What is the best approach to manage hyperkalemia in an elderly non-diabetic patient with impaired renal function in the ER?

ER Management of Hyperkalemia 6.1 mmol/L with eGFR 56

For this elderly non-diabetic patient with moderate hyperkalemia (6.1 mmol/L) and stage 3 CKD (eGFR 56), immediately obtain an ECG and if any changes are present (peaked T waves, widened QRS, prolonged PR), administer IV calcium gluconate 15-30 mL over 2-5 minutes for cardiac membrane stabilization, followed by insulin 10 units with 50 mL of 50% dextrose IV plus nebulized albuterol 20 mg to shift potassium intracellularly. 1, 2

Initial Assessment

First, verify this is true hyperkalemia and not pseudohyperkalemia:

• Repeat the measurement with proper technique to exclude hemolysis, repeated fist clenching, or poor phlebotomy technique 1, 2
• Plasma potassium is typically 0.1-0.4 mEq/L lower than serum levels due to platelet release during coagulation 3

Obtain an ECG immediately - this is critical because ECG changes indicate urgent treatment regardless of the absolute potassium level 1, 2. However, recognize that ECG findings are highly variable and less sensitive than laboratory tests, so their absence does not exclude the need for treatment 3, 1

Classification and Treatment Urgency

Your patient has moderate hyperkalemia (6.0-6.4 mEq/L per classification) 1, 2. The urgency depends on:

• ECG changes (any changes = immediate treatment)
• Symptoms (muscle weakness, palpitations)
• Rate of rise in potassium

Acute Treatment Algorithm

Step 1: Cardiac Membrane Stabilization (if ECG changes present)

Administer IV calcium gluconate (10%): 15-30 mL over 2-5 minutes 4, 1, 2

• Onset: 1-3 minutes 3, 2
• Duration: 30-60 minutes (temporary effect) 2
• Critical caveat: Calcium does NOT lower potassium; it only stabilizes cardiac membranes 1, 2
• Can repeat in 5-10 minutes if no effect observed 3

Step 2: Shift Potassium Intracellularly

Administer all of the following simultaneously:

Insulin with glucose:

• Give 10 units regular insulin IV with 50 mL of 50% dextrose 4, 1, 5
• Onset: 15-30 minutes 4, 2
• Duration: 4-6 hours 4, 2
• Must give glucose with insulin to prevent hypoglycemia 1
• Can repeat every 4-6 hours if hyperkalemia persists, monitoring glucose and potassium every 2-4 hours 2

Nebulized albuterol:

• 20 mg in 4 mL nebulized 1, 2
• Onset: 30 minutes 3
• Duration: 2-4 hours 2
• Augments insulin effect 4, 6

Do NOT use sodium bicarbonate in this patient unless metabolic acidosis is documented (pH <7.35, bicarbonate <22 mEq/L) 1, 2. Bicarbonate only works in the presence of acidosis and takes 30-60 minutes to act 3, 2

Step 3: Remove Potassium from Body

With eGFR 56, this patient has adequate renal function for diuretic therapy:

• Administer furosemide 40-80 mg IV to increase urinary potassium excretion 2
• Loop diuretics promote potassium excretion by increasing distal sodium delivery to renal collecting ducts 2

Hemodialysis is the most effective method for potassium removal but is reserved for severe cases unresponsive to medical management, oliguria, or end-stage renal disease 3, 4, 2

Identify and Address Underlying Causes

Review medications immediately:

• ACE inhibitors/ARBs 1, 2
• Mineralocorticoid antagonists (spironolactone, eplerenone) 1, 2
• NSAIDs 1, 2
• Potassium-sparing diuretics 2
• Beta-blockers 1, 2
• Trimethoprim, heparin 2
• Potassium supplements or salt substitutes 2

For this elderly patient with CKD, do NOT automatically discontinue RAAS inhibitors - these provide mortality benefit and slow CKD progression 2. Instead, plan to use potassium binders for chronic management 2

Disposition and Follow-up

Monitoring in ER:

• Recheck potassium every 2-4 hours after treatment 2
• Continuous cardiac monitoring if ECG changes were present 6
• Monitor glucose closely to avoid hypoglycemia from insulin 1, 2

Discharge planning (if potassium normalizes and patient stable):

• Initiate newer potassium binder: patiromer (8.4 g once daily) or sodium zirconium cyclosilicate (10 g three times daily for 48 hours, then 5-15 g daily) 2
• These agents allow continuation of life-saving RAAS inhibitors 2
• Recheck potassium within 1 week 1, 2
• Avoid older agent sodium polystyrene sulfonate (Kayexalate) due to delayed onset and risk of bowel necrosis 2

Critical Pitfalls to Avoid

• Do not rely solely on ECG - absence of changes does not exclude serious hyperkalemia 3, 1
• Remember that calcium, insulin, and beta-agonists only temporize - they do not remove potassium from the body 1, 2
• Always give glucose with insulin to prevent hypoglycemia 1
• Do not use bicarbonate without documented metabolic acidosis 1, 2
• Do not discontinue RAAS inhibitors reflexively in CKD patients - use potassium binders instead to maintain renal protection 2