Healthcare and Medicine Reference
This may occur in any unconscious patient. It is advisable to have
a functioning suction device to hand during intubation. Cricoid
pressure may prevent passive regurgitation and subsequent
This should be suspected when the oxygen saturation decreases
despite an adequate supply of oxygen. A carbon dioxide (CO 2 )
detector attached to the tube indicates correct tracheal placement
only if exhaled CO 2 persists after six ventilations. A look, listen and
feel approach should be used to recognise oesophageal placement
of the tube.
Remember: if in any doubt take the tube out!
Cervical spine injury
Excessive movement of the head and neck must be avoided in
this situation. The hard collar is removed whilst in-line manual
stabilisation of the head and neck is performed by an assistant. The
operator then intubates the airway.
Figure 15.14 Cricothyroidotomy: the cannula is placed through the
cricothyroid membrane. Redrawn from Beers MH (ed). (2006) The Merck
Manual of Diagnosis and Therapy , 18th edition. Merck & Co.
These are performed in an emergency when all possible manoeu-
vres to achieve effective ventilation and intubation have failed
and the patient's oxygen saturations are falling. Percutaneous
needle or surgical cricothyroidotomy are the immediate tech-
niques of choice.
Percutaneous needle cricothyroidotomy
This involves puncturing the cricothyroid membrane
(Figure 15.14) with a large-bore intravenous cannula attached
to a syringe.
In this technique a blade is used to pierce the cricothyroid mem-
brane. A small cuffed tracheal tube or purpose designed 4-6-mm
cuffed cannula is then passed through the membrane.
Complications of surgical airways
Trauma to surrounding structures.
Figure 15.15 An assistant applies cricoid pressure whilst the operator
Surgical emphysema due to incorrect cannula placement.
Pulmonary barotrauma: exhaled gases must be free to escape
otherwise pressure builds up within the airway.
Technique for applying cricoid pressure
Identify the cricoid cartilage immediately below the thyroid
This manoeuvre is performed to prevent gastric regurgitation with
subsequent aspiration into the lungs in the anaesthetised patient.
Digital pressure is applied to the cricoid cartilage pushing it back-
wards (Figure 15.15). This compresses the oesophagus between the
posterior aspect of the cricoid and the vertebra behind. The cricoid
is used since it is the only complete ring of cartilage in the larynx
Place the index fi nger against the cartilage in the midline, with
the thumb and middle fi nger on either side. In an awake patient,
moderate force (10 N) is applied before loss of consciousness;
the force is then increased to 30 N until the cuff of the tracheal
tube is infl ated.
The assistant should release cricoid pressure only when clearly
instructed to so by the person performing the intubation.