----- Original Message -----
From: Adrian Fogarty <[log in to unmask]>
To: <[log in to unmask]>
Sent: Sunday, September 16, 2001 10:58 PM
Subject: Re: a clearer posting on prilocaine
> .
>
> The pressure relates to filling the distal limb - below the wrist - with
> 40mls of fluid. It makes little difference if you inject slowly or
quickly,
> and it makes no difference at all which size of syringe you use, as you
> still end up with 40mls in the distal venous system. But I think you've
> missed my point Helen - the whole idea is to deliberately develop
sufficient
> distal venous pressure to force the fluid into the fracture site! I note
> Ray's post about the glasgow study, and unfortunately I can only quote
> anecdotal experience, i.e. antecubital injections produce very nice
> anaesthesia of the antecubital skin but poor anaesthesia of the wrist
> fracture. I too have no other evidence...
>
> Adrian Fogarty
>
> Adrian, I was interested in your idea that increasing the pressure will
force the anaesthetic into the fracture site. Is this how a Bier block works
? In that case why not just do a haematoma block ? Or is it that it
anaesthetises the nerves running along the neuro-vascular bundle, upstream
aswell as downstream, which is why a proximal cannula siting would
theoretically work as well as a distal ?. As to injection speed, I have
never found a problem with shooting the stuff in as fast as it will go,
which is usually pretty slow owing to the little bluey I've put in. I
suspect that we all have our own techniques and rituals because we don't
know exactly how it does work.
Paul Ransom
SpR Hastings
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