Introduction
Coronavirus disease 2019 (COVID-19) caused by severe acute respiratory
syndrome coronavirus 2 (SARS-CoV-2), has quickly become a global
pandemic since it was first reported in December 2019. Patients with
COVID-19 need different levels of hospital care because of hypoxemic
respiratory failure 1. Monitoring oxygenation status
and providing effective oxygen therapy on time is also essential on
these patients 2. Arterial blood gas analysis (ABG) is
considered the gold standard in assessing oxygenation but it is an
invasive, painful, and expensive procedure therefore inconvenient for
frequent monitorization. Pulse oximeter has been developed as a safer
noninvasive alternative to ABG analysis and has become the standard of
care to assess oxygenation in clinical practice, which utilizes the
different light absorption of spectra of oxygenated and deoxygenated
hemoglobin. It was found that the expected error for a single
measurement of oxygen saturation measured by pulse oximetry
(SpO2) is 3%–4%. But, the deviation of
SpO2 from oxygen saturation in the arterial blood
(SaO2) is even more significant at saturations below
70%. Furthermore, SpO2 can underestimate SaO2 in low
perfusion states, arrhythmias, vasoconstriction, edema and severe anemia3-5.
In our clinic, we observed that SpO2 levels were lower
than the SaO2 in most COVID-19 patients. A study by
Wilson‐Baig et al. suggested that SpO2 does not reliably
predict SaO2 in critical care patients with COVID-196. Also, previous data proposed that
SpO2 is an unreliable surrogate marker for SaO2 in
critically ill patients 7. But the data is lacking
about SpO2 accuracy in hospitalized non-critically ill
COVID-19 patients.
We aimed to determine the reliability of pulse oximetry in
non-critically ill patients who were hospitalized in wards due to
COVID-19.