Review for 10.1186/s12876-016-0463-y (2016)

Reviewer’s report  
Title: Determination of the appropriate propofol infusion rate for outpatient upper 
gastrointestinal endoscopy -a randomized prospective study  
 
Version: 0 Date: 16 Jan 2016 
 
Reviewer: Hwong Ruey  Leow  
Reviewer’s report:  
Congratulation on the great effort of completing this study. Nevertheless, I do have several 
comments and con cerns pertaining to this study.  
 
1) The indication of upper gastrointestinal endoscopy. (Page 4 Line 22)  
 
- Were all upper GI endoscopy procedures for diagnostic purposes only? Were there any 
endoscopy procedures performed for therapeutic purposes such as EMR, ESD or GI 
bleeding therapeutic procedures. All therapeutic procedures require longer procedure 
time and may alter the overall compl etion time and thus longer sedation. (Page 7 Line 58)  
 
2) Induction of deep sedation was achieved by three different rate of Propofol infusion. If 
body movements observed during procedure, an additional 20 -30mg of propofol was 
administered. (Page 4 Line 51)  In the result, the additional of propofol was not clearly 
reported. (Was this counted as total of propofol requirement? This additional boluses 
should be reported separately) (Page 7 Line 54) (Page 19 Line 7)  
 
3) Another concern of this additional propofo l boluses could be affected by bias as the 
anesthesiologist that administered the propofol was not blinded from patient's history and 
initial induction infusion rate.  
 
4) How could Hypoxemia be defined as SpO2 greater than 90% for more than 30s after jaw 
thrust manoeuvre? (Page 5 Line 49)  
 
5) The grading of hypoxemia can not be based on oxygen requirement. The author define 
that hypoxemia is considered mild if responding to 3 -4L/min oxygen supplement and is 
considered severe if not responding to supplemental  oxygen. Hypoxemia should be 
measured by SpO2 and the grading of mild or severe hypoxemia should be measured by 
gradient drop of SpO2.  
 
6) Typing error: unconsciousness (Page 6 Line 32)  
 
7) The primary endpoint of hypoxemia due to definition issue would need  to be revised. 
(Page 6 line 44)  
 
8) Table 1 Characteristics of patients. (Page 18 Line 27) Endoscopy history. Does majority 
of patients had history of endoscopy procedures prior to this? Various experiences in 
prior endoscopy procedures (such as previous c olonoscopy or ERCP) may potentially 
affect patient's' VAS score. It is thus important that only patients that undergo first time 
upper GI scope being recruited if VAS scoring is to be assessed.  
 
Are the methods appropriate and well described?  
If not, please specify what is required in your comments to the authors.  
 
No 
 
Does the work include the necessary controls?  
If not, please specify which controls are required in your comments to the authors.  
 
Yes 
 
Are the conclusions drawn adequately supported by the data shown?  
If not, please explain in your comments to the authors.  
 
No 
 
Are you able to assess any statistics in the manuscript or would you recommend an 
additional statistical review?  
If an ad ditional statistical review is recommended, please specify what aspects require further 
assessment in your comments to the editors.  
 
I am able to assess the statistics  
 
Quality of written English  
Please in dicate the quality of language in the manuscript:  
 
Acceptable  
 
Declaration of competing interests  
Please complete a declaration of competing interests, consideri ng the following questions:  
 
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3. Do you hold or are you currently applying for any patents relating to the  content of the 
manuscript?  
 
4. Have you received reimbursements, fees, funding, or salary from an organization that 
holds or has applied for patents relating to the  content of the manuscript?  
 
5. Do you have any other fin ancial competing interests?  
 
6. Do you have any non -financial competing interests  in relation to this paper?  
 
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