Cool, good afternoon. My name is Skylamak Donald and I am CAD and technical lead at the London
Ambulance Service. For the next 25 minutes or so, the D in CAD is computerated dispatch
rather than design because that's going to make the whole talk a lot less confusing. Essentially
all of the technology and systems in our control room are looked after operationally by
me and my team. And I'm about to tell you a little story about the worst day of your life.
You are in cardiac arrest. Your heart has stopped beating. You have stopped
breathing and medically speaking you have died, which is not a great start to your afternoon.
But worry not, somebody has called 999 which for the avoidance of doubt is the Brexit version
of 1-1-2. So that's already increased your chance of survival from 0 to somewhere slightly above
0. But you don't care about all of that. You want to become less dead. This is the story
about all of the technology, systems and geospatial data that is going to help the London Ambulance
Service save your life. Now I'm going to go back to the beginning. So you'll have to bear
with me a minute before I get to the actual geo stuff. I promise it's coming. You've
gone into cardiac arrest and someone has called 999. Someone has identified that you've
stopped breathing and medical help has been summoned. But the start of that 999 call was
interesting. Put it out of your mind for a moment. Think about if you were designing the
platonic ideal 999 call. The kind of call that's perfect for treating spherical patients
in a vacuum. How would you start a 999 call? What's the first bit of information you would
ask for? Would you get the address? Would you find out what's wrong with the patient?
So let's talk about this because as you know now you're wrong. As you heard, this is the
opening phrase for all 999 calls to English ambulance services. And to understand why, I'm
going to play the clip again, but I'm going to dim it a bit and I'm going to overlay all of
the stuff that's going on whilst the call is in progress. Don't worry about understanding
it yet. I'm going to go into it as the talk goes on. But let's have a look.
It took 11 seconds from the call being answered until an ambulance was dispatched 11 seconds.
It's pretty impressive to be fair not to do our own horn. But as for how and why that happens,
let's explain why. So obviously not every call is going to be someone who stopped breathing.
So in 2017, NHS England replaced the previous sort of mesh match of call priorities
with the ambulance response program, which is five key levels of emergency response.
Category one is calls from people with life-threatening injuries and illnesses where every second
counts. Category two is for other emergency calls such as heart attack, serious bleeding,
other emergencies that really need to get to hospital quickly, but don't need that time critical
by the second response, including emergency care or PR. Category three is for urgent calls,
things like broken legs and falls without serious injuries, where you need to get to hospital,
but they can wait if we have higher priority calls and not enough ambulances. Category four is
less urgent calls for conditions such as sorry to save us at lunchtime, but diarrhea and vomiting.
And that sort of infection, those kind of things where an ambulance will eventually be sent
if there's no alternative, but you might get some advice or referrals instead. Category five
kind of doesn't exist. These are calls that almost definitely won't get an ambulance without
having some sort of assessment first by a clinician. Each call has a response time set by NHS England
of how long it should take by rolling average for us to get there. Category one is any resource
needs to get on scene within seven minutes and try to assist patient the rest of the categories
except Category five, which as I said, we don't really go to. We need to send the full ambulance
response within these timeframes. Some other facts for you at the moment in England,
ambulances never wait on station for calls to come in. Almost every ambulance, almost everywhere
in the UK, is currently on a job for the 10 million ish people that are in London right now,
including the 8 million live there and the 2 million that can be used in for work or leisure.
There are about 400, 300 to 500 ambulances on duty. So, there are never enough available.
However, if an ambulance needs to be diverted to a higher priority call, we can do that.
In London, that happens all the time. But how do you get your priority? You heard the nature of
call questions or knock questions in our clip because what Frostam really needed is another acronym
that ends in O.C. So, let's talk about the pre-tree our civ. These are the questions we are
asking at the beginning of the 999 call to establish if there's something critical happening
that we need to get a response sent ASAP. You heard is the patient breathing and we then ask if
the patient is breathing whether they're awake. If they're not awake, we ask whether they're
breathing is noisy because noisy breathing has been shown to when your unconscious has been shown
to be an indicator of potential cardiac arrest. And then we ask, tell me exactly what's happened.
That then lets us establish basically what's going on with the call. Finally, all of this,
we will ask, well, not you, you're dead per unit. We will ask, what's the address of the emergency?
This isn't a list though as you'll remember from the clip we kind of jump depending on where
it's relevant if we identify a critical situation in the earlier questioning. So, why do we do it this
way? Why not get the address first? There are two reasons we do this. One, we already know where you are.
Ish? So, when your 999 call connects in the UK, it's answered by BT, the formerly nationalised
telecoms company. BT, British telecom then pass it through to the service you ask for,
and when it connects to us, they deliver us this information. This is how it looks on our map.
This is called ISEC, the enhanced information system for emergency calls. We love a snappy acronym
and the it represents your approximate location based on the cell tower through which you made
your call and the signal strength is used to calculate this sort of radius. About 20 seconds into the call,
your phone sends an SMS message, yes, really, in 2025, in Britain, an SMS message with more
accurate location information once it's kicked in your GPS. This is called advanced mobile location,
or a ML, and it reduces the size of the circle because we now have a more accurate idea of where your
phone actually is. I am pleased to inform you that now over a decade of ML was introduced in 2025,
we are finally doing this with HTTP and we get streaming updates if your device changes location,
or the GPS fix gets better and the circle gets smaller. The second reason we ask the questions
the other way up, which you've probably already worked out by now is we're looking for a category one.
These are the most time critical life-and-death kinds of calls, as I said, so the quicker we can identify
one, the quicker we can get help sent to you. If we identify one of those conditions in the pre-3RC,
we can send off what we call a predicted category one. At the point we heard into the presentation,
it's not breathing, it's not awake with noisy breathing or in certain other conditions. From the call,
you'll see the category one not predict identified stage here, 10 seconds into the call.
As I say, we have other reasons to send out calls, a category one calls based on the nature of what's
happened. If response to tell me exactly what's happened, they trigger another one of our knock
criteria. That might include someone actively having a seizure, drowning someone who's unconscious
following trauma, that kind of stabbing one of those kind of really serious incidents where
every second counts. So if we've already spotted a cat one and we already have kind of a good
enough location, why are we even bothering with the rest? Why are we actually asking for the address
of the emergency at the end of the pre-3RC? Let's have a look at the question. Have you spotted
the reason that we still ask the question? How about now? There are myriad reasons why somebody
who's making the call might not be on seeing with the patient. You might be calling on
behalf of a friend, a relative who's not with you. You might be working in another service
control room, like police or fire and you need our assistance with an incident or as we've seen
the ISEC and AML information just might not be that good. Some people inexplicably do still have
knockier brick phones. Although I've got to say fair play to them because I'm still proud of my
snake high score 20 years later, but yeah, sometimes the data that we get from them is just
just not very good. Time for the first and my interesting tangents. So I will cue my interesting
tangent music. What happens if you have no signal or you haven't paid your phone bill? Can you
still call 999? How does that work? You will have seen emergency calls only on your phone unless
you have an iPhone because this is an argument I'm still having with Apple to this day, but that means
your phone can't see your mobile network, but it can see other mobile networks. So it uses one of
those to contact the emergency services. However, when you do that, it doesn't pass any information
from your device to us. We see this as your mobile phone number, which obviously is not real,
so that doesn't give us any indication of where you are or who's calling, which is why we also
ask for your telephone number to confirm that we've received correct information from your device.
So that's how that works and it's extremely important that we double check the information
that we've given for that reason, but you don't care about any of that. For those of you just joining us,
you are dead and we're trying to prevent that from happening. So far, we know you're not breathing
and we've predicted a category one call. We know roughly where you are and we've asked for your
exact location. Next, we need to find your precise location and then while you wait, we're going
to try and get you some help, send you an ambulance and then give you some advice while you wait.
So we need to talk about the 11 seconds thing and we need to talk about why we're still asking
for the precise location and finding it. Because right now, the ambulance crew this will be
their mobile data terminal is navigating to this. These are the ordinance survey easings and
nothings of the call that we've received via ISEC. Later, we can have an argument about the
merits of X and Y coordinates versus Latin law. For now, just pretend the UK is a flat rectangle.
But it will be grand if we could turn that into something that means anything for our ambulance
crew. Unfortunately, all so for our call, handlers, CAD isn't Google. Our control room is
completely air gap from the public internet. So we have to rely on information that we have already
to find canonical addresses. We can't send them wherever the caller says. The address has to
exist. The address point has to be something we recognize. So we get our location data from the
ordinance survey, which is a great Britain's national mapping agency. They give us their product
called address based premium, which is their location, Gazette here for free. Thanks to the public
secretary of spatial agreement. Thanks ordnance survey. Which gives us the database every address
point in the UK. Later, we can have an argument about what constitutes an address point.
So we have every address point in the UK. Well, in Great Britain, I should say that's a
political thing I'm not waiting into. In our database that can be queried by call handlers.
So what's the address of the emergency? Bugger. See, the thing about Baker Street tube station
is no one knows where it is. I mean, people know where it is. It's there. But no one knows it's
full address. According to transport for London, it's not even on Baker Street. The official address
is on Marleybone Road. How is a member of the public going to know the address of Baker Street
station when TFL themselves don't have the full postcode on the website? We need to find Baker
Street station without having to enter a full address. Now, the CAD system can obviously match
on a partial address string. But if you type in Baker Street, you'll find the station and also
every address along this road here. Also, because the tube has been around for more than 160
years, there are many different canonical ways of referring to stations for of which appear in the
ordinance of a product. So it's a bit more difficult than you might expect. I'll tell you how I
fix the problem. Open data. Usually gets a woo. You open data geo people come on. Thank you.
It turns out that TFL will just tell you where all their stations are with coordinates. If you
ask their API nicely, I then scrape all of that information and turn it into one canonical way to
refer to stations I use U-slash G because it's fewer keystrokes than underground and we use the
coordinates returned by the TFL API to fill the database with the canonical location of every
tube station. The call handler can then just type in Baker Street U-slash G and it populates
with the full address on Marleybone Road and with the other half of the postcode. TFL, you're welcome.
We also do this sort of thing for the whole country's national rail stations which we get directly
from the Department of Transport, other transport for London services like the Overground,
the Elizabeth Line, etc. Our own ambulance stations because it would be exceptionally embarrassing
if we couldn't find those and these driver location signs that are on all of England's motorways
every 500 meters. We get them from the national highways agency. We use this tool that I built
to compile all of that information from the various sources and produce address entries
that we can then load into our system. We give them our own UPRN that starts with LAS because
they're not real UPRNs but we take in data from various sources, CSV files, APIs etc.
And we transform them into canonical address style records.
Another interesting tangent quickly, what happens if you get sick underground with no mobile signal?
There is now mobile signal on most of the London underground, however,
if you are without phone signal, you need to find somebody who works there.
They will use a London underground radio to contract their control room and then their control
room will phone us. However, if you're in a control room, you can't tell me where to go.
If you're a caller on a scene, I can ask you what you can see around you, but if you're in the control room,
you need to be able to tell me which of the three entrances to Baker Street station we need to go to.
Fortunately, TFL being the clever so-and-soes they are, have assigned a numerical code
to each of the entrances to Baker Street station. We take all of these into our address database.
We create records for each one. So the call handler can just type it in. This isn't a real one.
I'm not allowed to show you a real one, but they type into the district box because London doesn't
really have districts. We can argue about that later because it definitely does, but we don't use it
at the LAF. So we can type in the code and find exactly where TFL need us to get to. Anyway,
back to you and being dead, that's ticked off your precise location. So now we need to send you an ambulance.
So it's finally time to address the 11th seconds thing. We need to talk a bit about triage,
and we need to talk a bit about how you get your priority. We've talked about what the priorities mean,
but a call handler doesn't just get to pick one. They don't get to just choose what to assign you.
So we use one of the two triage systems that are approved for use in the UK in England.
I should really say there's MPDS, the medical priority dispatch system, which is a system of choice
here in Belgium. Also in about half of the English ambulance services, including the London
ambulance service, and NHS pathways, which is an NHS product. So it's only used in England.
It's used at the other half of services as well as on non-emergency medical advice service one or more.
After the talk, we can have an argument about which one's better, but MPDS is the one we're using.
London, and fun fact, we also contribute the most changes back to the MPDS in the world,
based on our clinical audit and research. In the MPDS, there are 35-ish protocols that
can go into essentially exactly what's happened. It has every possibility of why you might need an ambulance,
and that allows us to assign the priority based on the system. It spits out a triage
determinant code that looks like that. I would love to explain what it means, but I don't have time.
So whilst we may see you as this, the system sees you as this, but because the system sees you as
this, it knows the priority. There's a group in NHS England called the emergency called
Prioritization Advisory Group. They go by ECB, you'll be unsubvised to learn. The signs all
1,800 MPDS codes and the equivalent pathways, the priorities in advance. We loaded into a look
up table, and then the CAD can find you. And the CAD can prioritise you, sorry.
See where it says type code. This is a type code essentially. And that allows us to do automatic dispatch.
So now we know where you are, and we know you're a category one, CAD is going to start searching
for available ambulances using the mobile data terminals in the trucks. There's one, which transmit
their GPS information directly into CAD continuously. And then as long as that call exists in the
system, the CAD is going to assist the dispatcher in trying to find you an ambulance. Even if the
dispatcher hasn't opened the call yet. So that ticks off this bit, right? We've sent you an ambulance.
Yes, we have, but we can do a little bit better than some people in a big yellow van.
Each of the type codes also allows us to create a response matrix. I would love to go into this,
but I don't have time. You get sent a double crude ambulance, the standard big yellow thing,
but we also send various other types of units to do CPR on scene, provide other treatments,
et cetera. Don't have time to explain that, but they're so low paramedic respondent vehicles.
We need to make sure at least one person we've sent is a paramedic so that they can give you
what my boss has asked me to stop calling the good drugs. And we also send a volunteer responder
if we can to provide you that basic first aid on scene while you wait. One final thing, we
figured out where you are and how to get you help, but what are we going to do while you wait?
It's not like on TV dramas where you just make the call and then hang up and then the ambulance
arrives. I'm also not sure how film Mitchell plans to get an ambulance talking to his
lock screen there, but we digress. This is the MPDS instruction required to be given to all
callers after triage is complete. There are instructions that the MPDS contains that you give to
the caller to talk them through first aid. That can be all manner of things, including not having
anything to eat or drink, in case you need surgery later, bleeding the drill or for you who's currently
dead, it's going to be CPR. How do you take someone CPR over the phone if they've never done it before?
That's obviously a joke, but having said that, the British Art Foundation did produce a
Spotify playlist of songs that are the right BPM to do CPR to, Google Life Saving Beats and
save that to your phone later. Unfortunately I can't really show you the specifics because it's
all copyrighted and licensed and basically I'm not allowed to show it to foster. However, what I
can tell you is we essentially give you a crash course in CPR telling your where to put your hands
and all that sort of thing and then count out metronome style 1, 2, 3, 4 to make sure they're
getting the rhythm right. We can give all kinds of first aid over the phone as I said,
including bleeding the drill, use of an epipen or in a lock zone, even delivering a baby,
things we're going to buy is over the phone. I personally have delivered five babies over the phone.
When you do that, our clinical audit research unit give you this little badge. It's a little
stalk and that leaves on my work lying out, right? That's almost it. We've completed our list,
but in the words of so many apple keynotes, one more thing. Do you remember when we were talking
about the BHF a moment ago? That was kind of a check-offs gun. There is another geospatial data
set I want to tell you about and it is the circuit, the BHF's national defibrillator database.
This is the map of all the defibs around electromagnetic field, which is the hacker camp I
lasted this talkout because I've very lazily not updated the PowerPoint, but this information
is also available in an API and you know enough about me by now to know I love an API.
Because we've assigned you these type codes, CAD knows that you're in cardiac arrest and we can
program it to do other stuff, including dispatch a defibrillator. We get a data dump from the BHF via
the circuit API into the CAD system. So the call handler can tell you where the nearest defibrillators are
and if it's a defibrillator we've put there because we have given defibrillators to every tube station
a lot of public buildings in London will send an automated text to their security or because
studio and the defibrillator to us and to take it to the patient. So now that really is it.
So we do one more of these for all time sake and then I have to finish. What happens when it all
goes sorry I forgot the tangent music? There you go. What happens when it all goes wrong? What
about when there's a problem with the database with our connections? Many of you in this audience
will have experiences of systems that have been less resilient than you'd like them to be.
Working here is the first time I have ever seen a 100% uptime SLA, but it's an unfortunate reality
that outages happen. How do we cope? Well unfortunately a lot of these fancy geo stuff goes out
the window and we use this delightful publication. The geographers A to Z master map of London
we find the map reference on the page and we use the index to validate that the road exists
and is where we expected to be and then we give that map reference over the radio to the ambulance crew
so that they can be on the same page as us literally. Each ambulance has one of these in the glovebox
so they can refer to it if we're having issues. That's kind of a lie. We do do that, but also
usually when the CAD system goes down we've still got access to the internet or our local network
so we have a little web tool that sits on our network that can actually just query the
ordinance survey API because that's a lot easier. It's still generates the map reference and we
still do train people on how to use these and rely on them if the network doesn't work but
yeah those are kind of not true. As for the rest of it that's kind of a tangent on the tangent
we have to be able to operate the whole ambulance service on pen and paper. I find this personally
very fun everyone else finds this hell on earth. Don't know what that says about me but we write
down the call details in triplicate on these lovely carbon copy pads and we have a paper
flipped file version of the triage system so we can go through it with our computers. If a call
taken in our south London control room needs to go to a north London crew it's sent to them with
one of these things. For the young people in the audience this is a fax machine and please find a
grown-up to explain how it works and finally to make sure that the calls that we're already in the
CAD system at the time of the crash are dispatched and responded to a piece of software written by
yours truly. Copy is them to redundant work stations in each control rooms of in the event.
It can no longer see the CAD database they can get printed out onto those pink slips you saw
a moment ago. So now that everything all our tangents complete we've ended the story. If we
found you using open data, aided by the live geospatial information from your phone we use the
world's most popular structured emergency medical triage system which is a hell of a thing to say
so you can see why there isn't another. To identify what was wrong with you we got you the best
possible response based on exactly what had happened to you and everybody lived happily ever after.
Well not you you spent a month in the hospital having heart surgery but because you received
that early CPR and early defibrillation we were able to give you an up to 70% chance of surviving
your cardiac arrest and that is how to save a life. Do I have time for questions?
Does anyone have any questions?
Yes the AML. Yes so that works based on the GSM standard so when your phone knows that it's
dialing an emergency number it texts that to in UK it texts it to BT here it will text it to
whatever telecoms agency is responsible for transmitting that to the emergency call handling
centers but it's kind of pre-programmed configuration in the phone based on the GSM spec.
Over here. So you've written a bunch of these tools for the actual technologies behind
how this works but you mentioned but you also had done this back call for itself.
Is that common thing when we love the AML service? Well there are exactly two of us that have
done that. Unfortunately she's on holiday. The question was is it a common career path
in the London AML service to start as a dispatcher as I was and then go on to write the tools
and technology myself? I've been very very lucky. Is the answer to that question? There are
two CAD and technical leads at the LF but yeah I'm one of them but a lot of people do go on to
work in other areas of the service like IT like systems or they go and work in operations management
or they go out on the road. A lot of call handlers will go out on the road because they want to
actually get stuck in and help. Over here.
Yes so when you call from underground where there's signal on the London underground etc
is the first approximate location useful. Yes we've done a big bit of work with the mobile networks.
There was a news story a while ago that said emergency services are blocking the road out
of 4G on the underground sorry that was me that was my fault genuinely was me but that's because
we had them develop a version of the ISEC system that transmits directly to us that you're in a
tube station so if you call it doesn't actually use your GPS location because you're going
through a repeater station that's on the underground it comes up and says you are at Baker Street
station on our end so we can confirm that so it's very usable. Behind you how do I find location
if someone calls from a landline BT send through the registered emergency address which is usually
where the bills go to unless but if you have like a VoIP a SIP landline in the UK you have to
register an address for that landline in case of emergency calls and that just comes through
as text and matches one to one with the address based product unless you're in a Markson Spencer
because they've all registered their locations to their head office so you can call from any
Markson Spencer shop in the UK and it all comes through to their head office not not great over here.
Thank you.
Non-English speakers and people with disabilities so we have access to a 24-7 translation service
into a protection service for about 200 odd languages I think and they will help us if the
person can speak but not speak English if someone is unable to speak you can also send SMS text messages
to 999 in the UK or we accept teletype calls where a relay a system will come on the line from
BT and do the typing and talking depending on what the caller is able to do.
In the front of the WIFI calling in the round of a university for example.
WIFI calling is kind of similar to the landline side of it the location comes from
through so I think it tries to send your AML over the WIFI connection because we're doing it with HCCB now
but usually the cell companies that enable the WIFI calling have kind of location that comes through
that's a bit like the ISEC location but not quite as good. It's complicated as the short answer
but it works most of the time because it can use the AML in the back.
What's the nature of the argument I'm having with Apple about emergency calls? In the UK,
in other countries when it's emergency calls only it comes up with SOS on the phone in the UK it just
comes up with no service. We would love it to be the other way around so people know they can make emergency calls.
Was there another hand?
Dad.
Ratio of proprietary and open source tools that you use ratio of proprietary and open source tools that
I use got a good question mostly proprietary. I would say unfortunately however we're trying to
change that with a much open data as I can put in the database but most of what we use for location
certainly is the ordinance survey so that's proprietary. In the back.
If I'm writing scripts for API, do I get to publish those or do I have to live on my machine?
A good question we are still working through that. Most of them I think are underground copy
rights or I can publish them but there are some things that we do that are internal because
they map to processes that we don't really own like the London Underground numerical codes so I'm
not allowed to share that information over here.
Did we consider open street map? We are using open street map for a new project which we should
be rolling out very soon for finding parks and squares and open spaces and it's definitely something
we're considering. We have to legally we have to rely on the ordinance survey in the first instance
but anything we can use from OSM to supplement that we will definitely.
In the back. The question was I've heard the police use what three words does that apply to
the ambulance service if you'll just excuse me. I just have to pop this on the screen.
So we do accept what three words locations at the ambulance service most emergency
services in the UK do. We don't love it because obviously it's not tremendously accurate and it
requires the caller to do something so if we can't find you we don't like encourage the caller
to the call handler to send you the what three words link but if we're given a what three words
address we can or location we can geocode it we have their API and they do let us use it for free.
Thank you very much.