Wilderness Medical Society Practice Guidelines for the Prevention and Treatment of Acute Altitude Illness: 2014 Update
因本文太長,所以切成幾次貼。這是第一節,AMS 及 HACE 的預防
1. 高山病及高海拔腦水腫預防 http://blog.xuite.net/ymmcc/twblog/540135871
2. 高山病及高海拔腦水腫治療 http://blog.xuite.net/ymmcc/twblog/540164931
3. 高海拔肺水腫預防 http://blog.xuite.net/ymmcc/twblog/540171169
4. 高海拔肺水腫治療 http://blog.xuite.net/ymmcc/twblog/540177927
5. 同時罹患HACE及HAPE的治療 http://blog.xuite.net/ymmcc/twblog/540188730
高海拔疾病的預防,不止針對絕對海拔在 2500 公尺以上發病,還要考慮之前過去在高海拔環境的表現,上升速率,能用於高度適應的天數
同樣的,診斷 AMS HACE HAPE 不要因為海拔低於 2500 公尺就直接排除。
同樣的,診斷 AMS HACE HAPE 不要因為海拔低於 2500 公尺就直接排除。
Altitude illness is more common above 2500 m but can be seen at lower elevations. As a result, preventive measures should be considered not only based on the altitude to which the individual is traveling but should also take into account factors such as the prior history of performance at high altitude, rate of ascent, and availability of rest days for acclimatization (described in greater detail below). Similarly, the diagnoses of AMS, HAPE, or HACE should not be excluded simply based on the fact that an individual is ill below 2500 m.
HACE 可視為最嚴重的 AMS 型態。
From a clinical standpoint, HACE represents an extreme form of AMS and, as a result, preventive and treatment measures for the 2 disorders can be addressed simultaneously.
From a clinical standpoint, HACE represents an extreme form of AMS and, as a result, preventive and treatment measures for the 2 disorders can be addressed simultaneously.
預防 AMS 及 HACE 的方法
1. 每天晚上睡眠的海拔,比當天實際上升的海拔影響更大
Gradual ascent Controlling the rate of ascent, in terms of the number of meters gained per day, is a highly effective means of preventing acute altitude illness; however, aside from 2 recent prospective studies,12,13 this strategy has largely been evaluated retrospectively.14 In planning the rate of ascent, the altitude at which someone sleeps is considered more important than the altitude reached during waking hours. Recommendation Grade: 1B.
Gradual ascent Controlling the rate of ascent, in terms of the number of meters gained per day, is a highly effective means of preventing acute altitude illness; however, aside from 2 recent prospective studies,12,13 this strategy has largely been evaluated retrospectively.14 In planning the rate of ascent, the altitude at which someone sleeps is considered more important than the altitude reached during waking hours. Recommendation Grade: 1B.
2. 丹木斯可預防 AMS,成人劑量,早上和晚上各吃 125 mg,或12小時吃一次,吃更多雖然也有預防效果,但副作用更大,且效益並沒有增加
兒童劑量每次吃 2.5mg/kg/dose,早晚各一次,或12小時吃一次,最大劑量同成人 125 mg.
Acetazolamide Multiple trials have established a role for acetazolamide in prevention of AMS.15–18 The recommended adult dose for prophylaxis is 125 mg twice daily (Table 1). Although doses up to 750 mg daily are effective at preventing AMS compared with placebo, they are associated with more frequent or increased side effects, do not convey greater efficacy, and, therefore, are not recommended for prevention. Recommendation Grade: 1A. The pediatric dose of acetazolamide is 2.5 mg/kg/dose (maximum 125 mg/dose) every 12 hours.19 Recommendation Grade: 1C.
3. 類固醇可預防 ams,成人劑量每次 2mg 六小時吃一次,或每次 4mg 每12小時吃一次
如果罹患 AMS 危險性更高的情況,例如軍隊或搜救隊需立即上升到海拔超過 3500 公尺的區域,可以吃更高劑量 每次 4mg 每 6 小時吃一次
如果罹患 AMS 危險性更高的情況,例如軍隊或搜救隊需立即上升到海拔超過 3500 公尺的區域,可以吃更高劑量 每次 4mg 每 6 小時吃一次
連續吃類固醇的時間不可以超過十天
小兒不建議使用類固醇預防AMS,建議緩慢提升海拔或吃 丹木斯
Dexamethasone Prospective trials have established a benefit for dexamethasone in AMS prevention.20,21 The recommended adult doses are 2 mg every 6 hours or 4 mg every 12 hours. Very high doses (4 mg every 6 hours) may be considered in very high-risk situations such as military or search and rescue personnel being airlifted to altitudes greater than 3500 m with immediate performance of physical activity but should not be used outside these limited circumstances. The duration of use should not exceed 10 days to prevent glucocorticoid toxicity or adrenal suppression. Recommendation Grade: 1A. Dexamethasone should not be used for prophylaxis in the pediatric population because of the potential for side effects unique to this population and the availability of other safe alternatives—specifically graded ascent and acetazolamide.
4. 銀杏效果有正有反,可能是銀杏的來源或組成的差異造成,丹木斯在預防AMS方面遠遠優於銀杏
Ginkgo biloba Although several trials have demonstrated a benefit of ginkgo in AMS prevention,22,23 several negative trials have also been published.24,25 This discrepancy may result from differences in the source and composition of the ginkgo products.26 Acetazolamide is considered far superior prophylaxis for AMS prevention. Recommendation Grade: 2C.
5. 止痛藥 ibuprofen 在兩篇文獻中也有預防 AMS 效果(比安慰劑有效),但沒有跟丹木斯比較其差異。只有在一篇文獻比較兩者差異,發現使用 ibuprofen 和丹木斯預防效果相當。至於 ibuprofen 與類固醇的差異尚未有文獻做比較。因為 ibuprofen 用於預防 ams 的臨床經驗尚未廣泛被記載,因此 ibuprofen 預防 AMS 的效果是否優於 丹木斯 和 類固醇尚未能給予建議。
Ibuprofen Two trials have demonstrated that ibuprofen (600 mg 3 times a day) is more effective than placebo at preventing AMS27,28; however, these trials did not include a comparison with acetazolamide. That comparison has been made in only a single other trial, which found equal incidence of high altitude headache and AMS between the 2 groups.29 No studies have compared ibuprofen with dexamethasone. Clinical experience with ibuprofen to prevent AMS is not extensively documented, so at this time ibuprofen cannot be recommended over acetazolamide and dexamethasone for AMS prevention. Recommendation Grade: 2B.
6. 提前做高度適應,分次上升。反覆接受低壓或常壓低氧的刺激,或先前至 2200-3000 公尺中海拔待 6-7 天,能降低 AMS 機率。改善通氣及氧和,減緩接下來上升到更高海拔對於肺部動脈壓的影響。但這種策略在實作上很困難,因為高度適應最佳方法尚未能定義。通常短期暴露不太能操作,例如在低氧環境 15-60 分鐘,或每次數小時,連續做幾次。 長時間(例如在 7 天以上,每天超過 8小時)更可能有效果
(分次上升 staged ascent 是指在中海拔 2200-3000 公尺 待 6-7 天)
Preacclimatization and staged ascent
Several studies have shown that repeated exposure to hypobaric or normobaric hypoxia in the time preceding a high altitude excursion (referred to as preacclimatization) or spending up to 6 to 7 days at a moderate altitude (approximately 2200–3000 m) before proceeding to higher altitudes (referred to as staged ascent) decreases the risk of AMS, improves ventilation and oxygenation, and blunts the pulmonary artery pressure response after subsequent ascent to higher altitudes.30–32 Implementation of such strategies may be logistically difficult. Because the optimal methods for preacclimatization and staged ascent have not been fully determined, the panel recommends consideration of these approaches, but cannot endorse a particular protocol regarding their implementation. In general, short-term exposures (eg, 15–60 minutes of exposure to hypoxia, or a few hours of hypoxia a few times before ascent) are unlikely to be of use, whereas longer exposures (eg, 8 h/d for 47 days) are more likely to yield benefit. Recommendation Grade: 1C.
7. 其他,在安地斯山脈常建議旅行者咀嚼 coca 葉子,喝可可茶,或吃其他 coca 做的產品來預防高海拔疾病,以上並沒有人去研究,這些方式不應該取代其他已經建構好的預防方法。其他藥物的研究也都無法預防AMS,強迫喝水,或過度喝水無法預防 AMS,且可能造成低血鈉,但維持足夠的水分是很重要的,因為脫水的症狀跟 AMS 相似。
Other options Chewed coca leaves, coca tea, and other coca-derived products are commonly recommended for travelers in the Andes for prophylaxis, and anecdotal reports suggest they are now being used by trekkers in Asia and Africa for similar purposes. Their utility in prevention of altitude illness has never been studied, however, and they should not be substituted for other established preventive measures described in these guidelines. Multiple studies have sought to determine whether other agents, including antioxidants, leukotriene receptor blockers, phosphodiesterase inhibitors, salicylic acid, spironolactone, and sumatriptan, can prevent AMS, but the current state of evidence does not support a role in AMS prevention for any of these agents. “Forced” or overhydration has also never been shown to prevent altitude illness and may even increase the risk of hyponatremia; however, maintenance of adequate hydration is important because symptoms of dehydration can mimic those of AMS.
總結 AMS 與 HACE 的預防
1. 低危險情況並不需要藥物預防,遵守不要上升太快的原則即可
2. 如果在海拔 3000 公尺以上活動,注意下列原則,每天睡覺的海拔不要超過 500 公尺上升,每 3-4 天需要有一天休息天,睡眠海拔維持相同高度,整個旅程的睡眠海拔不要超過每天 500 公尺。如果因不可抗力因素,單日需上升超過500公尺,建議在這個日子前後多加一天休息天,讓整個旅程每天平均上升在 500 公尺海拔閾值內
3. 在中等及高危險性的情況建議使用藥物預防,首選丹木斯,但對於丹木斯過敏或無法接受其副作用的人,可考慮類固醇 dexamethasone,這種高危險的情況還是盡量要避免
Suggested approach to AMS/HACE prevention
Because the physiologic responses to high altitude and rates of acclimatization vary considerably between individuals, clinicians must recognize that the recommendations that follow, although generally effective, will not guarantee successful prevention in all high altitude travelers. The approach to prevention of AMS and HACE should be a function of the risk profile of the individual traveling to high altitude (Table 2). In low-risk situations, prophylactic medications are not necessary and individuals should rely on a gradual ascent profile. Above an altitude of 3000 m, individuals should not increase the sleeping elevation by more than 500 m per day and should include a rest day (ie, no ascent to higher sleeping elevation) every 3 to 4 days. The increase in sleeping elevation should be less than 500 m for any given day of a trip. In many areas, terrain and other logistical factors often prevent strict adherence to this approach and mandate larger gains in sleeping elevation in a single day. In such cases, rest days should be strongly considered before or after such large gains in elevation and elsewhere in the itinerary to ensure that the overall ascent rate averaged over the entire trip (eg, total elevation gain divided by the number of days of ascent during the trip) falls below the 500 m/d threshold. Prophylactic medications should be considered in addition to gradual ascent for use in moderate-to-high risk situations. Acetazolamide is the preferred agent, but dexamethasone may be used as an alternative in individuals with prior history of intolerance of or allergic reaction to acetazolamide. In rare circumstances (eg, military or rescue teams who must ascend rapidly to and perform physical work 43500 m), consideration can be given to concurrent use of acetazolamide and dexamethasone. This strategy should be avoided except in these particular or other emergency circumstances that mandate a very rapid ascent.
丹木斯對於磺胺過敏的人有小概率會交叉反應,如果對磺胺過敏,建議在旅行之前可在醫師監督之下嘗試使用丹木斯。但如果因磺胺類藥物引起過敏性休克的患者就不要用丹木斯了。丹木斯和類固醇都要在上升之前就開始使用。但如果上升當天服用仍有效果,在相同高海拔停留數日之後,預防性使用藥物者,多用藥兩天可考慮停用。如果上升速率高於建議數值,建議在到達目標海拔後繼續吃滿四天
如果上升到最高海拔,開始下降的時候應該停用藥物
Acetazolamide carries a low risk of cross-reactivity in persons with sulfonamide allergy, but persons with known allergy to sulfonamide medications should consider a supervised trial of acetazolamide before the trip, particularly if planning travel into an area remote from medical resources.33 A history of anaphylaxis to sulfonamide medications should be considered a contraindication to acetazolamide. Acetazolamide and dexamethasone should be started the day before ascent (but will still have beneficial effects if started on the day of ascent). For individuals ascending to and staying at the same elevation for more than several days, prophylaxis may be stopped after 2 days at the target altitude. Individuals ascending faster than the recommended ascent rates should continue prophylaxis for a total of 4 days after arrival at the target altitude. Recommendation Grade: 2C. For individuals ascending to a high point and then descending toward the trailhead (eg, descending from the summit of Kilimanjaro), prophylactic medications should be stopped once descent is initiated.
低危險定義 Low
Individuals with no prior history of altitude illness and ascending to 小於等於 2800 m Individuals taking 大於等於 2 days to arrive at 2500–3000 m with subsequent increases in sleeping elevation 小於 500 m/d and an extra day for acclimatization every 1000 m
中度危險定義 Moderate
Individuals with prior history of AMS and ascending to 2500–2800 m in 1 day No history of AMS and ascending to 大於 2800 m in 1 day All individuals ascending 大於 500 m/d (increase in sleeping elevation) at altitudes above 3000 m but with an extra day for acclimatization every 1000 m
高危險定義 High
Individuals with a history of AMS and ascending to 大於 2800 m in 1 day All individuals with a prior history of HACE All individuals ascending to 大於 3500 m in 1 day All individuals ascending 大於 500 m/d (increase in sleeping elevation) above 大於 3000 m without extra days for acclimatization Very rapid ascents (eg, 小於 7-day ascents of Mt Kilimanjaro)
備註:AMS, acute mountain sickness; HACE, high altitude cerebral edema. Notes: Altitudes listed in the table refer to the altitude at which the person sleeps. Ascent is assumed to start from elevations o1200 m. The risk categories described above pertain to unacclimatized individuals.
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