A randomized comparison of videolaryngoscope GlideScope Titanium with videolaryngoscope KingVision (non-channeled blade) for nasotracheal intubation in patients with predicted difficult airway scheduled for maxillofacial procedure

Introduction or objective: After the publication of the results of our retrospective cohort study (King Vision™ videolaryngoscope for nasal intubation in predicted difficult airway due to maxillofacial emergencies; doi: 10.1097/EJA.0000000000001173), we designed a prospective randomized study comparing the King Vision videolaryngoscope and Glidescope Titanium for nasotracheal intubation in patients indicated for maxillofacial surgery. Material and methods: Our single‐center, prospective randomized study was approved by the Ethics Committee of General University Hospital (no. 1597/17 S‐IV). The study was registered on www.anzctr. org.au (ACTRN12618000401257). We compared the intubation time between the videolaryngoscope Glidescope Titanium® (Verathon Inc., Seattle, WA, USA) with the videolaryngoscope VL King Vision® (Ambu Ltd., Copenhagen, Denmark) with a disposable non‐channeled blade for primary nasotracheal intubation. Study participants were adult patients between 18–90 years of age, both genders, American Society of Anesthesiologists (ASA) physical status I‐III scheduled for a procedure of maxillofacial surgery with one or more predictors of difficult intubation. Exclusion criteria were interincisional distance lesser than 2 cm, a history of a difficult airway with the need for fibreoptic intubation. Results: Sample size analysis was performed using the results of the previously published study with a power of 0.8 and alpha level of 0.05 [1]. For the study we screened 158 patients. In total, 110 patients were enrolled, 55 in each group. Demographic data and preoperative airway assessment are reported in Table 1. The primary outcome of our study was a time of intubation (interval between discontinuation of bag‐mask ventilation to the first successful gas exchange displayed on the capnographic curve). No statistically significant difference between the groups was found (p=0.77) There were two failures to intubate, one in each group, one patient was woken up and intubated with the flexible fibrescope and the second one was intubated orally. Amongst the secondary outcomes was only one statistically significant result. That was the quality of visualization of the laryngeal inlet (Cormack–Lehane classification) [2]. Superior visualization was in the Glidescope group. All results are listed in Table 2. Discussion and conclusion: Videolaryngoscopy became an integral part of difficult airway algorithms [3]. The KingVision videolaryngoscope is a portable device that was introduced to clinical practice in 2014. Only a few studies evaluated this videolaryngoscope in a normal or simulated difficult airway. Therefore we compared KingVision videolaryngoscope with Glidescope videolaryngoscope, later on with the available studies for use in the difficult airway. The results of our study showed that both videolaryngoscopes may provide similar and safe conditions for nasotracheal tube placement. The only statistically significant difference was the quality of visualization of the vocal cords with the Glidescope, which was most likely caused by a special angulated laryngoscopic blade. There were several limitations of our study design. The type of videolaryngoscope could not have been blinded for the operators. Another limitation we need to be aware of was that all patients were intubated by highly experienced anesthesiologists. Therefore, the results could differ for less experienced operators. Based on the results of our study we can conclude, that the Glidescope videolaryngoscope and the KingVision videolaryngoscope with a disposable non‐channelled blade are both safe to use in the difficult airway in maxillofacial surgery.