Response time - what is ideal?

[medicsb]

I find myself thinking about this, particularly when driving around, because it seems to be such a controversy. I'm always curious how far I can travel in my personal vehicle, generally following traffic laws (yes, I tend to not follow the speed limit and I do roll-through at some stop signs). It is often acknowledged that most EMS incidents are not true emergencies and the true emergencies are not as time sensitive as the lay-person might perceive. So, we generally know that response times may be over emphasized. But, nonetheless we have to show up at some point and the public expects/demands a speedy response.

What would the ideal response times be? Should it vary by system design (e.g. all-ALS vs. tiered vs. first response vs. no first response, etc.) and geographical area?

My take is that BLS should be the fastest component, whether it is FD-based first response, PD-based, or a volunteer responding in their POV.

ALS response, I think can be more relaxed.

I think times will and should vary by population density. The more dense the population, the more people you can reach in a smaller distance traveled, but average speed will be less than in area where the population is more spread out.

This is generally what I think as being ideal based on observation of travel speed in different setting (per my garmen... 20-24 in urban, 30-35 in suburban, 40-45 in rural - these based on moving time, not with stops counted.)

For all systems: a reflex time of 3 minutes. (from call to unit responding)

I'd propose for urban and dense suburban (say, >1500-2000 per square mile):
4-6 minutes for first response
6-8 minutes for BLS ambulance
8-10 (maybe 12?) for ALS

For suburban (less dense, <1500/sq mi)
6 for first response
8-10 for BLS ambulance
10-12 for ALS

For low density suburban, near rural (<500 sq/mile)
8 min for first response
10 for BLS
14 for ALS

For rural (<250/sq mi; of course, the closer the population density gets to 1, the longer the response time)
10 for first response
12 for BLS
16 for ALS

I'm more interested in the questions I posed; I'm not too interested what people think of what I think is ideal, but would be interested in what others think is ideal and thoughts on the subject.

Should we we use fractile response time or should we use medians? Should fractiles be 90%, or should it be less?

I guess we'll see where this goes (if anywhere)...

 

[Aidey]

What are your numbers based on? And why are they based on that?

 

[Bullets]

Population density is 3k/sqmi
Average Response time from dispatch to arrival is 6 minutes
Average time from enroute to arrival is 4 1/2 minutes

I think thats pretty good

No SSM, no coding calls, just straight staffed house system

 

[cprted]

The accepted North American standard for EMS response to priority calls in urban areas is <8mins. I don't know where that number came from, probably straight out of the air. There is no medical evidence to suggest reducing response times or code 3 driving actually have an impact on patient outcomes. But it makes people fell better when we come screaming up with the lights are sirens on.

Our service has a 90 second chute time requirement (crew notified to unit enroute) for duty crews.

 

[medicsb]

What are your numbers based on? And why are they based on that?

Observation and assumption. Because there's not a whole to base anything on in terms of response times.

I think, and often make it known, that paramedic experience is far more crucial to patient outcomes than most paramedics and medical directors acknowledge. In my opinion, the goal of ALS is to cover as much population as possible to enhance frequency of contact with sick patients.

I've noticed, via use of my GPS, that when I drive around Philadelphia, my average speed (with stop lights, stop signs, etc.) can range from 15-25 miles an hour. When I look at the moving speed average (excludes stop time, which is more typical of a responding vehicle), the average speed is around 20-30 (again, depends on the road and traffic). When I'm out in the suburbs, the average speed is faster as lights and stop signs are more spread and speed limit is higher.

Anyhow, 10 minute response time at 22 miles an hour is 3.6 miles. 3.6 squared is 13.4 square miles... If you're population density is around 6000, you can cover ~80,000 people.

12 minute response at 30 mph is 6 miles distance... 144 square miles of coverage, which if assume a population density a around 550, that medic unit could cover ~80,000 people.

Anyhow... This is all based on very general assumptions. We know that density is not constant and can vary from town to town and the range will increases with every additional sq. mile up to a point. This breaks down when you consider that a truck could be cancelled on one side of their coverage area and then have to respond to the other side and have to travel a much longer distance. So obviously there needs to be overlapping response area and some redundancy. And of course, triaging of calls and then patients would be necessary in order to target ALS to patients that actually need ALS. Anyhow, this is not completely thought through on my end and I know there a holes in my assumptions, but I'm more interesting in hearing what you think it should be or how competing interests should be handled (public perception vs medical reality), etc, etc.

(My assumption for allowing longer ALS response is that BLS can manage most of real life threats with basic skills, which are more likely to save the patient - cardiac arrest w/ CPR and Defib, anaphylaxis with an epi-pen, opiate overdose with manual ventilation, severe trauma with rapid transport, etc.)

 

[Aidey]

My comment wasn't to get the you to think about the technical aspects of driving, it was to prompt some examination of the necessity of having someone on scene within X number of minutes. What is the point of having someone there within 6 or 8 minutes vs 12 or 16?

 

[Chris07]

I think the point of fast response times is more to benefit an EMS system's public image than it is to benefit the patient. All the general public knows is that they are entitled to EMS and expect a fast response time. Why do they expect a fast response? Because when John Q Public is having what he deems "an emergency", he expects to see his tax dollars at work and see fire engines and ambulances race to help him.


It's all for public perception, IMO and only for patient benefit in a limited set of cases (like multiple GSWs, severe TCs...but then again...how often do they occur compared to the "may back has been hurting for 4 months" type calls)

 

[medicsb]

My comment wasn't to get the you to think about the technical aspects of driving, it was to prompt some examination of the necessity of having someone on scene within X number of minutes. What is the point of having someone there within 6 or 8 minutes vs 12 or 16?

I was discussing that rationale for different response time standards, not necessarily technical aspects. As far as why X vs Y minutes, I think its a matter of balancing public perception, medical necessity, and optimizing resources. I do think, despite most incidents not being actually emergent, that responses should be based, to some degree, on time sensitive emergencies. EMS has to get on scene at some point.

Anyhow, see my first post and the questions there.

 

[Handsome Robb]

The accepted North American standard for EMS response to priority calls in urban areas is <8mins. I don't know where that number came from, probably straight out of the air. There is no medical evidence to suggest reducing response times or code 3 driving actually have an impact on patient outcomes. But it makes people fell better when we come screaming up with the lights are sirens on.

Our service has a 90 second chute time requirement (crew notified to unit enroute) for duty crews.

Didn't the AHA kick something out a while back in regards morbidity and mortality referring to ALS within 8 minutes of a cardiac arrest? Not trying to argue, I can't remember if that was legit or if I'm making it up in my head. Early CPR and defobrillation is the key, one of the few times what we're doing is truly time sensitive.

60 second mandatory chute time here.
8 minutes 29 seconds for priority 1s from the time the address is entered into the CAD (goes for all times.)
10 minutes 29 seconds for priority 2s.
30 minutes for priority 3 and 4s. (3s are non emergent 911s, 4s are non emergent IFTs.

DOH here kicked those times down to us, we didn't make them.

 

[medicsb]

Didn't the AHA kick something out a while back in regards morbidity and mortality referring to ALS within 8 minutes of a cardiac arrest? Not trying to argue, I can't remember if that was legit or if I'm making it up in my head. Early CPR and defobrillation is the key, one of the few times what we're doing is truly time sensitive.

They may have made that recommendation, which, if I recall correctly, is based on ONE study done King County, WA back in the late 70s when BLS was just CPR and only ALS could defibrillate (http://www.ncbi.nlm.nih.gov/pubmed/430772).

Here is presentation from the Gathering of the Eagles about response times:
http://gatheringofeagles.us/2013/Saturday/Blackwell-ResponseTimes.pdf

 

[johnrsemt]

here depends on where the run is:

I have had less than 1 minute (covering tests with EMS on site)

to over an hour (25+miles of rough dirt roads)

Usually ALS is first response with fire backup on all EMS runs

 

[Trailrider]

Correct me if I am wrong,but I think the majority of of major metro operations aim for 8-10 mins response time. With that said, there are way to many variables that might affect response times such as weather,traffic, team availability etc etc and the list goes on. I would imagine for people living in rural settings would have a little bit of a wait time for an ambulance, as they are in a less populated area. I am currently looking into research on crew safety and response times and if in fact speeding to calls will actually save time,and or jeopardize more people on the road etc etc. It's quite a study...

 

[DrankTheKoolaid]

That is a VERY area specific question. When people say rural that means different things to different people. And the more truly rural an area gets the payer mix is likely going to predominantly become medical/medicare/Medicaid which means reimbursement is going to decline which means less funding for units on the streets. This is going to drastically increase response times.

Urban studies are great for urban areas but are absolutely useless for the rest of the nation and mean absolutely nothing.