Hughes Fintan, Mythen Monty, Montgomery Hugh
Institute for Sport, Exercise and Health, University College London, 170 Tottenham Court Road, London, W1T 7HA UK.
Perioper Med (Lond). 2018 Jan 10;7:1. doi: 10.1186/s13741-017-0081-4. eCollection 2018.
Dehydration is highly prevalent and is associated with adverse cardiovascular and renal events. Clinical assessment of dehydration lacks sensitivity. Perhaps a patient's thirst can provide an accurate guide to fluid therapy. This systematic review examines the sensitivity of thirst in responding to changes in plasma osmolality in participants of any age with no condition directly effecting their sense of thirst.
Medline and EMBASE were searched up to June 2017. Inclusion criteria were all studies reporting the plasma osmolality threshold for the sensation of thirst.
A total of 12 trials were included that assessed thirst intensity on a visual analogue scale, as a function of plasma osmolality (pOsm), and employed linear regression to define the thirst threshold. This included 167 participants, both healthy controls and those with a range of pathologies, with a mean age of 41 (20-78) years.The value ±95% CI for the pOsm threshold for thirst sensation was found to be 285.23 ± 1.29 mOsm/kg. Above this threshold, thirst intensity as a function of pOsm had a mean ± SEM slope of 0.54 ± 0.07 cm/mOsm/kg. The mean ± 95% CI vasopressin release threshold was very similar to that of thirst, being 284.3 ± 0.71 mOsm/kg.Heterogeneity across studies can be accounted for by subtle variation in experimental protocol and data handling.
The thresholds for thirst activation and vasopressin release lie in the middle of the normal range of plasma osmolality. Thirst increases linearly as pOsm rises. Thus, osmotically balanced fluid administered as per a patient's sensation of thirst should result in a plasma osmolality within the normal range. This work received no funding.
脱水现象极为普遍，且与不良心血管及肾脏事件相关。对脱水的临床评估缺乏敏感性。或许患者的口渴感可为液体疗法提供准确指导。本系统评价旨在研究在无直接影响口渴感疾病的任何年龄参与者中，口渴感对血浆渗透压变化的反应敏感性。
检索截至2017年6月的Medline和EMBASE数据库。纳入标准为所有报告口渴感血浆渗透压阈值的研究。
共纳入12项试验，这些试验通过视觉模拟量表评估口渴强度，将其作为血浆渗透压（pOsm）的函数，并采用线性回归确定口渴阈值。其中包括167名参与者，既有健康对照者，也有患有一系列疾病的患者，平均年龄为41岁（20 - 78岁）。发现口渴感的pOsm阈值的数值±95%可信区间为285.23±1.29 mOsm/kg。高于此阈值时，口渴强度作为pOsm的函数，其平均±标准误斜率为0.54±0.07 cm/mOsm/kg。血管加压素释放阈值的平均±95%可信区间与口渴阈值非常相似，为284.3±0.71 mOsm/kg。研究间的异质性可通过实验方案和数据处理的细微差异来解释。
口渴激活和血管加压素释放的阈值处于血浆渗透压正常范围的中间。随着pOsm升高，口渴感呈线性增加。因此，根据患者的口渴感给予渗透压平衡的液体应能使血浆渗透压维持在正常范围内。本研究未获资助。
