Sugammadex in anaphylaxis. A case–control study?

Platt et al. make some interesting observations regarding the use of sugammadex in the context of anaphylaxis, whether it is rocuronium triggered or not 1, acknowledging the lack of existing evidence and practical difficulties of obtaining it. I would like the authors to clarify the question they were seeking to answer in their paper. They state that they wanted to compare cases treated with sugammadex and subsequently confirmed to be triggered by rocuronium, with those that were not. However, they draw the conclusion that sugammadex cannot be relied upon as an effective treatment in anaphylaxis and does not modify the immunological cascade of a suspected hypersensitivity reaction. Do the authors consider that their study was adequately designed to either confirm or refute this? Secondly, I question the rigor of the peer review process for the paper. It is clearly stated in the title that this is a case-control study, although the method used is far from that of a case-control study. Indeed, there has been no search and selection of cases to use as controls. Those presumed to be controls are a subset of those identified while searching for cases. This is unfortunate, as a well designed, case-control study would have been a very appropriate methodology (providing one of the higher levels of evidence achievable) to gather evidence on the use of sugammadex in suspected anaphylaxis due to rocuronium, given the low frequency of cases. Have the authors considered identifying a group of suitable controls and using that as a comparison for the cases already identified? Nevertheless, this case series provides interesting reading in the run up to the imminent NAP6 study on peri-operative anaphylaxis.