What would be an acceptable
anesthetic plan for this patient?
Choice of induction of general anesthesia in a
patient with a full stomach is dependent upon several factors, among which is
the patient’s airway evaluation. The airway evaluation should always include a
thorough history of the patient’s prior intubations, making certain to elicit
any his-tory of difficult intubations. If the patient has an acceptable airway,
pharmacologic prophylaxis should be administered and
preoxygenation/denitrogenation is followed by a rapid sequence induction with
cricoid pressure. At the time of induction, there should be an assistant
present to provide the cricoid pressure. Suction should be immediately
avail-able in case of regurgitation. The induction agent selected should have a
rapid predictable onset time. Commonly used agents are thiopental, propofol,
etomidate and keta-mine. The muscle relaxant used should also have a fast
onset. Classically, the neuromuscular blocking agent used for rapid sequence
inductions has been succinylcholine. If, however, succinylcholine is
contraindicated for any reason, a fast-onset intermediate-acting neuromuscular
blocking agent, such as rocuronium, can be used. When choosing these drugs, the
dose must be increased. The disadvantage of using a nondepolarizing
neuromuscular blocking agent is that its prolonged action may necessitate
prolonged mask ventilation if intubation is unsuccessful.
If intubation is unsuccessful, help from an
anesthesia col-league should be called for. Mask ventilation is initiated with
cricoid pressure. The peak airway pressures should be kept <20 cm H2O
to limit ventilation of the stomach. Ventilation should be continued until the
patient awakens. Further muscle relaxant should not be given. If mask
ventilation is difficult, ventilation through an LMA is indicated. Intubation
through a correctly seated LMA is possible. It is important to remember that
both mask ventilation and LMA placement can be impeded by cricoid pressure.
If a difficult intubation is anticipated,
either by history or physical examination, a rapid sequence induction is
contraindicated. In this case, the most prudent approach would be to do an
awake fiberoptic intubation. This poses some unique challenges in the patient
with a full stomach. For an awake fiberoptic intubation to be successful, the
patient’s airway needs to be well topicalized with local anes-thetic above and
below the vocal cords. However, anes-thetizing the entire airway, especially
below the vocal cords, will cause a profound loss of all airway reflexes and
may increase the risk of aspiration. There are those practitioners who believe
that the awake, unsedated patient will know if they are about to vomit and can
be encouraged to cough and turn their head to the side. These practitioners
will pro-ceed with topicalization of the entire airway. There are others who
will only topicalize the airway above the vocal cords in an effort to preserve
the tracheal reflexes in the event aspiration occurs. Therefore, topicalization
of the air-way is recommended for the
patient with a full stomach, but the use of a transtracheal block is user
An inhalation induction by mask should not be
done on a patient with a full stomach, except in specific circum-stances such
as a child with epiglottitis.
After the trachea has been intubated with a
cuffed endotracheal tube, the anesthetic can be maintained in a number of ways
including air/O2, inhalation agent, opioid, and muscle relaxant.
Although a cuffed tube will provide more protection than an uncuffed tube,
aspiration may still occur around the cuff.
During extubation of the trachea, aspiration
may also occur. It is thus imperative that the patient is able to protect their
airway before the trachea is extubated. Therefore, the patient should be fully
awake, responsive, and sponta-neously breathing.