Respiratory Event-related Arousals Research Articles

Relationship between respiratory event-related arousal and increased pulse rate in patients with obstructive sleep apnea

Objective: To investigate the relationship between respiratory event-related arousal and increased pulse rate in patients with obstructive sleep apnea (OSA), and to evaluate whether elevated pulse rate can be used as a surrogate marker of arousal. Methods: A total of 80 patients [40 males and 40 females, age range (18-63 years), mean age (37±13) years] who attended the Sleep Center of the Department of Respiratory and Critical Care Medicine, Tianjin Medical University General Hospital for polysomnography (PSG) from January 2021 to August 2022 were enrolled. Stable PSG recordings of non-rapid eye movement (NREM) sleep to compare the mean pulse rate (PR), the lowest PR 10 seconds before the onset of arousal, and the highest PR within 10 seconds after the end of arousal associated with each respiratory event. At the same time, the correlation between the arousal index and the pulse rate increase index (PRRI), as well as ΔPR1 (highest PR-lowest PR) and ΔPR2 (highest PR-mean PR), respectively, with the duration of respiratory events, the duration of arousal, the magnitude of pulse oximetry (SpO2) decline, and the lowest SpO2 was analyzed. Among the 53 patients, 10 events without arousal and 10 events with arousal (matched for the magnitude of SpO2 decline) were selected for NREM in each of the 53 patients, and ΔPR before and after termination of respiratory events in the two groups was compared. In addition, 50 patients were simultaneously subjected to portable sleep monitoring (PM) and divided into non-severe OSA group (n=22) and severe OSA group (n=28), and ΔPR≥3 times,≥6 times,≥9 times, and≥12 times after respiratory events were used as surrogate markers of arousal, and ΔPR was scored manually and integrated into the respiratory event index (REI) of PM. Then, we compared the agreement between REI calculated from the four PR cut-off points and the apnea-hypopnea index (AHIPSG) calculated by the gold standard PSG. Results: ΔPR1 [(13±7)times/min] and ΔPR2 [(11±6)times/min] were significantly higher in patients with severe OSA than in patients with non-OSA,mild and moderate OSA. The arousal index was positively correlated with the four PRRIs (r 0.968, 0.886, 0.773, 0.687, P<0.001, respectively), and the highest PR [(77±12) times/min] within 10 s after the end of arousal was significantly higher than the lowest PR [(65±10) times/min, t=113.24, P<0.001] and the mean PR [(67±11) times/min, t=103.02, P<0.001]. ΔPR1 and ΔPR2 were moderately correlated with the decrease in SpO2 (r=0.490, 0.469, P<0.001). After matching the magnitude of SpO2 decline, the ΔPR[(9±6)/min] before and after the termination of respiratory events with arousal was significantly higher than that of respiratory events without arousal [(6±5)/min, t=7.72, P<0.001]. The differences between REI+PRRI3 and REI+PRRI6 and AHIPSG in the non-severe OSA group were not statistically significant (P values 0.055 and 0.442, respectively), and REI+PRRI6 and AHIPSG showed good agreement (the mean difference was 0.7 times/h, 95%CI 8.3-7.0 times/h). The four indicators of PM in the severe OSA group were statistically different from AHIPSG (all P<0.05), and the agreement was poor. Conclusions: Respiratory event-related arousal in OSA patients is independently associated with increased PR, and frequent arousal may lead to increased frequency of PR fluctuations, and elevated PR may be used as a surrogate marker of arousal, especially in patients with non-severe OSA, where elevated PR≥6 times significantly improves the diagnostic agreement between PM and PSG.

Toward Sleep Study Automation: Detection Evaluation of Respiratory-Related Events.

The diagnosis of sleep disordered breathing depends on the detection of respiratory-related events: apneas, hypopneas, snores, or respiratory event-related arousals from sleep studies. While a number of automatic detection methods have been proposed, their reproducibility has been an issue, in part due to the absence of a generally accepted protocol for evaluating their results. With sleep measurements this is usually treated as a classification problem and the accompanying issue of localization is not treated as similarly critical. To address these problems we present a detection evaluation protocol that is able to qualitatively assess the match between two annotations of respiratory-related events. This protocol relies on measuring the relative temporal overlap between two annotations in order to find an alignment that maximizes their F1-score at the sequence level. This protocol can be used in applications which require a precise estimate of the number of events, total event duration, and a joint estimate of event number and duration. We assess its application using a data set that contains over 10,000 manually annotated snore events from 9 subjects, and show that when using the American Academy of Sleep Medicine Manual standard, two sleep technologists can achieve an F1-score of 0.88 when identifying the presence of snore events. In addition, we drafted rules for marking snore boundaries and showed that one sleep technologist can achieve F1-score of 0.94 at the same tasks. Finally, we compared this protocol against the protocol that is used to evaluate sleep spindle detection and highlighted the differences.

The effect of laryngopharyngeal reflux on arousal in patients with obstructive sleep apnea

Background Laryngopharyngeal reflux (LPR) may be associated with the severity of obstructive sleep apnea (OSA). However, it is unknown whether LPR may be associated with arousal. Objective To clarify the effect of LPR on arousal in OSA. Methods This study included 120 OSA patients. The correlations between LPR scores and arousal index (ArI) were analyzed. Finally, to further clarify the effect of LPR on ArI, we analyzed the correlations between respiratory event-related arousal index (BERAI), leg-movement-related arousal index (LMRAI), snore-related arousal index (SRAI), spontaneous arousal index (SAI), and RSI score. Results Partial correlation analysis showed that the RSI score was positively correlated with ArI (p = .000), mainly correlated with BERAI and SAI (r = 0.422, p = .000; r = 0.212, p = .020). While controlling for apnea-hypopnea index (AHI), the RSI score was still positively correlated with ArI (p = .002), mainly correlated with BERAI and SAI (r = 0.252, p = .006; r = 0.200, p = .029). Conclusions and significance The effect of LPR symptoms on arousal in OSA exists. The more severe the LPR was, the more frequent the arousal in OSA patients was. Thereinto, respiratory event-related arousal and spontaneous arousal were the most obvious.

Automatic detection of respiratory events during sleep from Polysomnography data using Layered Hidden Markov Model

Objective. Sleep apnea is a serious respiratory disorder, which is associated with increased risk factors for cardiovascular disease. Many studies in recent years have been focused on automatic detection of sleep apnea from polysomnography (PSG) recordings, however, detection of subtle respiratory events named Respiratory Event Related Arousals (RERAs) that do not meet the criteria for apnea or hypopnea is still challenging. The objective of this study was to develop automatic detection of sleep apnea based on Hidden Markov Models (HMMs) which are probabilistic models with the ability to learn different dynamics of the real time-series such as clinical recordings. Approach. In this study, a hierarchy of HMMs named Layered HMM was presented to detect respiratory events from PSG recordings. The recordings of 210 PSGs from Massachusetts General Hospital’s database were used for this study. To develop detection algorithms, extracted feature signals from airflow, movements over the chest and abdomen, and oxygen saturation in blood (SaO2) were chosen as observations. The respiratory disturbance index (RDI) was estimated as the number of apneas, hypopneas, and RERAs per hour of sleep. Main results. The best F1 score of the event by event detection algorithm was between 0.22 ± 0.16 and 0.70 ± 0.08 for different groups of sleep apnea severity. There was a strong correlation between the estimated and the PSG-derived RDI (R 2 = 0.91, p < 0.0001). The best recall of RERA detection was achieved 0.45 ± 0.27. Significance. The results showed that the layered structure can improve the performance of the detection of respiratory events during sleep.

Incidence and predictors of comorbid insomnia in a sleep surgery clinic.

The objective was to determine the prevalence and predictors of comorbid insomnia in patients presenting for sleep surgery evaluation. The insomnia severity index (ISI) was utilized to evaluate patients' insomnia severity. A retrospective chart review was performed in patients presenting to an otolaryngology sleep surgery clinic; patients also completed a sleep history questionnaire. Patients were divided between those with and without clinically significant insomnia defined as ISI ≥ 15. A total of 119 patients were included in the study: 50 (42%) with an ISI ≥ 15 and 69 (58%) with an ISI < 15. Clinically significant insomnia was associated with respiratory disturbance index (P = .028) but not apnea-hypopnea index or SaO2 nadir (P > .05). Clinically significant insomnia was associated with frequency of wake ups (P = .008), time to fall back asleep (P = .049), history of continuous positive airway pressure device use (P = .012), Epworth Sleepiness Scale (P = .008), and Sino-nasal Outcome Test (SNOT-22) (P < .001). Patients reporting to a sleep surgery clinic are at an elevated risk for comorbid insomnia. The relationship between increased respiratory event-related arousals and nonsleep SNOT-22 scores to related sleep-maintenance insomnia supports the connection between insomnia, nasal obstruction, and continuous positive airway pressure intolerance. Sagheer SH, Scott ER, Ananth A, Boon M, Huntley C. Incidence and predictors of comorbid insomnia in a sleep surgery clinic. J Clin Sleep Med. 2021;17(11):2165-2169.

Functional Rhinoplasty and Uvuloplasty for Sleep-Disordered Breathing: A Step-by-Step Guide

Sleep-disordered breathing (SDB) represents a wide range of sleep-related breathing abnormalities including snoring, upper airway resistance syndrome, respiratory event–related arousal, obstructive sleep apnea (OSA), and obstructive sleep apnea syndrome.1 It has been established in the literature that SDB is associated with hypertension, stroke, hyperlipidemia, cardiac dysrhythmias, and excessive daytime sleepiness (EDS).1,2 The therapeutic resolution of these medical maladies has proven nonlinear and less than optimal by most treatment approaches for OSA.

Analysis of respiratory events in obstructive sleep apnea syndrome: Inter-relations and association to simple nocturnal features

ObjectiveThis study carefully evaluates the association of different respiration-related events to each other and to simple nocturnal features in obstructive sleep apnea–hypopnea syndrome (OSAS). The events include apneas, hypopneas, respiratory event-related arousals and snores. MethodsWe conducted a statistical study on 158 adults who underwent polysomnography between July 2012 and May 2014. To monitor relevance, along with linear statistical strategies like analysis of variance and bootstrapping a correlation coefficient standard error, the non-linear method of mutual information is also applied to illuminate vague results of linear techniques. ResultsBased on normalized mutual information weights (NMIW), indices of apnea are 1.3 times more relevant to AHI values than those of hypopnea. NMIW for the number of blood oxygen desaturation below 95% is considerable (0.531). The next relevant feature is “respiratory arousals index” with NMIW of 0.501. Snore indices (0.314), and BMI (0.203) take the next place. Based on NMIW values, snoring events are nearly one-third (29.9%) more dependent to hypopneas than RERAs. Conclusion1. The more sever the OSAS is, the more frequently the apneic events happen. 2. The association of snore with hypopnea/RERA revealed which is routinely ignored in regression-based OSAS modeling. 3. The statistical dependencies of oximetry features potentially can lead to home-based screening of OSAS. 4. Poor ESS-AHI relevance in the database under study indicates its disability for the OSA diagnosis compared to oximetry. 5. Based on poor RERA-snore/ESS relevance, detailed history of the symptoms plus polysomnography is suggested for accurate diagnosis of RERAs.

Can sleep microstructure improve diagnosis of OSAS? Integrative information from CAP parameters.

The scoring of American Academy of Sleep Medicine (AASM) arousal is mandatory for the definition of respiratory event-related arousal (RERA). However there are other EEG activation phenomena, such as A phases of cyclic alternating pattern (CAP) which are associated with respiratory events in non rapid eye movements (NREM) sleep. This study aims at quantifying the additional value of CAP for the definition of respiratory events and sleep alterations in OSAS. Analysis of polysomnographic recordings from nineteen OSAS patients was carried out. Scoring was focused on investigation of the cerebral response to flow limitation (FL) events. For this purpose we used both CAP rules and AASM arousal criteria. While no difference was demonstrated in the arousal index between mild and moderate-severe OSAS patients, CAP time showed a progressive enhancement from normal subjects (152.5±20.76) to mild (180.64±34.76) and moderate-severe (282.27±58.02) OSAS patients. In NREM sleep, only 41.1% of FL events met the criteria for the definition of RERA, while, 75.5% of FL events ended with a CAP A phase and most FL CAP (69.1%) terminated with a CAP phase A3 subtype. Our data indicate that the RERA scoring has a limited accuracy in the detection of FL events. In NREM sleep, CAP rules provided more information than AASM arousal for the definition of respiratory events and sleep alterations in OSAS.

Treatment of Obstructive Sleep Apnea Syndrome with Nasal Positive Airway Pressure Improves Golf Performance

Obstructive sleep apnea syndrome (OSAS) is associated with impairment of cognitive function, and improvement is often noted with treatment. Golf is a sport that requires a range of cognitive skills. We evaluated the impact of nasal positive airway pressure (PAP) therapy on the handicap index (HI) of golfers with OSAS. Golfers underwent a nocturnal polysomnogram (NPSG) to determine whether they had significant OSAS (respiratory disturbance index > 15). Twelve subjects with a positive NPSG were treated with PAP. HI, an Epworth Sleepiness Scale (ESS), and sleep questionnaire (SQ) were submitted upon study entry. After 20 rounds of golf on PAP treatment, the HI was recalculated, and the questionnaires were repeated. A matched control group composed of non-OSAS subjects was studied to assess the impact of the study construct on HI, ESS, and SQ. Statistical comparisons between pre- and post-PAP treatment were calculated. The control subjects demonstrated no significant change in HI, ESS, or SQ during this study, while the OSAS group demonstrated a significant drop in average HI (11.3%, p = 0.01), ESS, (p = 0.01), and SQ (p = 0.003). Among the more skilled golfers (defined as HI ≤ 12), the average HI dropped by an even greater degree (31.5%). Average utilization of PAP was 91.4% based on data card reporting. Treatment of OSAS with PAP enhanced performance in golfers with this condition. Treatment adherence was unusually high in this study. Non-medical performance improvement may be a strong motivator for selected subjects with OSAS to seek treatment and maximize adherence.

Correlates of Obstructive Apnea Duration

The duration of an obstructive apnea is dependent on gender, age, body position, and state. Termination of an obstructive respiratory event is attributed as the end result of an achieved specific negative inspiratory force, sufficient to result in cortical arousal. We used polysomnographic measures of tendency for arousal, hypothesizing that long apnea would be associated with a smaller tendency for arousal. From a clinical sleep laboratory sample, 140 subjects (82 men) with an obstructive apnea index>5 were selected. Subjects were split into those with long and short apnea by stratifying around median obstructive apnea duration. Those with long duration apnea were compared to short apnea for age, gender, apnea-hypopnea index (AHI), and a measure of tendency to arouse, respiratory event-related arousal to AHI ratio (RespArI:AHI). Obstructive apnea duration (mean±SD) was 20.7±5.6. Apnea duration trended toward being longer in men than women and was significantly longer in supine than nonsupine sleep (19.2±7.3 vs. 16.1±10; p=0.001) and REM than NREM sleep (24.3±9.0 vs. 19.7±5.1; p<0.001). Those with long compared with short apnea were significantly older; AHI was similar. RespArI:AHI was significantly higher for those with long compared with short apnea (0.58±0.24 and 0.43±0.19; p<0.0001). This difference was most apparent for women in whom RespArI:AHI for those with long and short apnea was 0.6±0.24 and 0.41±0.17 (p=0.001). For men, RespArI:AHI for those with long and short obstructive apnea was 0.56±0.24 and 0.44±0.2 (p=0.02). Long obstructive apnea duration occurs to a greater degree in older individuals, in supine, and REM sleep. Women more than men with long apnea had a greater tendency toward arousal.

Nocturnal Diaphoresis Secondary to Mild Obstructive Sleep Apnea in a Patient with a History of Two Malignancies

Numerous medical disorders, including obstructive sleep apnea, may cause nocturnal diaphoresis. Previous work has associated severe obstructive sleep apnea with nocturnal diaphoresis. This case report is of import as our patient with severe nocturnal diaphoresis manifested only mild sleep apnea, and, for years, his nocturnal diaphoresis was ascribed to other causes, i.e., first prostate cancer and then follicular B-cell lymphoma. Additionally, it was the nocturnal diaphoresis and not more common symptoms of obstructive sleep apnea, such as snoring, that led to the definitive diagnosis of his sleep apnea and then to treatment with a gratifying resolution of his onerous symptom.

The role of nocturnal polysomnography in assessing children with Chiari type I malformation

ObjectiveTo evaluate nocturnal polysomnogram findings in children with suspected symptomatic Chiari type I malformation, correlate them with clinical and magnetic resonance imaging data and to determine if this information has value in clinical decision making process. MethodsA retrospective review identified 24 children with type I Chiari malformation, presumed symptomatic who had undergone neurological assessment, cranial magnetic resonance imaging and nocturnal polysomnography. Perimedullary subarachnoid space effacement on the magnetic resonance studies and the magnitude of cerebellar tonsillar descent in relation to the McRae line were correlated with frequency of obstructive or central sleep apnea, number of cortical arousals and evidence of impaired vocal mobility on laryngoscopy. The Wilcoxon rank sum test was applied for continuous variables and the Fisher exact test for categorical variables. ResultsThe median age of the subjects was 6 years. The findings from 16/24 subjects with perimedullary subarachnoid space effacement (effaced group) were compared with those of 8/24 in the non-effaced group. The central apnea index [1.5 (IQR 1–3.5) versus 0.5 (IQR 0–1.5)] and cortical arousal index [12 (IQR 10–19) versus 8 (IQR 6.5–9)] were significantly higher in the effaced group than in the non-effaced group (p=0.0376 and 0.0036 respectively). Greater descent of tonsils as measured by distance from the McRae line to the tonsil tip was associated with significantly higher central apnea index, total arousal index and respiratory event related arousals. Measurements of clivus-canal angle, Klauss index and pB-C2 line did not correlate with abnormalities on polysomnography. ConclusionThe central apnea and arousal indices derived from the nocturnal polysomnogram correlate well with magnetic resonance imaging findings of subarachnoid space effacement and degree of tonsillar herniation. In children with Chiari type I malformation, the nocturnal polysomnogram findings provides important information that aids in the decision making process about proceeding with surgical decompression.

Turbinate Size and Sleep‐Related Breathing Disorders: Is There a Correlation?

Objective: The tail of the turbinates is a site of nasal obstruction that may be associated with sleep related breathing disorder (SBD). We describe a technique, the trans-oral nasopharyngoscopy (TON), to evaluate turbinate size and determine if an association exists between turbinate size and the various parameters measured in SBD. Method: Thirty-six patients with SBD completed an Epworth Sleepiness Scale (ESS) and a Quebec Sleep Questionnaire (QSQ). They underwent a nasal examination, allergy skin tests, full night polysomnography, and TON. Turbinate size was divided into two groups: I) turbinate obstructing 1/2. Results: Sixteen patients were grade I and 20 patients were grade II. Turbinate size at the choana did not show any statistical significant association with nasal congestion, allergies, ESS and QSQ scores. Among the PSG parameters analyzed, no association was found with the apnea-hypopnea index (AHI), but the size of the turbinate showed a positive correlation with respiratory event related arousals (RERA; P = .03). Total sleep time spent snoring showed a weak association with turbinate size. Conclusion: TON is a simple technique allowing the evaluation of the size of the turbinates. Turbinate size was associated with RERA and total sleep time spent snoring, but not with AHI.

Acetazolamide as an Adjunct to CPAP Treatment: A Case of Complex Sleep Apnea in a Patient on Long-Acting Opioid Therapy

A 41-year-old white woman on long-acting opioid therapy was diagnosed with moderate obstructive sleep apnea. On initiation of continuous positive airway pressure (CPAP), she manifested severe central apnea that was unresponsive to supplemental oxygen and interfered with CPAP titration. Acetazolamide, 250 mg, nightly at bedtime was initiated, and CPAP titration was repeated. On acetazolamide, optimal CPAP pressure was obtained with no manifestation of clinically significant central respiratory disturbance. This case suggests that acetazolamide may be an effective adjunct to positive airway pressure therapy in patients on long-acting opioids. A need exists for examination of acetazolamide in this capacity.

How much sleep apnea is too much? Authors' response

Our study [1] had two main purposes: first, to examine the occurrence of sleep-disordered breathing (SDB) in patients with chronic fatigue syndrome (CFS), and then to exclude patients with this confound in order to evaluate the structure of sleep in a group of patients with pure CFS to look for relations with the symptoms of fatigue and sleepiness. In order to do this, we had to define an upper limit for the occurrence of respiratory events that might explain the daytime symptoms. Martinez and Cassol are correct that the currently accepted cutpoint for abnormality proposed by the American Academy of Sleep Medicine (AASM) and Centers for Medicare & Medicaid Services (CMS) in the US is an apnea-hypopnea index (AHI) ≥ 5 per hour but less than 15 per hour – but only if symptoms such as EDS are present. However, the AHI is an insensitive measure of the severity of mild respiratory events (such as respiratory event-related arousals (RERAs)) as it requires either a 3 or 4% desaturation for the definition of hypopnea and this is frequently not present in respiratory events that cause arousal and may contribute to sleep disruption (RERA). For this reason, our cutpoint for SDB is based on a respiratory disturbance index (RDI) of 18 events per hour and not the AHI. The RDI includes RERAs along with the AHI, although we used a slightly different definition of hypopneas beginning with any event showing flow limitation rather than the current amplitude based entry criterion. The rationale for this is from an earlier paper by our group [2] that shows that the sensitivity and specificity for explaining EDS in a group composed of symptomatic but mild SDB and non-complaining controls were greater using the RDI criterion than the AHI criterion. Since that paper, it has become customary to use a cut-off of 15 events per hour for RDI in many applications. It is important to note that for RDI, using 5 events per hour will include essentially 80% of the normal population. Furthermore, as pointed out in our current paper [1], although we chose 18 events per hour as a cut-off to exclude three subjects (one with CFS and two normal subjects) when defining the final group for our sleep analysis who might have SDB, in fact the highest RDIs we saw in the non-SDB group were 10.4, 10.8, 10.1, and 9.5 events per hour; we feel these numbers are within a range seen in many normal subjects without EDS [2]. Thus, our cut-off of 18 is not effectively different from the more recently accepted number of 15 events per hour. And after excluding those subjects with high RDI values, there was no significant difference in the AHI of patients with only CFS, those with CFS and fibromyalgia and healthy controls (1.7 ± 1.6, 2.8 ± 2.6, and 2.2 ± 1.7, respectively). In fact, the above logic is not fundamentally different from the choice made by Martinez and Cassol in their own work [3-6], where they define SDB as present in fibromyalgia when the AHI <5 and when more than 10 RERAs per hour occurred (5 + 10 events = 15 per hour, similar to our cut-off of 18 per hour).

Obstructive Sleep Apnoea in Singapore: Polysomnography Data From a Tertiary Sleep Disorders Unit

Comprehensive sleep architecture and respiratory event data in local patients with suspected obstructive sleep apnoea (OSA) from overnight polysomnography (PSG), the gold standard for the evaluation of sleep-related breathing disorders, are not widely available. We present 1 year retrospective PSG data with the objective of describing PSG characteristics of patients evaluated for OSA in Singapore. PSG data of patients evaluated for OSA in 1 year (January through December 2005) in the Sleep Laboratory of a public tertiary hospital were retrospectively reviewed. Five hundred and eighty-four diagnostic PSG studies were performed in patients with symptoms suggestive of sleep-disordered breathing, including snoring, excessive daytime sleepiness, unrefreshing sleep, or recurrent unexplained awakenings. There were 449 male patients (76.9%) and 135 female patients (23.1%), with a mean age of 47.5 years (SD 12.7). Men were on average younger than women, 46.1 years versus 52.0 years (P <0.0005). The mean body mass index (BMI) was 27.9 (SD 6.7), with no significant difference between genders. An association was shown between apnoea-hypopnoea index (AHI) and BMI (Pearson correlation index r = 0.362). Men had overall significantly higher AHI (16.5 vs 9), shorter mean sleep onset latency (11 vs 16.5 minutes), more light sleep (65.5% vs 58.9%), less deep sleep (17.7% vs 23%), and more respiratory event related arousals per hour of sleep (11.6 vs 5.1) (P <0.0005). Severity was classified: AHI <5 ("Normal Overall AHI") (28.3%), AHI 5-15 ("Mild") (22.3%), AHI >15-30 ("Moderate") (18.3%), AHI >30 ("Severe") (31.2%). There was no significant age difference among the 4 groups. More severe OSA patients were significantly heavier, and had more light sleep, less deep sleep, less REM sleep, more respiratory event related arousals and lower levels of oxygen desaturation. OSA is predominant in middle-aged, overweight Singapore males and much less common in females who tend to be older. A majority of patients have moderate to severe OSA, which significantly disturbs normal sleep architecture. The relatively lower BMI compared to Caucasian OSA populations may be related to local craniofacial characteristics and/or higher percentage of body fat for BMI which has been described in Singaporeans.

Clinical Guidelines for the Use of Unattended Portable Monitors in the Diagnosis of Obstructive Sleep Apnea in Adult Patients

Clinical Guidelines for the Use of Unattended Portable Monitors in the Diagnosis of Obstructive Sleep Apnea in Adult Patients

Polysomnography in children scheduled for adenotonsillectomy

Several studies suggest that a reliable diagnosis of childhood sleep-disordered breathing (SDB) requires polysomnography (PSG). We compared clinical and PSG-based diagnoses in children scheduled for adenotonsillectomy (AT). Parent responses on a validated Pediatric Sleep Questionnaire were used to determine which symptoms could help identify children with clinical diagnoses of SDB but normal PSG. Thirty-four children aged 5.0 to 12.9 years and scheduled for AT to treat clinically diagnosed sleep-disordered breathing underwent laboratory-based PSG. Results were scored by 3 different criteria: 1) >1 obstructive apnea (2 breaths or longer) per hour of sleep; 2) >5 apneas or hypopneas per hour of sleep; or 3) >1 apnea, hypopnea, or respiratory event-related arousal per hour of sleep. Depending on the criterion used, the PSG documented SDB from a minimum of 18/34 subjects (53%, for criterion I) to as many as 30/34 subjects (88%, for criterion III). Among symptoms studied, absence of daytime mouth breathing and habitual snoring were most helpful in identification of children who had no evidence of SDB on PSG, by criterion I (Chi-square, P < 0.05). The absence of other common symptoms, such as "loud snoring" or "trouble breathing" at night, were not helpful. Children with clinical diagnoses of SDB may not consistently meet PSG criteria for this disorder. Questions about daytime mouth breathing and habitual snoring might help clinicians recognize children who would not have SDB on objective testing. Clinical identification of SDB confirmable on PSG could be improved. However, available outcome data do not yet clarify whether clinical or PSG criteria best identify children likely to suffer morbidity from SDB. C.

Pediatric sleep questionnaire scores predict postop improvement on PSG and behavior

Problem: Children scheduled for adenotonsillectomy frequently also have reversible disruptive behavior disorders (DBD). We examined whether preoperative scores on a sleep questionnaire could assist in predicting postoperative improvement of both polysomnographic variables and disruptive behavior disorders. Methods: Sixty children, (mean age, 8.3 years) were studied. Behavior assessment, a sleep questionnaire, and nocturnal polysomnography were completed shortly before and 1 year after adenotonsillectomy. Psychiatric evaluation was performed by a child psychiatrist. The Sleep Disordered Breathing Subscale Questionnaire included questions pertaining to symptoms of nocturnal obstruction and behavior items. Obstructive apneas and hypopneas were defined as 2 breaths or longer in duration. Rates of respiratory event-related arousals plus apneas and hypopneas defined the respiratory disturbance index (RDI). Results: Severity of SDB generally improved after adenotonsillectomy. DBDs were initially diagnosed in 25 (42%) of subjects and resolved in 12 (48%) of the diagnosed children postoperatively. There were no significant differences noted in the preoperative obstructive apnea index, apnea/hypopnea index, RDI or minimum oxygen saturation ( t tests, all P > 0.05) in children whose DBD resolved as compared to those whose DBD did not. There were, however, significant correlations between high scores on the preoperative SDB subscale and postoperative improvement in apnea/hypopnea index (Pearson correlation coefficient r = .28, P < 0.03), obstructive apnea index (r = 0.32, P < 0.02), and RDI (r = 0.28, P < 0.04). There was also a strong correlation seen between high preoperative questionnaire scores and resolution of DBD (r = 0.28, P < 0.02). Conclusion: Questionnaires about preoperative symptoms of SDB are predictive of improvement in polysomnographic abnormalities and DBD after adenotonsillectomy. The use of a Pediatric Sleep Questionnaire may be useful in determining which patients have behavioral disorders potentially treatable with surgical intervention. Significance: Questionnaires may provide a simple, inexpensive method of predicting clinical improvement after adenotonsillectomy in children with SDB and DBDs. Support: None reported.

The addition of frontal EEG leads improves detection of cortical arousal following obstructive respiratory events.

To examine the hypothesis that respiratory events in obstructive sleep apnea syndrome (OSAS) end in arousal not detected by conventional electroencephalographic (EEG) leads. Observational. The study was conducted at a major metropolitan sleep disorders center. 10 patients with untreated OSAS and 5 patients undergoing continuous positive airway pressure (CPAP) titration for OSAS. Standard clinical nocturnal polysomnography recordings were supplemented to include frontal EEG leads and airflow measured by nasal cannula pressure. In 10 untreated subjects, 1465 obstructive events (apneas, hypopneas, and flow limitation events), and in 5 subtherapeutic CPAP-titrated subjects, 459 total events were identified during non-rapid eye movement (REM) sleep only. American Academy of Sleep Medicine arousal criteria applied to central leads and to frontal leads allowed detection of an additional 24% respiratory event-related arousals by frontal leads than by conventional leads. Frontal arousal detection differed by event type: 16% of apneas, 21% of hypopneas, and 35% of flow limitation events. Autonomic correlate (increased heart rate) of both conventional and frontal arousals was similar (in a subgroup of 8 untreated patients, analyzing only flow limitation events). Tabulating frontal arousals separately for each frontal lead indicated that Fz as the sole frontal lead (added to conventional leads) increased detection of arousals by 19% over using only conventional leads (total of 92% of all obstructive respiratory events). The addition of a single frontal lead (Fz) yields additional respiratory-related arousal information that appears physiologically relevant. Future studies are needed to assess clinical relevance to the evaluation and treatment of sleep-disordered breathing.