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.