Open AccessPhysicochemical Approach to Determine the Mechanism for Acid–Base Disorders in 793 Hospitalized Foals
Author(s) -
Gomez D.E.,
Biermann N.M.,
Sanchez L.C.
Publication year - 2015
Publication title -
journal of veterinary internal medicine
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.356
H-Index - 103
eISSN - 1939-1676
pISSN - 0891-6640
DOI - 10.1111/jvim.13590
Subject(s) - anion gap , medicine , gastroenterology , receiver operating characteristic , horse , ion , area under the curve , electrolyte , endocrinology , acidosis , chemistry , biology , paleontology , organic chemistry , electrode
Background The quantitative effect of strong electrolytes, unmeasured strong anions ( UA s), p CO 2 , and plasma protein concentrations in determining plasma p H can be demonstrated using the physicochemical approach. Plasma anion gap ( AG ) and strong ion gap ( SIG ) are used to assess UA s in different species. Hypotheses Strong ions are a major factor influencing changes in plasma p H of hospitalized foals. AG and SIG accurately predict severe hyper‐ l ‐lactatemia ([ l ‐lac − ] > 7 mmol/L). Animals Seven hundred and ninety three hospitalized foals < 7 days old. Methods Retrospective study. The relationship between measured pH and physicochemical variables, and the relationship between plasma [ l ‐lac − ] and AG and SIG , were determined using regression analyses. Optimal AG and SIG cut points to predict hyper‐ l ‐lactatemia were identified using an ROC curve analysis. Results Combined, the measured strong ion difference and SIG accounted for 54–69% of the changes in the measured arterial pH of hospitalized foals. AG and SIG were significantly associated with plasma [ l ‐lac − ] ( P < .0001). The receiver operator characteristics ( ROC ) AUC of AG and SIG for prediction of severe hyper‐ l ‐lactatemia were 0.89 (95% CI , 0.8–0.95; P < .0001) and 0.90 (95% CI , 0.81–0.96; P < .0001), respectively. Severe hyper‐ l ‐lactatemia was best predicted by AG > 27 mmol/L (sensitivity 80%, 95% CI , 56–94, specificity 85%, 95% CI , 73–93; P < .0001) and SIG <−15 mmol/L (sensitivity 90%, 95% CI , 68–98; specificity 80%; 95% CI , 68–90; P < .0001). Conclusion and clinical relevance Altered concentrations of strong ions (Na + , K + , Cl − ) and UA s were the primary cause of acidemia of hospitalized foals. AG and SIG were good predictors of hyper‐ l ‐lactatemia and could be used as surrogate tests.