Limited use of Lights and sirens

[jrm818]

This is all the hand holding you are getting. I just did a quick search and found several good articles.
http://scholar.google.com/

Working in EMS and on Specialty transports for several years, I also have experience that tells me what patients go through. It's not rocket science, just a little commonsense.

Thanks for removing the personal shot (serious).

I didn't need any hand holding. I'm familliar with google scholar...just as a for instance...type in "'lights and sirens' stroke" The first page of results has one vague reference to transport with L/S...every other article on the first 2 pages of results deals with dispatch priority not transport with or without lights and sirens. The closest to a mention of ambulance transport time is just listing net time with patient, the effects of prehospital recognition on stroke, and the fact that pt.s presenting with stroke-like symptoms to an ED get CT's faster than pts comming by POV.

The point is, there is no good research that I've yet seen which directly addresses the use of lights and sirens transport with stroke patients.

There is (decent to good) evidence that early treatment = better outcome in strokes. Insofar as in many locations L/S will reduce transport time by signifigant amounts, it is logical to assume that absent any other intervening factor (eg stress...see below), L/S will improve outcomes.

Stroke team activation is obviously important. no they don't materialize, but in a properly setup system, they are ready when the ambulance shows up. Door to CT times are important...but if you don't hit the door for 40 minutes instead of 15, than patient outcome may well be worse.

So from the premise that L/S decreases onset-treatment times, which is good. L/S is a good practice, unless there is a signifigant evidence supported detriment to such transport. Accident rates are certianly valid, but proper driver training and re-enforcement can reduce those risks. In my case I' don't drive like a nut, so i don't think the increased accident rate is an accurate representation of the risk to me and my patient individually.

I understand the stress response arguments - they would be an intervening factor that might outweigh the time saved by L/S driving. I don't agree that they do based on everything I know about the effects of stress on strokes. I will readily grant (and already have) that stroke outcome is worsened by stress responses - especially the inflammatory, hyperglycemic, and hyperthermic variety.

The argument that L/S increases stress is not enough. This issue is more complicated than that, and the quantity of stress matters. I've seen the data for time to treatment, I want to see the data (actual numbers, not generalizations) for stress responses. I don't believe such data exists specifically applied to L/S transport. There is a lot of animal data about stress and stroke outcome, but it is mostly chronic or subacute stress prior to stroke. I knew about this data already, and spent the last hour or so looking again to confirm that...I didn't find anything too specific to the issue at hand.

There is data which indicates that there is a stress response to stroke regardless of psychological stress (which is what L/S is). Thus we are not comparing stress from L/S to an unstressed CNS, rather the incremental additive stress form L/S transport to the stress that already exists from the physiological response to stroke, underlying pathologies and disease processes, possibly a freaked out family, psychogical disturbance due to strange neurologic symtoms (e.g. not being able to talk is pretty darn stressful), stress from the arrival of an ambulance, quick moving providers, phone conversatoins with all kinds of medical gibberish, going in an ambulance, exposure to a hospital, etc.

I find it hard to believe that hearing a siren in the back (when the patient likely expects a siren to go with an ambulance anywyas) is going to make that much quantitiave difference in net stress levels. In the absence of data (and for this, I will ask for citations. I've looked, and found nothing on point about stress increases in patients (plenty about providers) when brought by ambulance), we are left to guess...and that's my guess.

So, from my perspective...for all you evidence based types out there
decent-good evidence supports decreasing onset to treatment times
good evidence says stress is bad in a stroke, but thats prior chronic stress, acute stress almost certianly is bad, but exists anyways
little-no evidence that L/S has any effect at all on overall stress levels

To me that adds up to the evidence pointing to L/S (in systems where it make a signifigatn difference in transport time) as possibly helping outcomes until more evidence clearly demonstrates a detriment.

Fire away...i may not answer anymore tonight. Tomorrow is another day...


Note: I realize I'm not paying any attention to MI's AAA's or the other things I mentioned. I'll admit I'm not nearly so familiar with that data, and I don't have time to debate each condition individually, so i picked strokes as my example condition. I got blasted for advocating strokes to L/S too, so I figured it's as good a condition to defend as any...

 

[jrm818]

http://www.medscape.com/viewarticle/582754

Good article on Trauma and scene times.

Can you post a citation? Curious what this is. Link doesn't work for me the way I log into things...

 

[AJ Hidell]

Okay, you're getting way too hung up on the term "stress", without seeming to understand exactly what it means. I understand that the understanding of physiology taught in EMT school -- as well as most paramedic schools -- is painfully inadequate, so this is of no surprise. However, regardless of your educational background, your common sense should kick in to compensate here.

Again, do you not understand the dangerous and potentially fatal effects that increased heart rate and increased blood pressure can have on your MI, CVA, or AAA patients? Do you really believe that a few seconds or minutes of time saved could possibly negate that risk? Do you think it is okay to increase the rate of their bleed, or the damage of their infarct just to get them to the hospital faster? That's like the guy I pulled over for speeding once who claimed it was because he was in a hurry to get to a gas station before he ran out of gas. Does that make any sense on any level? No! Use your head!

 

[trevor1189]

my opinion for what it's worth

It looks like Pennsylvania is proactively trying to decrease L&S response to less than 50%. According to the PA BLS Protocols updated 11/1/2008.

You can check out guidelines for L&S response in PA here: http://www.dsf.health.state.pa.us/health/cwp/view.asp?a=170&Q=231878

By clicking the "Statewide BLS Protocols Effective November 2008" link and looking at pages 16-18 of the pdf file.

I agree that an ambulance shouldn't be flying down the highway L&S going. At least where I live, bumpy roads = not fun for people in the back of the ambulance. But I also think that ambulances should be able to use lights and sirens to proceed through lights instead of sitting there waiting if time is sensitive. Where I live, people do pretty good about getting out of the way for emergency vehicles and even blue lighters. I also think something to consider is resources. If you live in a small town, with limited EMS personel and equipment the longer it takes for the ambulance to get back in service the longer the next patient might have to wait. If there are only one or two ambulances available and both are out it seems like they should be trying to get back in service and available as quick as safely possible.

But, what do I know. I'm not even an EMT yet.

Just my 2 cents.

 

[jrm818]

Okay, you're getting way too hung up on the term "stress", without seeming to understand exactly what it means. I understand that the understanding of physiology taught in EMT school -- as well as most paramedic schools -- is painfully inadequate, so this is of no surprise. However, regardless of your educational background, your common sense should kick in to compensate here.

Again, do you not understand the dangerous and potentially fatal effects that increased heart rate and increased blood pressure can have on your MI, CVA, or AAA patients? Do you really believe that a few seconds or minutes of time saved could possibly negate that risk? Do you think it is okay to increase the rate of their bleed, or the damage of their infarct just to get them to the hospital faster? That's like the guy I pulled over for speeding once who claimed it was because he was in a hurry to get to a gas station before he ran out of gas. Does that make any sense on any level? No! Use your head!

Actually I think the view of stress I'm taking is a bit more complex that what you assume. Especially in the case of CVA, which is addressed above, stress in the form of increase HPA activation, local and generalized inflammatory factors, local as well as systemic vasoactive factors are important. Heart rate and BP are just the sympathetic responses (I'd even venture to say that the most important symp. response may be glucose mobilization in the context of cva, rather than the ones you mention...hyperglycemia is bad juju for strokes)...but the effects of stress on infarct size and the cellular reactions to infarct involve responses to a lot more than just raised blood pressure. A lot of the problems in stroke comes from local dysregulation of the vascular system anyways...I dont know how much difference arterial blood pressure alterations make given that semi-decoupling of vessel pressure in the brain from systemic pressure. When I say "stress" above I'm referring to all of these processes...sympathetic, inflammatory, HPA and secondary cellular-reactive, etc.

I think I made it clear that I understand that stress is bad...both the local and inflammatory version and the sytemic sympatho/adrenal version. My point is that these are not only psychologically mediated. The physiological stress of CVA (or whatever) alone will cause a lot of these processes. You get a stress response even in the absence of psychologicla stress.

Much of the psychological stress is innate to the emergency condition. In order for you make this "common sense" arguement that L/S is bad for people, it needs to be clear that the increment of stress which is caused ONLY by L/S transport, and not by the other circumstances, contributes significantly to the overall level of stress (measured either by catecholamine activation , HPA activation, inflammatory response, whatever "stress" you choose) to such an extent that removing the L/S unique stress changes patient outcome. I simply don't see the data for that argument.

Read that carefully...I will happily grant that stress in pretty much any form is bad for these patients. But dealing with the emergency is stressful...if there is an intervention like L/S transport that can be performed with only a relatively small increase in stress but a relatively larger positive effect on outcome, it seems justified. The question is simply how much stress does L/S add, and how much benefit does L/S bring. There is data for the second part of that...not so sure about the first. without data we can only speculate on the added stress of L/S...and I simply don't think its that big of a deal given the magnitude of the stress response that is unrelated to hearing a siren. In the absence of data we are all free to speculate...

As to the difference made by seconds...of course seconds don't matter for almost any condition. I'm talking about cases where L/S makes a difference of 15 minutes or more.

In that case...can it change outcomes? Yes, I think it can. And the difference between your "common sense" argument against increasing stress and mine is that there is evidence that demonstrates better outcomes the sooner CVA is treated (assuming they can be treated). How much difference? for an individual patient..who knows. but in general, I feel pretty confident speculating that less transport time can acutally result in signifigantly improved outcomes.

And again, i realize I'm ignoring MI and AAA. I don't have time to address everything, so for consistency I'm sticking with strokes.

 

[Ridryder911]

I think you can't see the forest for the trees. Simple. Hook up the monitor and closely monitor the blood pressure. Now, proceed with l/s and without. Research has demonstrated even experienced emergency providers blood pressure and pulse rates increased as much as 25%. Remember, these were experienced providers.

Now, let's use common basic hemodynamics. Increased HR X Increased SV X Increased TPR = Increased cardiac output and increase ICP and vessel pressure. Just watch a CVP and art line.

Now, how much time is really saved? What difference is 4 minutes really going to save? There is more questions as if with l/s actually save time? And if so, really how much, if it is performed safely? As well, more and more centers have increased their door to option from three hours to six hours.

L/S are for usually reserved for those that do not know what to do. There is those very, very few times that I respond back with l/s. Triple A that has a code brown, Cardiac Arrest that occurs with a code brown.... okay there is something related here.

R/r911

 

[AJ Hidell]

Much of the psychological stress is innate to the emergency condition. In order for you make this "common sense" arguement that L/S is bad for people, it needs to be clear that the increment of stress which is caused ONLY by L/S transport, and not by the other circumstances, contributes significantly to the overall level of stress (measured either by catecholamine activation , HPA activation, inflammatory response, whatever "stress" you choose) to such an extent that removing the L/S unique stress changes patient outcome. I simply don't see the data for that argument.

It's a fallacious argument to make. What you are saying is, since other things cause stress, there is no reason to avoid any of them. That's like saying since our house could be destroyed by a tornado, there is no reason to reduce our risk of fire. It's a nonsense argument. If the sympathetic response were the only "stress" we had to worry about, you'd actually have a better argument. But, since you admit that it is only one of many stressors, it is more important than ever that we reduce as many of those as possible.

Regardless, we can only prevent those stressors that we ourselves induce. Since WE induce the stress of a code 3 run, WE are responsible for preventing it.

 

[jrm818]

I think you can't see the forest for the trees. Simple. Hook up the monitor and closely monitor the blood pressure. Now, proceed with l/s and without. Research has demonstrated even experienced emergency providers blood pressure and pulse rates increased as much as 25%. Remember, these were experienced providers.

R/r911

Like this study? (acutally the first I've found to address this issue on point. The authors claim it actually is the first..I believe them)

Emergency medical service transport-induced stress? An experimental approach with healthy volunteers Resuscitation, 2001

I'll summarize the results:

Found that transport down stairs is more stressful than the transport to the hospital while going L/S in dramatic fashion. They measured Epi NE HR and BP.

EPI and NE increased signifigantly for transport in a stair chair, EPI increased significantly for transport in the ambulance, although EPI in transport was significantly less than EPI while going down stairs.

NE increased in the stair chair, and was acutally lower than control during ambulance transport (I don't like the authors explanation for this one, although it probably hurts my argument. I think the decrease is prob. due to the secretion of EPI rather than NE from the adrenal medulla now that the HPA axis had time to stimulate the conversion, and thus the decrease in NE doesn't represent a decrease in stress....but who asked me)

HR went up a bit during transport...much more during stair chair. BP changed overally by 4+- 2 mmHG, but wasn't plotted across the time points.

Overall the least stressful part of the whole experience was transport in an ambulance going L/S with intentional speeding, hard breaking, and u-turn making.

To me that supports what I've been saying. Will there be in increase in stress? Sure, but it is NOT unique to L/S, and removing L/S probably won't result in very much clinically relevant decrease in stress.

Plus..these were healthy volunteers with no other sources of stress. With a real patient I feel like the stress from transport will be overshadowed by the stress from their emergency..but there's no data to support or refute that.


the time window extension argument:

fine...tpa can be given at longer time points. It doesn't matter, my argument was never based on tpa vs. non-tpa (although it could have been I suppose) - outcomes are still better the earlier it is given (and that was mostly studies using the 3 hour time limit). It is not true that outcome at 6 hours is the same as outcome at 3. The cliche time= cells is right on in this case.

 

[Sasha]

You can't avoid transporting down the stairs, unless you toss the patient out of the window or there is an elevator.

You can avoid the unncessary stress of a lights and sirens transport.

Plus..these were healthy volunteers with no other sources of stress. With a real patient I feel like the stress from transport will be overshadowed by the stress from their emergency..but there's no data to support or refute that.

Put yourself in your patient's shoes. What do you think when you see an ambulance just lazily driving along? "Oh, it must not be that bad!" but when you see a truck screaming down the highway towards the hospital, you think "Yegads! An emergency!", right?

So, if you were a patient and the paramedic decided for a L/S transport, what does that tell you about YOUR condition? Do you start to get worried and stressed?

Plus..these were healthy volunteers with no other sources of stress.

You miss a key factor in the study, in my humble opinion. The volunteers knew they were healthy, nothing wrong. The patients don't know what's going on. The unknown can be quite a stressful thing.

Can you provide a link to the study?

 

[jrm818]

It's a fallacious argument to make. What you are saying is, since other things cause stress, there is no reason to avoid any of them. That's like saying since our house could be destroyed by a tornado, there is no reason to reduce our risk of fire. It's a nonsense argument. If the sympathetic response were the only "stress" we had to worry about, you'd actually have a better argument. But, since you admit that it is only one of many stressors, it is more important than ever that we reduce as many of those as possible.

Regardless, we can only prevent those stressors that we ourselves induce. Since WE induce the stress of a code 3 run, WE are responsible for preventing it.

Strawman argument. I never said we should not avoid stresses. We should. But if an intervention has positive outcomes, those positives are weighted against the negatives of increasing stress.

The presence of other stressors does not make L/S unique stress more potent. The opposite in fact...the system can only modulate within certain limits...as stress increases due to non-L/S factors, whatever system we are talking about will get closer to its upper limit. At these limits it takes very large changes in stimulus to get measurable effects.

For example...you see a hungry bear...HR and BP go way up. Bear pulls out a gun. HR and BP might go up a little more....but the increase will be less than it would if you had seen a gun pointed at you sans bear because they were both pretty high to begin with.

In the same way the effect of L/S transport will likely (although maybe not...again...no data) be overshadowed by the other stresses going on...like being brought down stairs on a stair chair. If we were really worried, we would start sedating our patients prior to transport.

OK that really is it for the night. Its been fun...back tomorrow maybe..

 

[AJ Hidell]

You seem to be seeing individual points here, but failing to do the math to add them up in context. The math is simple here; less = better. And if you add stress, you had better have solid, proven justification for it. You do not.

This whole argument is sounding just like those who continue to argue that MAST pants are good because they maintain BP to the hospital. You're basing your argument on empirical data that is not scientifically validated as helpful.

 

[VentMedic]

Like this study? (acutally the first I've found to address this issue on point. The authors claim it actually is the first..I believe them)

Emergency medical service transport-induced stress? An experimental approach with healthy volunteers Resuscitation, 2001

I'll summarize the results:

Found that transport down stairs is more stressful than the transport to the hospital while going L/S in dramatic fashion. They measured Epi NE HR and BP.

EPI and NE increased signifigantly for transport in a stair chair, EPI increased significantly for transport in the ambulance, although EPI in transport was significantly less than EPI while going down stairs.

NE increased in the stair chair, and was acutally lower than control during ambulance transport (I don't like the authors explanation for this one, although it probably hurts my argument. I think the decrease is prob. due to the secretion of EPI rather than NE from the adrenal medulla now that the HPA axis had time to stimulate the conversion, and thus the decrease in NE doesn't represent a decrease in stress....but who asked me)

HR went up a bit during transport...much more during stair chair. BP changed overally by 4+- 2 mmHG, but wasn't plotted across the time points.

Overall the least stressful part of the whole experience was transport in an ambulance going L/S with intentional speeding, hard breaking, and u-turn making.

To me that supports what I've been saying. Will there be in increase in stress? Sure, but it is NOT unique to L/S, and removing L/S probably won't result in very much clinically relevant decrease in stress.

To read medical literature one has to understand its weaknesses as well as its strengths. That study was done on healthy individuals and even the authors themselves admitted that "who wouldn't relax" even if it was in the back of an ambulance after the climb down the stairs. Since these were healthy individuals they did not have the additional stress of disease processes and the anticipated stressors of the trip to the hospital.

Try this article:
Effects of Emergency Ambulance Transportation on Heart Rate, Blood Pressure, Corticotropin, and Cortisol
K Witzel

If you have university access, it is in the Annals of Emergency Medicine.

Or, try this one:
The influence of the mode of emergency ambulance transportation on the emergency patient's outcome.
Eur J Emerg Med. 1999 Jun;6(2):115-8

Witzel K, Hoppe H, Raschka C.
Department of Surgery, Herz-Jesu Hospital Fulda, Germany.
Emergency transport by an ambulance can cause considerable psychical and physical stress for patients. We determined the haemodynamic and endocrinological values of 54 healthy volunteers subjected to one high speed emergency transport and one smooth transport. There were significant differences in all measurements: heart rate (p < or = 0.001), blood pressure, cortisol (p < or = 0.01), prolactin, somatotropine and ACTH between the two modes of transportation. We hypothesize that the additional stress of high speed ambulance transport particularly in patients with acute cardiac disease may result in additional morbidity.
PMID: 10461554 [PubMed - indexed for MEDLINE]

 

[triemal04]

You seem to be seeing individual points here, but failing to do the math to add them up in context. The math is simple here; less = better. And if you add stress, you had better have solid, proven justification for it. You do not.

This whole argument is sounding just like those who continue to argue that MAST pants are good because they maintain BP to the hospital. You're basing your argument on empirical data that is not scientifically validated as helpful.

I'm not going to argue that the use of a siren doesn't increase stress, or that being tossed around in back won't either (of course, even while driving code 3 that shouldn't happen; that it does is a great indicator that someone needs more training and/or needs to be fired). And the studies that have been cited have shown that pretty well. But that isn't neccasarily the end of it.

While the bodies responce to stress can make multiple problems worse, as shown in a couple studies, none seemed to take into account the things that we should be doing to help alleviate both the stress responce, and the initial problem. (granted, this can't be done for everything). An MI for instace...nitrates, beta blockers, morphine/fentanyl...all can help to decrease the bodies natural responce to both the stress of the event, and whatever increase there is from hearing a siren. It's definetly not perfect, but I believe it can be effective.

Really the only time we should be going code 3 to the hospital is if the issue is one that we can't correct in the field, only sustain to one extent or another, and will lead to, at minimal permanent disability and very likely death. At some point it does either become use a means of rapid transport and try to mitigate any additional problems caused by that, if any, or transport normally and allow the problem to continue to worsen. Either way has it's pluses and minuses, and for both it's knowing when and why to do it that is the hard part.

And going code 3 to save a few seconds is ridiculous.

 

[ffemt8978]

Something else to consider...

In town, the only place that code 3 driving gains you time is at the most dangerous part of your trip...intersections and against the light.

 

[firecoins]

Something else to consider...

In town, the only place that code 3 driving gains you time is at the most dangerous part of your trip...intersections and against the light.

that is true. Intersections and heavy traffic are the 2 places where it is effective. I don't even use them for jobs late nights when there is almost no traffic at all. What's the point?

 

[ffemt8978]

No point, other than this is a discussion about driving code.

 

[JPINFV]

Here's something else to think about in terms of intersections. How much of the time it takes to stop, clear the intersection, and snake your way through any traffic stuck and stopped inside the interseciton? Now how much time does it take to just sit behind the limit line and wait for the light to change? The difference is probably a few seconds.

I've always wondered, given enough money to insure 100% of lights can be preempted (e.g. opticon), what the difference between l/s, opticon without l/s, and regular transport.

 

[firecoins]

Here's something else to think about in terms of intersections. How much of the time it takes to stop, clear the intersection, and snake your way through any traffic stuck and stopped inside the interseciton? Now how much time does it take to just sit behind the limit line and wait for the light to change? The difference is probably a few seconds.

I've always wondered, given enough money to insure 100% of lights can be preempted (e.g. opticon), what the difference between l/s, opticon without l/s, and regular transport.

l&s at an intersection probably saves us 45 second to a minute. We have long lights here.

opticon w/o l&s would work.

 

[mycrofft]

Heck, code 3 doesn't work here a lot of the time.

Between air conditioners, heaters, sound systems, cell phones and tinted windows, many drivers do not know you are coming.

The difference between driving thirty and sixty in city traffic means higher lateral G force on turns, rougher ride crossing speed bumps and potholes, and thirty more miles an hour in combined speed accidents with careless drivers. Your hapless partner is immobilized at times trying to stay upright. I once saw a MICU nurse drive a Bristoject Epi needle into her upper lip when my otherwise good partner/driver took us across some RR tracks in a Caddy and she had just unsheathed the needle. (Remember, this was in Bedrock and Barney Rubble was out dispatcher).

I only remember reading one mention above about inclement weather. Since safe drivers lower their driving speeds in icy wet snowy foggy dusty conditions, look to your ER mortality reports for those periods and see if more people die because drivers went slower. (Betcha there is no difference regarding cases experiencing this "delay" of care).

 

[medic417]

Where do most ambulances crash runnig L&S? Is it at the intersections that they rush thru to save a few seconds?