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Show HN: Spot the Drowning Child

spotthedrowningchild.com

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Re: Show HN: Spot the Drowning Child

#361

Post by corin_ »

irishcoffee wrote: post #271
tomjen3 wrote: post #209

Earlier quoted context omitted.

That would make for a pretty fucking boring pool, honestly. No flotation devices would mean that all I could do as a kid would be to stand around on my tiptoes.

I was tempted to go on a diatribe about your comment, but I'll leave it at this: my job was to guard lives, not provide entertainment. Nobody died, which gave every person I guarded the opportunity to pursue an anti-boring life in whatever way they see fit.

I'm not saying you drew the line in the wrong place, as I know nothing about the subject, but surely you could also close the pool so nobody can use it for the same reason of "saving lives, not providing entertainment"

Re: Show HN: Spot the Drowning Child

#362

Post by janekm »

trhway wrote: post #198
janekm wrote: post #185

Earlier quoted context omitted.

Costwise, I think that would be in the ball-park, if we can figure out what to monitor, and how, it could most likely be manufactured for I do work in this field (wireless vital signs monitoring) and unfortunately I don't know of any current technology that I would trust to monitor heart rate on a swimmer other than perhaps a chest strap (but not as a safety device either). For a point of reference, the Apple watch f…

just googled more :) - https://en.wikipedia.org/wiki/Pulse_oximetry - an adapted for waterpool conditions earlobe oximeter is probably what is needed here (with probably a transmitter/amplifier with battery in the wristband). But currently it is in the $100+ territory.

It's not that simple unfortunately. One concern I have is that the oscillatory motion of the drowning response is well within the range of cardiac rates (1-3Hz from the video). Pulse oximetry data is quite noisy and is especially affected by motion affecting the sensing apparatus. Pulse Oximeters employ algorithms to attempt to reject noise (including noise from motion). Unfortunately these algorithms tend to depend on the cyclical nature of the heartbeat signal (using FFT or auto-correlation to latch onto the heartbeat signal, for example). The presence of an oscillatory confounding signal (noise induced from the motion of the drowning subject) would significantly reduce the reliability of these algorithms.

A device for alerting for a drowning subject would be classified as a medical device (in Europe most likely class IIb as it is measuring a vital function in a life support scenario) as the malfunction of the device could fail to prevent the saving of a life. The burden of certification of such a device is understandably high, and one would have to be able to demonstrate that the device can accurately and reliably measure in its intended use and show that any risk that it doesn't has been adequately reduced (I'm simplifying greatly).

Unfortunately it's basically impossible to test, after all how would one get ethical approval for exposing subjects to conditions of near-drowning, so one would be dependent on placing prototype devices on swimmers and catching episodes of near-drowning by chance. It would take a considerable length of time to gather sufficient data to confirm the reliability of the device under such conditions, obviously...

(and no, I would not consider it appropriate to test the device under general swimming conditions as these would not adequately predict performance under drowning conditions).

In terms of cost, an earlobe pulse oximeter doesn't have to be more expensive than a fingertip one (aside from some miniaturisation costs perhaps) but part of the costs of these devices is due to patent issues: http://www.law360.com/articles/106524/philips-accuses-pulse-...

Re: Show HN: Spot the Drowning Child

#363

Post by lukaslalinsky »

irishcoffee wrote: post #30

I would like to point out that any flotation device in a pool besides a life jacket is just asking for problems. I life-guarded for almost 10 years, the only way I would ever let anything that supported a human floating __besides__ an approved life jacket was if the pool was almost empty (such that the one person got my undivided attention) and if I knew the child to already be a strong swimmer. I highly encourage ev…

As far as I see it, there are two use cases for a pool, swimming and fun. I'd agree with you if you were talking about a pool with swimming lanes. The point of the pool in the video on the website is to have fun. If you make it safe, you kill the fun.

Re: Show HN: Spot the Drowning Child

#365

Post by monk_e_boy »

parfe wrote: post #123
monk_e_boy wrote: post #26

Earlier quoted context omitted.

I was a lifeguard at a beach. I didn't have any dramatic rescues like the video, but you soon get a feeling of which kids are a little too adventurous and need keeping an eye on. Your brain soon kicks into holding your breath while watching kids swim, if one is splashing around while you start to feel uncomfortable it's time to wade in and drag them to the surface. Often for us it was the uneven sea bottom, someone t…

>hoik I learned a new word today. >2. To lift something up wildly.

I've never written that word down, had to just go phonetically

Re: Show HN: Spot the Drowning Child

#366

Post by Dylan16807 »

jacquesm wrote: post #346
Dylan16807 wrote: post #341

Earlier quoted context omitted.

Right, that forces you to reach two minutes, and also makes sure the bag will be removed promptly. As far as I can tell most of the danger comes from the possibility of having someone hold you still while you panic, and that is not what I generally consider deadly. Really not sure if I'm missing something...

> Right, that forces you to reach two minutes, and also makes sure the bag will be removed promptly. No, it does not make sure of that, besides it said 'a couple' and not 'two' (depending on the person two might very well be enough to harm them, but some might interpret 'a couple' as being even more than two). The person was suggested to be there to make sure you can't remove the bag yourself and by the time the bag…

>"Any activity that deprives the brain of oxygen has the potential to cause moderate to severe brain cell death leading to permanent loss of neurological function ranging from difficulty in concentration or loss of short term memory capacity through severe, lifelong mental disability to death."

That cites source 12, which doesn't seem to support the critical "any activity" part of the sentence, at least in terms of how long the oxygen deprivation lasts.

>95.7% of these deaths occurred while the youth was alone

Seems to support my skepticism for a strictly-timed co-operative activity.

I'm not even sure you'd end up in oxygen deprivation at all within a couple minutes when you start with a nice big breath.

I'm sorry you think my question is dumb. I was just hoping to learn something. At this point I'm feeling reasonably confident that I wasn't unaware of important information, and 'dying' was strong hyperbole. I'll note again that I don't support actually doing it.

Re: Show HN: Spot the Drowning Child

#367

Post by TeMPOraL »

sampo wrote: post #307
haddr wrote: post #275

Earlier quoted context omitted.

Once we did rafting and our monitor guy told us: when you fall into the water and find yourself under the boat, just don't panic. Don't try to move your head up but rather chose whatever direction and swim until you reach the either side. We thought it would never happen, but we ended up few times in the water just like just like that. And even though it's just a few seconds you are quite disoriented and at first tim…

Sounds like an easy thing to practice? Go to a pool with a boat, dive under the boat, and practice getting out. Like people who do kayaking practice how to get out when the kayak turns upside down.

I came to realize that a lot of things in life are easy when you practice beforehand. It's a good idea to identify things you don't expect how to handle and then go and learn to handle them. It's especially important to learn how to use the tools you may need in emergency so that they won't surprise you when you need to use them quickly. Otherwise having those tools only gives you false sense of confidence, which may be dangerous.

So for instance, I bought a fire extinguisher and used it up in some deserted bushes. It was a small expense, but now I'm fully aware how this particular type of extinguishers behave. Or when a friend wanted to buy mace (she was coming home late at night), we bought two and used up one for doing target practice, so that she's aware how the fluid stream behaves and how to aim it.

The biggest problem with this approach that I find is that there are so many things you could prepare yourself. Even if it usually would just take a few minutes and little to no expense, you can't train for things you don't realize exist as concepts or situations. For instance, thanks to this subthread it is the first time it occured to me that a situation like obstructed surface when diving in a pool can occur. I'm adding it to my mental list of things to prepare for when I get the opportunity.

Re: Show HN: Spot the Drowning Child

#368

Post by AmirS2 »

noja wrote: post #353
TheAnimus wrote: post #245

Earlier quoted context omitted.

I would have been a blue band in your system. My parents moved to Cornwall when I was child, surrounded on 3 sides by water, I gained my surf lifesaving certificate, I was a good swimmer. Almost two decades passes. I'm in Bali, on a deserted beach with my ex because we "don't want the average experience" or whatever. A small argument and I decide I want a swim. I walk out through the surf, my mind overcome with thoug…

Why did you swim against a rip current?

> normal to the rip tide

as an engineer, I assumed this ('normal') meant across/perpendicular/90 degrees to the rip tide, not against it ...

I believe 90 degrees to a rip tide is the correct thing to do ...

Re: Show HN: Spot the Drowning Child

#369

Post by chucksmash »

yellowapple wrote: post #317
jsprogrammer wrote: post #310

Earlier quoted context omitted.

A rectangular pool with a flat bottom (probably accounts for the majority of pool volume world-wide) would be pretty easy to have full camera coverage over with minimal image distortion. Each object could be easily tracked for time underwater, depth, etc. (and expanded to track fine motion as well) Objects that stay near the bottom are suspect. The system could alert lifeguards to the exact location of a victim. You…

Right, but my point is that we're not quite at the point where a computer can reasonably process that much visual input, determine whether or not something is exhibiting the signs of drowning, and alert a lifeguard with a minimum of errors. False positives will lead to personnel confusion, and false negatives will lead to dead swimmers. This isn't to mention that automation does encourage complacency. One of the prim…

> False positives will lead to personnel confusion

False positives can lead to death too. This article talks about alert fatigue that contributed to a fatal medication error at UCSF:

https://medium.com/backchannel/beware-of-the-robot-pharmacis...

I'd be wary of giving a lifeguard who might be straining to pay attention to n things an n+1th thing to pay attention to.

Re: Show HN: Spot the Drowning Child

#370

Post by frogpelt »

lukaslalinsky wrote: post #363
irishcoffee wrote: post #30

I would like to point out that any flotation device in a pool besides a life jacket is just asking for problems. I life-guarded for almost 10 years, the only way I would ever let anything that supported a human floating __besides__ an approved life jacket was if the pool was almost empty (such that the one person got my undivided attention) and if I knew the child to already be a strong swimmer. I highly encourage ev…

As far as I see it, there are two use cases for a pool, swimming and fun. I'd agree with you if you were talking about a pool with swimming lanes. The point of the pool in the video on the website is to have fun. If you make it safe, you kill the fun.

    > If you make it safe, you kill the fun.
It puts a damper on things when someone drowns too.
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