Another technique is to instill lignocaine directly on the vocal cords by a syringe and needle through the cricothyroid membrane
. This membrane is marked by a shallow depression in between the cricoid and thyroid cartilages.
To create a surgical airway (cricothyroidotomy) without the usual instruments, physicians can use a knife or other sharp object to make a vertical incision in the skin over the cricothyroid membrane
The scalpel technique was performed as follows: 1) Identification of the cricothyroid space followed by transverse skin incision using a number 15 scalpel blade; 2) Palpation of the cricothyroid membrane
(CTM) followed by transverse incision through the CTM using the same scalpel blade; 3) Insertion of a 6.0 mm ID cuffed endotracheal tube (Portex, Blueline, UK) with the help of a tracheal dilator or using the scalpel blade handle to keep the incision open.
(4,5,8,9,11) A number of user-friendly cricothyrotomy kits are available on the market, but in the absence thereof surgical cricothyrotomy is possibly the most effective alternative (stab incision of skin and cricothyroid membrane
and placement of a cuffed ID 5.0 mm ET tube).
Firstly, it might be difficult to identify the cricothyroid membrane
correctly, especially in patients who have sustained trauma to their larynx.
In transtracheal jet ventilation, a 12 to 14-gauge IV catheter is placed into the cricothyroid membrane
and high-pressure oxygen is delivered to the patient.
The procedure entailed injecting Zyplast X-linked collagen through a 25- or 27-gauge needle advanced under nasopharyngoscopic guidance percutaneously through the cricothyroid membrane
into the true vocal cords.
In neonates, the cricothyroid membrane
(CTM) has a mean length of only 2.6[+ or -]0.7 mm and a width of 3[+ or -]0.63 mm.
Contraindications for use are: on-going coagulopathy, obscure cricothyroid anatomy, infection of cricothyroid membrane
After sterile preparation, we palpate the thyroid cartilage and identify the cricothyroid membrane
. The skin is then anaesthetised with a 25-gauge needle.