George Zhong

Propofol Dreams is a free app that empowers clinicians and assists with all aspects of TIVA workflow. It's now available as a web app!! app.propofoldreams.org Here are the key functionalities and how it can make your TIVA more precise, efficient and reduce waste... 1/8

❤️❤️ Our cardiology friends asked, so we answered!! PropoScroll now has the latest cardiology literature too! Give it a scroll to keep updated with the latest studies today! proposcroll.propofoldreams.org

What PropoScroll does: - abstracts from top anaesthesia journals summarized - key take home messages in a scrollable format - link to full abstracts on Pubmed Features to come: - filter by topic - learns your interests and individualized - comment system - your request!!

Do you want to keep up with anaesthesia literature but find it "too hard"? Do you find doomscrolling "too easy"? What happens when the two meet? Introducing my new pet project ** PropoScroll ** proposcroll.propofoldreams.org Why not give it a scroll while waiting for the surgeon...

@maffygirl @NicholasChrimes @noolslucas And ANZCA PG18 ... Open to interpretation ... Our amazing anaesthetic nurses usually put dots on back and side to facilitate skin to skin 🤜🏼🤛🏻

Agree with absolutely everything @noolslucas said about #ObstetricAnaesthesia on #BILIH (& there's not many people I can say that about!). Standard Epidural 1st line for obstetric analgesia CSE judiciously DPE 🙄 Give a decent dose of IT LA (2.7ml heavy from me) IT morphine ✅ Vasopressor infusion ✅ A few extras from me: 27G spinal needle SpO2 probe on the toe for LSCS (so the mother can hold the baby) And (possibly controversially) no ECG for standard LSCS (not mandatory monitoring in Aust, gets in the way of mum & bub, gives me absolutely no useful information.

@NicholasChrimes Amount of CO2 presented to soda lime probably same if there's no scavenging/FGF/exit and it's a true closed circuit Again, you might be right, but it's hard to know without performing some calculations/simulations. @grok Just my gut feeling circuit matters ...

@NicholasChrimes Thought experiment of extreme cases: Zero circuit volume, all expired CO2 instantly meets canister, no buffer, huge peak flux Infinite circuit volume, all exhaled CO2 buffered by circuit, canister not needed Real life, depends on factors I previously mentioned. It's complex

Given paediatric circle circuits are lighter, take less time to wash in changes to gas concentrations & (maybe) have marginally less dead space at the Y-piece, can someone explain to me why we ever use adult circle circuits?

@NicholasChrimes Of course, the balance is complex Multiple factors govern the balance: CO2 production, MV, I:E ratio, FGF, exact circuit volume, channeling of CO2 through canister/soda lime design etc Net effect is economic/environmental of paed circuit gains vs canister replacement cost

@NicholasChrimes Adult w high MV (esp. laparoscopy) + smaller circuit volume = greater peak flux of CO2 through canister. If canister cannot efficiently absorb peak flux = FiCO2 elevation FiCO2 elevation interpreted as exhaustion = early replacement Sorry I can't answer Q2 for you.

@DocMattHart @MichiIntrona Lemme know if you want to extend ethics to next door and I can help you recruit at the adult hospital 😜 we share the same ethics committee anyway

@propofoldream @MichiIntrona We have one going through ethics at the moment. Main limitation for generalisability will be it's only designed to investigate this in adolescents, so a similar one in adult land would be most helpful...

We are, of course, fully aware that this is a technical paper, and that clinical data will eventually be needed(like LOC, BIS, so on). However, we deliberately chose TTPE and Ce/Cp as endpoints because they allow a fair, model-based comparison between the two techniques. In parallel, we are already working on additional analyses that are more explicitly clinical, which will be presented separately. The infusion rate is certainly open to discussion. To be honest, a 3-second bolus appears quite extreme, and the literature provides no clear guidance on what should be considered an appropriate or realistic administration speed. Our intent was simply to explore a range of conditions, including such an upper-limit scenario. What our results clearly show is that the difference in the rise of Ce between the two techniques is far smaller than one might intuitively expect. This, in itself, is an important point that addresses a common misconception. What is certain, however, is that boluses delivered at such high speeds mainly serve to rapidly saturate the central compartment, producing a marked haemodynamic impact, with all the associated consequences. @propofoldream @DocMattHart

@MichiIntrona Until we have that evidence, it's like medicolegal prisoner's dilemma ... 2 x 2 payoff matrix Pump bolus fast enough vs not Vs Bolus by pump vs manual Given, RSI is primarily intended to address increased aspiration risk, the equilibrium solution based on current evidence is ..

@MichiIntrona So we desperately need a clinical study designed to find: (1) Time to LOC (2) Time to onset of NMB (3) Range/variance of (1) and (2) For pump vs manual bolus For a clinically useful range of pts

@NicholasChrimes @easypocus @TheSnoozeDoctor Agree w you. Currently, there are already full self driving cars (with a failure rate), yet most people still choose to learn how to drive. Follow up question, if we plot failure rate on the X-axis and %learn to drive on the Y-axis, what will that curve look like?

@propofoldream @easypocus @TheSnoozeDoctor I think the answer to horses, manual transmission and non-self driving cars is 'No' across the board.

I can see a time coming when trainees become as deskilled in direct laryngoscopy as they already are with basic face mask technique. I make a point of ensuring they can manage a face mask properly for a straightforward 20 minute case.

@easypocus @NicholasChrimes @TheSnoozeDoctor I think the horses example is a bit extreme Rather along the same line, if we readily have access to automatic cars, should we still learn to drive manual? And in the same line of argument, in the future when we have self driving cars, should we still learn to even drive?

@NicholasChrimes @TheSnoozeDoctor great analogy! I tend to ask ppl if they keep horses for their non-resident on calls - in case their car breaks down…

@NicholasChrimes Agree, that's the scientific method. You can have the best model, the best simulation methodology, but it just takes one real life counterexample to disprove it Pragmatism

A few things: Manual bolus is over 15secs. I reckon I’d typically deliver the initial bolus over ~3 secs. Time to peak effect is not what’s relevant, it’s time to sleep. Clinically this is not the case. TCI inductions (even for non-RSI) are much slower (too slow) inductions.

@TheSnoozeDoctor @maffygirl Truth is environmental science is so insanely complex and there's so much we don't know ... Comparing carbon footprint and ecological impact is like apples vs oranges The only certainty is REDUCING waste. If we use less and achieve same pt outcome, then it MUST be greener.

@propofoldream @maffygirl TIVA is greener in the air, dirtier in the bin!

@maffygirl doi.org/10.1016/j.bja.… TIVA vs sevo Real cases, real workflow, real data At end of day, both sevo/TIVA are good anaesthesia techniques. Much can still be achieved by reducing wastage for each (e.g. low flow sevo, prudent drawing up of propofol, etc) #ThereIsNoPlanetB

@maffygirl The problem with these modelling studies is always the "model"/"assumptions", which often deviate very far from real world. E.g. the mandatory use of remifentanil, "quad" fusor, pEEG only for TIVA, no use of TCI, etc etc A better (real world) study is by Bernat BJA 2025.

@simtiva_app 🙏🏼🙏🏼 Thank you kindly Terence!!

@propofoldream @SGSocAnaes Amazing work George!

Thank you @SGSocAnaes for inviting us to present our work at #SARC2025, Singapore's first carbon neutral medical conference. Thank you Singaporean colleagues for dreaming big with us! 🙏🏼 🙏🏼 #ThereIsNoPlanetB 🫰🏼🫰🏼