Title of Paper: Is pulse oximeter a reliable tool
for non-critically ill patients with COVID-19?
Abstract
Introduction: Guidelines recommend using a pulse oximeter
rather than arterial blood gas (ABG) for COVID-19 patients. However,
significant differences can be observed between oxygen saturation
measured by pulse oximetry (SpO2) and arterial oxygen
saturation (SaO2) in some clinical conditions. We aimed
to assess the reliability of pulse oximeter in patients with COVID-19
Methods: We retrospectively reviewed ABG analyses and SpO2
levels measured simultaneously with ABG in patients hospitalized in
COVID-19 wards.
Results : We categorized total 117 patients into two groups; in
whom the difference between SpO2 and
SaO2 was ≤4% (acceptable difference) and
>4% (large difference). Large difference group exhibited
higher neutrophil count, C-reactive protein, ferritin, fibrinogen,
D-dimer and lower lymphocyte count. Multivariate analyses revealed that
increased fibrinogen, increased ferritin and decreased lymphocyte count
were independent risk factors for large difference between
SpO2 and SaO2. The total study group
demonstrated the negative bias of 4.02% with the limits of agreement of
−9.22% to 1.17%. The bias became significantly higher in patients with
higher ferritin, fibrinogen levels and lower lymphocyte count.
Conclusion: Pulse oximeters may not be sufficient to assess
actual oxygen saturation especially in COVID-19 patients with high
ferritin and fibrinogen levels and low lymphocyte count low
SpO2 measurements.
Keywords pulse oximeter, hypoxemia, oxygen saturation, arterial
blood gas, coronavirus, COVID-19