9. Sensitivity 97%
Specificity 54%
H-FAB in AMI
125125
44
261261
315315
H-H-
FABPFABP
10. What does a +ve test
result mean?
What does a -ve test result
mean?
What answers do we really
get from a Truth table?
125125
44
261261
315315
H-H-
FABPFABP
11. H-FAB testing for AMI
• A +ve test means they have
the diagnosis
• A +ve test means they
probably have the diagnosis
• A +ve test means they are
more likely to have the
diagnosis than before I did
the test
125125
44
261261
315315
H-H-
FABPFABP
12.
13. • Medicine is a science of
uncertainty and an art of
probability.
22. Example - PERC rule
• Age>49
• Pulse>100
• Pulse Ox<95%
• Current haemoptysis
• Oestrogen use
• Previous venous thromboembolism
• Recent surgery
• Unilateral leg swelling
PERC Rule
sens = 97.4%
spec = 21.9%
^ Kline, JA; et al (2008).
"Prospective multicenter evaluation of the pulmonary embolism rule-out criteria".
Journal of Thrombosis and Haemostasis 6 (5): 772–780.
45. Diagnosis missedDiagnosis missed
They don’t comeThey don’t come
backback
It gets worseIt gets worse
The treatmentThe treatment
does not workdoes not work
Harm takes placeHarm takes place
They get betterThey get better
anywayanyway
They do comeThey do come
backback
The treatmentThe treatment
worksworks
Significant harmSignificant harm
avoidedavoided
Diagnosis madeDiagnosis made
..but the diagnosis is..but the diagnosis is
missed again!missed again!
53. • Good problem solving, sound judgement and
effective clinical decision making are
considered the highest attributes of physicians.
The theory and practice of clinical decision making
Croskerry P. Can J Anaesth 2005;52:1-8
54. Only when disclosure of uncertainty
becomes commonplace in medical practice
will the physician/patient relationship evolve
to a level of greater understanding and
satisfaction for both the physician and
patient.
55. 4 Things
• You are not a diagnostician
• You are a risky doctor
• You get lucky (a lot)
• The dangers of diagnosis
56. 4 Things
• You make probability assessments
• You take risks (but you understand them)
• Even when you miss, you usually get lucky
• Pursuing a diagnosis is not always right
Notes de l'éditeur
General question as ice breaker Common reasons likely to be labels, prognosis, therapy. Ultimately because it is useful to know. BUT the key to a rational diagnostician is that it should be beneficial for the patient and not just the physician
55 year old man with 2 hour hx of chest pain. no risk factors. previously fit and well
Digivote slide Answer is 90-95%
Digivote LR +ve 2.138 LR -ve 0.057
So as a clinician we have no idea whether our patient has the right diagnosis or not. We just know that they probably do or they probably don’t. Even with tests that have a high sensitivity.
Howard Atwood Kelly (February 20, 1858 – January 12, 1943) was an American gynecolo gist . He was one of the "Big Four" founding professors at Johns Hopkins Hospit al . [1] (The "Big Four" were William Osler , Professor of Medicine; Will iam Stewart H alsted , Professor of Surgery; Howard A . Kelly, Professor of G ynecology; and William H. Welch , Professor of Pathology.) Kelly is credited with establishing gynecology as a true specialty. [2] Harvey Williams Cushing , M.D. (April 8, 1869 - October 7, 1939), was an American neurosurgeon and a pioneer of brain su rger y, and the first to describe Cushing's syndrome . [1] He i s often call ed the "father of modern neuro surge ry. Thayer prof medicine at John Hoplins
Point 1 you are not a diagnostician
Point 2 is that..... Probability So if we accept that we have a probability issue then we have a problem of risk.
chest pain tests.
Digivote
1666 ?PE patients in 13 US and NZ EDs Gestalt plus PERC gives the following PERC Rule sens = 97.4% spec = 21.9% Designed with acceptable miss rate of 2% Even in this study PEs were missed. ^ Kline, JA; Courtney, DM; Kabrhel, C; Moore, CL; Smithline, HA; Plewa, MC; Richman, PB; O'Neil, BJ et al (2008). "Prospective multicenter evaluation of the pulmonary embolism rule-out criteria" . Journal of Thrombosis and Haemostasis 6 (5): 772–780. doi : 10.1111/j.1538-7836.2008.02944.x . PMID 18318689 .
Digivote
6.9 % pre test probability of PE. Kline study multicentre 8138 patients gestalt plus PERC
Point 3
Sequence has to be completefor harm to occur IN appendicitis. Miss diagnosis, not come back early, not get recognised, not get to theatre, not respond to treatment, not survive.
Sequence has to be complete for harm to occur IN appendicitis. Miss diagnosis, not come back early, not get recognised, not get to theatre, not respond to treatment, not survive.
So what have we established thus far?
Monty hall Game Show - let’s make a deal in the 70s
headache low risk chest pain dvt/vte appendicitis bacterial infections in children meningitis
