Obstructive sleep apnea severity is associated with left ventricular mass independent of other cardiovascular risk factors in morbid obesity

OBJECTIVE

To evaluate the relation between obstructive sleep apnea (OSA) and left ventricular mass (LVM) in morbid obesity and the influence of gender, menopausal status, anthropometry, body composition, hypertension, and other cardiovascular risk factors in this relationship.

DESIGN

Cross-sectional descriptive study.

METHODS

Polysomnographic and echocardiographic studies were performed in a cohort of 242 patients (86 men, 100 premenopausal (PreM) and 56 postmenopausal (PostM) women), with grade II obesity and above (BMI: 43.7 ± 0.4 kg/m(2)) to investigate OSA and LVM respectively. Anthropometry, body composition, glucose tolerance, and blood pressure were also recorded.

RESULTS

OSA to different degrees was diagnosed in 76.2% of the patients (n: 166), its prevalence being 90.9% (n: 70) for men, and 76% (n: 38) and 63.8% (n: 58) for PostM and PreM women, respectively (p < 0.01). LVM excess was greatest for PostM women (90.2%), followed by men (81.9%) and PreM females (69.6%) (p < 0.01). LVM values increased in accordance to OSA severity (absence, 193.7 ± 6.9 g; mild, 192.6 ± 7.8 g; moderate, 240.5 ± 12.5 g; severe, 273.6 ± 14.6 g; p < 0.01). LVM magnitude correlated with the menopausal state, age, central adiposity, hypertension (HT), type 2 diabetes (DM), desaturation index (DI), and apnea-hypopnea index (AHI) (r = 0.41; p < 0.01). The relationship between LVM and AHI persisted in the multivariate analysis (β = 0.25; p < 0.05) after adjusting for age, gender, menopausal state, BMI, waist circumference, neck circumference, DI, fasting plasma glucose, DM, and HT. But if tobacco habits are included, the statistical difference disappears (β = 0.22; p = 0.06).

CONCLUSIONS

Morbid obesity is frequently associated with abnormal LVM, particularly in patients with OSA; this association is independent of HT, BMI, body composition, and other clinical factors, supporting a direct role of OSA on LVM in morbid obesity. This suggests that OSA and LVM might be taken as predictors of the cardiovascular risk in these patients.

Air leak during CPAP titration as a risk factor for central apnea

OBJECTIVES

Emergence of central sleep apnea has been described in the setting of continuous positive airway pressure (CPAP) initiation. The underlying mechanism is unclear; however, we postulate that air leak washing out anatomical dead space is a contributing factor.

DESIGN

Data were obtained from 310 patients with obstructive sleep apnea (OSA) who underwent either split-night or full-night CPAP titration during January to July of 2009. The majority (n = 245) underwent titration with a nasal mask. Average total leak and maximum total leak were measured at therapeutic CPAP level. Unintentional leak was calculated by subtracting manufacturer-defined intentional leak from maximum leak.

RESULTS

SUBJECTS WERE DIVIDED INTO TWO GROUPS: central apnea index (CAI) during titration < 5/hour and ≥ 5/hour. The groups were similar in terms of gender, age, BMI, and AHI. The CAI < 5 group had a median average leak of 45.5 L/min (IQR 20.8 L/min) versus 51.0 L/min (IQR 21.0 L/min) with CAI ≥ 5 (p = 0.056). Maximum leak was 59.5 L/min (IQR 27.0 L/min) with CAI < 5 and 75.0 L/min (IQR 27.8 L/min) with CAI ≥ 5 (p = 0.003). In the subset of subjects titrated using a nasal mask, median average leak was 42.0 L/min (IQR 17.0) in the CAI < 5 group and 50.0 L/min (IQR 16.8) in the CAI ≥ 5 group (p = 0.001). In the CAI < 5 group, median maximum leak was 57.0 L/min (IQR 23.0) versus 74.5 L/min (IQR 24.3) in the CAI ≥ 5 group (p < 0.001).

CONCLUSIONS

Leak during CPAP titration is associated with the development of acute central apnea; these data may have mechanistic and therapeutic implications for complex apnea.

COMMENTARY

A commentary on this article appears in this issue on page 1193.

National UK survey on the assessment and surgical management of suspected paediatric obstructive sleep apnoea syndrome

BACKGROUND

Controversy exists amongst ENT surgeons as to the best way to manage a non-syndromal and otherwise healthy child with suspected OSAS. In 2002, The American Association of Paediatricians stated that the gold standard is a full polysomnography (PSG) for all children with suspected OSA and the revised version in 2012 repeated that requirement but recognized that facilities are not always available. In 2009 a UK Multidisciplinary Consensus Statement disagreed and reserved a full PSG for younger and syndromal or complicated children. We undertook a survey of UK ENT surgeons before and after the UK Consensus Statement to identify common practice with regards to diagnosis and management of suspected paediatric obstructive sleep apnoea syndrome in the UK.

METHOD

A questionnaire based on the management of a typical clinical case was sent to 542 ENT consultants in 2005 and repeated in 2011.

RESULTS

Less than 2% used PSG in assessing the child presented in our case study in both surveys. About 70% of respondents indicated that they would proceed with management of the child with no form of sleep study at all and this clinical practice has not changed after UK Multidisciplinary Consensus Statement. The majority would treat a child with possible OSAS and no co-morbidities with adenotonsillectomy as an inpatient.

DISCUSSION

The availability of paediatric PSG is very limited and because of a lack of normative data, uncertainty about interpretation of abnormal results, the recognition that even moderate snoring without sleep apnoea has detrimental neuro-cognitive effects and the fact that adenotonsillectomy is a very effective treatment for paediatric OSA we felt that a pragmatic and safe approach was to treat selected patients as if they had a positive PSG with appropriate anaesthetic technique and post operative care and monitoring.

The high prevalence of obstructive sleep apnea among patients with bipolar disorders

INTRODUCTION

Sleep plays an important role in maintaining stability in bipolar disorders, and sleep disturbances can trigger mood episodes. Obstructive sleep apnea (OSA) is a common sleep disorder, yet the co-occurrence with bipolar disorder has not been methodically studied.

METHODS

This is a chart review of 482 consecutively seen patients with a bipolar disorder who underwent routine screening for OSA using a self-report sleep apnea questionnaire. Positive screens were referred for a sleep study.

RESULTS

A positive screen was found in 214 (44.4%) patients. Sleep studies were obtained on 114 patients, and 101, were diagnosed with OSA: point prevalence 21%.

DISCUSSION

The 21% prevalence fails to consider the false negative rate of the questionnaire, or the exclusion of patients who screened positive but failed to get a sleep study. Taking these into consideration it is estimated that the true prevalence of OSA in this study may be as high as 47.5%. The co-occurrence of OSA and bipolar disorders is markedly higher than previously thought. Of note, OSA may play a role in refractory bipolar, disorders, and carries significant mortality and morbidity that overlap, with the mortality and morbidity found with bipolar disorders.

LIMITATIONS

This was a retrospective study based on a self-report questionnaire. Polysomnographic confirmation was performed in only a subgroup of subjects.

CONCLUSIONS

The data suggest that unrecognized OSA may play a major role in the mortality and morbidity of bipolar disorders. All patients diagnosed with a bipolar disorder should be screened with an OSA questionnaire.

Chemoreception and asphyxia-induced arousal

Arousal protects against the adverse and potentially fatal effects of asphyxia during sleep. Asphyxia stimulates the carotid bodies and central chemoreceptors but the sequence of events leading to arousal is uncertain. In this review, the theoretical mechanisms leading to arousal from sleep are briefly summarized and the issue of whether central respiratory chemoreceptors (CRCs) or other types of CO2-responsive CNS neurons contribute to asphyxia-induced arousal is discussed. We focus on the role of the retrotrapezoid nucleus, the raphe and the locus coeruleus and emphasize the anatomical and neurophysiological evidence which suggests that these putative central chemoreceptors could contribute to arousal independently of their effects on breathing. Finally, we describe recent attempts to test the contribution of specific brainstem pathways to asphyxia-induced arousal using optogenetic and other tools and the possible contribution of a group of hypoxia-sensitive brainstem neurons (the C1 cells) to breathing and arousal.

Usefulness of snoreplasty in the treatment of simple snoring and mild obstructive sleep apnea/hypopnea syndrome - Preliminary report

THE AIM OF THE STUDY

To assess the effectiveness of sodium tetradecyl sulfate injection in the region of the soft palate to treat primary snoring and mild obstructive sleep apnea/hypopnea syndrome. Sodium tetradecyl sulfate, a preparation belonging to detergents, widely applied in Poland to treat varices by the method of compressive sclerotherapy was used in the study.

MATERIAL AND METHODS

The procedure of injected snoreplasty was performed in 21 patients, who were diagnosed with primary snoring or mild obstructive sleep apnea/hypopnea syndrome, based on subjective examination and polysomnography. Injected snoreplasty involves administration of sodium tetradecyl sulfate in the form of Fibrovein 1% or 3% preparation in the volume of 2ml, in the region of the soft palate. Injection of the preparation in the area of the soft palate induces the development of aseptic inflammation, which creates a scar which stiffens the soft palate and makes the tissues of this region less susceptible to vibrations.

RESULTS

The patients after injected snoreplasty reported a significant decrease in the intensity of snoring. The markedly shortened total time of snoring was found in check-up polysomnography performed six months after the procedure.

CONCLUSIONS

Injected snoreplasty is an effective procedure, especially, in patients manifesting persistent snoring. It is not indicated in the treatment of obstructive apneas during sleep. The advantages of this method are: minimal invasiveness, the low number of complications and slight pain.

Change of obstruction level during drug-induced sleep endoscopy according to sedation depth in obstructive sleep apnea

OBJECTIVES/HYPOTHESIS

We evaluated the change in upper airway collapse according to the depth of sedation during drug-induced sleep endoscopy (DISE), as well as characteristics possibly associated with that change.

STUDY DESIGN

Prospective, single center, observational study.

METHODS

Twenty-nine patients with upper airway collapse were twice evaluated using DISE according to the depth of sedation, as confirmed by the bispectral index (BIS), which is a measure of the level of consciousness. Changes in the site and degree of obstruction according to the change in sedation depth at the retropalatal and the retroglossal levels were evaluated. The possible contributing factors of this change were explored.

RESULTS

As DISE sedation deepened, the upper airway became narrower in 37% of patients at the retropalatal level and in 44.8% of patients at the retroglossal level. No clinical, polysomnographic, or cephalometric variables showed any association with the change in the degree of retroglossal airway narrowing, with the exception of mouth breathing during DISE.

CONCLUSIONS

The degree of upper airway narrowing can be aggravated according to the sedation depth. The monitoring of sedation depth during DISE is critical, especially in patients with mouth breathing.

Wireless Wearable Multisensory Suite and Real-Time Prediction of Obstructive Sleep Apnea Episodes

Obstructive sleep apnea (OSA) is a common sleep disorder found in 24% of adult men and 9% of adult women. Although continuous positive airway pressure (CPAP) has emerged as a standard therapy for OSA, a majority of patients are not tolerant to this treatment, largely because of the uncomfortable nasal air delivery during their sleep. Recent advances in wireless communication and advanced ("bigdata") preditive analytics technologies offer radically new point-of-care treatment approaches for OSA episodes with unprecedented comfort and afforadability. We introduce a Dirichlet process-based mixture Gaussian process (DPMG) model to predict the onset of sleep apnea episodes based on analyzing complex cardiorespiratory signals gathered from a custom-designed wireless wearable multisensory suite. Extensive testing with signals from the multisensory suite as well as PhysioNet's OSA database suggests that the accuracy of offline OSA classification is 88%, and accuracy for predicting an OSA episode 1-min ahead is 83% and 3-min ahead is 77%. Such accurate prediction of an impending OSA episode can be used to adaptively adjust CPAP airflow (toward improving the patient's adherence) or the torso posture (e.g., minor chin adjustments to maintain steady levels of the airflow).

Factors associated with the efficacy of mandibular advancing device treatment in adult OSA patients

The aim of this study was to evaluate the anthropometric, demographic, occlusal and cephalometric characteristics of a group of adult obstructive sleep apnea (OSA) patients treated with mandibular advancement devices (MADs) and to determine the factors associated with treatment efficacy. Twenty-three consecutive patients with mild to severe OSA (polysomnographically diagnosed [T0]) were recruited for this prospective study; they were treated with a Silensor(®) appliance, and a polysomnographic exam with the MAD in situ was performed 2 to 3 months later (T1) to evaluate MAD's efficacy. Based on apnea-hypopnea index (AHI) differences between the T0 and T1 values, patients were classified into two groups: completely recovered and not completely recovered patients. The differences in anthropometric, demographic, occlusal and cephalometric parameters between the two groups were analyzed, and significant parameters verified. The sample showed these prevalent characteristics: deep bite, crossbite, tooth wear, dental and skeletal Class II, mesofacial mandibular vertical growth pattern, low position of the hyoid bone, longer soft palate length. The transverse diameters of upper maxilla had the greatest impact on T0 AHI. The factors associated with MAD efficacy were: age under 55 years, distance between the hyoid bone and the mandibular plane (H-MP) less than 20 mm, divergence of mandibular vertical growth pattern (SN^MP) less than 29°.

Endothelial dysfunction and hypertension in obstructive sleep apnea - Is it due to intermittent hypoxia?

BACKGROUND

Obstructive sleep apnea (OSA) is a prevalent disorder causing hypertension. Endothelial dysfunction appears to underlie development of hypertension. It is not known whether hypoxia during sleep is necessarily the prerequisite process for endothelial dysfunction and hypertension in OSA. We therefore examined the relationship between endothelial-dependent vasodilatory capacity, hypoxia and circulating angiogenesis inhibitors in OSA.

METHODS AND RESULTS

We studies 95 subjects with and without OSA and hypertension. Endothelial-dependent vasodilation was assessed using brachial artery flow-mediated vasodilation method (FMD). Plasma angiogenesis inhibitors, endoglin (sEng) and fms-like tyrosine kinase-1 (sFlt-1), were measured using ELISA. The apnea-hypopnea indexes were 41 ± 5 and 48 ± 4 events/hr in normotensive OSA (N-OSA) and hypertensive OSA (H-OSA), respectively, indicating severe OSA. The sleep time spent with SaO2 < 90% (T < 90%) were 34 ± 8 and 40 ± 9 min, respectively. FMD was markedly impaired in H-OSA (8.0% ± 0.5) compared to N-OSA (13.5% ± 0.5, P < 0.0001), H-non-OSA (10.5% ± 0.8, P < 0.01), and N-non-OSA (16.1% ± 1.0, P < 0.0001). There was no correlation between T < 90% and FMD. Both OSA groups had elevated levels of sFlt-1 (62.4 ± 5.9 and 63.9 ± 4.7 pg/ml) compared to N-non-OSA (32.1 ± 6.5, P = 0.0008 and P = 0.0004, respectively) and H-non-OSA (41.2 ± 7.0, P < 0.05 and P = 0.03, respectively). In contrast, sEng was only elevated in H-OSA (4.20 ± 0.17 ng/ml) compared with N-OSA (3.64 ± 0.14, P = 0.01) and N-non-OSA (3.48 ± 0.20, P = 0.01). There was a modest but statistically significant inverse correlation between sEng and FMD in only H-OSA group (r = -0.38, P < 0.05).

CONCLUSION

These data show that patients with OSA and hypertension have marked impairment of FMD, independent of hypoxia exposure, which is associated with increased sEng.

The impact of spinal cord injury on breathing during sleep

The prevalence of sleep disordered breathing (SDB) following spinal cord injury (SCI) is considerably greater than in the general population. While the literature on this topic is still relatively small, and in some cases contradictory, a few general conclusions can be drawn. First, while both central and obstructive sleep apnea (OSA) has been reported after SCI, OSA appears to be more common. Second, SDB after SCI likely reflects a complex interplay between multiple factors including body mass, lung volume, autonomic function, sleep position, and respiratory neuroplasticity. It is not yet possible to pinpoint a "primary factor" which will predispose an individual with SCI to SDB, and the underlying mechanisms may change during progression from acute to chronic injury. Given the prevalence and potential health implications of SDB in the SCI population, we suggest that additional studies aimed at defining the underlying mechanisms are warranted.

Impaired blood pressure control in children with obstructive sleep apnea

BACKGROUND

Obstructive sleep apnea (OSA) in adults has been associated with hypertension, low baroreflex sensitivity (BRS), a delayed heart rate response to changing blood pressure (heart period delay [HPD]), and increased blood pressure variability (BPV). Poor BRS may contribute to hypertension by impairing the control of blood pressure (BP), with increased BPV and HPD. Although children with OSA have elevated BP, there are scant data on BRS, BPV, or HPD in this group.

METHODS

105 children ages 7-12 years referred for assessment of OSA and 36 nonsnoring controls were studied. Overnight polysomnography (PSG) was performed with continuous BP monitoring. Subjects were assigned to groups according to their obstructive apnea-hypopnea index (OAHI): primary snoring (PS) (OAHI ≤1event/h), mild OSA (OAHI>1- ≤5events/h) and moderate/severe (MS) OSA (OAHI>5events/h). BRS and HPD were calculated using cross spectral analysis and BPV using power spectral analysis.

RESULTS

Subjects with OSA had significantly lower BRS (p<.05 for both) and a longer HPD (PS and MS OSA, p<.01; mild OSA, p<.05) response to spontaneous BP changes compared with controls. In all frequencies of BPV, the MS group had higher power compared with the control and PS groups (low frequency [LF], p<.05; high frequency [HF], p<.001).

CONCLUSIONS

Our study demonstrates reduced BRS, longer HPD, and increased BPV in subjects with OSA compared to controls. This finding suggests that children with OSA have altered baroreflex function. Longitudinal studies are required to ascertain if this dampening of the normal baroreflex response can be reversed with treatment.

Risk of new-onset atrial fibrillation in elderly patients with the overlap syndrome: a retrospective cohort study

OBJECTIVE

Co-existence of obstructive sleep apnea (OSA) and chronic obstructive pulmonary disease (COPD) is referred to as overlap syndrome. Overlap patients have greater degree of hypoxia and pulmonary hypertension than patients with OSA or COPD alone. Studies showed that elderly patients with OSA alone do not have increased risk of atrial fibrillation (AF) but it is not known if overlap patients have higher risk of AF. To determine whether elderly patients with overlap syndrome have an increased risk of AF.

METHODS

In this single center, community-based retrospective cohort analysis, data were collected on 2,873 patients > 65 years of age without AF, presenting in the year 2006. Patients were divided into OSA group (n = 60), COPD group (n = 416), overlap syndrome group (n = 28) and group with no OSA or COPD (n = 2369). The primary endpoint was incidence of new-onset AF over the following two years. Logistic regression was performed to adjust for heart failure (HF), coronary artery disease, hypertension (HTN), cerebrovascular disease, cardiac valve disorders, diabetes mellitus, hyperlipidemia, chronic kidney disease (CKD) and obesity.

RESULTS

The incidence of AF was 10% in COPD group, 6% in OSA group and 21% in overlap syndrome group (P < 0.05). After adjusting for age, sex, HF, CKD, and HTN, patients with overlap syndrome demonstrated a significant association with new-onset AF (OR = 3.66, P = 0.007). HF, CKD and HTN were also significantly associated with new-onset AF (P < 0.05).

CONCLUSION

Among elderly patients, the presence of overlap syndrome is associated with a marked increase in risk of new-onset AF as compared to the presence of OSA or COPD alone.

Sleep-related changes in autonomic control in obstructive sleep apnea: a model-based perspective

This paper reviews our current understanding of the long-term effects of obstructive sleep apnea (OSA) on cardiovascular autonomic function in humans, focusing directly on the knowledge derived from noninvasive measurements of heart rate, beat-to-beat blood pressure (BP), and respiration during wakefulness and sleep. While heart rate variability (HRV) as a means of autonomic assessment has become ubiquitous, there are serious limitations with the conventional time-domain and spectral methods of analysis. These shortcomings can be overcome with the application of a multivariate mathematical model that incorporates BP, respiration and other external factors as physiological sources of HRV. Using this approach, we have found that: (a) both respiratory-cardiac coupling and baroreflex dynamics are impaired in OSA; (b) continuous positive airway pressure therapy partially restores autonomic function; (c) baroreflex gain, which increases during sleep in normals, remains unchanged or decreases in OSA subjects; and (d) the autonomic changes that accompany transient arousal from NREM sleep in normals are largely absent in patients with OSA.

Effect of hypoxia on glucose metabolism in nondiabetic patients with obstructive sleep apnea syndrome

AIM

Obstructive sleep apnea syndrome (OSAS) may promote hyperglycemia and insulin resistance. Our aim is to investigate the effect of OSAS on the fasting plasma glucose, glycosylated hemoglobin (HbA1c), and C reactive protein (CRP) in nondiabetic patients.

MATERIAL AND METHODS

Blood parameters of consecutive 90 non diabetic patients whom polysomnografic evaluations were done in our sleep laboratory was evaluated. Among these 61 patients with normal fasting blood glucose were classified due to their apne-hipopnea index (AHI) as mild (n=16, 26.2%), moderate (n=18, 29.5%) and severe (n=27, 44.2%) OSAS. The fasting plasma glucose, HbA1c and CRP were measured.

RESULTS

Mean age of the patients was 47.7±11.2 years, 72% male. HbA1c, fasting glucose levels show positive correlation with BMI (r=.503, P=.00; r=.258, P=.045). No relation of HbA1c to apnea index nor AHI was detected while positive corelation of fasting glucose and CRP was detected (r=.262, P=.042; r=.258, P=.045). HbA1c, fasting glucose and CRP levels show negative correlation with minimum SpO2 levels (by order of r=-.302, P=.018; r=-.368, P=.004; r=-.365, P=.004). HbA1c, fasting glucose levels and CRP levels show positive correlation with mean desaturation index (time duration in which SpO2<90% by pulse oxymeter) (r=.263, P=.041; r=.311, P=.015; r=.283, P=.027).

CONCLUSIONS

Although no relation in between increased HbA1c or glucose levels and severity of OSAS was detected in nondiabetic OSAS patients, the correlation with the night hypoxia was detected. This could also show the effect of night time hypoxia on glucose metabolism in OSAS patients.

Clinical consequences of altered chemoreflex control

Control of ventilation dictates various breathing patterns. The respiratory control system consists of a central pattern generator and several feedback mechanisms that act to maintain ventilation at optimal levels. The concept of loop gain has been employed to describe its stability and variability. Synthesizing all interactions under a general model that could account for every behavior has been challenging. Recent insight into the importance of these feedback systems may unveil therapeutic strategies for common ventilatory disturbances. In this review we will address the major mechanisms that have been proposed as mediators of some of the breathing patterns in health and disease that have raised controversies and discussion on ventilatory control over the years.

Computerized cephalometric study of the pharyngeal airway space in patients submitted to orthognathic surgery

INTRODUCTION

Pharynx is a muscular organ with is sustained by craniofacial bones. It is divided into nasal, oral and hipopharynx, and can be considered as a tube that serves both respiratory and digestive systems. Its anatomical morphology permits that factors facilitate its obstruction, leading to the sleep apnea syndrome. One of the treatment consists of surgical mandibular advancement, increasing pharyngeal dimensions. The aim of this study was evaluate the cephalometric changes in the pharyngeal airway space after orthognathic surgery procedures for correction of mandibular prognathism.

MATERIALS AND METHODS

Pre and post-operative cephalometric analysis was performed on 19 patients submitted to mandibular setback by mandibular bilateral sagittal split osteotomy associated with maxillary advancement by Le Fort I osteotomy, using the Dolphin Imaging 10.0 software.

RESULTS

Results did not reveal statistically significant changes in the upper (nasopharyngeal), middle (oropharyngeal) and lower (hypopharyngeal) airway spaces, but showed increase in the nasal pharynx due the maxillary advancement and a lower position of the hyoid bone due the mandibular setback.

DISCUSSION

Maxillomandibular orthognathic surgery for correction of mandibular prognathism does not seem to statistically significantly change the pharyngeal airway space, but it increases the maxillary airway.

CONCLUSION

It seems to be important to consider the double jaw surgery in cases of mandibular prognathism, aiming prevention of a possible reduction of whole upper airway.

Circulating adhesion molecules in obstructive sleep apnea and cardiovascular disease

Over 20 years of evidence indicates a strong association between obstructive sleep apnea (OSA) and cardiovascular disease. Although inflammatory processes have been heavily implicated as an important link between the two, the mechanism for this has not been conclusively established. Atherosclerosis may be one of the mechanisms linking OSA to cardiovascular morbidity. This review addresses the role of circulating adhesion molecules in patients with OSA, and how these may be part of the link between cardiovascular disease and OSA. There is evidence for the role of adhesion molecules in cardiovascular disease risk. Some studies, albeit with small sample sizes, also show higher levels of adhesion molecules in patients with OSA compared to controls. There are also studies that show that levels of adhesion molecules diminish with continuous positive airway pressure therapy. Limitations of these studies include small sample sizes, cross-sectional sampling, and inconsistent control for confounding variables known to influence adhesion molecule levels. There are potential novel therapies to reduce circulating adhesion molecules in patients with OSA to diminish cardiovascular disease. Understanding the role of cell adhesion molecules generated in OSA will help elucidate one mechanistic link to cardiovascular disease in patients with OSA.

Obstructive sleep apnea after radial forearm free flap reconstruction of the oral tongue

OBJECTIVES/HYPOTHESIS

To determine whether radial forearm free flap reconstruction of the tongue after partial glossectomy is associated with obstructive sleep apnea.

STUDY DESIGN

Retrospective case series.

METHODS

Fifteen patients (5 men, 10 women) treated for tongue cancer in 2006-2010 by partial glossectomy and immediate radial forearm free flap reconstruction completed the Epworth Sleepiness Scale and underwent polysomnographic studies. Background, clinical, and pathologic data were collected from the medical files.

RESULTS

Mean ± SD age of the study group was 57 ± 19 years; body mass index, 24 ± 4; follow-up, 5.6 ± 2.8 years. Mean ± SD Epworth scale score was 8.18 ± 6.18 (normal, <8). Disordered sleep was documented in 11 patients, of whom 8 (53.3% of the cohort) had OSA (5 mild, 2 moderate, 1 severe). The OSA rate was significantly higher than reported in the general population (P = 0.001).

CONCLUSION

Patients after partial glossectomy and radial forearm free flap reconstruction appear to be at high risk of obstructive sleep apnea. Testing for OSA should be considered in these patients.

Mucopolysaccharidosis Type II and the G374sp Mutation

Mucopolysaccharidosis type II (MPS II), also known as Hunter syndrome, is a rare, X-linked disease caused by a deficiency of the lysosomal enzyme iduronate-2-sulfatase, which catalyses a step in the catabolism of glycosaminoglycans resulting in accumulation of heparan and dermatan sulfate in many organs and tissues. This accumulation favors the appearance of neurologic involvement, severe airway obstruction, skeletal deformities, and cardiomyopathy, especially mitral and aortic valve regurgitation. In severe cases, obstructive airway disease and cardiac failure due to valvular dysfunction are the most common causes of death within the second decade of life. However, in mild cases, intelligence remains normal, stature is almost normal and death usually occurs due to cardiac failure in the fourth decade of life. We report the presentation, diagnosis, management, and outcome of 2 siblings with MPS II and the G374sp mutation at the nucleotide c.1246 of the gene encoding for the iduronate-2-sulfatase.

A brief survey of patients' first impression after CPAP titration predicts future CPAP adherence: a pilot study

BACKGROUND

CPAP adherence patterns are often established very early in the course of therapy. Our objective was to quantify patients' perception of CPAP therapy using a 6-item questionnaire administered in the morning following CPAP titration. We hypothesized that questionnaire responses would independently predict CPAP adherence during the first 30 days of therapy.

METHODS

We retrospectively reviewed the CPAP perception questionnaires of 403 CPAP-naïve adults who underwent in-laboratory titration and who had daily CPAP adherence data available for the first 30 days of therapy. Responses to the CPAP perception questionnaire were analyzed for their association with mean CPAP adherence and with changes in daily CPAP adherence over 30 days.

RESULTS

Patients were aged 52 ± 14 years, 53% were women, 54% were African American, the mean body mass index (BMI) was 36.3 ± 9.1 kg/m(2), and most patients had moderate-severe OSA. Four of 6 items from the CPAP perception questionnaire- regarding difficulty tolerating CPAP, discomfort with CPAP pressure, likelihood of wearing CPAP, and perceived health benefit-were significantly correlated with mean 30-day CPAP adherence, and a composite score from these 4 questions was found to be internally consistent. Stepwise linear regression modeling demonstrated that 3 variables were significant and independent predictors of reduced mean CPAP adherence: worse score on the 4-item questionnaire, African American race, and non-sleep specialist ordering polysomnogram and CPAP therapy. Furthermore, a worse score on the 4-item CPAP perception questionnaire was consistently associated with decreased mean daily CPAP adherence over the first 30 days of therapy.

CONCLUSIONS

In this pilot study, responses to a 4-item CPAP perception questionnaire administered to patients immediately following CPAP titration independently predicted mean CPAP adherence during the first 30 days. Further prospective validation of this questionnaire in different patient populations is warranted.

Preliminary findings from our experience in anterior palatoplasty for the treatment of obstructive sleep apnea

OBJECTIVES

Obstructive sleep apnea (OSA) is a common disorder affecting at least 2% to 4% of adult population characterized by the collapse of the pharyngeal airway. It is well established that retropalatal region is the most common site of obstruction. Consequently, many surgical techniques have been introduced. The purpose of this study is to present our preliminary results in the anterior palatoplasty (AP) compared with results of uvulopalatal flap (UPF).

METHODS

Thirty-eight consecutive patients with mild-moderate OSA were prospectively enrolled into a randomised surgical protocol. Surgical success was measured primarily by satisfactory reduction in snoring, as reported by snoring assessment questionnaire (SQ) of sleep partners. Secondary outcomes measures included improvement in the Epworth Sleepiness Scale (ESS) scores, changes in the magnitude of pharyngeal collapse, and postoperative pain intensity.

RESULTS

The ESS after AP improved from a preoperative value 8.5±3.7 to a postoperative mean of 4.9±3.2 (P<0.001) after UPF improved from a preoperative value of 8.1±3.5 to 5.2±3.2 postoperatively (P<0.001). The results of satisfactory reduction in the volume of snoring and response at polysomnographic data were also similar in both procedures. We reported a statistically significant difference of the collapse noted at Müller manoeuvre that improved from 2.7±1.0 on average, to 1.1±0.9 (P<0.001) after AP and with a lesser extent, (from 2.8±1.1 on average to 1.8±1.1; P<0.05), after UPF. The mean duration of pain was 10.8 days for UPF patients and 7.1 days for AP patients. The mean pain score in the first 3 days, was 6.8 in UPF patients and 5.1 in AP patients.

CONCLUSION

The subjective and objective improvements evidenced may suggest how AP is far superior to other techniques aimed at creating a palatal fibrotic scar. In the light of these results we can suggest AP procedure as more practical and comfortable when compared to UPF.

Effect of an occlusal splint on sleep bruxism in children in a pilot study with a short-term follow up

The aim of the present study was to evaluate the effect of the use of an occlusal splint in children with bruxism in a pilot study with a short-term follow up. Seventeen children were recruited, only nine of whom formed the sample following the application of the inclusion criteria: presence of sleep bruxism for at least six months (based on parents' reports); presence of at least the first permanent molars; and no previous history of treatment involving an occlusal splint. The sample was submitted to a clinical exam. Other sleep problems were screened with the use of a sleep questionnaire filled out by parents before and after 90 days of occlusal splint usage. The children received a flat acrylic resin splint with full coverage of the occlusal surfaces to be worn in the maxilla. In children with erupting teeth, a space was created in the splint to allow normal eruption. After the 90-day period, the absence of sleep bruxism and sleep movements was noted in most of children. Moreover, snoring was reduced in nearly 50%, which raises a new issue to be investigated with regard to the pathophysiology of sleep bruxism. The use of an occlusal splint was effective in reducing the symptoms of sleep bruxism and other sleep problems. Further investigations should be carried out on the relationship between snoring and sleep bruxism in children.

CPAP effect on recurrent episodes in patients with sleep apnea and myocardial infarction

BACKGROUND

Obstructive sleep apnea (OSA) is linked to increased cardiovascular risk, but the association between OSA and myocardial infarction (MI) remains controversial. Our objectives were to compare the frequency of OSA in patients with acute MI and in a population-based sample of control subjects, and to evaluate the impact of CPAP on recurrent MI and coronary revascularization.

METHODS

Case-control study with a 6-year follow-up of the case cohort. 192 acute MI patients and 96 matched control subjects without coronary artery disease (CAD) (ratio 2:1). After overnight polysomnography, CPAP was recommended if apnea-hypopnea index (AHI) ≥ 5, and a mean daily use >3.5h/day was considered necessary to maintain the treatment. Lipids, fasting glucose, blood pressure, spirometry, comorbidity and current treatment were also registered. End-points were recurrent MI or need of revascularization.

RESULTS

OSA was an independent predictor of MI, with odds ratio 4.9 (95% confidence interval [CI] 2.9-8.3, p=0.017). 63 MI patients without OSA, 52 untreated patients with OSA and 71 OSA patients treated with CPAP were included in the follow-up study. After adjustment for confounding factors, treated OSA patients had a lower risk of recurrent MI (adjusted hazard ratio 0.16 [95%CI 0.03-0.76, p=0.021]) and revascularization (adjusted hazard ratio 0.15 [95%CI 0.03-0.79, p=0.025]) than untreated OSA patients, and similar to non-OSA patients.

CONCLUSION

Mild-severe OSA is an independent risk factor for MI. Risk of recurrent MI and revascularization was lower in OSA patients who tolerated CPAP.

Validation of the STOP-BANG Questionnaire among Patients Referred for Suspected Obstructive Sleep Apnea

BACKGROUND

The STOP-BANG is a simple obstructive sleep apnea (OSA) screening tool, part questionnaire (STOP) and part demographic or physical measures (BANG), developed for use in preoperative surgical clinics. This study assessed sensitivity and specificity of the instrument among patients referred to a sleep disorders laboratory, and also its performance characteristics when BANG physical measures are patient-reported rather than measured.

METHODS

Adults referred for diagnostic polysomnography completed the STOP questions and answered four yes/no questions (BANG self-reported) about their body mass index (weight and height), age, neck circumference, and gender, which were also assessed by laboratory technologists (BANG-measured).

RESULTS

Among N=219 subjects (mean age 46.3 ± 13.9 [s.d.] years; 98 [44.8%] males) the sensitivity of the STOP-BANG measured for an apnea/hypopnea index (AHI, events per hour of sleep) >5, >15, and >30 was 82, 93, and 97% respectively. Corresponding negative predictive values were 44, 87, and 96%. Specificities were comparatively low (48, 40, and 33%). The STOP-BANG measured and STOP-BANG self-reported scores showed essentially equivalent test characteristics against polysomnography.

CONCLUSIONS

The STOP-BANG appears to have limited utility in a referred, sleep laboratory setting. Negative results help to identify some individuals as unlikely to have moderate-to-severe apnea, and may thereby prove useful in identification of patients who would benefit more from laboratory studies than home studies. A STOP-BANG in which all information is self-reported may be as effective as the original version, and has potential to facilitate research or community screening where good negative predictive value is required for an effective screening tool.