阻塞性睡眠呼吸暂停综合征(OSAS)清醒和呼吸暂停时上气道形态改变的CT动态研究

目的 对比研究OSAS患者清醒和呼吸暂停时上气道的形态学改变。方法 对15例OSAS患者上气道进行清醒和睡眠呼吸暂停时的CT扫描，分析清醒和睡眠呼吸暂停时上气道最狭窄处截面积的动态改变。结果 14例OSAS患者睡眠呼吸暂停时上气道最狭窄处面积比清醒时明显变小，1例上气道最狭窄处完全阻塞。结论 OSAS患者睡眠呼吸暂停时上气道最狭窄处截面积比清醒时明显变小或完全阻塞。     

Relation between CT axial cross-sectional area of the oropharynx and obstructive sleep apnea syndrome in adults.

PURPOSETo look for correlation between obstructive sleep apnea syndrome (OSAS) and axial cross-sectional area of the narrowed oropharyngeal lumen.METHODSThirty-six men with OSAS and 10 control subjects underwent polysomnography with registration of oxygen saturation and number of sleep apnea episodes and their duration. Nine of them underwent uvulopalatopharyngoplasty and repeated polysomnography. Each polysomnography was followed by high-resolution CT scan with reconstructions in sagittal and coronal planes. Measurements of the axial cross-sectional area of the oropharyngeal lumen were taken at the level of the narrowing.RESULTSTwenty-seven patients with severe OSAS (high number and prolonged episodes of OSAS and 22% or greater decrease in oxygen saturation) had a narrowed oropharyngeal cross-sectional area less than 50 mm2 wide. The control subjects and 6 patients who had uvulopalatopharyngoplasty without OSAS had a minimal pharyngeal cross-sectional area of 110 mm2. Eight patients with moderate OSAS and 3 patients who had uvulopalatopharyngoplasty and diagnoses of OSAS had intermediate values of the narrowest pharyngeal level--between 60 mm2 and 100 mm2.CONCLUSIONThe measurement of the axial cross-sectional area of the pharyngeal lumen can play an important role in evaluation of OSAS and indications for surgery.     

Evaluation of the upper airway cross-sectional area changes in different degrees of severity of obstructive sleep apnea syndrome: cephalometric and dynamic CT study

BACKGROUND AND PURPOSE: The upper airway lumen is narrower in patients with obstructive sleep apnea syndrome (OSAS) than normal subjects. In this study, we examined changes of the upper airway cross-sectional area in each phase of respiration in different degrees of severity of OSAS with dynamic CT and investigated whether these changes have any correlation with sleep apnea severity parameters, including polysomnography (PSG) and cephalometry. MATERIALS AND METHODS: Between May and November 2004, 47 patients who had at least 2 of 3 major symptoms of snoring, daytime somnolence, and apnea with witness were included in this prospective study. As control group, 24 habitual snorers were studied. All patients underwent PSG and upper airway CT. The average number of episodes of apnea and hypopnea per hour of sleep (the apnea-hypopnea index, AHI) was calculated. An AHI of 5 -29 represented mild/moderate OSAS and an AHI > or = 30 represented severe OSAS. Cross-sectional area of the airway at the level of oropharynx and hypopharynx were obtained in each phase of quiet tidal breathing and at the end of both the forced inspiration and expiration. Six standard cephalometric measurements were made on the lateral scout view. All parameters were compared between controls and mild/moderate and severe OSAS groups. RESULTS: Twenty-seven patients had mild/moderate OSAS, and 20 patients had severe OSAS. Patients with severe OSAS had significantly narrower cross-sectional area at the level of uvula in expiration, more inferiorly positioned hyoid bone, and thicker soft palate compared with patients with mild/moderate OSAS (P < .05) and the control group (P < .05). In addition, severe OSAS patients had bigger neck circumference than those in the control group (P < .05). CONCLUSION: Patients with severe OSAS had significant differences in the parameters. Measurement of the cross-sectional area of oropharynx in expiration can especially be useful for diagnosis of severe OSAS as a new key point.     

Occlusion and narrowing of the pharyngeal airway in obstructive sleep apnea: evaluation by ultrafast spoiled GRASS MR imaging.

Morphologic abnormalities of the pharyngeal airway are frequently found in patients with obstructive sleep apnea. These structural alterations in the pharyngeal airway can be detected in awake patients by using rapid imaging techniques. Ten patients with clinically proved obstructive sleep apnea had ultrafast spoiled gradient-recalled acquisition in the steady state (GRASS) MR imaging of the pharyngeal airway to determine the presence of occlusions and/or narrowings. Twelve sequential images were obtained at one midsagittal plane and at eight transverse planes through the pharyngeal airway. The scans were obtained at the rate of one image per 1.04 sec while the patient was breathing quietly. Occlusions or narrowings of the pharyngeal airways were detected on MR images in all patients. The site(s) of the occlusions and the site(s) and extent of the narrowings varied. Six patients had occlusions and four had narrowings of one or more sites. This study shows that ultrafast spoiled GRASS MR imaging can be used to evaluate patients with obstructive sleep apnea during tidal breathing and is useful for determining the presence of occlusions and narrowings of the pharyngeal airway.     

Cine CT in obstructive sleep apnea

The upper airway was evaluated in eight patients with obstructive sleep apnea by using a rapid sequential CT scanner (Imatron C-100). Four patients also had simultaneous polysomnograms to determine the onset of sleep and apnea. The upper airway was scanned while the patient was awake (eight patients), asleep (four patients), and asleep and apneic (eight patients). Measurements of the cross-sectional area of the upper airway were correlated with the findings on sleep studies in four patients. During the awake state the airway was narrowed and showed increased collapsibility in all eight patients. Five of the eight patients had cross-sectional areas of less than or equal to 4 mm2 at one or more sites at some time during the respiratory cycle while awake. During apnea all patients had obstruction at the uvula and oropharynx, but the length of the obstruction varied from one patient to another. In three of the eight patients the obstruction extended inferiorly to the hypopharynx. Cine CT can be used to objectively evaluate patients with sleep apnea and may demonstrate the need to modify surgical treatment.     

Computed tomography of the oropharynx in obstructive sleep apnea

Uvulopalatopharyngoplasty (UPPP) is currently the preferred method for treatment of the obstructive sleep apnea syndrome (OSAS). However, only 50 per cent of the patients operated upon are cured by this surgical procedure, and there is a demand for better and more objective selection criteria. Computed tomography (CT) of the oropharynx was obtained in 32 consecutive adult patients with proven OSAS. An additional 15 patients with the same complaints, but without objective evidence of OSAS, were used as a control group, together with 20 normal subjects. The axial widths of the tongue and the genioglossus and hyoglossus muscles were measured by CT. Both the tongue and genioglossus widths were significantly larger in the OSAS patients than in the two control groups (p less than 0.001). The increased tongue width will cause encroachment of the oropharyngeal airway below the level of the soft palate. Thus, CT can be used to measure the tongue size in order to evaluate its predictive value for the outcome of the UPPP procedure.     

Dynamic upper airway soft-tissue and caliber changes in healthy subjects and snoring patients

BACKGROUND AND PURPOSE: The oropharyngeal airways are smaller in those who snore than in those who do not. We sought to determine which soft-tissue component surrounding the airways contributes to upper airway narrowing in those who snore. METHODS: Ten control subjects and 19 snoring patients underwent CT, with 2-mm-thick axial sections obtained every 0.6 seconds during the respiration cycle at the same oropharyngeal level. We selected two sections with the widest and narrowest parts of the oropharyngeal airway to measure the anteroposterior and lateral dimensions of the airway and the thickness of the bilateral parapharyngeal fat pads, pterygoid muscles, and parapharyngeal walls. Mean values were calculated for each phase. For each subject, differences were calculated by subtracting the values in narrowest phase from those in the widest phase. RESULTS: Changes in airway dimension (P < .05) and lateral parapharyngeal wall thickness (P < .01) were significantly different between snorers and control subjects. Changes in parapharyngeal wall thickness and transverse oropharyngeal airway diameter changes were significantly related (P < .01) in those who snored but not in control subjects. CONCLUSION: Airway narrowing predominantly occurs in the lateral dimension in people who snore. Changes in the lateral pharyngeal wall are more important than the parapharyngeal fat pads in airway calibration. Narrowing of the upper airway area at the end of the expirium and the beginning of the inspirium is thought to be the cause of snoring and due to augmented muscle mass and prolonged laxity rather than inadequate activation of the pharyngeal dilating muscles.     

Computed tomographic cephalometric analysis of Chinese patients with obstructive sleep apnoea

Variations of craniofacial and upper airway structures are recognized to contribute to the phenomenon of obstructive sleep apnoea (OSA). Most previous cephalometric studies were performed using erect lateral radiographs in Caucasian patients. The present project aims to determine cephalometric measurements, utilizing CT, in normal Chinese subjects and in Chinese patients with OSA. Computed tomography of 25 patients with OSA (proven using overnight polysomnography), and of 25 age-, sex-, height-, bodyweight- and body mass index (BMI)-matched control subjects were prospectively performed. Thirteen standard bony and soft-tissue measurements were obtained from the CT lateral scout view of the head and neck, taken with each subject in the neutral supine position. The cross-sectional area was calculated at two axial levels (velopharynx and hypopharynx). The measurements in the two groups, OSA and control subjects, were compared. The measurements for hyoid position (P = 0.00), nasal cavity length (P = 0.01), mandibular prognathism (P = 0.05), tongue size (P = 0.02), oropharyngeal airway space (P = 0.02), posterior tongue airway space (P = 0.04) and cross-sectional areas at the level of the velopharynx (P = 0.00) and hypopharynx (P = 0.01) differed significantly between the two groups. In conclusion, CT cephalometric measurements show that certain anatomical variations in the head and neck are likely to contribute to the pathogenesis of OSA in Chinese patients.     

Upper airway motion depicted at cine MR imaging performed during sleep: comparison between young Patients with and those without obstructive sleep apnea

PURPOSE: To compare the patterns of dynamic airway motion depicted on cine magnetic resonance (MR) images obtained during sleep between young patients with and those without obstructive sleep apnea (OSA). MATERIALS AND METHODS: Fast gradient-echo sequences were performed in the sagittal midline by using a 1.5-T unit to create cine MR images. Cine MR images obtained during sleep in 16 young patients with OSA were compared with those obtained in 16 young patients with no airway symptoms of airway disease. The nasopharynx, oropharynx, and hypopharynx were characterized in terms of airway motion as static patent (SP), dynamic patent, intermittent collapsed (IC), or static collapsed (SC); and the maximal diameter and greatest change in diameter (in millimeters) of these airways were calculated. Adenoid tonsil size and mouth position (ie, opened or closed) were determined. Differences in the frequency of MR imaging parameters in the different anatomic regions were evaluated by using Fisher exact, chi 2, and sample t tests. RESULTS: There were statistically significant differences in the following parameters between the two groups: nasopharynx SP (P <.001) and IC (P <.001); hypopharynx SP (P <.001) and IC (P <.001); and mean change in airway diameter of the nasopharynx (P <.001) and hypopharynx (P <.001). The mean adenoid tonsil size in the patients with OSA was larger (P =.006). CONCLUSION: There are significant differences in the patterns of dynamic airway motion between young patients with and those without OSA.     

CT demonstration of pharyngeal narrowing in adult obstructive sleep apnea

Sleep apnea is a major cause of daytime hypersomnolence. Among the proposed etiologies, focal obstruction of the airways at the level of the pharynx has been suggested but not proven. Using computed tomography, the cross-sectional area of the airway can be readily assessed. Thirty-three adults with clinically proven sleep apnea and 12 normal adults underwent systematic computed tomography of the neck. Significant airway narrowing was demonstrated in all the patients with obstructive sleep apnea, whereas no such narrowing was seen in the controls. In 11, the narrowing was at a single level, whereas in 22 patients two or more levels were affected. This study has shown that a structurally abnormal airway may serve as an anatomic substrate for the development of sleep apnea. On the basis of this evidence, uvulopalatopharyngoplasty has been performed in two patients with relief of symptoms in one.     

A cephalometric comparison of normal weight and obese subjects with obstructive sleep apnoea

Purpose: To compare the skeletal, oropharyngeal and soft tissue features of two groups of subjects with obstructive sleep apnoea (OSA) using lateral cephalometric radiographs. One group of subjects exhibited a normal body mass index, whilst the other was obese.Methods: Lateral cephalometric radiographs of 48 dentate, white, Caucasian males with confirmed OSA were traced and digitized and comparisons were sought between the skeletal and oropharyngeal morphologies of the two groups. Twenty-eight subjects were obese and 20 individuals exhibited normal body mass indices (BMI). Mann–Whitney U-tests were employed to examine differences between the two groups and a P value of less than 0.05 was considered significant.Results: Subjects with a normal BMI exhibited significantly more retruded maxillae, more upright incisors, smaller mandibles and a shorter distance between the lower incisor and the posterior pharyngeal wall than obese subjects. In the latter group, the length of the lower face was increased. In addition, the lengths and cross-sectional areas of both the soft palate and tongue were significantly larger. The hyoid was further away from both the chin (menton) and the cervical column (C3) in this group. No differences were found in minimum airway dimensions or in the cross-sectional area of the oropharynx between the groups although, as expected, these dimensions were reduced in comparison with control values.Conclusions: Obstructive sleep apnoea subjects of normal weight have more anterior–posterior dentofacial abnormalities than their obese counterparts. However, both groups are clearly distinguishable from control individuals. In the obese subjects, additional soft tissue anomalies are found. It would therefore seem that all OSA subjects exhibit some anatomical basis for their condition, but this is compounded by soft tissue factors in obese individuals. It is therefore doubtful whether loss of weight in obese subjects would significantly influence the severity of the condition.     

阻塞性睡眠呼吸暂停低通气综合征MSCT研究

目的:评价上气道多层螺旋CT多呼吸时相扫描及后处理技术对阻塞性睡眠呼吸暂停低通气综合征(OSAHS)的诊断价值.方法:对68例OSAHS患者和65例健康志愿者分别在平静呼吸、深吸气末、深呼气末及闭口堵鼻深吸气(Müller呼吸)这4个呼吸时相于清醒状态下行上气道MSCT扫描,测量不同呼吸时相鼻咽区、腭咽区、舌咽区和会厌...     

多层螺旋CT对阻塞性睡眠呼吸暂停综合征手术前后上气道测量的价值

目的 了解MSCT对评价阻塞性睡眠呼吸暂停综合征(OSAS)患者手术前、后上气道变化及手术疗效的价值.方法 应用16层螺旋CT MPR、CPR及VR等方法测量26例OSAS患者上气道,比较分析手术前、后上气道矢状面重组图像轴面层面咽腔的前后径和面积、腭后区及舌后区最小面积层的各径线和面积及相对位置、软腭悬雍垂最厚处厚度及矢状面上的面积、冠状面CPR图像上最厚左右侧壁厚度、上气道容积;并与多导睡眠(PSG)监测结果进行相关性分析.数据分析应用Paired-Samples t检验或Pearson直线相关分析.结果 与术前比较,手术后患者在矢状面重组后再行轴面重组图像上,上气道腭后区下部(第4层)前后径及面积明显增加[前后径手术前为5.9 mm,手术后为12.8 mm;面积手术前为51.0 mm~2,手术后为275.0 mm~2,t值分别为-5.506、-5.011,P值均<0.05].上部(第2层)显著减小[前后径手术前为14.8 mm,手术后为9.2 mm;面积手术前为241.0 mm~2,手术后为128.0 mm~2,t值分别为2.867、3.087,P值均<0.05].舌后区(第7层)术后前后径明显减小[手术前为12.7mm,手术后为10.3 mm,t=3.718,P<0.05].最小面积层腭后区左右径、面积手术后显著增加[左右径手术前为6.4 mm,手术后为10.9 mm;面积手术前为33.0 mm~2,手术后为76.0 mm~2,t值分别为-3.413、-2.216,P值均<0.05].临床治愈的9例OSAS患者手术前、后的CT测量结果:应用矢状面重组后再行轴面重组方法测量,9例手术治愈患者(术后呼吸暂停指数(AHI)≤5次/h)腭后区最小面积层面积、前后径及左右径均较术前明显增大[面积手术前为41.0 mm~2,手术后为76.0 mm~2,前后径手术前为4.6 mm,手术后为6.6 mm;左右径手术前为8.3 mm,手术后为13.6 mm;t值分别为-4.932、-7.308、-4.320,P值均<0.05].结论 MSCT的MPR、CPR及VR等重组方法,能较好评估OSAS患者上气道,不仅可以很好地显示解剖结构的变化,也可能提示继发的功能变化.最小面积层相应径线增大可能是评价手术有效的很有意义指标之一.术后腭后区上部可能存在的狭窄需引起临床医师注意.     

128层螺旋CT三维重建对OSAHS患者上气道应用价值的研究

目的：评估128层螺旋 CT 上气道三维重建对阻塞性睡眠呼吸暂停低通气综合征(OSAHS)患者上气道阻塞部位的定位价值。方法采用128层螺旋 CT 对52例确诊的 OSAHS 患者清醒和 Muller 试验下及32例正常人清醒状态下进行上气道容积扫描,分别测量软腭后区、舌后区及会厌后区的气道体积和气道长度,并对各测量指标进行统计学分析。结果与正常对照组相比,清醒状态下 OSAHS 患者上气道长度显著增加(P <0.001)。与清醒状态下相比,OSAHS 患者 Muller 试验下软腭后区气道体积、舌后区气道体积、气道总体积显著减少(P <0.001)。OSAHS 患者上气道长度与平均血氧饱和度(MSaO2)呈负性相关(r=-0.33, P <0.05)。结论128层螺旋 CT 上气道三维重建能较好评估 OSAHS 患者上气道阻塞部位及阻塞的程度,对指导临床治疗有重要意义。     

CPAP疗法对于合并OSA老年2型糖尿病患者血糖控制及睡眠质量影响

目的探讨持续气道正压通气(CPAP)疗法对合并阻塞性睡眠呼吸暂停(OSA)的老年2型糖尿病(T2DM)患者的血糖以及睡眠呼吸暂停的影响。方法选择2015年1月至2016年7月长江航运总医院武汉脑科医院收治的患有T2DM同时伴有新诊断的OSA的49例老年患者为研究对象。根据患者是否愿意接受CPAP治疗,分为CPAP组(n=20)和常规组(n=29)。CPAP组进行CPAP治疗,常规组使用口腔阻鼾器治疗。治疗前及治疗12周后,分别使用动态血糖监测系统(CGMS)以及多导睡眠监测对患者的血糖指标以及睡眠质量相关指标进行测定。结果经过12周的治疗,与治疗前及常规组治疗后比较,CPAP组患者的体质量、平均血糖波动幅度(MAGE)、平均日间血糖差异(MODD)、空腹血糖、氧减指数(ODI)、呼吸暂停低通气指数(AHI)、ESS指标均显著下降,平均血氧饱和度(SaO_2)显著上升(P<0.05),但糖化血红蛋白(Hb A1c)的下降无统计学意义(P>0.05)。结论合并OSA的T2DM老年患者接受CPAP治疗后,空腹血糖水平显著下降且血糖波动更小,睡眠呼吸暂停和低通气以及白天嗜睡状况均得到显著改善,睡眠质量得到极大提高。     

Is sedation safe during dynamic sleep fluoroscopy of children with obstructive sleep apnea?

OBJECTIVE: Airway compromise is considered a relative contraindication for pediatric sedation. This contraindication presents a paradoxical problem when patients require sedation in preparation for imaging performed to evaluate the cause of airway obstruction. We use dynamic sleep fluoroscopy in the evaluation of children who have obstructive sleep apnea. The purpose of this study was to evaluate the success and safety of a structured sedation program for dynamic sleep fluoroscopy. MATERIALS AND METHODS: Eighty consecutive dynamic sleep fluoroscopic studies were evaluated. The type of sedation used, success rate, complications related to the sedation, and characteristics of the children studied were reviewed. Patients were sedated in accordance with our departmental sedation program guidelines. Findings on fluoroscopy were correlated with episodes of oxygen desaturation or noisy breathing. RESULTS: In all 80 cases, dynamic sleep fluoroscopy was successfully performed. Seventy-two studies were performed, with sedation supervised by the radiologist. Four patients fell asleep without sedation. In four patients, sedation was performed by an anesthesiologist (preprocedural decision). Sixty-four children (80%) had complex medical problems, and 39 (49%) had a history of previous airway surgery. All studies were considered successful. Specific diagnoses were identified in 66 children (83%). No children suffered complications or required tracheal intubation. CONCLUSION: Children with airway compromise who are being evaluated for obstructive sleep apnea can be successfully and safely sedated for dynamic sleep fluoroscopy when a structured sedation program is used.     

螺旋CT和便携睡眠监测阻塞定位仪评估OSAHS上气道狭窄

目的:研究螺旋CT和便携睡眠监测阻塞定位仪(apnea graphy,AG)在阻塞性睡眠呼吸暂停低通气综合征(OSAHS)诊断中的临床应用价值。方法:22例睡眠打鼾患者,便携睡眠监测阻塞定位仪进行整夜睡眠呼吸监测,分析呼吸紊乱指标、出现呼吸暂停低通气事件时的阻塞平面,不同平面的阻塞次数和总阻塞次数。上气道多层螺旋CT自鼻咽部顶壁平扫至环状软骨下缘平面,测量清醒状态下上气道的软腭后区、舌后区气道的横截面积及冠、矢状径。将AG测定上气道狭窄平面与CT测量判断平面进行比较。结果:①22例患者均很好耐受整夜AG监测,16例符合OSAHS,其中轻度2例,中度8例,重度6例。6例排除OSAHS;②16例OSAHS中AG测压均为上部和下部联合阻塞,上部阻塞为主13例,其中1例上部阻塞为100%,下部阻塞为主3例。不同病例上部、下部阻塞频度不同,多为上部阻塞为主;③22例CT测量中4例无狭窄平面,14例腭后区狭窄,1例舌后区狭窄,3例腭后区、舌后区双重狭窄;④16例OSAHS中,AG测压腭后区阻塞为主13/16,CT测量腭后区狭窄12/16,无统计学差异(P>0.05)。AG测压下部阻塞为主3/16,CT测量舌后区阻塞4/16。结论:AG作为便携PSG对OSAHS定性定位诊断具有重要作用,结合CT测量可以很好地评估上气道腭后区狭窄。     

儿童阻塞性睡眠呼吸暂停低通气综合征的上气道低剂量多层螺旋CT表现

目的分析儿童阻塞性睡眠呼吸暂停低通气综合征(OSAHS)的上气道多层螺旋CT(MSCT)表现及其应用价值。方法对36例经多导睡眠监测(PSG)确诊的儿童OSAHS患者,采用16层多层螺旋CT行上气道低剂量扫描,进行冠、矢状面及垂直气道长轴的斜位断面重建,测量鼻咽、口咽上部、口咽下部及喉咽咽腔横截面积,分析儿童OSAHS的上气道狭窄原因及解剖学定位。并选择阴性对照组,检查与测量方法同OSAHS患儿组,对比OSAHS患儿与无鼾症儿童是否存在显著性差异。结果36例儿童OS-AHS患者鼻咽、口咽上部及口咽下部咽腔横截面积明显小于对照组,两者存在显著性差异。患儿均可见腺样体肥大与扁桃体肿大,其中腺样体咽腔比值(A/N)≥0.71者32例,占88.9%;扁桃体Ⅲ°肿大33例,占91.7%。结论儿童OSAHS存在上气道解剖学狭窄,低剂量MSCT扫描是检查儿童OSAHS上气道可靠方法。     

Pulmonary involvement in Churg-Strauss syndrome: an analysis of CT,clinical, and pathologic findings

We tried to assess retrospectively thin-section CT findings of Churg-Strauss syndrome (CSS) in 25 patients and to compare these findings with clinical and histopathologic findings. Of 25 patients, 19 (76%) had parenchymal abnormalities at CT; small nodules (n = 12; 63%), ground-glass opacity (n = 10; 53%), bronchial wall thickening (n = 10; 53%), and consolidation (n = 8; 42%). Parenchymal abnormalities (n = 19) were categorizable as an airway pattern in 11 and an airspace pattern in eight. Patients with an airway pattern (n = 5) had obstructive (n = 3) or combined (n = 2) PFT results, whereas those with an airspace pattern (n = 4) had restrictive (n = 3) or obstructive (n = 1) results. Parenchymal opacities at CT corresponded histologically to areas of eosinophilic pneumonia, necrotizing granulomas, and granulomatous vasculitis; small nodules to eosinophilic bronchiolitis and peribronchiolar vasculitis; and bronchial wall thickening to airway wall eosinophil and lymphocyte infiltration. Patients with airspace pattern responded more readily to treatment than those with airway pattern. CT shows lung parenchymal abnormalities in about three-quarters of CSS patients and these abnormalities can be categorized as airspace or airway patterns. This classification helps predict PFT data, underlying histopathology, and treatment response.     

How to treat patients with obstructive sleep apnea syndrome during an altitude sojourn

Considering the high prevalence of the obstructive sleep apnea syndrome (OSA), it is expected that many patients with the disorder are traveling to altitude. However, this may expose them to the risk of pronounced hypoxemia, exacerbation of nocturnal breathing disturbances by frequent central apneas, impaired daytime performance, and high blood pressure. Recently, randomized studies specifically investigated the effects of altitude (1630-2590 m) in OSA patients and the optimal treatment in this setting. The results indicate that patients should continue to use continuous positive airway pressure therapy (CPAP) when sleeping at altitude. Since CPAP alone does not control central sleep apnea emerging at altitude, combined treatment with acetazolamide and CPAP should be considered, in particular, in patients with severe OSA and co-morbidities. Supplemental oxygen combined with CPAP might be advantageous in patients with OSA and concomitant cardiopulmonary disease by preventing hypoxemia and central sleep apnea. In patients unable to use CPAP or if electrical power is not available, an optimally fitted mandibular advancement device might be an alternative treatment option that can be combined with acetazolamide during altitude sojourns. Acetazolamide alone is also beneficial and better than no treatment at all, since it improves oxygen saturation, breathing disturbances, and the excessive blood pressure elevation in OSA patients traveling to altitude.