I. Applicable to.
1, patients who cannot eat or drink and rely only on parenteral nutrition.
2, patients with long-term application of potassium-depleting diuretics, which tend to cause hypokalemia.
3, certain diseases: patients with secondary aldosteronism, etc.
Second, the regular physiological potassium supplementation for normal people
It is about 3g of potassium per day (not 3g of potassium chloride), and adults need 3-4g of potassium per day (75-100mmol).
Potassium metabolism
Potassium is excreted mainly through urine, sweat and gastrointestinal fluids, and is affected by the pH of the blood.
1. Urinary potassium is mainly secreted through the collecting ducts and the distal tubules. Under normal circumstances, the intake and elimination of potassium in the body are in dynamic balance. (The principle of potassium supplementation is to see the urinary potassium supplementation); the kidneys have no effective potassium preservation ability, even if no potassium intake still need to excrete 30-50ml of potassium daily.
2. potassium excretion by skin sweating and stool.
3, potassium excretion from digestive juices, “hypochlorhydric hypokalemic alkalosis” in patients with pyloric obstruction who vomit a lot.
4. In metabolic acidosis, the inactivation of the sodium pump leads to high potassium in the extracellular fluid, so we use “polarized fluid” to deal with it.
Fourth, potassium supplementation and potassium chloride supplementation are not the same
Potassium chloride, potassium citrate, potassium acetate, potassium glutamate, potassium magnesium mentholate can be used for potassium supplementation in clinical practice, but potassium chloride is more commonly used. Potassium supplementation is not the same as no potassium chloride. The molecular weight of K is 39 and the molecular weight of KCl is 74.5, so 39 + 35.5 = 74.5. 100 mol of potassium and 100 mol of KCl contain the same 3.9 g of potassium. However, 1g of potassium and 1g of potassium chloride contain different potassium (1g of potassium chloride contains 0.53g of potassium), and clinically, potassium supplementation should be converted to international units for a potassium deficiency of 75mmol (3g)
1. If potassium chloride is used, it is 75×74.5=5589mg=5.6g (the simple memory of potassium supplementation is approximately the number of grams of potassium deficiency multiplied by 2).
2.If potassium acetate is used, it is about 7g.
3.If potassium citrate is used as a supplement, it is about 8g.
4.If potassium glutamate is used, it is about 17g.
V. Potassium deficiency and hypokalemia
3, 6, 9, potassium supplementation strategy, potassium supplementation principle as much as possible orally, see urine supplementation potassium.
1, mild potassium deficiency, serum potassium 3.0-3.5 mmol/l, need to replenish potassium 100 mmol (equivalent to 8g of potassium chloride).
2.Moderate potassium deficiency, serum potassium 2.5-3.0mmol/l, requiring 300mmol of potassium supplementation (equivalent to 24g of potassium chloride).
3.Severe potassium deficiency, with serum potassium 2.0-2.5 mmol/l, requires potassium supplementation of 500 mmol (equivalent to 40 g of potassium chloride).
Mild potassium deficiency is supplemented with an additional 3g of potassium chloride a day, moderate potassium deficiency is supplemented with an additional 6g of potassium chloride a day, and severe potassium deficiency is supplemented with an additional 9g of potassium chloride a day, if the patient cannot eat also remember to add the daily physiological amount of potassium supplementation that is plus 6g of potassium chloride.
Sixth, intravenous potassium concentration 0.3%, referring to the concentration of potassium chloride
1000ml of liquid plus potassium chloride should not exceed 3g, and generally do not go beyond this limit for the intravenous potassium concentration. The rate of intravenous potassium supplementation usually does not exceed 10-20mmol/h, if it exceeds 10mmol/h, cardiac monitoring is required, and 3g of potassium chloride is added every hour.
VII. Recommended intravenous potassium supplementation methods
1.10％ kcl：30ml Add 1000ml of liquid, the advantage is safe, the large vein can be, the disadvantage is that the amount of rehydration is larger.
2, 10% kcl: 15ml micro pump add to 35ml liquid, 8-20ml/h, the advantages of safe, small amount of rehydration, more potassium rehydration, vascular stimulation generally need central vein, cardiac monitoring when necessary.
3. 10% kcl: 30ml micro pump add to 20ml liquid, 10-50ml/h, potassium chloride 0.74g/h-3g/h (extreme amount), must cardiac monitoring, hourly blood gas measurement, hourly electrolyte measurement, equipped with resuscitation drugs.
Eight, persistent hypokalemia treatment
Appropriate supplementation of magnesium ion can quickly correct hypokalemia, but pay attention to avoid the inhibitory effect of magnesium ion on the heart, if there is cardiac inhibition timely application of calcium ion antagonism, which is also one of the reasons for the application of calcium chloride in hyperkalemia.
Nine, micro-pump potassium supplementation precautions
1. If PICC is available, it is best, followed by large vessels such as the elbow vein. The original indwelling needle for potassium supplementation cannot be applied.
2, if it is a large vessel generally the first minute will appear pain, generally do not advocate adding lidocaine in the liquid pain relief, you can use a small piece of gauze soaked with lidocaine to put on the blood vessels 1cm, pain relief effect is good, or external use with dermatoprene topical application of blood vessels, the feeling of mint will dilute the pain.
3, the speed as long as more than 3ml/h, generally will not block the tube, so there is no need to use saline to assist in flushing the tube, try to let it alone access.
4, micro-pump remaining a few ml will issue an alarm, is a high accident time period, with fast-forward function.
5, the patient can not unplug the micropump when going to the toilet, and then pick it up themselves, in the micropump potassium replenishment this is a very dangerous signal, must be eliminated.