Healthcare and Medicine Reference
Box 15.4 Causes of diffi cult intubation
Diffi culty inserting the laryngoscope (e.g. reduced mouth
Reduced neck mobility (e.g. rheumatoid arthritis).
Airway pathology (e.g. tumours).
Congenital conditions (e.g. Pierre Robin sequence, Marfan's
Normal anatomical variants (e.g. protruding teeth, small mouth,
Figure 15.12 View of vocal cords at laryngoscopy.
Box 15.5 Strategies for diffi cult intubation
Adjust position of patient: optimise head and neck
Box 15.3 Endotracheal tube position confi rmation
Airway manoeuvres such as BURP (backward, upward and
• look, listen and feel
approach. An end-tidal CO 2 monitor will confi rm the presence in
Correct tube position is confi rmed with the
to the patient's right) may optimise the view by applying
manipulation to the thyroid cartilage.
Alternative laryngoscopes (e.g. straight blade, short
• for adequate chest movement.
Intubation aids: gum elastic bougie or intubating stylet.
for breath sounds over the precordium.
for chest expansion.
Intubation through a laryngeal mask.
Remember: if in any doubt take the tube out!
Surgical airway (e.g. cricothyroidotomy).
Remember that repeated attempts at intubation should be
avoided. Patients die from failure to oxygenate rather than
failure to intubate.
Figure 15.13 Cormack and Lehane classifi cation of view at laryngoscopy.
Grade I full view of vocal cords. Grade II partial view of vocal cords.
Grade III only epiglottis seen. Grade IV epiglottis not seen. Grades III and IV
are termed diffi cult.
view of the vocal cords at laryngoscopy (Figure 15.13). It is, how-
ever, possible to have a good view of the cords at laryngoscopy but
still have problems passing the endotracheal tube itself through the
airway and past the vocal cords. Causes of diffi cult intubation can
be found in Box 15.4 and a list of strategies for diffi cult intubation
in Box 15.5.
Introduce the tube through the right side of the mouth. It is
helpful to have an assistant pull on the right-hand corner of the
mouth to give an improved view.
Advance the tube keeping the larynx in view until the cuff
Potential problems during intubation
Certain features of a patient's anatomy might make intubation dif-
fi cult. In these cases it is essential to ensure adequate oxygenation
rather than persisting with intubation attempts.
is positioned below the cords (Figure 15.11c). It is usually
advanced to a depth of 23 cm at the incisors in an adult male
and 21 cm in an adult female.
The tube is then connected to a means of ventilation such as a
bag-valve-mask, a portable ventilator or an anaesthetic machine.
Infl ate the cuff; the cuff should be infl ated using a 20-mL syringe
with room air. The cuff should be infl ated until no leak around
the cuff occurs with positive pressure ventilation.
Confi rm the position of the tube, using a look, listen and feel
Intubation is a potent stimulus to both the respiratory and
cardiovascular systems. It must only be performed in the deeply
unconscious patient. Respiratory effects include increased respira-
tory drive, laryngospasm and bronchospasm. Cardiovascular effects
include tachycardia, hypertension and dysrhythmias.
approach (Box 15.3).
Secure the endotracheal tube using a tie or bandage
Diffi culty with intubation
Dental and soft tissue damage can occur. This can be minimised by
skilled intubation technique.
This can be predicted or completely unanticipated. A widely
accepted classifi cation of diffi culty of intubation is related to the