Hypokalemia Estimated potassium requirements

Old Rule of Thumb

10 mEq of potassium is required for each 0.10 mEq/L drop in serum [K+]

Updated Rules

10 mEq of potassium (IV/ oral) is required for each 0.13 mEq/L (mean value for oral and IV). decline in serum [K+] from the target level.
.
IV:   10 meq --> 0.14 mEq/L mean change. Oral: 10 meq --> 0.12 mEq/L mean change.

Key Reference

Aboujamous H. et al. Evaluation of the Change in Serum Potassium Levels after Potassium Administration. J Clin Nephrol Ren Care 2016, 2:013.

• Every 10 mEq of potassium increased serum potassium 0.13 mEq/L. Similar dose responses were seen whether IV or PO potassium was administered.
• This study supports the common practice of administering 10 mEq of potassium for every 0.1 mEq/L desired increase in serum potassium.
• It takes a significant loss in potassium stores to see a drop in serum potassium level (i.e., the extracellular space) due to this large amount of potassium in the intracellular space that helps to compensate for any loss.
• Severe consequences of hypokalemia include cardiac arrhythmias, rhabdomyolysis, and muscle weakness that leads to respiratory depression or ileus. Chronic hypokalemia can cause increased ammoniagenesis, urinary concentration defects, polyuria, hypertension, acid base disorders, and hyperglycemia.
• In examining the effect of BMI on the level of potassium repletion achieved per 10 mEq of potassium administered, the intravenous group had an increase in serum potassium ranging from 0.10 to 0.17 mEq/L per 10 mEq administered while patients that received oral potassium had a change in potassium that ranged from 0.12 to 0.13 mEq/L per 10 mEq with no discernable pattern across different BMI classifications.
• The results further reveal that intravenous potassium appears to impact serum potassium levels similarly to the impact of oral potassium. Specifically, intravenous and oral potassium administration caused a mean 0.14 and 0.12 mEq/L increase in serum potassium level per 10 mEq administered, respectively.
• There is no data to suggest that the degree of baseline hypokalemia will exponentially increase the amount of repletion necessary. Therefore, the lack of representation of patients with baseline moderate or severe hypokalemia is not thought to be a limitation to allowing the results of the study to be applied to patients with all degrees of hypokalemia.