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0 pointsamelius6y ago0 comments

Isn't it possible to design the product such that its risks are greatly reduced? E.g. by limiting the amount of insulin it can deliver in a given timeframe?

0 comments

dekhn6y ago

This comment falls under the "why don't you just..." cluster. Even implementing a feature like that (assuming it made sense) carries risk (imagine if your limiter's sensor broke and it failed open).

Designing reliable systems is incredibly hard. It requires a ton of resources (money, lawyers, engineers) And experience and long time frames with relentless effort to document everything so that when somebody does die, you can root cause it and fix the problem without regressions.

I've been continuously impressed with what open source hackers have done with open biology projects, but that doesn't mean any of these products are reasonable replacements for the products that are used by tens to hundreds of millions of people.

jacquesm6y ago

> This comment falls under the "why don't you just..." cluster.

It does, but just this once it is spot on, the best pumps on the market do just that.

dekhn6y ago

yes, it's spot on, but only a tiny part of a much larger system. And even implementing that feature is devishly complicated. Hence my statement "why don't you just".

piersadrian6y ago

Agreed - open body-hacking projects are amazing feats of community and perseverance, but the systemic cost and access issues that plague high-end medicine will persist until they’re addressed systemically.

liamzebedee6y ago

A bit of elaboration on the risks you could encounter here:

- CGM sensors can be faulty, depending on the rate of change of glucose (they’re actually not measuring blood directly, but interstitial fluids, which are generally lagging by about 15mins and can be inaccurate with large swings)

- battery dying out isn’t so bad, since the pump will just default back to its previous basal delivery settings - there are safety maximums on insulin delivery, which prevent among other things, your typical overflow/precision errors

- maximums over time though is a more complex issue, something I haven’t yet dug into

jacquesm6y ago

And then there are... pump actuator failure, syringe seal failure (on syringe based pumps), valve failure (on valve based pumps), user error (on all systems), reservoir running out, occlusion, air bubbles and a thousand other things that can go wrong. This is not exactly easy material in the best of cases and most sensor packages do not have redundancy and will at best address only a small fraction of all possible failure modes.

sgift6y ago

Delivering something fast, accurate and under wildly changing conditions in the human body is far more complicated than most people assume.

I still remember when I had to be hooked up to an infusion pump for many hours at a time. In theory this was all pretty simple - I had a port (a permanent link to my blood system), the machine was hooked to the port, the machine was configured to deliver x ml per hour. Easy, right? Well ... moving my arm had a non-zero chance to trigger the alarm (alarm means "the machine has a problem to deliver the configured amount", please do something), moving in the bed had a higher chance, walking over the hospital corridor I could almost guarantee that at some point in a single walk (i.e. one length of the corridor) it would freak out and again start the alarm. And that's for a far easier system in very easy conditions. An insulin pump has to change what it delivers all the time and it has to work always. Sport, work, driving, running, ...

vineyardmike6y ago

Adding to what others said, too little insulin can be dangerous, so if users don't know/notice that it stopped delivering more insulin, they might not manually add the requisite amounts.

Forgetting to take medication is dangerous, overdosing medication is dangerous. It is just not that easy to design a system like this.

j / k navigate · click thread line to collapse

0 comments

dekhn6y ago

This comment falls under the "why don't you just..." cluster. Even implementing a feature like that (assuming it made sense) carries risk (imagine if your limiter's sensor broke and it failed open).

jacquesm6y ago

> This comment falls under the "why don't you just..." cluster.

It does, but just this once it is spot on, the best pumps on the market do just that.

dekhn6y ago

yes, it's spot on, but only a tiny part of a much larger system. And even implementing that feature is devishly complicated. Hence my statement "why don't you just".

piersadrian6y ago

liamzebedee6y ago

A bit of elaboration on the risks you could encounter here:

- maximums over time though is a more complex issue, something I haven’t yet dug into

jacquesm6y ago

sgift6y ago

Delivering something fast, accurate and under wildly changing conditions in the human body is far more complicated than most people assume.

vineyardmike6y ago

Adding to what others said, too little insulin can be dangerous, so if users don't know/notice that it stopped delivering more insulin, they might not manually add the requisite amounts.

Forgetting to take medication is dangerous, overdosing medication is dangerous. It is just not that easy to design a system like this.

j / k navigate · click thread line to collapse