1 April 2020 - Toxicology
Program
Senior Registrars
1130 - 1500 - Onsite COVID airway drills followed by WebEx program below when available. Please meet Stu and Alex in tutorial room at 1130am.
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1000 - 1100 - Introduction to Toxicology - Jacqueline
1100 - 1120 - TCA overdose - Tom Cooney
1130 - 1200 - CCB/BB overdose - Luke Bayley
Break
1215 - 1230 - COVID pathophysiology - Max Grant
1230 - 1300 - Imaging in COVID, CXR/ultrasound/CT - Mark Rugless
1300 - 1310 - ECG of the week - Alex
1310 - 1330 - Any other issues in COVID/Departmental updateNo
ECG of the Week
80 yo female presents with central chest pain. BP 80/40
This ECG shows an inferior STEMI with right ventricular infarction.
RV infarction is present in up to 40% of inferior STEMIs. It is important that in any patient with an inferior STEMI we look for RV infarction as it may change our initial management. These patients are pre-load sensitive (due to poor RV contractility) therefore avoid GTN and ensure the patient has adequate fluids.
Signs of RV infarction on ECG include:
ST Elevation in V1
ST Elevation in lead III > lead II
ST Elevation in V1 > V2
ST Elevation in V1 + ST depression in V2 (highly specific)
Right sided leads can confirm the diagnosis if in doubt.
Key learning Points from this week’s teaching
Toxicology
In the COVID era, there are potentially new exposures to bleach and hydrochloroquine
A general approach to the toxicology patient can be summarised with the acronym RRSIDEAD
Resucitation, Risk Assessment, Supportive Care, Investigations, Decontamination, Enhanced elimination, Antidotes, Disposition
Look for specific toxidromes - anticholinergic, cholineric, hallucinogen, opioid, seretonin syndrome, sympathomimetic etc
Remember to perform a toxicology risk assessment - knowledge of the drug , dose, formulation, time of ingestion, patient comorbidities and clinical features
Useful resources: Poisons Information Line 131126, Tox handbook, Austin Toxicology guidelines/mobile app
TCA Overdose
ECG Features: Tachycardia, prolonged QRS ( >100ms predictive of seizures, >160ms predictive of ventricular arrhythmia), tall R-wave in aVR
Antidote = sodium bicarbonate
Beta Blocker Overdose
Propranol has sodium channel blocker effects (manage as per TCA)
Sotalol has QT prolonging effects
Treatment may include fluids, atropine, isoprenaline, HIET
Calcium Channel Blocker Overdose
Non-Dihydropyridine CCB overdose (verapamil/diltiazem) are more severe
Treatment may include fluids, calcium, HIET, catecholamines
Imaging in COVID Patients
St Vincent Guidelines are available
CXR and CT are not recommended to diagnose COVID-19
CXR can be used to exclude alternative diagnoses of respiratory failure and when the patient has features of a LRTI
CT should only be used if a complication is suspected such as empyema
POCUS may reveal subpleural consolidation and increased B lines which are bibasal and posterior