Pitman Justin T, Thapa Ghan B, Harris N Stuart
Department of Emergency Medicine, Massachusetts General Hospital, Boston, MA (Drs Pitman and Harris).
Mountain Medicine Society of Nepal, Maharajgunj, Kathmandu, Bagmati, Nepal (Dr Thapa).
Wilderness Environ Med. 2015 Sep;26(3):319-26. doi: 10.1016/j.wem.2015.02.008. Epub 2015 Apr 8.
To investigate whether ultrasonography can be used for field volume status assessment and to determine whether a detectable difference in intravascular volume exists in individuals with acute mountain sickness (AMS) compared with those without.
Study was performed at the Himalayan Rescue Association Clinic in Manang, Nepal, located on the Annapurna trekking circuit at an altitude of 3519 m (11545 feet). A convenience sample was taken from individuals trekking over 5 to 8 days from 760 m (2490 feet) to 3519 m (11,545 feet), comparing asymptomatic trekkers vs those who experienced AMS. Subjects were evaluated for AMS based on the Lake Louise AMS Questionnaire (LLS ≥ 3 indicates AMS). After medical screening examination, both groups (control, n = 51; AMS, n = 18) underwent ultrasonography to obtain measurements of inferior vena cava collapsibility index (IVC CI) and left ventricular outflow tract velocity-time integral (LVOT VTI) before and after a passive leg raise (PLR) maneuver.
There was no statistically significant difference between groups regarding change in heart rate before and after PLR, or IVC CI; however, there was a statistically significant greater increase in LVOT VTI after PLR maneuver in control group subjects compared with those with AMS (18.96% control vs 11.71% AMS; P < .01).
Ultrasonography is a useful tool in the assessment of intravascular volume at altitude. In this sample, we found ultrasonographic evidence that subjects with AMS have a higher intravascular volume than asymptomatic individuals. These data support the hypothesis that individuals with AMS have decreased altitude-related diuresis compared with asymptomatic individuals.
探讨超声检查是否可用于评估野外容量状态，并确定与未患急性高原病（AMS）的个体相比，患 AMS 的个体血管内容量是否存在可检测到的差异。
研究在尼泊尔马囊的喜马拉雅救援协会诊所进行，该诊所位于安纳布尔纳徒步线路上，海拔 3519 米（11545 英尺）。从徒步 5 至 8 天、海拔从 760 米（2490 英尺）上升至 3519 米（11545 英尺）的个体中选取便利样本，比较无症状徒步者与患 AMS 的徒步者。根据路易斯湖 AMS 问卷对受试者进行 AMS 评估（LLS≥3 表示 AMS）。经过医学筛查检查后，两组（对照组，n = 51；AMS 组，n = 18）均接受超声检查，以获取被动抬腿（PLR）操作前后的下腔静脉塌陷指数（IVC CI）和左心室流出道速度时间积分（LVOT VTI）测量值。
两组在 PLR 前后心率变化或 IVC CI 方面无统计学显著差异；然而，与 AMS 组相比，对照组受试者在 PLR 操作后 LVOT VTI 的增加在统计学上显著更大（对照组为 18.96%，AMS 组为 11.71%；P <.01）。
超声检查是评估高原血管内容量的有用工具。在该样本中，我们发现超声证据表明患 AMS 的受试者血管内容量高于无症状个体。这些数据支持以下假设：与无症状个体相比，患 AMS 的个体与海拔相关的利尿作用减弱。
