From: sbharris@ix.netcom.com(Steven B. Harris)
Newsgroups: sci.med
Subject: Re: i.v. injection question for m.d.
Date: 10 Aug 1998 04:34:36 GMT

In <35cdb79e.353002@news.datacomm.ch> cweil@gmx.net writes:

>On Fri, 07 Aug 1998 07:27:44 GMT, jl21@my-dejanews.com wrote:
>
>>How much air is dangerous to enter the bloodstream via i.v. injection ?
>>A nurse told me that anything less than 1mL(1cc) is harmless- is this
>>accurate ? Any helpful responses are appreciated.
>>
>>John Lewis
>>Montgomery, Alabama
>
>There is really no reason at all for a correctly performed intravenous
>injection to contain even a tiny air bubble.


   Nevertheless, a few cc's of air in your venous system (a standard IV
line) would be harmless, unless you were unlucky enough to have a
congenital atrial or ventricular septal defect, allowing bubbles to
bypass the lungs.  Lungs are a great filter, and they trap bubbles and
clots before they get to the brain or other places where they do damage
by interfering with blood supply.

   Failing a heart defect, the amount of air necessary to kill a normal
person varies a great deal depending on position, chance, rapidity of
injection, etc.  It's more than several hundred cc's.  Generally, you
need enough to create a giant bubble in the right heart, large enough
to interfere with liquid pumping ("vapor lock").

    A few patients have probably seen a little bubble go down their IV
line and into them, and had heart attacks waiting for the heart attack!

                                   Steve Harris, M.D.