Reviewer's report 
 Preliminary report of a gas conditioner to improve operational reliability of cryotherapy in Title: 
developing countries. 
 1  21 June 2005 Version: Date: 
 PD Blumenthal Reviewer: 
Reviewer's report: 
General 
The authors assess the value of a device designed to dry carbon dioxide gas for use when the gas may be moist as a means of improving the expediency of cervical cryotherapy procedures. While the results could be pertinent to current practice, in order to enhance the clinical relevance of the 
piece, as well as make it stronger and more valid, the authors should consider the following points: 
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Major Compulsory Revisions (that the author must respond to before a decision on publication can 
be reached) The authors assess the value of a device designed to dry carbon dioxide gas for use when the gas 
may be moist as a means of improving the expediency of cervical cryotherapy procedures. While 
the results could be pertinent to current practice, in order to enhance the clinical relevance of the 
piece, as well as make it stronger and more valid, the authors should consider the following points: 
1. Synopsis. Suggest that dessicator be used in place of conditioner since it is more specific. Also, 
although producing the device may have been simple and inexpensive for these authors, since the 
generalizability of the paper is questionable, simple and low cost should be eliminated from the 
synopsis. Thus the Synopsis would read, A pilot experience with a CO2 gas dessicator indicates that 
it may improve cryotherapy operational consistency in developing countries. 
2. Abstract:Methods. Again, would advise against subject terms such a simple. From the diagram, it 
doesnt look so simple to me. 
3. Abstract Methods: It seems there is something inconsistent about saying anecdotal and evidence. 
If an anecdotal experience is being reported, then, thats what it was, and using evidence may be 
somewhat misleading. Were there any actual outcome variables? 
4. Abstract: results. See also point 12 below. It seems odd that the there would be a failure when the 
device was used in conjunction with the cough technique. 
5. Abstract: conclusion. Since may be the only part of the paper that many people read, it is 
important not to oversell. From this experience I would conclude This prototype cryotherapy gas 
conditioner is a potential solution for low-resource settings experiencing cryotherapy device malfunction. 
6. Page 3 Line 4. Since some readers may not be familiar with cryotherapy procedures and the 
problem being described, suggest adding of gas flow right after blockage. 
7. Page 4 Line 1. Was this an actual trial? Or was it a setting in which another anecdotal experience 
was obtained? 
8. Page 5 Line 19. Since, if improperly constructed the device could literally explode, perhaps 
exploded view is not the most desirable term. Suggest detailed view. 
9. Page 5 Line 19. The cost provided is that of the first time construction and assembly of the device. 
But the Drierite is a consumable. How long does a dose last and how much to resupply? Is this 
material available in developing countries? If not, how would they resupply? How much would it 
cost? How long would it take to get delivery? 
10. Page 6 Line 19. How many procedures in total were performed? 
11. Page 8 Line 2. One factor that may promote blockage despite using the cough technique, may 
relate to the number of cases being performed in a short period of time. If a several cases are 
performed in rapid sequence, then the gas tank inevitably warms slightly due to the motion of the 
gas, and the pressure also drops somewhat. Conversely if procedures are only performed relatively 
well spaced temporally (for example an hour or two between procedures) the temperature in the 
tank drops again, and the pressure has a chance to rise prior to the next procedure. This may 
explain why some centers have blockage problems while others do not. Further, it may explain why 
blockage might be noted in training settings (where procedures on models or patients might be performed in rapid succession). Certainly it appears that in the series of procedures performed in Ghana, the procedures were done in relatively close succession, which may not be generalizable to 
what would happen in a clinic if a procedure were only performed once in a while. This also applies 
to the rationale the authors are trying to find on Page 9 Line 9. 
12. Page 8 Line 17. Although it is only one case, how do the authors explain that blockage occurred 
when the device was used in association with the cough technique? Perhaps it is related to the 
comment immediately above. 
13. Page 10 Line 9. The authors spend considerable time mentioning that the reports from Kenya 
and Peru are anecdotal and subject to bias. Then they state that studies were done in 3 countries. 
Since no recorded data are presented on the anecdotal experiences in Kenya and Peru, mention of this experience is confined to background only. The paper itself should just deal with the Ghanaian experience. 
14. Page 11 Conclusion. The authors should be somewhat more circumspect about what they have 
proven, and should avoid some of the subjective terms used in this section. For example, based on 
the data provided here promises may be premature; might or potentially would be more consonant 
with the evidence. $40 may be inexpensive in the US, but the authors dont mention the cost of the 
drying agent and whether materials to these specifications could be obtained in developing 
countries. Also the first line and last line are essentially the same. 
15. Figure 4 should include the actual n in addition to the percentages. It is also unclear what is 
meant by interval between freezing. 
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Minor Essential Revisions (such as missing labels on figures, or the wrong use of a term, which the 
author can be trusted to correct) 
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Discretionary Revisions (which the author can choose to ignore) 
 Unable to decide on acceptance or rejection until the authors have responded to the What next?: 
major compulsory revisions 
 An article whose findings are important to those with closely related research Level of interest: 
interests 
 Acceptable Quality of written English: 
 Yes Statistical review: 
Declaration of competing interests: 
I declare that I have no competing interests.