endothelial functioning in sleep apnea patients using a novel plethysmographic device that monitors peripheral arterial tone response in the finger to reactive hyperemia induced by forearm ischemia. PARTICIPANTS: Forty-six sleep apnea patients, 74.0% men, mean age 46.8 +/- 9.3 years, and 17 control subjects without sleep apnea, 64.7% men, mean age 47.1 +/- 6.7 years. SETTING: Eight-bed Technion Sleep Medicine Center in Haifa, Israel. DESIGN: Endothelial functioning assessed by the reactive hyperemia peripheral arterial tone index was measured twice, before sleep and after waking from sleep monitored by polysomnography in the laboratory. The reactive hyperemia peripheral arterial tone index was calculated as the average amplitude of the peripheral arterial tone signal after the cuff deflation divided by the average amplitude before the cuff inflation. RESULTS: Morning index of endothelial functioning was significantly lower in patients with moderate to severe sleep apnea (apnea-hypopnea index > or = 30) than in patients with mild sleep apnea (30 < apnea-hypopnea index < or = 10) and in the control group without sleep apnea (apnea-hypopnea index < 10). The morning index was significantly inversely correlated with apnea-hypopnea index. Patients with a history of hypertension or cardiovascular disease had significantly lower morning and evening indexes of endothelial functioning than patients without such a history. Multivariate analysis revealed that apnea-hypopnea index and sleep efficiency were significant predictors of the morning index. CONCLUSION: Measurements of the response of the peripheral arterial tone in the finger to reactive hyperemia can be used as a substitute for the brachial artery ultrasound technique to measure endothelial functioning in patients with sleep apnea.     

Validation of a new system of tracheal sound analysis for the diagnosis of sleep apnea-hypopnea syndrome

STUDY OBJECTIVES: To evaluate the validity of a novel method of using tracheal sound analysis for the diagnosis of sleep apnea-hypopnea syndrome. DESIGN: Retrospective analysis in consecutive patients. SETTING: A sleep clinic in a general hospital. PATIENTS: A total of 383 patients who were referred for suspected sleep apnea-hypopnea syndrome and underwent diagnostic polysomnography with sufficient quality. INTERVENTIONS: N/A. MEASUREMENTS AND RESULTS: Ordinary polysomnography with simultaneous tracheal sound recording was performed. The apnea-hypopnea index (AHI) was calculated as the number of apnea and hypopnea events per hour of sleep. Tracheal sounds were digitized and recorded as power spectra. An automated computer program detected transient falls (TS-dip) in the time series of moving average of the logarithmic power of tracheal sound. We defined the tracheal sound-respiratory disturbance index (TS-RDI) as the number of TS-dips per hour of examination. We also calculated the oxygen desaturation index (the number of SaO2 dips of at least 4% per hour of examination). The TS-RDI highly correlated with AHI (r = 0.93). The mean (+/- SD) difference between the TS-RDI and AHI was -8.4 +/- 10.4. The diagnostic sensitivity and specificity of the TS-RDI when the same cutoff value was used as for AHI were 93% and 67% for the AHI cutoff value of 5 and 79% and 95% for the AHI cutoff value of 15. The agreement between the TS-RDI and AHI was better than that between the oxygen desaturation index and AHI. CONCLUSIONS: The fully automated tracheal sound analysis demonstrated a relatively high performance in the diagnosis of sleep apnea-hypopnea syndrome. We think that this method is useful for the portable monitoring of sleep apnea-hypopnea syndrome.     

Prevalence of persistent sleep apnea in patients treated with continuous positive airway pressure

STUDY OBJECTIVE: There are limited data on the prevalence of persistent obstructive sleep apnea (OSA) in patients who are clinically asymptomatic with continuous positive airway pressure (CPAP). Our objectives were to estimate the prevalence of persistent OSA and to explore the parameters that may be capable of discriminating these patients. DESIGN: Prospective survey. SETTING: A tertiary-care sleep-disorders clinic. PARTICIPANTS: Consecutive patients treated with single-pressure CPAP for at least 3 months were studied. All had undergone CPAP titrations and were compliant with treatment. They denied snoring or persistent excessive daytime somnolence. Of 114 who qualified, 101 were studied. INTERVENTIONS: Subjects underwent 16-channel polysomnography with electroencephalogram and pneumotachometer while using their CPAP. MEASUREMENTS AND RESULTS: Seventeen of 101 subjects (17%) had an apnea-hypopnea index of over 10. Fifty-one had only split-night protocols for CPAP titration. There was no significant difference between participants with persistent OSA and those with an apnea-hypopnea index < 5 with regard to age, sex, time since diagnosis, reported snoring, change in weight, or quality of life (all p > .10). Mean current CPAP level was higher, with a mean +/- SD 10.6 +/- 2.8 versus 8.6 +/- 2.3 cm H2O (p = .002). Unresolved air leak related to CPAP was more frequent in the patients with persistent OSA. Morning headaches, nonrestorative sleep, and frequent central apneas on the CPAP titration were all associated with persistent OSA. CONCLUSIONS: Persistent OSA is frequent in patients treated with CPAP. This is more frequent in patients with high body mass index, higher prescribed pressures, and unresolved mask leak.     

Improvement of sleep apnea in patients with chronic renal failure who undergo nocturnal hemodialysis

BACKGROUND: Sleep apnea is common in patients with chronic renal failure and is not improved by either conventional hemodialysis or peritoneal dialysis. With nocturnal hemodialysis, patients undergo hemodialysis seven nights per week at home while sleeping. We hypothesized that nocturnal hemodialysis would correct sleep apnea in patients with chronic renal failure because of its greater effectiveness. METHODS: Fourteen patients who were undergoing conventional hemodialysis for four hours on each of three days per week underwent overnight polysomnography. The patients were then switched to nocturnal hemodialysis for eight hours during each of six or seven nights a week. They underwent polysomnography again 6 to 15 months later on one night when they were undergoing nocturnal hemodialysis and on another night when they were not. RESULTS: The mean (+/-SD) serum creatinine concentration was significantly lower during the period when the patients were undergoing nocturnal hemodialysis than during the period when they were undergoing conventional hemodialysis (3.9+/-1.1 vs. 12.8+/-3.2 mg per deciliter [342+/-101 vs. 1131+/-287 micromol per liter], P<0.001). The conversion from conventional hemodialysis to nocturnal hemodialysis was associated with a reduction in the frequency of apnea and hypopnea from 25+/-25 to 8+/-8 episodes per hour of sleep (P=0.03). This reduction occurred predominantly in seven patients with sleep apnea, in whom the frequency of episodes fell from 46+/-19 to 9+/-9 per hour (P= 0.006), accompanied by increases in the minimal oxygen saturation (from 89.2+/-1.8 to 94.1+/-1.6 percent, P=0.005), transcutaneous partial pressure of carbon dioxide (from 38.5+/-4.3 to 48.3+/-4.9 mm Hg, P=0.006), and serum bicarbonate concentration (from 23.2+/-1.8 to 27.8+/-0.8 mmol per liter, P<0.001). During the period when these seven patients were undergoing nocturnal hemodialysis, the apnea-hypopnea index measured on nights when they were not undergoing nocturnal hemodialysis was greater than that on nights when they were undergoing nocturnal hemodialysis, but it still remained lower than it had been during the period when they were undergoing conventional hemodialysis (P=0.05). CONCLUSIONS: Nocturnal hemodialysis corrects sleep apnea associated with chronic renal failure.     

Auto-CPAP therapy for obstructive sleep apnea: induction of microarousals by automatic variations of CPAP pressure?

STUDY OBJECTIVES: To investigate the frequency of microarousals (MA) associated with pressure changes during auto-CPAP therapy (APAP) for obstructive sleep apnea (OSA). DESIGN: Patients with OSA were studied by polysomnography during APAP therapy (Somnosmart). The MA were classified on the basis of concomitant changes in APAP pressure. SETTING: Sleep laboratory of a university hospital PARTICIPANTS: 30 patients with moderate to severe OSA. MEASUREMENTS AND RESULTS: The mean AHI during APAP was 4.7+/-4.7, the mean arousal index was 14.5+/-6.6 per hour. During epochs with a pressure variation greater than 0.5 mbar, significantly more MA occurred (0.30+/-0.17 MA per epoch) than in epochs with constant treatment pressure (0.10+/-0.054 MA per epoch; p<0.001). There were more MA during pressure-increase epochs than during pressure-decrease epochs (0.42+/-0.24 vs. 0.16+/-0.12 MA per epoch; p<0.001). 82.5 percent of the MA were not preceded by a significant change in pressure (at least 0.5 mbar within 30 sec.), 10.6% were associated with a significant prior increase and 6.9% with a significant prior decrease in pressure. The percentage of MA preceded by a significant pressure variation varied between 2.3% and 61%, with a mean of 18.9%. CONCLUSIONS: The overall frequency of MA was low, and in most individuals the relative amount of "pressure-associated MA" was not significant. However in some individuals it cannot be excluded that some additional MA may have been induced by pressure variations. Should it prove possible to prevent such "pressure-associated MA" by optimizing the regulation of APAP pressure, the overall clinical effect of APAP treatment may be improved.     

Association between atrial fibrillation and central sleep apnea

BACKGROUND: We previously described an association between atrial fibrillation and central sleep apnea in a group of patients with congestive heart failure. We hypothesized that the prevalence of atrial fibrillation might also be increased in patients with central sleep apnea in the absence of other cardiac disease. METHODS AND RESULTS: We compared the prevalence of atrial fibrillation in a series of 60 consecutive patients with idiopathic central sleep apnea (apnea-hypopnea index > 10 events per hour, > 50% central events) with that in 60 patients with obstructive sleep apnea (apnea-hypopnea index > 10, > 50% obstructive events) and 60 patients without sleep apnea (apnea-hypopnea index < 10), matched for age, sex, and body mass index. Subjects with a history of congestive heart failure, coronary artery disease, or stroke were excluded from the study. The prevalence of atrial fibrillation among patients with idiopathic central sleep apnea was found to be significantly higher than the prevalence among patients with obstructive sleep apnea or no sleep apnea (27%, 1.7%, and 3.3%, respectively, P < .001). However, hypertension was most common and oxygen desaturation most extreme among patients with obstructive sleep apnea. CONCLUSIONS: We conclude that there is a markedly increased prevalence of atrial fibrillation among patients with idiopathic central sleep apnea in the absence of congestive heart failure. Moreover, the high prevalence of atrial fibrillation among patients with idiopathic central sleep apnea is not explainable by the presence of hypertension or nocturnal oxygen desaturation, since both of these were more strongly associated with obstructive sleep apnea.     

Severe obstructive sleep apnea/hypopnea mimicking REM sleep behavior disorder

OBJECTIVE: To describe the clinical and video-polysomnographic (VPSG) features of a group of subjects with severe obstructive sleep apnea/hypopnea (OSAH) mimicking the symptoms of REM sleep behavior disorder (RBD). DESIGN: Evaluation of clinical and VPSG data. SETTING: University hospital sleep laboratory unit. PARTICIPANTS: Sixteen patients that were identified during routine first evaluation visits. Patients' PSG measures were compared with those of 20 healthy controls and 16 subjects with idiopathic RBD of similar age and sex distribution and apnea/hypopnea index lower than 10. INTERVENTIONS: NA. RESULTS: Sixteen subjects were identified presenting with dream-enacting behaviors and unpleasant dreams suggesting the diagnosis of RBD, in addition to snoring and excessive daytime sleepiness. VPSG excluded RBD showing REM sleep with atonia and without increased phasic EMG activity, and was diagnostic of severe OSAH with a mean apnea-hypopnea index of 67.5 +/- 18.7 (range, 41-105) demonstrating that the reported abnormal sleep behaviors occurred only during apnea-induced arousals. Continuous positive airway pressure therapy eliminated the abnormal behaviors, unpleasant dreams, snoring and daytime hypersomnolence. CONCLUSIONS: Our study shows that severe OSAH may mimick the symptoms of RBD and that VPSG is mandatory to establish the diagnosis of RBD, and identify or exclude other causes of dream-enacting behaviors.     

Complex sleep apnea syndrome: is it a unique clinical syndrome?

STUDY OBJECTIVES: Some patients with apparent obstructive sleep apnea hypopnea syndrome (OSAHS) have elimination of obstructive events but emergence of problematic central apneas or Cheyne-Stokes breathing pattern. Patients with this sleep-disordered breathing problem, which for the sake of study we call the "complex sleep apnea syndrome," are not well characterized. We sought to determine the prevalence of complex sleep apnea syndrome and hypothesized that the clinical characteristics of patients with complex sleep apnea syndrome would more nearly resemble those of patients with central sleep apnea syndrome (CSA) than with those of patients with OSAHS. DESIGN: Retrospective review SETTING: Sleep disorders center. PATIENTS OR PARTICIPANTS: Two hundred twenty-three adults consecutively referred over 1 month plus 20 consecutive patients diagnosed with CSA. INTERVENTIONS: NA. MEASUREMENTS AND RESULTS: Prevalence of complex sleep apnea syndrome, OSAHS, and CSA in the 1-month sample was 15%, 84%, and 0.4%, respectively. Patients with complex sleep apnea syndrome differed in gender from patients with OSAHS (81% vs 60% men, p < .05) but were otherwise similar in sleep and cardiovascular history. Patients with complex sleep apnea syndrome had fewer maintenance-insomnia complaints (32% vs 79%; p < .05) than patients with CSA but were otherwise not significantly different clinically. Diagnostic apnea-hypopnea index for patients with complex sleep apnea syndrome, OSAHS, and CSA was 32.3 +/- 26.8, 20.6 +/- 23.7, and 38.3 +/- 36.2, respectively (p = .005). Continuous positive airway pressure suppressed obstructive breathing, but residual apnea-hypopnea index, mostly from central apneas, remained high in patients with complex sleep apnea syndrome and CSA (21.7 +/- 18.6 in complex sleep apnea syndrome, 32.9 +/- 30.8 in CSA vs 2.14 +/- 3.14 in OSAHS; p < .001). CONCLUSIONS: Patients with complex sleep apnea syndrome are mostly similar to those with OSAHS until one applies continuous positive airway pressure. They are left with very disrupted breathing and sleep on continuous positive airway pressure. Clinical risk factors don't predict the emergence of complex sleep apnea syndrome, and best treatment is not known.     

Obstructive sleep apnea in Costello syndrome

Costello syndrome (CS) was initially described by Costello in 1971; it is caused by a germline mutation in HRAS proto-oncogene. The aim of the present study was to evaluate the respiratory activity during sleep in a group of subjects with CS. We studied 10 consecutive patients, 4 males and 6 females, aged 3-29 years, affected by CS. All patients underwent clinical, neurological, otholaryngologic and radiologic evaluation, and a full-night polysomnography in the sleep laboratory. Polysomnography showed that seven patients presented a relevant number of respiratory events of obstructive type during sleep. The apnea-hypopnea index (AHI) ranged from 0 to 19.2 events per hour (mean index = 7.5 +/- 6.9 events/hr). In one patient AHI was not evaluable because of tracheostomy. Apnea induced mild or moderate hemoglobin desaturations (mean of lowest SpO2 values = 85.4 +/- 5.5%). Only sporadic respiratory pauses of central type were observed (mean number of central apnea per study: 7.2 +/- 6.8 events/hr). Sleep structure was fragmented, with a high number of awakenings (mean number of awakenings was 13.2 +/- 8.1; of these, 4.8 +/- 2.5 lasted longer than 2 min). In all patients, otolaryngologic and radiologic observations revealed one or more sites of narrowing in the upper airways. Our results suggest that Costello patients have a high prevalence of obstructive sleep-related respiratory disorders, which need to be assessed by means of polysomnography.     

Effects and Side-Effects of Surgery for Snoring and Obstructive Sleep Apnea – A Systematic Review

Study Objectives:

Many patients undergo surgery for snoring and sleep apnea, although the efficacy and safety of such procedures have not been clearly established. Our aim was systematically to review studies of the efficacy and adverse effects of surgery for snoring and obstructive sleep apnea.

Design:

Systematic review.

Measurements:

PubMed and Cochrane databases were searched in September 2007. Randomized controlled trials of surgery vs. sham surgery or conservative treatment in adults, with daytime sleepiness, quality of life, apnea-hypopnea index, and snoring as outcomes were included. Observational studies were also reviewed to assess adverse effects. Evidence of effect required at least two studies of medium and high quality reporting the same result.

Results:

Four studies of benefits and 45 studies of adverse effects were included. There was no significant effect on daytime sleepiness and quality of life after laser-assisted uvulopalatoplasty and radiofrequency ablation. The apnea-hypopnea index and snoring was reduced in one trial after laser-assisted uvulopalatoplasty but not in another trial. Subjective snoring was reduced in one trial after radiofrequency ablation. No trial investigating the effect of any other surgical modality met the inclusion criteria. Persistent side-effects occurred after uvulopalatopharyngoplasty and uvulopalatoplasty in about half the patients and difficulty in swallowing, globus sensation and voice changes were especially common.

Conclusions:

Only a small number of randomized controlled trials with a limited number of patients assessing some surgical modalities for snoring or sleep apnea are available. These studies do not provide any evidence of effect from laser-assisted uvulopalatoplasty or radiofrequency ablation on daytime sleepiness, apnea reduction, quality of life or snoring. We call for research of randomized, controlled trials of surgery other than uvulopalatopharyngoplasty and uvulopalatoplasty, as they are related to a high risk of long-term side-effects, especially difficulty swallowing.

Citation:

Franklin KA; Anttila H; Axelsson S; Gislason T; Maasilta P; Myhre KI; Rehnqvist N. Effects and side-effects of surgery for snoring and obstructive sleep apnea – a systematic review. SLEEP 2009;32(1):27–36.