Comparison of Intubation Success with the Conventional Sniffing Position versus Left Head Rotation (LeHeR) Manoeuvre Using Direct Laryngoscopy in Patients with Anticipated Difficult Intubation: A Prospective, Randomized Study

Tracheal intubation is a critical, life-saving intervention. Endotracheal intubation in a challenging airway necessitates technical expertise, access to appropriate devices, and accurate evaluation of the clinical condition. Experienced as well as novice physicians or allied health professionals frequently face challenging intubation scenarios in hospital and prehospital environments. Moreover, anticipating complications related to airway management remains a challenge for anesthesiologists.

An unanticipated difficult intubation is a potentially critical situation during airway management. Many different methods have been proposed to manage this situation. In 2019, the "LeHeR" (Left Head Rotation) method was proposed to improve direct laryngoscopy in patients with unanticipated difficult laryngoscopy and intubation.

The DARES Protocol is a succinct, standardized ultrasound examination to predict difficult laryngoscopy based on upper airway measurements with the most robust data. The protocol involves only two views of the upper airway: the thyrohyoid and the suprahyoid views. Measurements selected for this protocol include the DSE, HMD, HMDR1, HMDR2, and tongue thickness, which cover all three domains of TTD, APD, and OSD.

We hypothesize that the use of the LeHeR manoeuver can improve the visualization of vocal cords and improve the chances of successful endotracheal intubation in patients with anticipated difficult intubation as defined by DARES protocol. Thus, we plan to compare the conventional sniffing position with the LeHeR manoeuvre in adult patients with anticipated difficult intubation.