Hypothesis and experimental approach
Based on the data available to date, it can be assumed that VAL is at least equivalent to direct laryngoscopy also in the context of elective intubations but could increase patient safety in special situations. Therefore, this trial implements a three-arm, parallel group, randomized-controlled design to investigate the hypothesis that VAL is primarily non-inferior to conventional laryngoscopy in terms of the rate of successful intubations at first attempt. In this study, patients are randomized to one of three parallel study arms: in the first arm, the patient is primarily intubated using conventional, direct laryngoscopy with a Macintosh blade. This intervention, thus far considered the gold standard, also represents the control group. In a second arm, patients will be intubated by VAL, also using a Macintosh-shaped blade. In the third study arm, the primary instrument to be used will be a video-assisted laryngoscope, where primarily and regardless of possibly known difficult airway, a hyper-angulated blade will be used.We hypothesize that the procedure “video-assisted laryngoscopy”, i.e. both VAL study arms taken together in a first analysis step, is non-inferior to the “conventional laryngoscopy” control group regarding the primary endpoint “successful intubation at first attempt”. If this first attempt fails, the decision on the laryngoscopy procedure to be used in the further course is the sole responsibility of the anaesthesiologist performing the procedure; for reasons of patient safety, the study protocol does not contain any provisions in this regard, and the procedure primarily used according to randomization can be abandoned without consequence for study participation.