Episode 189: Hyperkalemia 2.0

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 Download 2 Comments Tags: Renal Colic Show Notes Introduction Background 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 Causes Kidney Dysfunction, Medications, Cellular Destruction, Endocrine Causes, Pseudohyperkalemia High-Risk Medications: Antibiotics: Bactrim, antifungals Calcineurin inhibitors Beta-blockers ACE/ARB K+ Sparing diuretics NSAIDs Digoxin SUX – high risks in neuromuscular disease 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 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 for volume Decrease but about 0.5-1.2 mEq/L Effect starts 10-20 mins after administration and can last 4-6 hours Albuterol 10-20 mg over 10 mins (NB: higher dose than for asthma) Peak effect at 90 mins Decreases by 0.5 – 1.0 mEq/L alone With insulin, ~1.2 mEq/L, additive effect Bicarbonate Controversy. Useless in hyperkalemic, no

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