Photo by akeg.

This week at the collaborative science blog Nothing in Biology Makes Sense, my brother Jon, a third-year med school student, describes his experiences helping out with open-heart surgery:

I stood on the other side, holding the still-beating heart out of the way. I couldn’t help but be amazed at the calm at which they did this, as if this were a perfectly normal and ordinary thing to do. Then, once all the lines were in place, a clamp was placed on the aorta, completely isolating the heart from the circulation of blood in the rest of the body. At this point, the heart is cooled down with ice and infused with a solution that arrests it in the phase of contraction called diastole. This is when the timer starts: From this point on the surgeon can operate for up several hours without any damage occurring to the heart.

For all the (not actually very gory) details, go read the whole thing. ◼