Deidra Huckabee MSN, RN, CCRN
Research Question
 Medical ICU staff inquired about the
accuracy of utilizing the bedside Point of
Care Testing (POCT) analyzer and standard
laboratory analysis of samples transported
via Pneumatic tube system
Rationale
 POCT assessment of arterial blood gases is
an increasingly common method of
measurement for guiding ventilator
management in ICU’s.
Rationale
 The team observed discrepancies in PaO2
values between our POCT analyzer (the iStat) and blood gas specimens transported
to our laboratory via the pneumatic tube
system (PTS).
Rationale
 The purpose of this study was to determine
accuracy of PaO2 values obtained via:
 POCT analyzer
 PTS system
 Hand delivery to the laboratory
Methods
 The project took place in the Medical ICU in
2 stages
 Stage 1
12 patient blood gases were analyzed per
bedside i-Stat and by a blood specimen to be
tested in the lab.
Methods
 Stage 1
12 patient blood gases were analyzed per bedside iStat and by a blood specimen to be tested in the lab.
 After evaluation 8 of the 12 specimens has PaO2
difference great than 10mmHg
 This was considered clinically significant and
moved the analysis into the next stage
Method
 Stage 2
 18 samples were drawn from different
patients with three different types of testing:
 Bedside i-Stat
 Sending blood gas to the lab
 Walking blood gas to the lab
Results
 The results were obtained via a two-sided,
dependent paired t-test
 The largest variation in PaO2 results was
found between samples sent via PTS versus
POCT and specimens walked to the
laboratory.
Results
 The mean difference between POCT
analysis and samples sent via PTS was 18.4
mm Hg (95% Cl 9.4-27.4mmHg)
 The mean difference between walked
samples and PTS samples was 9.7 mmHg (
95% Cl 5.9-13.5 mmHg)
Results
 The results were obtained via a two-sided,
dependent paired t-test
 The specimens that were tested at the bedside
using an i-Stat monitor and the specimen walked
to the lab had similar PaO2 results.
 The specimen sent through PTS has consistent
higher PaO2 results than the other 2 methods
Conclusion
 Arterial blood gas samples sent via PTS have
more PaO2 variability in PaO2 results than
samples tested using POCT or walked to the
lab.
Why?
 May be due to air bubbles which are mixed
in the sample when transported via PTS
This theory is also supported by the
observation of consistently lower PaO2
values obtained via POCT which might avoid
the introduction of microscopic air resulting
from transport
Change in Practice
 MUHA now has a policy in place for all
ICU’s to tube blood gas testing via POCT or
walk them to the lab to obtain the most
accurate results.