Kellum J A, Kramer D J, Pinsky M R
Department of Anesthesiology/CCM, University of Pittsburgh Medical Center, PA 15213-2582, USA.
J Crit Care. 1995 Jun;10(2):51-5. doi: 10.1016/0883-9441(95)90016-0.
This paper describes the calculation of the strong ion gap (SIG), a physical chemical methodology similar to the anion gap (AG), as a measure of the anion/cation balance exclusive of sodium, potassium, chloride, and bicarbonate. We compared the SIG and AG methodologies in three groups of subjects with and without unexplained anions. These groups were (1) healthy volunteers with hyperlacticemia during exercise; (2) intensive care unit (ICU) patients with sepsis; and (3) ICU patients with severe liver disease.
The SIG, AG, and corrected AG (AGc) were calculated for each group from data available in the original reports (groups 1 and 2) and by retrospective chart review (group 3).
The SIG correlated poorly with the AG in group 2, whereas no correlation was seen in groups 1 and 3. The AGc correlated with SIG in all three groups (r = .99, .93, and .91 respectively; P < .01 for each group). Although the AG was similar, the SIG differed for each group. Group 1 had levels of SIG near zero, and groups 2 and 3 had mean SIG's of 4.80 +/- 4.67 mEq/L and 9.60 +/- 6.43 mEq/L respectively. The composition of the anion gap differed markedly among subject types.
The SIG correlates with the AG once corrected for all known anions. The SIG technique can detect unknown anions in a patient population known to have them and does not detect unknown anions in healthy volunteers during exercise. This test detects large amounts of unknown anions in some patients with sepsis or liver disease. Therefore, the test is both sensitive and specific in characterizing metabolic acidosis.
本文描述了强离子间隙（SIG）的计算方法，这是一种类似于阴离子间隙（AG）的物理化学方法，用于衡量排除钠、钾、氯和碳酸氢盐后的阴离子/阳离子平衡。我们在三组有或无不明阴离子的受试者中比较了SIG和AG方法。这三组分别是：（1）运动期间伴有高乳酸血症的健康志愿者；（2）患有败血症的重症监护病房（ICU）患者；（3）患有严重肝病的ICU患者。
根据原始报告中的可用数据（第1组和第2组）以及通过回顾性病历审查（第3组），计算每组的SIG、AG和校正后的AG（AGc）。
第2组中SIG与AG的相关性较差，而第1组和第3组中未观察到相关性。所有三组中AGc与SIG均相关（分别为r = 0.99、0.93和0.91；每组P < 0.01）。尽管AG相似，但每组的SIG不同。第1组的SIG水平接近零，第2组和第3组的平均SIG分别为4.80±4.67 mEq/L和9.60±6.43 mEq/L。阴离子间隙的组成在不同受试者类型之间有显著差异。
一旦对所有已知阴离子进行校正，SIG与AG相关。SIG技术可以在已知存在不明阴离子的患者群体中检测到它们，而在运动期间的健康志愿者中未检测到不明阴离子。该测试在一些败血症或肝病患者中检测到大量不明阴离子。因此，该测试在表征代谢性酸中毒方面既敏感又特异。
