Review for 10.1186/1471-230X-14-64 (2014)

Reviewer's report
Title:Discussing the influence of electrode location in the result of esophageal
prolonged pH monitoring
Version: 2Date:25 July 2013
Reviewer: mate knabe
Reviewer's report:
In the present manuscript the authors discuss the influence of electrode location
during PH-metry in 60 GERD patients and 20 control subjects. The main
objective of the study was to determine whether placement of the electrodes only
3 cm above the proximal border of the lower esophageal sphincter results in a
difference in calculation of the DeMeester score. The authors included 60
patients with clinical symptoms of reflux-disease and endoscopic diagnosis of
erosive esophagitis (Los Angeles B, without hiatal hernia). They were compared
to 20 volunteers without gastrointestinal symptoms and normal esophagoscopy.
The study illustrates that placement of the electrodes below the recommended
location leads to a higher DeMeester score and has therefore a relevant
influence on clinical therapy.
The present study is well written and the study design and experimental set-up
was chosen well to answer the initial question. However, there are some
questions which need to be discussed.
Major Compulsory Revisions
1) 60 patients with esophageal symptoms and esophagitis were included. In all
patients surgery was indicated. Can you please comment on the criteria for
surgery as non of the patients have hiatal hernia. Usually fundoplication is
indicated especially in patients with large hernia.
2) Please provide some additional information about the study-group. What were
their complaints? Did they have any extraintestinal symptoms? How many
patients received protone-pump-inhibitors and what dosage? Did they take other
medication which might have influenced reflux? Do you have information about
the average body-mass-index as this has an influence on reflux as well.
3) Please re-discuss the limitation as only patients without hiatal hernia were
included. Diaphragmatic hernia is known as one of the leading reasons for
GERD. (Jones MP, Am J Gastroenterol 2001, and Sontag SJ, et al. J Clin
Gastroenterol 1991;13(6):628–643.) It is described with a prevalence of up to
94% whereas the corresponding prevalence in control subjects ranges from 13%
to 59%. It should be mentioned that the results are only evaluated in patients
without hiatal hernia.
4) The authors describe that no patients had an extension of lower-esophageal
sphincter less than 3 cm. Especially in patients with GERD the length of the
lower-esophageal sphincter is usually significantly shorter than in healthy
controls. The length is evaluated as a risk factor to suffer from reflux.
Please comment on this.
Minor Essential Revisions
Although I´m not a nativ speaker, I would advise you to correct the following
sentences:
1) Abstract : Methods: Two PH-metric catheters containing antimony
electrodes.....
2) Abstract: Conclusion: 2nd sentence: Lower location of the catheter may
strongly affect...
3) Background, 6th paragraph: instead of "eventual" perhaps "possible"
4) Background 7th paragraph: please find a better expression for "that which"
5) Methods, second paragraph: please check this paragraph for english
grammer.
6) Methods, third paragraph: instead of submitted it is perhaps better to use
admitted or .... Esophageal maonometry was performed. Please dobblecheck
7) Methods, 4th paragraph, first sentence: The catheters contained antimony
electrodes.....
8) Methods, 5th paragraph, 3rd sentence: ... collected in the register was
translated....
9) Results: 2nd paragraph, last sentence: ....were significant different from one
another.
10 ) In summary I would recommend to doublecheck the manuscript with a nativ
speaker. Especially some sentences are too long and make it difficult to follow.
Shortening the sentences at some points would make it easier to understand.
Discretionary Revisions
No discretionary revisions.
Level of interest: An article of limited interest
Quality of written English: Needs some language corrections before being
published
Statistical review: No, the manuscript does not need to be seen by a
statistician.
Declaration of competing interests:
I declare I have no competing interests