From studying the utility of pulse oximetry in pediatric ED
patients in several publications since pulse oximetry was
introduced and from extensive anecdotal experience, I am a firm
believer in its utility as an additional vital sign for infants
and children with problems with a potential respiratory etiology
(eg. abdominal pain, congestion, coughing, etc.)
It works in newborns, premies, and even micropremies. We
often get referrals from general ED's because an infant's pulse
ox is 90% or so. However, when we see the patient, their pulse
ox is usually 100%. I have the following comments about pulse
oximetry in infants and children:
1. Oxygen saturation measured via pulse oximetry in very
young infants (less than 2 months), should be 99% to 100%. For
example, a pulse ox of 96% in a one month old, in my opinion,
should be investigated further. In older children, more
conventional ranges prevail.
2. Pulse oximetry measured in infants and toddlers should be
done using the band aid type probes. The clip probes are too
unreliable in this age group.
3. The wave form or the pulsation pattern of the perfusion
bar must be of "good form" (eg., steady deep pulsation, or steady
perfusion bar pulsation with good height). These pulsation
patterns correlate with reliable readings.
4. Pulse oximetry declines when patients are supine, prone,
or slouching. V/Q matching is most optinal in the upright
position. We get most of our readings with patients upright.
5. Unsteady readings, readings associated with poor perfusion
wave forms, readings in agitated patients, and/or readings with
highly variable numbers are unreliable. Without a good steady
perfusion wave form reading, nurses should be instructed in other
methods to obtain a more reliable reading (eg., have the infant
feed while getting a reading). Values should not be recorded in
the chart unless they are accurate values.
6. Please do not compare the accuracy of pulse oximetry with
tympanic thermometry. Pulse oximetry is not perfect, but it is
much more reliable than tympanic temps.
7. Ignoring an accurate pulse oximetry value is a pitfall
that should be avoided. The background information in
interpretating pulse oximetry values is modestly extensive and
beyond the scope of a note. Its interpretation by knowledgable
practitioners can be very useful. However, when oversimplifying
the interpretation of pulse oximetry (eg., merely normal value
versus abnormal value), without appreciation of its false
positive and false negative conditions, it can result in coming
to inappropriate clinical conclusions.
Loren Yamamoto, MD, MPH
Associate Professor of Pediatrics
University of Hawaii John A. Burns School of Medicine
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