Mechanical Monitoring

Mechanical Monitoring

In addition to standard pulse oximetry and cardiac
monitoring,6,10,11 capnography is being increasingly
recommended during procedural sedation and analgesia because
this continuous assessment of ventilation provides the earliest
indication of respiratory compromise, especially central and
obstructive apnea.88,89
Potential Adverse Effects
The ketamine literature in children is robust enough to
support fairly reliable estimates of the frequency of specific
adverse events, as detailed further in this section. This is not yet
possible in adults; however, their experience can be predicted to
roughly parallel that of children unless contrary evidence is cited
below.
In the large meta-analysis, airway or respiratory
complications were observed in 3.9% of children overall,
including transient laryngospasm in 0.3% and transient apnea
in 0.8%.2,3 Misalignment of the airway may occur at any time
during dissociative sedation, and stridor or hypoxemia should be
initially treated with airway repositioning.4,19,71
Laryngospasm. The large meta-analysis showed no
association of laryngospasm with any clinical factors, except a
slightly greater risk with unusually high IV doses.2,3,20 A casecontrol
analysis found no association of age, dose,
oropharyngeal procedure, underlying physical illness, route, or
coadministered anticholinergics.90 As discussed in the
“Contraindications” section, upper respiratory infection and
active pulmonary disease (including asthma) have been
considered risk factors for laryngospasm according to
extrapolation from inhalational anesthesia research.4,12,16,33,91

Ketamine-associated laryngospasm is rare (0.3% in a large
meta-analysis2), and the evidence supports it as largely

idiosyncratic. However, clinicians administering ketamine must
be prepared to rapidly identify and manage this adverse event.
Although some patients may require bag-valve-mask ventilation,
tracheal intubation because of ketamine-associated
laryngospasm is rare.4,42
Respiratory depression. Respiratory depression and apnea
are unusual with ketamine and are transient when they do
occur. Although most commonly associated with rapid IV
administration, they can rarely occur with the IM route. When
respiratory depression is noticed, it is invariably at the time of
peak central nervous system levels (ie, 1 to 2 minutes after IV
administration or 4 to 5 minutes after IM
administration).