Evidence for increased intracranial pressure in high altitude pulmonary edema

We sought to determine if optic nerve sheath diameter (ONSD), a surrogate measure of ICP, is increased in high altitude pulmonary edema (HAPE). Five HAPE patients (one with a codiagnosis of high altitude cerebral edema [HACE]) treated at the Himalayan Rescue Association clinic in Pheriche, Nepal (4240 m), underwent optic nerve sheath ultrasonography (ONSU) at admission to determine ONSD. Results were compared to ONSD in 32 control subjects at the same altitude without evidence of altitude illness. Four of the five HAPE patients underwent repeat ONSU at discharge. All exams were read by two blinded observers. The mean ONSD for HAPE patients on presentation was 5.7 +/- 0.44 mm and for controls was 4.7 +/- 0.56 mm (p = 0.003). Excluding the patient with a coexistent clinical diagnosis of HACE, mean ONSD at presentation for the other four HAPE patients was 5.7 +/- 0.50 mm and was significantly different from controls (p = 0.007). In the four HAPE patients with repeat exams, ONSD decreased by 17% +/- 15% (95% CI 4-30%) between admission and discharge. We conclude that HAPE is associated with increased ONSD, a surrogate measure of increased ICP.     

Erythropoietin levels in lowlanders and high-altitude natives at 3450 m

BACKGROUND: This study is aimed to determine whether short or prolonged residency at high altitude (HA) elicits erythropoietin (EPO) secretion effectively in subjects who were able to acclimatize and those who were not able to acclimatize and suffered from acute mountain sickness (AMS) and high altitude pulmonary edema (HAPE). METHODS: Plasma EPO was measured in 16 lowland residents (LLR) at sea level (SL) and during 11 d of their sojourn at an altitude of 3450 m. Identical studies were also conducted in LLR acclimatized to HA (LLR-accl), high altitude natives (HAN) and in patients of AMS and HAPE. RESULTS: In LLR at SL, the mean +/- SD EPO levels were 8.93 +/- 3.75 mU x ml(-1), increased significantly after 8 h (20.0 +/- 11.06) of arrival at HA, peaked by day 1 (27.91 +/- 10.74 mU x ml(-1)), and started declining thereafter. The hemoglobin and hematocrit also increased after 8 h of arrival at HA and the increased levels were maintained during sojourn at high altitude. The EPO levels in LLR-accl were found to be significantly higher than the LLR SL values, but were not significantly different in HAN. The EPO levels in patients of AMS were not significantly different than the LLR values during the initial 2 d after arrival at HA but were found to be increased in patients of HAPE. CONCLUSION: Short or prolonged residency at HA is associated with increased secretion of EPO. The EPO response to hypoxia is not significantly altered in AMS but is markedly enhanced in HAPE, which may be due to exaggerated hypoxemia in these patients.     

Altitude illness: update on prevention and treatment

ABSTRACT: Altitude illness is a broad category of disease encompassing acute mountain sickness (AMS), high-altitude cerebral edema (HACE), and high-altitude pulmonary edema (HAPE) that can affect persons who travel to altitude without adequate acclimatization. Initial symptoms of AMS and the more serious HACE or HAPE can be subtle, and it is important that the practitioner be able to recognize and differentiate between these diagnoses because they can progress rapidly and be fatal if untreated. There are well-established criteria and many proven therapies both for prophylaxis and treatment of altitude illness; however, despite intense research efforts, the specific mechanisms of these complex diseases remain elusive. Adequate acclimatization via controlled ascent remains the most important factor in preventing altitude illness, although prophylactic pharmacotherapy also may be useful. Rapid descent remains the most important treatment factor, although treatment at altitude with various therapies is possible for mild cases with adequate resources.     

A pig model of high altitude pulmonary edema

High altitude pulmonary edema (HAPE) affects unacclimatized individuals ascending rapidly to high altitude. The pathogenesis of HAPE is not fully elucidated, and many investigative techniques that could provide valuable information are not suitable for use in humans; thus, an animal model is desirable. Rabbits, sheep, dogs, and ferrets have been shown not to consistently develop HAPE, and studies in rats are limited by the animal's small size and inconsistent response. Pigs develop a marked pulmonary vasoconstrictive response to hypoxia, and preliminary studies of HAPE in pigs have been promising. To determine the suitability of pigs as an animal model of HAPE, we exposed six subadult (20 to 25 kg) pigs to normobaric hypoxia (10% oxygen) for 48 hr. One week before, and immediately after exposure to hypoxia, under anesthesia, arterial blood gases were obtained and bronchoalveolar lavage (BAL) and chest x-ray were performed. Hypoxia increased alveolar-arterial pressure difference for oxygen from 22 +/- 9 to 38 +/- 5 torr, p < 0.01) and red cell (from 12.3 +/- 5.9 to 27.4 +/- 5.3 cells x 10(5)/mL(-1), p < 0.001) and white cell (from 1.59 +/- 0.90 to 7.88 +/- 3.36 cells x 10(5)/mL(-1), p < 0.05) concentrations in BAL in all animals. Total BAL protein concentration increased by 64% and fractional albumin by 38% (both p < 0.05) posthypoxia. One animal had evidence of pulmonary edema on X ray. Some pigs develop findings consistent with early HAPE when exposed to normobaric hypoxia. Increasing the duration of hypoxic exposure or exercising the animals in hypoxia may better model the disease process observed in humans with clinically significant HAPE.     

Do changes in lung function predict high-altitude pulmonary edema at an early stage?

PURPOSE: Ascent to high altitude is associated with alterations in lung function. The mechanisms of these changes and whether they reflect early stages of high-altitude pulmonary edema (HAPE) has been debated. Therefore, we investigated the time course of pulmonary function in relation to hemodynamics and clinical symptoms in mountaineers ascending rapidly to high altitude. METHODS: In 26 unacclimatized subjects we assessed spirometry, single-breath nitrogen washout, diffusing capacity (DLCO), and Doppler echocardiography in Zurich, 490 m, after climbing within 24 h to Monte Rosa, 4559 m, and after one night at 4559 m. RESULTS: Mean (+/- SD) FVC fell from 103 +/- 9% predicted in Zurich to 96 +/- 10% predicted at 4559 m, FEV1/FVC increased from 0.82 +/- 0.06 to 0.84 +/- 0.08, and closing volume increased from 0.35 +/- 0.14 to 0.44 +/- 0.11 L above residual volume (P < 0.05, all changes). On the following day at 4559 m, closing volume remained elevated in 9 of 21 subjects who had a lower DLCO but similar pulmonary artery systolic pressures compared with the remaining 12 subjects (40 +/- 8 vs 43 +/- 7 mm Hg, P = NS). None of the subjects had overt HAPE. CONCLUSION: We conclude that changes in pulmonary function after rapid ascent to high altitude were consistent with interstitial fluid accumulation, but they were not related to changes in pulmonary artery pressure. Individual lung function responses to high-altitude exposure varied largely and did not predict subsequent HAPE.     

高原肺水肿的CT诊断

目的：探讨高原肺水肿的CT诊断价值。方法：对16例急性高原适应不全患者进行胸部CT检查，总结其CT表现。结果：其CT表现：（1）早期为磨玻璃样密度增高影，多出现于下叶背段及后基底段，且右下叶早于左下叶；（2）中期为云状密度增高影，若早期未得到及时有效的治疗，则病变密度逐渐增高而形成云絮状密度增高影；（3）晚期可发展到上叶后段及前段，病变充满整个肺叶，可见受累肺段支气管充气；（4）右肺表现重于左肺。结论：CT是高原肺水肿较理想的检查手段。对于高原肺水肿，CT诊断的准确率达100％。     

高原肺水肿患者血清肌钙蛋白T研究

目的 :探索高原肺水肿 (HAPE)患者血清肌钙蛋白 T(cTnT)的变化。方法 :放免法测定HAPE患者在一氧化氮(NO)治疗前后血清cTnT。结果 :cTnT治疗前显著高于治疗后 (P <0 0 1) ,SaO2 治疗后显著高于治疗前 (P <0 0 0 1) ,治愈率为 10 0 0 %。结论 :对较重的HAPE患者有心肌损害和心功能的下降 ;NO治疗HAPE是非常有效的 ,为HAPE治疗提供了新的方法     

高原肺水肿影像表现及其病理基础的实验研究

目的探讨高原肺水肿的影像特点及其病理基础.材料与方法利用减压舱模拟海拔7000m高原条件观察家猫缺氧24、48和72小时胸部X线、CT表现及其病理改变.结果实验性高原肺水肿早期X线、CT表现为肺纹理增粗、模糊,肺野周围性分布的斑片状阴影.减压组动物减压后右下肺动脉横径较减压前显著增加(P＜0.05),胸片肺水肿记分与CT值呈显著的线性正相关(r=0.955).主要病理改变为肺出血及肺水肿.结论高原肺水肿胸部X线、CT主要表现为肺野周围性分布的斑片状阴影,对高原肺水肿的诊断有重要意义.     

重组人脑利钠肽治疗高原肺水肿的肺动脉压变化

目的 观察重组人脑利钠肽（rhBNP）治疗高原肺水肿（HAPE）的肺动脉平均压（MPAP）变化情况,进一步明确rhBNP治疗HAPE的机制.方法 收集我院2011年2月~2012年10月收治的HAPE患者98例,随机分为常规治疗组和rhBNP组.两组入院后都给予吸氧、利尿、镇静、扩张支气管、减轻心脏负荷等处理,rhBNP组同时给予rhBNP治疗,然后监测两组入院前及治疗24 h后MPAP的变化,比较两组降MPAP效果.结果治疗24 h后,rhBNP组MPAP较对照组明显降低（P＜0.01）,rhBNP组未发生药物相关的不良事件.结论 肺动脉压升高是HAPE的机制之一,rhBNP可降低HAPE患者的MPAP,为其治疗HAPE提供了理论依据.     

高原肺水肿398例临床分析

目的：探讨高原肺水肿的临床特点，总结其诊治经验；方法：对我院1986年6月至2001年4月收住的资料较为完整的高原肺水肿患者临床资料进行回顾性分析研究；结果：海拔4000m以上者发病178例，占44.72%；以上呼吸道感染为诱因发病者172例，占43．22％；X线表现单侧肺病变以右肺为多；窦性心动过速为心电图异常主要类型，占62．31％；合并高原脑水肿者死亡9例，占死亡的75％，是导致死亡的重要因素；结论：高原肺水肿海拔愈高，发病率愈高；上呼吸道感染可诱发高原肺水肿；合并高原脑水肿者，病死率明显增高。     

2 016例高原肺水肿现场救治体会

目的：寻找现场有效救治高原肺水肿的方法和措施；方法：采用系统回顾性方法，分析我院自1956年-2002年收治的高原肺水肿住院病例；结果：氨茶碱组、速尿组、硝苯吡啶组、酚妥拉明组、654-2组、高压氧组及NO组患者症状、体征、X线平片肺部阴影消失时间与基础治疗组比较，差异有显著性；地塞米松组同基础治疗组相比无统计学意义；各治疗组相比，氨茶碱组、NO组及速尿组的临床疗效明显优于其它治疗组；结论：综合比较各种药物、措施。现场救治HAPE临床疗效的优劣依次为：氨茶碱、NO、速尿、硝苯吡啶、酚妥拉明、高压氧等。     

高原肺水肿治疗前后血清心肌肌钙蛋白T的变化

目的 探讨诊断和判别高原肺水肿（ＨＡＰＥ）状态的新指标。方法 在海拔３７００ｍ处对８例ＨＡＰＥ患者在治疗前及临床治愈后分别测定血清肌酸激酶同功酶（ＣＫ－ＭＢ）和ｃＴｎＴ两项指标。结果 ＨＡＰＥ患者血清ＣＫ－ＭＢ和ｃＴｎＴ临床治愈后较治疗前均降低,二者间的差别有非常显著性意义（Ｐ〈０．０１）。结论 ＨＡＰＥ时存在心肌损伤,血清ｃＴｎＴ是一项具有高灵敏度、高特异性的血清心肌损伤标志物,对ＨＡＰＥ的诊断、病情分析有一定的价值。     

高原肺水肿的X线表现征象与发病时间和病理的关系

目的:分析35例高原肺水肿的X线表现征象,讨论与不同发病时间及病理改变的关系和意义。方法:西藏昌都地区平均海拔高度3 500m,昌都邦达机场平均海拔高度4 600m。35例中除1例外籍人士外均为汉族,第一次急进高原23例,再次重返高原12例。乘飞机首次抵海拔4 600m高原后不久发病16例,而再次重返高原中有3例。结果:高原肺水肿早期(发病第1天)X线表现征象:以肺纹理增多似间质型纤维化或支气管炎样改变、小斑片影或似絮状影改变为主,以右肺中下叶改变多;进展期(第2天~3天)呈多样特点,如小斑片影似絮状影、斑片影似有融合样改变、片影如蝶翼样其典型为蝴蝶状分布于两肺、弥漫状实变影;稳定期与恢复期(第4天~5天)与早期似有一定类似,如以小斑片影或似絮状影改变,肺纹理增多似间质型纤维化与支气管炎样改变为主。结论:高原肺水肿系综合因素结果,除低氧刺激使肺泡壁内毛细管超微结构改变与神经、体液调节紊乱外,高寒低温、上呼吸道感染与休息不佳等均有明显关系,高原肺水肿的X线表现不但与发病的时间有明显关系,也与病理改变联系密切。     

Acute medical problems in the Himalayas outside the setting of altitude sickness

Well-recognized medical threats at high altitude (>2,500 m) include acute mountain sickness (AMS), high altitude pulmonary edema (HAPE), and high altitude cerebral edema (HACE). Thousands of travelers in the Himalayas are exposed annually to these often life-threatening syndromes. Their recognition and treatment has advanced considerably in recent years. In the Himalayas, we frequently see acute medical problems outside the setting of AMS and the two types of altitude edemas. Many of these other conditions are also hypoxia related and sometimes may mimic the classic high altitude illnesses of AMS, HAPE, and HACE. Although the vast majority of these medical problems are neurological, pulmonary and other organ system dysfunction also occur. These "non-high altitude sickness" disease entities in persons who sojourn to remote mountainous environments are reviewed in this paper to enhance their recognition, diagnosis, and treatment.     

血常规、血气及血生化改变在高原肺水肿早期诊断中的意义

目的对血常规、血气及血生化改变在高原肺水肿（HAPE）早期诊断中的意义进行探讨。方法应用急性高原反应症状评分表,对24200例急进高原人员进行评分,筛选出高度疑似HAPE患者作为重点观察及随访对象,并给予卧床休息及吸氧。对所有重点观察及随访对象的血常规、血气及血生化（含电解质、肝功、肾功）变化情况进行检测分析。结果重点观察对象中,确诊HAPE组进入高原第1、2、3d的血白细胞总数（WBC）及中性粒细胞比率（N）均显著高于非HAPE组（P〈0．01）;两组血气结果比较,HAPE组氧分压（PaO2）、二氧化碳分压（PaCO2）、动脉血氧饱和度（SaO2）及氧合指数（FiO2／PaO2）在进入高原第1、2d均显著低于非HAPE组（P〈0．01）,HAPE组pH值显著高于非HAPE组（P〈0．01）;两组血生化比较,HAPE组除钾（K^＋）第2d显著低于非HAPE组外,各指标均无显著差异。结论早期白细胞计数增加及低氧血症持续性进行性加重与HAPE的发病有着密切的关系,加强疑似HAPE患者早期血常规及动脉血气的监测,有利于HAPE的早期诊断。     

高原性肺水肿88例影像分析

目的探讨高原性肺水肿(high altitude pulmonary edema,HAPE)患者的临床影像学特征及影像诊断价值。方法对88例HAPE患者临床影像学资料进行回顾性分析研究。结果 88例HAPE影像表现为单侧或双侧肺毛玻璃状、斑片状、片状影、肺门区团片状影、弥漫性实变影等,常合并出现,以右侧多见;肺门改变可正常或模糊、增大;可伴叶间裂增厚。结论影像检查是诊断HAPE的简捷可靠的诊断手段,尤其是X线平片可作为HAPE的首选检查,胸部CT检查可对其作出早期诊断并作为重要的补充检查手段。     

西宁地区高原性肺水肿27例临床分析

本文对中度海拔２２６０ｍ高原肺水肿２７例临床资料进行了分析，揭示了中度海拔高原肺水肿的临床，心电图，肺部Ｘ线的特点及发生，发展规律，结合文献对有关产进行了讨论。认为该病系由高原缺氧所致肺动脉高压，肺毛细血管通透性增加，肺血流量增多等综合因素所致，同时易感因素的存在，重返高原或进入高原速度较快在该病的发病过程中的重要作用。     

急性高山病患者血浆胰岛素、血糖含量的变化

本文观察了拉萨地区(海拔3658m)10名高原健康人及高原反应、高原肺水肿患者各8名,以及2例高原昏迷患者血浆胰岛素水平、血糖含量的变化。发现高原反应、高原肺水肿患者血糖较正常人高,2例高原昏迷患者血糖偏低。高原反应患者血浆胰岛素未有改变,而高原肺水肿、高原昏迷患者血浆胰岛素明显高于高原健康人。     

左旋精氨酸治疗高原肺水肿的临床研究

目的 :观察左旋精氨酸 (L -Arg)治疗高原肺水肿的临床效果。方法 :在海拔 370 0m ,静脉滴注L -Arg治疗高原肺水肿10例 ,雾化吸入L -Arg治疗 16例 ,并与吸入一氧化氮 (NO)混合气体治疗的 11例作对照。结果 :三组患者的肺部湿罗音消失时间和病程日数均无显著性差异 (P >0 .0 5 ) ,NO吸入组肺部x线阴影消失时间较L -Arg静脉注射组和L -Arg雾化吸入组缩短 ,差异非常显著 (P <0 .0 1)。结论 :静脉滴注和雾化吸入L -Arg治疗高原肺水肿疗效较好且经济、简便、无毒性 ,便于基层推广应用     

高原肺水肿的临床分型——附1200例病历分析

本文总结了1200例高原肺水肿临床资料,依照高原肺水肿的临床表现及治疗特征。提出了临床上较为实用的分型意见。