Research on a Non-Invasive Hemoglobin Measurement System Based on Four-Wavelength Photoplethysmography

Round 1

Reviewer 1 Report

The paper is well written and properly reports significant scientific output.

Conclusion and reference list is to be extended!

In Figure 2. (Block diagram of four-wavelength PPG signal acquisition system) in the left site of the picture is a Chinese letter 

Author Response

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Reviewer 2 Report

The authors described a system for measuring the homoglobin level. The system consists of a PPG aquisation system followed by offline processing and classification of the measured data. The results have been validated in the experimental part. What I see from this paper that the contributions are not very clear or insignificant. For instance, the authors didn't discuss related works and didn't provide with the research gap that needs to be addressed. I advise the authors to add a section and show the novelity of the proposed system with the latest one. I recommend for instance to compare their system with the following references: 

1) Fan, Z.; Zhou, Y.; Zhai, H.; Wang, Q.; He, H. A Smartphone-Based Biosensor for Non-Invasive Monitoring of Total Hemoglobin Concentration in Humans with High Accuracy. Biosensors 2022, 12, 781. https://doi.org/10.3390/bios12100781

2)Saracoglu, A., Abdullayev, R., Sakar, M. et al. Continuous hemoglobin measurement during frontal advancement operations can improve patient outcomes. J Clin Monit Comput 36, 1689–1695 (2022). https://doi.org/10.1007/s10877-022-00813-5

3)S. Ghosal, D. Das, V. Udutalapally, A. K. Talukder and S. Misra, "sHEMO: Smartphone Spectroscopy for Blood Hemoglobin Level Monitoring in Smart Anemia-Care," in IEEE Sensors Journal, vol. 21, no. 6, pp. 8520-8529, 15 March15, 2021, doi: 10.1109/JSEN.2020.3044386.

Author Response

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Reviewer 3 Report

The paper presents a novel and interesting approach to non-invasive hemoglobin concentration measurement using a combination of four-wavelength photoplethysmography (PPG) signals and machine learning. The authors provide a comprehensive study on the feature selection and prediction models used for the proposed method.

 

However, the study has some limitations that should be addressed before publication. First, the sample size of 58 human fingertip photoelectric volumetric pulse wave signals may not be sufficient to generalize the proposed method to larger populations. Second, although Figures 6 and 7 demonstrate the difference between the new and standard procedure methods, it would be useful to compare the proposed method with gold-standard laboratory-based hemoglobin measurement methods to validate its accuracy.

 

Additionally, all the resolutions of the figures should be improved, and the format of the figures should be finalized and made uniform. In Figure 2, the Chinese characters for "手指" should be replaced with the English word "Finger". Regarding Figure 3, the main interface of the host computer software may not be meaningful, and it might be better to include this as supplementary materials with other screenshots to demonstrate how the software and the procedure work.

 

Lastly, in Figure 4, the font size of the words is too small to read. The authors should provide more information on how they determined the start and end points of t1, t2, and t3, especially the end point of t2, as it may not be clear to the reader.

 

Author Response

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Reviewer 4 Report

i am grateful for the opportunity to review your manuscript. 

i offer the following for your consideration:

- in the first paragraph of the Introduction, please either change "of red blood cell" to "of red blood cells", or to "of a red blood cell". still within this paragraph, i feel there is no need to capitalise either 'Preschool' or 'Teenagers'.

- in the second paragraph of the Introduction, you may re-phrase "The PPG, another..." to "PPG is another...". still in the same paragraph, please add "With" in front of "The development of machine learning, ...". still in the same paragraph, please re-express "scholars at home and abroad" because the readership of the journal will not be exclusively from mainland China (and therefore the concept of where 'home' is will vary). you may simply delete "at home and abroad" so that the sentence then reads "... scholar have conducted ..." still within the same paragraph, please take care to insert a single blank space after the period / full-stop after citation [6], [7], and [8].

- likewise, in 2.1.1, please insert a single blank space after the period / full-stop after "... is shown in Figure 1.". please do the same in 2.4 "... were used.Determination ...".

- conversely, in 2.3.2, pleas remove the extra blank space after "... greatly. ".

Author Response

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Round 2

Reviewer 2 Report

Authors have addressed all my points. I urge them to put the dataset in the public domain so that other researchers can use it.  The dataset will further increase the citation and visibility of the journal.

 

Reviewer 3 Report

The authors have addressed all the concerns I raised. Thank you!