in Conner et al.)
Other supplementary texts
Other Book Chapters and Online resources that meet inclusion criteria 16 3 27 Texts • 6 Reviews • 15 Book chapters • 6 Online resources Inclusion • Clinical management focus • Acute poisoning • Pesticide (not nerve gas) • Current literature
(Publication last 5 years)
Exclusion
• Non clinically focussed • No management
instruction
• Environmental focus • Chronic exposure focus • Nerve agent texts • Publication < 2008 • Non English language
The list of supplementary texts was guided by previously published literature reviews on aspects of OP poisoning management(41, 57). A diagram outlining the search strategy is shown in Figure 2-1.
We asked the literature 59 specific questions relating to information about 5 domains covering a range of issues relevant to AChE recommendations in OP poisoning. These questions were constructed by a consensus amongst experts in the field. The broad domains of inquiry included recommendations for AChE in confirming diagnosis and assessing severity of OP poisoning, guiding oxime therapy and patient discharge, and pitfalls in measurement and collection, as well as difficulties in interpretation of assay results (Table 2-1). We also recorded for each specific point that was covered, whether the various texts cited the scientific literature, and the number of citations quoted if more than one source was referenced.
Results
Table 2-1 lists 27 texts (3, 58-83) that were analysed to answer the research questions. This includes of 15 book chapters, 6 review articles, and 6 monographs from online databases.
Our search strategy identified a total of 304 hits on Google Scholar, 59 review articles from a Pubmed search, and 36 texts from other published clinical reviews on OP poisoning from the search terms used, but the list was refined to the final 27 texts based on selection criteria outlined in Figure 2-1. The majority of texts were excluded because of their focus on basic science or non-clinical aspects of the pharmacology of OP poisoning, environmental poisoning or poisoning by nerve agents.
Almost all the texts (26/27) recommended the measurement of AChE for some aspect of OP poisoning management. Most recommended measurement of the assay in the
Figure 2-2 Coverage of topics on AChE recommendations for guiding clinical management
context of confirmation of diagnosis (23/27), and it was less frequently mentioned in the context of guidance of oxime therapy (14/27), and patient discharge (6/27) (Figure 2-2). The potential pitfalls of measurement of AChE were not widely covered, for example, caution about incorrect collection technique was only mention in 6/27 texts (Figure 2- 3).
Specific cut-off points or reference values were lacking across the range of topics explored. Specific values were provided in less than half (11/23) the texts that
recommended AChE for diagnosis, and in 1 out of the 6 texts that recommended it for discharge. Of the 13 texts that suggested AChE could be used to guide oxime therapy none provided specific values to guide clinical decisions (Figure 2-2).
AChE biochemistry was variably covered. Some points, such as the distinction between RBC-AChE and PChE (25/27) were made by nearly all the texts. However, other details that were more focused on the clinical application of these biomarkers, such as PChE being a less specific marker of poisoning (6/27), were only covered in a minority of texts (Figure 2-3).
Citation of scientific literature
There was a large variation amongst texts in how often information was supported by citation. The total number of citations per text varied from 0 to 37 in relation to the 59 review questions (Figure 2-4a). On average the review articles were more likely to cite the literature having a median of 4.5 citations per text, than book reviews or online resources where there was median of 1 citations per text (see Figure 2-4b). However, variation was also noted within all subgroups of review articles, textbook chapters and online monographs, where there were 1 or 2 outliers who quoted much more literature than average. It was also noted that citations for recommendations varied by topic. The proportion of recommendations with citations supporting pitfalls of measurement of AChE was almost double (33%) that for use of AChE in diagnosis, oxime therapy and discharge (17% each) (Figure 2-4c).
Figure 2-3 Coverage of topics on AChE biochemistry and pitfalls in measurement and interpretation of assays
Figure 2-4 Evaluation of citations quoted in chapter on OP poisoning, showing a) the total number of citations per text, b) the number of citations by type of text, and c) the proportion of recommendations for different domains of OP poisoning that refer to evidence.
Eddleston et al. Jokanovic Balali-Mood et al.
Paudyal Aardema et al.Leibson et al.Goldfrank
GuptaSatohReigartBarlie Hayes' handbook
Olson Fernando
Murray et al. Rosen
CameronTintinalliDavidCurrent Oxford handbook
PoisindexToxinzeMedicineWikitoxUpToDateToxbase 0
10 20 30 40
Total number of citations per text
n u m b e r o f c ita tio n s Review Book Chapter Online Resource 0 10 20 30 40 Type of resource N u m b e r o f c ita tio n s
Total number or citation by "Type of Resource"
0.0 0.5 1.0
Pitfalls in measurement Discharge Oxime therapy Diagnosis
Proportion including citation
T
o
p
ic
Proportion of topics/ recommendations backed up with reference to literature
0.33 0.17 0.17 0.17