This prospective, randomized, blinded, interventional cross-over study investigated the distribution, elimination, plasma volume expansion, half-life, comparative potency, and ideal fluid prescription of three commonly prescribed intravenous (IV) fluids in 10 healthy conscious cats using volume kinetic analysis that is novel to veterinary medicine. Each cat received 20 mL/kg of balanced isotonic crystalloid (PLA), 3.3 mL/kg of 5% hypertonic saline (HS), and 5 mL/kg of 6% tetrastarch 130/0.4 (HES) over 15 min on separate occasions. Hemoglobin concentration, red blood cell count, hematocrit, heart rate, and blood pressure were measured at baseline, 5, 10, 15, 20, 30, 40, 50, 60, and every 15 min until 180 min. Urine output was estimated every 30 min using point-of-care bladder ultrasonography. Plasma dilution derived from serial hemoglobin concentration and red blood cell count served as input variables for group and individual fluid volume kinetic analyses using a non-linear mixed effects model. In general, the distribution of all IV fluids was rapid, while elimination was slow. The half-lives of PLA, HS, and HES were 49, 319, and 104 min, respectively. The prescribed fluid doses for PLA, HS, and HES resulted in similar peak plasma volume expansion of 27–30% potency of HS was 6 times higher than PLA and 1.7 times greater than HES, while HES was 3.5 times more potent than PLA. Simulation of ideal fluid prescriptions to achieve and maintain 15 or 30% plasma volume expansion revealed the importance of a substantial reduction in infusion rates following initial IV fluid bolus. In conclusion, volume kinetic analysis is a feasible research tool that can provide data on IV fluid kinetics and body water physiology in cats. The rapid distribution but slow elimination of IV fluids in healthy conscious cats is consistent with anecdotal reports of fluid overload susceptibility in cats and warrants further investigation.

这项前瞻性，随机，盲，干预性交叉研究使用体积动力学研究了三种常见处方静脉（IV）液在10只健康清醒猫中的分布，消除，血浆容量膨胀，半衰期，相对效价和理想液剂。对兽医学来说是新颖的分析。每只猫分别在15分钟内分别接受20 mL / kg的平衡等渗晶体（PLA），3.3 mL / kg的5％高渗盐水（HS）和5 mL / kg的6％四淀粉130 / 0.4（HES）。在基线，第5、10、15、15、20、30、40、50、60和每15分钟至180分钟测量血红蛋白浓度，红细胞计数，血细胞比容，心率和血压。使用护理点膀胱超声检查每30分钟估计尿量。使用非线性混合效应模型，从系列血红蛋白浓度和红细胞计数得出的血浆稀释度用作组和个体体液量动力学分析的输入变量。通常，所有静脉输液的分布较快，而清除速度较慢。PLA，HS和HES的半衰期分别为49、319和104分钟。规定的PLA，HS和HES液体剂量导致血浆峰体积扩张类似，HS的效价为27-30％，比PLA高6倍，比HES高1.7倍，而HES比PLA高3.5倍。对达到和维持15％或30％血浆容量膨胀的理想液体处方的模拟显示了在初始IV液体推注后大幅降低输注速度的重要性。结论，体积动力学分析是一种可行的研究工具，可以提供有关猫的IV流体动力学和体内水分生理的数据。在健康的意识清晰的猫中快速分配但缓慢消除静脉输液与猫中液体超负荷敏感性的传闻相一致，值得进一步研究。