Comparison of supraglottic devices i-gel(®) and LMA Fastrach(®) as conduit for endotracheal intubation.

Sir,

We read the article by Kapoor et al. comparing i-gel® and LMA Fastrach® as conduit for endotracheal intubation with great interest.[1] However, we would like to point out few issues that need clarification.

There is no mention of the technique used for randomization that is considered the heart of any randomized controlled trial. The ‘chit’ method as highlighted by the authors seems to be a surrogate of ‘closed envelope technique’ and is meant for allocation concealment but not for randomization.[2] The basis of the sample size calculation is not clear. The authors have only mentioned the effect size (10%), the alpha error and the power of the study without describing the presumed baseline success rate of intubation with LMA Fastrach®. It is difficult to calculate the sample size in the absence of the baseline success rate of intubation with LMA Fastrach®. If one assumes, the baseline success rate to be 74% (as per the final result of this study), with an effect size of 10% and keeping the power and the alpha error same, then the desired sample size turns out to be 1318 subjects with 659 in each arm. If one tries to calculate the power of the current study with a sample size of 100 patients, then it turns out to be 23%.[3] The power further reduces to only 14% with the sample size of 50 subjects as estimated by the authors. There is no mention about the principle used for the analysis that is, whether it was ‘intention to treat’ or not.

Despite these, we appreciate the authors for their work for generating new evidence in the field of managing difficult intubation and ventilation with supraglottic airway devices.