Anatomy of a CAT

1
Anatomy of a CAT

• Malcolm Daniel
• Consultant in Anaesthesia Intensive Care
• Department of Anaesthesia
• Glasgow Royal Infirmary

2
The Problems

• We need information to make decisions.
• How often?
• From 5 times for every in-patient.
• To 2 times for every 3 out-patients.
• We get less than a third of it.

3
The Problems

• Most of our information needs are not met
• Our textbooks are out of date.
• Our journals are disorganised.
• We have limited time to acquire new information.

4
The Problems

• To keep up to date it is estimated
• I need to read 17 articles a day, 365 days a
  year.
• I need to read.
• Dont (well not that much!).
• Nor does anyone else.

5
Median time spent reading about managing patients

• Time management
• From surveys by Dave Sackett at Ground Rounds
• Median - 90 minutes or less per week.
• Need and time available do not add up.

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What I want

• not to have to wade through papers
• not to have to search through Medline
• - get trust someone else to do that for me
• to have an index of the strength of evidence
• to have a one word (or brief) answer
• to see questions that already have answers
• 50 seconds to medical knowledge

7
Information Sources for Use at the Point of Care

• Everything is based on the usefulness equation
• Usefulness Relevance x Validity
• Work

8
Work

• We want information that is easy to access.
• Online you are here already.
• Printable.

9
Validity

• We want information that has the validity clearly
  described.
• Need high quality sound appraisals.
• Level of evidence given.
• SIGN grading of evidence used (see BMJ 2001 323
  334 336).

10
Validity

• Level of evidence is an index of methodological
  quality and risk of bias.
• It does not reflect the clinical importance.
• We need our clinical expertise and common sense
  to determine this.

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Relevance Clinical Importance

• Give more weight to
• Patient-oriented evidence
• mortality, morbidity, quality of life, powerful
  diagnostic tests
• Pay some attention, but give far less weight to
• Disease-oriented evidence
• physiological, or pharmacological end points,
• aetiology

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Critically Appraised Topic (CAT)

• A one page summary
• Declarative title
• Question
• Name of paper
• Search terms
• Design
• Setting
• Patients

• Intervention
• Outcome Measures
• Results
• Table
• Conclusion
• Commentary

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(No Transcript)
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Bottom line read in seconds
15
Get bottom line quickly (seconds)
Tight blood glucose control improves ICU survival
16
Get bottom line quickly (seconds)
Declarative title
Tight blood glucose control improves ICU survival
17
Get bottom line quickly (seconds)
Tight blood glucose control improves ICU survival
Summary of treatment effect, and level of evidence
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Trial details read in minutes
19
Read trial details (minutes)
The Study Single-blinded randomised controlled
trial with intention-to-treat. The Study
Patients All patients admitted to a surgical ICU
in Belgium (62 had cardiac surgery). Median
APACHE 9 (IQ range 7-13). Median TISS 43. 13 had
diabetes. Randomised at ICU admission. All
patients given iv glucose on admission, next day
parenteral / enteral nutrition or enteral
nutrition alone. Matched for blood glucose at
admission. Control group group (N 783 783
analysed) Insulin infusion (1 U.ml -1) started
if glucose gt 12 mmol.l-1, and titrated to range
10.0 - 11.1 mmol.l-1. Blood glucose checked 1 - 4
hourly, algorithm used and discussion with study
clinician not involved in patient care.
Experimental group (N 765 765 analysed)
Insulin infusion (1 unit/ml) started if glucose gt
6.1 mmol.l-1, and titrated to keep glucose in
range 4.4 - 6.1 mmol.l-1. Blood glucose checked 1
- 4 hourly, algorithm used and discussion with
study clinician not involved in patient care.
20
Read trial details (minutes)
Key design validity features
The Study Single-blinded randomised controlled
trial with intention-to-treat. The Study
Patients All patients admitted to a surgical ICU
in Belgium (62 had cardiac surgery). Median
APACHE 9 (IQ range 7-13). Median TISS 43. 13 had
diabetes. Randomised at ICU admission. All
patients given iv glucose on admission, next day
parenteral / enteral nutrition or enteral
nutrition alone. Matched for blood glucose at
admission. Control group group (N 783 783
analysed) Insulin infusion (1 U.ml -1) started
if glucose gt 12 mmol.l-1, and titrated to range
10.0 - 11.1 mmol.l-1. Blood glucose checked 1 - 4
hourly, algorithm used and discussion with study
clinician not involved in patient care.
Experimental group (N 765 765 analysed)
Insulin infusion (1 unit/ml) started if glucose gt
6.1 mmol.l-1, and titrated to keep glucose in
range 4.4 - 6.1 mmol.l-1. Blood glucose checked 1
- 4 hourly, algorithm used and discussion with
study clinician not involved in patient care.
21
Read trial details (minutes)
The Study Single-blinded randomised controlled
trial with intention-to-treat. The Study
Patients All patients admitted to a surgical ICU
in Belgium (62 had cardiac surgery). Median
APACHE 9 (IQ range 7-13). Median TISS 43. 13 had
diabetes. Randomised at ICU admission. All
patients given iv glucose on admission, next day
parenteral / enteral nutrition or enteral
nutrition alone. Matched for blood glucose at
admission. Control group group (N 783 783
analysed) Insulin infusion (1 U.ml -1) started
if glucose gt 12 mmol.l-1, and titrated to range
10.0 - 11.1 mmol.l-1. Blood glucose checked 1 - 4
hourly, algorithm used and discussion with study
clinician not involved in patient care.
Experimental group (N 765 765 analysed)
Insulin infusion (1 unit/ml) started if glucose gt
6.1 mmol.l-1, and titrated to keep glucose in
range 4.4 - 6.1 mmol.l-1. Blood glucose checked 1
- 4 hourly, algorithm used and discussion with
study clinician not involved in patient care.
Intervention (s)
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Read trial details (minutes)
23
Read trial details (minutes)
Outcome (s) of interest
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Read trial details (minutes)
Control group event rate
25
Read trial details (minutes)
Control group event rate
Experimental group event rate
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Read trial details (minutes)
Relative risk reduction
27
Read trial details (minutes)
Relative risk reduction
Absolute risk reduction
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Read trial details (minutes)
Relative risk reduction
Absolute risk reduction
Negative risk reduction an increase !
29
Read trial details (minutes)
Number needed to treat to benefit
30
Read trial details (minutes)
Number needed to treat to benefit
Number needed to treat to harm
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Particularised for your own practice, integrate
with your expertise
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Remember to particularise for your patient

• Predominantly cardiac surgery patients (59 had
  CABG) could this group be more like the DIAGMI
  group of patients?
• No, main effect was reduction in deaths due to
  multiple organ failure due a proven septic focus.
  
• No details provided of algorithm in article
  aimed for normoglycaemia. Now available via
  NEJM website.
• Reduction in sepsis and critical illness
  neuropathy, but are EMG recordings are a
  surrogate end-point.
• Insulin is an inexpensive drug, especially
  compared to activated protein C, and may be more
  widely applicable.
• Only single episodes of hypoglycaemia reported
  with no physical complications.
• We have a higher MR, death (and death due to
  sepsis) is more common per 100 patients, we need
  to treat fewer patients to save a life NNT / f
  29 / 3 10. Note this is a rough estimate.

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Citation details and search strategy, read in
hours
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Read the study (for hours)
Citation/s Intensive Insulin Therapy in
Critically Ill Patients NEJM 2001 345 1359 -
67. Three-part Clinical Question In ICU
patients, does the use of intensive insulin
therapy to maintain tight blood glucose control,
compared to standard therapy, lead to
improvements in ICU outcome?Search Terms 1. exp
sepsis/ or severe sep.tw or sept.tw or
sepsi.tw (50301), 2. exp critical care/ or
critical ca.tw or intensive ca.tw (22553), 3.
exp insulin or insuli.tw (50202), 4. 1 and 2 and
3 (25), 5. therapy filter (652119), 6. 4 and 5
(17)
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Read the study (for hours)
Hyperlink to journal web site
Citation/s Intensive Insulin Therapy in
Critically Ill Patients NEJM 2001 345 1359 -
67. Three-part Clinical Question In ICU
patients, does the use of intensive insulin
therapy to maintain tight blood glucose control,
compared to standard therapy, lead to
improvements in ICU outcome?Search Terms 1. exp
sepsis/ or severe sep.tw or sept.tw or
sepsi.tw (50301), 2. exp critical care/ or
critical ca.tw or intensive ca.tw (22553), 3.
exp insulin or insuli.tw (50202), 4. 1 and 2 and
3 (25), 5. therapy filter (652119), 6. 4 and 5
(17)
36
Read the study (for hours)
Citation/s Intensive Insulin Therapy in
Critically Ill Patients NEJM 2001 345 1359 -
67. Three-part Clinical Question In ICU
patients, does the use of intensive insulin
therapy to maintain tight blood glucose control,
compared to standard therapy, lead to
improvements in ICU outcome?Search Terms 1. exp
sepsis/ or severe sep.tw or sept.tw or
sepsi.tw (50301), 2. exp critical care/ or
critical ca.tw or intensive ca.tw (22553), 3.
exp insulin or insuli.tw (50202), 4. 1 and 2 and
3 (25), 5. therapy filter (652119), 6. 4 and 5
(17)
Search terms used, for reference, and to repeat
in future
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Critically Appraised Topics

• Pros
• Easy to read
• 2-3000 words reduced to 300 words
• Levels of evidence
• Important measures summarised - NNTs

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Critically Appraised Topics

• Pros
• Easy to read
• 2-3000 words reduced to 300 words
• Levels of evidence
• Important measures summarised - NNTs

• Cons
• Trusting someone else appraisals
• Treatment effect summarised but decision left
  to you
• Only one paper per CAT
• May not answer your question

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Bottom Line

• 1. The new challenge in medicine is information
  mastery.
• 2. In order to survive in the information age
  every clinician needs tools, based on the
  information mastery equation
• Usefulness (Relevance x Validity)/ Work
• 3. CATs have evolved to be highly useful !

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How could this work?

• If 2 people from each ICU around the country
  (world ?)
• Wrote two CATs per year.
• What a database we would have
• - Valid, relevant, easy to access.
• This is the future..watch this website.