A prospective observational study to determine the efficacy of stylet angulation at the holding position during endotracheal intubation using c mac video laryngoscope in adults for elective surgery

Airway management plays an essential role in anaesthesia practice during both elective and emergency surgeries. Endotracheal intubation considered to be the gold standard in securing the airway and definitive technique for resuscitation. It is commonly performed using direct laryngoscope.

Difficulties during routine intubation in the operating room occur in 1-6% of cases and intubation failure occurs in 0.1-0.3% of cases1. Over the last few years, video laryngoscopy based on the principles of indirect laryngoscopy have been introduced into clinical practice to ease endotracheal intubation and might be especially useful in less experienced providers like junior residents and paramedics. Video laryngoscopes are equipped with better illumination of light source and camera on the tip of the blade, enabling better visualization of the airway anatomy and ultimately making it easier to visualize the entrance of larynx. C-MAC video laryngoscope, initially designed primarily as a teaching tool,may be useful device in the clinical settings also as it can be used as a standard direct laryngoscope or as an indirect laryngoscope. When used as direct laryngoscope, it functions like any Macintosh laryngoscope 6.

However, the good laryngeal view provided by the videolaryngoscopes does not always guarantee successful or easy intubation and it can be tricky and time consuming in emergency scenarios. Although gaining a view of the glottis is the easy part when using a video laryngoscope, tube delivery to the glottis is often difficult with a video laryngoscope because oral, pharyngeal and laryngeal axis are not aligned and thus the tip of the tube must pass around an acute angle to enter the larynx2. An intubating stylet is widely used to assist manipulation of the tube tip to allow necessary maneuverability to advance it beyond tation and might be especially useful in less experienced providers like junior residents and paramedics. Video laryngoscopes are equipped with better illumination of light source and camera on the tip of the blade, enabling better visualization of the airway anatomy and ultimately making it easier to visualize the entrance of larynx. C-MAC video laryngoscope, initially designed primarily as a teaching tool,may be useful device in the clinical settings also as it can be used as a standard direct laryngoscope or as an indirect laryngoscope. When used as direct laryngoscope, it functions like any Macintosh laryngoscope 6.

However, the good laryngeal view provided by the videolaryngoscopes does not always guarantee successful or easy intubation and it can be tricky and time consuming in emergency scenarios. Although gaining a view of the glottis is the easy part when using a video laryngoscope, tube delivery to the glottis is often difficult with a video laryngoscope because oral, pharyngeal and laryngeal axis are not aligned and thus the tip of the tube must pass around an acute angle to enter the larynx2. An intubating stylet is widely used to assist manipulation of the tube tip to allow necessary maneuverability to advance it beyond the glottic opening into the trachea. When angulating a stylet in the sagittal plane at the operators holding position, the holding force of the right thumb is divided into vectors in a longitudinal direction and acts on the tip of the tracheal tube by using the index finger or middle finger as a fulcrum during the entire process of placement of the endotracheal tube. Therefore, the tube tip can be efficiently and precisely operated by finger movement that is suitable for fine manipulation1.

There is knowledge lacunae whether angulating the stylet at holding position should be done routinely when performing tracheal intubation with C-MAC video laryngoscope6. Hence, in our study we would like to observe whether stylet angulation at the holding position would improve maneuverability of the tracheal tube and contribute to easy, smooth, and swift tube placement during endotracheal intubation using a C-MAC video laryngoscope.