Best Evidence Topics


Sporer, KA and Khayam-Bashi H
Acetaminophen and Salicylate Serum Levels in Patients With Suicidal Ingestion or Altered Mental Status
American Journal of Emergency Medicine
Volume 14, Issue 5 (September 1996)
  • Submitted by:Leif Meyers - EM resident
  • Institution:GRMERC
  • Date submitted:28th February 2008
Before CA, i rated this paper: 8/10
1 Objectives and hypotheses
1.1 Are the objectives of the study clearly stated?
  Yes. "To help quantify the incidence of clinically relevant acetaminophen and salicylate toxicity that would be missed by relying on the patient's history alone."
2 Design
2.1 Is the study design suitable for the objectives?
  Yes, although a prospective study would be ideal.
2.2 Who / what was studied?
  "...serum acetaminophen and salicylate levels on all patients who presented to the ED of SFGH with a history of suicidal ingestion or AMS with a strong clinical suspicion of ingestion."
2.3 Was a control group used if appropriate?
2.4 Were outcomes defined at the start of the study?
  Yes. Clinically signnificant acetaminophen or salicylate toxicity that would have been missed by history alone.
2.5 Was this the right sample to answer the objectives?
  Yes, retrospective chart audit of all patients with blood levels over 20 months 1992-3 (1,820 patients).
2.6 Is the study large enough to achieve its objectives? Have sample size estimates been performed?
  The sample is large; however, no estimates were performed.
2.7 Were all subjects accounted for?
  No, 86% of patients meeting criteria did not have serum levels drawn.
2.8 Were all appropriate outcomes considered?
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?
  Serum blood levels of acetaminophen and salicylate compared to past medical history from patient.
3.2 Was the assessment of outcomes blinded?
3.3 Was follow up sufficiently long and complete?
3.4 Are the measurements valid?
  Lab measurements were valid, but patient histories were questionable.
3.5 Are the measurements reliable?
3.6 Are the measurements reproducible?
  Yes. Other like studies have had similar findings.
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?
  Yes. Patients with clinically significant intoxication and negative history were individually discussed in the paper.
4.3 How large are the effects within a specified time?
  Of 1820 patients screened 5 had APAP levels >50 and 15 had ASA level >10 with a negative history. All patients with ASA >10 had and anion gap >17.
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?
  Yes. Sufficient number of patients eligable were screened for APAP and ASA.
5.2 Are the methods appropriate to the data?
  Yes. The authors looked at both supratherapeudic levels and signs of toxicity.
5.3 Are any statistics correctly performed and interpreted?
  Yes. History alone missed 0.3% or 5 patients with supratherapeudic APAP levels. History alone missed 0.6% or 15 patients with supratherapeudic ASA levels. All of these patients had anion gaps >17.
6 Discussion
6.1 Are the results discussed in relation to existing knowledge on the subject and study objectives?
  Yes. The authors remarked on prior studies.
6.2 Is the discussion biased?
  No. The authors clearly discuss their logic.
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?
  Yes. The authors clearly discuss the risks of missing a APAP intoxication. They also discuss how AMS and elevated anion gap would effectively screen for supratherapeutic ASA levels.
After CA, i rated this paper: 8/10
8 Implementation
8.1 Can any necessary change be implemented in practice?
  Yes. Routine screening of ASA in patients with normal mental status and a normal anion gap is unnessicery.
8.2 What aids to implementation exist?
  Cost effective.
8.3 What barriers to implementation exist?
  Physician fear of even one ASA toxic patient being missed.
8.4 Are the study patients similar to your own?
  Yes, ED patients with drug overdose or ingestion
8.5 Does the paper give any conclusions that will affect what you will offer or tell your patient?
  Yes. I will no longer routinely screen for ASA. Assessment by the psychiatric team should not be delayed to wait for lab results.