Innerhofer Nicole, Rajsic Sasa, Ronzani Marco, Breitkopf Robert, Gollmann Tepeköylü Can, Velik-Salchner Corinna, Schlosser Lisa, Fries Dietmar, Streif Werner, Schirmer Michael, Martini Judith
Department of Anesthesiology and Intensive Care Medicine, Medical University Innsbruck, 6020 Innsbruck, Austria.
Department for Cardiac Surgery, Medical University of Innsbruck, 6020 Innsbruck, Austria.
Diagnostics (Basel). 2023 Aug 4;13(15):2596. doi: 10.3390/diagnostics13152596.
Intraoperative fluid therapy is regularly used in patients undergoing cardiac surgery procedures with cardiopulmonary bypass (CPB). Although fluid administration has several advantages, it unavoidably leads to hemodilution. The hemodilution may further influence the interpretation of concentration-based laboratory parameters like hemoglobin (Hgb), platelet count (PLT) or prothrombin time (PT). These all parameters are commonly used to guide blood product substitution. To assess the impact of dilution on these values, we performed a prospective observational study in 174 patients undergoing elective cardiac surgery. We calculated the total blood volume according to Nadler's formula, and fluid therapy was correlated with a newly developed dilution coefficient formula at the end of CPB. Intravenously applied fluids were measured from the beginning of the anesthesia (baseline, T) and 15 min after the end of protamine infusion (end of CPB, T). The amount of the administered volume (crystalloids or colloids) was calculated according to the percentage of the intravascular fluid effect, and intraoperative diuresis was further subtracted. The median blood volume increased by 148% in all patients at T compared to the calculated total blood volume at T. This led to a dilution-dependent decrease of 38% in all three parameters (Hgb 24%, corrCoeff = 0.53; PLT 41%, corrCoeff = 0.68; PT 44%, corrCoeff = 0.54). The dilution-correlated decrease was significant for all parameters ( < 0.001), and the effect was independent from the duration of CPB. We conclude that the presented calculation-based approach could provide important information regarding actual laboratory parameters and may help in the guidance of the blood product substitution and potential transfusion thresholds. Further research on the impact of dilution and related decision-making for blood product substitution, including its impact on morbidity and mortality, is warranted.
术中液体治疗常用于接受体外循环（CPB）心脏手术的患者。尽管液体输注有诸多益处，但不可避免地会导致血液稀释。血液稀释可能会进一步影响基于浓度的实验室参数的解读，如血红蛋白（Hgb）、血小板计数（PLT）或凝血酶原时间（PT）。这些参数通常用于指导血液制品的替代。为评估稀释对这些值的影响，我们对174例接受择期心脏手术的患者进行了一项前瞻性观察研究。我们根据纳德勒公式计算总血容量，并在CPB结束时将液体治疗与新开发的稀释系数公式相关联。从麻醉开始（基线，T0）和鱼精蛋白输注结束后15分钟（CPB结束，T1）测量静脉输注的液体量。根据血管内液体效应的百分比计算输注量（晶体液或胶体液），并进一步减去术中尿量。与T0时计算的总血容量相比，所有患者在T1时的中位血容量增加了148%。这导致所有三个参数均出现与稀释相关的下降，下降幅度分别为38%（Hgb下降24%，相关系数=0.53；PLT下降41%，相关系数=0.68；PT下降44%，相关系数=0.54）。所有参数与稀释相关的下降均具有显著性（P<0.001），且该效应与CPB持续时间无关。我们得出结论，所提出的基于计算的方法可以提供有关实际实验室参数的重要信息，并可能有助于指导血液制品的替代和潜在的输血阈值。有必要进一步研究稀释对血液制品替代的影响以及相关决策，包括其对发病率和死亡率的影响。
