For cardiac surgery, your brain on ice

We need blood to live, but blood makes life difficult for heart surgeons by obscuring the operating field. At a certain point in surgery on the aorta, the body’s largest artery, surgeons must shut down the cardiopulmonary bypass machine, stopping blood flow entirely and cutting the oxygen supply to the fuel-hungry brain.

To prevent brain damage, the patient’s head is carefully packed in ice and the body cooled until its core temperature reaches about 19°C (66°F), which slows metabolism to a standstill. For added brain protection, some surgeons use perfusion, pumping blood into the cerebral arteries, but this clutters the workspace and creates possible complications.

In the September issue of Annals of Thoracic Surgery, a Yale team led by John A. Elefteriades, M.D., chief and William W.L. Glenn Professor of Cardiothoracic Surgery, shows that perfusion is unnecessary. The researchers studied the outcomes of 394 aortic arch operations performed at Yale without perfusion and found a stroke rate of only 4.8 percent, on par with the best results seen with perfusion.

But speed is key. Strokes occur more often during aortic operations lasting over 40 minutes, and the average patient at Yale spent only 31 minutes in suspended animation.