| K+ Plasma Concentration (mmol/L) | Rate of K+ Supplementation (mEq/kg/hr) | K+ Recheck Frequency |
|---|---|---|
| 2-2.4 | 0.4-0.5 | Q2-4h |
| 2.5-2.9 | 0.3-0.4 | Q6-8h |
| 3-3.4 | 0.1-0.2 | Q12-24h |
| 3.5-4.5 | 0.05 | Q24h |
| >4.5-5 | Do not supplement |
About this calculator
This calculator is designed to help veterinarians calculate K+ supplementation in mEq/kg/hr (according to Table 1 recommendations) and then translate this value into how much potassium-containing solution you will add to a prespecified volume of IV fluids.
It is not recommended to exceed 0.5 mEq/kg/hr (K max), however there are some exceptions. In hypokalemic human patients and one veterinary case report, potassium infusion rates up to 0.7-0.9 mEq/kg/hr were used safely (Hamill et al. 1991; Allen et al. 2015). Careful mixing of potassium chloride after addition to flexible bags of fluids is extremely important; the rates above >0.5 mEq/kg/hr can be used ONLY in situations of life-threatening symptomatic hypokalemic when you don’t have time to supplement potassium slower or during CPR.
Patients receiving >0.1-0.2 mEq/kg/hr of K+ should have serum K+ monitored every 4-8 hours.
Patients receiving >0.4 mEq/kg/hr of K+ should receive constant ECG monitoring and serum K+ monitoring every 2-4 hours.
Important: Patients with hypokalemia caused by albuterol toxicity may require less potassium supplementation than recommended in Table 1 due to their transient nature of hypokalemia (caused by intracellular potassium shifting).
| Available K+ containing solutions (Additives) | Concentration of K+ per ml | Osmolarity | Recommended minimal dilution for peripheral administration |
|---|---|---|---|
| KCL 20mEq/10 ml | 2 mEq/ml | 4000 mOsm/L | 1:8 to 1:20 |
| KCL 10 mEq/50 ml | 0.2 mEq/ml | 400 mOsm/L | 1:1 to 1:3 |
| KCL 20 mEq/100ml | 0.2 mEq/ml | 400 mOsm/L | 1:1 to 1:3 |
| KCL 40 mEq/100 ml | 0.4 mEq/ml | 800 mOsm/L | 1:3 to 1:5 |
| KCL 4% | 0.53 mEq/ml | 1074 mOsm/L | 1:4 to 1:6 |
| KPhos | 4.4 mEq/ml of K+ and 3 mmol/ml of PO4- | 7400 mOsm/L | 1:20 to 1:40 |
| K2HPO4 (dipotassium phosphate) 174.2 mg/ml | 2 mEq/ml of K+ and 1 mmol/ml of HPO4- | 3000 mOsm/L | 1:5 to 1:10 |
References
1. Allen AE, Buckley GJ, Schaer M. Successful treatment of severe hypokalemia in a dog with acute kidney injury caused by leptospirosis. J Vet Emerg Crit Care (San Antonio). 2016 Nov;26(6):837-843. doi: 10.1111/vec.12416. Epub 2015 Dec 4. PMID: 26636549.
2. Hamill RJ, Robinson LM, Wexler HR, Moote C. Efficacy and safety of potassium infusion therapy in hypokalemic critically ill patients. Crit Care Med. 1991 May;19(5):694-9. doi: 10.1097/00003246-199105000-00016. PMID: 2026032.
3. Guida SJ, Bazzle L. Rebound hyperkalemia in a dog with albuterol toxicosis after cessation of potassium supplementation. J Vet Emerg Crit Care (San Antonio). 2023 Nov-Dec;33(6):715-721. doi: 10.1111/vec.13352. Epub 2023 Nov 9. PMID: 37943086.