Tuesday, September 01, 2015

Family medicine board examination 2015: One last time.

I’m taking my family medicine board exams one last time. This is not entirely sensible. It’s been 21 years since I did family medicine, and 17 since I last saw a patient. I’m unlikely to practice again. The exam will be difficult; my brain is old and cruddy. (Long ago I did rather well on these, but it does help to actually practice medicine.)

Still, for one reason or another, I’m committed to doing the exam this November. I’ve slogged my way through the ABFM’s intricate preparations, including, for the non-practicing candidate, 6 self-assessment modules (SAMs) and one “alternative” module (which was quite awful and may have been since withdrawn). I even managed to meet the under-documented CME requirements [1]. The expensive Self-Assessment Modules varied from quite good to rather poor; alas the simulations are not worth continued investment [2].

When I’m done I’ll revise this post with what I end up with. By far the best guide I’ve found for someone like me was something written in 2008 (*cough*). I’m basically following my old recommendations (including ignoring audio CME/podcasts). For example:

  • ABFM | Exam Preparation: look for the tiny links at bottom to Study Tips and 2-week checklist. Some of this advice is wrong for me - and probably for most people. Still worth a read.
  • ABFM | Exam Content: this page hard for me to find - maybe my problem. I focus on topics with 5% and above.
  • I have old online medical notes written back when we thought HTML would be a good format for knowledge sharing and documentation. How naive we were! My medical notes started out in pen, moved to Symantec MORE 3.1, then FrontPage/HTML and now they’re back to an outliner (OmniOutliner 3). I have to write to learn. When I’m done I’ll attach a version of my notes here, but they’re really only going to be useful for me.
  • SAM Module Review: The SAM modules were a mixed bag, but the question explanations are superb summaries of current/expected knowledge. I’m mining those for my notes.
  • ABFM in training exam: The ABFM provides 3 years of teams. I’m studying these in depth, identifying any areas of strength, guiding my study, and generally awakening old memories.
  • Online references: this has changed, and not for the better. There’s much less available for “free” online than there was in 2008 [3]. Only Scott Moses’ self-funded hobby/obsession remains - the FP Notebook. So I’m buying selected paper references [4] like the venerable Washington Manual and Sanford Antimicrobial therapy. Some of my old textbooks (EKG interpretation) still work.
  • Monthly Prescribing Reference (print version): still evil (drug money funded), still remarkably useful. Trick is to know what drugs are actually used vs. what are legacy — would be nice to have a version filtered by popularity.
  • AAFP Board Review prep: skip over the expensive and inefficient modules and find the free (38 credit!) Board Review Questions. I think this is what the ABFM “exam prep” document was warning against. Needless to say, I’ll be sampling these, though Emily recollects they’re less useful than the ABFM in training exam materials.

I’m alternating topical work (reviewing Sanford, relearning EKG interpretation) with review designed to rebuild old memories. My medical knowledge network is frayed and fragmented, but there’s a lot of it. Much of my preparation is really resurrection. I've brute memorization ahead - reading, closing eyes, regurgitating. Then exam-guided note review and expansion.

It will be interesting to see how it all goes. Failure is certainly an option.

- fn - 

[1] Dear ABFM: Please note the current cycle progress tracker omits CME requirements but the future cycle includes CME requirements. Could be fixed.

[2] In the late 80s through early 90s we used to get 360K floppy disks each month with a unique DOS based medical simulation. I cannot, just now, remember what medical publisher did them (something Cardinal?). I remember them as quite excellent, I featured them in our residency computer-based training program.  Several clinicians, likely retired now, did some serious work on those. There really is no modern equivalent. Which is a kind of interesting.

[3] UpToDate is by far the dominant online resource for medical information — and it’s very expensive. (Priced for organizations.)

[4] See [2]. Also the movie Groundhog Day.

Thursday, August 27, 2015

Pectus Excavatum complications - beware neck strike during barbell Clean

I am deformed

Current Management of Pectus Excavatum [jf: depressed sternum associated upper chest]

Pectus excavatum (PE) is one of the most common anomalies of childhood. It occurs in approximately 1 in every 400 births, with males afflicted 5 times more often than females. PE is usually recognized in infancy, becomes much more severe during adolescent growth years, and remains constant throughout adult life. Symptoms are infrequent during early childhood, but become increasingly severe during adolescent years with easy fatigability, dyspnea with mild exertion, decreased endurance, pain in the anterior chest, and tachycardia. The heart is deviated into the left chest to varying degrees causing reduction in stroke volume and cardiac output. Pulmonary expansion is confined, causing a restrictive defect.

Repair is recommended for patients who are symptomatic and who have a markedly elevated pectus severity index as determined by chest X-ray or computed tomography scan…. Operation rarely takes more than 3 hours, and hospitalization rarely exceeds 3 days. Pain is mild and complications are rare, with 97% of patients experiencing a good to excellent result. The new minimally invasive Nuss repair avoids cartilage resection and takes less operating time, but is associated with more severe pain, longer hospitalization and a higher complication rate, with the bar remaining for 2 or more years…

My chest wall deformity is moderately severe, not as impressive as the wikipedia photo. A correction attempt was made at age 15 or so, but without the reinforcing “bar” used now. The post-operative pain then was not “mild”, it was exquisite — at least during breathing. The collapsed lung or two probably didn’t help. (I suspect my surgeon was pleased I survived). The deformity recurred, but my operative experience cured my psychic distress. I decided having an “ant’s swimming pool” wasn’t so bad after all.

Reading the above description it seems I can blame my unimpressive athletic career on my chest wall. Come to think of it, I did feel quite tired this morning on the fourth round of 400 meter sprints and as-many-reps-as-possible box-jump-over burpees. [1]

All of which is a prequel to new knowledge. I’ve figured out why I’m the only person at CrossFit who tends to hit their neck when doing a barbell “Clean”. With most people, even with poor technique, the upper chest pushes the bar away from the throat. With me it directs the bar towards my throat.

So there you go. For all the other persistent Pectusoids out there, if you are doing a barbell Clean pay attention to hitting your mid-body target and work on your technique — your pectorals will not save you.

[1] Sarcasm here should hint that this abstract’s disability description is debatable. In reality it is unclear how much cardiopulmonary compromise there is, and whether surgery really helps. Some articles suggest it helps cardiac function but worsens pulmonary function. There are big nocebo (deformity) and placebo (surgery) effects that make outcome evaluation difficult.

Update 8/31/2015: After writing this I realized I have a genuine CrossFit disability. I can’t do an “Rx” pushup, because I can’t touch my upper chest to to the ground (lower chest gets in way, not to mention my shoulders and head). During WODs I use an Ab Mat as a target, but I couldn’t do that in competition.

Tuesday, August 25, 2015

Mountain biking: A good sport for heavy kids?

I help out with a High School mountain biking team; it’s a team #1 rode with last year. (He might be first special needs student to compete in a NICA high school race, though I wonder about the Utah league.) It’s a sweet deal — I do adult things, carry the first aid kit, and help with team communications; in turn I get to ride with a great group of adults and kids while I get quality coaching by listening and practicing with our riders. #1 helps too, I’ve made it part of his post-high school “transition” training.

One of the things I've heard from the coaches is that heavy kids tend to do well with mountain biking. The bike takes a lot of weight off knees and hips and, by necessity, these kids have powerful legs. Weight isn’t a big disadvantage on the downhills. Being heavy does make climbs harder, but that work boosts conditioning. Heavy kids who go to practice lose fat and gain muscle, so they improve faster than slimmer riders. That rapid improvement is a powerful reinforcer. If they persist they keep the powerful leg muscles and lose fat — and become quite competitive.

I see the logic. It would be interesting to get some data, but I couldn’t find any studies in the medical literature. It could be a fun research topic. 

[1] He may be the only special needs student, so far, to compete in high school mountain bike races.

Wednesday, August 19, 2015

Amazon reviews show a Shimano SPD pedal has a safety defect. Do Amazon and Shimano have a duty to report under US law?

I’ve sent two sets of Amazon purchasesed SPD pedals to Shimano for warranty replacement in the past month. I’d used each set for 2-3 months when they developed bearing clicks.

That could be bad luck, or it could be Shimano has lost control of its Chinese manufacturing pipeline. I’m just too small a sample to know.

But that’s not what I’m curious about.

I’m curious about Shimano’s apparent disinterest in the Amazon reviews of the Shimano PD-A530 SPD Dual Platform Bike Pedal. Many reviewers, over several years, have described the same safety issue I ran into. These pedals have two sides, a flat side for shoes and a “cleat” (confusingly these are called “clipless pedals") side that locks onto metal tabs attached to bicycle shoes. The clip lock setting is far too tight, at the default setting it’s quite difficult to remove a shoe from the pedal. Maybe the spring is the wrong tension, maybe there’s some other design error, but this is dangerous. Reviewers report falling over in traffic due to excessively tight clips.

The workaround is to set the adjustment bolt to its minimum setting (though the bolt is more cheaply made than other SPD pedals, so you have to work it a bit to make sure the nut slides down). On every other SPD pedal I’ve worn over about 15-20 years this would be too slack, but on these pedals it’s about right. Of course a lot of cyclists won’t know to do this, or won’t immediately recognize that the pedals are miscalibrated. It’s a persistent safety defect.

Under US law both Shimano and Amazon have a duty to report safety defects...

Duty to Report to CPSC: Rights and Responsibilities of Businesses | CPSC.gov

If you are a manufacturer, importer, distributor, and/or retailer of consumer products, you have a legal obligation to immediately report the following types of information to the CPSC:

… A defective product that could create a substantial risk of injury to consumers...

… Failure to fully and immediately report this information may lead to substantial civil or criminal penalties.  CPSC staff’s advice is "when in doubt, report.” ...

… 

What if I receive information that reasonably suggests my product could create a safety or health hazard but no reports have been received alleging that actual harm or injury has been suffered?

You must immediately report the information about the product. The law does not require injury or harm to have occurred….

It’s clear these pedals have a defect, though a defense lawyer would argue about “substantial risk of injury”. After all, it’s the nature of clipless pedals to reduce foot-to-ground time, and a lawyer would argue that only knowledgeable people should buy a clipless pedal, and thus know how to adjust them.

It would be unwise, however, to rely on the kindness of US courts. I suspect if Shimano’s lawyers read the Amazon reviews they’d recommend doing a (confidential) CPSC report and fixing the darned pedals. Judging by the age of the reviews, however, they haven’t done the latter.

Which is interesting. Why doesn’t Shimano read Amazon reviews of its products? And what are Amazon’s obligations as a distributor or retailer?

Great questions for a law school class ...

Monday, August 17, 2015

And now for something somewhat different

A somewhat wise traveler walks a path in deep desert.

He comes across a turtle that has fallen on its back. Having some wisdom he carries the turtle to its shelter. As he turns to his path a clap of sound and light announces a Djinn.

“Oh wise traveler, you have proven your worth. For you I grant a great gift. I shall open a gate to the garden of paradise. From there you can choose a flower of immortal beauty to bring you joy and peace for all your life. Come and enter …"

“Ok. Stop there. I know this one. It’s that paradox of choice schtick. I enter the garden and everything is so wonderful my brain is like, totally blown. I wander the path but, of course, I can’t go back. Only forward. Every flower is more beautiful than the last — but I can only pick one. At first my path seems unlimited, but then I see the end in sight. I start to panic. Finally, in desperation, I grab the last flower. It’s kinda nice, but I’m left a bitter wreck for all the better flowers I coulda picked. Yeah, nice try, but I wasn’t born yesterday. Get thee hence Devil!"

The Devil, for the traveller has seen correctly, smiles and tips his hat. You are indeed wise, he says. Then he blasts the not-wise-enough man to eternal hellfire. [1]

When the Devil plays, you let him win.

-

My job died.

Our relationship lasted between 16-20 years, depending on whether or not I count time at an acquired startup. I started out a country doc, did a health informatics degree (thank you NLM), and I became a corporate health care IT R&D guy. For lack of alternatives I was "product management", but mostly I invented and implemented tools for health care workers to use - usually for patient care, more recently for analytics and population management. My real love was making docs smarter — that’s why I went into the business. In my GP days I was frustrated by not knowing the right stuff quick enough to provide the best care to my patients.

We had our ups and downs my corporation and I. My place in that world required skills I wasn’t born to; it was a fascinating challenge to learn those and survive (many thanks to several of my managers and mentors!). The corporation had its own issues [2], so the relationship required mutual forgiveness as well as mutual need. Like most relationships. Even during not-fun times the job was good for my family.

Alas, over the past few years the business changed. Eventually there was little need for a clinical decision support expert. Even I couldn’t see a way to justify my cost — the work didn’t exist any more.

My job died, but it left me an inheritance -  some time to choose my flower. Or invent it.

-

When I have to invent a solution, I look for constraints. Constraints are my friends; without constraints choice explodes. I have some constraints.

Age is a big one - I can see the garden’s exit. My exercise hobby gives me back some things, but it doesn’t change time. It would be good for my family if I earned some money. My family medicine board status expires this year, so i have to make a choice there. My family is strongly rooted, for the moment, in the most excellent Twin Cities of Minnesota. I have duties to my family that are perhaps above average.

Within these constraints there are things I’d like for myself. I’d like to give something positive to the world, something that might last a few years, something that I have a meaningful part in choosing and building. I would prefer not to join another large publicly traded corporation; I’ve done that one. I have a particular interest in cognitively disabled people. I’d like to do something I haven’t done before.

-

I did decide to take my (last) family medicine board exams. Over the past 3 weeks I’ve completed the qualifications to write the board exam in November. That process was considerably more painful than it needed to be, but that’s not my battle to fight (age teaches something). Preparing for that exam will take me 10-20 hours a week for the next 4 months.

I have technical debt from years of juggling work and family and health to manage. I’ve had a surgery I’d delayed. I’m cleaning up finances that got cluttered over decades. Family photos and videos, home stuff — things like that. More importantly, focusing on some special needs of my children, and taking each child on a plane trip (Montreal and San Francisco down, next up - London!). Oh, and taking my 93 yo father to visit his sister in San Francisco (just keep breathing for another 3 weeks everyone). That’s taking another 10 or so hours a week.

Then there’s exercise - mountain biking, road biking, CrossFit, inline skating — most of which also serves the needs of one child or another. That’s another 10-15 hours. Household maintenance takes time, it’s been a rough month for bikes and phones and computers. Writing, because that’s how I think and pay my geek dues. Exploring new tools and techniques especially on my post-corporate MacBook Air [3]. Learning FHIR and JSON data wrangling, catching up on 5 years of JAMIA articles, and other deferred professional obligations.

That all leaves a few hours a week to figure out my next move.

I’ll probably write about it.

- fn -

[1] I remember reading the original version of this story, but Google can’t find it for me. Maybe it was another universe. Related: "Life can only be understood backwards; but it must be lived forwards."

[2] Contrary to the Supremes, corporations are not people. They have their share of quirks though; partly cuz they contain people, partly because they’re slouching towards Bethlehem.

[3] It is insanely bad luck to say that this is the most trouble-free and immediately useful device I’ve every purchased. I love buying mature Apple hardware, though I note that the iPhone 6 and new MacBook have had less quality issues than I expected. Now if Apple can only fix their software quality issues and seven years of lousy products ...

 

Tuesday, August 11, 2015

2015 vs. 1910 - which era has more future shock?

Remember Alvin Toffler’s Future Shock (helps to be old)?

Wikipedia, via this:

"Toffler argues that society is undergoing an enormous structural change, a revolution from an industrial society to a "super-industrial society". This change will overwhelm people, the accelerated rate of technological and social change will leave them disconnected, suffering from "shattering stress and disorientation" – future shocked. Toffler stated that the majority of social problems were symptoms of the future shock. In his discussion of the components of such shock, he also coined the term "information overload”."

Toffler was wrong about his era, and probably wrong in general. 21st century China shows humans can tolerate a vast amount of technological and social change and keep on moving on. Future Shock is more like a winter carpet zap than a lightning strike.

It can still sting though. This past week, for example, we realized landlines are finally gone — at least in Minneapolis St Paul. 

Yeah, I know. They were supposed to be dead years ago. Ahh, but that’s the trick. What I remember in 1994 is that by 2000 we were all going to have fiber to the home; voice communication would be VOIP and too cheap to meter. It didn’t work out that way. It’s easy to predict the Future, it’s hard to predict when the Future will happen.

Instead landlines seemed to slowly fade. No big changes. For various reasons we kept our home number on a landline. We didn’t notice that Saint Paul Minnesota was down to a a single provider of landline services - CenturyLink. We didn’t notice the 30% drop in CenturyLink's share price. Then one day our CenturyLink landline malfunctioned, we lost net service, and we couldn’t get it repaired. We’ve been without landline service for two weeks; a repair guy may drop in this Thursday. Maybe.

I switched our net services to the only alternative our benighted metro area has - Comcast. I forwarded the home number to our cell, and, because our security system is landline based, we wait for a repair while figuring out what to do with our identity-associated home phone number.

The line will be repaired, or not, but that won’t change the fact that for Saint Paul, Minnesota, the landline era really has ended. A wee bit of Future Shock for old folk, and a minor puzzle for our kids (who have almost no understanding of how anything connects to anything else).

Which makes me think, again, about how this era compares to the early 20th century, when horses went from vehicle to entrée, the kerosene industry collapsed, and balloons turned into airplanes. Consider the auto transition - the first mast produced automobiles were sold by Olds in 1902, by 1910 there were more automobiles than horse buggies, and by 1920 buggies were mostly gone. So a 20 year transition. Not that different from the timeline of our landline decline, but far more disruptive.

On the other hand, landlines and horse buggies are physical things. They have a lot of momentum. What about transitions in virtual things? Can the speed of transition there make our era more bewildering than, say, 1910?

On reflection, I have to say not. That automobile transition is truly incredible. We still can’t compare. Maybe when the AIs take over..

See also

Wednesday, August 05, 2015

Donald Trump is a sign of a healthy democracy. Really.

I’m a liberal of Humean descent, and I’m a fan of Donald Trump.

No, not because Trump is humiliating the GOP, though he is. Of course I enjoy seeing the GOP suffer for its (many) sins, and it would be very good for the world if the GOP loses the 2016 presidential election, but Trump won’t cause any lasting political damage. Unless he runs as a third party candidate he’ll have no real impact on the elections.

I’m a fan because Trump appears to be channeling the most important cohort in the modern world — people who are not going to complete the advanced academic track we call college. Canada has the world’s highest “college” graduation rate at 55.8%, but that number is heavily biased by programs that can resemble the senior year of American High School (in Quebec, CEGEP, like mine). If we adjust for that bias, and recognizing that nobody does better than Canada, it’s plausible, even likely, that no more than half of the population of the industrialized world is going to complete the minimum requirements for the “knowledge work” and “creative work” that dominates the modern economy.

Perhaps not coincidentally about 40-50% population of Canadians have an IQ under 100. Most of this group will struggle to complete an academic program even given the strongest work ethic, personal discipline, and external support. This number is not going to change short of widespread genetic engineering...

Screen Shot 2015 08 07 at 8 16 45 PM

This cohort, about 40% of the human race, has experienced at least 40 years of declining income and shrinking employment opportunities. We no longer employ millions of clerks to file papers, or harvest crops, or dig ditches, or fill gas tanks or even assemble cars. That work has gone, some to other countries but most to automation. Those jobs aren’t coming back.

The future for about half of all Americans, and all humans, looks grim. When Trump talks to his white audience about immigrants taking jobs and betrayal by the elite he is starting a conversation we need to have. 

It doesn’t matter that Trump is a buffoon, or that restricting immigration won’t make any difference. It matters that the conversation is starting. After all, how far do you think anyone would get telling 40% of America that there is no place for them in current order because they’re not “smart” enough?

Yeah, not very far at all.

This is how democracy deals with hard conversations. It begins with yelling and ranting and blowhards. Eventually the conversation mutates. Painful thoughts become less painful. Facts are slowly accepted. Solutions begin to emerge.

Donald Trump is good for democracy, good for America, and good for the world.

See also

Thursday, July 23, 2015

Sleep disordered breathing Catch-22: sleeping with post-operative nasal obstruction and an unreliable oral airway

How would a cetacean live with a blocked blowhole? 

The question was asked in a 1986 newspaper column ...

A--Whales and dolphins breathe only through their blowholes, nostrils found on the tops of their heads, according to Daniel Odell, a professor of marine biology at the University of Miami. In the unlikely event that their blowholes are blocked or damaged, the animals would probably suffocate, Odell [1] said.

These animals have no connection between the esophagus and the larnyx, and breathing through the mouth is therefore impossible. While underwater, these animals seal their blowholes by means of powerful muscles.

I suspect Dr Odell actually said the cetacean would definitely suffocate; their anatomy means they are truly obligate nose breathers.[2][3]

Humans, in general, are better off. We aren’t obligate nose (blowhole) breathers, we can breathe through our nose and our mouth… 

Oops. I should have said adults can do that. Human infants are almost obligate nose breathers [4], if their nose obstructs they are desperately unhappy and cannot readily sleep [4]. But it’s not just infants, many human adults have great difficulty switching from nasal airways to oral routes when sleeping: "Several patients also had a greatly increased number and severity of episodes of nocturnal oxygen desaturation”.

Humans, it turns out, have a bit of dolphin in them [3]. Our nasal airways are a primary breathing system, our oral airway is a backup system and a turbo-charger for high rates of gas exchange (as in running). If we breathe predominantly through our mouths we experience dental and soft tissue problems. Our nasal airways have a lot of complex adaptation to manage the challenge of large volume gas exchange including autonomic control systems that shift air flow from one nostril to another [5] and “turbinates” (soft tissue mounds) that direct air flow [6].

Actually, I think of us as having 2.5 airways. We have the turbo-charger/emergency oral airway and we have two nostrils that shift air flow between them and act somewhat independently. But that’s just me.

Which brings me to … me. Yes, this is one of those tediously long individual medical anecdote blog posts. It’s my anecdote of managing sleep for seven days with a post-operatively obstructed blowhole (nose) and an unreliable oral airway. The Catch-22 is that the same conditions that made the surgery necessary also mad the post-surgical experience very difficult.

I’m hoping that this writeup will be useful for people in similar circumstances, and for their caregivers. It’s long enough that it has sections - thee first is your informed consent. The second covers what most physicians won’t know. The rest are for the inexplicably persistent.

Informed Consent

I don’t see patients, but I’m a physician and science-based medicine is one of my interests. Over the past few decades I’ve seen several rediscoveries of what we used to call evidence-based medicine. That’s the earnest (and important) attempt to reduce the number of times we hurt people by fervently recommending something that’s totally wrong. All of these programs come up with a grading system for medical knowledge, something like ...

Grade A: Recommendation backed by really well done randomized clinical trials. That’s how we know that Magnesium Sulfate is great post-MI [7] and every woman over 50 should be on estrogen for osteoporosis …(*cough*). Right. Even the best double-blind randomized controlled trial research isn’t terribly reliable. How we deal with that is a topic for a different blog post [8].

Grade B: Research trials and animal models that funky statistical massaging of big data sets that give us a good reason to try something relatively harmless (we think) or to fund better research.

Grade C: Expert opinion from the great gurus. The kind of opinion that gave us thalidomide for morning sickness and bed rest for back pain. AHA “911” guidelines are Grade C. Yeah, Grade C is moving into coin flip territory.

This blog post is grade D. Medical anecdote — which is more useful than I was once taught but is still very unreliable. I’m a family physician who designs clinical software — I haven’t seen a patient in 16 years. On the other hand, I have discovered that diseases have a differently look when seem from the inside instead of the outside. So there’s that. In any case, you have been warned.

Managing post-operative dual airway obstruction

Some adults are semi-obligate nose breathers when sleeping. If we can’t breathe through our noses we don’t breathe. We may accomplish a partial failover to the backup oral airway system, or we might awaken with pleasant dreams of suffocation (or we might die, but we don’t understand that very well). If we continue sleeping we may drop our oxygen levels below what our brain demands.

So what can we do? The usual prescriptions for sleep disordered breathing are weight loss [11] and CPAP. Since diet and exercise rarely produce significant weight lost the first of these usually requires costly and complex surgery. Nasal CPAP, assuming insurance companies would pay for it [10] would be working against a closed passage — that’s not going to go well. On the other hand oral CPAP is nasty (oral airway is second best, doesn’t have filtering and warming, etc) and, of course, there’s the obligate nose breathing problem.

There are other options (see the long version), but my particular nose was obstructed by deviated cartilage/septum on the left and by hypertrophied turbinates on the right — the legacy of anatomy, age, and allergies. I’d failed two years of intensive allergy therapy including twice daily Neti Pot irrigation “with (*cough*) sterile water”. So I opted for nasal septum reconstruction (I think it’s more than septum really, but I’m not a surgeon) and resection of the right medial turbinate. My results at this moment are excellent, but we know long term results may be often unsatisfactory for older adults.

in any case this post isn’t actually about whether nasal airway surgery is a good idea, or has lasting benefit, or the overlap between sleep disturbance and sleep apnea. It’s about how one somewhat obligate nose breather managed to get enough sleep to live [20] be semi-functional during the post-operative week where the nasal airway is shut down by blocked stents [14]. I used 3 devices, all of my own devising [18]. There was no insurance coverage for any of them, so the cost would be prohibitive for most Americans.

Device 1: CMS-50E OLED Fingertip Pulse Oximeter $74

I wanted an alarm to sound if and when I desaturated. Amazon has many low quality oximeters for under $100 , but most don’t have an alarm. The “CMS-50E” has both an alarm and the theoretical ability to export data to a CSV file. 

In practice it alarmed several times, but some of them appeared to be false alarms related either to software glitches or low power. I think there were one or two genuine desaturation events. It did reassure Emily and I that most of the time I seemed not be desaturating (she could read it while I slept). I taped it to my finger to keep it in place. It comes with an unreadable paper direction set, but it’s not hard to find a readable PDF version on the web. That does not mean one can understand the directions! Hint — there’s only a single button with two modes - quick press and long press. Long press is how one selects menu items. You have to set alarm threshold (default isn’t bad) and enable the alarm. I compared readings to a non-alarming $45 oximeter I’d bought earlier, they had similar readings. With correct finger placement the readings had at least “face validity”.

There’s a $250 device that uses a similar cheap probe, and lacks an alarm, but can do some data export: Masimo iSpO2 Pulse Oximeter (30 Pin Connector with Large Sensor for Apple iOS Device)

IMG 0003

Device 2: Maintaining oral airway patency by supine neck extension $3

Anesthesiologists know about keeping flaky oral airways open (which is a sign of how unreliable an isolated oral airway is, it often fails in sedated patients). They manually advance the lower jaw (mandible) — but that’s hard to do on one’s sleep self. They also place a roll just beneath the upper thoracic vertebrae (upper shoulder blade) to extend the neck. Since I suspect one reason that i’m an obligate nose breather is that my oral airway sucks (pun) [17] I used this both with and without a very flat pillow. I was completely unable to follow my surgeon’s recommendation to sleep in a semi-seated position - my oral airway collapsed within seconds of early sleep.

The straps kept it rolled up and I threaded them through a T-shirt to help hold the roll in position. I think it helped in the first few days post-operatively.

IMG 0002

Device 3: An oral prosthesis to force mouth breathing $300-$400 or more

This was the key, though none of the four quite good physicians I saw knew of it. Or if they knew of it they weren’t able to connect that knowledge to my problem. I came up with the idea and proposed it to my dentist, who told me I’d reinvented something well known to dentists: Oral Appliance Therapy (see also weirdly good wikipedia article on mandibular advancement splint).

The particular splint he created for me fit onto my lower teeth (fairly comfortably, he’s a good dentist). It separated my molars and had a frontal ridge that was supposed to catch my upper front incisors and thereby stabilize the lower jaw. Perhaps because my lower jaw is so wimpy [17] it didn’t seem to do very much, but the separation of my molars was just barely enough to overcome my natural disposition to clamp my jaw firmly shut when sleeping and help open a small passageway that, with much noise and struggle, I would breathe through while sleeping [19].

There are many designs for these mandibular advancement splints, I suspect there’s not a lot of knowledge about which work best for which people. This particular design just barely worked for me in the post-operative period and it wasn’t enough to let me skip the surgery. For some people a mandibular splint might provide enough support for a not-completely-obstructed nose to avoid surgery altogether.

IMG 0001

These 3 devices, but especially the mandibular advancement splint, let me sleep post-operatively.

This would be a good place to stop reading, because the longer version goes into more details on the post-operative course and the clinical presentation...

Post-operative course

The surgical procedure took about an hour. Afterwords I was fine. My nose was obstructed of course, but I never had any significant post-operative discomfort. That surprised me, I suspect a well done cocaine nerve block.

At night things got nasty. I’d already experienced two years of intermittent suffocation, and the first two nights did not disappoint. Sleep felt like wrestling with a mountain lion. The second night was the worst because i was also sleep deprived, the 3rd and 4th were not a lot better but I did get a few hours of sleep, and by the 5th and 6th night I was doing significantly better. I think the improvement was partly diminished drainage, and early my body adapting to oral airway breathing. According to my wife the breathing sounds were quite impressive.

I found it useful to count to 40 breaths through my mouth while wearing the mandibular prosthesis, the drill seemed to help my troubled transition to an oral airway.

in addition to the devices mentioned above it helped to drink a lot of fluids and to get out of bed every 60-90 minutes and clear as much drainage as possible without, of course, blowing the nose (that’s apparently disastrous, and it felt like a very bad idea). If you were ever a 9 yo boy you probably remember how to maximize spitting distance. The same noisy and revolting technique applies. This especially worked after day 3 when the big dark clots come out.

I used the Neti pot nightly as my surgeon recommended. It didn’t contribute much as my nose was adamantly blocked, but I think it reduced discomfort related to dry clot.

For the first 4-5 days I wore a “mustache dressing” below the nose; contrary to the way it was taught me I found folding a 3” gauze into 3rd worked better than half. It has to be worn with minimal pressure or the tissue around the nose gets sore. I administered vaseline before applying.

Although I had no pain hydrocodone pain meds helped with sleep, probably because they make it easier to tolerate discomfort and perhaps because they make suffocation more tolerable.

Air conditioning was helpful too, I don’t know why. 

The stent removal didn’t bother me in the least. I was immediately able to breathe very well by nose. The Neti post was very helpful for the 3-4 days post stent removal, I used it twice a day. I resumed my antihistamine allergy spray post-stent removal but held off on steroid spray for one week. I then returned to a reduced version of my allergy regimen.

There were 7 medication related physician errors with my post-operative period. None of them caused any harm; they provided some light amusement for Emily (also a family physician) and I. Still, not great. 

The presentation 

I’m going to finish this up with a part that might be of interest to physicians. Namely, how did I first present with this problem. In brief, weirdly.

Two years ago, while on vacation in Florida after a long drive, I awoke at 2am sweating, breathing deeply and rapidly, with my heart pounding. It felt like a sleep terror, but I was about 40 years too old for those. My initial thoughts were about where best to leave my corpse given that the kids were in the room. I assumed i was having a major cardiac event, a new rhythm disorder (most likely), or a likely fatal pulmonary embolus (my mother had recurrent PE). On the bright side, maybe some degenerative neurologic disorder was manifesting as late onset panic attacks or a new variant of my adolescent sleep paralysis.

It never occurred to me that my airway had completely obstructed. In all my (admittedly dated) reading of sleep apnea I hadn’t read of such an acute onset. (Which may be another example of the fundamental problem with medical disease descriptions.)

Over a few minutes everything settled down. I felt fine, if somewhat anxious. Which didn’t fit most of my diagnoses, save perhaps the neuropsychiatric. At this time many physicians would have sent me to the ED, but for various reasons this would have been unusually difficult for my family. So I went back to bed. 

The problem recurred intermittently over the next few weeks, generally in a milder form. Then, on return home, it resolved. Until a couple of months later when it recurred and was associated with a sensation of “air hunger” (not getting enough air on deep breathing). So, after a bit of dithering, I went for my pulmonary embolus evaluation. Which, to the great surprise of both the ED doc and my wife and I, was negative. EKG was fine too, not to mention that I was into regular CrossFit by then. i’d be dead if I had a cardiac problem.

It was after ruling out the obvious causes, and having more regular recurrences, that I figured out that I was awakening due to asphyxiation. My nose, which had been gradually getting less functional over 30+ years, would completely obstruct, and I would fail to activate my backup oral airway. Which is, to be frank, quite weird. It took me a while to figure that out because I didn’t think it was possible. I suspect a non-physician would have made the diagnosis months before.

After we knew what was going on I did see an ENT and I attempted (but failed) to meet up with a sleep specialist [22]. I then embarked on my family doc's recommendation of Neti pots and maximal medical therapy — in part because of my research showing uncertain long term value of nasal surgery and in part because medical types don’t trust surgeons. I got to maximal medical therapy after an allergist visit, and when that failed I opted for surgery. It was during the two years of medical therapy that I came up with my approach to the post-operative period. 

- fn - (lots)

[1] Dr Odell joined SeaWorld in 2001. I assume he’s retired by now, but hope he’s doing well. The web gives us odd glances into people’s lives.

[2] So how do cetaceans produce sounds you ask? Well, that’s where things get weird and fascinating — too odd to put into a blog post. Cetaceans have sets of laryngeal air sacs that may, or may not, be analogous to our (useless?) paranasal sinuses. So one theory is they vocalize like a Scottish bagpipe (used as a comic illustration in that article). The best article I found was a fine post in a flaky sounding blog; turns out there’s a surprising amount of uncertainty. The article doesn’t explain why captive dolphins open their mouths when demonstrating sound production in air.

[3] The fact that an aquatic mammal can evolve to segregate oral and nasal airways does put an interesting spin on human obstructive sleep apnea. We are notoriously good swimmers for a land animal. Alternatively, we also are notoriously good at producing complex sounds, that ability might also have required some compromise of our airway systems. Natural selection would not produce a compromised airway system without a powerful adaptive advantage [4]...

[4] Are infant chimpanzees obligated nose breathers? It would be fascinating if they were not.

[5] Many people notice that one nostril or another is dominant at different times, including variations with head position. This isn’t a random thing, it’s a control system that, we assume, enables tissue rest and recovery.

[6] Years ago surgeons managed some kinds of nasal airway problems by removing the turbinates. This worked well at first, but then patients developed “Empty Nose Syndrome”. Which, of course, we don’t really understand. The neurophysiology of nasal breathing is complex. Incidentally, the nose is much bigger than you think.

[7] Nobody but me will remember the @1992 Mag Sulfate post-MI study that made it into the textbooks but then was reversed by an even bigger study. At that time I was a keen young physician teaching curmudgeonly old braindead docs to use “Grateful Med”, with slides (real slides, or transparencies, prepared using Symantec’s MORE 3.1). I used the then obligatory graph describing the volume of medical knowledge and bemoaning the backwardness of physicians who didn’t read the latest journals. 

That one small reversal shattered my faith. That was when I looked at 10 year old journals and saw how few of the “best” recommendations survived. I proposed, but never pursued, writing an article that tested the non-evidence-based idea that one should read medical journals. Thankfully others were more persistent than I and made a fine academic career of looking at the lifespan of grade A research results. I no longer see articles bemoaning physician failure to track the latest fads.

[8] Ok. The usual answer is meta-analysis. I think we need to look at predictive Bayesian models. So combinations of human clinical trials plus animal models plus biology … Yeah. Needs a separate blog post.

[9] Brains and hearts are the oxygen fiends. Presumably desaturation happens a lot more in Denver than in St Paul MN, but I haven’t seen much discussion of that.

[10] CPAP seems (do we have 15 year natural history studies?) to work well for sleep apnea and sleep disordered breathing - at least for people with working noses who can tolerate it. For reasons I don’t fully understand (expense of evaluation? expense of device/use?) insurance companies are reluctant to pay for it even as demand seems to be rising. So there’s now a big complex hassle around sleep disturbance evaluation, apnea diagnosis, and CPAP use. But this blog post isn’t about apnea ...

[11] FWIW if I got skinnier my wife would send me to an eating disorder program. 

[12] What messes up the septum? Mine was deviated in childhood. The usual explanation is trauma, but I also have a developmental anomaly of my chest wall. So I wonder more about a developmental growth disorder. The allergies are a lifelong nuisance. My surgeon claims that it’s common to see hypertrophy of turbinates on the unobstructed side — presumably due to some mix of missing feedback, increased work, allergies, etc.

[13] Yeah, nasty brain eating protozoan. I probably should have paid to install a filtration system at home and just take my chances when traveling, but I just used tap water.

[14] My surgeon didn’t use old style packing, but “stents” have to placed to stabilize the septum. In my case they were removed one week post-operatively. In theory they are designed to allow air flow, but in practice they always obstruct immediately and cannot be cleared. Material used to reduce bleeding likely contributes to obstruction.

[15] CSV export requires use of a flaky Windows app I’d want to run through a first class malware scanner. I didn’t bother trying to configure it on my Mac VM.

[16] All sold only for “exercise monitoring”, not for medical use. Almost all the reviews are for medical use.

[17] I have the classic small weak puny jaw of the pencil neck geek. I was amazed by the quality of wikipedia articles related to airway problems — maybe there’s a small-jawed-geek-airway-syndrome to be discovered? Something related to maternal testosterone levels perhaps ...

[18] None of these were invented by me of course! I mean that I thought of them in the two years of dreading post-operative asphyxiation. If I had thought to read wikipedia instead of medical articles I’d have learned about the oral prosthesis immediately, instead of having to reinvent it and find my dentist made them. None of the four quite good physicians (and one inexperienced sleep specialist PA [22]) involved in my care, including one family physician, two ENT physicians and one allergist had anything useful to contribute to this particular problem. I think it’s a problem that falls into the black holes between medical specialties, and particularly between medicine and dentistry. Which is appalling, but not surprising. I’d be no better save that I had to solve this problem. The medical literature sucks. Which is why, of course, I spent hours on this blog post.

[19] So why do I firmly clamp my jaw shut while sleeping? I don’t know. My theory is that I have an anatomicaly lousy oral airway, and that I learned to clamp my jaw shut at night to stabilize it and allow nasal breathing before my nasal airway failed. I needed to undo that reflex to get through the post-operative period.

[20] I thought we couldn’t go more than 4-5 days without psychosis or serious health issues. i just now learned that’s wrong — in 1965 Randy Gardner, a 17yo madman, went 11 days for a science fair project. He seems to have subsequently led a fairly quiet life. He had a cat in 2006. So maybe I could have dosed up on modafinil and made a run for 7 days.

[21] Neti pots are one of those weird devices that seem perfectly hideous and revolting on first use but become relatively familiar and appreciated. It’s worth pushing through the initial ickiness to be able to use them for colds and allergies in place of medications. Just watch for the brain eating amoeba [13].

[22] The sleep specialist evaluation was a classic 2015 American medical fiasco. I ended up seeing a brand new (inexperienced) PA who recognized I didn’t fit the obese-apnea pattern they saw 40 times a day and didn’t really know how to proceed given my nasal obstruction and the expectation that I’d have disrupted sleep rather than sleep apnea. The roots of this mess-up had to do with all of the protocols sleep specialists and insurance companies have put in place in their CPAP revenue battles, a recent corporate acquisition of the practice, a problematic transition from sleep center to home sleep studies, and a disruptive electronic health record transition. This was my only medical-bust of the evaluation.

See also

Tuesday, July 21, 2015

Counterfeit bicycle components and my defective "Shimano" pedals

Today the NYT reported on a flood of “counterfeit” bike parts out of China. The parentheses are there because the article mixes up true counterfeits with diverted goods from “genuine” part assembly lines. Carbon fiber frames and wheels are probably the biggest problem — they’re very expensive and it’s pretty much impossible to distinguish a high quality carbon frame from a decent counterfeit that uses low grade materials (welcome to catastrophic frame failure at velocity).

As one would expect eBay and Craigslist are full of these things; surprisingly one cyclist friend is quite satisfied with the quality of the counterfeits he knowing buys. Of course not everyone knows they’re buying counterfeit goods, especially when items are sold at the genuine list price.

Which reminds me of my Shimano Pd-Mx80 Platform Pedals. I bought them from Amazon … sort of. In reality, from “Amazon marketplace” and “4ucycling”. 

Yeah, Amazon marketplace, home of zillions of worthless counterfeit “Apple” iPhone cables.

Did I mention one pedal started making hideous cracking noises the third time I used it? The pedal core spindle is binding on the casing. Here’s what “4ucycling" wrote when I asked about after-sale service:

hello dear:
you can contat with your local Shimano distributor,thanks.
regards

Hmmm. They came in a nice box with normal Shimano directions, so maybe I just got unlucky. Or maybe they’re Shimano parts that failed quality control, and got diverted from the scrap room. I might try contacting Shimano just to find out.

I think that’s the last bicycle item I order from a no-name “Amazon Marketplace” store. I’d never do that with any electronic devices, but somehow my radar failed me on this one. Maybe I'll try a Crank Brothers 5050, sold by Amazon (not the marketplace).

Caveat emptor.

Tuesday, July 14, 2015

How to donate used bikes (and why that may beat selling them)

In the Twin Cities we have a number of places that accept bike donations, fix them up, and sell them. They use the money to fund community activities and provide selected donations.

if you’re fortunate enough to be in a high tax bracket, the deduction may be competitive with what you’d get selling the 2nd hand bike to a local shop. You’d get more if you could find a direct buyer, but that’s work. Second hand bike shops don’t offer much for a used bike, though they sell them for more than I’d expect.

If you do donate you need to know the $250 (single transaction) and $500 (yearly total rules). If you are over $250 you need a record of the donation; the shop provides that, along with proof of tax status - so that’s no problem. (No point in trying to split donations.) If you are over $500 for the year (easy to do) you need to complete Form 8283 so you’ll need records for EACH donated item of:

  1. Donee organization
  2. Property description
  3. Date contribution
  4. Date acquisition and how it was acquired (getting harder!)
  5. Cost at time of acquisition
  6. Fair Market value at time of donation  and method used to determine (recipient can’t help, I compared items to price of similar items on sale and used that value).

Yes, bit of a pain if you don’t know ahead of time. I use a Google Sheet to enter data, print it out, stick receipt on it, then toss it in the box.

Sunday, July 12, 2015

Tools: emulating (Rally) Agile work using Appigo ToDo.app and ToDo Cloud

My circumstances have changed. I may have more to say on that later; even in the sort term it is probably a change for the better. But of course life must be lived forward and understood backwards and all that.

One of the benefits of my new position is an opportunity to revisit my Tools. At one time (less so now) I’d read that tools didn’t matter, it was all about … something. Process maybe, or magic. This was sometimes used to justify a lack of investment in tools to support getting work done. I won’t bother refuting this idea, it’s self-evidently wrong.

Tool choices shape everything. I like Tools that last years to decades; switching costs are often high [10]. In practice, since modern software has very short lifespans, this means choosing adaptable tools and, when data lifespan is longer than tool life expectancy, portable data. For a serious Tool complexity and learning curve don’t bother me, but complexity shortens already too short software lifespans and and usually binds a Tool to a single platform (web typically). So I reluctantly favor simplicity - just enough functionality to do what I need. (I despise the current fashion for early delivery of barely working products, but that’s another story.)

These past few days I’ve been choosing my go-forward task and project management tool. Over the past few years I’ve used a mixture of Google/Outlook Calendars (don't underestimate the power of the Calendar), Appigo ToDo.app for iOS with sync to Toodledo for web access and data freedom, and RallyDev’s “Rally” Agile project/task management software.

I could write a book on the RallyAgile (which is Agile shaped by Rally) and the twisted evolution of that tortured product. It is hard to watch software adolescence — the drinking, the reckless driving, the law breakin … then, if one is lucky, the emergence of a somewhat broken product that may do some good in the world.

Suffice to say there are things I liked about the way I adapted RallyAgile, such as Features that are completed in 3-10 weeks of work, Feature-Stories that map to 1-10 days of work, and Feature-Story-Tasks that map to 1-6 hours of work. I sized “Stories” [1] by “Points” where a “Point” is 5 hours of work [2], and where a Story could be any one of 1, 3, 5, 8, 13, 20 Points [3]. I liked two week iterations [4] as a practical planning unit - a period where each task was (tentatively) assigned Calendar blocks and where one could focus on getting Stories complete rather than constantly replanning. I liked having protected time for planning a “Release” (set of Features basically) and for planning an “Iteration” (2-3 week collection of Stories), time to review and improve process, and time to look ahead and reassess “Features” and “Release”.

Today I’ve made my first pass at a set of Tools (and, yes, practices) that will give me the functionality I want within the constraints [5] of time, budget, familiarity, platform (Mac/web) and the requirements of longevity. In bullet form, here’s my list:

  • Google Calendar: Well, I’m certainly not going to use anything Apple owns [6], and Outlook is owned by ZombieSoft. So pretty much narrows that down.
  • Appigo ToDo and ToDo Cloud: I never seriously considered Rally. Omni products are too platform specific and I fear lifespan. My use of Toodledo was a path-dependency accident of history, and now that Appigo has fixed task-creation-by-email I can switch fully. Primary downside is data lock [7]. My next option would have been Trello, but there’s no native Mac client, I don’t need distributed team support, it’s complex, the nomenclature is odd, etc. [8]
Here’s how I map “Agile” style of “getting things done” [9] to Appigo ToDo
  • Tasks -> Tasks. (Tasks are are tied to projects may get Stars, not sure if I need to do that)
  • Stories -> Projects
  • Features -> List Name (Contexts and Tags will take on some of the things I use List Names for).
I think I’ll put “hours” and “points” into the Titles of Tasks and Stories.
 
The relation of “Features” to bigger Goals/Initiatives/etc I plan to map out in MindNode.app, but that’s another post.

Tasks associated with “Stories” get slots on the Calendar. I will still use Appigo ToDo for tasks unrelated to “Features”/“Projects”, those have the usual ABC priority (simplified from old Franklin/GTD priorities) which work like this:

  • A/High: Get Due Date and time on calendar
  • B/Medium: May get a due date, may have calendar time
  • C/Low: No due date, no calendar
I’ll update this post in future as I fill in the rough spots.

- fn -

[1] Without going into details on my own twisted adaptation of Agile, I dislike the word “Story” and all of it’s subject-action baggage. I use “Story” to mean a testable unit of work that is composed of tasks, is measured in “points” where a “point” is 5 hours of real work, and may be part of a “Feature” (which is, etc).

[2] Ok, one more detail. The mysticism about the meaning of a “Story” "Point” also annoys.

[3] Fibonacci more or less, where as Points go up so does uncertainty. I was the best Estimator I know of — I’d do my initial Story estimates, decompose to Tasks and assign hours to tasks, sum the hours and divide by 5, then round up to next Fibonacci number (so 11 hours is 3 points). When I did Task estimates I assumed an average rather than ideal path, and adjusted for dependencies — esp. on unreliable corporate infrastructure.

[4] In practice this was too much planning overhead with distributed teams; 3 weeks is better in that case. I like 2 weeks for local teams. I could write another book on doing corporate software development with distributed teams.

[5] Ahh, Constraints. So important to choice, thus project planning. Could write a book about those too :-). Constraints are my friend, a relative of Requirements I suppose.

[6] Has any company ever killed more data, data formats, products and platforms? Apple is a charming TV sociopath serial-killer of a company.

[7] App.net.@clarkgoble tells me there’s a SQLite database and Todo Cloud data is CalDAV and theoretically extractable, though I suspect much would be lost. There’s also the back door of switching back to Toodledo and their export features, but that’s a cheat. I wish Toodledo had implemented full-text search, but I understand my task volume and complexity is not their market.

[8] I’m keeping on eye on Trello. Familiarity and time were constraints too.

[9] Yeah, GTD and all kinds of old Franklin stuff on goals, etc all fit in here, but that’s yet another book.

[10] In writing this post I reviewed past blog posts. It wasn’t too hard to switch from Franklin Planner paper to the PalmOS in the 90s, but the 00s switch from PalmOS productivity Tools to early iOS was brutal. Awful. Horrible. MobileMe… argggggghhh. It went on for years, no thanks to Apple [6] but sincere thanks to pre-Evil Google. The pain of that switch is one reason I’m reluctant to commit to anything novel - like Trello.

See also

Sunday, July 05, 2015

Why don't we have better medical textbook descriptions of disease?

I have a problem with the way medicine describes diseases. It’s not a new problem - it’s bugged me since about my third year of medical school - 1985 that is. I don’t think things have changed much.

To describe my problem, I’ll invent a disease “Y”.  Y has 3 findings - flat feet, pimples, and bad breath. Each occurs in 1/3 of the people suffering from Y.

What’s the probability that someone has flat feet and pimples given that they have Y?

No, it’s not 1/9.

I never said these were independent findings, and I never said they persist. Y starts with flat feet, then is asymptomatic, then patients develop bad breath and pimples. Yvians never have both flat feet and pimples at the same time. The old multiplication rule only works for independent events.

Ok, so you saw this one coming. Obvious, isn’t it? Well, yes, but most textbooks describe diseases as though they were collections of independent events without correlation or sequence or evolution or treatment effects. They provide long lists of symptoms, some of which rarely or ever coexist, followed by lists of findings, tests and so on. They very rarely, almost never, describe the long term sequelae of common acute conditions. (Often that’s because nobody has researched the “natural history” of the disorder. So the section would have to read “we have no idea” most of the time. That would be a start though.)

At the end of reading a classic textbook disease description you might be able to pass your Board exam, but you really have very little idea what the disease looks like, much less how it’s experienced by the patient. Sure, you learn that stuff after 5-10 years of patient care — but, really, that’s nuts.

Another way to learn this is to experience disease first hand - especially if you’re a 50+ physician. My own (one time) 1-2 day episode of vertigo didn’t match the textbook description of acute labyrinthitis or benign positional vertigo — it had features of both. It also left me with a subtle and persistent degradation of my balance - that doesn’t show up in textbooks either. Every 50+ physician can probably tell a similar story - our textbook descriptions of disease are misleading, incomplete, and frustrating.

I don’t think it was always this way. I have a 1930 edition of William Osler’s ‘The Principles and Practice of Medicine’ on my desk, what that book called “symptoms” was more the course of a disease. I wonder if the 19th century editions were even more case based.

We could fix this, but I never see anyone talking about it. We’d have to first admit we had a problem.

The American Heart Associations "911" heart attack campaign is not evidence based

My friend Jim Levin died a couple of years ago; he had an MI running for a plane. Shortly after his death I visited the American Hearth Association's warning signs of a “heart attack”. I wasn’t impressed. What active 55yo doesn’t have chest discomfort 20 minutes into a killer CrossFit workout? Short of breath? Yeah, a bit.

So I made my own list, based on nothing but my native ignorance ...

  • If these things occur together it's more likely to be heart disease. So shortness of breath AND "cold sweat" [2] AND jaw discomfort all together means more than one of them by itself.
  • It's one thing to feel short of breath when you're a healthy person running a 5 mile race, another if you are short of breath doing stuff that is normally easy (like watching TV).
  • If symptoms like "arm discomfort" and " nausea" come on with exercise and get better with rest -- that's ominous. (Exercise means the heart needs more oxygen, so it can expose an underlying problem.)
  • If your parents died of heart disease in their 40s and your LDL cholesterol is 250 and you smoke and you're male ... Ok. You get the point. Most of us have some heart disease by age 50, but some people have a lot. Weird pains at rest may not mean too much in a low risk 30 yo woman but in a "high risk" person they might be bad news.

Today I again thought of the AHA’s non-specific warning sign list. I thought maybe things had improved, so I went looking for a publication that describes the predictive value, or even sensitivity and specificity, of the AHA’s heart attack classification criteria. After all, we communicate the AHA list to hundreds of millions of people. There’s gotta be some science behind it … right ...

I found two interesting references, one predating my 2013 blog post

The 2014 study was limited to patients who were actually in the ED. The 2008 study was broader and concluded: "there were almost no included studies that investigated the diagnostic accuracy of combinations of signs and symptoms …it was not possible to define an important role for signs and symptoms in the diagnosis of acute myocardial infarction or acute coronary syndrome”.

Dear AHA — this is ridiculous. I suspect if everyone took your 911 signs seriously ERs would be overwhelmed with “rule out MI”. You need to come up with an evidence-based symptom list.

Friday, July 03, 2015

Perspective - 20 year family reunion probabilities

For at least two good reasons I’ve been doing a bit of planning. More on those reasons later, but first a digression to answer a relevant question.

What is the probability that, estrangement aside, our nuclear family will be able to do a reunion in 20 years? Let’s assume for simplicity’s sake, no major disruption of civilization and no major changes in US mortality rates by age. I’ll also exclude Kateva, who is healthy at age 10 but unlikely to break canine longevity records.

It’s not hard to do the rough calculations, unadjusted for gender, wealth, education or health, using a basic Life table. I'm looking for 

tPx: probability someone aged x will survive for t more years.

and the formula based on a Life Table is:

Lx+t/Lx where Lx is the number surviving to age x

Lx can be found in the US 2010 Life Table. (Excel version can be downloaded from: ftp://ftp.cdc.gov/pub/Health_Statistics/NCHS/Publications/NVSR/63_07/Table01.xlsx)

For my family the relevant values are:

Living

Which gives survival probabilities for 20 years beyond current age as:

Screen Shot 2015 07 03 at 2 05 26 PM

Where Product All is the product of each more-or-less independent probability. That is only about 50%, which is not so great. On the other hand, in the event of the cosmic calamity of my demise, I won't have much skin in the game. So the interesting number is the probability that Emily and kids make it assuming I do, which is Product “Impt” (important). That’s 71%.

Which is a useful number for my planning purposes and that future post I promised.

PS. I can remember when 20 years felt like a long time. It’s not.

Thursday, July 02, 2015

Apple TV's PBS station has great shows, but an awful user experience

Anthro prof John Hawks, one of my favorite bloggers, is hosting a sure-to-be-good PBS series called First Peoples. You can stream the (ugh) Flash (ugh) version … too bad it’s not on Apple TV….

Except … it is. It’s just bloody hard to find. The PBS Channel Search menu searches only “Videos”, not “Shows”. To find Shows you have to scroll around … and around … and around… the “Shows” screen. Good luck with that. Once you find a show you can add it to Favorites.

I don’t know if this is something PBS can fix or if it’s some sort of Apple malfunction, but … wow … needs a fix. At the least Search needs to include Shows.