Heileson Jeffery L, Jayne Julianna M
Army Medical Department Center and School, Health Readiness Center of Excellence, 3630 Stanley Road, JBSA-Fort Sam Houston, TX 78234.
Military Nutrition Division, US Army Research Institute of Environmental Medicine, 10 General Greene Ave., Natick, MA 01760.
Mil Med. 2019 Dec 1;184(11-12):e632-e636. doi: 10.1093/milmed/usz082.
Dehydration can have an immediate negative impact on the performance of Soldiers in training or combat environments. Field expedient methods for assessing hydration status may be valuable for service members. Measurement of urine-specific gravity (USG) via refractometer is inexpensive, simple, fast, and a validated indicator of hydration status. Manual (MAN) and digital (DIG) refractometers are commonly used in laboratory settings however, digital (DIG) devices have not been validated in the field against MAN devices. The purpose of this study was to determine the validity and feasibility of using a DIG refractometer to assess USG compared to a MAN refractometer during a military field training exercise.
Fifty-six military service members provided 672 urine samples during two 10-day field training exercises in central Texas. USG was assessed using a MAN and a DIG refractometer with cutoff value of ≥1.020 indicating hypohydration. The study received a non-human research determination.
The MAN measurements were strongly correlated with the DIG (r = 0.91, p < 0.0001) measurements. Bland-Altman analysis demonstrated agreement between the refractometers. The DIG displayed good sensitivity (93.9%) and specificity (85.8%) compared to the MAN.
The DIG refractometer used in this study was reliable and valid compared with a MAN device and was feasible for use in a field environment; however, the DIG refractometer tended to over overestimate hypohydration.
脱水会对处于训练或战斗环境中的士兵的表现立即产生负面影响。评估水合状态的现场简便方法对军人可能很有价值。通过折射仪测量尿比重（USG）成本低、操作简单、速度快，且是水合状态的有效指标。手动（MAN）和数字（DIG）折射仪通常用于实验室环境，然而，数字（DIG）设备尚未在现场与手动（MAN）设备进行有效性验证。本研究的目的是确定在军事野外训练演习期间，与手动折射仪相比，使用数字折射仪评估尿比重的有效性和可行性。
56名军人在德克萨斯州中部的两次为期10天的野外训练演习中提供了672份尿液样本。使用手动和数字折射仪评估尿比重，临界值≥1.020表示水合不足。该研究获得了非人体研究认定。
手动测量值与数字测量值高度相关（r = 0.91，p < 0.0001）。Bland-Altman分析表明折射仪之间具有一致性。与手动折射仪相比，数字折射仪显示出良好的敏感性（93.9%）和特异性（85.8%）。
本研究中使用的数字折射仪与手动设备相比可靠且有效，并且在野外环境中使用是可行的；然而，数字折射仪往往会高估水合不足的情况。
