In this study of 12 term gestation infants, approximately
5 to 9 weeks of age, the gradient and relationship between
abdominal skin temperature and axillary temperature were
highly variable within individual subjects. While the mean
difference between temperatures was 0�C for the sample as a
whole, aggregating the data in this fashion obscures
individual differences. The standard deviation of the
difference between abdominal skin and axillary temperature
was >/=0.5�C in 4 of 12 subjects. Thus the gradient
between abdominal skin and axillary temperatures is not a
consistent value, rather the difference between abdominal
skin and axillary temperature appears to fluctuate across
time within some subjects and to vary across subjects.
Ideally the gradient between comparable temperature sites
should be consistent. Within subjects, the correlation
between abdominal skin and axillary temperature was also
variable. Two of 12 subjects had r values >/= 0.85
while 4 subjects had r values < 0.5. Comparable
measures should be accurate and reproducible. Finally the
limits of agreement determined from a random sample of the
data indicate that approximately 95% of all differences
between abdominal skin and axillary temperature would lie
between �0.77 and 0.93�C, a wide spread, which may not be
acceptable for some clinical applications.
These findings suggest that abdominal skin and axillary
temperature may not consistently track each other over time.
The graphed data (Fig 1) illustrate this point. The first
portion of the recording shows very close correspondence of
axillary and abdominal skin temperature, compared with the
later portion. There are three likely contributors to the
correspondence of abdominal skin and axillary temperature.
First, both sites reflect skin blood flow, which may vary
based on the infant's thermoregulatory status. Second, the
degree of probe insulation will alter the recorded
temperature. While insulated, reflective probe covers were
used in data collection, no control of clothing or covering
was implemented. Further, adduction of the arm, another form
of insulation, was not controlled, possibly influencing
axillary temperature. Third, probe adherence, is a concern.
While probes generally remained in place throughout the data
recording period, even minor movement of the probe can alter
the temperature recorded. These three factors should be
included in future studies of abdominal skin and axillary
temperature.
Evidence strongly supports the relationship between
infant temperature and mortality.[20] How, then,
should study results be applied to practice? The current
study does not answer questions regarding the superiority of
either abdominal skin or axilla as an estimate of core
temperature. The data do provide information regarding the
comparability of these two sites in a small sample of term
infants, however, caution is warranted in generalizing
beyond the study sample. Evidence regarding comparability of
temperature monitoring sites is relevant to clinical
decision making. It is not reasonable to assume that the
gradient between abdominal skin and axillary temperatures is
consistent across time nor that changes in temperature
recorded from these sites are entirely parallel.
Whether abdominal skin or axillary temperature is
selected for continuous monitoring of an infant, findings
suggest that the type of site should be used consistently.
Switching between axillary and abdominal skin sites may
increase measurement error. The results also suggest that
choice of temperature site should be individualized. Factors
such as infant size and amount of tissue insulation,
external insulation, positioning needs, and skin integrity
may influence the comparability of abdominal skin and
axillary temperature.[15,21,22] Further, probe
adherence and consistent insulation are critical for
accurate continuous skin temperature measurement.
When using either abdominal skin or the axilla to
continuously monitor temperature, it is important to recall
that neither site is an ideal estimate of core temperature.
Additionally, several factors contribute to measurement
error in skin temperature. Continuous recordings of
temperature should be evaluated for trends and pattern. The
goal is a picture over time, rather than one isolated
measure in time. Although the temperature of infants
monitored continuously is typically documented in the
patient record, graphing the temperature not only helps
visual identification of infant temperature pattern, but can
also help diagnose problems with the probe itself. The
monitor display of abdominal skin or axillary temperature is
one of numerous pieces of data used in clinical decision
making. Nursing judgment remains a key element in
thermal care. (My
emphasis)
Interesting: from Medscape: only page 5 of 5. MM
