Does COVID-19 really impact on the oxy-hemoglobin dissociation curve?

The COVID-19 pandemic has had a crucial impact on lifestyle worldwide. In this way, many studies have been presented, leading to continuous revaluation and questioning of conducts and concepts. Such is the case of the Chinese study suggesting that the new coronavirus has the potential to code anomalous nonstructural proteins capable of dissociating the iron atom from the porphyrin structure, contributing significantly to the characteristic hypoxemia conditions of the disease. Considering the potential impacts of those findings, the current study aims to evaluate and measure the dissociation curve of oxy-hemoglobin in COVID-19 patients. The project consists of a retrospective cohort study with data regarding oximetry and hemoglobin levels collected from digital patients records. The correlation between the measures and estimated values by Spearmen test was 0.843 (P < .001). A multiple linear regression model was applied using measured SO2 as a predicted variable and hemoglobin, PO2, and pH levels as predictors. The coefficients were pH 0.16-0.31 (P < .001); PO2 0.52-0.66 (P < .001) and Hb 0.088-0.059 (P = .706). Despite its limitations, the present study suggests that, at least in situations of clinical severity, the proposed mechanism does not appear to be universal or to have a significant clinical impact.