血清阴离子间隙在危重新生儿代谢性酸中毒鉴别诊断中的应用

Serum anion gap in the differential diagnosis of metabolic acidosis in critically ill newborns.

作者信息

Lorenz J M, Kleinman L I, Markarian K, Oliver M, Fernandez J

机构信息

Department of Pediatrics and Human Development, Michigan State University, East Lansing, Michigan, USA.

出版信息

J Pediatr. 1999 Dec;135(6):751-5. doi: 10.1016/s0022-3476(99)70096-x.

DOI:10.1016/s0022-3476(99)70096-x

PMID:10586180

Abstract

OBJECTIVES

To determine in critically ill newborn infants (1) the range of the serum anion gap without metabolic acidosis and (2) whether the serum anion gap can be used to distinguish newborns with lactic acidosis from those with hyperchloremic metabolic acidosis.

STUDY DESIGN

Umbilical arterial blood gases and serum electrolyte and lactate concentrations were measured simultaneously in 210 samples from 63 infants over the first week of life. Metabolic acidosis was defined as a blood base deficit (BD) >4 mmol/L. The anion gap was calculated as [Na(+)] - [C1(-)] - [TCO (2)]. Lactic acidosis was defined as a serum lactate concentration >2 SD above the mean serum lactate concentration in samples without metabolic acidosis.

RESULTS

In 89 blood samples with BD <4 mmol/L, serum lactate concentration decreased with postnatal age (r = 0.51). The upper limit of serum lactate concentration was 3.8 mmol/L at less than 48 hours, 2.4 mmol/L between 48 and 96 hours, and 1.5 mmol/L for infants greater than 96 hours of age. The mean serum anion gap +/- 2 SD in 174 samples without lactic acidosis was 8 +/- 4 mmol/L; in 36 samples with lactic acidosis it was 16 +/- 9 mmol/L (P <.0001). Serum anion gap and lactate concentration were poorly correlated for samples without lactic acidosis (r = 0.04) but highly correlated in those with lactic acidosis (r = 0.81, P <.0001). None of the 85 samples with metabolic acidosis but without lactic acidosis had an anion gap >16 mmol/L; only 4 of 36 samples with lactic acidosis had an anion gap <8 meq/L. However, 25 of 36 samples with lactic acidosis had serum anion gaps of 8 to 16 mmol/L.

CONCLUSION

In the presence of metabolic acidosis, a serum anion gap >16 mmol/L is highly predictive of lactic acidosis; a serum anion gap <8 is highly predictive of the absence of lactic acidosis; an anion gap = 8 - 16 mmol/L has no use in the differential diagnosis of metabolic acidosis in the critically ill newborn.

摘要

目的

确定危重新生儿（1）无代谢性酸中毒时血清阴离子间隙的范围，以及（2）血清阴离子间隙是否可用于区分乳酸酸中毒新生儿与高氯性代谢性酸中毒新生儿。

研究设计

在出生后第一周内，对63例婴儿的210份样本同时测定脐动脉血气、血清电解质和乳酸浓度。代谢性酸中毒定义为血碱缺失（BD）>4 mmol/L。阴离子间隙计算为[Na⁺]-[Cl⁻]-[TCO₂]。乳酸酸中毒定义为血清乳酸浓度高于无代谢性酸中毒样本中血清乳酸浓度均值2个标准差。

结果

在89份BD<4 mmol/L的血样中，血清乳酸浓度随出生后年龄下降（r = 0.51）。出生后48小时内血清乳酸浓度上限为3.8 mmol/L，48至96小时为2.4 mmol/L，出生后96小时以上婴儿为1.5 mmol/L。174份无乳酸酸中毒样本的血清阴离子间隙均值±2个标准差为8±4 mmol/L；36份有乳酸酸中毒样本中为16±9 mmol/L（P<.0001）。无乳酸酸中毒样本中血清阴离子间隙与乳酸浓度相关性差（r = 0.04），但有乳酸酸中毒样本中两者高度相关（r = 0.81，P<.0001）。85份有代谢性酸中毒但无乳酸酸中毒的样本中，无一例阴离子间隙>16 mmol/L；36份有乳酸酸中毒的样本中，仅4例阴离子间隙<8 meq/L。然而，36份有乳酸酸中毒的样本中有25例血清阴离子间隙为8至16 mmol/L。