Emergency Management of Hyperkalaemia Paediatric Intensive Care Unit
Transcription
Emergency Management of Hyperkalaemia Paediatric Intensive Care Unit
Emergency Management of Hyperkalaemia Paediatric Intensive Care Unit Royal Hospital for Sick Children Emergency Mangement Hyperkalaemia Author: A McKie, D Ellis Date of Review: Oct 2012 of Version: 1 Page 1 of 19 Authorised by: PICU Guideline Group Q-Pulse Ref: YOR-PICU-007 Issue Date: Oct 2010 Contents 1. 2. 3. 4. 5. 6. 7. 8. Methodology Background Management Review Monitoring Implementation References Treatment Algorithm Page Number(s) 2-3 3-8 9-14 14 14 15 15-16 17 1 Methodology 1. Rationale/Purpose/Objective - to standardise the emergency management of hyperkalaemia in children within the PICU provide an evidence base for the proposed guideline provide background information to allow the practitioner to understand the principles of the therapy - 2. Scope - emergency management of hyperkalaemia - this guideline is intended for the management of hyperkalaemia in patients in paediatric critical care. Transfer to an HDU or PICU environment should be considered depending on where the patient is located. It may be appropriate to initiate and complete management within the A+E Department or on the renal ward. Renal patients may have their own treatment algorithm. Chronic renal patients should be discussed with both consultant renal and consultant PICU staff as a matter of urgency. If there are ECG abnormalities then follow this emergency protocol. 3. Roles and Responsibilities - critical care personnel managing a child who develops hyperkalaemia on the critical care unit at Yorkhill Chidren’s Hospital Glasgow. 4. Evidence - constructed after review of standard textbooks, pub med and Google scholar search (interrogation of quoted references), using the search terms, hyperkalaemia or hyperkalemia, therapy or treatment or management or guideline. Only articles in English were reviewed. Evidence available is mostly level 3 and 4. Emergency Mangement Hyperkalaemia Author: A McKie, D Ellis Date of Review: Oct 2012 of Version: 1 Page 2 of 19 Authorised by: PICU Guideline Group Q-Pulse Ref: YOR-PICU-007 Issue Date: Oct 2010 This guideline is proposed acknowledging that • there is little evidence base • there is significant variation in how drugs are used, despite acceptance of their efficacy • there is a lack of agreement on treatment thresholds. Any chosen threshold value for commencing treatment is by definition arbitrary. 5. Methods - prior to publication the proposed guideline was reviewed by PICU consultants, the ward pharmacist and nursing education staff. 2. Background Potassium is a mostly intracellular cation with approximately 98% of the total being within the intracellular fluid (ICF) compartment (mainly muscle) and only 2% in the extracellular fluid (ECF). This ratio of ECF:ICF potassium is a primary determinant of resting membrane potential in all electrically active cells and a small absolute change in extracellular potassium can alter the resting membrane potential of these cells. This can have dramatic effects on cell function including altering myocardial cell conduction velocity, repolarisation, preventing normal muscle contraction and nerve functioning. Therefore the body maintains tight control of extracellular potassium in a variety of ways including altering renal and gut excretion and the flux of potassium into or out of the intracellular compartment (mainly via the sodium potassium pump). Potassium is retained in cells by a negative voltage, generated by the active transport of Na out of cells by Na/K-ATPase. Both insulin and catecholamines cause a potassium shift into cells. Insulin stimulates the NA/H exchanger, the intracellular Na is now available for exchange with Potassium via Na/K-ATPase, whilst catecholamines directly activate the Na/K-ATPase via adenlate cyclase activation, which in turn stimulates cAMP which is utilised by Na/K-ATPAse . The concentration gradients of Na Emergency Mangement Hyperkalaemia Author: A McKie, D Ellis Date of Review: Oct 2012 of Version: 1 Page 3 of 19 Authorised by: PICU Guideline Group Q-Pulse Ref: YOR-PICU-007 Issue Date: Oct 2010 and K produce an electrical potential across the myocyte leading to a resting membrane potential of -90mV. As ECF K content increases the concentration gradient across the myocyte decreases and the resting membrane potential is lowered (Fig.1) The rate of rise of phase 0 of the action potential (Vmax) is directly proportional to the value or the resting membrane potential at the onset of phase 0 (Fig.2). The decrease in Vmax slows conduction and prolongs membrane depolarisation. In addition the duration of the action potential is decreased. Initially hyperkalaemia increases excitability by shifting the resting membrane potential to a less negative value i.e. nearer to the threshold potential. Subsequently Vmax continues to decrease and myocyte depression occurs. Fig. 1 Fig. 2 Hyperkalaemia is defined as a potassium level greater than the upper limit of normal for age. Normal serum (extracellular) potassium levels are age dependant in children, within the range 3.5 to 5 mEq/l (mmol/l), but can be as high as 6.mEq/L in premature infants [1]. There is no universally accepted definition for mild, moderate, or severe hyperkalaemia. [2] Some authors suggest mild to be 5.5 to 6 moderate 6.1 to 7, and severe hyperkalaemia to be greater than 7mEq/l (mmol/l) [3]. Hyperkalaemia is not uncommon with some reports suggesting up to 10% of hospitalised adult patients being affected [4], though in reality the incidence in the paediatric population is unknown. It can be a serious and potentially life threatening condition and may necessitate urgent intervention that often precedes complete investigation of the cause. Unfortunately, serum potassium does not always correlate with severity of the clinical picture and other factors such as rapidity of rise, acid-base status and pre-morbid condition of the patient also need to be considered. Classic electrocardiogram changes associated with hyperkalaemia are well described in the literature [5]. However, it is important to appreciate that the relationship between serum potassium and ECG changes varies between individuals particularly in mild to moderate elevation of potassium. In some patients with severe hyperkalaemia, particularly of a more chronic nature, minimal ECG changes may be evident [5] [6]. As such ECG changes should not be taken in isolation to determine Emergency Mangement Hyperkalaemia Author: A McKie, D Ellis Date of Review: Oct 2012 of Version: 1 Page 4 of 19 Authorised by: PICU Guideline Group Q-Pulse Ref: YOR-PICU-007 Issue Date: Oct 2010 management and it is important to note that a normal ECG should not preclude need for treatment Aetiology of hyperkalaemia The most common cause of hyperkalaemia in paediatric practice is pseudo-hyperkalaemia or a spuriously elevated result. The clearest indicators of probable spurious hyperkalaemia are clinical context and renal function [7]. Therefore, if the patient has normal renal function and no risk factors for hyperkalaemia it is likely that the result is spurious. (1) Pseudo-hyperkalaemia may be due to: • • • • • • • • • • Excessive tourniquet time, fist clenching Squeezing related to capillary blood letting Sampling proximal to a line taking potassium containing fluid Sampling a line with potassium containing fluid Sampling from a central line lumen distal to lumen containing potassium infusate Vigorous shaking of sample Contamination of sample by potassium EDTA from FBC bottle Injection of serum through narrow bore needle into sample bottle Delay in processing of sample Cold storage/transport of sample (big issue in primary care) Some of these situations cause red cell haemolysis. This “in vitro” haemolysis causing potassium to leach out of red cells can usually be detected in the laboratory by a pinkish tinge to the serum. True hyperkalaemia is due to a combination of increased intake, transcellular shift and decreased excretion. (2) Renal dysfunction or renal tract obstruction: This can be chronic and includes patients on various dialysis regimens, or acute in which case it may not be known at presentation that the patient has renal dysfunction. (3) Conditions that cause cellular potassium leakage including: • • • • • Marked leucocytosis/leukaemia Thrombocytosis (potassium released during clot formation-plasma levels normal serum levels raised) Hereditary and acquired red cell disorders causing in vivo haemolysis Tumour lysis syndrome Trauma, burns, surgery, crush injury, rhabdomyolysis Emergency Mangement Hyperkalaemia Author: A McKie, D Ellis Date of Review: Oct 2012 of Version: 1 Page 5 of 19 Authorised by: PICU Guideline Group Q-Pulse Ref: YOR-PICU-007 Issue Date: Oct 2010 • Compartment syndrome (4) Causes of increased potassium intake or reduced excretion including: • • • • • • • Excessive potassium in diet – usually able to be accommodated for by increased secretion by normally functioning kidneys Potassium sparing diuretics e.g. spironolactone Potassium containing medications such as potassium supplementation, lo salt (replaces sodium salt with potassium), trimethoprim, Movicol, Fybogel Drugs that interfere with the renin-angiotensin system: heparin, NSAID’s, ACE inhibitors, angiotensin II blockers Iatrogenic excess e.g. IV fluid / TPN Blood transfusion (risk increases with irradiation and age of blood) Rapid administration of blood via hand held syringes and small gauge needles (5) Causes of transcellular shift of potassium out of cells: • • • • • Acidosis * Some drugs e.g. β-blockers, suxamethonium , propofol Digoxin toxicity Insulin deficiency Cessation of β-adrenergic agonists, followed by leaching of K+ out of cells * Suxamethomium can cause a transient rise in serum potassium of 0.51mmol/l for up to half an hour [8][9][10] (6) Rare conditions such as: • • • Hyperkalaemic familial periodic paralysis Disorders of adrenal insufficiency, hypoaldosteronism and Addison’s (inadequate aldosterone driven excretion of potassium) Malignant hyperthermia Patient Assessment Hyperkalaemia may be entirely asymptomatic and detected coincidentally during blood testing for another reason or the patient may have symptoms such as tiredness, nausea, vomiting, muscle weakness, palpitations or very rarely flaccid paralysis. Even in the absence of symptoms a high potassium level particularly in conjunction with supportive ECG changes is a medical emergency. A Emergency Mangement Hyperkalaemia Author: A McKie, D Ellis Date of Review: Oct 2012 of Version: 1 Page 6 of 19 Authorised by: PICU Guideline Group Q-Pulse Ref: YOR-PICU-007 Issue Date: Oct 2010 totally asymptomatic patient can rapidly progress to develop a life threatening arrhythmia in this condition. It is therefore vital that the diagnosis is reached rapidly and that appropriate therapeutic measures are undertaken immediately. As already mentioned in paediatric practice spuriously high potassium levels are a regular occurrence often due to difficulty obtaining blood samples. However these “possibly spurious” results must never simply be ignored, and should always be repeated. The clinician should determine whether the patient has any signs of renal dysfunction or if any other features in the history or examination make him at risk of hyperkalaemia (e.g. drug history, known diabetic, patient receiving chemotherapy). Indicators of renal function including urea and creatinine will usually be available concurrent with the potassium result to provide some guidance. In most cases of unexpected hyperkalaemia it is prudent to rapidly repeat the test whilst preparing treatment, though treatment should not be delayed awaiting the result, especially if there are ECG changes supportive of elevated potassium [11]. In many acute paediatric assessment areas there is now the ability to measure a potassium level on a blood gas analyser which will take a matter of minutes. Whilst a specimen should also be sent to the laboratory for confirmation, therapy if needed should not be withheld awaiting the formal laboratory result. ECG Monitoring: Whilst confirming the diagnosis and during therapy, the patient should have continuous ECG monitoring, to detect any of the classic changes associated with hyperkalaemia. Whilst there is a recognised progression of ECG changes from mild through to severe hyperkalaemia, there is a poor correlation between ECG changes and serum potassium concentration, and the progression of rhythm abnormalities is unpredictable in any individual. ECG changes are dependent on both the absolute value and the rate of increase of potassium levels. Some patients with severe hyperkalaemia may have no identifiable ECG changes and others may have changes at surprisingly low potassium levels. The absence of ECG changes in cases of moderate or severe hyperkalaemia does not obviate the need for therapy. The presence of ECG changes, even in mild hyperkalaemia, should encourage prompt and aggressive treatment. Emergency Mangement Hyperkalaemia Author: A McKie, D Ellis Date of Review: Oct 2012 of Version: 1 Page 7 of 19 Authorised by: PICU Guideline Group Q-Pulse Ref: YOR-PICU-007 Issue Date: Oct 2010 Early ECG changes in mild hyperkalaemia (>5.5mEq/l) include peaking or tenting of the T-wave. Thereafter as levels exceed 6.5mEq/l there is reduction in conduction velocity resulting in prolonged PR interval and progressive widening of the QRS complex and nodal and ventricular arrhythmias may occur. Ultimately the p-waves disappear and the QRS complexes combine with the T-wave to form a sine-wave appearance with ventricular fibrillation or asystole ensuing. Investigations Regular monitoring of serum potassium, electrolytes, glucose and blood gas are useful especially as hyperkalaemia is frequently associated with acidosis and hyperglycaemia. In some cases it may be useful to perform: • • • • • Full blood count with differential and film to look for haemolysis, leucocytosis and thrombocytosis Creatinine kinase in cases of possible tissue injury, trauma, burns Urinary potassium excretion Bilirubin, reticulocytes and haptoglobin in suspected haemolysis Renal ultrasound if suggestion of renal dysfunction or obstruction Emergency Mangement Hyperkalaemia Author: A McKie, D Ellis Date of Review: Oct 2012 of Version: 1 Page 8 of 19 Authorised by: PICU Guideline Group Q-Pulse Ref: YOR-PICU-007 Issue Date: Oct 2010 These investigations depend upon the individual clinical situation and must never delay acute treatment once it is deemed necessary. 3. Management Airway, Breathing, Circulation. Repeat serum potassium should be ordered urgently, especially if hyperkalaemia is an unexpected or isolated finding and there are no ECG signs of hyperkalaemia, to exclude pseudohyperkalaemia. This can be run on the gas machine and should not preclude starting preparation of definitive therapy. Hypoxia potentiates the risk of cardiac dysrhythmia, so all patients (unless there is an associated cardiac lesion requiring low FiO2) should be administered oxygen. The response of an individual patient to any of the following proposed therapies is unpredictable, so frequent repeated monitoring of potassium is mandatory. ECG monitoring should be continuous once hyperkalaemia is suspected and treatment is commenced. Emergency treatment is required in any patient with ECG changes, is symptomatic or who has a true potassium level above 6.5mmol/l regardless of ECG appearance. Between 6 and 6.5mmol/l calcium may be withheld at the discretion of senior medical staff but other therapy should be commenced. Even lower levels of hyperkalaemia may require treatment particularly in the setting of a rapid or acute rise when it is less well tolerated. Arrhythmia control is difficult without lowering the serum potassium level. Ideally calcium and glucose 50% should be administered centrally. If central access is unavailable then it may be appropriate to give larger volumes of a more dilute concentration. Preparation time and risk of injuries secondary to extravasation must be weighed against the risk of cardiac instability. Bradycardia secondary to hyperkalaemia presents a conundrum and mandates the PICU consultant being informed. It is unlikely to resolve without correcting the hyperkalaemia but therapy with calcium salts may Emergency Mangement Hyperkalaemia Author: A McKie, D Ellis Date of Review: Oct 2012 of Version: 1 Page 9 of 19 Authorised by: PICU Guideline Group Q-Pulse Ref: YOR-PICU-007 Issue Date: Oct 2010 exacerbate the bradycardia, or produce AV block and asystole. The effect of atropine and phenylepherine is blunted. Pacing may prove ineffective because of increased stimulation thresholds secondary to hyperkalaemia. Standby ECMO may have to be considered. There are four components to the acute management of hyperkalaemia: 1. Antagonize the membrane toxic effects of potassium 2. Promote rapid cellular uptake of potassium 3. Remove potassium directly from the body 4. Discontinue source of exogenous potassium (drugs, fluids) 1. Antagonize the membrane toxic effects of potassium Calcium salts antagonise the effects of hyperkalaemia on the cardiac membrane. They increase the threshold potential, restoring the gap between the resting membrane potential and the threshold potential. In addition it restores Vmax at higher resting membrane potentials, normalising the rate of myocyte depolarisation, and normalises impulse propagation in the SA and AV nodes. There is no effect on serum potassium levels and other therapies that lower serum potassium levels should be administered concomitantly. Either 10% calcium gluconate or 10% calcium chloride can be used depending on availability. Calcium chloride has 3 times more elemental calcium than an equal volume of calcium gluconate, so if volume administration/tolerance is a problem then theoretically calcium chloride may be preferred. Calcium chloride is more likely to cause extravasation injury. The benefits of this treatment are usually evident with improvement in ECG changes within a few minutes and last 30-60 minutes. • • IV Calcium Gluconate 10%, 0.5 -1ml/kg (0.11-0.22mmol/kg) [max 4.4mmol] IV Calcium Chloride 10%, 0.2ml/kg (0.14mmol/kg) [max 1.4mmol] Administer over 5minutes and repeat as necessary after 5 minutes, if ECG fails to improve or deteriorates. The initial dose can be given over 1-3 minutes if life threatening arrhythmias or sine wave ECG changes are present. (Stop infusion if bradycardia develops) Administration should be over 30 minutes if the patient is on digoxin, to avoid hypercalcaemia that may potentiate the myocardial toxicity of digoxin. 2. Promote rapid cellular uptake of potassium These interventions buy time for more definitive therapy but they do not remove potassium from the body. Beta-blockers and digoxin may reduce the effectiveness of insulin-glucose and beta-2 agonists. Emergency Mangement Hyperkalaemia Author: A McKie, D Ellis Date of Review: Oct 2012 of Version: 1 Page 10 of 19 Authorised by: PICU Guideline Group Q-Pulse Ref: YOR-PICU-007 Issue Date: Oct 2010 a) Insulin Insulin stimulates the Na-K ATP pump to promote intracellular potassium uptake. It is thought to recruit intracellular pump components into the cellular membrane and increase availability of intracellular Na by its effect on the Na/H exchanger. It is indicated in every case of hyperkalaemia that requires treatment [11]. Insulin is co administered with glucose to prevent hypoglycaemia. Blood glucose should be checked at the end of the infusion and then every 15 minutes for an hour after administration as delayed hypoglycaemia is common. The onset of action is around 15 minutes and the effect lasts for over 1 hour. Potassium levels have been shown to fall by up to 0.5mmol/l in 20minutes and 1mmol/l by an hour, so it is an effective temporising manoeuvre [11] [14]. Dosing can be repeated after 30 minutes. The effect lasts up to 4 hours. • 2ml/kg 50% dextrose (1g/kg) and 0.1units/kg of fast acting Insulin over 5-10 minutes (mixed in same syringe) [13]. Theoretically one could give a dextrose load alone as this will increase the child’s own insulin production and promote intracellular uptake of potassium, however the potassium lowering effect is likely to be greater if glucose and insulin are used in combination. Also the endogenous insulin response may be inadequate and the resultant hypertonic state may exacerbate hyperkalaemia due to solvent drag with efflux of water from the intracellular to extracellular compartment. Glucose may not need to be given if the serum glucose is > 16mmol/dl, this should be discussed with the consultant. b) β-adrenergic agonist. Several paediatric studies, although small, advocate the use of salbutamol as a safe and effective measure to temporarily reduce serum potassium levels [15][16][17]. Salbutamol, (IV or nebulised), indirectly, via cyclicAMP, stimulates the cell membrane Na-K ATP pump in hepatic and muscle cells to promote cellular potassium uptake. In addition it increases endogenous insulin secretion. This is secondary to hepatic gluconeogenesis derived hyperglycaemia, and is not a dominant mechanism for reducing potassium levels Salbutamol is equally effective in diabetic and non diabetic patients and in diabetic patients where cpeptide levels are not elevated. [18] There is controversy regarding use of salbutamol as some studies suggest it to be arrythmogenic at high dose. There is also a significant proportion of patients (up to 20-40%) who are non-responders to this treatment with Emergency Mangement Hyperkalaemia Author: A McKie, D Ellis Date of Review: Oct 2012 of Version: 1 Page 11 of 19 Authorised by: PICU Guideline Group Q-Pulse Ref: YOR-PICU-007 Issue Date: Oct 2010 no or minimal reduction in serum potassium. The mechanism is unclear and unpredictable. For this reason it is recommended that salbutamol not be used alone in the treatment of hyperkalaemia. • • 4mcg/kg IV salbutamol over 5 minutes repeated as required or 2.5mg (<5 years) or 5mg (>5years) nebulised salbutamol It is unlikely to be effective if the patient is on beta blockade for renal failure associated hypertension. Both of these have been proven to be effective in reducing potassium levels by up to 1.4mmol/l if intravenous route used and up to 1mmol/l if nebulised. The onset of action is around 30 minutes lasting 2-3 hours. [15][16][17] A few studies suggest a synergistic effect in using salbutamol combined with insulin/glucose with greater reduction in potassium level than either used alone. [14][18]. They are equally efficacious in lowering plasma potassium. The effect of salbutamol is delayed slightly relative to insulin but this is likely to be secondary to the mode of administration ie slow nebulisation as opposed to IV bolus. In addition salbutamol may offset the hypoglycaemic effect of insulin. This is consistent with β2-agonistic activity on the liver where stimulation of gluconeogenesis and glycogenolysis occurs. [18] A Cochrane review suggests that Dextrose/Insulin and salbutamol are the first line therapies most supported by evidence, and that a combination of the two therapies may be more effective than either alone. [19] There is no statistically significant difference between the effectiveness of intravenous, nebulised or inhaled salbutamol in the limited number of studies to date. It is likely to be easier and quicker to nebulise a patient in the short term, though in the emergency situation in a non ventilated patient, delivery may be erratic. Under such circumstances intravenous follow up can be considered. Salbutamol can cause a transient release of potasssium from liver causing a small increase in potassium c) Sodium Bicarbonate The use of sodium bicarbonate is no longer advocated in the absence of significant metabolic acidosis. It has little effect in lowering serum potassium levels within 60 minutes when studied in adult populations with chronic renal failure [20][21]. It may offer slight reduction in potassium levels over a period of several hours particularly on the background of proven metabolic acidosis with pH < 7.2 [22]. Acidosis may inhibit the physiologic response to catecholamines and insulin, and using bicarbonate in conjunction with insulin or salbutamol may be of some benefit. There is a risk of hypocalcaemia because alkalosis decreases the levels of ionised calcium, which may be poorly tolerated and potentiate arrhythmias. It should not be administered at the same time via the same line as calcium or calcium bicarbonate may precipitate. Emergency Mangement Hyperkalaemia Author: A McKie, D Ellis Date of Review: Oct 2012 of Version: 1 Page 12 of 19 Authorised by: PICU Guideline Group Q-Pulse Ref: YOR-PICU-007 Issue Date: Oct 2010 It is unclear whether any reduction in potassium is due to intracellular shift of potassium with alkalinisation or if it is related to the large hypertonic load from large quantities of sodium in the preparation with ensuing fluid shifts. Regardless, the significant side effects such as volume and sodium overload, particularly in patients with renal dysfunction, along with the knowledge that it is poorly effective, probably preclude its use in most situations. The evidence is sufficiently inconclusive in cases of co-existing acidosis that some centres continue to use bicarbonate to manage hyperkalaemia in combination with other therapy. [23]. • 3. 1mmol/kg over 10 minutes (repeat in 10 minutes as required; monitor blood gases to maintain pH <7.55 Remove potassium directly from the body a) Cation exchange resins e.g. calcium resonium and Resonium A – the degree of benefit of these treatments in hyperkalaemia remains controversial. Cation exchange resins remove potassium directly from the body through the gut mucosa of the large bowel and ileum. Approximately one gram of resin exchanges 1mmol sodium or 2mmol calcium for 1mmol of potassium. This potassium is then bound by the resin in the intestinal lumen and excreted. The onset of action is slow, in the order of 1-2 hours, with peak of 4-6 hours so the temporising steps in point 2 must be undertaken in the first instance. The resins can be administered rectally or orally. The preferred route is oral (except in neonates) if administered rectally the resin should be mixed with methylcellulose and retained for at least 60 minutes. Recommended doses are: 250mg/kg (max 15g) 3-4 times per day orally or rectally, repeated every 6-8 hours if required for children over 1 month of age. [13] The resin must not be combined with fruit juices as they contain high levels of potassium. If the rectal route is used the colon must be irrigated 6-12 hourly to prevent faecal impaction. Side effects include rectal mucosal irritation and ulceration, faecal impaction, constipation and rarely bowel perforation. Hypercalcaemia may occur especially in patients on dialysis. The data regarding the effectiveness of exchange resins is conflicting. It is possible to excrete up to 12 mmol/l potassium via the gastro-intestinal tract in healthy adults however this is limited by stool volume. This is especially pertinent in a paediatric population who obviously have much lower stool volumes. Some authors also suggest that resins do not contribute to faecal potassium excretion above the effect of laxatives alone [24] Emergency Mangement Hyperkalaemia Author: A McKie, D Ellis Date of Review: Oct 2012 of Version: 1 Page 13 of 19 Authorised by: PICU Guideline Group Q-Pulse Ref: YOR-PICU-007 Issue Date: Oct 2010 In spite of these reservations the GAIN (Guidelines and Audit Implementation Network) in Northern Ireland still advocate the use of exchange resins to remove potassium from the gut though accept that other measures must be used in the first instance due to delayed onset of action [4] b) Loop diuretic e.g. Furosemide These drugs increase urine flow and delivery of sodium to distal tubular potassium excreting sites. This is likely to be less effective in patients with renal dysfunction who may have limited response to diuretics c) Haemodialysis This is the definitive method of removal of potassium from the body. It is used in cases of severe hyperkalaemia or when other treatments have failed to provide a sustained reduction in potassium. Serum potassium can be lowered by 1-1.5mmol/l for every hour of dialysis although some rebound is expected on completion of dialysis. Rapid liaison with tertiary paediatric nephrologists or intensive care specialists capable of providing this treatment modality is necessary when potassium is very high, other treatments appear to be failing, or if ongoing tissue damage and continued release of intracellular potassium is expected. Treatment that causes intracellular shifts of potassium decreases the efficacy of potassium clearance by dialysis because they decrease the concentration gradient between plasma and the dialysate. It may be necessary to redialyse this patient group as the effects of β agonists’ wear of and potassium returns to the extracellular compartment. [25] Potassium free dialysate will maximise potassium clearance. Long term management Review diet and reduce potassium intake - in normal individuals the kidneys can adapt to excrete excess potassium intake however this is not the case if there is kidney dysfunction or the patient is taking medications that alter potassium excretion such as potassium sparing diuretics. Notably “Lo salt” replaces sodium salt with potassium salt and may be an occult contributory factor. Review of medications and fluid/nutrition prescriptions - potassium sparing diuretics, ACE inhibitors, heparin, trimethoprim and other potassium containing antibiotics, Fybogel and Movicol all act by various mechanisms to increase extracellular potassium levels. Haemodialysis – the definitive treatment of hyperkalaemia. Particularly useful in cases of acute or chronic renal failure or when other treatments have failed and the potassium level remains high. If a potassium free diasylate is used, serum potassium may decrease as much as 1.2 to 1.5 mmol/l per hour however there will be rebound in potassium levels on Emergency Mangement Hyperkalaemia Author: A McKie, D Ellis Date of Review: Oct 2012 of Version: 1 Page 14 of 19 Authorised by: PICU Guideline Group Q-Pulse Ref: YOR-PICU-007 Issue Date: Oct 2010 completion of dialysis. Peritoneal dialysis is poorly effective at lowering serum potassium levels in comparison. Longer term treatment must be individual patient based, dependent upon the cause of the hyperkalaemia. It may simply be a case of dietary restriction or alteration to drug regime though in other cases, such as hypoaldosteronism, mineralocorticoid replacement therapy would be necessary or haemodialysis may be required for renal dysfunction. 4. Review: This guideline should be reviewed every 2 years from date of approval 5. Monitoring An audit of adherence to the guidelines can be performed. 6. Implementation plan - Education and training for nursing staff - Education for PICU trainees - Guideline to be put on electronic clinical information system Emergency Mangement Hyperkalaemia Author: A McKie, D Ellis Date of Review: Oct 2012 of Version: 1 Page 15 of 19 Authorised by: PICU Guideline Group Q-Pulse Ref: YOR-PICU-007 Issue Date: Oct 2010 7. References 1. Shaffer SG, Kilbride HW, Hayen LK, Meade VM, Warady BA. Hyperkalemia in Very Low Birth Weight Infants. J Pediatr, 1992;121:275-9. 2. Brenner: Brenner & Rector's The Kidney, 7th ed. Copyright © 2004 Saunders, An Imprint of Elsevier 3. Mandal AK. Hypokalemia and hyperkalemia. Med Clin North Am 1997;81:611–39 4. Guidelines for the Treatment of Hyperkalaemia in Adults GAIN (Guidelines and Audit Implementation Network- Northern Ireland) December 2008 5. Webster A, Brady W, Morris F. Recognising Signs of Danger: ECG Changes Resulting From an Abnormal Serum Potassium Concentration. Emerg Med J 2002;19:74–77 6. Martinez-Vea A, Bardaji A, Garcia C, Oliver J A. Severe Hyperkalemia With Minimal Electrocardiographic Manifestations. Journal of Electrocardiology1999 32 1 45-49 7. Stuart W, Smellie A. Spurious Hyperkalaemia. BMJ 2007;334:693-5 8. Day S. Plasma Potassium Changes Following Suxamethonium And Suxethonium In Normal Patients And In Patients In Renal Failure Br.J. Anaesth. 1976;48: 1011-15 9. List W F. Serum Potassium Changes During Induction Of Anaesthesia. Brit. J. Anaesth. 1967;39: 480-484 10. Weintraub H D, Heisterkamp D V, Cooperman L H. Changes In Plasma Potassium Concentration After Depolarizing Blockers In Anaesthetized Man. Brit. J. Anaesth. 1969;41:1048-105 11. Ahee P, Crowe AV. The Management Of Hyperkalaemia In The Emergency Department. J Accid Emerg Med 2000;17:188–191 12. Noyan A, Anarat A, Pirti M, et al. Treatment Of Hyperkalemia In Children With Intravenous Salbutamol. Acta Paediatr Jpn 1995;37:355–7 13. Martin J (ed) BNF for Children 2010. London: Pharmaceutical Press 2010 14. Lens XM, Montoliu J, Cases A, et al. Treatment Of Hyperkalemia In Renal Failure: Salbutamol V Insulin. Nephrol Dial Transplant 1989;4:228– 32 Emergency Mangement Hyperkalaemia Author: A McKie, D Ellis Date of Review: Oct 2012 of Version: 1 Page 16 of 19 Authorised by: PICU Guideline Group Q-Pulse Ref: YOR-PICU-007 Issue Date: Oct 2010 15. Murdoch IA, Dos Anjos R, Haycock GB. Treatment Of Hyperkalemia With Intravenous Salbutamol. Arch Dis Child. 1991;66:527-8 16. Kemper MJ, Harps E, Hellwege HH, et al. Effective Treatment Of Acute Hyperkalaemia In Childhood By Short term Infusion Of Salbutamol. Eur J Pediatr 1996;155:495–7 17. McClure RJ, Prasad VK, Brocklebank JT. Treatment Of Hyperkalaemia Using Intravenous And Nebulised Salbutamol. Arch Dis Child 1994;70:126–8 18. Allon M, Copkney C. Albuterol And Insulin For Treatment Of Hyperkalemia In Hemodialysis Patients. Kidney Int 1990;38:869–72 19. Mahoney BA, Smith WAD, Lo D, Tsoi K, Tonelli M, Clase C. Emergency Interventions For Hyperkalaemia (Review). Cochrane Collaboration July 2009 20. Allon M, Shanklin N. Effect Of Bicarbonate Administration On Plasma Potassium In Dialysis Patients: Interactions With Insulin And Albuterol. Am J Kidney Dis 1996;28:508–14 21. Blumberg A, Weidmann P, Shaw S, et al. Effect Of Various Therapeutic Approaches On Plasma Potassium And Major Regulating Factors In Terminal Renal Failure. Am J Med 1988;85:507–12 22. Allon M. Treatment And Prevention Of Hyperkalemia In Endstage Renal Disease. Kidney Int 1993;43:1197–209 23. Kamel K S, Wei C. Controversial Issues In The Treatment Of Hyperkalaemia. Nephrol Dial Transplant 2003; 18: 2218–2221 24. Gruy-Kapral C, Emmett M, Santa Ana CA. Effect Of Single Dose ResinCathartic Therapy On Serum Potassium Concentration In Patients With End-Stage Renal Disease. J Am Soc Nephrol 1998; 9: 1924–1930 25. Allon M, Shanklin N. Effect Of Albuterol Treatment On Subsequent Dialytic Potassium Removal. Am J Kidney Dis 1995;26:607-1 Emergency Mangement Hyperkalaemia Author: A McKie, D Ellis Date of Review: Oct 2012 of Version: 1 Page 17 of 19 Authorised by: PICU Guideline Group Q-Pulse Ref: YOR-PICU-007 Issue Date: Oct 2010 Emergency Mangement Hyperkalaemia Author: A McKie, D Ellis Date of Review: Oct 2012 of Version: 1 Page 18 of 19 Authorised by: PICU Guideline Group Q-Pulse Ref: YOR-PICU-007 Issue Date: Oct 2010 Hyperkalaemia Algorithm (PICU) K+ > 5.5 mmol/l Regular Monitoring During Therapy (Genuine Result) A,B,C, Oxygen, cardiac monitoring Consider and address precipitating factors Stop potassium containing fluids Does Patient Have Chronic Renal Failure? Yes No Asymptomatic and Normal ECG Symptomatic or abnormal ECG Discuss with renal and ICU consultant , follow patient protocol • Stabilise Cardiac Membrane • K+ ≥6mmol/l or abnormal ECG or symptomatic IV Calcium Gluconate 10%, 0.5 -1ml/kg (0.11-0.22mmol/kg) [max 4.4mmol] or IV Calcium Chloride 10%, 0.2ml/kg (0.14mmol/kg) [max 1.4mmol] K+ <6mmol/l and normal ECG and asymptomatic Discuss with consultant over 2-3 minutes (can repeat after 10 mins) • Shift Potassium Into Cells • IV glucose 50% 2ml/kg + 0.1 units/kg Actrapid insulin over 5-10 minutes (mixed in same syringe) AND Nebulised salbutamol: <5Years 2.5mg, >5 years 5mg Or IV salbutamol 4mcg/kg over 5minutes Consider Sodium Bicarbonate 8.4%, 1mmol/kg if pH < 7.2 • IV Furosemide 0.5mg/kg • Calcium Resonium 250mg Oral or PR 6-8 hourly Remove Potassium From Body CONSIDER HAEMODIALYSIS HAEMOFILTRATION