Tuyển tập các báo cáo nghiên cứu về y học được đăng trên tạp chí y học Critical Care giúp cho các bạn có thêm kiến thức về ngành y học đề tài: Unmeasured anions: the unknown unknowns. | Available online http content 12 1 113 Commentary Unmeasured anions the unknown unknowns Bala Venkatesh1 and Thomas J Morgan2 1 Department of Intensive Care Princess Alexandra and Wesley Hospitals University of Queensland Queensland QLD 4102 Australia 2Department of Intensive Care Mater Misericordiae Hospital South Brisbane Queensland QLD 4101 Australia Corresponding author Bala Venkatesh bala_venkatesh@ Published 5 February 2008 This article is online at http content 12 1 113 2008 BioMed Central Ltd Critical Care 2008 12 113 doi cc6768 See related research by Bruegger et al. http content 11 6 R130 Abstract Evidence is emerging that elevated concentrations of the intermediates of the citric acid cycle may contribute to unmeasured anions in critical illness. Both the anion gap and the strong ion gap are used as scanning tools for recognition of these anions. The mechanisms underlying these elevations and their significance require further clarification. Unmeasured ions have long captured the imagination of intensivists. Potential candidates include L-lactate p-hydroxy-butyrate D-lactate salicylate formate and oxalate in toxicological situations pyroglutamate semisynthetic penicillins sulphate and hippurate in renal failure and occasionally urate and amino acids with catabolic states and total parenteral nutrition. Reports of increased tricyclic acid TCA cycle anions in shock are now emerging 1 2 . Their presence is often inferred from the anion gap AG calculated as Na K - Cl- HCO3- . When its reference range is exceeded a search for unmeasured anions should commence irrespective of the overall metabolic acidbase status because a competing metabolic alkalosis can mask their presence. Likely culprits vary with the clinical scenario but the search usually starts with L-lactate and p-hydroxybutyrate. During this process stoichiometry is tracked between AAG measured AG - normal AG and the summed concentrations
