[HSF] Deairing the heart

Thu Mar 8 01:51:13 EST 2007

Al Starr's first patient died of air embolism a couple of weeks before the first meeting on artificial heart valves in Chicago in Sep 1955. 
Roberto and James I have not yet found the reference to the experiments in which  air was injected up dog carotids. I looked for our papers on echo in the OR (we had Mmode echo built into our two Electronics for Medicine monitoring machines in our OR's at Einstein in the mid seventies; maybe the world's first dedicated echo in a cardiac operating room). I could only find copies of two and I cannot identify the reference in question. Note that our first transesophageal echo's were obtained by tying an Mmode echo transducer to an early fiberoptic esophagoscope (no perforations ever!) and published in 1979.
By the way Ani if you read the early papers you will find that there have always been many ways to approach the subject of evacuating the air. Most can be made to work quite well. Because there are many does not mean that the goal is invalid. I suspect that you are an impatient surgeon and frustrated by having to spend extra time when more bubbles show up on the echo after you have been through your routine air removing maneuvers. Almost certainly you have missed doing an essential part properly if this happens. The more experienced you are at these tricks the more often nothing is seen at their completion. 
Don't respond or I will regard you as wilfully obtuse. 
Which statement of mine does NOT mean that I do not fully acknowledge that we do not know what number of snow flakes bopping around in the ventricle or aorta at the end of a case will damage the brain. It is because they may that we persist. 
It is interesting that much of the early work on clearing intracavitary air was concerned with avoiding damage to the myocardium; we could see the heart, see the bubbles in surface blood vessels and see the deterioration in the myocardial squeeze. Our patients, because of many imperfections with our perfusion and anesthesia systems, were quite often a bit fuzzy for a day or two, so we had nothing to observe let alone measure. However we had done work on being sure that we had a filter on the arterial side of the bypass machine that would trap air. Classic studies from Stanford showed that air down the venous line would show up in  the carotid arteries (detected by an early ultrasonic probe) very quickly in the absence of a filter. 
The late very great anatomy teacher, Stansfield of the Royal College of Surgeons, used ask to ask us "Gentlemen, what is the key to learning?" We knew well enough to answer in chorus "Eternal Repetition!"
Bob

-----Original Message-----
From: battr at medizin.uni-leipzig.de
To: OpenHeart-L at lists.hsforum.com
Sent: Wed, 7 Mar 2007 3:41 PM
Subject: AW: [HSF] Deairing the heart

Prasanna,
Do you know how did the first Starr valve patient die?
Ask Bob!
Roberto

-----Ursprüngliche Nachricht-----
Von: openheart-l-bounces at lists.hsforum.com
[mailto:openheart-l-bounces at lists.hsforum.com] Im Auftrag von prasannasimha
Gesendet: Mittwoch, 7. März 2007 15:09
An: OpenHeart-L at lists.hsforum.com
Betreff: Re: [HSF] Deairing the heart

Having gone through various phases of teaching =- from being taught to 
being a teacher let me tell you one thing - when making residents do an 
ASD the one thing that I personally will do is deair even if everything 
else is done by the resident.
I have seen enough residents having significant air embolisms during 
their learning curve that I insist on deairing once after they have done so.
In fact GB Parulkar (our senior teacher in KEM) would come to just deair !!
Being cavalier about deairing can and will cause problems. Most learn 
through the lessons learnt from their teachers but remember many have 
learnt this after paying a biter price.
The original problems in CPB were often related directly to air 
embolism. See the articles by Gibbon, Clarence Dennis etc who realized 
that this was one of the most important steps (which now is considered 
routine). In fact  Melrose developed "cardioplegia" not for myocardial 
protection but to develop a method to prevent "air embolism"
Prasanna
Ani Anyanwu wrote:
> The numerous and highly variable views on this topic, to the extent of
even discussing how to put a needle in the aorta to extract air best (I must
confess I was stunned at the seriousness many attach to this), consolidate
my view that most of what we do in this regard (deairing) is either,
ill-understood, inconsequential or irrelevant. 
>
> My suspicion is that it doesn’t really matter what we do - so far as one
gets the gross air out, the rest is fine talk. I know I will as usually
incur the wrath of my seniors, but if it is so crucial and as technical as
list members portray, how come we are getting so many highly opinionated but
varying views? Surely they can't all be right at the same time? Maybe they
can all be wrong though...Of course the red flag is that practically no
contributor on this has provided evidence (experimental or clinical) to
justify their deairing strategy - at the end of the day it is just surgeon
preference, voodoo or a recipe handed by our teachers. I suspect whatever
one chooses (apart from ignoring the air) works, not because of what we do,
but because of the attempts we make (by whatever means) to remove the air.
>
> Ani
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