Department of Intensive Care Medicine, Jeroen Bosch Hospital, 's-Hertogenbosch, the Netherlands.
J Crit Care. 2013 Dec;28(6):1048-54. doi: 10.1016/j.jcrc.2013.06.005. Epub 2013 Jul 30.
This study aimed to describe Stewart parameters in critically ill patients with an apparently normal acid-base state and to determine the incidence of mixed metabolic acid-base disorders in these patients.
We conducted a prospective, observational multicenter study of 312 consecutive Dutch intensive care unit patients with normal pH (7.35 ≤ pH ≤ 7.45) on days 3 to 5. Apparent (SIDa) and effective strong ion difference (SIDe) and strong ion gap (SIG) were calculated from 3 consecutive arterial blood samples. Multivariate linear regression analysis was performed to analyze factors potentially associated with levels of SIDa and SIG.
A total of 137 patients (44%) were identified with an apparently normal acid-base state (normal pH and -2 < base excess < 2 and 35 < PaCO2 < 45 mm Hg). In this group, SIDa values were 36.6 ± 3.6 mEq/L, resulting from hyperchloremia (109 ± 4.6 mEq/L, sodium-chloride difference 30.0 ± 3.6 mEq/L); SIDe values were 33.5 ± 2.3 mEq/L, resulting from hypoalbuminemia (24.0 ± 6.2 g/L); and SIG values were 3.1 ± 3.1 mEq/L. During admission, base excess increased secondary to a decrease in SIG levels and, subsequently, an increase in SIDa levels. Levels of SIDa were associated with positive cation load, chloride load, and admission SIDa (multivariate r(2) = 0.40, P < .001). Levels of SIG were associated with kidney function, sepsis, and SIG levels at intensive care unit admission (multivariate r(2) = 0.28, P < .001).
Intensive care unit patients with an apparently normal acid-base state have an underlying mixed metabolic acid-base disorder characterized by acidifying effects of a low SIDa (caused by hyperchloremia) and high SIG combined with the alkalinizing effect of hypoalbuminemia.
本研究旨在描述在酸碱状态看似正常的危重病患者中的 Stewart 参数，并确定这些患者中混合代谢性酸碱紊乱的发生率。
我们进行了一项前瞻性、多中心研究，纳入了 312 例连续的荷兰重症监护病房患者，这些患者在第 3 至 5 天 pH 值正常（7.35 ≤ pH ≤ 7.45）。从 3 次连续动脉血样本中计算出表观（SIDa）和有效强离子差（SIDe）和强离子间隙（SIG）。采用多元线性回归分析来分析与 SIDa 和 SIG 水平相关的潜在因素。
共 137 例（44%）患者被确定为酸碱状态看似正常（正常 pH 值和-2 < 碱剩余 < 2 和 35 < PaCO2 < 45 mmHg）。在该组中，SIDa 值为 36.6 ± 3.6 mEq/L，这是由于高氯血症引起的（109 ± 4.6 mEq/L，氯化钠差值 30.0 ± 3.6 mEq/L）；SIDe 值为 33.5 ± 2.3 mEq/L，这是由于低白蛋白血症引起的（24.0 ± 6.2 g/L）；SIG 值为 3.1 ± 3.1 mEq/L。在住院期间，碱剩余增加是由于 SIG 水平降低和随后 SIDa 水平升高引起的。SIDa 水平与正离子负荷、氯负荷和入院时的 SIDa 水平相关（多元 r(2) = 0.40，P <.001）。SIG 水平与肾功能、脓毒症和重症监护病房入院时的 SIG 水平相关（多元 r(2) = 0.28，P <.001）。
酸碱状态看似正常的重症监护病房患者存在潜在的混合代谢性酸碱紊乱，其特征为低 SIDa（由高氯血症引起）和高 SIG 导致的酸化作用，以及低白蛋白血症引起的碱化作用。
