REBEL Cast REBEL Core Cast 109.0 – Na Channel Blocker Poisoning
9 snips
Sep 27, 2023 This podcast discusses the significance of ECG in evaluating overdose patients and the connection between QRS prolongation and sodium channel blockade. It explores ECG changes seen in tricyclic antidepressant and Diphenhydramine overdoses. The importance of considering sodium channel blockade as a differential diagnosis for widened QRS intervals is highlighted. Treatment recommendations for wide, complex tachycardia caused by sodium channel blockade with sodium bicarbonate are provided.
AI Snips
Chapters
Transcript
Episode notes
Wide QRS in Poisoning
- A QRS duration greater than 100 milliseconds in poisoning strongly suggests sodium channel blockade, not ventricular tachycardia.
- Right bundle is more vulnerable, causing right axis deviation and terminal R wave in aVR on ECG.
Lower QRS Threshold in Toxicology
- In poisoning contexts, a wide QRS cutoff is 100 ms, lower than cardiology's 120 ms threshold.
- Broader QRS correlates with increased risk of seizures and ventricular dysrhythmias.
Sodium Bicarbonate Dosage
- Administer 1-2 mEq/kg bolus of sodium bicarbonate for sodium channel blockade poisoning and start infusion if QRS narrows.
- Continue to give bicarbonate until QRS narrows and patient stabilizes, as high doses may be needed.
Take Home Points: In the context of poisoning, a “wide QRS” is anything greater than 100 milliseconds. A newly “wide QRS”, especially with hemodynamic instability, should prompt consideration of sodium channel blockade and not ventricular tachycardia. Treatment is guided by administration of sodium-bicarbonate. Recall that the resultant alkalemia driven by sodium-bicarbonate will shift potassium intracellularly. ...