Response to ‘Blind intubation via a supraglottic airway device in the prone patient: Some concerns’

Colleagues Feeley and O’Rathallaigh have expressed their concerns regarding our study.^1,2 It is clear that the authors are advocates of patient safety, which is applaudable. They raised three concerns and concluded that our study design was harmful to patients. We believe that much of their concerns is a continuation of the ethics in airway research debate.^3,4 In short, many agree that manikins are not a reliable model for clinical airway management and research in patients is required. However, because this research carries risks, guidelines were proposed to allow airway research in patients while reducing the risks of such studies. These guidelines are considered controversial and no consensus has been reached so far. ⁵ We would like to express our point of view regarding the concerns with our study, without commenting on the ongoing debate regarding ethics in airway management research.

In our study, up to three airway manipulations were allowed for study purposes. As some anaesthesiologists in our institution routinely use an i-gel® (Intersurgical Ltd, Wokingham, Berkshire, UK) for airway management in the prone position, the insertion of the i-gel and the choice to exchange the i-gel for an endotracheal tube after the study intervention was part of routine care.^6,7

Obviously, multiple airway manipulations may risk airway trauma, although one must consider the scenario from which this statement originates. The NAP4 data are based on clinical situations, for instance when one is suddenly confronted with a difficult intubation, multiple attempts are required and stress by the physician may lead to applying more force for airway management. Such a situation is not applicable to our study, in which: (a) patients with signs of a difficult airway were excluded; (b) successful ventilation using an i-gel was required for subsequent intubation attempts; (c) an experienced anaesthesiologist performed the intubations to prevent too much force from being applied; (d) a camera-embedded tube was used to prevent airway damage or detect bleeding; and (e) patients could readily be turned for supine airway management. These safety measures made us believe that three attempts for intubation were sufficiently safe to perform. Clearly, no study is without risks, including our study. We only argue that the risks were sufficiently minimised.

2. Indeed, to our knowledge, the use of an i-gel as an intubation conduit has only been studied in the supine position, as we have stated in the paper. As the concept of using an i-gel as an intubation conduit has already been investigated, we see little additional value of a manikin study in the prone position of which the reliability as a model is questionable.

3. The endotracheal tube was substituted with a VivaSight-SL tube (Ambu A/S, Ballerup, Denmark) as a safety measure for the study. As mentioned in the paper and limitations, we expect that these results are transferable to the use of regular endotracheal tubes, which are commonly available. We specifically warn against the statement that a fibreoptic bronchoscope is available within seconds in a modern operating theatre or in the intensive care unit. We believe that this is a grave underestimation of the required time.

We believe that we have the same goal as Feeley and O’Rathallaigh, which is performing safe anaesthesia for all patients. This includes patients who lose their airway in the prone position. Because of patient studies, with sufficient safety measures, these patients will benefit from science rather than suffer from poorly transferable manikin studies. We disagree with their comment that we have failed to do no harm. We expect that the debate regarding the risks for study subjects will continue.