Pathophysiology of upper airway obstruction during sleep

Pterygoid Hamulus: Morphological Analysis and Clinical Implications

INTRODUCTION

 The pterygoid hamulus (PH), as a small and curved projection of the sphenoid bone, occupies a unique position at the skull base. Given its functional relation with the surrounding anatomical structures, the study of this rather underrepresented structure in the literature assumes paramount importance.

MATERIALS AND METHODS

We examined a total of 87 pterygoid hamuli (50 right-sided and 37 left-sided) out of a sample of 114 dry skulls. We measured the length, width, and angle of each PH and the interpterygoid distance in skulls with both pterygoid hamuli intact, and we calculated the mean, maximum, and minimum values.

RESULTS

Our statistical analysis revealed the mean length (0.9 cm), width (0.3 cm), and angle (47.8°) of the PH, as well as the mean interpterygoid distance (3.31 cm). We recorded the longest-ever documented PH (1.64 cm). The obtained length values were higher than those provided by radiological studies. We also investigated possible associations between anatomy and pathological conditions related to the PH morphology, including pterygoid hamular elongation syndrome, hamular fracture, middle ear disorders, and obstructive sleep apnea syndrome.

CONCLUSION

Our study uses precise measurement techniques to detail the anatomy of the PH in dry skulls. This research can be a valuable resource for future studies, advancing our understanding of the PH's structure and its clinical significance.

International Consensus Statement on Obstructive Sleep Apnea

BACKGROUND

Evaluation and interpretation of the literature on obstructive sleep apnea (OSA) allows for consolidation and determination of the key factors important for clinical management of the adult OSA patient. Toward this goal, an international collaborative of multidisciplinary experts in sleep apnea evaluation and treatment have produced the International Consensus statement on Obstructive Sleep Apnea (ICS:OSA).

METHODS

Using previously defined methodology, focal topics in OSA were assigned as literature review (LR), evidence-based review (EBR), or evidence-based review with recommendations (EBR-R) formats. Each topic incorporated the available and relevant evidence which was summarized and graded on study quality. Each topic and section underwent iterative review and the ICS:OSA was created and reviewed by all authors for consensus.

RESULTS

The ICS:OSA addresses OSA syndrome definitions, pathophysiology, epidemiology, risk factors for disease, screening methods, diagnostic testing types, multiple treatment modalities, and effects of OSA treatment on multiple OSA-associated comorbidities. Specific focus on outcomes with positive airway pressure (PAP) and surgical treatments were evaluated.

CONCLUSION

This review of the literature consolidates the available knowledge and identifies the limitations of the current evidence on OSA. This effort aims to create a resource for OSA evidence-based practice and identify future research needs. Knowledge gaps and research opportunities include improving the metrics of OSA disease, determining the optimal OSA screening paradigms, developing strategies for PAP adherence and longitudinal care, enhancing selection of PAP alternatives and surgery, understanding health risk outcomes, and translating evidence into individualized approaches to therapy.

Management of Obstructive Sleep Apnea in Patients With Heart Failure

Sleep apnea is traditionally classified as obstructive sleep apnea (OSA), which occurs when the upper airway collapses due to the relaxation of oropharyngeal musculature, and central sleep apnea occurs when the brainstem cannot stimulate breathing. Most sleep apnea in patients with heart failure (HF) results from coexisting OSA and central sleep apnea (CSA), or complex sleep apnea syndrome. OSA and CSA are common in HF and can be involved in its progression by exposure to the heart to intermittent hypoxia, increased preload and afterload, activating sympathetic, and decreased vascular endothelial function. A majority of treatments have been investigated in patients with CSA and HF; however, less or short-term randomized trials demonstrated whether treating OSA in patients with HF could improve morbidity and mortality. OSA could directly influence the patient's recovery. This review will focus on past and present studies on the various therapies for OSA in patients with HF and summarize CSA treatment options for reasons of reference and completeness. More specifically, the treatment covered include surgical and non-surgical treatments and reported the positive and negative consequences for these treatment options, highlighting possible implications for clinical practice and future research directions.

Effects of Apnea, Obesity, and Statin Therapy on Proprotein Convertase Subtilisin/Kexin 9 Levels in Patients with Obstructive Sleep Apnea

OBJECTIVES

Obstructive sleep apnea (OSA) is a common condition closely related to obesity, insulin resistance, dyslipidemia, and cardiovascular disease. The aim of this study was to explore the possible relationship between OSA and proprotein convertase subtilisin/kexin type 9 (PCSK9).

METHODS

Full-night polysomnography was performed on 150 participants who were divided into three groups: controls, OSA patients on statin therapy, and OSA patients not on statin therapy. Biochemical markers, plasma low-density lipoprotein (LDL) and high-density lipoprotein (HDL) subclasses, and PCSK9 were determined.

RESULTS

PCSK9 was highest in OSA patients on statins compared to the control group and to OSA patients not on statins (p = 0.036 and p = 0.039, respectively), after adjustment for body mass index (BMI). LDL diameter was greater in OSA patients not on statins compared to OSA patients on statins (p = 0.032). PCSK9 was highest in the group of patients with all three risk factors (diagnosed OSA, statins, BMI ≥25 kg/m2) compared to groups with no, one, and two risk factors (p = 0.031, p = 0.001, and p = 0.029, respectively). Presence of OSA, statin therapy, and BMI ≥25 kg/m2 when combined were independently associated with higher levels of PCSK9 when adjusted for antihypertensive therapy, small dense LDL, and HDL 3c subclass (odds ratio = 2.849; interquartile range [1.026-7.912], p = 0.044).

CONCLUSION

Statin therapy was closely related to PCSK9. OSA along with obesity and statin use induces elevation of PCSK9.

Obstructive sleep apnoea/hypopnoea syndrome: relationship with obesity and management in obese patients

Obstructive sleep apnoea/hypopnoea syndrome (OSAHS) is a disease characterised by upper airway obstruction during sleep, quite frequent in the general population, even if underestimated. Snoring, sleep apnoea and diurnal hypersomnia are common in these patients. Central obesity plays a key role: it reduces the size and changes the conformation of the upper airways, besides preventing lung expansion, with consequent reduction of lung volumes. Furthermore, obese people are also resistant to leptin, which physiologically stimulates ventilation; as a result, this causes scarce awakening during apnoea. OSAHS diagnosis is based on the combination of clinical parameters, such as apnoea/hypopnoea index (AHI), medical history, physical examination and Mallampati score. The first objective reference method to identify OSAHS is polysomnography followed by sleep endoscopy. Therapy provides in the first instance reduction of body weight, followed by continuous positive airway pressure (CPAP), which still remains the treatment of choice in most patients, mandibular advancement devices (MAD) and finally otolaryngology or maxillofacial surgery. Among surgical techniques, central is barbed reposition pharyngoplasty (BRP), used in the field of multilevel surgery.

Efficacy of a Smart Antisnore Pillow in Patients with Obstructive Sleep Apnea Syndrome

Objective

Untreated obstructive sleep apnea syndrome (OSAS) increases the risk of cardiovascular, dementia, and motor vehicle accident events. However, continuous positive airway pressure (CPAP) which is the gold standard treatment is not acceptable for many patients with OSAS. Development of devices for the patients of nonadherence to CPAP is necessary.

Materials and Methods

We evaluated the effect of the smart antisnore pillow (SAP) in patients with OSAS in a prospective, noncontrolled, nonrandomized, pilot study. According to the apnea-hypopnea index (AHI), they were divided into two groups: mild-to-moderate OSAS group and severe OSAS group. Single-night polysomnography (PSG) with application of a SAP was performed. Thirty patients, 15 males and 15 females, 33–82 years old (mean age, 59.3 ± 12.9 years), completed the smart antisnore pillow therapy test. Among them, 23 patients had mild-to-moderate OSAS.

Results

The SAP significantly improved the snore number (p = 0.018), snore index (p = 0.013), oxygen denaturation index (p = 0.001), total AHI (p = 0.002), and supine AHI (p = 0.002) in the mild-to-moderate OSAS group, but there was no significant improvement in the severe OSAS group.

Conclusions

We concluded that the SAP is an effective positional therapy device for patients with OSAS of mild-to-moderate severity.

How might non nutritional sucking protect from sudden infant death syndrome

Epidemiology has identified an association between the use of pacifiers and protection from sudden infant death syndrome (SIDS). The use of pacifiers for SIDS prevention fails to gain adoption partly because there is no widely accepted physiologic mechanism to explain the epidemiologic association. Additionally, the scientific literature available on pacifier use focuses largely on the probable adverse effects. We hypothesize that pacifier use and all other forms of non-nutritional sucking (specifically digit sucking, also known as thumb sucking) is a life saving defense mechanism meant to splint open and stabilize the collapsible portion of the upper airway in infants.The main objective of this review article is to propose a mechanism to explain how pacifiers might help prevent SIDS. If the medical community accepts this mechanism, it can help promote pacifier use by the public and potentially reduce the incidence of SIDS.

Domiciliary use of transcutaneous electrical stimulation for patients with obstructive sleep apnoea: a conceptual framework for the TESLA home programme

Obstructive sleep apnoea (OSA) is a global health problem of increasing prevalence. Effective treatments are available with continuous positive airway pressure (CPAP) therapy and mandibular advancement devices (MAD). However, there is limited long-term adherence to therapy, as CPAP and MAD require permanent usage to avoid recurrence of the symptoms and adverse ill health. Alternative treatments would aid in the treatment cascade to manage OSA effectively whenever standard therapy has been trialled and failed. Hypoglossal nerve stimulation (HNS), an invasive approach to stimulate the pharyngeal dilator muscles of the upper airway during sleep, has been approved for the treatment of OSA by several healthcare systems in recent years. In parallel to the development of HNS, a non-invasive approach has been developed to deliver electrical stimulation. Transcutaneous electrical stimulation in obstructive sleep apnoea (TESLA) uses non-invasive electrical stimulation to increase neuromuscular tone of the upper airway dilator muscles of patients with OSA during sleep. Data from previous feasibility studies and randomised controlled trials have helped to identify a subgroup of patients who are "responders" to this treatment. However, further investigations are required to assess usability, functionality and task accomplishment of this novel treatment. Consideration of these factors in the study design of future clinical trials will strengthen research methodology and protocols, improve patient related outcome measures and assessments, to optimise this emerging therapeutical option. In this review, we will introduce a conceptual framework for the TESLA home programme highlighting qualitative aspects and outcomes.

Moderate OSAS and turbinate decongestion: surgical efficacy in improving the quality of life and compliance of CPAP using Epworth score and SNOT-20 score

SUMMARY

Drug-induced sleep endoscopy (DISE) is an important procedure in diagnostic pathway of patients affected by moderate OSAS. However, the Italian National Health System does not provide any compatible Diagnosis-related-group (DRG) code codification for DISE, which makes it impossible to obtain regional reimbursement. In order to overcome this problem, DISE is usually associated with other codified surgical procedures. The aim of our study is to assess the association of turbinate decongestion (TD) and DISE in order to combine in a single operating session diagnostic and therapeutic procedures. The objective of our work is to assess the role of nasal surgery on symptoms of moderate OSA. Recent studies have confirmed that isolated nasal surgery improves quality of life (QOL), but not the apnoea hypopnoea index (AHI) during polygraph registration. We enrolled 30 patients, aged between 29 and 64 years (mean 50.53 ± 9.20), 26 males and 4 females, with a mean BMI of 26.07 ± 2.81 kg/m², who were affected by moderate OSAS. All patients underwent otolaryngologycal pre-operative evaluation, home respiratory polygraph and subjective evaluation through Sino-Nasal-Outcome Test (SNOT-20) and Epworth Sleepiness Scale (ESS). During the same surgery session, they underwent DISE and TD. Patients were re-evaluated six months later using the same questionnaires. We observed a significant improvement (p #x003C; 0.05) in both the mean ESS index (6.03 ± 2.75 vs 4.16 ± 4.63) and total SNOT score (22.53 ± 12.16 vs 13.23 ± 10.82). Significant differences (p #x003C; 0.05) were also identified for partial SNOT questions 1-11 (9.1 ± 5.11 vs 6.13 ± 4.12) and 11-20 (13.36 ± 10.20 vs 7.13 ± 9.644). The results of the present study confirm that TD alone can improve sleepiness, QOL and nasal symptoms. Thus, in absence of a National Health System recognition for DISE, the association of this procedure with TD can be useful for diagnostic and therapeutic management of OSAS, improving CPAP compliance and adherence, reducing sleepiness, ameliorating nasal symptoms and therefore QOL.

Dynamic Upper Airway Imaging during Wakefulness in Obese Subjects with and without Sleep Apnea

RATIONALE

Obesity is a major risk factor for obstructive sleep apnea. Although greater dimensional changes in the upper airway during wake respiration have been noted in patients with apnea compared with control subjects, whether these differences remain in the presence of obesity is unknown.

OBJECTIVES

To evaluate upper airway anatomic characteristics and airway compliance (distensibility) in obese subjects with obstructive sleep apnea compared with obese control subjects.

METHODS

Dynamic magnetic resonance imaging was performed in 157 obese subjects with apnea and 46 obese control subjects during wakefulness in the midsagittal and three axial upper airway regions (retropalatal, retroglossal, epiglottal). Differences in measurements between subjects with apnea and control subjects, and correlations with apnea-hypopnea index among subjects with apnea, were examined.

MEASUREMENTS AND MAIN RESULTS

Measurements included airway areas and linear dimensions. Subject-specific coefficients of variation were calculated to examine variability in airway size. Controlling for covariates, the retropalatal area during respiration was significantly smaller in subjects with apnea than control subjects, based on the average (P = 0.003), maximum (P = 0.004), and minimum (P = 0.001) airway area. Airway narrowing was observed in anteroposterior and lateral dimensions (adjusted P < 0.05). Results were similar in an age, sex, and body mass index-matched subsample. There were significant correlations between apnea-hypopnea index and dynamic measures of airway caliber in the retropalatal and retroglossal regions among subjects with apnea.

CONCLUSIONS

Upper airway caliber during respiration was significantly narrower in obese subjects with apnea than obese control subjects in the retropalatal region. These findings provide further evidence that retropalatal airway narrowing plays an important role in the pathogenesis of obstructive sleep apnea in obese subjects.

Evaluation of genial tubercle anatomy using cone beam computed tomography

The purpose of this study was to characterize the anatomy of the genial tubercle using cone beam computed tomography (CBCT). The morphology and detailed anatomy of the genial tubercle were assessed retrospectively in 201 patients (101 females, 100 males) using CBCT images. The parameters examined were the height (GH) and width (GW) of the genial tubercle, the distance from the lower incisors to the superior border of the tubercle (I-SGT), the distance from the inferior margin of the tubercle to the inferior margin of the mandible (IGM-IBM), and the anterior mandible thickness (AMT). Statistical analysis was performed to assess relationships among these parameters, gender, and orthodontic malocclusion (P < 0.05). The values obtained were GH 7.3-8.7 mm, GW 7.9-9.2 mm, I-SGT 7.1-9.1 mm, IGM-IBM 8.3-10.1 mm, and AMT 14.0-16.2 mm. GH, GW, and I-SGT showed no significant differences between genders (P > 0.05). However, IGM-IBM was larger for class III than for class I and class II male patients, and larger than for class I female patients. AMT in class III patients was greater than in class I and II patients (P < 0.05). The use of CBCT, which employs less radiation, is important for dental professionals, especially those performing surgery for obstructive sleep apnea (OSA), in order to avoid possible surgical complications.

Apnea-hypopnea index decreased significantly after nasal surgery for obstructive sleep apnea: A meta-analysis

BACKGROUND

Nasal surgeries have been applied to obstructive sleep apnea (OSA) patients with nasal obstruction for decades. However, the efficiency of nasal surgery in improving OSA remains controversial.The aim of this study was to identify whether isolated nasal surgery can improve apnea-hypopnea index (AHI).

METHODS

Computerized searches were performed in MEDLINE, Web of Science, Cochrane Library, and Scopus from January 1, 2000 to April 30, 2016. A total of 18 articles and 587 participants were included. There were 1 randomized controlled trials, 2 nonrandomized trials, 11 prospective studies, and 4 retrospective studies. Data regarding study design (prospective/retrospective clinical trial, randomized, and controlled), population size, participant characteristics (age, gender, and body mass index), surgical intervention, and outcomes (AHI, Epworth sleep scale [ESS]) was collected.

RESULTS

Statistically significant improvement in AHI (subgroup 1: weighted mean difference [WMD] [95%confidence interval (CI)], -4.17 [-7.62, -0.73]; subgroup 2: WMD [95%CI], -4.19 [-7.51, -0.88]; overall: WMD [95%CI], -4.15 [-6.48, -1.82]) and ESS (subgroup 1: WMD [95%CI], -2.14 [-3.08, -1.19]; subgroup 2: WMD [95%CI], -4.70 [-5.95, -3.44]; overall: WMD [95%CI], -4.08 [-5.27, -2.88]) was revealed.

CONCLUSION

Both AHI and ESS improved significantly after isolated nasal surgery, but the improvement of AHI is slightly significant. Future randomized controlled trials are needed to confirm the long-term benefits of nasal surgery on OSA.

Correlation between the oropharyngo-laryngoscopic findings and the severity of obstructive sleep apnea

OBJECTIVE

To correlate anatomical and functional changes of the oral cavity, pharynx and larynx to the severity of obstructive sleep apnea syndrome (OSAS).

METHODS

We conducted a cross-sectional study of 66 patients of both genders, aged between 21 and 59 years old with complaints of snoring and / or apnea. All underwent full clinical evaluation, including physical examination, nasolarybgoscopy and polisonography. We classified individuals into groups by the value of the apnea-hypopnea index (AHI), calculated measures of association and analyzed differences by the Kruskal-Wallis and chi-square tests.

RESULTS

all patients with obesity type 2 had OSAS. We found a relationship between the uvula projection during nasoendoscopy and OSAS (OR: 4.9; p-value: 0.008; CI: 1.25-22.9). In addition, there was a major strength of association between the circular shape of the pharynx and the presence of moderate or severe OSAS (OR: 9.4, p-value: 0.002), although the CI was wide (1.80-53.13). The septal deviation and lower turbinate hypertrophy were the most frequent nasal alterations, however unrelated to gravity. Nasal obstruction was four times more common in patients without daytime sleepiness. The other craniofacial anatomical changes were not predictors for the occurrence of OSAS.

CONCLUSION

oral, pharyngeal and laryngeal disorders participate in the pathophysiology of OSAS. The completion of the endoscopic examination is of great value to the evaluation of these patients.

Association between pterygoid hamulus length and apnea hypopnea index in patients with obstructive sleep apnea: a combined three-dimensional cone beam computed tomography and polysomnographic study

OBJECTIVE

The purpose of this study was to investigate the relationships among the pterygoid hamulus (PH), the maxillo-mandibular complex to the pharynx, the upper airway, and the soft palate and a possible connection to sleep apnea severity as assessed by polysomnography.

STUDY DESIGN

A total of 100 left and right sides of the PH were retrospectively measured by two observers from 50 cone beam computed tomography images by using three-dimensional rendering program in patients with obstructive sleep apnea (33 males and 17 females, with a mean age of 56.8 years; range 32-82 years).

RESULTS

The mean apnea hypopnea index was 30.2 (range 0-95). A linear regression analysis on the apnea hypopnea index with the total length of the PH adjusted for gender, body mass index, neck circumference, and age showed a statistically significant association: (-0.234(∗); P = .005). None of the other variables reached formal significance.

CONCLUSION

The pterygoid hamulus length is inversely associated with sleep apnea severity. Our study provides further insight into the pathophysiology of sleep apnea, with the result that PH length could be a future supplementary measurement to help clinicians to stratify and determine the best treatment options for patients with obstructive sleep apnea.

The influence of race on the severity of sleep disordered breathing

BACKGROUND

Studies have indicated that the prevalence of obstructive sleep apnea-hypopnea syndrome (OSAHS) is similar between white and African American patients, but it is unclear if there are differences in the severity of OSAHS. We hypothesized that in patients with diagnosed OSAHS, African Americans would have higher apnea-hypopnea index (AHI) and higher mortality than white individuals.

METHODS

We analyzed a prospectively collected database of 512 patients studied between July 1996 through February 1999. Inclusion criteria included age ≥ 18 y, AHI ≥ 5/h, and full-night PSG. Statistical analysis was performed to determine the association between race and AHI while controlling for the effect of confounders and effect modifiers, which included gender, age, body mass index, and comorbidities.

RESULTS

The database included 340 African American and 172 white patients. AHI was higher in African American patients (median 32.7/h IQR 3.3-69.2) than white patients (22.4/h IQR 12.8-40.6, p = 0.01). Age, sex, and BMI were found to be effect modifiers and were included in final models. In the final model, African American men younger than 39 years and between 50 and 59 years were found to have a higher AHI than white men in the same age ranges.

CONCLUSIONS

African American men younger than 39 years and between 50 and 59 years have a higher AHI compared to white men of the same ages after correcting for confounders and effect modifiers. There was no difference in mortality between African Americans and whites with OSAHS in this cohort.

Sleep study, respiratory mechanics, chemosensitive response and quality of life in morbidly obese patients undergoing bariatric surgery: a prospective, randomized, controlled trial

BACKGROUND

Obesity is a major public health problem in both developed and developing countries alike and leads to a series of changes in respiratory physiology. There is a strong correlation between obesity and cardiopulmonary sleep disorders. Weight loss among such patients leads to a reduction in these alterations in respiratory physiology, but clinical treatment is not effective for a long period of time. Thus, bariatric surgery is a viable option.

METHODS/DESIGN

The present study involves patients with morbid obesity (BMI of 40 kg/m2 or 35 kg/m2 to 39.9 kg/m2 with comorbidities), candidates for bariatric surgery, screened at the Santa Casa de Misericórdia Hospital in the city of Sao Paulo (Brazil). The inclusion criteria are grade III morbid obesity, an indication for bariatric surgery, agreement to participate in the study and a signed term of informed consent. The exclusion criteria are BMI above 55 kg/m2, clinically significant or unstable mental health concerns, an unrealistic postoperative target weight and/or unrealistic expectations of surgical treatment. Bariatric surgery candidates who meet the inclusion criteria will be referred to Santa Casa de Misericórdia Hospital and will be reviewed again 30, 90 and 360 days following surgery. Data collection will involve patient records, personal data collection, objective assessment of HR, BP, neck circumference, chest and abdomen, collection and analysis of clinical preoperative findings, polysomnography, pulmonary function test and a questionnaire on sleepiness.

DISCUSSION

This paper describes a randomised controlled trial of morbidly obese patients. Polysomnography, respiratory mechanics, chemosensitive response and quality of life will be assessed in patients undergoing or not undergoing bariatric surgery.

TRIAL REGISTRATION

The protocol for this study is registered with the Brazilian Registry of Clinical Trials - ReBEC (RBR-9k9hhv).

[Pathophysiology of sleep-disordered breathing]

Sleep is a phase during which the respiratory system undergoes major changes. These changes lead to greater vulnerability and a greater risk of abnormalities, even in normal individuals. In the transition from wakefulness to sleep, there is commonly an increase in upper airway resistance and impairment of various protective responses and reflexes, which are efficient in promoting and maintaining upper airway patency during wakefulness. In individuals who present risk factors, such as anatomical abnormalities in the upper airway, these sleep-related changes cannot be efficaciously compensated, which increases the chances that sleep-disordered breathing will occur. Sleep-disordered breathing is characterized by a reduction in the size of upper airways, although the degree of the reduction varies. This reduction has multifactorial causes, which include anatomical abnormalities in the upper airway, alterations in the neuromuscular response and impairment of receptors in the upper airway. Upper airway functional and anatomical changes are likely to have genetic components, and, therefore, individuals exposed to certain environmental factors, such as allergies, have a greater chance of developing sleep-disordered breathing.

Use of Muller's maneuver in the evaluation of patients with sleep apnea - literature review

Sleep apnea-hypopnea syndrome was described twenty years ago, and since then there have been doubts and controversies regarding it. Fiberoptic nasopharyngoscopy with Muller's maneuver, first described by Borowieck and Sassin (1983), is among them.

Aim

Careful literature review on Muller's maneuver, regarding whether it can predict the sucess of uvulopalatopharyngoplasty, location of upper airway obstruction and severity of the disorder.

Discussion and literature rewiew

Literature has shown that there isn't a consensus about the use of Muller's maneuver. In spite of being technically easy, inexpensive and widely used, it is very unespecific and subjective.

Conclusion

The importance of Muller's maneuver in evaluating apneic patients has been questioned, because there are controversies whether it can predict the sucess of uvulopalatopharyngoplasty, location of upper airway obstruction and severity of the disease.

Evaluation of airway obstruction by nasopharyngoscopy: comparison of the Müller maneuver versus induced sleep

The use of nasopharyngoscopy during the application of intrathoracic pressure (Müller maneuver) is frequently employed to establish the site of upper airway obstruction. The Müller maneuver, however, is used when the patient is awake and therefore may not correlate with obstruction occurring during sleep. Aim: to compare the degree of pharyngeal obstruction in the retropalatal and retroglossal regions during the Müller maneuver versus induced sleep using nasopharyngoscopy. Study design: A prospective, case series study. Material and methods: Eight patients (three males, five females), with a mean age of 48.6 +/- 9,2 year, underwent nasopharyngoscopy to assess airway anatomy and funciton during the Müller maneuver while awake and during sleep induced by drip infusion of Midazolam. Results: Retropalatal obstruction was similar during the Müller maneuver and sleep (mean + standard deviation = 3.13 +/- 0.99 and 2.75 +/- 0.46, p= 0.234). Retroglossal obstruction was significantly lower during Müller maneuver compared to sleep (mean + standard deviation 0.63 +/- 1.06 and 2.63 +/- 1.30, respectively, p= 0.005). Conclusion: The sleep inducing method was safe under the monitored conditions of this study, and detected more retroglossal obstruction than the Müller maneuver.

Respiratory and cardiac manifestations of obstructive sleep apnea

Obstructive sleep apnea hypopnea syndrome (OSAHS) is largely under-diagnosed and unrecognized by primary care practitioners. Insidious changes within the respiratory and cardiovascular systems occur over time in untreated OSAHS. Respiratory manifestations of OSAHS include changes in the hypoxic ventilatory response, which can lead to long-term facilitation of ventilation in breathing and production of oxidative stress. Cardiovascular manifestations of OSAHS include increased sympathetic activity, endothelial dysfunction, and over-production of inflammatory cytokines. These changes are likely responsible for many of the pathologic sequelae associated with OSAHS.

Upper airway volume segmentation analysis using cine MRI findings in children with tracheostomy tubes

OBJECTIVE

The purpose of this study is to evaluate the airway dynamics of the upper airway as depicted on cine MRI in children with tracheotomy tubes during two states of airflow through the upper airway.

MATERIALS AND METHODS

Sagittal fast gradient echo cine MR images of the supra-glottic airway were obtained with a 1.5T MRI scanner on seven children with tracheotomy tubes. Two sets of images were obtained with either the tubes capped or uncapped. The findings of the cine MRI were retrospectively reviewed. Volume segmentation of the cine images to compare the airway volume change over time (mean volume, standard deviation, normalized range, and coefficient of variance) was performed for the capped and uncapped tubes in both the nasopharynx and hypopharynx (Signed Rank Test).

RESULTS

Graphical representation of the airway volume over time demonstrates a qualitative increased fluctuation in patients with the tracheotomy tube capped as compared to uncapped in both the nasopharyngeal and hypopharyngeal regions of interest. In the nasopharynx, the mean airway volume (capped 2.72 mL, uncapped 2.09 mL, p = 0.0313), the airway volume standard deviation (capped 0.42 mL, uncapped 0.20 mL, p = 0.0156), and the airway volume range (capped 2.10 mL, uncapped 1.09 mL, p = 0.0156) were significantly larger in the capped group of patients. In the hypopharynx, the airway volume standard deviation (capped 1.54 mL, uncapped 0.67 mL, p = 0.0156), and the airway volume range (capped 6.44 mL, uncapped 2.93 mL, p = 0.0156) were significantly larger in the capped tubes. The coefficient of variance (capped 0.37, uncapped 0.26, p = 0.0469) and the normalized range (capped 1.52, uncapped 1.09, p = 0.0313) were significantly larger in the capped tubes.

CONCLUSION

There is a statistically significant change in airway dynamics in children with tracheotomy tubes when breathing via the airway as compared to breathing via the tracheotomy tube.

Avaliação da obstrução da via aérea superior através da videonasofaringoscopia: comparação da manobra de Müller com o sono induzido

A nasofaringoscopia com realização de Manobra de Müller é freqüentemente utilizada para determinar o local da obstrução na via aérea superior. No entanto, sua utilidade é controversa, uma vez que é realizada com o paciente acordado e pode não reproduzir os fenômenos obstrutivos que ocorrem durante o sono. OBJETIVOS: Comparar o grau de obstrução faríngea nas regiões retropalatal e retrolingual que ocorrem durante a manobra de Müller com aquelas que ocorrem durante o sono induzido. MATERIAL E MÉTODOS: Estudo prospectivo de 8 pacientes (3 homens e 5 mulheres) com idade (média ±desvio padrão) de 48,6 ± 9,2 anos de idade através de videonasofaringoscopia durante a manobra de Müller e durante o sono induzido por midazolam endovenoso. RESULTADOS: Observamos obstrução retropalatal similar durante a manobra de Müller e sono induzido (média + desvio padrão 3,13 + 0,99 e 2,75 + 0,46, respectivamente, p= 0,234). Em contraste, a obstrução retrolingual foi significantemente menor durante a manobra de Müller (média + desvio padrão 0,63 + 1,06 e 2,63 + 1,30, respectivamente, p= 0,005). CONCLUSÃO: O método do sono induzido foi seguro sob as condições de monitorização adotadas, tendo detectado maior ocorrência de colapso retrolingual do que a manobra de Müller.

Prevalence of obstructive sleep apnoea following head and neck cancer treatment: A cross-sectional study

The obstructive sleep apnoea-hypopnoea syndrome (OSAHS) is a sleep-related breathing disorder characterised by repetitive pharyngeal collapse. OSAHS is associated with a reduced quality of life. A high OSAHS prevalence has been reported in patients treated for head and neck cancer (HNC). The aim of the present study was to identify the prevalence of OSAHS within a Dutch population of patients treated for HNC. Consecutive HNC patients with a follow-up of 6 months to 5 years after treatment of an oral or oropharynx carcinoma were eligible for inclusion. Two questionnaires were used to assess the presence of OSAHS-related complaints. Subsequently, polysomnography was used in patients with OSAHS-related complaints to confirm the diagnosis of OSAHS. Four out of 33 included patients were diagnosed with OSAHS, yielding a prevalence of 12%. Since recognition and treatment of OSAHS might play an important role in improving quality of life of HNC patients, we suggest screening all patients with an oral or oropharynx carcinoma for the presence of OSAHS-related complaints prior to and following HNC treatment.

Obstructive sleep apnea and head and neck neoplasms

OBJECTIVE

To elaborate the relationship between obstructive sleep apnea (OSA) and head and neck neoplasms (HNN).

STUDY DESIGN AND SETTING

A systematic review of the MEDLINE literature.

RESULTS

Thirty of 34 articles indexed under OSA and HNN were about neoplasms that presented first as OSA. Four of the articles were about treatment of HNN causing OSA and gave incidences varying from 8% to 92%. Quality of life surveys confirm that patients with malignant HNN have sleep problems. Xerostomia may contribute to these sleep problems, and the role of salivary mucins deserves consideration.

CONCLUSIONS

This review of the literature raises several new research questions about the clinical and biological relationships between OSA and HNN.

Obstructive Sleep Apnea: MR Imaging Volume Segmentation Analysis

PURPOSE

To retrospectively determine airway wall motion with volume segmentation of transverse cine magnetic resonance (MR) images in children with obstructive sleep apnea (OSA).

MATERIALS AND METHODS

Transverse fast gradient-echo cine MR images of the hypopharynx were obtained at 1.5 T in 31 children with OSA (eight girls, 23 boys; mean age, 11.3 years) and 21 children free of airway symptoms who underwent MR imaging for other clinical indications (11 girls, 10 boys; mean age, 3.5 years). Volume segmentation with a k-means clustering algorithm was applied to transverse cine MR images to quantify airway volumes at each time. Airway wall motion for each child was described with standard deviation and range. Coefficient of variance and normalized range, which are independent of airway size, were used to compare groups (Kruskal-Wallis test).

RESULTS

Plots of airway volume over time demonstrated large fluctuations during respiration in children with OSA and minimal fluctuations in controls; findings were consistent with airway distention and airway collapse in OSA. Average airway transverse volume was larger in the group with OSA than in the control group (OSA group, 2.52 mL; control group, 0.936 mL; P <.001). Mean standard deviation (OSA group, 0.840 mL; control group, 0.17 mL; P <.001) and mean range of airway cross section (OSA group, 3.552 mL; control group, 0.864 mL; P <.001) were larger in the group with OSA. Coefficient of variance (OSA group, 0.32; control group, 0.17; P <.001) and normalized range (OSA group, 1.42; control group, 0.96; P <.001) indicate statistically significant difference in airway dynamics in children with OSA.

CONCLUSION

Volume segmentation of transverse cine MR images of the hypopharynx aids in quantification of increased airway wall motion in children with OSA. Transverse MR imaging demonstrates both airway distention and collapse in children with OSA.

Indicação cirúrgica otorrinolaringológica em um ambulatório para pacientes com síndrome da apnéia e hipopnéia obstrutiva do sono

OBJETIVO: Este trabalho tem como objetivo mostrar que o tratamento cirúrgico otorrinolaringológico é uma opção de tratamento para SAHOS e mostrar quais os procedimentos que podem ser realizados e suas indicações. FORMA DE ESTUDO: Clínico retrospectivo. MÉTODO: Realizamos um estudo retrospectivo em 223 pacientes atendidos no ambulatório de Otorrinolaringologia da UNIFESP, onde todos apresentavam polissonografia basal e foram submetidos a anamnese e exame físico otorrinolaringológico. A conduta terapêutica foi dividida em cirúrgica (procedimentos faríngeos, nasais e craniofaciais) e não-cirúrgica (CPAP, aparelho intraoral e medidas gerais). RESULTADOS: Quase metade dos pacientes (100 pacientes - 44,8%) recebeu indicação de algum procedimento cirúrgico, num total de 168 procedimentos, que foram indicados dependendo da gravidade da SAHOS. Desta forma, a uvulopalatofaringoplastia e a radiofreqüência de palato foram indicadas preferencialmente em pacientes com SAHOS leve e moderada e o avanço maxilomandibular em pacientes com SAHOS severa. A amigdalectomia e as cirurgias da cavidade nasal não variaram quanto à gravidade da SAHOS. CONCLUSÃO: O tratamento cirúrgico otorrinolaringológico é uma opção de tratamento para pacientes com SAHOS e pode ter intuito curativo ou coadjuvante a outras terapias, melhorando a adaptação ao CPAP. Os procedimentos cirúrgicos devem ser indicados de forma criteriosa baseando-se na gravidade da doença e nas alterações anatômicas da VAS e do esqueleto facial.

Anaesthetic consequences for a child with complex multilevel airway obstruction -- recommendations for avoiding life-threatening sequelae

A boy with a suspected lymphoid malignancy presented with gross head and neck lymphadenopathy, a middle mediastinal mass, and rapidly worsening airway obstruction. General anaesthesia was required for definitive histopathological diagnosis. The combination of nasopharyngeal obstruction, malignant infiltration of the tonsils and pharynx, laryngeal displacement, and potential tracheal compression put this patient at extreme risk for perioperative airway complications. Risk assessment, and the impact of anaesthesia on pharyngeal neuromechanical function and mediastinal masses are discussed. Caution with volatile anaesthetic agents is recommended in the patient with an inherently unstable pharynx and/or trachea, in whom airway patency relies on a spontaneously breathing technique and intact airway reflexes.

Nasal obstruction in sleep-disordered breathing

It has been 30 years since Cottle suggested that "sleeping patterns are in great measure dependent on good nasal function" [1]. During this time, we have identified the OSAHS and related forms of sleep-disordered breathing such as UARS, and better appreciate the clinical sequelae of recurrent arousals and sleep fragmentation. Yet the exact role that obstructed nasal breathing plays in the pathogenesis of such sleep disorders remains presumptive, and robust clinical studies to corroborate this theory remain elusive; however, patients who may benefit most from correction of nasal obstruction as a sole intervention may be those with the mildest forms of sleep-disordered breathing without other significant predisposing anatomic abnormalities. Clearly, more stringently controlled studies [17,105] are needed, particularly in these types of patients. Until such time, it is reasonable to address issues of nasal obstruction as an adjunct to surgical and nonsurgical treatment in all patients who are diagnosed with a sleep-related breathing disorder.

Effect of testosterone on the apneic threshold in women during NREM sleep

The hypocapnic apneic threshold (AT) is lower in women relative to men. To test the hypothesis that the gender difference in AT was due to testosterone, we determined the AT during non-rapid eye movement sleep in eight healthy, nonsnoring, premenopausal women before and after 10-12 days of transdermal testosterone. Hypocapnia was induced via nasal mechanical ventilation (MV) for 3 min with tidal volumes ranging from 175 to 215% above eupneic tidal volume and respiratory frequency matched to eupneic frequency. Cessation of MV resulted in hypocapnic central apnea or hypopnea depending on the magnitude of hypocapnia. Nadir minute ventilation as a percentage of control (%Ve) was plotted against the change in end-tidal CO(2) (Pet(CO(2))); %Ve was given a value of zero during central apnea. The AT was defined as the Pet(CO(2)) at which the apnea closest to the last hypopnea occurred; hypocapnic ventilatory response (HPVR) was defined as the slope of the linear regression Ve vs. Pet(CO(2)). Both the AT (39.5 +/- 2.9 vs. 42.1 +/- 3.0 Torr; P = 0.002) and HPVR (0.20 +/- 0.05 vs. 0.33 +/- 0.11%Ve/Torr; P = 0.016) increased with testosterone administration. We conclude that testosterone administration increases AT in premenopausal women, suggesting that the increased breathing instability during sleep in men is related to the presence of testosterone.

Gender differences in upper airway compliance during NREM sleep: role of neck circumference

It has been proposed that the gender difference in sleep apnea prevalence is related to gender differences in upper airway structure and function. We hypothesized that men would have smaller retropalatal cross-sectional area and higher compliance during sleep compared with women. Using upper airway imaging, we measured upper airway cross-sectional area and retropalatal compliance in wakefulness and non-rapid eye movement (NREM) sleep in 15 men and 15 women without sleep-disordered breathing. Cross-sectional area at the beginning of inspiration tended to be larger in men compared with women in both wakefulness [194.5 +/- 21.3 vs. 138.8 +/- 12.0 (SE) mm(2)] and NREM sleep (111.1 +/- 17.6 vs. 83.3 +/- 11.9 mm(2); P = 0.058). There was no significant difference, however, after correction for body surface area. Retropalatal compliance also tended to be higher in men during both wakefulness (5.9 +/- 1.4 vs. 3.1 +/- 1.4 mm(2)/cmH(2)O; P = 0.006) and NREM sleep (12.6 +/- 2.7 vs. 4.7 +/- 2.6 mm(2)/cmH(2)O; P = 0.055). However, compliance was similar in men relative to women after correction for neck circumference. We conclude that the gender difference in retropalatal compliance is more accurately attributed to differences in neck circumference between the genders.

Effect of REM sleep on retroglossal cross-sectional area and compliance in normal subjects

It has been proposed that the upper airway compliance should be highest during rapid eye movement (REM) sleep. Evidence suggests that the increased compliance is secondary to an increased retroglossal compliance. To test this hypothesis, we examined the effect of sleep stage on the relationship of retroglossal cross-sectional area (CSA; visualized with a fiber-optic scope) to pharyngeal pressure measured at the level of the oropharynx during eupneic breathing in subjects without significant sleep-disordered breathing. Breaths during REM sleep were divided into phasic (associated with eye movement, PREM) and tonic (not associated with eye movements, TREM). Retroglossal CSA decreased with non-REM (NREM) sleep and decreased further in PREM [wake 156.8 +/- 48.6 mm(2), NREM 104.6 +/- 65.0 mm(2) (P < 0.05 wake vs. NREM), TREM 83.1 +/- 46.4 mm(2) (P = not significant NREM vs. TREM), PREM 73.9 + 39.2 mm(2) (P < 0.05 TREM vs. PREM)]. Retroglossal compliance, defined as the slope of the regression CSA vs. pharyngeal pressure, was the same between all four conditions (wake -0.7 + 2.1 mm(2)/cmH(2)O, NREM 0.6 +/- 3.0 mm(2)/cmH(2)O, TREM -0.2 +/- 3.3 mm(2)/cmH(2)O, PREM -0.6 +/- 5.1 mm(2)/cmH(2)O, P = not significant). We conclude that the intrinsic properties of the airway wall determine retroglossal compliance independent of changes in the neuromuscular activity associated with changes in sleep state.

What are the nonsurgical treatment options for obstructive sleep apnea syndrome?

Obstructive sleep apnea (OSA) syndrome is now recognized as a relatively common cause of excessive daytime sleepiness, with resultant psychosocial impairment and motor vehicle accidents, and it likely contributes to premature cardiovascular disease. Treatment is naturally directed at the upper airway; however, it is also important to identify and correct significant risk factors, such as obesity and hypothyroidism, whenever possible. Oral appliances or nasal continuous positive airway pressure may immediately reverse symptoms caused by OSA and can be used either indefinitely or as a bridge to potentially definitive surgery.

Tension pneumocranium, a rare complication of transsphenoidal pituitary surgery: Mayo Clinic experience 1976-1998

We describe four cases of symptomatic pneumocranium, a rare, potentially life-threatening complication of transsphenoidal pituitary surgery. Symptomatic pneumocranium manifested as impaired mental status, headaches, and grand mal seizures, early in the postoperative course after transsphenoidal pituitary surgery. Furthermore, a Cushing response, including systemic hypertension and bradycardia (secondary to intracranial hypertension) was seen, which has not been previously described in association with symptomatic pneumocranium. We describe a previously unreported risk factor for tension pneumocranium, untreated obstructive sleep apnea. Other factors predisposing to tension pneumocranium in our patients included: cerebrospinal fluid leaks, postoperative positive-pressure mask ventilation, large pituitary tumors, and intraoperative lumbar drainage catheters. Surgical drainage of the pneumocranium and repair of any coexistent cerebrospinal fluid leak markedly improved neurologic status. Symptomatic pneumocranium occurring early in the postoperative course after transsphenoidal pituitary surgery is rare, but prompt recognition and treatment of this condition can be life-saving.