Emergency Medicine In Training Review

It's that time of year again. Time for the in-training exam. Here are my review notes for this year, updated as I compile them. Originally posted to Google Docs but there is a 500 KB limit on files. Re-posted to my drop. If you would like to contribute, comment.

Awake Cardiac Bypass Surgery

There is nothing quite like watching surgery, as viewers of Gray's Anatomy will agree.


However, when the surgery is on yourself, and you happen to be having open heart surgery and you happen to be awake the whole time, I am not sure I would agree. This study, from Italy, examines the outcome of patients who undergo open-heart surgery while on cardiac bypass, while awake. Awake bypass surgery has actually been around for several years, first performed in the UK in 2003, first performed in the world in 1998, and in the USA in 2000. To watch an operation, check it out here. It's not quite like this dramatization, in which a talk show participant takes out his own heart.

Can you warm up that ultrasound gel for me?

So, the eternal kvetching point for patients exposed to ultrasound in the Emergency Department is, oooooh, "that ultrasound gel is cold".

I wondered why it feels so cold when it is kept at room temperature? For that matter, why can you touch a blanket when it is at room temperature, and it does not feel cold, whereas a stethoscope, or a metal counter may feel cold.

What is it about the sensation of cold that makes some things which may be 78 degrees seem freezing when your body is at 98 degrees, yet when the temperature of the air is 78 degrees you do not feel cold?

And as another question, does this have any diagnostic significance? Does a patient's response to cold indicate anything clinically? There are conditions with weird temperature findings, so-called hot cold reversal or dysesthesia. For example, ciguatera is a condition in which involved seafood can contain ciguatoxin, which can cause strange neurologic findings, including hot cold reversal.

I went back into the advanced thermodynamics and sensory physiology of my youth and looked all this up...hmmm. Didn't find much.Probably something to do with the specific heat of a substance.

Apparently there is something which scientists are calling the menthol receptor. There is even a knockout mouse!

However, you can actually purchase ultrasound gel warmers. Now that is a posh ER that has those!