12
• When the mask is in place, resistance will be felt.
• After insertion ensure lips are not trapped between
patient tube and teeth to avoid trauma to lips.
INSERTION PROBLEMS
• For pediatric patients, a partial rotational technique
is recommended in case of placement difficulties.
• Coughing and breath-holding during Ambu
AuraOnce insertion indicates inadequate depth
of anesthesia – Immediately deepen anesthesia
with inhalational or intravenous agents and initiate
manual ventilation.
• If you cannot open the patient’s mouth sufficiently
to insert the mask, check that the patient is
adequately anesthetized. Ask an assistant to pull
the jaw downwards thus making it easier to see into
the mouth and verify the position of the mask.
• For difficulty in maneuvering the angle at the back
of the tongue when inserting AuraOnce, press the
tip against the palate throughout or else the tip
may fold on itself or meet an irregularity in the
posterior pharynx, e.g., hypertrophied tonsils.
Should the cuff fail to flatten or begin to curl over
as it is inserted, withdraw the mask and reinsert
it. In case of tonsillar obstruction, a diagonal
movement of the mask is recommended.
3.4. Fixation
If deemed necessary, secure AuraOnce to the patient’s
face with adhesive tape or with a mechanical tube
holder suited for this purpose. 7 It is recommended
to use a gauze bite block.
3.5. Inflation
• Without holding the tube, inflate the cuff with just
enough air to obtain a seal, equivalent to intracuff
pressures of a maximum of 60 cmH₂O. 6 Often
only half of the maximum volume is sufficient to
achieve a seal – please refer to Table 1 for maximum
intracuff volumes.
• Monitor the cuff pressure continuously during the
surgical procedure with a cuff pressure gauge. This
is especially important during prolonged use or
when nitrous oxide gases are used.
• Look for the following signs of correct placement:
The possible slight outward movement of the tube
upon cuff inflation, the presence of a smooth oval
swelling in the neck around the thyroid and cricoid
area, or no cuff visible in the oral cavity.
• The mask may leak slightly for the first three or four
breaths before settling into position in the pharynx.
In case leakage persists, check that there is adequate
depth of anesthesia and that the pulmonary inflation
pressures are low before assuming that reinsertion
of AuraOnce is necessary.
3.6. Verification of correct position
• Correct placement should produce a leak-free seal
against the glottis with the tip of the cuff at the
upper oesophageal sphincter.
• The vertical line on the patient tube should be
oriented anteriorly towards the patient’s nose.
• AuraOnce is inserted correctly when the patient’s
incisors are between the two horizontal lines on the
patient tube. 2, item 5. Reposition the mask if the
patient’s incisors are outside this range.
• The position of AuraOnce can be assessed by
capnography, by observation of changes in tidal
volume (e.g., a reduction in expired tidal volume),
by auscultating bilateral breath sounds and an
absence of sounds over the epigastrium and/or by
observing chest rise with ventilation. If you suspect
that AuraOnce has been positioned incorrectly,
remove and reinsert – and ensure that anesthetic
depth is adequate.
• Visual confirmation of anatomically correct position
is recommended, e.g., by using a flexible scope.
UNEXPECTED REGURGITATION
• Regurgitation may be caused by inadequate
level of anesthesia. The first signs of regurgitation
may be spontaneous breathing, coughing or
breath-holding.