Anonymous asked:

Thank you so much for running this blog! I didn't see a search function, but I did my best to go through your drowning tag. What I can't seem to find anywhere (including google) is how much liquid it takes for a person to drown. The scenario is captured MC can control water but is new to it, and there isn't that much around so the plan is to have the villain breathe in the humidity but not let him breathe it out. Just trying to figure out how long it would take.

scriptmedic answered:

Hey there nonny! First, all Tumblr-native blogs have a search function; on ScriptMedic it’s at the top left of the page (browser) or the top right of the page (app). 

However, I’ve never answered an ask quite like this one, which makes it really exciting! 

The volume it takes someone to drown can be deceptive, because something called a dry drowning is possible! That’s an event where the character is going to drown, and their body actually snaps shut the larynx – the voicebox. Laryngospasm keeps water from getting in, but it also keeps air from getting in or out, and they can suffocate from this even if they’re out of the water already. 

There’s also secondary drowning, where a character can survive a near-drowning for a few hours, then drown in their own fluids. What happens is that the lungs get irritated by the water that’s in them and the capillaries dilate, and the lungs flood themselves with fluid. It’s called Acute Respiratory Distress Syndrome, or ARDS. 

However, you talked about using humidity to drown a character, and I think that’s a really interesting idea. Unfortunately, I’m not entirely certain it would work. 

The human body really wants the air it breathes to be humid. It’s very important, because the inner lining of the airways needs to be kept moist. Part of why we breathe in through our noses is that the turbinates not only filter the air, but they warm and humidify it, too. One of the biggest components to being a respiratory therapist – the people in hospitals who manage ventilators – is that because we bypass this vital system when we intubate somebody, they actually have to work very hard to make sure that the air that enters an intubated character’s lungs is warm and humid to the correct level. 

But I don’t think you can drown anyone with humidity. 

Here’s why. Air will only support so much water dissolved into it; water is heavy, and air is a gas, and there’s a saturation point at which the humidity simply falls out of the air as water. I simply don’t think even 100% humidity is enough water to drown someone. 

As to the actual volume of water needed to directly drown the lungs – if, magically, water came into the airway below the larynx and started to fill it? There are a few numbers this could be, but I can’t put 100% truth to any of them. 

Humans exchange gas along about 6 mL/kg of space within the alveoli, or about 480mL in an 80kg adult (176lbs). There’s also what’s known as anatomical dead space, which is basically the amount of a breath where no gas exchange occurs, and that’s about 2mL/kg, or 160mL in an 80kg adult. Total volume is something like 640mL. 

But I would wager it would take only half of this to actually cause enough drowning to significantly impair gas exchange to the point of death, immediate or eventual. That’s about 320mL, or about 11 US fluid ounces. 

Basically, a can of soda will kill this character, but it can’t simply come in by inhaling steam, mist, or humidity. 

Best of luck, nonny! 

xoxo, Aunt Scripty

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