**3. Routine use of VS in elective and emergency surgeries**

VL and DL have been used for decades in both elective and emergency intubations. The introduction of VL has shifted the paradigm of airway management [50]. VS was first introduced by Shikani in patients (both adults and children) undergoing routine otolaryngologic procedures [6] and has since been applied in various clinical scenarios, including difficult and emergency airway [12, 51]. The VS technique has been studied in adults in supine position [52–56], in lateral decubitus position [57], and in pediatric patients with difficult airway [30, 58]. It has also been used during awake intubation [53, 59] and for diagnostic bronchoscopy [60]. VS has also been used by emergency room physicians [61] and emergency medical technicians in the prehospital airway management [62].

#### **Figure 11.**

*Presence of mucus and saliva interfering with laryngeal views obtained by VS technique during tracheal intubation. A morbidly obese 42-year-old woman with BMI 46.6 kg/m<sup>2</sup> (165 cm, 127 kg) underwent fasciotomy and debridement. Past history included sleep apnea and snoring. LQS score grade 1. The intubation time (for demonstration) is 22 s. (Also see the Supplementary Materials Video S9).*

In 2010, VS was introduced into our department. At that time, most of our staff still used DL and some tried VL (e.g., GlideScope®) [63, 64]. We established a formal airway training course in DL, VL, and VS use for the staff and novice operators using cadaver and mannequins. Currently, we have more than 22 sets of VS from four different brands in our 21 operating rooms. Although it is not mandated to use VS, VS prevails among all the available intubating tools we have. We regularly survey the novice users and trainees to evaluate their performance and obtain feedback. Notably, VS is used in more than 90% of tracheal intubations (**Table 2**).

**Figure 12** demonstrates the routine use of VS for tracheal intubation in an elective surgery. We have previously reported on the application of VS in patients undergoing an emergency surgery during the COVID-19 pandemic [65–70] (see **Figures 13** and **14**). The coverall personal protective equipment (PPE) and plastic sheet barrier did not interfere with smooth tracheal intubation using VS in COVID-19 patients. In both clinical scenarios (**Figures 12**–**14**), VS technique provides a swift, and safe tracheal intubation, while protecting the intubating provider from secretions as he/she does not have to put his/her face close to the patient's mouth.

**Table 3** summarizes the strengths and weakness of VL and VS. The clinical performance of VS is usually evaluated in many aspects, including (1) insertion in the oropharynx; (2) visualization of the epiglottis; (3) advancement in the glottic aperture; (4) maneuverability of the stylet; and (5) adverse events such as dental trauma, soft tissues damages, autonomic overstimulation, aspiration, hypoxia, etc. In both normal airway and difficult airway scenarios, VS shows its advantages with shorter intubating time [13, 71–74], less autonomic stimulation [55], and shorter learning curve [75].

#### **Figure 12.**

*A typical case of routinely applying VS technique for tracheal intubation in elective surgery. An 89-year-old woman with BMI 25.3 kg/m2 (150 cm, 57 kg). The intubation time (from lip to trachea) is 7 s. (Also see the Supplementary Materials Video S10).*

#### **Figure 13.**

*A typical case of routinely applying VS for tracheal intubation during emergency surgery. A 26-year-old woman with BMI 21.3 kg/m<sup>2</sup> (150 cm, 48 kg) underwent an emergent orthopedic surgery due to multiple trauma during COVID-19 pandemic in 2020. Combined use of VS and a piece of plastic sheet as a protective barrier was noted. The two anesthesiologists wore PPE during tracheal intubation procedure. The anesthesia assistant was performing jaw-thrust maneuver. (Also see the Supplementary Materials Video S11).*

#### **Figure 14.**

*Same patient as in Figure 13. Close-up views from the VS video LCD screen. (A and B) Views of oropharynx and larynx. (C) Epiglottis. (D and E) Views of glottis and vocal cords. (F) Entry into trachea. The intubation time was 12 s. (Also see the Supplementary Materials Video S12).*



*the degree of relative comparison between use of VL and VS.*

#### **Table 3.**

*Comparison between videolaryngoscopes (VL) and video-assisted intubating stylet (VS).*
