Day of week of procedure and 30 day mortality for elective surgery (2013) | Hacker News Reader

Day of week of procedure and 30 day mortality for elective surgery (2013)

bmj.com

188 pointsstanislavb83 comments

> Choosing Monday for a surgery increases your chance of success 2 times

The title seems poorly worded. The researchers studied mortality rate, not success of procedures. Since these were elective surgeries, I assume the success rate was high. If your surgery has a baseline success rate of 90%, what would it mean to increase that 2 times?

The conclusion of the study was instead that the odds of death were 44% higher on Friday compared to Monday, and 82% higher on the weekend compared to Monday. Basically, there was a gradual increase in the odds of death from Monday to Thursday, but a big jump up on Friday and again on the weekend.

Almost certainly the selection bias plays a major role - surgeries done early in a week are different than those scheduled later in the week.

Yeah, this reminds me a lot of the "Impossibly Hungry Judges" problem[0].

[0] http://nautil.us/blog/impossibly-hungry-judges

This is a great article. The original paper was in my head as a truth, and I've revised that since reading this post. Thanks!

> If hunger had an effect on our mental resources of this magnitude, our society would fall into minor chaos every day at 11:45 a.m.

...this has potential!

Scrape GitHub, find closed issues marked 'bug', do a blame on the offending line or lines, find the timestamp and plot.

Has potential for the exact same selection bias as the judge study, you mean? See if we can discover some impossibly hungry programmers.

It would be a pita to control for time zones, or even culturally different lunch times and eating habits

Git commits do embed a timezone in the commit timestamp. And while lunchtime will vary by person, there may still be a visible effect around common lunchtimes over a large number of people.

Time is an illusion; lunchtime, doubly so.

The hypothesis I would personally register is that bugs increase after 5:30 PM, and that this effect drops off in late evening hours.

Basically, that compelling one's employees to stay late is an anti-pattern, where one loses more than one gains.

I read this as 'pita' as in 'pita bread'. A clever reference to lunch time if that was the intention? Culturally different too as we don't often eat pita for lunch here, but I imagine it's common elsewhere.

Having been through the court system twice, from experience I've seen dockets arranged so that more severe cases are saved for last, and cases with a quick disposition (like probation or fine) are taken care of first.

Edit: This allows the law officials to remove offenders faster from the courtroom.

That's certainly a possible confounding factor that should be investigated, but let's not jump to conclusions.

Jumping to the conclusion that Monday surgeries are simpler could hide an important phenomena if that's not the reason Monday surgeries have lower 30 day mortality rates.

They do take this into account in the text. Odds ratios imply less risky procedures were normally done on weekends anyway, and you see the effect on all days other than Monday (to a lesser extent).

Yes, they do mention this - though it can be challenging to account for all factors. You can't quite correct for variables that are not collected/known.

I am willing to accept bias, but Why would Monday surgeries be statistically different from Wednesday? Clearly weekend surgeries might be different, but the effect is still present Monday-Thursday. I don't work in healthcare so there might be a selection bias that I am blind to, and I am curious if you have a bias in mind. Also they did track specific procedures and for all but one (with a low n) the procedures tracked the results.

If I were a surgeon, after a few days off of leisure to rewind, I certainly wouldn't start with my most risky, potentially problematic cases. Instead, I would try to pick operations that were the most straightforward. These would be almost like "warm ups" for more complex surgeries I would do later in the week.

I'm also not a surgeon...

Sure, but that implies that surgeons control the operating room schedules. I am not sure that's true (it might be), but it's a contested resource in most hospitals.

Outside of emergency surgeries, I imagine anything scheduled that isn't of immediate risk surgeons have a reasonable amount of control over, given of course the magnitude and distribution of surgeries that need performed.

I can't imagine they don't look at their schedules regularly and talk to whomever does scheduling to make their lives more bearable.

When they're on ER rotation, surgeons of course really have no possible way to manage this. My question would be: what's the ratio of emergency to planned/scheduled operations?

ER cases might also not serve as a proper control - the types of injuries and accidents over the weekend will likely be different from those during the week days

The amount of influence a surgeon has in her schedule varies from place to place and specialty to specialty. It ranges from little control, to being able to look at a calendar and pick the date. Also, most surgeons do not operate on all days. In most large hospitals, surgeons have set OR days (ex. Monday, Tuesday, and half of Thursday) every week and it is incredibly difficult to change that.

Could just be that they are the most rested then. Or just how the surgeries are ordered. Probably a simple explanation.

The problem is with multiple-day recovery periods after the surgery. The later in the week your surgery is scheduled, the more likely you'll overlap with the weekend when care is hypothesized to be lower quality.

Part of me also wonders if people who elect to have Monday surgeries are in a better socioeconomic place to take more time off to recover.

I've had a bunch of surgeries and I wasn't given much of a choice as to when they were scheduled. These were orthopedic surgeries, but nothing urgent (stuff like a labrum repair or whatever). I was simply told to be at the hospital/surgery center at X time and that was that.

uhh guessing it halves the % of failures is what they actually mean

30k deaths / 4 million procedures is 0.75% death rate

going from 99.25% to 99.6% survival isn't doubling anything

also 'success' doesn't appear anywhere in this article, guessing '30 day mortality' is the thing they're measuring

Yeah that's the main reason i had to read it. Even if you got to 100 percent on Monday that would imply only 50 percent success on other days. Nobody would have an elective procedure with that low success rate.

Success rates are often not that high. Also depends on the exact definition of success. Say for carpal tunnel, from that I've read, the "there was any improvement" success rate is about 90%, but the "fully healed" success rate is as low as 15%.

It’s 99ish% odds of no event. Going from 0.4% to 0.75% is pretty close to doubling the odds of seeing an event though.

For context for future readers: The submitted title was "Choosing Monday for a surgery increases your chance of success 2 times", and has since been changed.

https://news.ycombinator.com/item?id=22020870

While I recognize it's an attempt to highlight the "takeaway", the submission title (currently "Choosing Monday for a surgery increases your chance of success 2 times") seriously distorts the actual study contents.

It's not analyzing "success" of the surgery, but "30-day mortality for (almost) any cause". (While death caused by the surgery is definitely failure, the absence of death isn't necessarilt "success".)

Also, there's no evaluation of "consciously choosing Monday" as a causal factor. There could be all sorts of pressures causing the surgeries on different days-of-the-week to have different risk factors, even if they're all "elective". (As they note: "One of the weaknesses of using administrative data is that we were unable to completely adjust for inherent selection biases that probably exist for elective procedures that are scheduled on weekends.".)

I can believe there's some effect of patient choice, possibly related to staff exhaustion, post-op complications happening during under-resourced weekends, but expect a lot of the effect found here to be due to factors pushing certain surgeries/deaths into certain days (and arbitrary categories that might have affected inclusion).

Submitted title was "Choosing Monday for a surgery increases your chance of success 2 times". That breaks the site guidelines, which say: "Please use the original title, unless it is misleading or linkbait; don't editorialize."

https://news.ycombinator.com/newsguidelines.html

Cherry-picking the detail you think is most important from an article is a form of editorializing. If you want to say what you think is important about an article, please post it as a comment to the thread. Then your view will be on a level playing field with everyone else's.

I'd believe it.

Rushed to the hospital on a Saturday night when my father in law suffered a massive heart attack... and he was held stable for almost 2 hours before a surgeon capable of working the situation was able to make it in and insert a stent.

It seemed strange to me that a hospital would have a schedule like that... where most doctors work 9 to 5 monday to friday, and most everybody goes home for the weekends.

People can fall ill at any time. Although I suppose the majority of people would only notice that they were ill and come into the hospital during regular business hours.

I noticed this because he was in an induced coma for a few weeks.

At night they lock the place up so tight there is literally only one door in the emergency room that is open to the outside. Something about them being worried about narcotics thefts.

That was a frustrating learning experience our first evening in the hospital, I tell you!

Thankfully he pulled through with flying colors!

The emergency ward is basically a whole new operation on the side. It is not feasible to keep it staffed with all specialties at all times, due to low volume and sparse distribution of those special cases, compared to scheduled weekday procedures in the hospital. There will be a few doctors doing shifts (sometimes just one), and the rest on call. In smaller areas there might only one or two of each specialty, and they obviously cannot be available 24/7, but will end up jumping out of family activities, sports, school and sleep basically all the time.

> At night they lock the place up so tight there is literally only one door in the emergency room that is open to the outside.

As another commenter below said, the ER is an entire business model on its own. The goal of an ER is to treat your acute illness or injury and then proceed to push you into a dedicated room to maintain stability. Most (unsourced) emergencies that come into the ER can very likely be stabilized by RN’s and consultation from a MD/DO. honestly, most orders in a setting like these tend to come from the bottom up (RN to MD for approval) if there is a trustworthy relationship between them. Depending on the severity of the patient, of course.

For an example, on 12/30 @ 2345hr, I got extreme abdomen pain and ended up in the ER. On 12/31 at 0200hr, the DO came in and palpated my stomach and concluded I had appendicitis. @ 0300 I was having a CT scan done. @ 0400 the DO was on the phone with the on-call general surgeon to consult with him about surgery for acute appendicitis which led to the eventual rupturing of my appendix. It was then at 1100 when I was in the operating room. Up until this point, every aspect of pain management (morphine every two hrs) and IV fluids were completed by a RN.

For my case, there was no need for a specialist to be on the clock. One was easily in reach but up until that next morning, I had no real need for them besides the one DO who came and put their hands on me as a formality prior to doing a CT scan. I’m mostly just thankful they have specialists to call to begin with.

I think you missed the word "elective", I guess the whole point was to remove emergency surgery from the study.

I think the principal is still the same. Surgeons do not perform surgeries every day. They usually have some days of the week they meet with their patients in an office setting. And then other days of the week they are in back to back surgery all day. It would be interesting to know what, if any, industry standards determine which days are allocated for which. Or if there is a hierarchy of surgeons who get "dibs" on scheduling their surgeries on Mondays.

I can't find a source, but 70's-era wisdom I got from my grandfather was when buying an American car, buy one assembled on a Tuesday. People are hungover on Monday, Tuesday is their best work day, it's downhill on Wednesday and Thursday, and they're checked out on Friday.

How can you possibly figure out when a car was assembled?

The sticker on the door jam with the VIN usually has the month and year.

The VIN has an indicator for which factory it was built in. You may find rumors/wisdom/witchcraft around one factory having better quality controls compared to another.

Which day of the week your car was "Manufactured" probably isn't a thing that even makes sense. That's just going to be final assembly. Each individual part will of course been manufactured on a different day. Even if you believed the magic of Tuesday is the best day, do you want to know the day your doors were hung on the hinges, or the day the pistons were machined?

I remember that from the 70's as well.

It's surprising that Monday was the best day. I'd expect the surgeons and staff to be impaired from weekend activities, and back to normal on Tuesdays. Tuesday was not much different from Monday and may be the wiser choice, in case your surgeon is a hard partier.

When I was a mechanic, we used the joke "must have been built on a Monday" when a car came back for repeated issues, but I think it was lighthearted humor at best. I'm not sure how much truth there was to it.

Pro tip: if getting a colonoscopy, always always get the first appointment of the day. I work in med devices and ummm those scopes still have poop left over between procedures. Its not harmful, but still...

Why are they not cleaned thoroughly? Just curious.

And if they are and yet still contain fecal matter, how does going in the next day help? Your appointment is still after someone else's. Do they use a new scope?

Theoretically, some bacteria could have died overnight, which would be good. In general, simple instruments constructed of stainless steel or other solid non-porous materials are easy to wash off and autoclave. Complicated constructions in which multiple parts fit precisely inside other parts constructed of different materials are not easy to wash and autoclave. Scope manufacturers would be encouraged to design more sensibly if physicians could be held accountable for cross-contamination. This would require a more aggressive regulatory regime.

I am trying to make sense of the original post while stipulating that the claim about it not being harmful is true. Assuming only sterile fecal matter is left on the device, how does having an appointment the next day help?

He seems to be suggesting that the fecal matter can be avoided by a gap of 16 hours versus a gap of (say) 30 minutes. I'm at a loss for the mechanism by which this might occur.

I work on the video side of things and know nothing about the mech eng part. What I can tell you is that during the day there is definitely fecal matter in the scope one case to another during the day after after autoclave and sterilization. The first case of the day, the scope is clean. I don't know what's different about overnight processing in the sterile processing department. And I've seen this at many hospitals. There's been some startups that have tried sheaths to cover the scope but could not make it work.

The difference you cite between the per-patient and daily cleaning, disgusts any human who learns of it. The only studies showing that sort-of clean scopes are safe were funded by the scope manufacturers. This is problematic.

There are design issues currently being worked on to minimize crevices and spaces where bacteria may remain (redesign) or avoid the issue completely (design and implement disposable endoscopic heads)

I'm no expert but aren't you exposing one patient to the previous patient's poop? There could be anything from a lovely c-diff payload to something the next guy is allegeric to like nuts. As a layperson it hardly seems harmless.

I have a feeling OP means they are sterilized or autoclaved but some (now non-dangerous) particles remain as there is no medical point in thoroughly cleaning them after sterilization. Which would make sense.

People get a bit paranoid about how "clean" things are. I for one am not as concerned about how "clean" something looks but how potentially harmful it is to my livelihood. Looks can be deceiving, either way, without considering the entire situation.

Something that looks unclean can be sterile and harmless while something sterile and visually clean can be incredibly harmful as well (e.g. water with certain toxins or compounds).

Exactly.

The first (not sure if reputable) article I came across regarding this suggests that this is absolutely a major public health concern and maybe people working in medical devices passing it off as harmless is part of the problem...

https://www.focusforhealth.org/need-a-colonoscopy-the-one-qu...

Wait for real? How would that not be insanely dangerous and risky in terms of fecal cross contamination and disease transfer? Do you have a source for standard treatment procedure to not include using a sterilized scope?

Huh. I asked my retired endo nurse mom about that, and she said (at least at her hospital), that’s not possible.

So, I’d recommend not going to the hospitals this dude services.

Company that tried and failed to make a sheath: https://www.giejournal.org/article/S0016-5107(08)00014-X/abs...

Some of the clinical challenges https://www.sciencedirect.com/science/article/pii/S200103701...

With the exception of an actual emergency (i.e. "We need to see inside them or they will die, we'll deal with the infection risk later) doing this in most hospitals I know is one of the better ways to sign up for the infection control team paying you a visit.

If they're not being cleaned adequately report it to the medical board.

A mortality rate of 0.7% for elective procedures sounds high. What counts as elective but carries such risk? Is it similar in other countries?

Anything that is scheduled in advance (i.e. not imminently life or limb-threatening) is elective. That includes most transplants, coronary bypasses, removing a tumor from the brain etc.

They aren't measuring the mortality rate of the procedure. they are measuring this:

"Death in or out of hospital within 30 days of the procedure."

If I am already on my death bed (for lack of better word), the procedure's mortality rate is probably not swaying it much. Also, couldn't find if they would include something like a lethal car accident 28 days after the procedure or not.

> An elective procedure was defined as “elective: from waiting list,” “elective: booked,” or “elective: planned”

High risk procedures seem to be cancer related and specific excisions.

If one uses an "episode of care" framework, mortality within 30 days of treatment is a standard metric.

https://www.cms.gov/Medicare/Medicare-Fee-for-Service-Paymen...

Things like getting hit by a car are referred to as "competing risks". The authors lumped all deaths together: "We defined the mortality outcome as any death occurring within 30 days..."

But there are other ways to handle this, with increasing levels of annoyance/sophistication.

The problem is "elective" has a different meaning in doctor-speak than in common usage. "Elective" doesn't mean it's something you can reasonably decide to have or not, in doctor-speak it's the opposite of emergency. If it's put on the schedule rather than done stat it's elective, no matter how serious the procedure.

Are there any other interesting things like this that people know of? I guess you could consider them advanced life hacks in a way.

One things I was thinking of is trying to schedule meetings right after lunch. I'm basing this on the research of judges being more lenient after lunch. https://www.theguardian.com/law/2011/apr/11/judges-lenient-b...

This depends on the kind of meeting you're having. If it's a negotiation with a counterparty, then absolutely schedule for right after lunch. It'd be better if they were a little insulin drowsy after lunch. Ideally you'd be buying them lunch, eating little (or mostly vegetables yourself) while they enjoy an expense account meal.

On the other hand if it's an internal meeting with your team, you want to get them at peak alertness, 10-11 (people settle in for the day, but not hungry for lunch yet), 230-4 (the post lunch blood sugar swing has settled down but people aren't itching to leave just yet)

I have always scheduled job interviews in the morning because the hiring manager is more alert and (I read somewhere) in a more upbeat mood before having to deal with tragedies of work. I extended this later in life to making sales calls as the first thing I do in the morning because I am more awake and alert.

Switched on its head, I prefer morning interviews because I can really focus on the candidates without thinking of (or being annoyed for stopping work on) a deep problem I began working on. If a sales person calls me in the morning, I'm more likely to answer and have a conversation.

This is why I only work 3 days a week.

The stuff I do really taxes my mind and there is no way I would be able to do it well any more than that.

Monday’s Tuesday, and Thursday.

Still, patients complain.

Go elsewhere.

I'd rephrase the submission title to 'choosing the first working day of the week for a surgery doubles your chance of success"

In the US it is Monday as in the title, but in other countries, Israel for example, it would be Sunday.

Israelis reading HN will "get it" when reading the current title.

The study was done in England. Unfortunately the results can't be generalized to the rest of the world.

If a doctor tells you to get a Tonsillectomy on Sunday, don't push back too hard. Get the Tonsillectomy. You probably really need it.

I expect this is a large portion of the effect that this study is measuring.

It’s for the exact same reason that you deploy code on a Monday... if something gets fucked you have a week to stabilize it before the pager crew takes over.

Maybe it's because surgeons on average tend to put off more difficult surgeries to a later day in the week. They don't want to come into the operating theater after a weekend of hard drinking and have to do a complex brain operation on Monday morning.

So they will organize their schedule so that they only do routine low-risk operations on Mondays.

I don't know. "No change on Friday" also sounds like a reasonable rule when it comes to essential parts of the human body.

Reminds me of a study they did for... chance to get parole approved based on time of day. Findings were early in morning and after lunch breaks was the most successful time. Just before clock-off and lunch inmates chances were reduced.

The effects reported in that study are probably not real [0, 1].

[0]: http://nautil.us/blog/impossibly-hungry-judges

[1]: http://journal.sjdm.org/16/16823/jdm16823.html

What about during football season? Doctors and nurses are pretty serious folks, but I can see them having a few too many during the exciting football games. Not all of them, of course, but some like the games.

Perhaps (2013) should be added to the title.

I wonder if posting this on Saturday was intentional, and if it has any outcome on its success on hn:)

My last two surgeries were done by a doctor who only had Wednesday as a day for surgeries.

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