Presentation The classic presentation of hyperkalemia is typically underwhelming. No signs or symptoms are pathognomonic for this condition, although patients may rarely present with weakness or paresthesias. [saem.org]

An extensive literature review has been performed to present a comprehensive review of the causes and treatment of hyperkalemia. [ncbi.nlm.nih.gov]

• Fatigue

  Central muscle fatigue manifests as an overall sense of energy deprivation, while peripheral muscle fatigue manifests as a local, muscle-specific inability to do work.[1][2] Neuromuscular fatigue[edit] Nerves control the contraction of muscles by determining [en.wikipedia.org]

  It can cause: Muscle fatigue Weakness Paralysis Abnormal heart rhythms (arrhythmias) Nausea Nov. 18, 2011 References Laboratory reference values. Potassium values. Rochester, Minn.: Mayo Foundation for Medical Education and Research. July 2011. [web.archive.org]

  It can cause: Muscle fatigue Weakness Paralysis Abnormal heart rhythms (arrhythmias) Nausea Jan. 11, 2018 References What is hyperkalemia? National Kidney Foundation. https://www.kidney.org/atoz/content/what-hyperkalemia. Accessed Oct. 4, 2017. [mayoclinic.org]

  Pearls and Pitfalls Obtain an ECG on patients with chronic kidney disease who present with generalized fatigue and weakness to quickly screen for hyperkalemia. [saem.org]

  However, some individuals with hyperkalemia have reported nausea, fatigue, weakness, tingling, slow heart beat or faint pulse. How is Hyperkalemia Treated? There are several different approaches to treat hyperkalemia. [healthcentral.com]

• Hypothermia

  Hyperthermia and hypothermia may lead to rhabdomyolysis. Rhabdomyolysis is a syndrome characterized by muscle necrosis and the release of intracellular muscle constituents into the circulation. [ncbi.nlm.nih.gov]

  Part 12.9: Cardiac Arrest in Accidental Hypothermia Unintentional or accidental hypothermia is a serious and preventable health problem. [doi.org]

  […] causes: Increased entry into cells due to: Increases in the activity of the Na-K-ATPase pump Increased availability of insulin Elevated beta-adrenergic activity Elevation in extracellular pH Hypokalemic periodic paralysis Increased blood cell production Hypothermia [acls.com]

  Cardiac arrest in special circumstances: Electrolyte abnormalities, poisoning, drowning, accidental hypothermia, hyperthermia, asthma, anaphylaxis, cardiac surgery, trauma, pregnancy, electrocution.”. [ko.wikipedia.org]

• Acutely Ill Patient

  The patient is admitted to the hospital and stabilized, and is ultimately discharged home with improved renal function. References Depret, F., et al., Management of hyperkalemia in the acutely ill patient. Ann Intensive Care, 2019. 9(1): p. 32. [saem.org]

  Management of hyperkalemia in the acutely ill patient. Annals of Intensive Care. 2019; 9 (1). doi: 10.1186/s13613-019-0509-8. | Open in Read by QxMD Jameson JL, Fauci AS, Kasper DL, Hauser SL, Longo DL, Loscalzo J. [amboss.com]

  Management of hyperkalemia in the acutely ill patient. Ann Intensive Care. 2019 Feb 28;9(1):32. doi: 10.1186/s13613-019-0509-8 [PubMed] 31084947 Moussavi K, Fitter S, Gabrielson SW, Koyfman A, Long B. [emcrit.org]

• Fever

  […] strains.[4] Autoimmune[edit] Multiple sclerosis (neurologic pain interpreted as muscular) Myalgic Encephalomyelitis (chronic fatigue syndrome) Myositis Mixed connective tissue disease Lupus erythematosus Fibromyalgia syndrome Familial Mediterranean fever [en.wikipedia.org]

  […] aspartate transaminase, aldolase), and myoglobin.19 In rhabdomyolysis, myoglobin accumulation and hypovolemia lead to AKI and hyperkalemia.19 Patients may present with myalgias, extremity paresthesias, generalized weakness, nausea, altered mental status, fever [mdedge.com]

  She had no documented fever, no history of trauma, no gastroenterological symptoms and no other recent complaints before this event. On arrival to the emergency department, she was confused with a lethargic mental status and dry mucous membranes. [omicsonline.org]

  Ask about associated pain, discharge, bladder symptoms, nausea and vomiting, fever, infertility, and other history points. [ncbi.nlm.nih.gov]

• Respiratory Insufficiency

  In our case a 44 year-old man with septic shock was mechanically ventilated for 13 days, extubated but because of respiratory insufficiency reintubated. During induction an increase in p-potassium (4.2-11.7 mmol/l) caused ventricular fibrillation. [research.regionh.dk]

  CASE REPORT: We presented a male patient, aged 50, hospitalized in the Emergency Center Kragujevac due to altered mental status (Glasgow Coma Score 11), partial respiratory insufficiency (pO2 7.5 kPa, pCO2 4.3 kPa, SpO2 89%), weakness of lower extremities [ncbi.nlm.nih.gov]

  If infused rapidly, it can be metabolized to carbon dioxide, or in those with respiratory insufficiency, can result in acidosis or hyperkalemia. [uspharmacist.com]

• Nausea

  […] excrete potassium in exchange for sodium.2 Metabolic acidosis, which often contributes to AKI or CKD, causes potassium to shift from the intracellular to the extracellular compartment.4 Renal impairment may present clinically with dehydration, oliguria, nausea [mdedge.com]

  The patient presented with continuous tachycardia, palpitations, chest tightness, progressive nausea, irritability, progressive myasthenia gravis. Hyperkalemia, sepsis, acidosis, diabetes, postoperative esophageal cancer. [ncbi.nlm.nih.gov]

  It can cause: Muscle fatigue Weakness Paralysis Abnormal heart rhythms (arrhythmias) Nausea Nov. 18, 2011 References Laboratory reference values. Potassium values. Rochester, Minn.: Mayo Foundation for Medical Education and Research. July 2011. [web.archive.org]

  It can cause: Muscle fatigue Weakness Paralysis Abnormal heart rhythms (arrhythmias) Nausea Jan. 11, 2018 References What is hyperkalemia? National Kidney Foundation. https://www.kidney.org/atoz/content/what-hyperkalemia. Accessed Oct. 4, 2017. [mayoclinic.org]

• Abdominal Pain

  This study aimed to report on a toddler who presented with progressively worsening abdominal pain and obstructive uropathy 1 week after ureteral valve reimplantation. Acute renal failure resulted in critical hyperkalemia. [ncbi.nlm.nih.gov]

  pain showed a high serum potassium level of 6.6 mmol/L (reference range 3.5-5.3 mmol/L). 1 She was otherwise well and not taking any medications. [doi.org]

  Muscle cramps or pain Diarrhea Abdominal pain Numbness or weakness How is hyperkalemia diagnosed? An EKG test records your heart rhythm and how fast your heart beats. It is used to check for irregular heartbeats. [drugs.com]

  Colitis due to SPS occurs in 1% of the cases, especially in postsurgical patients and patients with advanced renal disease, the last condition as was the case of our patient. 3,4 Clinical presentation varies, ranging from abdominal pain, nausea, diarrhea [scielo.mec.pt]

  A similar observation was recently reported about carvedilol-induced hyperkalemia in a 69-year-old man with hypertension, type II diabetes, and stage III renal insufficiency who was hospitalized for abdominal pain [2]. [hindawi.com]

• Hypotension

  An 85 year-old woman on a drug regimen of sotalol, valsartan, spironolactone, and trimethoprim-sulfamethoxazole presented to the emergency department with hypotension and bradycardia. [ncbi.nlm.nih.gov]

  […] toxicity Clinical Features of Hyperkalemia History and examination findings Neurological effects Paraesthesia Weakness and flaccid paralysis (diaphragm is usually spared) Loss of reflexes Normal cranial nerves Normal sensory function Cardiovascular effects Hypotension [derangedphysiology.com]

  The clinician should have a high index of suspicion for hyperkalemia in patients with chronic renal failure and other predisposing conditions, particularly in the setting of hypotension or shock. [saem.org]

  Amal Mattu’s ECG Case of the Week – January 21, 2019 HPI: A 50-year-old male is brought into the emergency department from prison with bradycardia, hypotension, and altered mental status. [ecgweekly.com]

  It can also cause urinary sodium wasting, leading to volume depletion and hypotension. [en.wikipedia.org]

• Heart Block

  J Emerg Med 1986; 4: 449-55. 2005 American Heart Association Guidelines for Cardiopulmonary Resuscitation and Emergency Cardiovascular Care. Circulation 2005; 112: 121-5. Przybojewski JZ, Knott-Craig CJ. Hyperkalaemic complete heart block. [medigraphic.com]

  With severe hyperkalemia, the most significant effect is on the cardiovascular system with dysrhythmias including 2nd or 3rd degree heart block, wide complex tachycardias, and progression to ventricular fibrillation and asystole. [saem.org]

  With severe hyperkalemia, the most significant effect is on the cardiovascular system with dysrhythmias including 2 nd or 3 rd degree heart block, wide complex tachycardias, and progression to ventricular fibrillation and asystole. [cdemcurriculum.com]

• Flushing

  The FFK was 18.8 mmol/L after flushing with 1000 mL of 5% albumin. [ncbi.nlm.nih.gov]

  It has been shown to work, but only in patients with hyponatremia and concurrent hyperkalemia 50 ml of 3% saline pushed Shift the potassium intracellularly Insulin regular 10 units IV Make sure to flush after injecting the insulin, because it is a tiny [first10em.com]

  Tumor lysis syndrome Hemolysis High blood cell turnover: e.g., thrombocytosis, erythrocytosis, leukocytosis Pseudohyperkalemia: resulting from iatrogenic red blood cell lysis Blood drawn from the side of IV infusion or a central line without previous flushing [amboss.com]

• Muscle Weakness

  Careful monitoring of electrocardiogram changes and muscle weakness in hyperkalemia is important to determine its functional consequences. If these are observed to be severe, immediate correction of hyperkalemia is essential. [acls.com]

  Ascending muscle weakness is a manifestation of hyperkalemia that can progress to flaccid paralysis that is comparable to Guillain-Barre syndrome.10 Hyperkalemic periodic paralysis is an autosomal dominant mutation of sodium channels in skeletal muscles [resources.acls.com]

  Patients are usually asymptomatic, but can develop: nausea palpitations muscle weakness, often starting in legs muscle cramping paresthesias and numbness Physical Exam Signs of hyperkalemia include: weakness areflexia ascending paralysis hypoventilation [sharinginhealth.ca]

  Hyperkalemia causes muscle weakness (paresthesias followed by weakness and finally flaccid paralysis) and cardiac toxicity. At serum K of 6mEq/L tall T waves appear on EKG, at serum of 7mEq/L the PR interval is prolonged. [cancertherapyadvisor.com]

  Muscle Weakness, Urine, Respiratory Distress, Decreased Cardiac Contractility, EKG Changes and Reflexes. Next thing I wanna talk about with hyperkalemia is the management AIRED, AIRED. [nrsng.com]

• Flaccid Paralysis

  In severe cases, weakness and flaccid paralysis may occur. [icd9data.com]

  Fluoride toxicity Clinical Features of Hyperkalemia History and examination findings Neurological effects Paraesthesia Weakness and flaccid paralysis (diaphragm is usually spared) Loss of reflexes Normal cranial nerves Normal sensory function Cardiovascular [derangedphysiology.com]

  In 94 patients, flaccid paralysis was described and in 25, severe muscular weakness; in 65 patients, these findings were associated with other symptoms. Concurrent renal failure was often documented. [ncbi.nlm.nih.gov]

• Paresthesia

  Neuromuscular depolarization can also lead to poor action potentials, with accompanying paresthesias and weakness. return to top Signs, Symptoms, and Diagnosis history physical exam ECG changes lab investigations History A careful history, with emphasis [sharinginhealth.ca]

  No signs or symptoms are pathognomonic for this condition, although patients may rarely present with weakness or paresthesias. [saem.org]

  Signs and symptoms Patients with hyperkalemia may be asymptomatic, or they may report the following symptoms (cardiac and neurologic symptoms predominate): Generalized fatigue Weakness Paresthesias Paralysis Palpitations Evaluation of vital signs is essential [emedicine.com]

• Absent Deep Tendon Reflexes

  deep tendon reflexes Diagnosis Suspect hyperkalemia in ALL patients with renal impairment, especially end-stage renal disease (ESRD) Serum potassium Can be artificially elevated by extravascular hemolysis Blood gas results may differ from standard metabolic [coreem.net]

  deep tendon reflexes When hyperkalemia is discovered, investigate potential pathophysiologic mechanisms. [emedicine.medscape.com]

• Asthenia

  The term myasthenia is from my- from Greek μυο meaning "muscle" + -asthenia ἀσθένεια meaning "weakness". Types[edit] Neuromuscular fatigue can be classified as either "central" or "peripheral" depending on its cause. [en.wikipedia.org]

• Hyperreflexia

  And R – Reflexes, hyperreflexia or areflexia, they’re flaccid. So, MURDER, MURDER. Muscle Weakness, Urine, Respiratory Distress, Decreased Cardiac Contractility, EKG Changes and Reflexes. [nrsng.com]

See Workup for more detail. [emedicine.com]

• Left Axis Deviation

  Left axis deviation. Absent P waves. Example 6 Hyperkalaemia: Sine wave appearance with severe hyperkalaemia (K+ 9.9 mEq/L). Example 7 Hyperkalaemia: Huge peaked T waves. Sine wave appearance. [lifeinthefastlane.com]

• Thrombocytosis

  Contributing factors include repeated fist clenching, hemolysis, and marked leukocytosis or thrombocytosis. True hyperkalemia occurs as a result of one of the following: Transcellular shift. [unboundmedicine.com]

  Examples of artifactual causes include hemolysis, delays in centrifugation, contamination, and pseudohyperkalemia caused by thrombocytosis/leucocytosis. [aacc.org]

  Spurious/Pseudohyperkalemia  Leakage from erythrocytes when separation of serum from clot is delayed (plasma K+ normal)  Marked thrombocytosis or leukocytosis with release of intracellular K+ (plasma K+ normal)  Repeated fist clenching during phlebotomy [accessmedicine.mhmedical.com]

  Obstructive uropathy, lupus nephritis, sickle cell disease Acute Kidney injury - Low GFR and oliguria causes decrease potassium filterin causing hyperkalemia SPURIOUS CAUSES OF HYPERKALEMIA Hemolysis, thrombocytosis, leukocytosis, tourniquet CLINICAL [youtube.com]

  Pseudohyperkalemia is caused by hemolyzed sample, poor phlebotomy technique leukocytosis or thrombocytosis. [emergencymedicinecases.com]

• Potassium Increased

  OBJECTIVE: To compare different strategies predicting hyperkalemia (serum potassium level ≥5.5 mEq/l) in hospitalized patients for whom medications triggering potassium-increasing drug-drug interactions (DDIs) were ordered. [ncbi.nlm.nih.gov]

  In general, sudden serum potassium increases can lead to significant ECG abnormalities, while those that occur progressively over time can produce fewer ECG manifestations. [emdocs.net]

  In general, there are 3 mechanisms by which hyperkalemia occurs: increased potassium release from cells, increased potassium intake, and decreased potassium excretion. [visualdx.com]

  Increased urinary loses – potassium excretion occurs mostly in the distal nephrons and increased losses may be seen in diuretic use, increased aldosterone secretion, nonreabsorbable anions, and loss of gastric secretions. [acls.com]

• Potassium Decreased

  All patients took small doses of CPS (8.0 ± 3.6 g/d), and serum potassium decreased in a dose-dependent fashion. Serum potassium of all patients decreased significantly from 5.8 ± 0.3 mmol/L to 4.9 ± 0.7 mmol/L with CPS treatment (P < 0.001). [ncbi.nlm.nih.gov]

  Lower potassium dialysate and increased blood flow can result in faster serum potassium decreases. 4,5 – Increases in machine blood pump speed and plasma-to-dialysate concentration can decrease potassium within minutes; thus the importance of dialysis [emdocs.net]

  […] agonists decrease potassium levels Cyclosporine (Sandimmune) Suppresses renin release, leading to decreased aldosterone synthesis, decreased potassium secretion in collecting duct Digoxin at toxic levels Decreases sodium-potassium ATPase activity Fluoride [aafp.org]

  Dietary restrictions, diuretics, supplemental bicarbonate and decreasing medications associated with hyperkalemia are often unsuccessful. For many years, Kayexalate (sodium polystyrene sulfonate) has been the only available potassium-binding agent. [oatext.com]

• Insulin Increased

  Insulin increases potassium uptake into liver and muscle cells.13 A decrease in insulin levels, as may occur in type 2 diabetes or DKA, can cause a buildup of extracellular potassium.4 Also, serum hypertonicity from hyperglycemia results in water movement [mdedge.com]

  The insulin is usually given with an appropriate amount of glucose to prevent hypoglycemia following the insulin administration. Salbutamol (albuterol), a β2-selective catecholamine, is administered by nebuliser (e.g. 10–20 mg). [en.wikipedia.org]

• Erythrocytosis

  Other less common etiologies of elevated potassium levels in the serum is pseudohyperkalemia resulting from thrombocytosis, leukocytosis or erythrocytosis. [cdemcurriculum.com]

  […] preexisting burns and/or muscle trauma), Digoxin: inhibits the Na+/K+-ATPase → ↑ extracellular K+ concentration Extracellular release Pathological cell lysis Rhabdomyolysis Tumor lysis syndrome Hemolysis High blood cell turnover: e.g., thrombocytosis, erythrocytosis [amboss.com]

• Wide QRS Complex

  There is atrial-sensed, ventricular-paced rhythm with a rate of approximately 95 and a very wide QRS complex (about 220ms) but the QRS morphology is not typical for right or left bundle branch block. [emdocs.net]

  QRS complex changes (uniform widening) are often evident with increasingly worsening hyperkalemia. Loss of P waves then follows, ultimately leading to the formation of sine-waves - the fusion of wide QRS complexes with ST-T segments. [saem.org]

• Prolonged PR Interval

  Notes The classic ECG progression in hyperkalemia is: Peaked T waves Prolonged PR interval and flattening of the P wave Widening of the QRS Sine wave However. you cannot rely on the ECG to rule out significant hyperkalemia. [first10em.com]

  PR interval, wide QRS complex) as an alternative to 10 units of short acting insulin. [ncbi.nlm.nih.gov]

  PR interval AV block sine wave ventricular fibrillation asystole However, the sensitivity of ECG changes is low, and severe elevation can be accompanied by a normal ECG. [sharinginhealth.ca]

  ECG Examples Example 1 This ECG displays many of the features of hyperkalaemia: Prolonged PR interval. Broad, bizarre QRS complexes — these merge with both the preceding P wave and subsequent T wave. Peaked T waves. [lifeinthefastlane.com]

• Sinus Arrest

  A surface 12-lead electrocardiogram presented sinus arrest with peaked T-wave. [escardio.org]

  The authors hypothesized that poor coding of arrhythmias associated with extremes of hyperkalemia, such as sinus arrest and asystole, led to this discrepancy. [jasn.asnjournals.org]

• Peaking T Wave

  Tall, peaked T waves are typically the earliest manifestations of hyperkalemia and occur before changes to the QRS complex. In the absence of any other ECG findings, peaked T waves are rarely associated with life-threatening arrhythmias. [saem.org]

  This distinguishes peaked T waves of hyperkalemia from hyperacute T waves of early MI which tend to have a broader base T wave. Peaked T waves of Hyperkalemia. Note the amplitude of the T exceeds the amplitude of the R. [emergencymedicinecases.com]

  Demonstrates a ventricular junctional escape rhythm (41 beats/min), with absence of P waves and peaked T waves. [thepermanentejournal.org]

  A woman in her 40's was found down: Sinus rhythm with wide QRS at 133 ms and obvious Peaked T-waves with obvious hyperkalemia. But there is also significant ST elevation in V1-V3. Is there anterior STEMI? The K = 8.1. [hqmeded-ecg.blogspot.com]

• Absent A-Waves

  Role of inducing K + loss via the GI tract in the management of hyperkalemia Setting Recommendations Hyperkalemia with severe ECG changes (e.g. absent P waves, wide QRS complex) No role for inducing K + loss via GI tract Moderately severe hyperkalemia [doi.org]

  ECG: wide QRS complexes measuring 160-200 milliseconds a 60 bpm and absent P waves. Renal ultrasound: kidneys of normal size without ectasia. Chest x-ray: vascular redistribution. [revistanefrologia.com]

  Mild hyperkalemia: 5.5–6.4 mEq/L Tall, peaked T waves Moderate hyperkalemia: 6.5–8.0 mEq/L Lengthening of QRS interval (QRS complex widening) Widening and flattening of P wave, which eventually disappears Severe hyperkalemia: > 8.0 mEq/L Absent P wave [amboss.com]

  Peaked T waves. Example 5 Hyperkalaemia: Broad complex rhythm with atypical LBBB morphology. Left axis deviation. Absent P waves. Example 6 Hyperkalaemia: Sine wave appearance with severe hyperkalaemia (K+ 9.9 mEq/L). [lifeinthefastlane.com]

• Electrocardiogram Change

  Hemodialysis (HD) has been suggested as the definitive therapy for severe hyperkalemia in this population,although there is limited data regarding renal replacement options.We report a case of life-threatening hyperkalemia with electrocardiogram changes [ncbi.nlm.nih.gov]

  Coincident, baseline, and follow-up electrocardiograms were examined for quantitative and qualitative changes in the QRS and T waves as well as the official cardiology readings. [cjasn.asnjournals.org]

  Treatments involve inducing potassium loss.6-8 Electrocardiogram changes in hyperkalemia include a tall peaked T wave. [acls.com]

New treatments for hyperkalemia in development may offer better efficacy, tolerability and safety profiles than do existing approved treatments. [ncbi.nlm.nih.gov]

Treatment The urgency of treatment will depend primarily on whether ECG manifestations of hyperkalemia are present. [saem.org]

ACUTE TREATMENT Urgent treatment of hyperkalemia includes stabilizing the myocardium to protect against arrhythmias and shifting potassium from the vascular space into the cells. [aafp.org]

Hyperkalemia Microchapters Home Patient information Overview Historical Perspective Classification Pathophysiology Causes Differentiating Hyperkalemia from other Diseases Epidemiology and Demographics Risk Factors Screening Natural history, Complications and Prognosis [wikidoc.org]

Outlook / Prognosis What is the prognosis (outlook) for people who have hyperkalemia (high potassium)? Changes to your diet and medication often resolve mild cases of hyperkalemia. [my.clevelandclinic.org]

The prognosis is excellent for patients with mild transient hyperkalemia if the inciting cause is addressed and treated. [ncbi.nlm.nih.gov]

Prognosis The prognosis for specifically correcting hyperkalemia is excellent. However, hyperkalemia is usually caused by kidney failure, an often irreversible and eventually fatal condition. [medical-dictionary.thefreedictionary.com]

Although many causes of hyperkalemia exist, exogenous red blood cell transfusions are being recognized as the primary perioperative etiology. [ncbi.nlm.nih.gov]

This review article provides an overview of the physiology and the pathophysiology of potassium metabolism and hyperkalemia, the epidemiology of hyperkalemia, and its acute and chronic management. [ncbi.nlm.nih.gov]

Hyperkalemia Microchapters Home Patient information Overview Historical Perspective Classification Pathophysiology Causes Differentiating Hyperkalemia from other Diseases Epidemiology and Demographics Risk Factors Screening Natural history, Complications [wikidoc.org]

A more accurate determination of the frequency of hyperkalemia and of the clinical epidemiology of patients in whom this adverse event occurs could be very useful for planning strategies to prevent hyperkalemia and also for better managing this electrolyte [revportcardiol.org]

Ann Intern Med. 1993 Aug 15; 119 (4):296–301. [ PubMed ] [ Google Scholar ] DuBose TD., Jr Hyperkalemic hyperchloremic metabolic acidosis: pathophysiologic insights. [ncbi.nlm.nih.gov]

Hyperkalemia in heart failure is a condition that can occur with relative frequency because it is related to pathophysiological aspects of the disease, and favored by drugs that form the basis of chronic cardiac failure therapy. [imrpress.com]

The evidence needed to support a treatment claim (reduction in serum potassium) differs from that needed to support a prevention claim (preventing hyperkalemia to allow renin angiotensin aldosterone system inhibitor treatment). [ncbi.nlm.nih.gov]

Usually, hyperkalemia results from several simultaneous problems, including the following: Kidney disorders that prevent the kidneys from excreting enough potassium Drugs that prevent the kidneys from excreting normal amounts of potassium (a common cause [msdmanuals.com]

However, the beta 2 receptors also actiave sodium potassium ATPase channels also helping prevent hyperkalemia during periods of exercise. [youtube.com]

In a normal person, hyperkalemia from too much potassium in the diet is prevented by at least three types of regulatory processes. First, various cells and organs act to prevent hyperkalemia by taking up potassium from the blood. [medical-dictionary.thefreedictionary.com]