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#4 Laryngospastic Reflex
While the gag reflex is often initiated more anatomically
superior and in the oral cavity, the protective Laryngo-
spastic Reflex is most often initiated posteriorly in the
endolarynx at the vocal cord level and initiates a much
more violent, exaggerated, prolonged, and life-threatening
closure response. The superior laryngeal nerve mediates
the vocal cord closure during laryngospasm events. In
severe laryngospasm events, closure may involve the entire
epiglottic body, obscuring the true cords, and is a key
difference in glottal closure seen during the Gag Reflex.
In a dental setting, it is most often seen concurrently in
a sedated patient where poor surgical field control has
allowed saliva, water irrigation, blood, or other surgical
debris to slip down the throat. Though its activation is
airway protective, in most instances the Laryngospastic
Reflex seen in the sedated patient needs provider interven-
tion to be stopped in order to regain proper oxygen levels
to the patient. This is in opposition to the glottal closure
seen in the Gag Reflex which usually involves a conscious
patient and the closure is self-limiting to the noxious event.
Another key difference is the purpose between the two
cord closures. Where vocal cord closure during the Gag
Reflex is in preparation to forceful exhalation to launch
debris away from the cords, the Laryngospastic Reflex
purpose is to halt debris progression into the trachea,
but may not necessarily be followed by forceful exhala-
tion. Persistence of the Laryngospastic Reflex without
intervention may result in hypoxemia, hypercapnia, and
body systems injury. Interestingly, patients undergoing
increasing levels of sedatives during a dental procedure
will experience reduced airway protective reflexes, with
the exception of the Laryngospastic Reflex with concur-
rent breathing cessation, or apnea. In a study conducted
by Tagaito, et. al., when all other protective airway mecha-
nisms are diminished, the laryngospasm replaces these
diminished reflexes as the primary protector.
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This reflex
can be abolished, but the sedative concentrations needed
to do so will require the patient’s airway to be expertly
managed.
Laryngospasms are actually a common occurrence in
non-sedate persons. A person who swallows a drink too
quickly while holding a conversation or inhaling concur-
rently has experienced the Laryngospastic Reflex followed
by the Cough Reflex. The first reflex halts the liquids
intrusion into the trachea, the latter reflex quickly expels
the liquid away from the glottal opening. Recovery is most
often very rapid, followed by the person stating, “Oh,
it went down the wrong pipe.” However, in a sedated
patient, laryngospasms can be a life-threatening occur-
rence. As stated earlier, laryngospasms increase when
other reflexes are blunted, combine this sedation fact
with the fact that a dental provider is performing surgical
procedures in a shared space and the risk of complications
increases. The management for a laryngospasm are first
to clear the airway of any dental materials, next suction
the airway, possibly with a yankauer suction to reach the
glottal opening, perform a head-tilt chin lift, and apply
a bag valve mask (BVM) using positive pressure ventila-
tion (PPV) to force air into the airway and pop the vocal
cords open. Effective PPV may require the placement
of an advanced airway device. These maneuvers are not
second nature and require training and practice to be
successful in a rescue situation. If these maneuvers fail,
pharmacological intervention may be needed and should
only be administered by proficiently trained individuals.
#5 Swallow reflex
In opposition to the Laryngospastic Reflex’s more urgent,
brutish action for protection, The Swallow Reflex, also
referred to as the Palatal Reflex or Deglutition Reflex, is
one of the more gracefully fluid protective reflexes. Coor-
dination of the tongue, pharynx, and epiglottis direct
food stuffs and saliva into the esophagus. Movement of
material toward the posterior of the oral cavity is volun-
tary, but the airway protective reflex initiated the moment
of pharyngeal proprioceptive stimulation when intrusions
are not or cannot be expelled out of the mouth is invol-
untary. In these instances, the body makes an autonomic
decision as to how best protect the airway. Failure of the
Swallow Reflex would allow materials harmful to the
lower airways, structures past the glottal opening, to expe-
rience blockage that would result in choking or pulmo-
nary aspiration. At the time of the unexpected intrusion,
such as dropping a dental crown down the airway, touch
receptors in the soft palate and oropharynx fire, begin-
ning the Swallow Reflex which originates in the medulla
oblongata and pons located in the hindbrain and brain
stem. The neuronal pathway for this reflex is complex,
involving the trigeminal (V), facial (VII), glossopharyn-
geal (IX), vagus (X), accessory (XI) and hypoglossal (XII)
nerves. With such complex synchronization, the Cough
Reflex, the Vomit Reflex, and breathing is momentarily
halted while the Swallow Reflex is in action.
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continues
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