野外與登山醫學----13---WMS 2019 update AMS/HACE Treatment Supplemental oxygen 13

Wilderness Medical Society Clinical Practice Guidelines for the Prevention and Treatment of Acute Altitude Illness: 2019 Update
統一名詞翻譯
AMS 急性高山病
HACE 高海拔腦水腫
acute altitude illness 急性高海拔疾病

Supplemental oxygen
Oxygen delivered by nasal cannula or mask at flow rates sufficient to relieve symptoms provides a suitable alternative to descent. A peripheral capillary oxygen saturation (SpO2) >90% is usually adequate. Use of oxygen is not required in all circumstances and is generally reserved for mountain clinics and hospitals where supply is abundant. It should also be used when descent is recommended but not feasible or during descent in severely ill individuals. The inspired oxygen fraction will vary significantly between oxygen delivery systems, including nasal cannula, simple facemasks, Venturi masks, or non-rebreather masks. In addition, because of interindividual variability in inspiratory flow rates and minute ventilation, the inspired fractional concentration of oxygen (FIO2) can vary significantly between patients for any given common oxygen delivery system, with the exception of high flow systems. For this reason, supplemental oxygen should be administered to target an SpO2 of >90% rather than a specific FIO2. Oxygen supply may be limited at remote high altitude clinics or on expeditions, necessitating judicious use. Short-term oxygen use in the form of visits to oxygen bars or use of over-the-counter oxygen canisters has not been studied for AMS treatment and should not be relied on for this purpose.

Recommendation. When available, ongoing supplemental oxygen sufficient to raise SpO2 to >90% or to relieve symptoms can be used while waiting to initiate descent or when descent is not practical. Recommendation Grade: 1A

野外與登山醫學----12---WMS 2019 update AMS/HACE Treatment Descent 12

Wilderness Medical Society Clinical Practice Guidelines for the Prevention and Treatment of Acute Altitude Illness: 2019 Update
統一名詞翻譯
AMS 急性高山病
HACE 高海拔腦水腫
acute altitude illness 急性高海拔疾病

TREATMENT Potential therapeutic options for AMS and HACE include the following.

Descent
Descent remains the single best treatment for AMS and HACE, but it is not necessary in all circumstances (discussed further later in the text). Individuals should descend until symptoms resolve unless terrain, weather, or injuries make descent impossible. Symptoms typically resolve after descent of 300 to 1000 m, but the required decrease in altitude varies among individuals. Individuals should not descend alone, particularly if they are experiencing HACE. Recommendation. Descent is effective for any degree of AMS/HACE and is indicated for individuals with severe AMS, AMS that fails to resolve with other measures, or HACE. Recommendation Grade: 1A

野外與登山醫學----11--WMS 2019 update AMS/HACE prevention suggested approach 11

Wilderness Medical Society Clinical Practice Guidelines for the Prevention and Treatment of Acute Altitude Illness: 2019 Update
統一名詞翻譯
AMS 急性高山病
HACE 高海拔腦水腫
acute altitude illness 急性高海拔疾病

SUGGESTED APPROACH TO AMS/HACE PREVENTION 預防AMS/HACE 建議策略
個人之間高度適應的速率, 高海拔生理反應差異很大. 臨床醫師要認知到, 通常有效的預防方式也無法完全避免 AMS/HACE, 這些策略僅是風險狀況的其中一種功能.
Because the rates of acclimatization and physiologic responses to high altitude vary considerably between individuals, clinicians must recognize that the recommendations that follow, although generally effective, do 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).

1. 第一個原則是確保逐漸上升至目標海拔, 旅行者可選擇在中海拔地區住一晚.
The first priority should be ensuring gradual ascent to the target elevation. Travelers can lower their risk by sleeping 1 night at an intermediate altitude. For example, sea-level residents traveling to Colorado resort areas over 2800 m can spend 1 night in Denver (1600 m). It should be recognized that a large number of people will travel directly by car or plane to commonly visited mountain high altitude locations, often located between 2500 and 3000 m, and may be unable to ascend gradually because of various logistical factors. In such situations, pharmacologic prophylaxis can be considered. Such individuals should also take care to slow the rate of further ascent beyond the altitude achieved at the start of their visit. With travel above 3000 m, individuals should not increase their sleeping elevation by more than 500 m$d-1 and should include a rest day (ie, no ascent to higher sleeping elevation) every 3 to 4 d. The increase in sleeping elevation should be less than 500 m for any given day of a trip. In many areas, terrain and other logistical factors prevent strict adherence to this approach and mandate larger gains in sleeping elevation over a single day. In such cases, acclimatization days should be strongly considered before and/or after these large gains in elevation and elsewhere in the itinerary to ensuredat the very least and as an approximation of properly controlled ascentdthat the overall ascent rate averaged over the entire trip (ie, total elevation gain divided by the number of days of ascent during the trip) is below the 500 m$d-1threshold.
Prophylactic medications are not necessary in low-risk situations but should be considered in addition to gradual ascent for use in moderate- to high-risk situations (Table 2). Acetazolamide is the preferred medication; dexamethasone may be used as an alternative in individuals with a history of intolerance of or allergic reaction to acetazolamide. In rare circumstances (eg, military or rescue teams that must ascend rapidly to and perform physical work at >3500 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 very rapid ascent. Acetazolamide and dexamethasone should be started the day before ascent but 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 d at the highest altitude. Individuals ascending faster than the recommended ascent rates may consider continuing preventive medication for 2 to 4 d after arrival at the target altitude, but there are no data to support this approach. For individuals ascending to a high point and then descending toward the trailhead (eg, descending from the summit of Mt. Kilimanjaro), in the absence of AMS/HACE symptoms, preventive medications should be stopped when descent is initiated.

野外與登山醫學----10---WMS 2019 update AMS/HACE prevention others 10

Wilderness Medical Society Clinical Practice Guidelines for the Prevention and Treatment of Acute Altitude Illness: 2019 Update

統一名詞翻譯
AMS 急性高山病
HACE 高海拔腦水腫
acute altitude illness 急性高海拔疾病

Other options 其他預防AMS/HACE 的方法

安地斯山的旅客有咀嚼可可葉, 喝可可茶. 及其他可可製品, 以預防AMS的傳統, 這些預防高海拔疾病的方式到底有多大功效, 目前尚缺乏適當的研究, 因此不建議用這種方式代替已經有實證研究的預防方式.
Chewed coca leaves, coca tea, and other coca-derived products are commonly recommended for travelers in the Andes mountains for AMS prevention. Their utility in prevention of altitude illness has not been properly studied, so they should not be substituted for other established preventive measures described in these guidelines.

其他預防方式也被廣泛研究, 包括抗氧化劑, 鐵, 膳食硝酸鹽, 白三烯受體阻斷劑, 磷酸二酯酶抑制劑, 水楊酸, 保鉀利尿劑 spironolactone. 英明格(註) 都被拿來試驗是否可以預防AMS, 但以上全部直到目前並無證據支持可以預防 AMS

Multiple studies have sought to determine whether other agents, including antioxidants,58 iron,59 dietary nitrates,60 leukotriene receptor blockers,61,62 phosphodiesterase inhibitors,63 salicylic acid,64 spironolactone,65 and sumatriptan can prevent AMS, but the current state of evidence does not support their use. 

強迫喝水, 過量喝水, 從來都不能預防高海拔疾病, 且可能造成低血鈉. 低血鈉與AMS症狀又有點相似. 

“Forced” or “over” hydration has never been found to prevent altitude illness and might increase the risk of hyponatremia; however, maintenance of adequate hydration is important because symptoms of dehydration can mimic those of AMS. 

夜間呼氣正壓可藉由一次使用的鼻夾達成, 對於預防AMS並無效果, 且這種方式可能造成遠端缺血, 

Nocturnal expiratory positive airway pressure (EPAP) administered via a single-use nasal strip during sleep is not effective for AMS prophylaxis,67 nor is a regimen of remote ischemic preconditioning.68 

雖然沒有研究檢視短期使用氧氣, 例如去氧氣吧台, 或使用小型氧氣瓶, 這些設備的容量僅 2-10 公升, 且使用時間很短暫, 不太可能預防AMS/HACE. 

No studies have examined short-term oxygen use in the form of either visits to oxygen bars or over-the-counter oxygen delivery systems by which individuals inhale oxygenenriched gas from a small prefilled canister. Due to the small volume of gas (2 to 10 L/canister) and short duration of administration, these interventions are unlikely to be of benefit and, as a result, have no role in AMS/HACE prevention. Other over-the-counter products, such as powdered drink mixes, also lack any evidence of benefit.


註: sumatriptan 是一種選擇性血清張力素(serotonin)催動劑, 商品名︰英明格

野外與登山醫學----09-Acute altitude illness WMS 2019 update AMS/HACE prevention Hypoxic tents 9

Wilderness Medical Society Clinical Practice Guidelines for the Prevention and Treatment of Acute Altitude Illness: 2019 Update
統一名詞翻譯
AMS 急性高山病
HACE 高海拔腦水腫
acute altitude illness 急性高海拔疾病

文章太長. 把最下面結論貼上來
建議: 低氧帳經過長期規則恰當的暴露周數後, 如果睡眠品質不受影響, 可用於加速高度適應, 預防AMS,
Recommendation. Hypoxic tents can be used for facilitating acclimatization and preventing AMS, provided sufficiently long exposures can be undertaken regularly over an appropriate number of weeks and other factors, such as sleep quality, are not compromised.

Recommendation Grade: 2B

低氧帳 Hypoxic tents

在計畫去高海拔前, 目前有很多商品可以提供個人在低氧環境睡覺或運動, 目前僅有一個安慰劑對照實驗, 評估這種方法是否有效. 這項實驗顯示在模擬高海拔環境睡覺的人, 相較於正常氣壓,  AMS 發生率降低 . 但這個系統技術上的難關, 導致參加研究的人無法接收完整的低氧劑量. 雖然這項系統已經商業化, 廣泛使用於登山家及高海拔地區參賽的運動員, 但沒有任何資料證明能提高登頂的成功率, 或改善體能

Commercial products are available that allow individuals to sleep or exercise in hypoxic conditions for the purpose of facilitating acclimatization before a trip to high altitude. Only 1 placebo-controlled study has examined their utility.57 Although this study demonstrated a lower incidence of AMS in persons who slept in simulated high altitude conditions compared to normoxia, technical difficulties with the system resulted in a substantial number of study participants not receiving the intended hypoxic dose. Although the systems are marketed to be of benefit and anecdotal reports suggest they are widely used by climbers and other athletes competing at high altitude, there are no data indicating increased likelihood of summit success or improved physical performance.

就像上面提到的高度適應方式, 藉由這套系統能累積的效益, 需要長時間暴露於低氧 (每天8小時以上) 持續數周,  短期漸歇性暴露於低氧, 包括運動訓練, 可能無助益
As with the preacclimatization approaches previously described, any benefit that may accrue 積累 from these systems is more likely with long hypoxic exposures (>8 h per day) for at least several weeks before planned high altitude travel. Short and/or infrequent exposures, including exercise training, are likely of no benefit.

除了系統的費用及運轉時所需電力, 個人會面對睡眠不佳的風險, 經過長時間睡眠不佳. 在競賽的時候表現可能更差.
In addition to the cost of the systems and power needed to run them, individuals face the risk of poor sleep, which over a long period of time could have deleterious effects on performance during an expedition.

建議: 低氧帳經過長期規則恰當的暴露周數後, 如果睡眠品質不受影響, 可用於加速高度適應, 預防AMS,
Recommendation. Hypoxic tents can be used for facilitating acclimatization and preventing AMS, provided sufficiently long exposures can be undertaken regularly over an appropriate number of weeks and other factors, such as sleep quality, are not compromised.

Recommendation Grade: 2B

野外與登山醫學--08--Acute altitude illness WMS 2019 update AMS/HACE prevention Staged ascent and preacclimatization 8

Wilderness Medical Society Clinical Practice Guidelines for the Prevention and Treatment of Acute Altitude Illness: 2019 Update
統一名詞翻譯
AMS 急性高山病
HACE 高海拔腦水腫
acute altitude illness 急性高海拔疾病

Staged ascent and preacclimatization 分段上升及高度適應

在爬到最高海拔前, 第六天至第七天, 停留於海拔 2200~3000 公尺, 可減少AMS 風險, 增加通氣量及氧和, 也可弱化肺動脈對於接下來高海拔 (4300 公尺) 的反應.

Two studies showed that spending 6 to 7 d at moderate altitude (~2200 to 3000 m) before proceeding to higher altitude (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 4300 m.16,48

有些遊客在前往高海拔前, 會先至海拔 2500-3000 公尺的高山旅館短時間停留. 海拔上升 1500 公尺的短暫停留以預防接下來更高海拔的AMS機率, 從生理角度看起來似乎還蠻合理的.
Many travelers to high altitude visit mountain resorts at more moderate elevations between 2500 and 3000 m. The value of short stays at intermediate elevations of ~1500 m for decreasing the risk of AMS during such ascents makes sense from a physiologic standpoint.

這種高度適應的策略並沒有人做過隨機研究, 雖然之前有研究顯示, 在海拔 1600 公尺處住一晚, 接下來前往海拔 1920-2950 公尺的地區, 可降低AMS機率.
However, this approach has not been studied in a randomized fashion, aside from 1 cross-sectional study finding a decreased risk of AMS in travelers who spent 1 night at 1600 m before ascent to resort communities between 1920 and 2950 m.5

很多研究評估,  在數天至數周內, 反覆暴露於低壓或常壓低氧環境, 這種方式稱為高度適應, 其結果並不一致, 有些研究說可以降低AMS發生率 或是嚴重度, 其他的研究卻顯示無效.
A larger number of studies examining the effects of repeated exposures to hypobaric or normobaric hypoxia in the days and week preceding high altitude travel (referred to as “preacclimatization”) showed mixed results, with some studies finding benefit in terms of decreased AMS incidence or severity49e51 and others showing no effect.52e55

在解讀這些高度適應研究時, 最大的困難是各自的低氧協議不同. 也不是每個研究都有證據顯示, 在這樣的低氧對於生理帶來哪些與高度適應符合的變化,.
A significant challenge in interpreting the literature on preacclimatization is the variability among the hypoxic exposure protocols used, as well as the fact that not all studies include evidence that their protocols induced physiologic responses consistent with acclimatization.

不管是分段上升或是高度適應, 對於多數高海拔的旅客都是很難做到的,
一般說來, 短時間 15-60 分鐘暴露於低氧, 或是在爬升前, 花幾次幾小時的時間暴露於低氧, 對於高度適應可能無用. 長時間(每天8小時, 連續七天) 暴露於低氧, 對於高度適應比較可能有幫助.

Implementation of either staged ascent or preacclimatization may be logistically difficult for many high altitude travelers. In general, short-term exposures (eg, 15 to 60 min of exposure to hypoxia, or a few hours of hypoxia a few times before ascent) are unlikely to aid acclimatization, whereas longer exposures (eg, >8 h daily for >7 d) are more likely to yield benefit.

低壓低氧相較於常壓低氧, 更能有效加速高度適應, 預防AMS. 但目前對於高度適應和分段上升最好的操作方式, 並沒有被徹底檢驗過, 因此專家會議建議, 可考慮這些方式, 但不贊同哪一種協議
Hypobaric hypoxia is more effective than normobaric hypoxia in facilitating preacclimatization and preventing AMS.56 Because the optimal methods for preacclimatization and staged ascent have not been fully determined, the panel recommends consideration of these approaches but does not endorse a particular protocol.

建議: 如果情況許可, 可考慮使用分段上升及高度適應, 來預防 AMS
Recommendation. When feasible, staged ascent and preacclimatization can be considered as a means for AMS prevention.
Recommendation Grade: 1C

野外與登山醫學----07-Acute altitude illness WMS 2019 update AMS/HACE prevention Acetaminophen 7

Wilderness Medical Society Clinical Practice Guidelines for the Prevention and Treatment of Acute Altitude Illness: 2019 Update
統一名詞翻譯
AMS 急性高山病
HACE 高海拔腦水腫
acute altitude illness 急性高海拔疾病
Acetaminophen 乙醯胺酚, 下面用比較多人知道的"普拿疼"代替

Acetaminophen 普拿疼

acetaminophen 通常劑量是 500 mg. 但一天吃的總量沒超過 4000mg 都還算安全
分析的對象是在海拔 4370 公尺至海拔 4940 公尺這一段的健行者, 給予普拿疼 每次 1000mg, 一天三次, 對於預防AMS效果與 ibuprofen 相近
但這篇研究並沒有安慰劑對照組, 研究團隊採用過去未接受治療的健行者的發生率作為比較, 並與之前的研究, 採用相同的上升速率.
依照這些研究報告, 不建議使用普拿疼做為預防AMS的藥物,
A single study demonstrated that acetaminophen 1000 mg 3 times daily was as effective as ibuprofen at preventing AMS in trekkers travelling between 4370 and 4940 m in elevation.45 Rather than including a placebo arm, the study attempted to establish the benefit of acetaminophen by comparing the incidence rates in the study with those of untreated trekkers from prior studies that used the same ascent profile. Based on these data, acetaminophen is not recommended for use as a preventive agent over acetazolamide or dexamethasone. Recommendation. Acetaminophen should not be used for AMS prevention. Recommendation Grade: 1C