The importance of serum potassium to the human body and the potential dangers of hypokalemia during surgery

Tuesday is Orthopedic Surgery Day. Yesterday night shift shift, today there is a patient, female, 56, high blood pressure, found high blood pressure only 3 months, taking high blood pressure drugs is unknown. In the third clavicle fixation removal operation in the morning, the doctor prescribed cervical plexus anesthesia.

Because the patient was admitted to the hospital yesterday morning, the liver function, biochemistry and electrolytes were not checked during the visit yesterday afternoon. The nurse said that the liver function, biochemistry, and electrolytes were urgently checked the next morning, and the operation was scheduled for the third operation at noon today.

Our hospital usually picks up patients by uncle nurses, and the first two surgeries went relatively smoothly. At 1:30 noon, the third patient was taken for internal fixation of the clavicle, and the patient was connected to the operation. After receiving various ECG monitoring, routinely check various test sheets, electrolytes, and serum potassium 2.7mmol/L. Surprised, he quickly asked the patient if he had any discomfort and contacted the surgeon by phone.

“Dr. Zhang, in your XX bed, have you checked the serum potassium of the patient with internal fixation of the clavicle? The potassium on the test sheet is only 2.7mmol/L. Please take a look and contact the laboratory. See if there is a problem with the test sheet. If you want to review the electrolytes, take the patient back to check the blood potassium first, and temporarily stop the operation.”

Dr. Zhang may have heard that the operation was stopped, and he felt a little unhappy. He said something that made my jaw drop immediately. Low blood potassium shuts you down for anesthesia. If you hit you, Anesthesia, it’s none of your anesthesia. This sentence immediately stunned me. I don’t even know how to start it. The hospital stipulates that the critical value of blood potassium is 2.8mmol/L. If it is lower than 2.8mmol/L, it should be reported to the hospital immediately. The patient’s blood potassium was 2.7mmol/L, and he asked Ma Guan anesthesiologist what was going on, and he petrified me immediately.

I don’t know if he really didn’t understand it or if it was intentional, so I had to be patient and tell him about the dangers of low potassium. What are the dangers of low potassium? Potassium has a great influence on the muscular system, cardiovascular system, urinary system and digestive system. Hypokalemia is mainly due to two aspects: insufficient intake of potassium and excessive excretion of potassium, resulting in potassium deficiency, which can cause hypokalemia or hypokalemia.

1. Neuromuscular system

Potassium deficiency can cause damage to the neuromuscular system. Will reduce the excitability of muscle cells, muscle weakness, muscle paralysis and other symptoms. The central nervous system is mostly normal and conscious, but there may be mental symptoms such as apathy, depression, drowsiness, memory and orientation loss or loss.

2. Cardiovascular system

Potassium deficiency can reduce myocardial irritability and cause various arrhythmias and conduction block. In mild cases, sinus tachycardia, atrial or premature ventricular contractions, Ventricular block; severe cases of paroxysmal atrial or ventricular tachycardia, or even ventricular fibrillation. Potassium deficiency can aggravate digitalis and antimony poisoning, which can lead to death.

3. Urinary system

Long-term potassium deficiency can damage renal tubules and cause potassium-deficient nephropathy. The functions of renal tubule concentration, ammonia synthesis, hydrogen secretion and chloride ion reabsorption can be reduced or enhanced, and sodium excretion can be enhanced. The function or ability to reabsorb sodium can also be impaired, resulting in metabolic hypokalemia, hypochloremic alkalosis.

4. Digestive system

Potassium deficiency can slow down intestinal peristalsis. Mild potassium deficiency only has anorexia, abdominal distension, nausea and constipation; severe potassium deficiency can cause paralytic ileus.

If a patient has hypokalemia, the cause can be investigated and then treated. Generally, patients with serum potassium of 3.5 to 4 mmol/L do not need additional potassium supplementation. Patients should eat more potassium-rich foods, such as fresh vegetables, fruit juice and meat. Those whose serum potassium is lower than 3.0mmol/L should supplement potassium. In mild cases, only oral potassium is needed, and 10% potassium chloride is the first choice. Severely ill patients should be intravenously infused with potassium preparations, and the commonly used preparations are also potassium chloride, which should be monitored during the infusion process.

Besides, if this patient has respiratory muscle paralysis and weakness during cervical plexus anesthesia, how should I judge and how to deal with it? Are these symptoms the result of a blocked diaphragm or low potassium levels? If the patient is nauseous and vomiting, what should I do? If the patient suffers from respiratory muscle paralysis caused by hypokalemia, respiratory muscle weakness, and then coupled with the cervical plexus, after the diaphragm is blocked, the patient will experience severe hypoventilation, hypoxia and carbon dioxide accumulation, which will cause the patient to die.

Dr. Zhang, only then did I realize the seriousness of the matter, so I quickly reviewed the electrolytes, suspended the operation, and found out the cause first…

It was later found out that the hypokalemia was caused by taking indapamide sustained-release tablets. After several days of potassium supplementation, the patient’s blood potassium quickly returned to normal. After a few days, the internal fixation was removed, and he recovered and was discharged from the hospital soon.

Author: Zhejiang Xin’an International Hospital, Tang Huadong (Jiaxin Tang)

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