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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 pe

by pge 13y ago

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.

kposehn 13y ago
Glad you were unscathed (assuming). Excellent point about CPR and blindness as well.
- rdl 13y ago
  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.)
  - MartinCron 13y ago
    The idea of a sub $500 AED from eBay makes me feel very nervous.
    - shabble 13y ago
      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 https://www.youtube.com/watch?v=pn-Wv9YAfv0
      - rdl 13y ago
        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.
      - JshWright 13y ago
        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.
        Dylan16807 13y ago
        >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?
        rdl 13y ago
        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.)
  - paul_f 13y ago
    Or go back out in the storm and get hit again, that should do it, right? :-)
sigkill 13y ago
>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.
- brazzy 13y ago
  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.
  - kposehn 13y ago
    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.
  - slacka 13y ago
    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.
    - kposehn 13y ago

by pge 13y ago

kposehn 13y ago

Glad you were unscathed (assuming). Excellent point about CPR and blindness as well.

rdl 13y ago
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.)
- MartinCron 13y ago
  The idea of a sub $500 AED from eBay makes me feel very nervous.
  - shabble 13y ago
    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 https://www.youtube.com/watch?v=pn-Wv9YAfv0
    - rdl 13y ago
      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.
    - JshWright 13y ago
      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.
      - Dylan16807 13y ago
        >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?
        rdl 13y ago
        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.)
- paul_f 13y ago
  Or go back out in the storm and get hit again, that should do it, right? :-)

sigkill 13y ago

>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.

brazzy 13y ago
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.
- kposehn 13y ago
  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.
- slacka 13y ago
  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.
  - kposehn 13y ago