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As someone who also has first hand experience with a severe lightning strike (that left one dead and 11 hospitalized) and on a separate occasion saw a lot of people with hair sticking straight up (we ran to our cars before lightning struck that time), I second this. Don't assume you're safe because you're not near a high point. Lightning strikes wherever. And never, ever, ever stand under a tree. They make great conductors, but your body (a sack of salt water) is an even better conductor, so the lightning jumps to you. Last, lightning strikes are one of the cases where CPR can be effective. The body is still well-oxygenatd, but the heart may stop from the shock, so keeping blood circulating can save a life.

One other thing to be aware of, one the injuries that lightning causes is blindness (temporary but possibly lasting a couple of days). Several of those closest to the strike were blinded - it was described to me as a sunburn of the retina, where vision is not restored until the burns heals. That may not be medically accurate, but describes the experience they went through.

Glad you were unscathed (assuming).

Excellent point about CPR and blindness as well.

Seems like an excellent argument for having an AED available. (I'm really torn; it's just at the price point where buying one without any particular risk factors seems crazy, but EMS in the east bay tends to suck.)

(except, I just checked on eBay; a surprising number of decent machines for <$500, allegedly pulls from gyms or hospitals. I wonder how hard it is to test and recertify, and also how hard it is to figure out how many of them have just been stolen.)

The idea of a sub $500 AED from eBay makes me feel very nervous.

Assuming it hasn't been opened and screwed with (which should hopefully be apparent from tamper-evident case construction), it should have a fairly comprehensive self-test built in. There's a pretty in-depth tear-down of one on youtube[1] that describes some of the test aspects.

Assuming it does pass, it's probably better than none at all, although in the worst case the person trying to use it is wasting time with it when they could be giving you CPR. Definitely a tough call.

[1] https://www.youtube.com/watch?v=pn-Wv9YAfv0

A working AED for "guided CPR" is pretty nice even when you're doing CPR, especially if you don't do CPR all that frequently, too.

If you have an AED, then you're not 'wasting time' getting it set up.

CPR won't restart the heart. An AED _might_. If the person has been down for several minutes, then a few rounds of CPR is a good thing, but if it's less that 2-3 minutes, go right to the AED, don't bother with compressions.

>CPR won't restart the heart. An AED _might_.

Do you have a source on this? We're talking about a healthy but traumatized heart, right? And are we talking about totally stopped, arrhythmia, or either?

I think by "restart", he meant the useful shorthand of "restore a useful rhythm, restart the heart as a pump instead of a tasty snack", and only in the case where the heart was in ventricular fibrillation or tachycardia. AEDs won't turn a "dead" heart into anything but slightly-cooked meat.

(I think you can use them in full manual mode with open chest and electrodes to treat a few more weird rhythms, along with cardiac massage (open-chest or regular CPR), but probably not happening on a paramedic call-out, more likely in a hospital setting. Normally you use CPR + drugs and then try the AED again. I'm not really sure of the details of the limits of dealing with asystole in a hospital setting, but I suspect in an OR they have some extra options vs. other places.)

You can _try_ using a defibrillator to transcutaneously pace an asystolic heart, but I've never seen that work.

I wonder if the next step would be being able to deliver drugs (atropine?) in a more targeted way (maybe tiny doses highly localized and recurring? I'm not sure exactly how it works) along with electrical or manual stimulation.

I guess another option might be a rapid way to put someone on heart/lung bypass, either in the field or at least in the ER, rather than only in the OR. Or rapid chilling, or both. I suppose if we either had long-term useful artificial hearts, or a more efficient/effective organ transplant regime, this might be more of an issue.

Atropine is mostly deprecated in cardiac arrest scenarios nowadays. It's still in-protocol for brady PEAs, but that's about it.

Rapid cooling is becoming very widespread in post-ROSC situations (we're spec'ing a chiller box for saline in our next rigs for that very reason), but if they're still dead, cooling them isn't likely to do much for them.

It would be really interesting to see cooling applied to dive medicine (I dive, and a friend of mine is a Canadian Forces MD who did a hyperbaric/dive med fellowship at Duke, so I read some papers on this stuff more than I would otherwise). Also seems like it could be really useful for flight medicine/extended distance transport post ROSC/etc.

We're talking about a heart that has been sent into either a pulse less ventricular tachycardia, or ventricular fibrillation, due to the timing of the electric shock (generally during the S-T interval).

By 'stopped' I mean 'stopped being effective'. If the heart has truly stopped (asystole), then by all means, pump on the chest.

Clarification is great, but what I really want is a source saying that an AED can help a healthy heart but CPR can't. I've heard somewhat similar things but I've seen little hard data and none of it was related to healthy hearts.

It's simply a matter of what each thing is designed to do.

If a heart has stopped completely (asystole or 'flatline'), then an AED is useless. You can try CPR and epinephrine, and in the best case scenario, you might get the heart into a condition where you can use the defibrillator.

A defibrillator is useful when the heart is beating in a chaotic fashion (or _way_ too fast). The electrical shock it delivers completely stops the heart, in the hopes that the heart's internal pacemaker can take over again.

CPR can't 'reset' the heart, all it can do it help slow down the dying process until you can get a defibrillator in use. Without the defibrillator, the heart will progress into a state where even the defibrillator won't be useful.

Here's the basic protocol: 1) If it's a child, do two minutes of CPR before using the AED (the most common cause of cardiac arrest in kids is respiratory arrest, so ventilating them is sometime all they need)

2) If it's an adult, and they've been down for more than a few minutes, do 2 minutes of CPR to 'prime' the heart to make it more 'shockable'

3) If it's an adult, and you just witnessed the arrest, use the AED straight away. Their heart is likely still oxygenated enough to restart easily. If they're not breathing, be sure to fix that...

http://www.heart.org/acls

In fact, an AED does not restart the heart. It's used in the case of cardiac arrhythmia. CPR is the proper protocol for a flat-lined patient.

http://en.wikipedia.org/wiki/Automated_external_defibrillato...

Except you cannot know if the patient is flat-lined or has arrhythmia. The AED performs an ECG and delivers a shock only if appropriate; if you have one available, you should always use it (which does not exclude CPR in the meantime).

Hence the 'might'. An AED may be able to restart a heart in ventricular fibrillation or ventricular tachycardia (I suppose we can quibble over what 'restart' means).

CPR alone never restarts a heart (ok... not 'never', but it's uncommon enough (in adults) that it's not worth fighting over).

In most cases you are correct, an exception is a lightning strike. Random Google coughed up this result "CPR usually has a success rate of 10% or less. In cases of lightning injury, CPR can have success rates of up to 90%. As such, normal rules of triage do not apply. If you find someone without a pulse or respirations after a lightning strike, begin CPR immediately." [1] [1]http://www.wildernessutah.com/learn/lightning.html

Or go back out in the storm and get hit again, that should do it, right? :-)

>Don't assume you're safe because you're not near a high point

Yet again human intuition proves counter-intuitive. It's easier for us to visualize that being at a high point is more dangerous than a lower place. If there were a method to use FFT and convert land from a height map to the resistance/conductivity domain, I'm sure there will be very very surprising results.

It has nothing to do with intuition, just with over-simplification. It is true that high points tend to attract lightning and that this can make you safe. The effect just isn't as strong as most people think.

Basically, the "leader" that establishes the path through which the main discharge will happen moves randomly downwards, but will be strongly attracted towards grounded objects that it comes close enough to - and "close enough" is only about 50 meters. So if there is a high point within a sphere of 50m radius centered 50m above your head, you're indeed almost completely safe (or at least you won't be hit directly - what hit Marlin was apparently a part of the charge that was moving through his house.

Another note is that the stepped leader that comes down meets another coming up from the ground. The one which reaches the one from the cloud creates the main channel, no matter where it is coming up from.

I grew up in an area that frequently had thunderstorms. I witnessed many strikes in my yard, including my house while I was in it, and investigated many in my neighborhood. Much of what the OP said was bullshit. If it were true, the lightning rods that attracted and diverted many strikes wouldn't need to be place high.

The strikes always hit taller object like houses and trees and I never ever saw a strike or evidence of one in the middle of a field.

Please don't generalize your experience across the entirety of all possible occurences.

1. http://www.youtube.com/watch?v=oqzjk1kp5Ug - Notice in the shot how the lightning hits a small, low-in-the-water boat.

2. http://www.youtube.com/watch?v=keVm06H26ik - In Boulder, with the mountains right next door, lightning strikes twice in the city proper, around 1,000 feet lower in elevation.

3. http://www.youtube.com/watch?v=YKw9kpD0rNc - Lightning strikes the water, less than a hundred feet away, instead of the palm trees the photographer is at.

My point was that assuming lightning will strike the highest point is patently false; it doesn't meant that a valley isn't any safer than a mountain - just don't assume that being in a valley protects you.

This is also an excellent clip showing stepped leaders in extremely slow-motion (the electrical leaders that lead to lightning strikes): http://www.youtube.com/watch?v=RLWIBrweSU8

HN is truly amazing. It seems I had a dangerously nonchalant view of lightning in the area I live. I now consider myself well versed on its hidden dangers.

"You will almost never get warning before lightning strikes."

Somehow animals can sense it. I've seen animals flee seconds before lightning struck.

Animals may indeed be more sensitive, but I've also seen animals not sense it at all prior.

I think it is hit-or-miss (pun intended) in the end, but it would be interesting to see if anyone has done more in-depth research on it.

This is great advice. I had a very close call last year, and have made it a point to ensure that it never happens again.

My Dad and I were on a fishing trip in Michigan and floating down the river with a guide in a long, canoe-like river boat. A storm came down the river from behind us pretty soon after we put the boat in. The guide decided to pull the boat to the side of the river under some overhanging tree branches. It didn't appear to be that big of a storm when we had looked at the radar earlier, and it was moving fast, so we weren't all that worried.

At the time I wasn't sure if it we had made the best decision, but there weren't any immediately better alternatives. As the rain got heavier, and the storm got closer, we just waited. I was in the bow of the boat, and the current kept swinging me out from under the branches into the main current. Every few minutes I'd pull on the branches to give myself better cover from the rain.

Eventually it really started pouring, and then hailing. The storm was right overhead, so we hunkered down. All in an instant I felt something weird come over my body (not hair standing up, just something different), I saw a bright orange flash, I screamed like a little girl, I ducked and covered my head while hearing an extremely loud crack.

After maybe a second I popped up and said to my Dad and the guide "Are you okay?" I was a bit surprised to hear myself after having been so close to such a loud sound. They didn't respond. I repeated myself, and they both said, "Did you see that?" I said, "Did you hear me scream." They both said that they hadn't.

My dad says that he saw a hole in the water where the lightning struck, just two or three feet from where I was sitting in the boat. The bow of the boat had been in that spot minutes before, but I had pulled it back under the trees. I wasn't holding my fishing (lightning?) rod, but I easily could have been.

I felt sick. We could smell the ozone.

I don't think it was a particularly big/strong bolt, but it was big enough.

There was a guy across the river who had also pulled off to take cover. He was freaked out because he was so close to where the bolt struck. Then he realized how close we were.

After the storm passed, we called it a day (didn't even catch a fish), and paddled back to the lodge (which was about 20 minutes downstream).

About a month and a half later, we were with the same guide in the same boat, but on a different stretch of river. We thought we were clear from the storm that we saw on the radar, but this massive cell ended up right on top of us. We were right on its edge, so the lightning would get closer and then farther away and then closer again. We were smart enough to get out of the boat this time, but ended up crouching in the woods for nearly three hours hoping the storm would pass.

It was pretty terrifying. I'm definitely scarred by my experience. I can't enjoy thunderstorms the way I used to. When I see the orange flash or hear the loud crack of a close strike, I'm taken back to last May and I feel kind of sick. I'm really lucky that is the only lasting effect from a few poor decisions.

------

What I've learned:

1. Don't put yourself in a bad situation. Watch the radar, and have a plan for if/when a storm is getting close.

2. Don't be afraid to travel to a safer place. There is a time to hunker down, but it's not until you really have no other options.

3. Most people don't know much about lightning safety.

4. Your friends will make fun of you for taking electrical storms seriously. Getting some crap from your friends is better than getting hit by lightning.

5. You are never totally safe. If a guy in his office chair can get hit, then you can get hit almost anywhere. Still, there is almost always a safer place to be. Get there if you have time.

6. Small storms can be more dangerous that big storms. If you hear thunder, take it seriously.

7. Take a few minutes to read up on lightning safety (http://www.lightningsafety.noaa.gov). It will probably be useful at some point in your life, and what you think you know is probably not 100% right.

8. Most lightning safety tips seem overly cautious. They are, but it's something uncommon enough and dangerous enough that being overly cautious is worth the aggravation.

Yeah, that is about what my closest call was like.

What I've always found interesting is the lack of sound in about half the cases I've learned of. In my own closest call, which was 23" away from my left arm (streetlight), I remember hearing a buzzzzzz-bzzt and then wondering why I was in the air falling toward the mud.

About half a second later a giant crack happened, from a stringer off the main bolt.

In the first video I referenced, it wasn't even that loud! The whole sound/proximity question still fascinates me.

As for your experience, I've been a fisherman for most of my life. Thankfully, I've not had really bad experiences with lightning while fishing, but yours is a great lesson.

And one thing to note is that a fishing rod is one /hell/ of a lightning attractor. If you've got carbon fiber near you, get away from it rapidly.

> Small storms can be more dangerous that big storms. If you hear thunder, take it seriously.

This is extremely important as well, because we'll often disregard a towering cumulous cloud with the classic "aw, that ain't a storm!" That can change in seconds, because powerful updrafts can move upwards of 100mph. Being outside in a highly unstable weather environment is inherently dangerous.

Yeah, I was pretty certain right after it happened that I had sustained hearing damage, but after hearing myself speak I was happy to realize that I hadn't.

I've had quite a few thunderstorms come up on me while I was fishing. The one that almost got me was one of the less scary ones in terms of my feeling of safety. I think I'm now destined for a life where every plane overhead or truck driving by immediately makes me think thunder.

> Stay safe.

HOW? The lightning entered his window...!

Technically lightning would have left via the window, it goes from the ground up and just looks the other way around.