Because of this mechanism, shifting hydrogen and potassium between the ICF and ECF, acidosis can cause hyperkalemia, and hyperkalemia can cause acidosis. As with hypokalemia, it is nearly impossible for someone with normal renal function to spontaneously become hyperkalemic. Although it is much less common than hypokalemia, hyperkalemia is much more dangerous, and when unrecognized or untreated it may result in cardiac arrest.
It is therefore imperative that signs, symptoms and history suggestive of hyperkalemia are recognized, and immediate treatment is provided if indicated. Hyperkalemia is generally caused by decreased or impaired renal excretion, the addition of potassium to the extracellular space or transmembrane shifts of potassium. Simply increasing the dietary intake of potassium rarely causes hyperkalemia, as it is rapidly excreted by the kidneys. However, if the patient has a history of renal failure or is taking potassium-sparing diuretics or ACE inhibitors, an increase in dietary potassium can result in hyperkalemia.
For causes of hyperkalemia, see Figure 3. The signs and symptoms of hyperkalemia extend from the neuromuscular and cardiovascular systems. The most common finding is vague muscle weakness starting in the legs and ascending to the trunk and arms, and which can result in flaccid paralysis. The respiratory muscles may become involved, leading to hypoventilation, but this is often a late finding. Bradycardia in the hyperkalemic patient is often a preterminal event. Death is generally secondary to cardiac arrhythmias which may include various heart blocks, ventricular tachycardia, ventricular fibrillation and asystole.
For signs and symptoms of hyperkalemia, see Figure 4. It is imperative that the medical practitioner understand that the signs and symptoms of hyperkalemia relate poorly to actual potassium levels. As with most electrolyte emergencies, the best treatment may simply be to monitor the patient and notify the receiving facility of your suspicions.
Initial treatment of hyperkalemia includes the resolution of any compromise to the airway, breathing or circulation. Cardiovascular effects such as EKG changes, cardiac dysrhythmias or hypotension in the setting of suspected hyperkalemia deserve a heightened awareness of the possible need for intervention.
Indicators of imminent arrest, such as a widening QRS complex, warrant immediate treatment aimed at stabilization of the cardiac resting membrane potential RMP and movement of potassium into the ICF. Specific therapies to achieve this include:. Maintain an increased suspicion of hyperkalemia in patients presenting with weakness or in arrest if they have chronic renal failure or are on dialysis. Sign in. EMS World Expo. Current Issue. Issue Archives. Start Print Subscription.
Renew Print Subscription. Start Digital Subscription. Patient Care. Expo on Demand. CE Articles. Online Product Guide. Contact Us. Advisory Board. About Us. Copied to clipboard. Potassium Balance Disorders Potassium is the primary intracellular electrolyte, and because of its positive charge it is considered the primary intracellular cation. Calcium should be avoided in patients who take digitalis or if digitalis toxicity is suspected, as it can potentiate the effects of digitalis.
In this way, potassium will be absorbed into the cell, effectively lowering ECF potassium concentrations. Whether you have mild or severe hyperkalemia, you should get prompt medical attention to prevent possible complications. Several things can cause hyperkalemia, including health problems and use of certain medications. Kidney failure is the most common cause of high potassium. This can lead to potassium buildup. Heavy alcohol or drug use can cause your muscles to break down. This breakdown can release a high amount of potassium from your muscle cells into your bloodstream.
Certain kinds of trauma can raise your potassium levels as well. In these cases, extra potassium leaks from your body cells into your bloodstream. Burns or crush injuries where a large number of muscle cells are injured can cause these effects. The symptoms of high potassium depend on the level of the mineral in your blood. You may not have any symptoms at all.
But if your potassium levels are high enough to cause symptoms, you may have:. In extreme cases, high potassium can cause paralysis or heart failure.
If left untreated, high potassium levels can cause your heart to stop. If your symptoms are severe, call or go to the nearest emergency room.
A blood test or urine test can help your doctor diagnose hyperkalemia. Expect that EKG changes will return in 15 to 30 minutes if other measures are not taken to reduce serum potassium levels quickly. Do not administer with calcium gluconate as is not compatible. Flush IV well between infusions. Administer insulin 0. May repeat dose 30 to 60 minutes after first dose.
Monitor glucose hourly. May also consider infusion of insulin at 0. The most important adverse effect for the management of hypokalemia is overtreatment and iatrogenic hyperkalemia. To avoid this, one must carefully consider the urgency of treating hypokalemia, risk factors for an overresponse to intravenous replacement e.
Calcium chloride or Calcium gluconate: Can cause ventricular arrhythmia and cardiac arrest if given too fast. Calcium solutions must be given slowly over 3 to 5 minutes. Calcium chloride replacement is contraindicated in ventricular fibrillation. Both calcium solutions can cause significant tissue necrosis if extravasated. Do not use Calcium chloride peripherally.
Ensure the peripheral IV is working properly and is not infiltrated prior to administration. Sodium bicarbonate: Can cause hypernatremia, hypokalemia, hypocalcemia, and hypomagnesemia. Can also cause tissue necrosis with extravasation. In infants and neonates, use 4. Insulin and glucose: Can cause hypoglycemia or hyperglycemia. Blood sugars should be checked after each dose, or hourly if on infusion.
Sodium polystyrene: Can cause iatrogenic hypokalemia requiring potassium replacements if too much is given. Can also cause hypernatremia, hypocalcemia, and hypomagnesemia. There have been reports of colonic necrosis, gastrointestinal bleeding, colitis and perforation when used with sorbitol in patients with underlying gastrointestinal risk factors. Use with caution in patients with prematurity or evidence of gastrointestinal compromise.
Hemodialysis: Carries substantial risks from both the procedure of intermittent hemodialysis as well as the procedure of catheter placement necessary for performing dialysis. Should be used as last resort if above treatments fail. If left untreated, both severe hypokalemia and severe hyperkalemia can lead to paralysis, cardiac arrhythmias, and cardiac arrest.
Hyperkalemia, generally carries a higher risk of morbidity and mortality if left untreated. Severe hypokalemia may also cause respiratory failure, constipation and ileus. The most important aspect of prevention is consideration of comorbidities or medical therapies that may increase or decrease serum potassium levels, and then adjusting potassium intake as necessary.
To prevent hypokalemia, consider adding enteral potassium replacement to patients on a substantial amount of diuretics, patients with diarrhea or polyuria, or patients who may have heightened mineralocorticoid activity.
Also consider replacement of magnesium sulfate in conditions that can cause depletion of magnesium. To prevent hyperkalemia, consider restricting potassium replacement or eliminating potassium from intake in patients with renal disease, anuria, on ACE inhibitors, or with conditions with increased tissue breakdown such as rhabdomyolysis, burn injuries or crush injuries. Aune, GJ, Custer, Rau. A function of the kidney is to regulate blood levels of potassium to maintain homeostasis.
In the event of poor potassium intake, the kidney can lower potassium excretion to about 5 to 25 milliequivalents, thus maintaining a baseline serum potassium level of 3. Symptoms of hypokalemia manifest when serum potassium levels fall below 3. U waves are usually seen in the precordial leads of V4 to V6 refer to Figure 1. Other manifestations of hypokalemia include muscle weakness and rhabdomyolysis, as well as renal abnormalities: impaired concentrating ability, increased ammonia production, increased bicarbonate reabsorption, altered sodium reabsorption, hypokalemic nephropathy, and elevated blood pressure.
Hyperkalemia results when there is impaired excretion of potassium due to acute or chronic kidney disease, or disorders or drugs that inhibit the rennin-angiotensin-aldosterone axis. It causes cardiac conduction abnormalities , cardiac arrhythmias, muscle weakness, and paralysis.
0コメント