Surgical Airway : Cricothyroidotomy

[Sacamuelas]

"The essential indication for a surgical airway is the need for an airway.

However, the usual first preference is for orotrachael intubation. (Nasotrachael intubation is slower and should be attempted only if the patient is haemodynamically stable and can be hand ventilated for long enough to obtain optimum pre-oxygenation). The hard collar may be temporarily removed if the neck is protected by in-line immobilisation. A Surgical Airway should be performed if orotrachael intubation is unsuccessful.

Situations in which a Surgical Airway should be considered as the primary method include Major Maxillo-Facialary Injury (eg compound mandibular fractures, Le Forte III Midface Fracture), Oral Burns, Fractured Larynx.

The simplest technique is needle cricothyroidotomy. This involves placing a 12 Gauge Cannula into the trachea via the cricothyroid membrane. This will allow adequate ventilation for up to 45 minutes, hypercapnea being the main limiting factor. This may buy enough time to obtain expert airway assistance and attend to other emergency procedures. (NB This is the prefered technique for children under the age of 12.)

Formal Crycothyroidotomy is the classic surgical airway. It is safer and quicker then attempting Formal Tracheostomy in the Emergency Room. The patients cervical spine is immobilised in the neutral position. A Right Handed Surgeon stands on the patient's right. The area is preped and draped. Local anaesthetic with adrenaline is used only in the conscious patient who has a patent airway. In an asphyxiated / dying patient there is insufficient time.

The thyroid cartilage is stabilised with the left hand as the right hand makes the incision. The first incision is 3cm long transverse incision through the skin overlying the crycothyroid membrane (closer to the crycoid cartilage then then the thyroid cartilage). The second pass of the scalpel is again transverse, through the crycothyroid membrane into the airway. With the scalpel blade protruding into the airway, it is rotated 90 degrees so that it is now longitudinal, holding the two edges of the incised membrane apart.

The left hand now releases the thyroid cartilage and picks up an artery forcep. The artery forcep is placed into the airway, through the exposed gap, and opened so as to take over from the scalpel as the means of holding the incised edges apart. The scalpel can now be removed and placed in the sharps tray. The right hand then picks up the endotracheal tube or tracheostomy tube and inserts it into the airway, directed towards the chest. The best size ET tube for an adult cricothyroidotomy is a size 6.0.

After confirming adequate position, the tube should be secured and suctioned. A definitive airway will be required as soon as the patient is stable, fully assessed and appropriate interventions have been performed.

Fortunately, with skilled airway doctors in most trauma centres, surgical airways are rarely required."