Podcasts · Core EM - Emergency Medicine Podcast

Episode 189: Hyperkalemia 2.0

· Episode 189

Episode Episode 189: Hyperkalemia 2.0

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We revisit the topic of Hyperkelamia to update our prior episode from 2015 (pre-Lokelma)

Hosts: Brian Gilberti, MD Jonathan Kobles, MD

https://media.blubrry.com/coreem/content.blubrry.com/coreem/Hyperkalemia.mp3

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Show Notes

Introduction

• Background

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• Physiology:

• Normal range and the significance of deviations (>5.5 mEq/L)

• Epidemiology:

• Prevalence of hyperkalemia in the ER • ESRD missed HD → ECG, monitor

Causes / Risk Factors

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• Causes

• Kidney Dysfunction, Medications, Cellular Destruction, Endocrine Causes, Pseudohyperkalemia

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• High-Risk Medications:

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• Antibiotics: Bactrim, antifungals

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• Calcineurin inhibitors

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• Beta-blockers

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• ACE/ARB

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• K+ Sparing diuretics

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• NSAIDs

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• Digoxin

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• SUX – high risks in neuromuscular disease

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• Lab errors, hemolysis in samples

• VBG vs Chem accuracy • When to repeat a hemolyzed sample • 2023 study: Of the 145 children with hemolyzed hyperkalemia, 142 (97.9%) had a normal repeat potassium level. Three children (2.1%) had true hyperkalemia: one had known chronic renal failure and was referred to the ED due to concern for electrolyte abnormalities; the other 2 patients had diabetic ketoacidosis (DKA).

Clinical Presentation / eval

• Symptomatic vs. Asymptomatic:

• “First symptom of hyperkalemia is death” • If severe, ascending muscle weakness → paralysis

• Point at which patients experience symptoms depends on chronicity

• >7 mEq/L if chronic and can be lower if acute

• Hyperkalemia can be a cause of non-specific GI symptoms

• EKG Changes:

• ECG findings may be the first marker the ER doc gets that something is wrong • Typical changes:

• Peaked T-waves, shortened QT • Lengthening of PR interval and QRS duration • Bradycardia / Junctional rhythm

• Hyperkalemia can produce bradycardia without other ECG findings

• Ones associated with VT/VF/code, death in one study: QRS widening (RR = 4.74), Junctional Rhythm (RR = 7.46), HR <50 (RR = 12.29) while no adverse outcomes with just peaked T waves or PR prolongation (Durfey, 2017)

• Don’t be fooled by a normal ECG, may be normal, but it’s also on case report level to have K > 9 and a normal ECG

• Series of 127 patient (K 6-9.3), no serious arrhythmia noted, only 46% had ECG changes, (Acker, 1998)

• ECG changes are not linear, there is no exact association between K+ levels and ECG changes • ECG changes may be hidden and subtle in patients with underlying inter-ventricular conduction delay (BBBs)

• Be suspicious of the patient with LBBB > 160 ms or RBBB > 140 ms

• BRASH Syndrome

• Synergism between hyperkalemia, renal failure/injury and AV nodal blocking agents -> may produce ECG changes out of proportion to serum potassium levels.

• Labs

• Chem, VBG, +/- CK if you think muscle breakdown is at play (Tintinalli talks about looking at urine K, but this is not most people’s practice) • Consider evaluation for adrenal insufficiency • Waiting for labs may not be an option

• Renal dysfunction + consistent ECG findings → prompt treatment before chem results • Realistically 2 hours to get back chemistry in most settings ≈ eternity

Management in the ER

• Discontinue/hold any nephrotoxins or medications in suspected medication-induced hyperkalemia

• A. Acute Management Strategies:

• Cardiac protection with calcium

• 1g over 5-10 mins

• Lasts 30-60 mins, may have to redose • Dose considerations if on digoxin • AEs: Calciphylaxis and hypercalcemia

• Fast pushes can result in hypotension, arrhythmia

• Calcium chloride vs calcium gluconate • Caution in patients taking Digoxin

• IVF choice – NS vs LR

• Caution/Avoid fluid in patients with ESRD/CHF or signs of VOL

• Shifting potassium:

• insulin/glucose

• 5 units vs 10 units

• 5 similar effect, less hypoglycemic episodes (LaRue 2017) • If doing 10 units, start D10W at 50-75 cc/h after amp of d50 but be mindful that anuric patient who missed HD may not have much room…

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