Comparison of respiratory polysomnographic parameters in matched cohorts of upper airway resistance and obstructive sleep apnea syndrome patients.

OBJECTIVE: To compare respiratory nocturnal polysomnography (NPSG) characteristics between matched cohorts of upper airway resistance syndrome (UARS) and obstructive sleep apnea syndrome (OSAS) patients. METHODS: All patients received 13-channel NPSG, including esophageal pressure (Pes) manometry. By definition, OSAS patients had an apnea-hypopnea index (AHI, number of apneas/hypopneas per hour total sleep time) > or = 15, and UARS patients had an AHI < 5. Respiratory effort-related arousal (RERA) was defined as the absence of apnea/hypopnea with > or = 10 s duration of progressive negative Pes, culminating in an arousal or microarousal. UARS patients, by definition, had > or = 15 RERAs per hour. Fifteen consecutively diagnosed UARS patients were matched with OSAS patients on the basis of body mass index (BMI) and gender. RESULTS: Respiratory disturbance index (sum of the AHI and RERA per hour) was the same for both cohorts: UARS, 36+/-4; OSAS, 42+/-6 (p = 0.34). There were no differences between cohorts for mean inspiratory Pes nadirs for each 30-s epoch of sleep compared for each sleep stage over an entire night. For randomly selected breaths from supine stage 2 sleep, the mean inspiratory Pes nadir was the same for the cohorts: UARS, -16.6+/-2 cm H2O; OSAS, -16.1+/-3 cm H2O (p = 0.30). Differences between cohorts for each parameter fell within respective 95% confidence intervals. CONCLUSION: With the exception of AHI, respiratory NPSG parameters were the same for UARS and OSAS patients when BMI and gender were controlled for.     

Maintenance of wakefulness test in military personnel with upper airway resistance syndrome and mild to moderate obstructive sleep apnea

Background  Sleep-disordered breathing (SDB) and the associated symptom of excessive daytime sleepiness (EDS) in military personnel has influential consequences in both the garrison and the deployed environments. The maintenance of wakefulness test (MWT) is a daytime study used to evaluate the tendency to stay awake. We evaluated consecutive patients diagnosed with mild to moderate obstructive sleep apnea (OSA) and upper airway resistance syndrome (UARS) to provide an objective measure of their EDS using the MWT. Materials and methods  All military personnel referred between February 2004 and March 2005 with a clinical evaluation suspicious for SDB were evaluated with an overnight polysomnography (PSG). After overnight PSG, military personnel with mild to moderate OSA and UARS were evaluated with a 40-min protocol MWT. Abnormal MWT was defined as sleep onset latency mean below 19.4 min (<2 SD below the mean). Results  Sixty-two military personnel met entry criteria. Fifty-nine were men. Nineteen patients (32%) were diagnosed with UARS with a mean respiratory disturbance index of 11/h (5–20/h). Forty-one (68%) of the military personnel had OSA with a mean apnea–hypopnea index of 12/h (5–29/h). As a collective group, the mean Epworth Sleepiness Scale was elevated at 13/24 (1–24). This subjective excessive sleepiness was assessed with the MWT test, which resulted in a group mean MWT sleep onset latency of 27 min (5–40 min). Eighteen soldiers (30% of the total patients) had abnormal MWTs [six patients (33.3%) with UARS and 12 (67%) with OSA]. Conclusion  Military personnel with mild to moderate OSA and UARS often have abnormal MWTs and therefore have a pathological tendency to fall asleep. This EDS could pose a safety hazard in those personnel, military or civilian, who operate dangerous vehicles, machinery, or carry a firearm. Military personnel with untreated SDB are also at risk for the consequences of decreased mental alertness and decreased cognitive functioning due to daytime sleepiness. All work was completed at the Brooke Army Medical Center, Fort Sam Houston, Texas. The opinions expressed herein are those of the authors and should not be construed as official or reflecting the policy of either the Department of the Army, Department of Defense, or the US Government.     

Comparison of nasal prong pressure and thermistor measurements for detecting respiratory events during sleep

INTRODUCTION AND OBJECTIVES: Thermistor (TH) measurements have been traditionally used to determine airflow during polysomnographic studies (PSG). However, low accuracy in detecting hypopneas is a major drawback. Nasal prong pressure (NPP) measurements are becoming increasingly popular for quantifying respiratory events during sleep. We prospectively compared NPP and TH measurements with respect to their ability to detect respiratory events during routine PSG. METHODS: Forty consecutive patients (26 male, 14 female) with clinically suspected sleep-disordered breathing (SDB) underwent routine diagnostic PSG. Airflow was measured using NPP and TH devices simultaneously. PSG was scored manually according to R and K criteria. Respiratory events were scored in two passes. During the first pass, the TH signal was disabled and the NPP signal was scored. During the second pass, the NPP signal was disabled and the TH signal was scored. Scorers for one method were blinded from the results of the other method. To assess respiratory events, we used the respiratory arousal index (RAI), which was defined as the number of apneas and/or hypopneas followed by an arousal per hour of sleep, as detected by TH (RAI-TH) or NPP (RAI- NPP). Agreement analysis of the results obtained using the two different techniques was performed using the methodology of Bland-Altman. RESULTS: Twenty-six patients had obstructive sleep apnea, 10 had respiratory effort-related arousals and 4 had habitual snoring. The failure time of the flow signal on the raw data was not different between the two methods (NPP: 6 +/- 13 min, TH: 4 +/- 7 min). The Bland-Altman analysis of RAIs demonstrated that more events were nearly always detected using NPP compared to TH devices (44.4 +/- 37 vs. 35.4 +/- 31, p < 0.001). No difference in the index of central apneas between the two methods could be detected. Sleep position had no effect on either measurement method. CONCLUSIONS: NPP measurements are superior to TH measurements for detecting obstructive respiratory events during sleep. Measurement of NPP is a simple, practical, sensitive and reliable method for detecting the whole spectrum of SDB. We recommend incorporating nasal prongs in routine polysomnographic monitoring.     

Somatic arousal and sleepiness/fatigue among patients with sleep-disordered breathing

Objectives

In a large clinical sample, we tested the hypothesis that levels of sleepiness and fatigue among upper airway resistance syndrome (UARS) patients are correlated with levels of somatic arousal (SA; reflecting the sympathetic nervous system component of the stress response). We also tested the correlations of post-treatment change in these three parameters, and we extended the investigation to obstructive sleep apnea/hypopnea (OSA/H) patients.

Methods

From 5 years of patient data, we obtained scores on the body sensation questionnaire (BSQ), measuring the level of SA, the fatigue severity scale (FSS), and Epworth sleepiness scale (ESS) for 152 consecutive UARS patients and 150 consecutive OSA/H patients. For each group, we correlated the FSS and ESS scores with the BSQ scores. Among the 45 UARS patients and 49 OSA/H patients treated with nasal CPAP who provided post-treatment data, we correlated change in FSS and ESS scores with change in BSQ scores.

Results

Scores on the BSQ, FSS, and ESS for UARS patients and OSA/H patients were comparable. In both UARS and OSA/H patients, both the FSS and ESS scores were positively correlated with the BSQ score. Nasal CPAP use decreased all three questionnaire scores in both patient groups. In the pooled data, changes in FSS were significantly correlated with changes in BSQ.

Conclusions

Our findings confirm our preliminary observations that sleepiness and fatigue among UARS patients are correlated with their level of SA and suggest that the same is true for OSA/H patients. The decrease of SA following treatment suggests that SDB is a cause of SA among patients with UARS and OSA/H.

     

Accuracy of respiratory inductive plethysmography for the diagnosis of upper airway resistance syndrome.

OBJECTIVE: To determine the sensitivity and specificity of quantitative respiratory inductive plethysmography (RIP) compared with the "gold standard," nocturnal esophageal pressure (Pes) measurement, in the diagnosis of upper airway resistance syndrome (UARS) in adults. METHODS: Fourteen consecutive patients without obstructive sleep apnea and suspected of having UARS underwent simultaneous measurement of Pes with a catheter and standard nocturnal polysomnography along with RIP. UARS events (RERAs, respiratory effort-related arousals) were identified by observing crescendo changes in Pes with a Pes nadir < or = -12 cm H2O, followed by an arousal or microarousal. UARS was defined as > or = 10 RERAs per hour. For each patient, the ratio of peak inspiratory flow to mean inspiratory flow (PIFMF) measured by RIP was performed during quiet wakefulness and with 40 randomly selected breaths in the supine position for two conditions: stage 2 sleep, immediately prior to arousals in any sleep stage. The mean PIFMF (wake-sleep) was calculated for each condition. RESULTS: The sensitivities and specificities, respectively, of RIP to distinguish UARS patients from non-UARS patients are from stage 2 sleep (67%, 80%), immediately prior to arousals (100%, 100%). For breaths occurring immediately prior to arousals, the mean PIFMF (wake-sleep) is > or = 0.13 for UARS patients and < 0.13 for non-UARS patients. CONCLUSION: The PIFMF measured by RIP allows for the most accurate identification of UARS patients when breaths are selected for analysis immediately prior to arousals.     

Daytime polysomnography for early diagnosis and treatment of patients with suspected sleep-disordered breathing

Excessive daytime sleepiness (EDS) is a common complaint among patients with sleep-disordered breathing (SDB). Population-based studies on traffic and industrial accidents suggest a relationship between EDS and life-threatening events, and adults with EDS have cognitive and memory problems. Nocturnal polysomnography (nPSG) is essential for diagnosing SDB but it is time and energy consuming. We examined the usefulness of daytime polysomnography (dPSG) for the early diagnosis and treatment of patients with suspected SDB. We studied 108 consecutive patients aged 51.9 +/- 13.5 years (mean+/-SD). All patients underwent dPSG and nPSG. The number of apnea/hypopnea episodes per hour (apnea/hypopnea index: AHI) and the number of 3% desaturation episodes per hour (desaturation index: DSI) were calculated. All patients were classified into two groups. The REM group consisted of subjects who had an AHI < or = 25/h, AHI(REM)/AHI(NREM) > 2, and AHI(NREM) < 15/h. Those who did not satisfy these criteria were placed in the NREM group. Continuous positive airway pressure (CPAP) titration was performed for patients whose AHI was > or =20/h on dPSG. Using the international classification of sleep disorders, 96 patients were diagnosed as obstructive sleep apnea [including five upper airway resistance syndrome (UARS) patients], six patients were snoring, four had idiopathic hypersomnia due to a medical condition, and two had circadian rhythm sleep disorders. The sensitivity of dPSG for AHI was 81.0%, specificity was 100%, and accuracy was 83.5%. The sensitivity and accuracy of dPSG for AHI in the REM group were considerably lower than in the NREM group. There was no significant difference for optimal CPAP between dPSG and nPSG. In the five patients with UARS, their AHI, DSI, and arousal index on dPSG were 0.92 +/- 1.2/h, 2.9 +/- 3.4/h, and 29.3 +/- 3.5/h, respectively, and their AHI and DSI on nPSG were 3.2 +/- 2.5/h and 2.8 +/- 2.4/h, respectively. However, their respiratory effort-related arousals were 37.9 +/- 7.4/h, and their arousal index was 33.2 +/- 6.3/h. The five patients with UARS were also treated with CPAP, and their daytime sleepiness was improved. Although dPSG has limitations, these results indicate that dPSG recording is clinically useful for the diagnosis of and determination of types of treatment in patients with suspected SDB.     

The upper airway resistance syndrome

Obstructive sleep apnea syndrome has been recognized as a major public health problem. Both its cardiovascular and metabolic comorbidities and symptoms motivate for an accurate diagnosis and appropriate treatment. The main stimulus associated with obstructive sleep apnea (OSA) and explaining deleterious consequences is intermittent hypoxia. The upper airway resistance syndrome (UARS) has been described based on the hypothesis that snoring and repetitive occurrence of respiratory effort-related arousals (RERAs) but not oxygen desaturation might produce a significant disease with symptoms, altered quality of life and cardiovascular morbidity. Diurnal sleepiness remains the main diagnostic criteria, which is often confounded with tiredness in women. UARS patients may also report insomnia and symptoms that closely resemble those of the functional somatic syndromes. Currently, the International Classification of Sleep Disorders does not individualize UARS as a specific entity and reports UARS patients as a subgroup of OSA. However, RERAs are described as unambiguous abnormal respiratory events occurring during sleep and requiring a specific scoring. In this review, the authors attempt to describe the specific characteristics of UARS that are relevant for both clinicians and researchers.     

Sleep-disordered breathing in patients with the Brugada syndrome

We investigated breathing patterns and the occurrence of arrhythmias and ST-segment changes during sleep in patients with Brugada syndrome. Patients with Brugada syndrome are more likely to die from ventricular arrhythmias during sleep. ST-segment changes have been correlated with risk of sudden cardiac death. Whether sleep disturbances may contribute to arrhythmogenesis is unknown. Patients with Brugada syndrome underwent overnight polysomnography with simultaneous 12-lead electrocardiographic recording. A control group matched by age, gender, and body mass index (BMI) also underwent polysomnography. Twenty patients were included (50 ± 15 years old, 75% men). Despite their normal BMI (24.7 ± 2.7 kg/m(2)), 45% had sleep-disordered breathing (SDB), with a mean apnea-hypopnea index of 17.2 ± 14 events/hour. In patients with a high risk of arrhythmias, 5 (63%) had SDB. In the control group, 27% had SDB. Atrial or ventricular arrhythmias were not observed. Spontaneous ST-segment changes occurred in 2 patients over 45 different time points. Most ST-segment changes were observed during rapid eye movement sleep (31%) or within 1 minute of arousals (44%). Regarding respiratory events, 25 (56%) of ST-segment changes were related to occurrence of apnea or hypopnea. In conclusion, patients with Brugada syndrome have a high prevalence of SDB even in the setting of normal BMI. The higher incidence of nocturnal death in patients with Brugada syndrome may be conceivably related to co-morbid SDB. Moreover, autonomic instability encountered in rapid eye movement sleep and arousals could potentiate the risk of arrhythmias.     

Variation in severity and type of sleep-disordered breathing throughout 4 nights in patients with heart failure

BACKGROUND: Over 50% of patients with chronic heart failure (CHF) have sleep-disordered breathing (SDB). Any variation in the type of SDB in CHF will have implications for patient management. Currently there is good evidence for treatment of obstructive sleep apnea (OSA) in CHF with continuous positive airway pressure; however, for central sleep apnea (CSA) the treatment is less clear. AIMS: The aim of this study was to investigate the variation in the severity and type of SDB (OSA vs. CSA) throughout 4 consecutive nights in CHF patients with SDB. METHODS: Nineteen male CHF patients (mean+/-sd: age 61+/-9 years; left ventricular ejection fraction: 34+/-10% and percent predicted peak VO2: 67+/-19%) underwent cardiorespiratory monitoring in their own home throughout 4 consecutive nights. RESULTS: There was minimal variation in apnea-hypopnea index (AHI) throughout 4 nights in CHF patients with SDB [intraclass correlation coefficient (95% confidence interval (CI)): 0.97 (95% CI 0.76 and 0.97)]. Eight patients [42% (95% CI 20% and 64%)] demonstrated a shift in the type of their SDB, from CSA to OSA or vice versa; these patients had significantly smaller neck circumference (group mean+/-sd) 42+/-2 vs. 44+/-2 cm; p=0.04), and had significant variation in the central AHI [intraclass correlation coefficient: 0.51 (95% CI 0.16 and 0.85)]. CONCLUSIONS: A single night of cardiorespiratory monitoring is representative of moderate-to-severe SDB in patients with CHF. However, a high proportion of patients shift their type of SDB over 4 nights. These findings may have implications for the management of SDB in CHF.     

Sleep-related breathing in children with mucopolysaccharidosis

Summary   Background: The mucopolysaccharidoses (MPSs), a group of genetic lysosomal storage disorders, are associated with significant morbidity. Secondarily to specific associated anatomical abnormalities, MPS is associated with sleep disordered breathing (SDB), specifically obstructive sleep apnoea (OSA) that may confer additional morbidity. Few studies have examined SDB in children with MPS using full polysomnography (PSG) and thus the exact prevalence and severity of SDB is unknown. Further, successful treatments for SDB in this population have not been explored. Objectives: This study evaluated both SDB and the efficacy of treatments offered to children with MPS using PSG data. Patients and methods: A retrospective chart review was conducted on all children with MPS and a history of suspected OSA who were referred to the Hospital for Sick Children, Toronto. Both baseline and follow up treatment PSG data were analysed. PSG data recorded included obstructive apnoea-hypopnoea index (OAHI) and central apnoea index (CAI). Results: Fourteen patients (10 male) underwent a baseline PSG. Three of 14 children on ERT were excluded from the main analyses. The median (range) baseline parameters of the population (n = 11) were recorded. The age was 5.2 years (0.8–17.8) and the body mass index (BMI) was 19.9 (13.7–22.2). The OAHI was 6.6 (0.0–54.8); the CAI was 0.6 (0.0–2.6). Seven of 11 (64%) had evidence for OSA and 3/7 children were classified as having severe OSA (OAHI > 10). Of these, 5/7 children underwent treatment for OSA with 3/5 children showing a significant reduction in their OAHI. Further, the 2 patients on ERT therapy with OSA were also both successfully treated. Conclusions: Children with MPS have a high prevalence of significant OSA and thus should be carefully screened for OSA using full polysomnography and treated accordingly. Competing interests: None declared     

Assessment of inspiratory flow limitation in children with sleep-disordered breathing by a nasal cannula pressure transducer system

A nasal cannula pressure transducer system identifies inspiratory flow limitation and increased upper airway resistance in adults with sleep-disordered breathing (SDB). The purpose of this study was to evaluate whether nasal cannula pressure (NCP) detects apneas and hypopneas as well as additional flow-limited events associated with increased airway resistance in children. We studied NCP in 47 patients (ages 2-14 years) referred for SDB to a university-based sleep disorders program during nocturnal polysomnography (NPSG). During NPSG, airflow was assessed simultaneously by thermistor and NCP. There was a high correlation between apneas assessed by thermistor (T) and NCP (r = 0.90, P < 0.0001), and for hypopneas using these two methods (r = 0.94, P = 0.0001). Respiratory driving pressure was indirectly measured with an esophageal pressure catheter. Flow-limited (flattened) NCP waves were associated with significantly higher driving pressure, indicating elevated upper airway resistance, compared to nonflow-limited (rounded) waves during nonrapid eye movement (NREM) (P = 0.05) and rapid eye movement (REM) (P = 0.01) sleep. Patients were classified as either having obstructive sleep apnea syndrome (OSAS) or primary snoring, based on standard NPSG criteria. NCP identified additional respiratory events with a flattened contour (FC) not detected by thermistor. NCP is a noninvasive device that identifies obstructive apneas and hypopneas as well as additional respiratory events associated with flow limitation in children.     

Sleep-disordered breathing in patients with symptomatic heart failure: a contemporary study of prevalence in and characteristics of 700 patients

AIM: Evaluation of the prevalence and nature of sleep-disordered breathing (SDB) in patients with symptomatic chronic heart failure (CHF) receiving therapy according to current guidelines. METHODS AND RESULTS: We prospectively screened 700 patients with CHF (NYHA class> or =II, LV-EF< or =40%) for SDB using cardiorespiratory polygraphy (Embletta). Furthermore, echocardiography, cardiopulmonary exercise and 6-min walk testing were performed. Medication included ACE-inhibitors and/or AT1-receptor blockers in at least 94%, diuretics in 87%, beta-blockers in 85%, digitalis in 61% and spironolactone in 62% of patients. SDB was present in 76% of patients (40% central (CSA), 36% obstructive sleep apnoea (OSA)). CSA patients were more symptomatic (NYHA class 2.9+/-0.5 vs. no SDB 2.57+/-0.5 or OSA 2.57+/-0.5; p<0.05) and had a lower LV-EF (27.4+/-6.6% vs. 29.3+/-2.6%, p<0.05) than OSA patients. Oxygen uptake (VO(2)) was lowest in CSA patients: predicted peak VO(2) 57+/-16% vs. 64+/-18% in OSA and 63+/-17% in no SDB, p<0.05. 6-min walking distances were 331+/-111 m in CSA, 373+/-108 m in OSA and 377+/-118 m in no SDB (p<0.05). CONCLUSIONS: This study confirms the high prevalence of SDB, particularly CSA in CHF patients. CSA seems to be a marker of heart failure severity.     

A comparison of inspiratory airflow dynamics during sleep between upper airway resistance syndrome patients and healthy controls

Objectives

A test of the hypothesis that upper airway resistance syndrome (UARS) patients have an increased prevalence of inspiratory airflow limitation (IFL) during sleep compared to healthy controls.

Methods

We compared inspiratory airflow dynamics during sleep between 12 UARS patients (nine females and three males) and 12 healthy controls matched for age, gender and obesity with maximal age limited at 45 years. A standard clinical polysomnogram (airflow measured with a nasal/oral pressure catheter) was performed to assess the impact of SDB on the participants’ natural sleep. A second full-night polysomnogram with a pneumotachograph and a supraglottic pressure catheter to measure airflow and effort was performed to compare the maximal inspiratory airflow and effort and the percentage of flow-limited breaths during supine, continuous stage 2 sleep between groups.

Results

During clinical polysomnography, UARS participants did not differ significantly from controls in sleep architecture or fragmentation. We observed a small difference in apnea hypopnea index between UARS participants and controls (1.6?±?1.9 vs. 0.4?±?0.3, respectively; p?=?0.035). During supine, continuous stage 2 sleep, 64.2 % (35.8; mean (SD)) of UARS participants’ breaths were flow-limited compared with 34.0 % (39.3) of controls’ breaths (p?=?0.06). The groups did not differ in maximal inspiratory airflow or inspiratory effort.

Conclusions

Our findings indicate a less-than-robust difference in respiratory parameters during sleep between UARS patients and healthy controls and no difference in standard sleep parameters or sleep fragmentation. We consider a pathophysiology of UARS that incorporates these findings.     

Automated detection of sleep disordered breathing using a nasal pressure monitoring device

To assess the accuracy of a single channel portable monitoring device (RUSleeping™ RTS, Respironics, Murrysville, PA) that measures nasal pressure (a surrogate for airflow) to detect sleep disordered breathing (SDB). Twenty-five adult patients referred to a community sleep laboratory with suspected obstructive sleep apnea (OSA) participated in this investigation. The portable monitoring device was used in the sleep laboratory to acquire data concurrently with a standard multi-channel polysomnogram (PSG) to assess SDB. Respiratory events were scored manually on the PSG using standard criteria for clinical research to quantify an apnea–hypopnea index (AHI) based on events during sleep. The portable monitoring device automatically calculated an unedited respiratory event index (REI) based on recording time. These data were then compared using the Pearson product–moment correlation coefficient, Bland–Altman analysis, receiver operating characteristic (ROC) curves, and likelihood ratios. All 25 subjects completed the study. Mean age of subjects was 42.4 ± 12.9 years and mean body mass index was 31.0 ± 7.4 kg m⁻². There was good agreement between the REI and the AHI (R = 0.77, p < 0.001, mean difference 2.6 events per hour [2 SD: 39.8] using a Bland–Altman plot). The area under the ROC curve for detecting SDB (PSG AHI greater than or equal to five events per hour) with the REI was 0.94 (95% CI 0.84–1.0). For an REI >11.9 events per hour, the sensitivity was 0.89 (95% CI 0.65–0.99) and the specificity was 0.86 (95% CI 0.42–1.0) with a likelihood ratio of 6.2 for a positive test (LR+) and 0.13 for a negative test (LR−). Similar results were observed for detecting moderate–severe SDB (PSG AHI ≥ 15 events h⁻¹) using REI >15.2 events h⁻¹. In a population of subjects with suspected OSA, this portable monitoring device can automatically quantify an REI that compares well to the AHI scored manually on a concurrent PSG. Such a device may prove useful to assess SDB in high risk populations with self-administered testing in ambulatory settings such as the home. This study was performed at the Sleep Center of Greater Pittsburgh Sleep Laboratory.     

Sleep-disordered breathing in pregnancy: a review of the physiology and potential role for positional therapy

Background

Sleep disordered breathing (SDB) has been shown to be associated with negative clinical sequelae such as systemic hypertension and cardiovascular disease. It has been reported in the literature that approximately 53–56 % of patients with obstructive sleep apnea (OSA) have positional OSA, known as POSA.

Potential treatment for SDB in pregnancy

These findings have led to a resurgence of positional therapy as an effective treatment for select patients with SDB. Pregnant patients can also be diagnosed with SDB, the negative consequences of which not only pertain to the patient but to the unborn fetus as well. Despite this, however, SDB is under-diagnosed in pregnant patients and research looking at SDB in pregnant patients and potential therapies are scarce.

Conclusions

This article reviews the literature regarding the physiologic respiratory changes that occur during pregnancy, SDB in pregnancy, supine hypotensive syndrome (SHS), complications and current treatments for these events and potential roles for positional therapy in pregnant women whose problems may be specifically position dependent.     

Incidence of sleep-disordered breathing in patients with hypertrophic cardiomyopathy

The authors investigated the prevalence of sleep-disordered breathing (SDB) together with its clinical correlations in patients with hypertrophic cardiomyopathy (HCM). A total of 113 consecutive patients including 63 patients with HCM (40 men; mean age, 59.5±13.0 years; New York Heart Association class, 2.0±0.9) underwent cardiorespiratory polygraphy in addition to their clinical work-up including echocardiography. Patients with an apnea-hypopnea-index (AHI) ≥5/h were considered to have SDB. If thoracic and abdominal inspiration efforts were documented, SDB was considered to be obstructive sleep apnea (OSA), otherwise SDB was considered to be central sleep apnea (CSA). The age- and sex-matched control group of 50 patients had exclusion of coronary artery disease by angiography, and normal left ventricular (ejection fraction ≥55%) and valvular function. SDB was diagnosed in 52 patients (82.5% vs 72% in the control group; P =not significant) with a mean AHI of 23.0±17.8/h. Severity of SDB was higher in patients with HCM than in the control group (AHI 12.2±7.6/h; P =.003). OSA was documented in 39 patients (AHI 21.2±16.5/h) and CSA in 13 (AHI 28.4±20.9/h). The severity of SDB correlated with New York Heart Association functional class (η=0.9, η(2) =0.811) and with left ventricular end-diastolic (r=0.6, P <.01) and left atrial (r=0.4, P <.01) diameter. No correlations were found between SDB and other clinical or echocardiographic parameters. SDB is common in patients with hypertrophic cardiomyopathy, with a predominance of OSA and correlations with markers of left ventricular function.     

Silent upper airway resistance syndrome: prevalence in a mixed military population

STUDY OBJECTIVES: The upper airway resistance syndrome (UARS) is a recently described form of sleep-disordered breathing in which transient increases in upper airway resistance result in repetitive EEG arousals. UARS is not associated with apnea or diminished airflow, although snoring and excessive daytime somnolence (EDS) are common. This report describes a subset of patients with UARS diagnosed by polysomnography who do not manifest snoring, which we define as silent upper airway resistance syndrome (SUARS). DESIGN: A retrospective review of all polysomnographies performed at our sleep disorders center during 2000. SETTING: Sleep disorders center of a large, academic, military hospital. PATIENTS: Our center serves military personnel, military retirees, and their dependent families. INTERVENTIONS: Esophageal manometry during polysomnography was routinely performed on patients with hypersomnolence (Epworth sleepiness scale > 10) who demonstrated a total arousal index >or= 10/h and a respiratory disturbance index of < 5/h on prior polysomnography. UARS was definitely diagnosed in patients who demonstrated repetitive increased upper airway resistance (IUAR) associated with brief EEG arousals followed by normalization of esophageal pressure (Pes). IUAR was defined by a pattern of crescendo negative inspiratory Pes of 相似文献   

Sleep-disordered breathing and inappropriate defibrillator shocks in chronic heart failure

Purpose

Supraventricular tachyarrhythmias are a major cause of inappropriate defibrillator shocks. Sleep-disordered breathing (SDB) is a known risk factor for atrial fibrillation (AF). We hypothesized that Cheyne–Stokes respiration (CSA) and obstructive sleep apnea (OSA) have an impact on inappropriate defibrillator discharges in patients witch chronic heart failure (CHF) and cardiac resynchronization therapy with defibrillator (CRT-D).

Methods

In this study, 172 patients with CHF (LVEF ≤?45?%, NYHA-class ≥?2) and CRT-D underwent overnight polygraphy; 54 had no SDB (apnea–hypopnea index Results In all, 17 patients had inappropriate defibrillator shocks (9.9?%; eight oversensing due to lead fractures, five caused by atrial fibrillation, four because of sinus tachycardia). Mean event-free survival time was 33.5?±?1.2 months in the CSA group, 35.2?±?0.7 months in the OSA group, and 32.1?±?1.5 months in the no SDB group, respectively (CSA vs. no SDB p?=?0.63; OSA vs. no SDB p?=?0.31; CSA vs. OSA p?=?0.45). Stepwise Cox proportional hazard regression analysis revealed an independent association for age (per year: hazard ratio 0.90, 95?% confidence interval 0.85–0.96, p?Conclusions SDB was not associated with inappropriate defibrillator shocks. We assume this is due to the low incidenceand low proportion of inappropriate therapies in response to AF.