Alfred H. Stammers, MSA, CCP
Objective: Identify means of grading the literature for its value and determining clinical benefit.
Each practitioner uses a variety of resources to gain knowledge that will influence their interventions when establishing their protocols for patient care. Although the term ‘opinion’ imparts connotations loosely based upon fact, it is often these judgments that clinicians use to provide care to their patients. How these opinions are formed therefore, becomes critical towards the validity of the application, and ultimately, how patients fare post-intervention.
The resources available to all individuals involved in extracorporeal techniques are diverse and are ranked according to the critical means as to how they were produced. The primary force that has influenced the expansion of knowledge is undoubtedly the access to electronic databases and the use of search engines. Prior to the use of web-based search engines, which began in the mid-1990’s, most searching was accomplished through use of textbooks, personal subscriptions to journals, and from sources such as Current Contents. This required significant labor and resulted in reference lists published in the bibliography section of papers that were approximately half the size that are found in today’s publications. Although studies comparing the accuracy of citations pre web-based search engines with those post, its is not inconceivable that the increase in quantity of cited references during current times may be in excess of what is needed to support the paper. The web has done more to place literature at the fingertips of any clinician who has a computer with high-speed access. There are numerous databases with the most familiar, and far reaching, being that published by the National Institutes of Health (www.nih.gov/) through the National Library of Medicine (www.nlm.nih.gov/) and PubMed (www.ncbi.nlm.nih.gov/entrez/). There are other sources of information and these include standards and guidelines for practice. Several perfusion organizations publish these, including AmSECT. These are usually produced through the efforts of ad hoc type committees which consist of opinion leaders who meet and generate documents on practice based upon their informed opinion and published papers. These Guidelines are then sent to societal members for input and the results accumulated and incorporated in to the document prior to distribution. The best example of these are those published by the Accreditation Committee on Perfusion Education through the Committee on Accreditation for Allied Health Educational Programs (CAAHEP). (www.caahep.org/documents/PERF_SG.pdf)
Identifying resources in the literature and ranking them according to their value is made more difficult buy the level of action that one seeks to achieve by its use. Although ‘clinical’ citations require outcome based studies, the foundation upon which these are established are almost always based upon ‘laboratory’ studies. These will be omitted from the list below not because of their lack of importance, bit because the extrapolation into the clinical environment remains to be shown. The ranking of literature as to its validity with interpretation of data is listed as highest to lowest.
Ranking of Literature
1. Journal Citations in Indexed Sources
a. Scientific Articles
i. Randomized Controlled Trials
ii. Prospecticve Observational Cohort Studiesa
iii. Non-randomized Interventional Trials with Concurrent or Historical Controls, Case-control Studies
iv. Cross Sectional Studies, Case Series
b. Case Studies
c. Review Articles
2. Evidence Summaries
a. Systematic Reviews
b. Abstract Summaries
3. Clinical Guidelines
4. Textbooks and Monographs
5. Instructional Manuals and Product Inserts
