Help solve a bar bet around this scene from 'Gone Girl', please!
April 3, 2018 6:01 AM   Subscribe

There is a scene where we see Amy use a winged infusion set nicked from her doctor's office to draw a quantity of her own blood. Would it have been possible for her to die accidentally by exsanguination via this method, or would the blood flow into the needle slow down before it reached a point to endanger health?

(spoilers if you've not seen the film/read the book)

This refers to the montage where we see how Amy staged her disappearance, by drawing blood which she then spreads about and messily cleans up, to imply she had suffered injury at someone else's hands. At one point she is shown to be sat on the floor reading as she collects a sufficient quantity of blood into a container.

I commented on how this method was risky, as she could easily become lightheaded/lose consciousness and bleed out. My companion felt this wouldn't be possible, as it was blood drawn via puncture into an open container at the usual forearm/elbow location, and that it wasn't possible to lose enough blood under these circumstances. (Relevant scene -- also, CinemaSins apparently is on my side.)

This got surprisingly contentious, albeit in a friendly manner. Neither of us is especially well-versed in medical subjects, and our collective experience in related situations doesn't go much beyond blood donation. A few concessions were made along the way, e.g. while just yanking out the needle once lightheadedness comes on is quite easy, the character is shown as being obsessive over details and could potentially push it a bit too far to get the 'right' amount, then pass out; pressure at that site might not be sufficient to bleed out, but a similar venipuncture in a larger/more central artery could have had that result; without the vacuum pressure of a bag/test tube bleeding wouldn't be so swift and would taper off on its own.

There were several quibbles over the validity of the character's plan, but for some reason this is the one we really got stuck on. As the discussion wore on, we realised we couldn't answer this question under our own steam, and as Googling only turned up ancillary data, I bring the question here: any nurse practitioners/health professionals/other medically-trained types who have studied the subject and can put this argument to rest? Shots of single malt ride on the answer ...
posted by myotahapea to Health & Fitness (4 answers total) 1 user marked this as a favorite
Best answer: Disclaimer: Work in healthcare, not an expert at staging own death.

I would be very surprised if someone could actually 'bleed to death' out a single 21 or 23 gauge (typical size) winged infusion set. They could certainly lose a fair bit of blood, but as their blood pressure dropped from the blood loss, the odds that the set would become clotted off and cease to bleed significantly is pretty good. If they placed several large (say 14 gauge) short IV catheters in larger vessels (which is more similar to a donating blood setup), then yes, it's possible to loose enough volume for it to be fatal. But given the regularity with which IV catheters (especially small, winged ones) 'clot off' even with non clotting fluids ostensibly running in, I think the likelihood of a winged infusion set being fatal is pretty low. When blood is 'drawn' at a lab, it is into a vacumn container as well (although this wasn't the case in the clip) which helps the set stay patent. As well, once gravity is no longer on the flowing side (when she passes out flat) that will likely help slow the flow as well.

So, I'm going to say, not impossible, but unlikely to be fatal in this setup.
posted by Northbysomewhatcrazy at 9:10 AM on April 3, 2018 [3 favorites]

I have a sibling who works with blood safety stuff and I ran this by her. She concurs with Northbysomewhatcrazy.
given i have not seen the movie: it is exceedingly unlikely you would die unless you had a clotting disorder. assuming the puncture is in the vein and not an artery, there is not enough pressure. blood would eventually clot in the tube or the tube itself would collapse due to vacuum pressure. so while theoretically possible, and has actually been tried for suicide, it is unlikely to result in death.
Because honestly, it takes a lot of blood loss before you're at the lightheaded stage for most people and even then, unless you had a suicide wish, it's pretty easy to stop the bleeding from a low-grade stick like this. Many people get queasy etc. because of personal/emotional feelings about blood and medical stuff, but absent this sort of thing or really messy syncope she would not die. And saying "Oh but what if it were an artery" is sort of moving the goalposts.
posted by jessamyn at 9:22 AM on April 3, 2018

Incidentally, this was the only part of the book Fincher demanded be changed for the movie, because in the book she just cuts her own jugular and controls the bleed. From an interview with Gillian Flynn:

Q: Why did you change some of Amy’s methods, then? Such as the way she collects her own blood?
A: That was David. David just didn’t buy it. He was like, “She’s too careful.” And of course, being Mr. Smarty Pants, he was like, “Have you ever actually cut a jugular? Do you know anything about anatomy? You could very easily hurt yourself! It’s got to be more precise.” So he didn’t buy it.

Q: But that’s the kind of thing I would think David Fincher would like …
A: Would like to see? Yeah, I agree. I was kind of surprised, too. David is very visual, but he’s also very, very much about the truth. Could this happen in the real world? . . . I always found it interesting how much of a stickler he is about, “But would that happen? Has that really happened?” He really pushes you to road-test it. I could not sell on him on Amy’s blood. He was like, “No. 1, you could pass out. No. 2, it’s messy, and if she’s dripping somewhere else, she’s going to leave behind a trace. She’s got to do it a surgical way.”
posted by a fiendish thingy at 12:14 PM on April 3, 2018

It is possible to do this with a dialysis catheter (and people have), but dialysis catheters are the size of a drinking straw, and lead directly into the central veins/right atrium of the heart. A normal phlebotomy set is smaller than a phone charging cable, and goes into a smal vein which will usually collapse when it’s empty.

When you open a dialysis catheter, the blood pours out like you’ve opened a tap. When you open a phlebotomy set, unless you apply negative pressure (from a vacutainer or syringe), the capillary pressure in the tube is such that the blood drips out extremely slowly (like a very slow dripping tap), or stops altogether. You also won’t get any blood out of a peripheral vein unless you increase the pressure in the vein by applying a tourniquet. When you take it off again, the blood stops. You’d have to be very determined to exanguinate from a butterfly set.
posted by tinkletown at 12:15 PM on April 3, 2018 [1 favorite]

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