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 <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

Elevator Speeches

The Look & Sound of Leadership

Introduction

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