[HN Gopher] Alarms in medical equipment
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Alarms in medical equipment
Author : gaudat
Score : 92 points
Date : 2024-06-07 18:45 UTC (4 hours ago)
(HTM) web link (th.id.au)
(TXT) w3m dump (th.id.au)
| odiroot wrote:
| I was looking for some good notification sounds for my ESP Home's
| buzzer. These are a great inspiration.
| bouvin wrote:
| Fascinating. Interesting to hear the differentiation in severity
| in the same class of error.
|
| Though a bit disappointing that there is no machine that goes
| PING! [1]
|
| [1] https://youtu.be/VQPIdZvoV4g?si=Ov4AuyKgeKtmYmz9
| LorenPechtel wrote:
| And how about the fact that there are simply too many of them!
|
| I was once in the recovery room with my wife. For some reason the
| sensor was having a very hard time reading her pulse. The normal
| bips would frequently fail. Too many failures in a row and the
| alarm would start it's EEEEEE scream we've all seen from
| Hollywood. It would shut up as soon as it managed to pick up a
| beat.
|
| Hers was definitely not the only one in the room occasionally
| screaming. The nurses were completely ignoring it. Quite
| understandably so as it was obviously doing false alarms. But in
| a flood of false alarms like that are the real ones going to be
| noticed??
| jandrese wrote:
| False positives are definitely a problem. When you read
| industrial accident reports one extremely common theme is some
| sensor that was notifying the controller of the problem, but
| that sensor had a history of false positives so it was
| disregarded. Companies that don't take false positives
| seriously are inherently dangerous.
| teeray wrote:
| Many of those companies fall into the trap of "well, we'd
| rather a noisy alarm that catches the problem than a silent
| one that doesn't." Both are problems. The former just makes
| management feel like a problem would be caught be the on-
| call.
| throwaway173738 wrote:
| The ventilator company I worked for tried very hard to
| avoid false positives because we were very concerned about
| alarm fatigue. We also tried to ride the line on false
| negatives. It's really hard.
|
| Sometimes the alarm limits are set incorrectly by the RT or
| aren't forgiving enough to allow some motion. When you see
| an entire ward of nurses totally ignoring alarms it's a
| management failure. Either there aren't enough nurses
| available to manage the issue or there aren't enough
| technicians to properly configure the equipment for each
| patient. If someone dies because of that then it's
| ultimately the hospital's fault.
| kelnos wrote:
| > _Companies that don 't take false positives seriously are
| inherently dangerous._
|
| Alarms with incessant false positives are inherently
| dangerous. Sure, there's some threshold of false positives,
| under which we should still expect people to investigate all
| alarms. But above that threshold, how can we continue to
| blame the people involved? The hardware is at fault.
| pjerem wrote:
| I think GP was talking about the people who don't try to
| reduce false positives (by actively searching for solutions
| to reduce them), not the ones ignoring them because they
| are used to.
| kmoser wrote:
| It's hard to solve the problem of false positives when the
| decision to sound an alarm is reliant on a single sensor that
| may start to become detached (e.g. glue/tape failure). If you
| think the solution is multiple sensors, well, what happens
| when one sensor indicates an alarm condition and the other
| doesn't? Now you have _another_ potential false positive. Not
| to mention it 's untenable to connect _twice_ as many leads
| to a patient.
| bee_rider wrote:
| If they'd use three sensors, they could vote. If one sensor
| often votes differently from the other two, it could be
| marked as defective and replaced or re-seated.
|
| Three times as many leads would be pretty annoying, though.
| lostlogin wrote:
| You've hit the nail on the head. It's often tedious
| getting one to work.
| ler_ wrote:
| Knowing how to trend the patient's health is probably more
| useful than relying on all the alarms. People hardly
| deteriorate from one second to the next if you know what to
| expect from their baseline. At least that's what I did when
| working as a nurse. However, I never worked in some place like
| the ICU, so the approach might be different in that case.
| btach wrote:
| Anecdote: At an ED I used to work at, our cardiac monitors got
| "upgraded" to another manufacturer. Silencing false alarms was
| a black hole of a game of whack-a-mole. You could never silence
| them all, another would just pop up to spite you. Anyway, one
| night, it was continuing to alarm and being ignored (with a
| glance occasionally to make sure). Except somebody was in
| v-tach and the person who noticed was a medic bringing a
| patient in. Thank goodness they noticed amid the noise! (We had
| as good of outcome as could be expected with that patient, and
| they went to the cath lab and lived).
| dmurray wrote:
| What would have happened if the medic didn't notice and the
| patient died? Would you have got the blame for ignoring it,
| or management for creating a situation where you had no
| choice but to ignore some alarms because of false positives,
| or the manufacturer, or would it have been swept under the
| rug as "the patient was having heart failure and
| unfortunately even our state-of-the-art medical care couldn't
| save him"?
|
| All of those sound superficially plausible to me, although I
| have my ideas on which are more likely... Would you even do
| an, um, incident post mortem for something like that or would
| it just be a statistic?
| UniverseHacker wrote:
| Hospitals have a sort of manic "New York Stock Exchange" energy
| and environment to them... The entire environment of a modern
| hospital seems brutally incompatible with the type of peaceful
| relaxing environment you'd want to reduce stress and improve
| patient outcomes. Bright lights, constant noise, loud
| electronics, preventing patients from sleeping based on
| whatever schedule is convenient to medical staff, etc.
|
| I think they could substantially improve patient outcomes by
| taking some tips from the best modern birthing centers, and
| make a quiet, relaxing, dimly lit, and peaceful environment at
| hospitals. I'd also say add some plants, natural (wood)
| surfaces and natural light, but realize that might make it hard
| to keep things sterile and private. It would make sense to
| create a rough schedule for each patient also with a consistent
| "left alone unless there is an emergency" time for sleep, etc.
|
| I would imagine a calm and quiet physical environment would
| also reduce stress, fatigue, and improve performance of the
| medical staff themselves.
| tux3 wrote:
| Trying to figure out which melody was which in an emergency
| doesn't seem like the most human-friendly.
|
| Contrast with the GPWS warnings in aviation, which tells you what
| the problem is (TERRAIN TERRAIN) and what to do (PULL UP) in a
| progressively more alarmed voice as things get worse.
|
| (Well.. Sometimes you hear of some particularly bright
| individuals who think the bank angle warning is a _checklist
| item_ , but it's generally hard to get these wrong, compared to
| many other beeping warnings)
| sebmellen wrote:
| GPWS warnings should be the gold standard for any sort of
| urgent audio alarm.
|
| Examples: https://www.youtube.com/watch?v=W5Z-d1Zx02o
| imglorp wrote:
| At :42 I think the buzzing sound is the "stick shaker" stall
| warning. It literally shakes the pilot's control yoke. So not
| only is it an alarm, it's also reminding the pilot of the
| correction needed: to push the control forward.
| Lammy wrote:
| Making this my PagerDuty alert sound
| https://youtu.be/fbfVGIBcD8c?t=77
| flemhans wrote:
| I used to have pull up as my ringtone, freaked my uncle out
| (who's a commercial pilot) when he was over for dinners. Or
| at least he pretended to be :P
| masto wrote:
| Now I have this.
|
| https://looptube.io/?videoId=W5Z-d1Zx02o&start=77.1286764705.
| ..
| yread wrote:
| They also have their share of cavalry charges and buzzers. Plus
| the plane sometimes calls you a retard
| kmoser wrote:
| At least chimes are language-agnostic. Verbal warnings like
| "pull up" are only good if you have a reasonable grasp of
| English.
| graypegg wrote:
| At the very end, there's some examples of more literal
| sounds. It says there hasn't been a study, but I would bet
| they're a lot more clear with out having to resort of the
| aviation standard of "just learn basic english".
|
| _buh-bump_ is cardiac stuff. _wiSShhh... wooosSH_ is
| respiratory stuff.
|
| Only thing is, I bet you can hear sounds similar to those in
| a hospital. The "beep beep" they put over it might not be
| enough. Still a really interesting research topic!
| turrican wrote:
| True, but professional pilots from all countries are expected
| to be fluent in Aviation English.
| https://en.wikipedia.org/wiki/Aviation_English
| flemhans wrote:
| Another good thing is that they allow for talking over them
| better. The same way you may sing along to an instrumental-
| only music track using whichever lyrics you prefer.
| graypegg wrote:
| I wonder how much information any 1 medical device with an
| alert knows though. GPWS has the benefit of being part of 1
| system, where (I think, no experience here) hospitals seem to
| treat equipment as singular items that do 1 thing or are meant
| for a specific area of responsibility in an operation. Like a
| vitals monitor might not know what the drug pump is doing.
|
| I could imagine ventilation?
| arrhyth-*C-chord*-ARRHYTHMIA! CHECK PUMP! HEART RATE!
|
| coming from different devices to be pretty distracting.
|
| I think GPWS can set windows of cases where an alert is given.
| Like, a terrain warning isn't much help when landing. Maybe
| there's something like that already for medicine, but a device
| who's job is to consume information from other devices, and
| only provide alerts based on rules the staff can configure
| before an operation, could be a thing that's useful.
| HeyLaughingBoy wrote:
| That's really the problem many here are describing. 60601
| mandates what alarms shall be active, but it spans a single
| device. If you have, e.g., 10 ventilators in a room that are
| alarming, you can't silence them all with a single button
| press.
| graypegg wrote:
| I can kind of understand why it ended up that way. There's
| some benefit to just assuming, nothing works together. It's
| at least a consistent state of affairs. You can just wheel
| in any heart rate monitor, and you only need to understand
| that heart rate monitor.
|
| But it seems like a space that's really ripe for improving.
| We have very reliable simple protocols you could hook these
| all into. Imagine it was law that every medical device had
| to emit the numbers it displays on something like an ODB2
| port. Something that can be visually checked to be plugged
| in, be unplugged and replugged with no handshake, and
| handle daisy chaining so in the event the "network" breaks
| in two, or a device goes down, you still get information
| from the remaining network/it can reroute.
|
| For such a highly regulated industry... you kind of wish
| they would regulate. I guess status quo is also a
| regulation.
| HeyLaughingBoy wrote:
| Interoperability is definitely a problem. I've been in
| the industry for quite some time, and at one job we got
| to shadow med lab techs, since they were the operators of
| the machines that we built. Their workload is _insane_
| and after an hour watching them work, I could identify a
| number of new products that would help them. I brought it
| up to my management and learned that "marketing is aware
| of those problems and we're devising solutions." No idea
| if those solutions ever hit the market -- this was over
| 10 years ago.
|
| At the time, the solution to interoperability was to buy
| all your lab equipment from one manufacturer, who would
| use their own (usually proprietary) protocols to tie
| things together. That way, at least even if they weren't
| actually interoperable, the UI's and workflows were
| mostly consistent.
|
| A large part of the problem is that hospital IT is
| understandably hostile to anything connecting to their
| network, so all the stuff we were building at the time
| that talked to each other, had to use its own standalone
| network, or serial ports (ugh!).
|
| Standards like IEC-60601 or 62304 (my daily bread) are
| easier to adopt because they address patient safety. I
| suspect it would be much harder to mandate an
| interoperability standard unless you could show that it
| improved safety instead of "just" making the healthcare
| provider's job easier. Or maybe it exists, but just never
| came up on my radar.
| unsignedint wrote:
| One significant difference between verbal warning systems in
| airplanes and those in medical environments, such as hospitals,
| is the level of environmental control. In an airplane, the
| environment is highly controlled, with a single set of systems
| specific to that aircraft. In contrast, hospitals often have
| multiple systems operating simultaneously in the same room or
| nearby. This can lead to cognitive overload when multiple
| systems issue verbal warnings simultaneously. In such
| scenarios, tone alarms might be easier to manage and
| differentiate than multiple overlapping verbal warnings.
| g15jv2dp wrote:
| What's not clear from this webpage is whether these are actually
| used anywhere. Are they? I couldn't tell.
| thomasthorpe wrote:
| Yes, well, some. To gain certification, often something
| customers require, medical devices must comply with standards
| such as ISO60601 (hardware) ISO62304 (software) and ISO13485
| (process, quality management).
|
| The alarm waveforms described are within the scope of the
| hardware standard guidelines, sufficiently common that
| application notes such as this exist.
| https://www.ti.com/lit/pdf/slaaec3 [ti.com]
| HeyLaughingBoy wrote:
| > often something customers require
|
| A bit more than that. Certification is required in order to
| put your product on the market. Whether or not customers
| require it is irrelevant.
| davidw wrote:
| It gives me anxiety just looking at this. Add this to the list of
| things I don't want to work on.
| HeyLaughingBoy wrote:
| On the producing or consuming side? FWIW, I found the article
| interesting as I'm starting a new Oxygenator project so I'm
| probably about to become even more familiar with IEC60601 :-(
| davidw wrote:
| I don't want to work on software where bugs might cost
| someone their life.
| HeyLaughingBoy wrote:
| I get that, but it's very unlikely to happen. The benefit
| of your code vastly outweighs the potential downside. As
| engineers, we're used to only hearing about the problems.
| It's really gratifying when you hear from someone who says,
| "tell your engineers that they saved my life."
| blackeyeblitzar wrote:
| I absolutely hate the poor design of medical equipment found in
| hospitals. The worst thing by far is the constant beeping and
| noises in the room, which totally disrupts rest and hurts
| recovery. It is SO obvious that this hurts patients (and
| visitors), that I cannot believe the entire medical industry
| (nurses, doctors, hospital administrators, equipment makers,
| insurance companies) have failed to do anything about it. It also
| makes it hard to know if some sound is expected or if it is a
| signal that something is wrong. In addition to this, I've seen
| nurses make mistakes several times because the equipment is too
| confusing. Once, I had to page the nurse myself because the IV
| they thought they set up was not functioning and I was able to
| discern that from the screen on the IV machine (which said one
| particular drug was not active) but they had not noticed,
| essentially administering an imbalanced cocktail of drugs for a
| period of time.
|
| My take - the medical industry has too many barriers to
| competition, and it is too difficult for people who work with
| these things to do anything about it as well. It's unclear who
| the buyers are at a hospital or how a startup could reach them.
| It's also unclear what sort of interoperability (for example with
| Epic for charting) is needed. Regulations also make it difficult
| to get devices approved and investors are less likely to support
| a startup in this space.
| atahanacar wrote:
| >I've seen nurses make mistakes several times because the
| equipment is too confusing. Once, I had to page the nurse
| myself because the IV they thought they set up was not
| functioning and I was able to discern that from the screen on
| the IV machine (which said one particular drug was not active)
| but they had not noticed
|
| This doesn't sound like the equipment's fault.
| blackeyeblitzar wrote:
| Technically no, but watching them debug it and configure it
| made me think it's too complicated. They basically had to
| figure out the right sequence of buttons to hit.
| mschuster91 wrote:
| It's a necessity, a side-product of not having anywhere near
| enough nurses, assistant staff and doctors in hospitals.
| They're juggling alarms constantly (which have to blare in a
| cacophony) and speed from one patient to the next.
|
| _Ideally_ you 'd have a 1:1 (or better!) assignment between a
| single patient to a single nurse in critical care, 1:3 for
| patients that can't move around on their own (and thus need
| more assistance, even if it's just helping them to eat or go to
| the loo), and 1:5 to 1:10 for everyone else. The sad reality is
| that even in Germany, you have care home staff calling in the
| fire department to assist because there were just three staff
| in a night shift, having to deal with 170 patients.
|
| [1]
| https://www.morgenpost.de/berlin/article242110812/Kurioser-G...
| ler_ wrote:
| Thank you for bringing that up, understaffing affects
| everything and harms patients. No set of alarms will ever
| replace the benefit of having enough people working.
| blackeyeblitzar wrote:
| I don't disagree but I'm not sure how to make the costs of
| healthcare work with those ratios
| mschuster91 wrote:
| Get rid of bureaucratic bullshit and you'd get > 250
| billion $ a year [1]. Get rid of insurances and other
| middlemen and you'd get _another_ 450 billion $ a year by
| going for single-payer [2]. Then, get the homeless enrolled
| in insurance as well - even if the government pays the
| premium, _every single homeless person_ costs > 18k a year
| in ER visits [3], a lot of which could be prevented if
| these people could go to a doctor before they'd be sick
| enough to incur serious ER costs. And finally, get as many
| homeless drug addicts back into some sort of stable
| housing. A lot of drug usage "on the streets" is self-
| medication to cope with the immense stress that comes from
| being homeless. Yes, there will always be a certain
| percentage of hardcore voluntary homeless people, but
| that's way better manageable than the status quo.
|
| That should be way more than enough to hire enough nurses.
|
| [1] https://www.americanprogress.org/article/excess-
| administrati...
|
| [2] https://ysph.yale.edu/news-article/yale-study-more-
| than-3350...
|
| [3] https://www.newsweek.com/homeless-americans-are-
| costing-us-m...
| dmd wrote:
| About 15 years ago I worked for a medical usability firm. We
| did a review of the Baxter Large Volume Infusion Pump. Among
| dozens of other issues[1] we found, the absolute mother of them
| all was the stop button, which had been _overloaded_ to have
| multiple functionalities:
|
| If you push the button once, it would stop infusing drug into
| the patient.
|
| If you push the button twice, it would EMPTY THE SYSTEM - as
| in, run the pump continuously, infusing all remaining drug into
| the system, at high speed.
|
| We ran usability tests where we'd say to the nurse "wrong drug!
| stop! you're giving the patient the wrong drug!"
|
| 90+ percent of them did what any human would do - jab STOP over
| and over. Whoops, patient's dead.
|
| In part because of our report Baxter was forced to recall[0]
| hundreds of thousands of the pumps and pay for their
| replacements with competitors' products. The stock dropped by
| 30% in a day. Sadly I didn't short it, or I'd be [checks notes]
| in jail.
|
| [0] https://archive.is/s1wEU
|
| [1] like drug libraries where sometimes the units were
| displayed, sometimes they weren't, and sometimes they were
| displayed in your "preferred" units even though the number
| being shown was in a DIFFERENT unit and the system didn't
| translate it, just showed the wrong value.
| ano-ther wrote:
| I seem to remember that some of these sounds (perhaps the one
| with syllables) were originally part of a joke paper and that the
| author was quite astonished how they became part of a standard.
|
| Unfortunately, I cannot find the article anymore.
| tverbeure wrote:
| A friend of mine used to have a small side business selling
| loudspeakers for medical equipment. She order them in Asia and
| had her own little certification lab at home: heat chamber,
| impedance testing, that kind of stuff. Every so often, she'd
| receive an order of a few hundred speaker, and test them one by
| one.
|
| It's a low volume but high margin business. Some of the issues
| were the constant fight against the factory not following design
| requirements to cut costs, knockoffs etc.
| roughly wrote:
| The cardiac alarm tone is unexpectedly jaunty.
| graypegg wrote:
| Out of all of them, it's definitely the most "washing machine
| is done"
| strnisa wrote:
| The standardization of medical alarms was important when
| introduced, providing consistent and clear communication across
| devices and countries. However, with modern technology, these
| standards may now limit innovation.
|
| It seems to me that clear verbal alerts like "BLOOD PRESSURE VERY
| HIGH" could be more immediately understandable than tones. A
| hybrid system combining verbal alerts with alarm tones might be a
| good compromise for clarity and international usability.
| ncallaway wrote:
| I don't know, I kinda think if you're going to have verbal
| warnings you kinda need a centralized system that processes all
| alarms to triage them like in an airplane.
|
| If even 2 verbal alarms are going at the same time, it's going
| to create a chaotic environment.
|
| In a decentralized system, I think tones have less of an
| overlapping problem.
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