Potassium serves as the major intracellular cation and helps balance sodium levels in the extracellular fluid to maintain the electroneutrality in the body. Moreover, it is excreted by the kidneys, around 40 mEq of potassium in 1 liter (L) of urine. The body doesnt produce potassium. Therefore, it needs to be replenished daily through dietary sources. The body also uses potassium to exchange for a hydrogen ion when changes in the body's pH require a cation to exchange. This occurs in metabolic alkalosis or other alterations that lead to increased cellular uptake of potassium, including kidney failure and excessive insulin administration. Hypokalemia mainly occurs when there is an increase in the potassium concentration gradient between the intracellular and extracellular fluid.
Two factors that affect serum potassium levels are aldosterone and hyperkalemia. The body secretes aldosterone in response to high renin and angiotensin II or hyperkalemia. When the plasma potassium level is high, the renal potassium loss also increases. Since 98% of the bodys potassium is intracellular, little changes in the potassium gradient can cause major changes in the membrane excitability.
Hypokalemia is a relatively common electrolyte imbalance with life-threatening consequences because it can affect almost all body systems. Common complications of hypokalemia include cardiac dysrhythmias, paralytic ileus, shock, and sudden death. Therefore, it has to be managed promptly. If a patient is at risk of hypokalemia, closely monitor their serum potassium levels.
What Causes Hypokalemia?
Hypokalemia occurs because of decreased potassium intake, transcellular shifts, and renal and non-renal potassium loss.
Conditions that can lead to decreased potassium intake are fad diets, anorexia, no oral food intake for a long time, and long-term dependence on IV fluids without potassium.
Moreover, abnormal movement of potassium from the extracellular fluid to the intracellular fluid can occur because of alkalosis, hyperinsulinism, hyperalimentation, and transfusion of frozen red blood cells, which are low in potassium.
Renal excretion of potassium can occur due to prolonged use of potassium-wasting diuretics, such as acetazolamide, ethacrynic acid, furosemide, bumetanide, and thiazide, the diuresis phase after severe bodily burns, increased secretion of aldosterone as in Cushings syndrome, and renal disease that has impaired reabsorption of potassium.
The non-renal causes of potassium wasting include prolonged use of digitalis or corticosteroids, laxative abuse, excessive vomiting or diarrhea, excessive diaphoresis, excessive wound drainageespecially gastrointestinaland prolonged nasogastric suctioning. If your patient has a history of these conditions, check their serum potassium levels promptly to see if they have hypokalemia, which needs to be corrected.
History
If you suspect the patient has hypokalemia, inquire about their dietary intake, recent illness, recent medical or surgical interventions, and medication use, especially corticosteroids and diuretics. Inquire about over-the-counter and prescribed medications and for how long they have been taking them. Often, patients with hypokalemia complain about nausea, anorexia, drowsiness, fatigue, lethargy, leg cramps, and muscle weakness. Check the patients mental status and usual mood because hypokalemia causes changes in behavior and cognitive abilities and altered levels of consciousness.
Physical Examination
A problematic thing about hypokalemia is that it doesn't cause many symptoms until the serum potassium level falls below 3 mEq/L, leading to life-threatening consequences silently. Common symptoms of hypokalemia include anorexia, lethargy, nausea, vomiting, muscle weakness, and leg cramps. Assess the patients level of consciousness and orientation. Patients with hypokalemia are often anxious, confused, apathetic, irritable, and, in severe cases, even comatose.
Check the patients respiratory rate and depth of respiration, the color of nail beds, and mucous membranes. Note any cardiovascular changes, such as weak and thready peripheral pulses and heart rate variability. The apical pulse may be excessively slow or fast, depending on the type of dysrhythmia present. Monitor the patients blood pressure closely when lying, sitting, and standing, checking for postural hypotension. These symptoms often occur in the earlier stages and deteriorate to a generalized hypotensive state in the advanced stages of hypokalemia. Check the presence of skeletal muscle weakness with the help of bilateral weak hand grasps, hyporeflexia, inability to stand, and profound flaccid paralysis. Moreover, gastrointestinal function is also altered with hypokalemia, and the patient may have abdominal distention and hypoactive bowel sounds.
Hypokalemia is seldom long-standing and can be easily corrected, but even for a short time, it can lead to life-threatening consequences. Along with the hypokalemic state, the patient also deals with the underlying cause of the hypokalemia. Therefore, assessing the patients ability to cope with these conditions is essential.
Pharmacological Highlights
Depending on how low the potassium level is, the patient may be given potassium through the IV route to correct hypokalemia. Administer IV potassium solutions through a pump device or controller to regulate the rate of administration. Mix oral potassium supplements in at least 4 ounces of fluid or food to prevent gastric irritation. Angiotensin-converting enzyme inhibitors may be used to reduce some symptoms of hypokalemia. However, administer that with caution in patients with renal dysfunction.
Potassium chloride is given through oral or IV routes. The oral dose is 10 to 40 mEq orally, depending on the severity of the potassium deficit. IV dosage should not exceed 20 mEq per hour except in unusual situations when 40 mEq per hour is given for critical cases.
To correct hypokalemia, potassium replenishment is necessary. Dilute IV potassium solutions before administration because rapid IV administration can be dangerous as a rapid increase in serum potassium levels depresses the cardiac muscle contractility and can lead to life-threatening dysrhythmias.
Nursing Planning and Implementations
To prevent hypokalemia, closely monitor serum potassium levels, especially if the patient takes medications like corticosteroids and diuretics. If potassium levels are slightly lower than normal, oral potassium supplements may be prescribed. Most patients who develop hypokalemia are placed on either parenteral or oral potassium supplementation. Keep in mind that potassium is not usually administered through intramuscular and subcutaneous routes because it's a profound tissue irritant. Moreover, potassium should also be administered with extreme caution as it can cause vein irritation and chemical phlebitis when given through the IV route.
Encourage the patient to eat a potassium-rich diet to replenish the lost potassium and prevent further loss. Educate them that consuming a healthy and balanced diet is essential for the body's functioning. Collaborate with a registered dietician to create a customized diet plan for your patient according to their requirements. Common foods containing high potassium are skim milk, mushrooms, avocados, raisins, cantaloupe, bananas, dates, potatoes, tomatoes, and spinach. Encourage your patient to consume them in ample amounts to prevent potassium loss in the future, especially if they take medications that deplete potassium stores.
Nursing interventions with hypokalemia focus on preventing potassium imbalance in the future, restoring normal potassium balance, and providing supportive care for altered body functions until hypokalemia is resolved. Teach all patients who take potassium-depleting medications to increase potassium intake through dietary sources. Encourage them to consume bulk-forming foods and drink at least 2 L of fluid in a day unless there is a fluid restriction by the healthcare provider because of health conditions. Evaluate if the patient has enough knowledge about dietary potassium sources and teach them and their caregivers the necessary information. For patients with hypokalemia, it is imperative to take safety measures to prevent falls because of weakness, fatigue, or confusion. Raise the side rails when the patient is in bed and assist them in getting out of bed.
Teach all patients, especially those on diuretics, to practice measures to increase potassium intake in their diet. Also, educate them about the signs and symptoms of hypokalemia, such as slight confusion, muscle weakness, leg cramps, slow or irregular heart rate, forgetfulness, abdominal distention, inability to concentrate, and nausea. If they have any of these symptoms, they should report them to their healthcare provider promptly, without any delay. Teach the patient and their caregivers how to take a pulse, monitor it daily in the morning, and keep a daily record of the pulse rate. Tell the patient and their caregivers to give oral potassium supplements with at least 4 ounces of fluid or with food and not to give it on an empty stomach. Instruct the patient to report any complaints of irritability, extreme anxiousness, confusion, extreme muscle fatigue, dizziness, heart palpitations, and difficulty breathing to the primary healthcare provider.
The Bottom Line
Hypokalemia is a serious life-threatening condition in which the serum potassium levels go below 3.5 mEq/L. Most commonly, it happens in patients receiving medications such as corticosteroids or diuretics. Combining a potassium-sparing diuretic can help prevent hypokalemia in some cases. Educate the patient at risk to report to their healthcare provider soon if they have any symptoms of hypokalemia, as it can lead to life-threatening dysrhythmia and shock.
About the Author:
Mariya Rizwan is an experienced pharmacist who has been working as a medical writer for four years. Her passion lies in crafting articles on topics ranging from Pharmacology, General Medicine, Pathology to Pharmacognosy.
Mariya is an independent contributor to CEUfast's Nursing Blog Program. Please note that the views, thoughts, and opinions expressed in this blog post are solely of the independent contributor and do not necessarily represent those of CEUfast. This blog post is not medical advice. Always consult with your personal healthcare provider for any health-related questions or concerns.
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