You've probably heard that carbon dioxide is warming the Earth, but how does it work?
Is it like the glass of a greenhouse or like an insulating blanket?
Well, not entirely.
The answer involves a bit of quantum mechanics, but don't worry, we'll start with a rainbow.
If you look closely at sunlight separated through a prism, you'll see dark gaps where bands of color went missing.
Where did they go?
Before reaching our eyes, different gases absorbed those specific parts of the spectrum.
For example, oxygen gas snatched up some of the dark red light, and sodium grabbed two bands of yellow.
But why do these gases absorb specific colors of light?
This is where we enter the quantum realm.
Every atom and molecule has a set number of possible energy levels for its electrons.
To shift its electrons from the ground state to a higher level, a molecule needs to gain a certain amount of energy.
No more, no less.
It gets that energy from light, which comes in more energy levels than you could count.
Light consists of tiny particles called photons and the amount of energy in each photon corresponds to its color.
Red light has lower energy and longer wavelengths.
Purple light has higher energy and shorter wavelengths.
Sunlight offers all the photons of the rainbow, so a gas molecule can choose the photons that carry the exact amount of energy needed to shift the molecule to its next energy level.
When this match is made, the photon disappers as the molecule gains its energy, and we get a small gap in our rainbow.
If a photon carries too much or too little energy, the molecule has no choice but to let it fly past.
This is why glass is transparent.
The atoms in glass do not pair well with any of the energy levels in visible light, so the photons pass through.
So, which photons does carbon dioxide prefer?
Where is the black line in our rainbow that explains global warming?
Well, it's not there.
Carbon dioxide doesn't absorb light directly from the Sun.
It absorbs light from a totally different celestial body.
One that doesn't appear to be emitting light at all: Earth.
If you're wondering why our planet doesn't seem to be glowing, it's because the Earth doesn't emit visible light.
It emits infared light.
The light that our eyes can see, including all of the colors of the rainbow, is just a small part of the larger spectrum of electromagnetic radiation, which includes radio waves, microwaves, infrared, ultraviolet, x-rays, and gamma rays.
It may seem strange to think of these things as light, but there is no fundamental difference between visible light and other electromagnetic radiation.
It's the same energy, but at a higher or lower level.
In fact, it's a bit presumptuous to define the term visible light by our own limitations.
After all, infrared light is visible to snakes, and ultraviolet light is visible to birds.
If our eyes were adapted to see light of 1900 megahertz, then a mobile phone would be a flashlight, and a cell phone tower would look like a huge lantern.
Earth emits infrared radiation because every object with a temperature above absolute zero will emit light.
This is called thermal radiation.
The hotter an object gets, the higher frequency the light it emits.
When you heat a piece of iron, it will emit more and more frequencies of infrared light, and then, at a temperature of around 450 degrees Celsius, its light will reach the visible spectrum.
At first, it will look red hot.
And with even more heat, it will glow white with all of the frequencies of visible light.
This is how traditional light bulbs were designed to work and why they're so wasteful.
95% of the light they emit is invisible to our eyes.
It's wasted as heat.
Earth's infrared radiation would escape to space if there weren't greenhouse gas molecules in our atmophere.
Just as oxygen gas prefers the dark red photons, carbon dioxide and other greenhouse gases match with infrared photons.
They provide the right amount of energy to shift the gas molecules into their higher energy level.
Shortly after a carbon dioxide molecule absorbs an infrared photon, it will fall back to its previous energy level, and spit a photon back out in a random direction.
Some of that energy then returns to Earth's surface, causing warming.
The more carbon dioxide in the atmosphere, the more likely that infrared photons will land back on Earth and change our climate.
I'm going to talk to you today about the design of medical technology for low-resource settings.
I study health systems in these countries.
And one of the major gaps in care, almost across the board, is access to safe surgery.
Now one of the major bottlenecks that we've found that's sort of preventing both the access in the first place, and the safety of those surgeries that do happen, is anesthesia.
And actually, it's the model that we expect to work for delivering anesthesia in these environments.
Here, we have a scene that you would find in any operating room across the US, or any other developed country.
In the background there is a very sophisticated anesthesia machine.
And this machine is able to enable surgery and save lives because it was designed with this environment in mind.
In order to operate, this machine needs a number of things that this hospital has to offer.
It needs an extremely well-trained anesthesiologist with years of training with complex machines to help her monitor the flows of the gas and keep her patients safe and anesthetized throughout the surgery.
It's a delicate machine running on computer algorithms, and it needs special care, TLC, to keep it up and running, and it's going to break pretty easily.
And when it does, it needs a team of biomedical engineers who understand its complexities, can fix it, can source the parts and keep it saving lives.
It's a pretty expensive machine.
It needs a hospital whose budget can allow it to support one machine costing upwards of 50 or $100,000.
And perhaps most obviously, but also most importantly -- and the path to concepts that we've heard about kind of illustrates this -- it needs infrastructure that can supply an uninterrupted source of electricity, of compressed oxygen, and other medical supplies that are so critical to the functioning of this machine.
In other words, this machine requires a lot of stuff that this hospital cannot offer.
This is the electrical supply for a hospital in rural Malawi.
In this hospital, there is one person qualified to deliver anesthesia, and she's qualified because she has 12, maybe 18 months of training in anesthesia.
In the hospital and in the entire region there's not a single biomedical engineer.
So when this machine breaks, the machines that they have to work with break, they've got to try and figure it out, but most of the time, that's the end of the road.
Those machines go the proverbial junkyard.
And the price tag of the machine that I mentioned could represent maybe a quarter or a third of the annual operating budget for this hospital.
And finally, I think you can see that infrastructure is not very strong.
This hospital is connected to a very weak power grid, one that goes down frequently.
So it runs frequently, the entire hospital, just on a generator.
And you can imagine, the generator breaks down or runs out of fuel.
And the World Bank sees this and estimates that a hospital in this setting in a low-income country can expect up to 18 power outages per month.
Similarly, compressed oxygen and other medical supplies are really a luxury, and can often be out of stock for months or even a year.
So it seems crazy, but the model that we have right now is taking those machines that were designed for that first environment that I showed you and donating or selling them to hospitals in this environment.
It's not just inappropriate, it becomes really unsafe.
One of our partners at Johns Hopkins was observing surgeries in Sierra Leone about a year ago.
And the first surgery of the day happened to be an obstetrical case.
A woman came in, she needed an emergency C-section to save her life and the life of her baby.
And everything began pretty auspiciously.
The surgeon was on call and scrubbed in.
The nurse was there.
She was able to anesthetize her quickly, and it was important because of the emergency nature of the situation.
And everything began well until the power went out.
And now in the middle of this surgery, the surgeon is racing against the clock to finish his case, which he can do -- he's got a headlamp.
But the nurse is literally running around a darkened operating theater trying to find anything she can use to anesthetize her patient, to keep her patient asleep.
Because her machine doesn't work when there's no power.
This routine surgery that many of you have probably experienced, and others are probably the product of, has now become a tragedy.
And what's so frustrating is this is not a singular event; this happens across the developing world.
35 million surgeries are attempted every year without safe anesthesia.
My colleague, Dr. Paul Fenton, was living this reality.
He was the chief of anesthesiology in a hospital in Malawi, a teaching hospital.
He went to work every day in an operating theater like this one, trying to deliver anesthesia and teach others how to do so using that same equipment that became so unreliable, and frankly unsafe, in his hospital.
And after umpteen surgeries and, you can imagine, really unspeakable tragedy, he just said, "That's it.
I'm done.
That's enough.
There has to be something better."
He took a walk down the hall to where they threw all those machines that had just crapped out on them, I think that's the scientific term, and he started tinkering.
He took one part from here and another from there, and he tried to come up with a machine that would work in the reality that he was facing.
And what he came up with: was this guy.
The prototype for the Universal Anesthesia Machine -- a machine that would work and anesthetize his patients no matter the circumstances that his hospital had to offer.
Here it is, back at home at that same hospital, developed a little further, 12 years later, working on patients from pediatrics to geriatrics.
Let me show you a little bit about how this machine works.
Voila!
Here she is.
When you have electricity, everything in this machine begins in the base.
There's a built-in oxygen concentrator down there.
Now you've heard me mention oxygen a few times at this point.
Essentially, to deliver anesthesia, you want as pure oxygen as possible, because eventually you're going to dilute it, essentially, with the gas.
And the mixture that the patient inhales needs to be at least a certain percentage oxygen or else it can become dangerous.
But so in here when there's electricity, the oxygen concentrator takes in room air.
Now we know room air is gloriously free, it is abundant, and it's already 21 percent oxygen.
So all this concentrator does is take that room air in, filter it and send 95 percent pure oxygen up and across here, where it mixes with the anesthetic agent.
Now before that mixture hits the patient's lungs, it's going to pass by here -- you can't see it, but there's an oxygen sensor here -- that's going to read out on this screen the percentage of oxygen being delivered.
Now if you don't have power, or, God forbid, the power cuts out in the middle of a surgery, this machine transitions automatically, without even having to touch it, to drawing in room air from this inlet.
Everything else is the same.
The only difference is that now you're only working with 21 percent oxygen.
Now that used to be a dangerous guessing game, because you only knew if you gave too little oxygen once something bad happened.
But we've put a long-life battery backup on here.
This is the only part that's battery backed up.
But this gives control to the provider, whether there's power or not, because they can adjust the flows based on the percentage of oxygen they see that they're giving the patient.
In both cases, whether you have power or not, sometimes the patient needs help breathing.
It's just a reality of anesthesia, the lungs can be paralyzed.
And so we've just added this manual bellows.
We've seen surgeries for three or four hours to ventilate the patient on this.
So it's a straightforward machine.
I shudder to say simple; it's straightforward.
And it's by design.
You do not need to be a highly trained, specialized anesthesiologist to use this machine, which is good because, in these rural district hospitals, you're not going to get that level of training.
It's also designed for the environment that it will be used in.
This is an incredibly rugged machine.
It has to stand up to the heat and the wear and tear that happens in hospitals in these rural districts.
And so it's not going to break very easily, but if it does, virtually every piece in this machine can be swapped out and replaced with a hex wrench and a screwdriver.
And finally, it's affordable.
This machine comes in at an eighth of the cost of the conventional machine that I showed you earlier.
So in other words, what we have here is a machine that can enable surgery and save lives, because it was designed for its environment, just like the first machine I showed you.
But we're not content to stop there.
Is it working?
Is this the design that's going to work in place?
Well, we've seen good results so far.
This is in 13 hospitals in four countries, and since 2010, we've done well over 2,000 surgeries with no clinically adverse events.
So we're thrilled.
This really seems like a cost-effective, scalable solution to a problem that's really pervasive.
But we still want to be sure that this is the most effective and safe device that we can be putting into hospitals.
So to do that, we've launched a number of partnerships with NGOs and universities, to gather data on the user interface, on the types of surgeries it's appropriate for, and ways we can enhance the device itself.
One of those partnerships is with Johns Hopkins just here in Baltimore.
They have a really cool anesthesia simulation lab out in Baltimore.
So we're taking this machine and recreating some of the operating theater crises that this machine might face in one of the hospitals that it's intended for, and in a contained, safe environment, evaluating its effectiveness.
We're then able to compare the results from that study with real-world experience, because we're putting two of these in hospitals that Johns Hopkins works with in Sierra Leone, including the hospital where that emergency C-section happened.
So I've talked a lot about anesthesia, and I tend to do that.
I think it is incredibly fascinating and an important component of health.
And it really seems peripheral, we never think about it, until we don't have access to it, and then it becomes a gatekeeper.
Who gets surgery and who doesn't?
Who gets safe surgery and who doesn't?
But you know, it's just one of so many ways that design, appropriate design, can have an impact on health outcomes.
If more people in the health-delivery space really working on some of these challenges in low-income countries could start their design process, their solution search, from outside of that proverbial box and inside of the hospital -- In other words, if we could design for the environment that exists in so many parts of the world, rather than the one that we wished existed -- we might just save a lot of lives.
Thank you very much.
(Applause)