Airway management is an essential skill in anesthesia. Most anesthesia related complications are due to inadequate airway management. Obese patients are special group that have increased risk of airway management adverse events. This group of patients is increased in number. Airway management is an interesting area of research for every anesthesia provider. Patient position during intubation came in light recently. I think it is mandatory to have solid scientific evidence in that topic. So, I am glad to read your manuscript. Study title is informative and represents research work. Abstract gives concise and brief description about the study. In the introduction, you give good idea about the problem. You explain deficiency of evidence. Aim of the study is clearly settled. I appreciate your clear presentation of study outcomes. But, I have some comments to methods that need explanation: 1) You excluded patients with limited neck extension. In patients with BMI more than 35kg/me I think they will have some limitation in neck mobility. 2) You may better use neck circumflex as better index for obesity. 3) With neck extension, I think neck pain postoperatively should be evaluated and recorded. I want to ask if you mentain that position during surgery. 4) Airway assessment is usually performed in pre-anesthetic visit, you may have different protocol. 5) Operator expertise is a critical indicator for intubation success, which need to be clearly mentioned. 6) End tidal co2 monitoring is better started after induction and during mask ventilation. 7) Technique of mask ventilation should be clarified eg. Two hands CE, two hand jaw thrust. 8) Inadequacy of mask ventilation should be clearly explained by adequate tidal volume. 9) I found it is better to use (external laryngeal manipulation) rather than (cricoid pressure). You better explain in methods section. 10) In your pilot study, you found incidence of difficult laryngoscopy is 80%%. I think it is much especially with experienced hands. In result section incidence of difficult laryngoscopy in control group was 47% only. This may affect sample size calculation. In results, you had 4 patients with mallampati score 4, I think those patients should have a chance for awake intubation. Difference between both groups is clinically significant, that your technique should have a try. Short time to endotracheal intubation in both groups indicates experience of operator. It also explains absence of hypoxia in both groups. In number of intubation attempts I want to see patients with more than one attempt, which has clinical significance. In discussion section, authors discuss their results, and explained implications on clinical practice. Study conclusion answers the aim of the research work. It's supported by study results. I suggest discussing role of head elevation on oxygenation especially on obese patients as they have limited functional residual capacity. Factors of rapid desaturation in those groups of patients should have been discussed. Limitation I suggest adding absence of radiological studying as limitation of the study. Use of video laryngoscope is emerging tool in management of difficult airway. You may have different results with its use. References are recent, relevant and include key references in the topic.

Decision Accepted after minor changes