Dr Matt Hart

Paediatric Anaesthetist. Regionalist and TIVA diva.

[Dr Matt Hart @DocMattHart]

@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...

[Dr Matt Hart @DocMattHart]

@MichiIntrona (Apologies for the broken reply, the character limitation is at times frustrating!)

[Dr Matt Hart @DocMattHart]

@MichiIntrona Meaning the difference in TTPE of 20-30 for 2-2.5mg/kg boluses might be seen as unacceptable locally.

Were a patient to aspirate prior to intubation, you would likely be criticised by a large number of colleagues and medicolegal system here if you used a "slower" technique.

[Dr Matt Hart @DocMattHart]

@MichiIntrona In e.g. AUS/NZ/UK there is emphasis on rapid administration of induction agents. 3s might seem "extreme" from your perspective, but wouldn't be called that here. A quick straw poll of my department here suggests 15s is "slow"! Highlighting again cultural variation.

[Dr Matt Hart @DocMattHart]

@MichiIntrona I actually think it's a good study. I think what is highlighted in this discussion though is how the lack of evidence for individual components of the RSI leads to a large variation in acceptable practice in different societal / geographic contexts. This affects practice.

[Dr Matt Hart @DocMattHart]

@NicholasChrimes https://t.co/yGajga65tR The anecdotal speed difference is why we worked with our local pump manufacturer to add an RSI mode to our pumps, which allows clinicians to give a manual bolus, and the pump will then account for that in its PK modelling. Best of both worlds.

[Dr Matt Hart @DocMattHart]

@NicholasChrimes Using time to peak effect (~200s) also makes the relative difference percentage they quote smaller. They say a 2.5mg/kg bolus is only 14% slower, based on 229s TTPE vs 200s TTPE for a bolus. 29s difference in time to LOC may be more problematic.

[Dr Matt Hart @DocMattHart]

@NicholasChrimes @Anaes_Journal The Orihara study retrospectively analysed 5 years worth of anaesthetic records, so underestimating less likely. Other factors may be at play though, e.g. environmental exposure or sensitisation from high use. Either way I use it like roc: only if I have a good reason 😂.

[Dr Matt Hart @DocMattHart]

@NicholasChrimes @Anaes_Journal I suppose it's one of the problems of trying to make inferences from rare outcomes. Pharmacovigilance data like that from France risks underestimating, but aligns with similar studies from Korea and UK.

[Dr Matt Hart @DocMattHart]

@sherlockedverne @Anaes_Journal We used @simtiva_app for our modelling. A really excellent tool!

[Dr Matt Hart @DocMattHart]

@mick_kerr @Anaes_Journal We were motivated to develop this precisely because as you say some people still think letting a pump deliver the initial bolus over a minute or more is fine.

[Dr Matt Hart @DocMattHart]

@mick_kerr @Anaes_Journal That's what this new mode does. You deliver the bolus by hand, and because you've told the pump what bolus amount was given it accounts for it in the TCI model. You get the "best of both worlds"; delivering a manual bolus but preserving the model.

[Dr Matt Hart @DocMattHart]

@Andyrooz22 @Anaes_Journal That's what this mode lets clinicians do. You deliver a manual bolus that you feel is appropriate for the patient, as a rapid manual push, and the pump accounts for this because you've told it what manual bolus you gave.

[Dr Matt Hart @DocMattHart]

@DrGeorgeHarvey @Anaes_Journal The orange line represents the simulation of what this new mode does (a clinician delivered bolus that the pump is aware of and incorporates in its modelling) vs what pumps do at present (20ml/min infusion speed).

[Dr Matt Hart @DocMattHart]

@foi_requests @Anaes_Journal The orange line represents the simulation of what this new mode does (a clinician delivered bolus that the pump is aware of and incorporates in its modelling) vs what pumps do at present (20ml/min infusion speed).

[Dr Matt Hart @DocMattHart]

@DrNickB_ObAnaes @Anaes_Journal It's available on all Arcomed pumps now I believe. Other manufacturers could likely also implement similar functions if they felt so inclined.

[Dr Matt Hart @DocMattHart]

@DrNickB_ObAnaes @Anaes_Journal The slight difference here is that the anaesthetist themself delivers the bolus manually (not limited by pump infusion rates), but the TCI pump is aware of this bolus and incorporates it into the PK-PD modelling.

[Dr Matt Hart @DocMattHart]

@johncampbell01 @Anaes_Journal The idea being "best of both worlds". Clinicians get to deliver their RSI bolus manually, but the TCI model remains "intact".

[Dr Matt Hart @DocMattHart]

@johncampbell01 @Anaes_Journal The blue line simulates what TCI pumps currently do (bolus delivered at 20ml/min), whereas the orange line simulates this new mode; a clinician delivered rapid manual bolus which the pump knows about and incorporates into its modelling.