Review for 10.1186/s12876-021-02089-6 (2022)

Title: Comparison of the innovative endoscopic oropharyngeal airway and the conventional
mouthpiece in elderly outpatients undergoing esophagogastroduodenoscopy under sedation: a
prospective and randomized study
Version: 1 Date: 14 Nov 2021
Reviewer's report:
This is an interesting randomized study in which an innovative airway device was compared
to a standard mouth piece for sedation of vulnerable/elderly patients during upper endoscopy.
The authors were able to demonstrate more favourable cardiorespiratory parameters for the
innovative airway device. This study has practical and clinical relevance, and the airway device
being evaluated may have the capacity to improve the quality of upper GI endoscopic procedures
in this patient group.
There are a few points which may improve the quality of the study, including:
1. Authors write: If a patient showed be in discomfort or exhibited restlessness, an additional 10
mg of propofol was given as a bolus injection and the maintenance infusion rate was increased
by 1 mg/kg/hour.
This can be subjective with varying tolerance rates among anesthesiologists. Do you agree?
How can a bias among anestheiologists be ruled out considering the differences in tolerance or
threshold among anesthesiologists? Could this be a study limitation?
2. Authors write: When the sound of airflow through secretions were found or choke occurred
during the procedure, sputum suction were recommended for immediate implementation. The
effective suction secretion and reflux was defined as that airway was patency and pulse oxygen
saturation could be promoted after suction.
Again, this is a quite subjective parameter. Is there any way of objectifying this? If not, could
this be included as a study limitation.
3. The endoscopy time was fixed at 30 minutes. Why is an endoscopy time of up to 30 minutes
important? Was it to rule out difficulties associated with longer procedure times? Is it feasible to
use the innovative device also for longer procedures such as for therapeutic procedures? Please
discuss these points, if possible.
4. The pulse oxygen saturation during endoscopy under sedation was significantly higher in
airway group (97.66%±2.96%) than in mouthpiece group (95.52%±3.84%, P < 0.001; Figure 5).
I am wondering what the clinical relevance of this marginal difference is? Could the authors
provide an insight into the clinical relevance and not only the statistical difference?
5. Propofol induction dose were significantly lower in mouthpiece group than in airway group
(P=0.042).
I understand that a higher dose of propofol is required to induce anesthesia in the airway group.
What is the clinical relevance of this, especially considering that the overall dose of propofol
was finally lower.
6. The distal end of the innovative airway is made to be set about 2 to 3 cm away from esophageal
entrance.
Could the authors include an endoscopic image or picture?
7. How does the innovative airway device affect the endoscopic examination of the
oropharyngeal space. Is there the risk of oversseing small lesions such as squamous cell cancers
in the mouth because of the device?
8. It may be of interest to understand in which coutries this device is available and which
company is producing it. Can this be mentioned?
9. Overall English language quality is good but English language editing of the manuscript
should be done before acceptance.
10. Minor point: PACU; HFNC – Please spell out abbreviation on first usage.
Thank you for giving me the opportunity to review this manuscript.