Hypokalemia is a pathophysiological state of serum potassium < 3.5 mmol/L. Potassium deficiency hypokalemia is often treated clinically by supplementing potassium chloride. Today, I will discuss three questions:
- What are the causes of potassium loss in patients with hypokalemia?
- How much mmol/L can 1 g potassium chloride raise blood potassium?
- When should intravenous potassium supplementation be administered? How much?
I. What are the causes of potassium loss in patients with hypokalemia? Patients with hypokalemia need detailed examination to identify the cause of potassium loss. Image source: “Practical Internal Medicine (15th Edition)”[2] span>2. How much mmol/L can 1 g potassium chloride increase blood potassium? Potassium chloride can be supplemented by oral and intravenous sources: (1) Mild hypokalemia (serum potassium 3.0-3.5 mmol/L): oral potassium supplementation; (2) Moderate to severe hypokalemia (serum potassium < 3.0 mmol/L) ), those who cannot take potassium supplements orally: intravenous potassium supplementation. After excluding daily dietary potassium intake and removing the cause of hypokalemia, the question “How much mmol/L can 1 g potassium chloride raise serum potassium?” should be based on oral and intravenous to discuss separately. 1. Oral potassium supplementation (1) 1 g potassium chloride tablet contains potassium 13.4 mmol
- K molar mass: 39 g/mol span>
- The molar mass of KCl: 74.5 g/mol
1 mol potassium and potassium chloride both contain 39 potassium g. And 1 g of potassium chloride contains 13.4 mmol of potassium, which is 0.52 g of potassium. (2) How much mmol/L can 1 g potassium increase blood potassium? For patients with mild hypokalemia, oral administration of 40-60 mmol potassium salts can increase serum potassium concentration by 1.0-1.5 mmol/L[1]. It can be concluded that a 1 g potassium chloride tablet (containing 13.4 mmol potassium) can raise serum potassium by about 0.27 mmol/L. 2. Intravenous potassium supplementation intravenous potassium supplementation The dosage is closely related to the severity of hypokalemia, clinical complications and other factors. It cannot be summed up with a simple formula. It is also impossible to infer how much mmol/L of potassium chloride injection (specification 10 mL: 1 g) can increase serum potassium. 3. When should intravenous potassium supplement be supplemented? How much? 1. Potassium supplementation should be administered gradually after symptom control When the patient has hypovolemia, peripheral circulatory failure, and renal dysfunction caused by shock, unless there is an emergency such as severe arrhythmia or respiratory paralysis, the blood volume should be supplemented, and urination should reach 30-40 mL/h After 6 hours of observation, potassium supplementation was given. Generally, potassium supplementation can be given when the urine output exceeds 500 mL/d.[3]. 2. Potassium supplementation rate
In general, the potassium chloride concentration should be controlled at 1.5-3.0 g/L, and the potassium supplementation rate should not exceed 1 g/h. For particularly severe hypokalemia (serum potassium < 2.5 mmol/L) and symptomatic, high-concentration potassium supplementation (potassium chloride concentration 3.0 g/100 mL) can be used, Potassium supplementation rate can reach 2 g/h[2, 3]. 3. Potassium Supplement Potassium deficiency When it is heavier, potassium chloride can be supplemented at 6-8 g/d. In severe potassium deficiency, the total amount of potassium chloride supplementation can reach 60-75 g or even more, and in the case of good renal function, the dosage can be as high as 18 g/d. And it usually takes a week or more for serum potassium to rise to the normal range[1, 3]. Summary1. Correct the cause of potassium loss and supplement potassium with both hands
For the treatment of hypokalemia, correction of the cause of potassium loss and the need for potassium supplementation Carry out the same period, otherwise, you will fall into the dilemma that the potassium supplement will be more and more, and the serum potassium will not rise to the normal value. 2. Intravenous and oral potassium supplementation makes a big differenceremove the cause of hypokalemia and exclude daily food After potassium intake (50-75 mmol/d):(1) Oral potassium supplementation: used to treat mild hypokalemia, 1 g potassium chloride tablet can increase serum potassium About 0.27 mmol/L;(2) Intravenous potassium supplementation: the situation is complicated and cannot be summarized by a simple formula. 3. Pay attention to the specific situation of intravenous potassium supplementationFor moderate, severe and particularly severe hypokalemia The rate and dosage of intravenous potassium supplementation vary widely in patients with ｜Extended readingPotassium supplement ≠ potassium chloride supplement, except potassium chloride, potassium citrate, Potassium acid and potassium magnesium aspartate can both be used for potassium supplementation. What is their potassium content? Which hypokalemia is used for each? Click“Read More” to get the answer! First Release | Clinical DrugsPlanning | Contribution | [email protected]