Diabetic ketoacidosis: difference between potassium determined by blood gas analysis versus plasma measurement

Abstract

OBJECTIVE: To evaluate the accuracy of potassium concentrations measured by blood gas analysis (PBG) compared with laboratory serum potassium (LSP), in the initial care of patients with diabetic ketoacidosis (DKA). SUBJECTS AND METHODS: Fifty three patients with diabetes mellitus were evaluated in a retrospective analysis. PBG was carried out using the Radiometer ABL 700 (Radiometer Copenhagen®), and results were compared with LSP ADVIA 1650 Chemistry system (Siemens®), the gold standard method. Both methods are based on potentiometry. RESULTS: Mean PBG was 3.66 mmol/L and mean LSP was 4.79 mmol/L. Mean difference between PBG and LSP was -1.13 mmol/L (p < 0.0005, 95% CI, -1.39 to -0,86). Lin concordance correlation coefficient was rc = 0.28 (95% CIb, 0.10 to 0.45), demonstrating low concordance between the methods. CONCLUSION: Although PBG measurement is faster and easier, it should not be used as a surrogate for LSP in the clinical treatment of DKA.

<p>Correlation of acidosis-adjusted potassium level and cardiovascular outcomes in diabetic ketoacidosis: a systematic review</p>

“…In terms of quality of the studies, 22 studies31–39,41,42,44,46,49,52–54,56,58,59,61,71 scored poor, 18 studies9,16,21,45,47,48,50,51,60,62,63,66,68–70,72–74 scored fair, and two studies64,65 scored good on NOS. Among studies scoring 5, four 43,55,62,72 were scored on the basis of comparability by controlling confounding factors between the groups as well.…”

“…Of the total 47 research articles, 249,21,33,39,45,47–49,51–53,56,58–60,62–64,68–71,73,74 were cross-sectional case series mainly describing retrospective data on either prevalence or simple characteristics of DKA patients upon admission (Table 1). Two of the studies38,65 were cohorts of DKA patients further divided on the basis of treatment intervention given at a given time and retrospectively evaluated for the efficacy or safety of the said treatment intervention.…”

“…The corresponding values for actual potassium level and pH of mentioned values was 3.4 mmol/L with a pH of 7.19,56 and 5.6 with a pH of 7.14 40. Thirteen included studies38,39,41,42,51,53,60,64,65,67,68,70 calculated the value of potassium to be equal or below 3.5 mmol/L when the patients sought medical advice; out of these, only one study56 reported the average actual potassium level to be lower than 3.5 mmol/L. Upon distributing the countries on the basis of their region, it was notable that the least potassium level was seen in mid-Eastern countries (4.4 mmol/L); the minimum pH was observed in the far-Western region (7.11); and the maximum number of patient data originated from mid-Western countries (patient number = 1,995).…”

“…However, such normo- or hyper-kalemia was deceiving in nature as there were 13 studies38,39,41,42,51,53,56,60,64,65,67,68,70 which had a corrected potassium level below 3.5 mmol/L. Further findings of the current review were in line with an aforementioned hypothesis where, in five of the studies,38,41,56,60,64 pH-adjusted corrected potassium was as low to produce an adverse CV outcome resultant of hypokalemia 11,15. When these studies were analyzed for any reported CV event in correlation of potassium, only three of the studies38,39,51 reported such events; the results were, however, not in specificity to hypokalemia.…”

Can VBG analysis replace ABG analysis in emergency care?

“…Two studies have explored agreement between serum and blood gas potassium concentrations 7 8. In both, the serum concentration was usually higher than the blood gas concentration, but 95% limits of agreement were wide with up to 66% being outside ±0.5 mmmol/L.…”