Review for 10.1186/1471-230X-13-98 (2013)

Reviewer's report
Title:Cerebral microdialysis reflects the efficacy of Fractionated Plasma
Separation and Adsorption treatment of acute liver failure earlier than intracranial
pressure - a controlled study in pigs
Version: 1Date:23 April 2013
Reviewer: David Sass
Reviewer's report:
The authors conducted an experiment using a surgical resection model of ALF to
evaluate the role of cerebral microdialysis (MD) in monitoring the efficacy of
FPSA. The efficacy of this FPSA technique as a bridge therapy to decrease ICP
in ALF has previously been demonstrated. In the current experiment, the authors
hypothesized that the benefits (positive influence) of FPSA would be detected
earlier by MD than by measuring ICP.
Overall, the study question was well defined and a working hypothesis was well
stated. The methodology was covered in great detail with very clear narratives on
the surgical procedure, method of anesthesia, post-operative management, MD
and ICP monitoring and FPSA treatment (bridge therapy). The statistical analysis
paragraph is well-detailed, the data appear sound and the written results
paragraphs match what is illustrated in the table and figures. The main limitation
of the study is stated by the authors in their discussion, i.e. the L/P ratio being
significantly higher in the FPSA group vs ALF group in the first 1-2 hours of the
experiment and may have provided an unreliable value, potentially affecting
results in the subsequent hour. In their discussion the authors also expound on
the limitations of glucose, glutamine and glutamate monitoring as a reliable
marker for ALF treatment efficacy. The title and abstract do accurately convey
the study findings and the writing is acceptable.
There are some minor essential revisions for the authors to address:
1. Authors should comment on how the total number of animals (n=21) was
chosen for their experiment and why the control (ALF) and FPSA groups didn't
contain equal numbers?
2. Spelling: Table 1 legend: "laktate", should read "lactate"
3. Spelling: Table 1: "extracelular brain glutamin", should read "extracellular brain
glutamine".
4. Table 1: why were the serum glutamate and glucose levels not tabulated for
the 3 experimental groups?
5. Figures: Why was there no graphical representation (figure) for the arterial
ammonia levels for the 3 experimental groups?
6. Grammar: Discussion, paragraph 2, "various procedures of the bridging
therapy have been suggested" would be better phrased as "various bridging
therapy procedures have been proposed..."
7. Grammare: Discussionm paragraph 2, "the FPSA method decreases the
rise..." should be changed to "the FPSA method attenuates the rise..."
8. The authors mention in the discussion " the fact that ICP rises in the FPSA
group, even if it's significantly lower... suggests a multifactorial origin for cerebral
hypertension in ALF". Thus although the L/P ratio reflects the positive influence
of FPSA treatment EARLIER than ICP, the fact that it only partially ameliorates
the cerebral hypertension, begs the question of the clinical efficacy of FPSA as a
bridge therapy in treating cerebral edema in ALF. With this in mind, the authors
should comment of their experimental findings and their potential clinical value in
altering our current standard clinical practice of managing the ALF patient.
Level of interest: An article whose findings are important to those with closely
related research interests
Quality of written English: Acceptable
Statistical review: Yes, but I do not feel adequately qualified to assess the
statistics.
Declaration of competing interests:
I declare that I have no competing interests.