When you are in the operating room, counting backwards, about to disappear into sweet oblivion, your anesthesiologist will know exactly what kind of dose you need, and how to monitor your heart rate and breathing, but anesthesiologists have a bit of a secret.

"Surprisingly, even though we use these drugs in easily 250 million patients every year across the world, and have been using them since about 1850, we don't know how they work," said Roderic Eckenhoff, a professor of anesthesiology at the University of Pennsylvania.

Anesthesia was developed basically by observation — noticing what works, and getting the hang of it. However the process, what exactly it is that puts you to sleep and makes you feel no pain, is not fully understood.

Eckenhoff and a multi-disciplinary team of researchers in the fields of medicine, chemistry, and biology have just received an $8.6 million federal grant to further their understanding of the mechanics of anesthesia. Eckenhoff says the hope is that it could lead to reduced side-effects from going under.

"There is concern right now, for example, that these drugs could have a durable cognitive effect, in other words, they might not leave the brain entirely unchanged," he explained.

A better understanding of the process of anesthesia could also lead to new drugs. Eckenhoff hopes for ones that don't have such a big impact on patients' heart rate and breathing.

"For example, when we have a trauma patient, who needs anesthesia for an operation, we have to tread very lightly in those patients because of the significant cardiovascular and respiratory effects of our drugs, they can tip somebody over the edge who is already very close to the edge," said Eckenhoff.