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Myths,Models,Paradigms(Whatyouthinkyouknow

thatjustain’tso)

ThomasBenzoni,DO,AOBEM,FACEPApril19,2016@1100

IPAS

Recitals

•  Agency • None

•  COI • None

•  FDA • Likely off label

•  Rules of engagement • Adult conversation

Objectives

•  Examine common misperceptions. •  Slay sacred cows.

• They make the best burgers! •  Learn how to look for external validity. •  Become a skeptic, esp. about research.

• Not a cynic

Order of the day

•  Bring up a common belief. •  Dissect it. •  Discuss it. •  Bury it.

•  Rinse, lather, repeat.

Why is this important?

Your patient Will not get better On your therapy For a disease

Which they don’t have! (Myths support sloppy thinking.)

Feynman

It doesn’t matter how beautiful your theory is, it doesn’t matter

how smart you are. If it doesn’t agree with experiment

(observation), it’s wrong.

(This guy built the atomic bomb.)

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hPps://s3.amazonaws.com/wbstaVcfiles/users/449/209191_myths-and-legends.jpg

Let’s start with CPR

•  Identify the problem, a good first step • The greatest trump card in the treatment of

the disease is the diagnosis - Voltaire

•  Establish pulselessness • Treat it. (Get on the chest.) • All else is vanity, a distraction.

• Only chest compressions have been shown to work! (Except shocks with shockable rhythm; same logic.)

Let’s start with CPR

•  How about bicarb? •  Henderson-Hasselbach equation

• (Wgt * base deficit) * 0.6 = (x)mEq • (x)/50 = amps NaHCO3

• We were giving 10 – 15 amps! •  PVC’s: >6/min = treat

• CAST trial (1991): increased mortality

Whywerewesoeasilymislead?

http://chainreactionblogs.com/diary/wp-content/uploads/2013/11/IMG_6469tiger.jpg

ItseemedlikeagoodideaattheVme.

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Epinephrine

•  Use in cardiac arrest • Regular dose: no advantage

• Epi is likely going out of ACLS. • High dose: seemed like a good idea at the time

• Recurring theme…

• Remember vasopressin?

Speaking of Epinephrine •  No epi fingers/nose/penis/toes

l  Epipensareinjectedintofingers(0.3mg=30cc1:100,000)withoutconsequence

-  hPp://www.ncbi.nlm.nih.gov/pmc/arVcles/PMC2526033/

l  Sowheredidthiscomefrom? l  (LearntosourcearVcles.) l  1884cocaineusedfordigitalanestheVc l  1927firstreportedcaseofnecrosis l  1944Burnellstatedvasoconstrictorsshouldnotbeusedwithend

arteries;we'reofftotheraces. -  Doesismakeadifferencethatlidocainewasinventedin1948?

EpimustbesenVentforourmodelstobecorrect.

So how about oxygen? •  Default application by EMS

• Protocols dictates SaO2 < 94% •  Hyperoxygenation increases MI size

http://www.patientsafetysolutions.com/docs/February_2012_More_Evidence_of_Harm_from_Oxygen.htm

•  No benefits from hyperbaric oxygen in wound healing

http://www.medscape.com/viewarticle/857418

•  Can we arrive at the same conclusion by thought?

Pinkeye •  Can’t go back to day care without drops!!

l  (AssumpVon:youcandiagnosecorrectly.)l  Viral,allergic,chemical,traumaVc,bacterial l  Wheredidthiscomefrom?

l  Probablyextensionofophthalmianeonatorum So:

WhyperpetuatenuclearoriginofconjuncVviVs?(Whenignoranceisinvincible,treatsymptoms) Rx:Lacrilube™areeyedrops. http://www.clinicaladvisor.com/the-waiting-room/identifying-the-

differences-of-viral-bacterial-allergic-conjunctivitis/article/488241/

Treating corneal abrasions

o  No evidence to support patching o  Plenty of evidence against use

o  4 direct studies, 1 meta-analysis o  West J Med. 2001 Mar; 174(3): 207

o  So just stop patching!

Sterile gloves for skin procedures

o  No evidence to support sterile gloves

o  Plenty of evidence for clean gloves

Heal C et al. Med J Aust. 2015;202(1):27-31 Perelman VS et al. Ann Emerg Med. 2004;43(3):362-70

Holland and Singer, Laceration Management, 1999

o  Why does this make perfect sense?

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Model(s)

Dependingonyourstageinlife,themeaningmightchange.

Studyingastudy,tesVngatesto  Be skeptical about studies:

o  Effect size, study size

o  Financial ties, endpoint “flexibility”

o  Measurement of prevailing bias

o  “Why Most Published Research Findings Are False”

o  http://journals.plos.org/plosmedicine/article/asset?id=10.1371%2Fjournal.pmed.0020124.PDF - John Ioannidis

Combined composite endpoints

o  How many ways to die. o  https://youtu.be/IJNR2EpS0jw

o  Can each patient have all endpoints? o  Frequently together: MI, stroke, death

o  Where does the power/effect lie? o  All the difference may lie in one of the points

o  It is a tale told by an idiot, full of sound and fury Signifying nothing. — Macbeth (Act 5, Scene 5, line 28)

Surrogate markers

o  Operation was a success, the patient died. o  Disease-oriented measurements o  Look for lab values: cholesterol v years

o  Publish item not of value to patient o  Look for POEM, not DOE o  Patient Oriented Evidence that Matters

o  Discern what is of value to the patient.

Lies, Damn Lies and Statistics

o  Significance, statistical v clinical o  Large enough study with enough

endpoints can reach any conclusion. o  Horizontal earlobes = ASCVD risk

o  % v absolute numbers o  28% increased of AKI for PPI

o  11% to 15% (∆=4%)

o  Doubled risk! (1% → 2%)

P-values

o  Statistical and clinical significance are different! o  P-value o  Look for lab values: cholesterol v years

o  Publish item not of value to patient o  Look for POEM, not DOE o  Patient Oriented Evidence that Matters

o  Discern what is of value to the patient.

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Thestatement’ssixprinciples,manyofwhichaddressmisconcepVonsandmisuseofthep-value,arethefollowing:1.P-valuescanindicatehowincompaVblethedataarewithaspecifiedstaVsVcalmodel.2.P-valuesdonotmeasuretheprobabilitythatthestudiedhypothesisistrue,ortheprobabilitythatthedatawereproducedbyrandomchancealone.3.ScienVficconclusionsandbusinessorpolicydecisionsshouldnotbebasedonlyonwhetherap-valuepassesaspecificthreshold.4.ProperinferencerequiresfullreporVngandtransparency.5.Ap-value,orstaVsVcalsignificance,doesnotmeasurethesizeofaneffectortheimportanceofaresult.6.Byitself,ap-valuedoesnotprovideagoodmeasureofevidenceregardingamodelorhypothesis.hPps://www.amstat.org/newsroom/pressreleases/P-valueStatement.pdf

NNT/NNH/NNS

o  Number Needed to Treat / Harm o  Risk = chance of benefit or harm o  Not everyone benefits from statins o  Some are harmed (myopathy, LFT) o  Very unlikely the 2 groups are the same. o  A few benefit hugely, most benefit little.

o  Number Needed to Screen

Paradigms=perspecVves

hPp://www.dentalcarerx.com/images/prescripVon_coverage_plan.jpg

hPp://image.slidesharecdn.com/computerandnursingpracVce-151119170510-lva1-app6891/95/computer-and-nursing-pracVce-9-638.jpg?cb=1447952892

Allergy Oddities

o  Allergies – (definitions count!) o  Most PCN allergies are side effects o  “Allergy” 0.7 – 10%, anaphylaxis 0.004% o  Skin reactions atopic or viral interaction o  Skin test discerns at-risk group. o  Cephalosporin cross-reactivity myth; atopy

o J Adv Pharm Technol Res. 2010 Jan-Mar; 1(1): 11–17

o http://www.uptodate.com/contents/penicillin-allergy-immediate-reactions

Allergy Oddities

o  Iodine allergy o  (Think about it.)

o  Shellfish = iodine; protein tropomysin o  http://cdn.intechopen.com/pdfs/31774/InTech-

Characterization_of_seafood_proteins_causing_allergic_diseases.pdf

o  Conflated with iodine o  https://radiology.ucsf.edu/patient-care/patient-

safety/contrast/iodine-allergy

Sowhatshouldyoudo?

o  Read widely and critically.

o  Understand every system is designed to achieve the results it gets.

o  If something seems divergent, it probably is.

o  Have a little humor about all this; none of us are getting out alive!

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Resources

•  http://statistically-funny.blogspot.com/2014/11/biomarkers-unlimited-accept-only-our.html

•  http://www.clinicaladvisor.com/the-waiting-room/exploring-the-lidocaine-with-epinephrine-myth-hospital-emergency-medicine/article/393435/ and ff (PA-C source)

•  http://www.ncbi.nlm.nih.gov/pmc/articles/PMC1070811/pdf/wjm17200208.pdf