Clinical Applicability of Electrical Impedance Tomography in Patient-Tailored Ventilation: A Narrative Review

Round 1

Reviewer 1 Report

This narrative review “clinical applicability of electrical impedance tomography in patient-tailored ventilation” reported the clinical possible uses of EIT to adjust protective invasive mechanical ventilation at bedside, avoiding injurious ventilation to the lungs and diaphragm. The authors focus on decremental PEEP titration and tidal volume adjustments. The authors comment about regional measurements that are very important, mainly in heterogeneous diseases like ARDS that can be measured with the EIT, explaining the centre of ventilation, the global inhomogeneity index and the regional ventilation delay. They reported the possible use to evaluate changes in body position. To complete the narrative review, they can also comment about the clinical use of continuous driving pressure measurements, measurement of Pendeluft and lung perfusion.  

Moderate editing of English language required

Author Response

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Author Response File: Author Response.docx

Reviewer 2 Report

Title: Clinical applicability of electrical impedance tomography in 2 patient-tailored ventilation: A narrative review

 

Summary:

  The authors provide a narrative review of the role electrical impedance tomography in optimizing ventilator settings in mechanically ventilated patients.  They review studies of different strategies of PEEP titration, different measurements to assess the distribution of alveolar overdistention and atelectasis, and describe limitations of EIT.

 

Critique:

  Electrical impedance tomography (EIT) is an emerging and potentially under-utilized technology.  A narrative review on it’s potential uses and a review the current literature in each of these roles is an important and useful endeavor.   The author’s seem to have extensive knowledge of the topic and include a lot of important references.  However, much of the is very difficult to understand due to poor sentence syntax, run-on sentences,  and poorly structured paragraphs.  In some instances I was able to understand the concepts after reading a paragraph 3-4 times,  in other cases I still could not figure out exactly the point the author was trying to convey.  I provide some specific examples below. 

    The overall outline of the article could be much better presented.  The article starts with a 50 line paragraph about mechanical ventilation, ARDS and PEEP, but no mention of EIT.   It would seem to me in this type of review it would be best to start with an overview of EIT, how it works, and a description of the different measures represented.  While this is in the article, it is sprinkled throughout the article in various areas, leaving the reader to try to understand what the measurement even means at the same time the clinical scenario is being described.   To add to the confusion, intermittently limitations and anecdotal solutions or tricks  (like fully inflating the mattress to avoid artifacts) are mixed in with the description of the measurements.  

    Much of the article is the description of PEEP titration which is a very controversial topic.  The authors describe the role of EIT relatively well, but it is hard to argue that EIT helps achieve the optimal PEEP when the optimal PEEP is really unknown.  The authors mention this limitation; but I would recommend decreasing the discussion about it overall and focusing more on how EIT gives you insight into how the lung is ventilated which would help a clinician decide on optimal peep.

    The subject matter of the article is relatively complex, therefore if not well written, the article becomes unhelpful and hard to follow.  I would recommend a complete restructuring and re-write.

 

Major points:

The following are specific examples of poor sentence syntax making it hard to follow the author’s point.

Lines 95-98 Because overdistention and alveolar collapse results in decreased compliance increases in regional compliance with lower peep are interpreted as overdistening with the previously set (higher) PEEP levels, where as decrease in regional compliance with lower PEE are interpreted as decruitment.”    This is the opening sentence for the paragraph, and it is very hard to follow.   I think it is trying to say something like “Titrating PEEP based on compliance measurements is difficult because both overdistention and alveolar collapse cane result in lower compliance, but would require opposite titration strategies.” 

 

Line 105-107: “However, the best balance…”    I don’t understand what is trying to be said here.  Do you mean in general in ARDS, despite our best efforts this is distention and atelectasis?  Are you referring to ARDS with the use of EIT? 

 

Line 172-174   “Letting the patient breath spontaneously through the ventilator may thus contribute to reducing the time during which patients are mechanically ventilated..”    This is a very poorly constructed sentence.  Maybe trying to say “Lighter sedation leads to more ventilator free days but the resulting spontaneous respirations put the patient at risk of self-inflicted lung injury?”

 

Line 222: “This ratio was initially called…”   sentence needs re-wording

 

Line 223 The tidal impedance difference…”  This sentence is poorly written and hard to follow.

There are too many examples to provide them all, but these are some key examples.  

 

 

 

Minor grammatical errors.

Line 146: decubitus is not a noun.  I suspect decubitus ulcers or pressure ulcers/injuries is what you meant. 

I honestly think it would have to be completely re-written with an emphasis on being more concise.

Author Response

Please see the attachment.

Author Response File: Author Response.docx

Reviewer 3 Report

Thank you for the opportunity to review this manuscript. Heines and colleagues present a profound narrative review on the clinical applications of electrical impedance tomography. The manuscript is nicely written and is easy to follow. I have only one minor remark: P. 20, line 37. The parameter "TID" should be explained briefly.

 

Author Response

Please see the attachment.

Author Response File: Author Response.docx

Round 2

Reviewer 1 Report

The authors adequately answer the reviewer queries and made the necessary changes in the revised version of their paper. 

The authors adequately answer the reviewer queries and made the necessary changes in the revised version of their paper.