A prospective randomized trial to assess the effectiveness of Coseal to seal air leaks in lung surgery

Abstract

We read with great interest the article by Tan et al .[ 1] assessing the efficacy of the Coseal surgical sealant in the treatment of air leaks after lung surgery, and we congratulate the authors for the scientific quality of their study. The results of this paper are conflicting with those reported in our recent randomized trial [2, 3], since they do not report any benefit in intra- and postoperative air leak control related to the use of the sealant, although the design of the two studies appears to be similar at first glance. As pointed out by the authors, there are two main differences in the methods of our study that potentially might have had an impact on results. They include: (i) the use of bovine pericardial strip reinforcement of the staplers employed for division of incomplete fissures and (ii) the exclusion of patients with mild (Grade 1) intraoperative air leaks. Since mild air leaks usually have a rapid spontaneous resolution, the inclusion in each study group of the trial by Tan, of more than 40% of patients presenting Grade 1 air leaks, may represent a factor influencing the results that could justify some differences with our study. Our trial has been performed on a statistical sample of >100 patients with moderate/severe air leaks for each group, while only 33–34 patients for each group in the English trial presented moderate or severe air leaks. Based on this data, it could be hypothesized that the benefit related to the application of the sealant is more likely in patients with higher severity of air leaks, in which a rapid spontaneous resolution is harder to be obtained. A further comment has to be said concerning the dose of product applied in each patient. In the English trial, no additional application over the standard dose (4 ml) has been reported after the first submersion test. In our study, some patients in the Coseal group received a double volume of sealant due to the presence of large sites of air leaks to be treated. In our previous experience with the sealant, we have observed that, in cases with multiple air leak sites treated with the division of the standard quantity of sealant in smaller doses for each parenchymal area, reappearance of air leak after initial postoperative evidence of air tightness may occur. This finding may suggest the need for an increase of the sealant dose when larger or multiple sites of air leaks are present. This aspect could have an impact on the results and, in our opinion, should be taken into account when assessing the efficacy of the sealant.