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How is hyperkalemia treated?
Abnormal serum potassium is very common in clinical practice. Because potassium ions are involved in the electrophysiological activities of cells, hyperkalemia or hypokalemia may lead to arrhythmia and severe They may even experience cardiac arrest and sudden death. Potassium supplementation in hypokalemia and potassium reduction in hyperkalemia are both basic clinical skills.
The application of intravenous calcium is very important in the rescue of hyperkalemia. Commonly used intravenous calcium in clinical practice includes calcium chloride and calcium gluconate.
Which calcium supplement is better or worse? When hyperkalemia occurs, how should two calcium agents be selected? Today we come together.
Hyperkalemia Treatment and Calcium
To clarify these issues, let’s review some basics.
Potassium ion is one of the most important ions to maintain the normal life activities of the human body. Under normal physiological conditions, the serum potassium ion concentration is between 3.5-5.5mmol/L, and the serum potassium ion concentration is greater than 5.5mmol/L. /L is hyperkalemia, 6-7mmol/L is moderate hyperkalemia, and greater than 7mmol/L is severe hyperkalemia.
Hyperkalemia primarily affects the heart and skeletal muscles. Cardiac manifestations of arrhythmia and conduction block, ECG changes including T wave peak, ST segment elevation, PR interval prolongation, widened QRS complex, atrioventricular block, ventricular block, ventricular fibrillation and even asystole. It may present as palpitations, syncope, or asystole.
The effect of hyperkalemia on skeletal muscle is rare, and it can be manifested as muscle weakness, spontaneous muscle contraction of limbs, and sustained elevation of serum potassium can eventually manifest as flaccid paralysis of the limbs, but the trunk, Head and respiratory muscles are not easily affected, and respiratory failure is rare. Therefore, when hyperkalemia occurs, the identification and monitoring of cardiac damage-related manifestations is the focus of treatment.
Both are important elements to maintain human life activities, calcium ions and potassium ions have an antagonistic effect on each other. In hyperkalemia, the application of calcium ions can stabilize the cell membrane potential, make the threshold potential of cardiomyocytes move up, increase the gap between the resting potential and the threshold potential, and prevent ventricular arrhythmias. Therefore, intravenous calcium injection plays an important role in the rescue of hyperkalemia.
Fig. 1 Potassium and calcium currents play an important role in maintaining the action potential of cardiomyocytes
For the treatment of hyperkalemia, especially severe hyperkalemia, the clinical priorities of different treatment options are emphasized as follows:
Priority treatment: Stabilizes cell membranes in minutes. The most common treatment options are intravenous calcium and alkalization.
Second priority treatment: The next 30-90 minutes to allow potassium to move into the cell, such as the usual insulin plus glucose solution; nebulized beta2 adrenergic agonist, such as terbutaline etc. are also valid. β2-receptor agonists are suitable for hyperkalemia ineffective with conventional therapy, but should be used with caution in patients with cardiovascular disease.
Follow-up treatment: Begin longer-term monitoring of potassium levels and excretion of potassium ions from the body. Common treatment options include the use of diuretics (loop diuretics and thiazide diuretics), cation exchange resins, and dialysis.
Chronic treatment: including finding and correcting possible causes of hyperkalemia, dietary control, correction of metabolic acidosis, alkalization of urine, correction of hypoaldosteronemia, etc.
Hyperkalemia, how should calcium be used?
Calcium gluconate and calcium chloride are two types of intravenous calcium commonly used clinically, both of which can be used to treat hyperkalemia.
Intravenous injection has a fast onset of action, lasting 30-60 minutes. Calcium injection should be slow, 1-2ml/min. Otherwise, it may cause adverse reactions such as fever, nausea, dizziness, and fainting in the whole body or throat. In severe cases, it may cause arrhythmia, ventricular fibrillation, and even cardiac arrest.
The specific uses of the two calcium agents are as follows:
Table 1 Treatment options for hyperkalemia with intravenous calcium
Although both calcium agents can be used in the rescue of hyperkalemia, there are certain differences, including:
Difference in calcium content: the molecular weight of calcium chloride is 111, and one molecule of calcium chloride contains one calcium ion; while the molecular weight of calcium gluconate is 430.37, and one molecule of glucose Calcium acid also contains a calcium ion. Therefore, two solutions of equal concentration and equal volume, the calcium content of calcium chloride is more than three times that of calcium gluconate, and the risk of hypercalcemia is higher when used.
Differences in skin irritation: Calcium chloride is highly irritating and should not be administered subcutaneously or intramuscularly; if it leaks out of blood vessels during intravenous injection, it may cause Tissue necrosis, so conditional patients are better to choose central intravenous administration, which limits the use of calcium chloride to a certain extent. Compared with calcium chloride, calcium gluconate is more “softer” in skin irritation and is safer to be administered peripherally.
Apply calcium, and pay attention to these hyperkalemia complications!
Although calcium plays an important role in the rescue of hyperkalemia, it is not applicable to all situations. Before using calcium, you should know the contraindications and precautions of its application. to avoid serious arrhythmia.
Digitalis is a class of commonly used drugs in clinical practice, mainly used to improve the symptoms of patients with heart failure and control the ventricular rate of patients with atrial fibrillation. The therapeutic concentration of digitalis drugs is close to the toxic concentration, and calcium and digitalis drugs have synergistic effects. Hypercalcemia can increase the Ca2+ overload and spontaneous Ca2+ release in cardiomyocytes, thereby increasing the arrhythmia induced by digitalis drugs. risk. Therefore, in patients with hyperkalemia, when digitalis drugs are used at the same time or the withdrawal time is short, calcium injection is contraindicated.
The use of calcium supplements at the same time as thiazide diuretics or estrogens can increase the reabsorption of calcium by the kidneys, which can easily lead to hypercalcemia. In addition, in patients with excessive vitamin D, calcium absorption increases when calcium is used, which is also prone to lead to hypercalcemia. Therefore, in addition to monitoring the serum potassium level, the serum calcium level should be closely monitored in patients with hyperkalemia after application of calcium agents, so as to avoid excessive increase of calcium ion concentration, hypercalcemia, and induction of arrhythmia.
References:
[1] Fan Weiguo. Electrocardiographic pattern, mechanism and prospect of electrolyte disturbance. Chinese Journal of Circulation, 2021, 36(1): 88-92.
[2] Zhao Guangyuan, Wang Quan. Hyperkalemia and hypokalemia crisis. China Pediatric Emergency Medicine, 2020, 27(8): 572-576.
[3] Su Yongsheng, Han Mei, Meng Qingyi. First aid measures for hyperkalemia from the perspective of time. Chinese General Medicine, 2012, 15(17): 1995-1997.< /p>
[4] Tao Juhua, Li Zeqin. Problems that should be paid attention to and how to deal with calcium injection. China Rural Medicine, 2002, 9(8): 33-34.
[5] Instructions for Calcium Chloride Injection.
[6] Instructions for calcium gluconate injection.
Source of this article: Clinical Pharmacy Channel of the Medical Community
This article was written by Myelin
Editor in charge: Yuan Xueqing, Zhang Li
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