Respiratory Rate Monitoring In Patients Receiving
Procedural Sedation And Analgesia For Upper
Gastrointestinal Endoscopy
BACKGROUND The Nellcor 2.0 is a new non-invasive monitor,
which measures the oxygen saturation using a finger sensor and
calculates the respiratory rate (RRoxi) based on the plethysmogram,
a curve which reflects the amount of vascular filling. The aim of
this study was to investigate the clinical feasibility of
implementation of the Nellcor 2.0 in patients receiving procedural
sedation and analgesia (PSA) for upper gastrointestinal endoscopy,
and to determine the level of agreement with the capnography
waveform based respiratory rate as gold standard.
METHOD Twenty-four patients undergoing upper gastrointestinal
endoscopy were monitored during the administration of PSA. The
acquired respiratory data of the Nellcor 2.0 (RRoxi) were compared
to the simultaneously acquired end-tidal CO2 reference rate
(RRETCO2).
RESULTS A total of 1054 minutes of respiratory data were
collected. The median percentage of monitored procedure time the
Nellcor 2.0 did not report respiratory rate was 15.5 % (8.6 – 27.7
%), yielding a total of 885 paired observations. The mean
measured respiratory rate for the reference method was 12.4 brpm,
ranging from 0 to 36 brpm. Mean difference between respiratory
rate measurements ± standard deviation was 5.78 ± 8.58 brpm,
with 95 % limits of agreement from – 11.03 to 22.59 brpm. The
linear correlation coefficient of the regression analysis between the
average of measured respiratory rate of both monitors and the
difference was – 0.55 (p < 0.0001). Additional analyses were
performed, distinguishing between respiratory rates from 4 to 11
brpm and respiratory rates above 12 brpm. The mean difference
between measurements of respiratory rates from 4 to 11 brpm was
1.71 ± 3.00 brpm, with 95 % limits of agreement from – 4.17 to
7.60 brpm. For higher respiratory rates the mean difference was –
0.50 ± 3.18 brpm, with 95 % limits of agreement from – 5.72 to
6.73 brpm.
CONCLUSION The results of this study suggest that the Nellcor
2.0 is not clinical feasible in the setting of patients receiving
procedural sedation and analgesia for upper gastrointestinal
endoscopies. The agreement between RRoxi and RRETCO2 decreased
along with decreasing respiratory rates.