The Ether Way

postoperative visual loss (POVL)

POVL is vanishingly rare but when it happens its a nightmare on (insert your hospital's street) street.
It occurs typically during prone surgery even when pins are applied and there is clearly no eyeball pressure.
Opth exam shows ischemia of either the retina or the nerve.  predisposing factors include long case, hypotension, bleeding.  notably with longer cases intraocular pressure has been noted to rise.   I have always hunched that it was somehow related to high venous pressure too.  One clue for this was a patient of a colleagues from a few yrs back during thoracic vertebral surgery from an anterior approach they got into bleeding and had to occlude the svc to stop the bleeding. after all the face swelling finally subsided the patient was quite blind with not even light perception.  similarly cavernous carotid fistuas also produce blindness.
So based on the above physiologic considerations for prone cases my approach is to give just enough anesthesthetic to ensure unconsciousness and if that makes the MAP go less than 80 mmHg i run dilute neosynephrine to make it so.  Use bis and keep it at 55.  transfuse to Hb 10.

the path to new knowledge

Experience is good, science is extolled.  are they mutually exclusive?  Is the scientific method the only path to knowledge.  Is a randomized controlled trial really needed for everything?  Can the effect be so robust based on historical "experience" as to obviate the need for a randomized trial.  I think the discovery of penicillin was in this category.  before most people died, and afterwards most lived.  Is EBM over rated or maybe it needs to be used appropriately and selectively:

Download parachute.bmp
from http://www.auahq.org/Summer2005.pdf

(click on pic to see big version)

So now we have the budget meisters, in the name of quality and safety, refusing requests from experienced clinicians for expensive new therapies.  I requested dexmedetomidine from the UPenn P&T committee with use restricted to neuro patients.  It has some qualities that seem perfect for this group, like producing a sedative state with easy arousability to do a neuro check.  sorry....no rct's on dex for that purpose.    Also, too expensive.    doesn't much matter that there's not an RCT for the use of say, desflurane or sevo for cerebral aneurysm surgery, or even for a  TURP......   

Experience

    Good Outcomes are the product of experience.  Experience is the product of bad outcomes.  That's how I learned the dictum and it's still how I repeat it.

    Patient safety has been a real interest of mine - both academic and professional - for over a decade. Safety and quality are confused and conflated in the minds of physicians, academics, health care management, government regulators, and the lay press.  Safety is about avoiding accidents and disasters from the routine delivery of healthcare; quality is about producing the best possible outcomes with the resources at your command.  There are very few people who have substantial understanding of safety in healthcare, and there cannot be anybody who has a complete understanding. 
    Bad outcomes? They're statistically measurable, you may not be able to predict which patients will have them, but if you find a group large enough, you'll be able to predict the rate of these outcomes with great precision. Examples? Death, stroke, and renal failure after cardiac surgery, catheter related blood stream infections, and urosepsis from bladder catheters are a few.  Quality might be about reducing the incidence or severity of post-operative nausea and vomiting, a relatively common problem.  Safety is about extremely rare events - chemotherapy overdose, wrong side surgery, and such.
    I'm a questions guy, not an answers guy.  If you want answers, find someone else.  Experience has taught me that finding and framing the question in many topics is extremely difficult, and constitutes a substantial portion of the real intellectual work.  Experience and the literature - basic science and clinical(applied) - inform but almost never 'answer' questions.  People who have a deep understanding of any topic appreciate this.  As group, they make poor television and newspaper interviews. 
    Like Mitch, I highly value experience.  Much of the story of medicine for the past 15 years has been about the systematic devaluation of experience.  Where muddy tales of experience have been supplanted or complemented by high quality clinical studies, this has not been a problem.  Where precious experience has been displaced by shoddy clinical science and 'expert' opinion....... the effect may even have be deleterious.  In his post, Mitch has pointed out that the world of medicine accords too much respect to weak studies.  I concur. The meaning of studies is far less evident to those with experience than those without (or with political or economic agendas).  There are numerous instances where very similar studies of the same problem have produced contradictory results.  How should we proceed? That would be a suitable subject for a book, or perhaps another post in the future.  Suffice it to say, that practitioners fall back upon either their bias or their experience when sifting through the literature.
    The centerpiece of experience is time in the trenches.  There is no substitute.  With that time comes both the glory of great saves and the heartbreak of failures.  As practitioners and communities, we measure everything we think we know and understand by how it maps with our own experience.  Everyone with substantial experience has substantial experience with bad outcomes.  Compassionate practitioners think about their failures and learn everything they can from them.  The learning (individual and collective) may be the only good that comes from these events.  Bad outcomes have a real impact on practitioners, who can sometimes become secondary casualties of these disasters.  If we expunged everyone associated with bad outcomes from medicine, there would be no one left to provide care for our patients.  My claim is this: our failures of yesterday empower us to produce our successes of today. 

Good Judgement Comes from Experience...

Early in my private practice career, I had an old partner who did outrageous things. Monitors? Maybe. I'd give him relief, and shudder at what I found for vital signs when I hooked the patient up. He didn't bother much with preo-op interviews; he'd just look at patients in the OR while he was drawing up the pentothal and sux. I'd tut tut to myself, having just come from my University Post where I had played the role of encyclopedia anesthetica for my department; you know, the guy that knows all the literature and (in those days) kept multiple file drawers full of carefully catalogued articles. All departments have a guy like that. Since I had been almost immediately placed on the local QA committee, I self-righteously waited for the ineveitable consequences of his apparent inattention. There was only one hitch.

He never got in trouble. Not once. I practiced with him for years, and never once had a case fall out in QA. Oh yeah; he chipped a patient's tooth once, and as was the custom back then, he bought the patient a crown. End of story.

Now this was a guy who had given anesthetics for pediatric cardiac surgery in the era when perfusion consisted of hooking up baby to mom's iliacs and using mom as the heart-lung machine. That was long before pulse oximeters and gas monitors (think about doing a pediatric heart case without a pulse ox!) In the era "when ships were wood and men were steel," I guess he was a bosun. Towards the end of his career, I asked him why he never got in trouble. He thought for a while, then said something like, "well, I just look at 'em,  and if it looks like I can't kill 'em, I just put them to sleep." Enigmatic.

Back in training, we all did a rotation with a group of private practice guys in a community hospital. One day we were doing a case; a lumbar laminectomy or the like, and as a conversation starter, I told my attending about some or another study I had found in Anesthesiology the night before on aspects of just such a case. He asked me how many patients in the study and I told him, whereupon he kindly informed me that by his reckoning, he had done at least three times that many in his twenty years of practice. End of conversation.

It's now twenty five years later, and I still reflect on that day. By my own reckoning, I've done North of 20000 cases, at least 18000 of them myself, not supervising.

I understand those men a lot better now than I did at the time. I still do a careful preop evaluation, but it's a lot different than it was; like Bob Seger said, I know "what to leave in, what to leave out."

I figured out Swan Ganz catheters weren't generally doing my patients a whole lot of good long before the Canadian study demonstrated that. It's too bad because they were a lot of fun.

I still read the literature, but not with the same rapture I had opening my journal each month when I was a pup. A lot of the time, what I read doesn't pass the "sniff test" of more than two decades of practice. For instance, perioperative MI's. Pretty darn rare out here in practice land. Maybe that's because triple-A cross-clamp times are typically about 15 minutes. I just don't know.

Occasionally, though, there'll be something that makes me say to myself, "now why didn"t I see that?" or, as often, "I knew that." Those are thrilling moments in the dry business of literature reading,  and like the straight 300 yard drive in golf, (I am a psycho-motor nincompoop) the intermittent irregular positive reinforcement is a strong behavioral stimulus to keep reading.

I like messy review articles, and airy-fairy stuff. A couple of years back, there was a review article in Anesthesiology on Cardiopulmonary bypass and SIRS: fun! And Hameroff's latest Article on Anesthesia and Consciousness. Cool.

I'm pretty sure that my continued interest in the anesthesia literature doesn't directly translate into lives saved and morbidity averted; my best partners, and the guys I would let anesthetize my kids aren't big anesthesia readers, but they're great clinicians.

On the other hand, I find that general medical knowledge is pretty handy to have around the OR. And, with the scarcity of internists these days, general medical knowledge is getting to be distressingly rare; it's increasingly a do-it-yourself world.

Oh yes, the title of this post comes from a saying attributed to a long retired partner of my practice, gone before I got here twenty years ago. By some reports, it was first said by Will Rogers. Good judgment comes from experience, and experience comes from bad judgment.