Best Evidence Topics


  • Submitted by:Daniel Mercier - Emergency Medicine Resident
  • Institution:Grand Rapids Medical Education and Research/Michigan State University
  • Date submitted:4th March 2006
Before CA, i rated this paper: 7/10
1 Objectives and hypotheses
1.1 Are the objectives of the study clearly stated?
  Yes. Is a venous lactate associated with an increase risk of death in ED patients with infection?
2 Design
2.1 Is the study design suitable for the objectives?
  YEs. Prospective review of all patients admitted with infection as a primary diagnosis.
2.2 Who / what was studied?
  All patients admitted with an infection related diagnosis who had lactate drawn at ED presentation.
2.3 Was a control group used if appropriate?
2.4 Were outcomes defined at the start of the study?
Primary outcome = mortality at 1 month.
Secondary outcome = mortality at 3 days.
2.5 Was this the right sample to answer the objectives?
2.6 Is the study large enough to achieve its objectives? Have sample size estimates been performed?
  Unknown. No sample size estimates provided.
2.7 Were all subjects accounted for?
2.8 Were all appropriate outcomes considered?
28 day mortality = primary outcome.
3 day mortality = secndary outcome.
Patients discharged earlier were considered "alive."
2.9 Has ethical approval been obtained if appropriate?
3 Measurement and observation
3.1 Is it clear what was measured, how it was measured and what the outcomes were?
  1. Lactate from venous draw. No standardization of timing of draw but patient had to have the draw done in the ED.
2. Death
3.2 Was the assessment of outcomes blinded?
3.3 Was follow up sufficiently long and complete?
3.4 Are the measurements valid?
3.5 Are the measurements reliable?
3.6 Are the measurements reproducible?
  Unclear, but based on attempt to include all patients admitted with infection as primary diagnosis who were seen in the ED, the results appear generalizable to all ED practices.
4 Presentation of results
4.1 Are the basic data adequately described?
4.2 Are the results presented clearly, objectively and in sufficient detail to enable readers to make their own judgement?
4.3 How large are the effects within a specified time?
  105 primary outcome events occured for 1278 patients over 28 days.
4.4 Are the results internally consistent, i.e. do the numbers add up properly?
5 Analysis
5.1 Are the data suitable for analysis?
5.2 Are the methods appropriate to the data?
  Yes. But standardization of lactate could be more clearly defined.
5.3 Are any statistics correctly performed and interpreted?
6 Discussion
6.1 Are the results discussed in relation to existing knowledge on the subject and study objectives?
6.2 Is the discussion biased?
7 Interpretation
7.1 Are the author's conclusions justified by the data?
7.2 What level of evidence has this paper presented? (using CEBM levels)
7.3 Does this paper help me to answer my problem?
  No. Lactate may be an indicator of poor prognosis in patients with infection buy may also simply be a covariate of another factor.
After CA, i rated this paper: 6/10
8 Implementation
8.1 Can any necessary change be implemented in practice?
  Lactate levels can be drawn on all patients with infection necessitating hospital admisson to aid in overall risk stratification of patient.
8.2 What aids to implementation exist?
  Venous blood routinely drawn from patients.
8.3 What barriers to implementation exist?
  Cost of additional study (lactate).
8.4 Are the study patients similar to your own?
  Yes. Large, tertiary referral, level I trauma center.
8.5 Does the paper give any conclusions that will affect what you will offer or tell your patient?
  Paper suggests lactate > 4.0 in patients with infection have a very high mortality rate. Lactate level alone (if elevated) will not lead me to give a patient a poor prognosis unless other signs of grave illness exist (hypotension, diffuse infection by exam, etc.)