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The 1970s were a dark time for ketamine use in patients with intracranial pathology. In patients with non-traumatic lesions, ketamine was suggested to increase intracranial pressure (ICP) using various markers as end-points to suggest this (see references below). Although this concern still remains with traditionalists, we have since seen multiple studies debunking this myth.
Now there is finally a meta-analysis supporting the suggestion that ketamine certainly does not seem to increase ICP. A systematic review of RCTs comparing the effects of ketamine vs opioids on 24-hour ICPs found that ketamine produced similar changes to ICP, MAP and CPP when compared to opioids. Surprised? Me neither.
Although this paper has some obvious flaws (small numbers, only 5 trials included, different choice of opioids, trials took place over 17 years, boluses vs infusions not addressed), this is one of the first meta-analysis to look at this surprisingly commonly misunderstood practice.
It is probably time for those Anaesthetics/Emergency Medicine/Pharmacology text books to be rewritten. And it is probably time to stop discussing whether ketamine can be used as an induction agent in TBI.
Here is the programme for next week’s CGD.
We have a toxicology theme this week, so brush up on your tox knowledge with these poisonous resources:
The Toxicology Conundrum Series from LITFL
- Massive Propranolol Overdose
- Agitated Delirium
- Verapamil Overdose
- Corrosive Ingestion
- Overview of Snakebite Management
A Couple of Interesting Recent Toxinology Abstracts
Ultrasound Workshop – The FALLS Protocol
Massive thanks to our guest speaker Dr Chris Partyka from The Blunt Dissection for delivering an excellent workshop on critical care ultrasound! The content from his workshop, including the FALLS protocol for undifferentiated shock, is available here.
Advanced ECG Workshop – Chest Pain
Below are the images from the ECG workshop on chest pain, along with some learning points discussed on the day. Follow the links for more information on each individual topic.
- Peaked T waves + upsloping ST depression in the precordial leads = the De Winter ECG pattern. This is a sign of acute LAD occlusion and should be treated as a STEMI equivalent.
- Also note the ectopic atrial rhythm — P wave inversion in II, III + aVF.
Read more about De Winter’s T waves here.
ECG 2 Inferior STEMI with reciprocal change. There are additional signs of right ventricular infarction:
- STE in III > II
- STE in V1-2
This rightward vector of the injury current (III > II) suggests an RCA occlusion rather than a LCx occlusion. Repeat ECG with a V4R lead position confirms a right ventricular infarction (STE in V4R). Read more about right ventricular infarction here.
- Widespread horizontal ST depression, most prominent in the leftward-facing leads I, II and V4-6
- STE in aVR > 1mm
- STE in aVR > V1
ECG 4 This ECG is a classic example of acute pericarditis. Positive findings include:
- Widespread concave (“saddleback”) ST elevation
- Widespread PR segment depression
- Spodick’s sign – a down-sloping TP segment that gives the baseline a kind of “zig-zag” appearance
- ST segment / T wave height ratio > 0.25 in V6, which favours a diagnosis of pericarditis over benign early repolarization.
- ST elevation in II, III, aVF (inferior) plus leads I, V5-6 (lateral)
- ST depression in V1-3 with evolving dominant R waves (Q wave equivalent) and terminal T wave positivity = signs of posterior infarction
The leftward-facing injury vector suggests LCx rather than RCA occlusion, as recognised by:
- STE in II > III
- STE in I, V5-6
Repeat ECG with posterior leads (V7-9) confirms posterior wall infarction. Read more about posterior infarction here.
- Biphasic T waves in V1-3 (inverted in V4) typical of Wellens’ syndrome
- This ECG pattern is highly specific for a critical occlusion of the LAD.
Read more about Wellens’ syndrome here.
ECG 7 This ECG demonstrates LBBB with positive Sgarbossa criteria, indicating superimposed myocardial infarction:
- Concordant ST elevation in aVL
- Concordant ST depression / T wave inversion in II, III, aVF
- Additional concordant ST depression in V5
The pattern is suggestive of anterolateral STEMI with inferior reciprocal change. Sgarbossa criteria for diagnosing MI in the presence of LBBB or paced rhythm include:
- Concordant ST elevation > 1mm in any lead
- Concordant ST depression > 1mm in V1-3
- Excessively discordant ST elevation = ST elevation > 5mm (original Sgarbossa rule) or > 25% of S wave height (modified Smith rule)
Read more about the Sgarbossa criteria here.
ECG 8 This is an ECG of pulmonary embolism with right heart strain, demonstrating:
- Sinus tachycardia (present in ~50% of patients with PE)
- The right ventricular strain pattern = Simultaneous T-wave inversions in the right precordial (V1-3) and inferior leads (III, aVF)
- Minor, non-specific ST changes in multiple leads
Other ECG changes seen with PE include:
- Right axis deviation
- Complete or incomplete RBBB
- Dominant R wave in V1
- S1 Q3 T3 = neither sensitive nor specific for PE; found in only ~20% of patients
Read more about ECG changes in PE here.
ECG 9 This is an example of benign early repolarization, demonstrating:
- Concave (“saddleback”) ST elevation in multiple leads, most prominent in the precordial leads.
- J-point notching (the “fish-hook pattern”) in V4.
- ST segment / T wave height ratio < 0.25 in V6, which favours BER over pericarditis.
- No features of acute STEMI — the T-wave inversion in III is a normal variant.
Read more about benign early repolarization here.
- Updates in Ultrasound – A hands-on refresher session on eFAST, RUSH and basic echo with special guest Dr Chris Partyka (Ultrasound Registrar at Liverpool Hospital, EM blogger at The Blunt Dissection).
- ECGs to Rock a Retrievalist – Advanced ECG Workshop by Dr Ed Burns (author of the Life in the Fast Lane ECG Library).
Pre-Reading Brush up on your ultrasound and ECG knowledge with these useful FOAM resources.
- Mount Sinai Emergency Medicine Ultrasound series — Tutorials on FAST and RUSH
- Academic Life in Emergency Medicine — Excellent overview of the RUSH protocol
- Cliff’s awesome talk on Trauma USS as presented on the Ultrasound Podcast (you might recognise this one from our HEMS induction week)
- Scott Weingart’s 2-part lecture on RUSH — Part 1 (busy readers skip to ~11:40 to get to the main points) and Part 2
Some other US websites worth checking out:
Electrocardiography Resources The theme of the ECG workshop is chest pain. Check out the following pages from the LITFL ECG Library:
Some other ECG websites worth checking out:
Looking forward to seeing you there!
All NSW Health staff welcome. Sign in required. See here for directions.
The latest CGD saw us look at all things airway. With some scary case-based discussions, excellent debate, a great presentation on the NAP4 findings and a simulation that would make the most senior anaesthetist experience code brown moments, the Sydney HEMS team came away from the education day more prepared and equipped to handle airway difficulties.