Efficacy of a direct wire-guided intubation system to secure tracheal intubation: A prospective observational study

Tracheal intubation over a flexible guide is an essential skill for those managing difficult airways in anaesthesia and critical care. However, there may be difficulty railroading the tube over the guide due to impingement of the tube bevel entering the larynx. This may lead to repeated intubation attempts, possible trauma, possible failed intubation and hypoxia if alternative ventilation is not ensured. In this prospective observational study, we investigated the effectiveness of tracheal intubation without impingement over a guidewire already in place. Our direct wire-guided intubation system consists of a modified reinforced silicone tracheal tube with a guide channel in its wall to accommodate a matched kink-resistant guidewire as the introducer. We studied 299 American Society of Anesthesiologists Physical Status classification 1-3 patients with a predicted low risk of difficult intubation. Significant impingement occurred in one patient due to a deep laryngeal fissure (0.3%, upper limit of 95% confidence interval 1.9%). Laryngeal tube transit was graded 'not difficult' in 284 patients (95%), and 'mildly difficult' in 14 (4.7%). Tube transit between oropharynx and glottis offered no resistance in 294 patients (98.3%) and mild resistance in five (1.7%). There were no oesophageal misplacements of the tube. Our system appears effective to facilitate guidewire-assisted tracheal intubation in patients at predicted low risk of difficult intubation when a guidewire is already in place. Further studies are required in patients with predicted difficult intubation.