Dr. Emery Neal Brown, 54, is a professor of anesthesiology at
Harvard Medical School,
a professor of computational neuroscience at M.I.T. and a practicing physician, seeing patients at
. Between all that, he heads a laboratory seeking to unravel one of medicine’s big questions: how anesthesia works. Massachusetts General Hospital
Q. Anesthesia — what drew you to it?
I enjoyed my anesthesia rotation at medical school. I could see that it was very fast-paced and that you had to make important decisions quickly. That appealed.
It’s also a very important piece of modern medicine. If you think about what occurs
when we do surgery, it’s a very traumatic insult to the body. You’re cutting people open, removing organs or possibly even transplanting them. The anesthesiologist puts people into a condition where they can tolerate such extreme assaults.
Q. Is anesthesia like a coma?
It’s a reversible drug-induced coma, to simplify. As with a coma that’s the result
of a brain injury, the patient is unconscious, insensitive to pain, cannot move or remember. However, with anesthesia, once the drugs wear off, the coma wears off.
Q. Is it true that we don’t really know how anesthesia works?
It’s viewed as a mystery and that’s wrong. It’s not a black box. There’s a lot that is actually known, and more is developing as neuroscience moves forward. We’ve certainly known how to make anesthesia safe. We watch the patient while he or she is “under.” We know what’s normal in terms of heart rate, blood pressure, temperature, gases, etc.
If things start to deviate from that, we intervene. We’ve gotten very far by creating high standards for care while under anesthesia.
Q. In your research, you’ve been trying to figure out how anesthesia actually works. How do you go about doing that?
Since 2004 we have been doing experiments to understand how the brain works under anesthesia. We’ve been taking volunteers and giving them anesthesia, though not in the midst of actual surgeries.
As our subjects go under, we image their brains in functional M.R.I. scanners and measure brain activities with EEG monitors. Before this technology was available, researchers had only looked at what happened to patients before and after anesthesia. But with today’s functional M.R.I., we can watch people lose consciousness — see how the various parts of the brain change in activity. We can watch the transitions, what parts of the brain are turned on and off.
Q. Were there ethical problems in designing a study where you rendered your subjects unconscious?
Absolutely. Because some people felt, “This is anesthesia! You should only administer it when people need surgery.” Our study got more scrutiny than any other at this hospital.
The way we overcame potential objections was by recruiting a unique set of study subjects. They were patients who’d already had tracheostomies — surgical holes in their throat. We could place a tube into the hole and connect it to a breathing circuit. If anyone got into trouble while in the scanner, we’d immediately be able to help them breathe.
Q. What has your research shown so far?
We've found many aspects of an EEG of anesthesia are really consistent with patients who are in a coma. The key difference is that anesthesia is reversible.
Q. Years ago when I had an operation, I remember the anesthesiologist trying to soothe me, by saying that she was going to put me “to sleep” Was this right?
No. And I wish we’d refrain from saying that to patients. It’s inaccurate. It would be better if we explained exactly what the state of general anesthesia is and why it’s needed. Patients appreciate this intellectual honesty. Moreover, anesthesiologists should never say “put you to sleep” because it is exactly the expression used when speaking about euthanizing an animal!
Q. You say a brain under general anesthesia more closely resembles a brain in coma than asleep. Is the distinction clear?
Your brain is in a completely different state in sleep compared with being in a coma or general anesthesia and the differences are not subtle. It is apples and oranges.
Think about it. If you are deeply asleep, I can eventually shake you awake. In a state of general anesthesia that won't happen.
Surgery is invasive and traumatic and you need to be in a state that is like a coma to tolerate it. General anesthesia goes beyond simply controlling pain. It has four components. You are supposed to be unconscious. You are not supposed to remember – having open heart surgery is not an experience you want to remember. Third you must not feel pain and fourth you should not be about to move about.
Q. And yet we still talk about putting people to sleep…
If you came in for an operation and I told you I was going to put you into a coma, you would probably get up and run away! The idea of being put to sleep is a euphemism. But I think it is important to be honest. We need to educate the public more. For your surgery you need to be in a state of general anesthesia, not sleep, for the reasons above – I can put you in, I can bring you out.
Q. What is the potential of your research?
The possibilities are limitless. Insomnia is a big problem, for example. A lot of insomnia drugs work like low doses of anaesthetic drugs – they create sedation, not sleep.
The goal of treating insomnia is to promote natural sleep, but sleep is a cycle as your brain moves between REM and non-REM sleep. That is why people who take a sedative may wake up and still feel groggy. They haven't been through the natural stages of sleep necessary for the body to recover. If we work from what we now know – that anesthesia isn't sleep– then we can help.
Q. Why would someone like Michael Jackson take Propofol for insomnia?
I can only conjecture. But that incident is another reason why I think we need to be more precise describing what we do. If an anesthesiologist says, “We’re going to have you go to sleep” some might think you could use these drugs for sleep.
The bottom line is that when you’re under anesthesia, you’re in coma.