*7.1.1 Stylets*

*Special Considerations in Human Airway Management*

**6.3 Plan C. Awakening or total paralysis**

**6.4 Plan D. Front neck emergency access (FONA)**

proceed to Plan B.

**6.2 Plan B. SAD**

to Plan C.

obstruction [17, 21].

with repeated practice [24, 25].

subsequent attempt [18–20]. Repeated attempts at tracheal intubation reduce the likelihood of effective airway rescue with SAD [21]. Current guidelines recommend a maximum of three intubation attempts; a fourth attempt can be done by a more experienced colleague. If unsuccessful, a failed intubation should be stated and

Maintaining of oxygenation: supraglottic airway device (SAD) insertion is in the guidelines. The emphasis of Plan B is to maintain oxygenation using a SAD. If we succeed in the placement of a SAD, it brings the opportunity to stop and consider whether to wake the patient, try a new attempt at intubation, continue without a tracheal tube, or, in rare cases, proceed to a cricothyroidotomy. If we cannot achieve oxygenation via SAD after a maximum of three attempts, proceed

Final attempt at mask ventilation. If effective ventilation has not been established after three attempts at SAD insertion, Plan C proceeds directly. At this stage, several possible scenarios can be developed. During Plans A and B, it will be determined whether mask ventilation was easy, difficult, or impossible, but the situation may have changed if attempts at intubation and SAD placement have traumatized the airway. If mask ventilation results in inadequate oxygenation, the patient should be awakened in all but exceptional circumstances, and this situation will require total antagonism of the neuromuscular block. If oxygenation cannot be maintained using a face-mask, ensuring complete paralysis before critical hypoxia develops and we will have one last chance to rescue the airway without resorting to Plan D. Sugammadex has been used to antagonize neuromuscular block during the situation of CICO, but does not guarantee a patent and manageable upper airway. Residual neuro-depressant medication, airway laceration, or pre-existing upper airway disease may contribute to airway

A CICO situation arises when attempts to manage the airway by tracheal intubation, mask ventilation, and SAD have failed. Hypoxic brain damage and death can occur if the situation is not resolved quickly. NAP4 report provided feedback on a cohort of emergency surgical airway and cannula cricothyroidotomies performed when other methods of securing the airway had failed [22, 23]. The report highlighted several issues, including decision making (delayed progression to cricothyroidotomy), knowledge gaps (not understanding how the available equipment worked), system failures (specific equipment not available), and technical failures (not placing a cannula in the airway). After NAP4, the discussion focused largely on the choice of technique and equipment used when airway rescue failed, but the report also highlighted the importance of human factors (discussed elsewhere) [16, 17]. Regular training in technical and non-technical elements is needed to reinforce and retain skills. Success depends on decision-making, planning, preparation, and skill acquisition, all of which can be developed and refined

FONA consists of surgical airway access employing an emergency cricothyroid-

otomy. This technique is presented and discussed elsewhere in this book.

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We define the classic stylet as a malleable metal wire designed to be inserted into the endotracheal tube to facilitate tracheal placement at the time of intubation with difficult laryngoscopy. Mild mucosal bleeding and a sore throat are complications associated with stylets (**Figure 1**).

**Figure 1.** *Classical stylets.*

We can find several commercialized types that differ in curvature and size. There are also specialized stylets available known as endotracheal tube introducers or "rubber elastic plug" which consist of a 50 to 60 cm stylet with the distal tip bent at a 30-degree angle. They are indicated in a grade III Cormack-Lehane view because they allow the physician to direct forward under the epiglottis and through the vocal cords and then a tracheal tube can be inserted over it. Some of them are single-use like **Frova,** whose tip is fenestrated to allow oxygenation. However, Eschmann introducer can be sterilized and reused [26].

Today there are also disposable optical lighted stylets or light wands that incorporate a video or fiber-optic display element at the distal end. The viewing element provides the clinician with an adequate view from outside the mouth with direct laryngoscopy to the region near the glottis. Common examples include; the **Clarus video system**, the **Shikani video system**, the **Bonfires retromolar intubation fibrescope**, and the **Leviton FPS telescope** (**Table 4**) [27, 28]. They are not indicated for use in patients with laryngeal trauma, tumors, and foreign bodies. It is also not indicated for patients with thick necks or limited neck extension.

Instructions for use [28]:

Introduce the ET over the stylet having previously lubricated the inner face of the ET. Choose the desired stylet angle. Using the index finger of the left hand or the laryngoscope, move the tongue to the left and insert the tip of the pencil into the right side of the mouth with the right hand. Try to direct the tip of the stylet towards the midline of the neck trying to pass the glottis. Once the tip of the stylet passes the glottis, we will appreciate light in the midline of the neck by transillumination. We then advance the ETT through the stylet to the trachea.


**Table 4.** *Stylets.*
