Retrograde Laryngeal Block: A New Technique for Awake Intubation Compared With Conventional Regional Airway Block

Introduction: Retrograde laryngeal block is a new technique that blocks complete supraglottic and glottic area by introducing catheter retrograde from trachea to these regions. Methods and Materials: This is a clinical trial conducted on two groups each containing 15 patients, who were candidate for awake intubation. The first group (A) underwent conventional method of airway block, by multiple injections of local anesthetic. The second group (B) underwent retrograde laryngeal block as a new method of regional airway anesthesia. In this method the catheter is inserted from cricothyriod membrane through a flexible guide wire, and then local anesthetic drug will be administered by direct vision of tip of the catheter by employing glide scope. The catheter has three separate orifices; each will stay on distinct area of either supraglottic and glottis area which can be adjusted at any level through this area that is considered to be blocked. Result: Both groups had hemodynamic stability during performing block. In group A we had two incidences of laryngospasm due to pain of multiple needle insertion; in group B we had no incidence of laryngospasm (P=0.1). In group A we had 5 patients with partial airway block which needed further intervention during awake intubation but in group B all the cases had complete and perfect airway block (P=0.001). Patients comfort was better in group B with single injection than group A with multiple injections (P=0.005). Discussion: The advantage of this method is single injection and high quality of block performance in comparison with the other technique. It can be conducted for the patients with neck pathologies that make conventional airway block impossible. Conclusion: This method can be applied in patients with neck pathologies that make conventional block impossible.